update

Reviewed-on: #7

AI_prompt.txt

@@ -12,3 +12,4 @@ Role: Principal Systems Architect & Lead Software Engineer.Objective: Implement
 
 
 
+Create a walkthrough for Julia service-A service sending a mix-content chat message to Julia service-B. the chat message must includes 

Manifest.toml

@@ -1,8 +1,8 @@
 # This file is machine-generated - editing it directly is not advised
 
-julia_version = "1.12.4"
+julia_version = "1.12.5"
 manifest_format = "2.0"
-project_hash = "be1e3c2d8b7f4f0ee7375c94aaf704ce73ba57b9"
+project_hash = "b632f853bcf5355f5c53ad3efa7a19f70444dc6c"
 
 [[deps.AliasTables]]
 deps = ["PtrArrays", "Random"]
@@ -436,6 +436,12 @@ git-tree-sha1 = "d9d9a189fb9155a460e6b5e8966bf6a66737abf8"
 uuid = "55e73f9c-eeeb-467f-b4cc-a633fde63d2a"
 version = "0.1.0"
 
+[[deps.NATSBridge]]
+deps = ["Arrow", "DataFrames", "Dates", "GeneralUtils", "HTTP", "JSON", "NATS", "PrettyPrinting", "Revise", "UUIDs"]
+path = "."
+uuid = "f2724d33-f338-4a57-b9f8-1be882570d10"
+version = "0.4.1"
+
 [[deps.NanoDates]]
 deps = ["Dates", "Parsers"]
 git-tree-sha1 = "850a0557ae5934f6e67ac0dc5ca13d0328422d1f"

Plik_API_document.md

@@ -1,194 +0,0 @@
-### API
-Plik server expose a REST-full API to manage uploads and get files :
-
-Get and create upload :
- 
-   - **POST**        /upload
-     - Params (json object in request body) :
-      - oneshot (bool)
-      - stream (bool)
-      - removable (bool)
-      - ttl (int)
-      - login (string)
-      - password (string)
-      - files (see below)
-     - Return :
-         JSON formatted upload object.
-         Important fields :
-           - id (required to upload files)
-           - uploadToken (required to upload/remove files)
-           - files (see below)
-
-   For stream mode you need to know the file id before the upload starts as it will block.
-   File size and/or file type also need to be known before the upload starts as they have to be printed 
-   in HTTP response headers.
-   To get the file ids pass a "files" json object with each file you are about to upload.
-   Fill the reference field with an arbitrary string to avoid matching file ids using the fileName field.
-   This is also used to notify of MISSING files when file upload is not yet finished or has failed.
-  ```
-  "files" : [
-    {
-      "fileName": "file.txt",
-      "fileSize": 12345,
-      "fileType": "text/plain",
-      "reference": "0"
-    },...
-  ]
-  ```
-  
-   - **GET** /upload/:uploadid:
-     - Get upload metadata (files list, upload date, ttl,...)
-
-Upload file :
-
-   - **POST** /$mode/:uploadid:/:fileid:/:filename:
-     - Request body must be a multipart request with a part named "file" containing file data.
-
-   - **POST** /file/:uploadid:
-     - Same as above without passing file id, won't work for stream mode.
-     
-   - **POST** /:
-     - Quick mode, automatically create an upload with default parameters and add the file to it.
-
-Get file :
-
-  - **HEAD** /$mode/:uploadid:/:fileid:/:filename:
-    - Returns only HTTP headers. Useful to know Content-Type and Content-Length without downloading the file. Especially if upload has OneShot option enabled.
-
-  - **GET**  /$mode/:uploadid:/:fileid:/:filename:
-    - Download file. Filename **MUST** match. A browser, might try to display the file if it's a jpeg for example. You may try to force download with ?dl=1 in url.
-
-  - **GET**  /archive/:uploadid:/:filename:
-    - Download uploaded files in a zip archive. :filename: must end with .zip
-
-Remove file :
-
-   - **DELETE** /$mode/:uploadid:/:fileid:/:filename:
-     - Delete file. Upload **MUST** have "removable" option enabled.
-
-Show server details :
-
-   - **GET** /version
-     - Show plik server version, and some build information (build host, date, git revision,...)
-
-   - **GET** /config
-     - Show plik server configuration (ttl values, max file size, ...)
-
-   - **GET** /stats
-     - Get server statistics ( upload/file count, user count, total size used )
-     - Admin only
-
-User authentication :
-
-   - 
-   Plik can authenticate users using Google and/or OVH third-party API.   
-   The /auth API is designed for the Plik web application nevertheless if you want to automatize it be sure to provide a valid
-   Referrer HTTP header and forward all session cookies.   
-   Plik session cookies have the "secure" flag set, so they can only be transmitted over secure HTTPS connections.   
-   To avoid CSRF attacks the value of the plik-xsrf cookie MUST be copied in the X-XSRFToken HTTP header of each
-   authenticated request.   
-   Once authenticated a user can generate upload tokens. Those tokens can be used in the X-PlikToken HTTP header used to link
-   an upload to the user account. It can be put in the ~/.plikrc file of the Plik command line client.   
-   
-   - **Local** :
-      - You'll need to create users using the server command line
-   
-   - **Google** :
-      - You'll need to create a new application in the [Google Developper Console](https://console.developers.google.com)
-      - You'll be handed a Google API ClientID and a Google API ClientSecret that you'll need to put in the plikd.cfg file
-      - Do not forget to whitelist valid origin and redirect url ( https://yourdomain/auth/google/callback ) for your domain
-   
-   - **OVH** :
-      - You'll need to create a new application in the OVH API : https://eu.api.ovh.com/createApp/
-      - You'll be handed an OVH application key and an OVH application secret key that you'll need to put in the plikd.cfg file
-
-   - **GET** /auth/google/login
-      - Get Google user consent URL. User have to visit this URL to authenticate
-
-   - **GET** /auth/google/callback
-     - Callback of the user consent dialog
-     - The user will be redirected back to the web application with a Plik session cookie at the end of this call
-
-   - **GET** /auth/ovh/login
-     - Get OVH user consent URL. User have to visit this URL to authenticate
-     - The response will contain a temporary session cookie to forward the API endpoint and OVH consumer key to the callback
-
-   - **GET** /auth/ovh/callback
-     - Callback of the user consent dialog. 
-     - The user will be redirected back to the web application with a Plik session cookie at the end of this call
-
-   - **POST** /auth/local/login
-     - Params :
-       - login : user login
-       - password : user password
-
-   - **GET** /auth/logout
-     - Invalidate Plik session cookies
-
-   - **GET** /me
-     - Return basic user info ( ID, name, email ) and tokens
-
-   - **DELETE** /me
-     - Remove user account.
-
-   - **GET** /me/token
-     - List user tokens
-      - This call use pagination
-
-   - **POST** /me/token
-     - Create a new upload token
-     - A comment can be passed in the json body
-
-   - **DELETE** /me/token/{token}
-     - Revoke an upload token
-
-   - **GET** /me/uploads
-     - List user uploads
-     - Params :
-        - token : filter by token
-      - This call use pagination
-
-   - **DELETE** /me/uploads
-     - Remove all uploads linked to a user account
-     - Params :
-        - token : filter by token
-
-   - **GET** /me/stats
-     - Get user statistics ( upload/file count, total size used )
-
-   - **GET** /users
-     - List all users
-     - This call use pagination
-     - Admin only 
-
-QRCode :
-
-   - **GET** /qrcode
-     - Generate a QRCode image from an url
-     - Params :
-        - url  : The url you want to store in the QRCode
-        - size : The size of the generated image in pixels (default: 250, max: 1000)
-
-
-$mode can be "file" or "stream" depending if stream mode is enabled. See FAQ for more details.
-
-Examples :
-```sh
-Create an upload (in the json response, you'll have upload id and upload token)
-$ curl -X POST http://127.0.0.1:8080/upload
-
-Create a OneShot upload
-$ curl -X POST -d '{ "OneShot" : true }' http://127.0.0.1:8080/upload
-
-Upload a file to upload
-$ curl -X POST --header "X-UploadToken: M9PJftiApG1Kqr81gN3Fq1HJItPENMhl" -F "file=@test.txt" http://127.0.0.1:8080/file/IsrIPIsDskFpN12E
-
-Get headers
-$ curl -I http://127.0.0.1:8080/file/IsrIPIsDskFpN12E/sFjIeokH23M35tN4/test.txt
-HTTP/1.1 200 OK
-Content-Disposition: filename=test.txt
-Content-Length: 3486
-Content-Type: text/plain; charset=utf-8
-Date: Fri, 15 May 2015 09:16:20 GMT
-
-```

Project.toml

@@ -1,8 +1,21 @@
+name = "NATSBridge"
+uuid = "f2724d33-f338-4a57-b9f8-1be882570d10"
+version = "0.4.3"
+authors = ["narawat <narawat@gmail.com>"]
+
 [deps]
 Arrow = "69666777-d1a9-59fb-9406-91d4454c9d45"
+Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
+DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 GeneralUtils = "c6c72f09-b708-4ac8-ac7c-2084d70108fe"
 HTTP = "cd3eb016-35fb-5094-929b-558a96fad6f3"
 JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
 NATS = "55e73f9c-eeeb-467f-b4cc-a633fde63d2a"
+PrettyPrinting = "54e16d92-306c-5ea0-a30b-337be88ac337"
+Revise = "295af30f-e4ad-537b-8983-00126c2a3abe"
 UUIDs = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
+
+[compat]
+Base64 = "1.11.0"
+JSON = "1.4.0"

README.md

@@ -0,0 +1,968 @@
+# NATSBridge
+
+A high-performance, bi-directional data bridge between **Julia**, **JavaScript**, and **Python/Micropython** applications using NATS (Core & JetStream), implementing the Claim-Check pattern for large payloads.
+
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+[![NATS](https://img.shields.io/badge/NATS-Enabled-green.svg)](https://nats.io)
+
+---
+
+## Table of Contents
+
+- [Overview](#overview)
+- [Features](#features)
+- [Architecture](#architecture)
+- [Installation](#installation)
+- [Quick Start](#quick-start)
+- [API Reference](#api-reference)
+- [Payload Types](#payload-types)
+- [Transport Strategies](#transport-strategies)
+- [Examples](#examples)
+- [Testing](#testing)
+- [License](#license)
+
+---
+
+## Overview
+
+NATSBridge enables seamless communication across Julia, JavaScript, and Python/Micropython applications through NATS, with intelligent transport selection based on payload size:
+
+| Transport | Payload Size | Method |
+|-----------|--------------|--------|
+| **Direct** | < 1MB | Sent directly via NATS (Base64 encoded) |
+| **Link** | >= 1MB | Uploaded to HTTP file server, URL sent via NATS |
+
+### Use Cases
+
+- **Chat Applications**: Text, images, audio, video in a single message
+- **File Transfer**: Efficient transfer of large files using claim-check pattern
+- **Streaming Data**: Sensor data, telemetry, and analytics pipelines
+- **Cross-Platform Communication**: Julia ↔ JavaScript ↔ Python/Micropython
+- **IoT Devices**: Micropython devices sending data to cloud services
+
+---
+
+## Features
+
+- ✅ **Bi-directional messaging** between Julia, JavaScript, and Python/Micropython
+- ✅ **Multi-payload support** - send multiple payloads with different types in one message
+- ✅ **Automatic transport selection** - direct vs link based on payload size
+- ✅ **Claim-Check pattern** for payloads > 1MB
+- ✅ **Apache Arrow IPC** support for tabular data (zero-copy reading)
+- ✅ **Exponential backoff** for reliable file server downloads
+- ✅ **Correlation ID tracking** for message tracing
+- ✅ **Reply-to support** for request-response patterns
+- ✅ **JetStream support** for message replay and durability
+- ✅ **Lightweight Micropython implementation** for microcontrollers
+
+---
+
+## Architecture
+
+### System Components
+
+```
+┌─────────────────────────────────────────────────────────────────────┐
+│                     NATSBridge Architecture                         │
+├─────────────────────────────────────────────────────────────────────┤
+│  ┌──────────────┐    ┌──────────────┐    ┌──────────────┐           │
+│  │   Julia      │    │  JavaScript  │    │  Python/     │           │
+│  │  (NATS.jl)   │◄──►│  (nats.js)   │◄──►│  Micropython │           │
+│  └──────────────┘    └──────────────┘    └──────────────┘           │
+│       │                    │                    │                   │
+│       ▼                    ▼                    ▼                   │
+│    ┌─────────────────────────────────────────────────────┐          │
+│    │                    NATS                             │          │
+│    │               (Message Broker)                      │          │
+│    └─────────────────────────────────────────────────────┘          │
+│                              │                                      │
+│                              ▼                                      │
+│                    ┌──────────────────────┐                         │
+│                    │  File Server         │                         │
+│                    │  (HTTP Upload/Get)   │                         │
+│                    └──────────────────────┘                         │
+└─────────────────────────────────────────────────────────────────────┘
+```
+
+### Message Flow
+
+1. **Sender** creates a message envelope with payloads
+2. **NATSBridge** serializes and encodes payloads based on type
+3. **Transport Decision**: Small payloads go directly to NATS, large payloads are uploaded to file server
+4. **NATS** routes messages to subscribers
+5. **Receiver** fetches payloads (from NATS or file server)
+6. **NATSBridge** deserializes and decodes payloads
+
+---
+
+## Installation
+
+### Prerequisites
+
+- **NATS Server** (v2.10+ recommended)
+- **HTTP File Server** (optional, for payloads > 1MB)
+
+### Julia
+
+```julia
+using Pkg
+Pkg.add("NATS")
+Pkg.add("https://git.yiem.cc/ton/NATSBridge")
+```
+
+### JavaScript
+
+```bash
+npm install nats.js apache-arrow uuid base64-url
+```
+
+For Node.js:
+```javascript
+const { smartsend, smartreceive } = require('./src/NATSBridge');
+```
+
+For browser:
+```html
+<script src="./src/NATSBridge.js"></script>
+<script>
+  // NATSBridge is available as window.NATSBridge
+</script>
+```
+
+### Python/Micropython
+
+1. Copy [`src/nats_bridge.py`](src/nats_bridge.py) to your device
+2. Install dependencies:
+
+**For Python (desktop):**
+```bash
+pip install nats-py
+```
+
+**For Micropython:**
+- `urequests` for HTTP requests (built-in for ESP32)
+- `base64` for base64 encoding (built-in)
+- `json` for JSON handling (built-in)
+
+---
+
+## Quick Start
+
+### Step 1: Start NATS Server
+
+```bash
+docker run -p 4222:4222 nats:latest
+```
+
+### Step 2: Start HTTP File Server (Optional)
+
+```bash
+# Create a directory for file uploads
+mkdir -p /tmp/fileserver
+
+# Use Python's built-in server
+python3 -m http.server 8080 --directory /tmp/fileserver
+```
+
+### Step 3: Send Your First Message
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+# Send a text message
+data = [("message", "Hello World", "text")]
+env, env_json_str = smartsend("/chat/room1", data, nats_url="nats://localhost:4222")
+print("Message sent!")
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+// Send a text message
+const { env, env_json_str } = await smartsend("/chat/room1", [
+    { dataname: "message", data: "Hello World", type: "text" }
+], { natsUrl: "nats://localhost:4222" });
+
+console.log("Message sent!");
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+# Send a text message
+data = [("message", "Hello World", "text")]
+env, env_json_str = NATSBridge.smartsend("/chat/room1", data; nats_url="nats://localhost:4222")
+println("Message sent!")
+```
+
+### Step 4: Receive Messages
+
+#### Python/Micropython
+
+```python
+import nats
+import asyncio
+from nats_bridge import smartreceive
+
+# Configuration
+SUBJECT = "/chat/room1"
+NATS_URL = "nats://localhost:4222"
+
+async def main():
+    # Connect to NATS
+    nc = await nats.connect(NATS_URL)
+    
+    # Subscribe to the subject - msg comes from the callback
+    async def message_handler(msg):
+        # Receive and process message
+        env = smartreceive(msg.data)
+        for dataname, data, type in env["payloads"]:
+            print(f"Received {dataname}: {data}")
+    
+    sid = await nc.subscribe(SUBJECT, cb=message_handler)
+    await asyncio.sleep(120)  # Keep listening
+    await nc.close()
+
+asyncio.run(main())
+```
+
+#### JavaScript
+
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+const { connect } = require('nats');
+
+// Configuration
+const SUBJECT = "/chat/room1";
+const NATS_URL = "nats://localhost:4222";
+
+async function main() {
+    // Connect to NATS
+    const nc = await connect({ servers: [NATS_URL] });
+    
+    // Subscribe to the subject - msg comes from the async iteration
+    const sub = nc.subscribe(SUBJECT);
+    
+    for await (const msg of sub) {
+        // Receive and process message
+        const env = await smartreceive(msg);
+        for (const payload of env.payloads) {
+            console.log(`Received ${payload.dataname}: ${payload.data}`);
+        }
+    }
+}
+
+main();
+```
+
+#### Julia
+
+```julia
+using NATS, NATSBridge
+
+# Configuration
+const SUBJECT = "/chat/room1"
+const NATS_URL = "nats://localhost:4222"
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] $message")
+end
+
+# Receiver: Listen for messages - msg comes from the callback
+function test_receive()
+    conn = NATS.connect(NATS_URL)
+    NATS.subscribe(conn, SUBJECT) do msg
+        log_trace("Received message on $(msg.subject)")
+        
+        # Receive and process message
+        env, env_json_str = NATSBridge.smartreceive(msg, fileserverDownloadHandler)
+        for (dataname, data, type) in env["payloads"]
+            println("Received $dataname: $data")
+        end
+    end
+    
+    # Keep listening for 120 seconds
+    sleep(120)
+    NATS.drain(conn)
+end
+
+test_receive()
+```
+
+---
+
+## API Reference
+
+### smartsend
+
+Sends data either directly via NATS or via a fileserver URL, depending on payload size.
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+env, env_json_str = smartsend(
+    subject,                           # NATS subject to publish to
+    data,                              # List of (dataname, data, type) tuples
+    nats_url="nats://localhost:4222",  # NATS server URL
+    fileserver_url="http://localhost:8080",  # File server URL
+    fileserver_upload_handler=plik_oneshot_upload,  # Upload handler function
+    size_threshold=1_000_000,          # Threshold in bytes (default: 1MB)
+    correlation_id=None,               # Optional correlation ID for tracing
+    msg_purpose="chat",                # Message purpose
+    sender_name="NATSBridge",          # Sender name
+    receiver_name="",                  # Receiver name (empty = broadcast)
+    receiver_id="",                    # Receiver UUID (empty = broadcast)
+    reply_to="",                       # Reply topic
+    reply_to_msg_id="",                # Reply message ID
+    is_publish=True                    # Whether to automatically publish to NATS
+)
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+const { env, env_json_str } = await smartsend(
+    subject,                           // NATS subject
+    data,                              // Array of {dataname, data, type}
+    {
+        natsUrl: "nats://localhost:4222",
+        fileserverUrl: "http://localhost:8080",
+        fileserverUploadHandler: customUploadHandler,
+        sizeThreshold: 1_000_000,
+        correlationId: "custom-id",
+        msgPurpose: "chat",
+        senderName: "NATSBridge",
+        receiverName: "",
+        receiverId: "",
+        replyTo: "",
+        replyToMsgId: "",
+        isPublish: true                  // Whether to automatically publish to NATS
+    }
+);
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+env, env_json_str = NATSBridge.smartsend(
+    subject,                           # NATS subject
+    data::AbstractArray{Tuple{String, Any, String}};  # List of (dataname, data, type)
+    nats_url::String = "nats://localhost:4222",
+    fileserver_url = "http://localhost:8080",
+    fileserverUploadHandler::Function = plik_oneshot_upload,
+    size_threshold::Int = 1_000_000,
+    correlation_id::Union{String, Nothing} = nothing,
+    msg_purpose::String = "chat",
+    sender_name::String = "NATSBridge",
+    receiver_name::String = "",
+    receiver_id::String = "",
+    reply_to::String = "",
+    reply_to_msg_id::String = "",
+    is_publish::Bool = true            # Whether to automatically publish to NATS
+)
+# Returns: (msgEnvelope_v1, JSON string)
+# - env: msgEnvelope_v1 object with all envelope metadata and payloads
+# - env_json_str: JSON string representation of the envelope for publishing
+```
+
+### smartreceive
+
+Receives and processes messages from NATS, handling both direct and link transport.
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartreceive
+
+# Note: For nats-py, use msg.data to pass the raw message data
+env = smartreceive(
+    msg.data,                          # NATS message data (msg.data for nats-py)
+    fileserver_download_handler=_fetch_with_backoff,  # Download handler
+    max_retries=5,                     # Max retry attempts
+    base_delay=100,                    # Initial delay in ms
+    max_delay=5000                     # Max delay in ms
+)
+# Returns: Dict with envelope metadata and 'payloads' field
+```
+
+#### JavaScript
+
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+
+// Note: msg is the NATS message object from subscription
+const env = await smartreceive(
+    msg,                               // NATS message (raw object from subscription)
+    {
+        fileserverDownloadHandler: customDownloadHandler,
+        maxRetries: 5,
+        baseDelay: 100,
+        maxDelay: 5000
+    }
+);
+// Returns: Object with envelope metadata and payloads array
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+# Note: msg is a NATS.Msg object passed from the subscription callback
+env, env_json_str = NATSBridge.smartreceive(
+    msg::NATS.Msg;
+    fileserverDownloadHandler::Function = _fetch_with_backoff,
+    max_retries::Int = 5,
+    base_delay::Int = 100,
+    max_delay::Int = 5000
+)
+# Returns: Dict with envelope metadata and payloads array
+```
+
+---
+
+## Payload Types
+
+| Type | Description | Serialization |
+|------|-------------|---------------|
+| `text` | Plain text strings | UTF-8 bytes |
+| `dictionary` | JSON-serializable dictionaries | JSON |
+| `table` | Tabular data (DataFrames, arrays) | Apache Arrow IPC |
+| `image` | Image data (PNG, JPG) | Raw bytes |
+| `audio` | Audio data (WAV, MP3) | Raw bytes |
+| `video` | Video data (MP4, AVI) | Raw bytes |
+| `binary` | Generic binary data | Raw bytes |
+
+---
+
+## Transport Strategies
+
+### Direct Transport (Payloads < 1MB)
+
+Small payloads are sent directly via NATS with Base64 encoding.
+
+#### Python/Micropython
+```python
+data = [("message", "Hello", "text")]
+smartsend("/topic", data)
+```
+
+#### JavaScript
+```javascript
+await smartsend("/topic", [
+    { dataname: "message", data: "Hello", type: "text" }
+]);
+```
+
+#### Julia
+```julia
+data = [("message", "Hello", "text")]
+smartsend("/topic", data)
+```
+
+### Link Transport (Payloads >= 1MB)
+
+Large payloads are uploaded to an HTTP file server.
+
+#### Python/Micropython
+```python
+data = [("file", large_data, "binary")]
+smartsend("/topic", data, fileserver_url="http://localhost:8080")
+```
+
+#### JavaScript
+```javascript
+await smartsend("/topic", [
+    { dataname: "file", data: largeData, type: "binary" }
+], { fileserverUrl: "http://localhost:8080" });
+```
+
+#### Julia
+```julia
+data = [("file", large_data, "binary")]
+smartsend("/topic", data; fileserver_url="http://localhost:8080")
+```
+
+---
+
+## Examples
+
+All examples include code for **Julia**, **JavaScript**, and **Python/Micropython** unless otherwise specified.
+
+### Example 1: Chat with Mixed Content
+
+Send text, small image, and large file in one message.
+
+#### Python/Micropython
+```python
+from nats_bridge import smartsend
+
+data = [
+    ("message_text", "Hello!", "text"),
+    ("user_avatar", image_data, "image"),
+    ("large_document", large_file_data, "binary")
+]
+
+env, env_json_str = smartsend("/chat/room1", data, fileserver_url="http://localhost:8080")
+```
+
+#### JavaScript
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+const { env, env_json_str } = await smartsend("/chat/room1", [
+    { dataname: "message_text", data: "Hello!", type: "text" },
+    { dataname: "user_avatar", data: image_data, type: "image" },
+    { dataname: "large_document", data: large_file_data, type: "binary" }
+], {
+    fileserverUrl: "http://localhost:8080"
+});
+```
+
+#### Julia
+```julia
+using NATSBridge
+
+data = [
+    ("message_text", "Hello!", "text"),
+    ("user_avatar", image_data, "image"),
+    ("large_document", large_file_data, "binary")
+]
+
+env, env_json_str = NATSBridge.smartsend("/chat/room1", data; fileserver_url="http://localhost:8080")
+```
+
+### Example 2: Dictionary Exchange
+
+Send configuration data between platforms.
+
+#### Python/Micropython
+```python
+from nats_bridge import smartsend
+
+config = {
+    "wifi_ssid": "MyNetwork",
+    "wifi_password": "password123",
+    "update_interval": 60
+}
+
+data = [("config", config, "dictionary")]
+env, env_json_str = smartsend("/device/config", data)
+```
+
+#### JavaScript
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+const config = {
+    wifi_ssid: "MyNetwork",
+    wifi_password: "password123",
+    update_interval: 60
+};
+
+const { env, env_json_str } = await smartsend("/device/config", [
+    { dataname: "config", data: config, type: "dictionary" }
+]);
+```
+
+#### Julia
+```julia
+using NATSBridge
+
+config = Dict(
+    "wifi_ssid" => "MyNetwork",
+    "wifi_password" => "password123",
+    "update_interval" => 60
+)
+
+data = [("config", config, "dictionary")]
+env, env_json_str = NATSBridge.smartsend("/device/config", data)
+```
+
+### Example 3: Table Data (Arrow IPC)
+
+Send tabular data using Apache Arrow IPC format.
+
+#### Python/Micropython
+```python
+import pandas as pd
+from nats_bridge import smartsend
+
+df = pd.DataFrame({
+    "id": [1, 2, 3],
+    "name": ["Alice", "Bob", "Charlie"],
+    "score": [95, 88, 92]
+})
+
+data = [("students", df, "table")]
+env, env_json_str = smartsend("/data/analysis", data)
+```
+
+#### JavaScript
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+const tableData = [
+    { id: 1, name: "Alice", score: 95 },
+    { id: 2, name: "Bob", score: 88 },
+    { id: 3, name: "Charlie", score: 92 }
+];
+
+const { env, env_json_str } = await smartsend("/data/analysis", [
+    { dataname: "students", data: tableData, type: "table" }
+]);
+```
+
+#### Julia
+```julia
+using NATSBridge
+using DataFrames
+
+df = DataFrame(
+    id = [1, 2, 3],
+    name = ["Alice", "Bob", "Charlie"],
+    score = [95, 88, 92]
+)
+
+data = [("students", df, "table")]
+env, env_json_str = NATSBridge.smartsend("/data/analysis", data)
+```
+
+### Example 4: Request-Response Pattern with Envelope JSON
+
+Bi-directional communication with reply-to support. The `smartsend` function now returns both the envelope object and a JSON string that can be published directly.
+
+#### Python/Micropython (Requester)
+```python
+from nats_bridge import smartsend
+
+env, env_json_str = smartsend(
+    "/device/command",
+    [("command", {"action": "read_sensor"}, "dictionary")],
+    reply_to="/device/response"
+)
+# env: msgEnvelope_v1 object
+# env_json_str: JSON string for publishing to NATS
+
+# The env_json_str can also be published directly using NATS request-reply pattern
+# nc.request("/device/command", env_json_str, reply_to="/device/response")
+```
+
+#### Python/Micropython (Responder)
+```python
+import nats
+import asyncio
+from nats_bridge import smartreceive, smartsend
+
+# Configuration
+SUBJECT = "/device/command"
+REPLY_SUBJECT = "/device/response"
+NATS_URL = "nats://localhost:4222"
+
+async def main():
+    nc = await nats.connect(NATS_URL)
+    
+    async def message_handler(msg):
+        env = smartreceive(msg.data)
+        for dataname, data, type in env["payloads"]:
+            if data.get("action") == "read_sensor":
+                response = {"sensor_id": "sensor-001", "value": 42.5}
+                smartsend(REPLY_SUBJECT, [("data", response, "dictionary")])
+    
+    sid = await nc.subscribe(SUBJECT, cb=message_handler)
+    await asyncio.sleep(120)
+    await nc.close()
+
+asyncio.run(main())
+```
+
+#### JavaScript (Requester)
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+const { env, env_json_str } = await smartsend("/device/command", [
+    { dataname: "command", data: { action: "read_sensor" }, type: "dictionary" }
+], {
+    replyTo: "/device/response"
+});
+```
+
+#### JavaScript (Responder)
+```javascript
+const { smartreceive, smartsend } = require('./src/NATSBridge');
+const { connect } = require('nats');
+
+// Configuration
+const SUBJECT = "/device/command";
+const REPLY_SUBJECT = "/device/response";
+const NATS_URL = "nats://localhost:4222";
+
+async function main() {
+    const nc = await connect({ servers: [NATS_URL] });
+    
+    const sub = nc.subscribe(SUBJECT);
+    
+    for await (const msg of sub) {
+        const env = await smartreceive(msg);
+        for (const payload of env.payloads) {
+            if (payload.dataname === "command" && payload.data.action === "read_sensor") {
+                const response = { sensor_id: "sensor-001", value: 42.5 };
+                await smartsend(REPLY_SUBJECT, [
+                    { dataname: "data", data: response, type: "dictionary" }
+                ]);
+            }
+        }
+    }
+}
+
+main();
+```
+
+#### Julia (Requester)
+```julia
+using NATSBridge
+
+env, env_json_str = NATSBridge.smartsend(
+    "/device/command",
+    [("command", Dict("action" => "read_sensor"), "dictionary")];
+    reply_to="/device/response"
+)
+```
+
+#### Julia (Responder)
+```julia
+using NATS, NATSBridge
+
+# Configuration
+const SUBJECT = "/device/command"
+const REPLY_SUBJECT = "/device/response"
+const NATS_URL = "nats://localhost:4222"
+
+function test_responder()
+    conn = NATS.connect(NATS_URL)
+    NATS.subscribe(conn, SUBJECT) do msg
+        env, env_json_str = NATSBridge.smartreceive(msg, fileserverDownloadHandler)
+        for (dataname, data, type) in env["payloads"]
+            if dataname == "command" && data["action"] == "read_sensor"
+                response = Dict("sensor_id" => "sensor-001", "value" => 42.5)
+                smartsend(REPLY_SUBJECT, [("data", response, "dictionary")])
+            end
+        end
+    end
+    
+    sleep(120)
+    NATS.drain(conn)
+end
+
+test_responder()
+```
+
+### Example 5: Micropython IoT Device
+
+Lightweight Micropython device sending sensor data.
+
+#### Micropython
+```python
+import nats
+import asyncio
+from nats_bridge import smartsend, smartreceive
+
+# Configuration
+SUBJECT = "/device/sensors"
+NATS_URL = "nats://localhost:4222"
+
+async def main():
+    nc = await nats.connect(NATS_URL)
+    
+    # Send sensor data
+    data = [("temperature", "25.5", "text"), ("humidity", 65, "dictionary")]
+    smartsend("/device/sensors", data, nats_url="nats://localhost:4222")
+    
+    # Receive commands - msg comes from the callback
+    async def message_handler(msg):
+        env = smartreceive(msg.data)
+        for dataname, data, type in env["payloads"]:
+            if type == "dictionary" and data.get("action") == "reboot":
+                # Execute reboot
+                pass
+    
+    sid = await nc.subscribe(SUBJECT, cb=message_handler)
+    await asyncio.sleep(120)
+    await nc.close()
+
+asyncio.run(main())
+```
+
+#### JavaScript (Receiver)
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+const { connect } = require('nats');
+
+// Configuration
+const SUBJECT = "/device/sensors";
+const NATS_URL = "nats://localhost:4222";
+
+async function main() {
+    const nc = await connect({ servers: [NATS_URL] });
+    
+    const sub = nc.subscribe(SUBJECT);
+    
+    for await (const msg of sub) {
+        const env = await smartreceive(msg);
+        for (const payload of env.payloads) {
+            if (payload.dataname === "temperature") {
+                console.log(`Temperature: ${payload.data}`);
+            } else if (payload.dataname === "humidity") {
+                console.log(`Humidity: ${payload.data}`);
+            }
+        }
+    }
+}
+
+main();
+```
+
+#### Julia (Receiver)
+```julia
+using NATS, NATSBridge
+
+# Configuration
+const SUBJECT = "/device/sensors"
+const NATS_URL = "nats://localhost:4222"
+
+function test_receiver()
+    conn = NATS.connect(NATS_URL)
+    NATS.subscribe(conn, SUBJECT) do msg
+        env, env_json_str = NATSBridge.smartreceive(msg, fileserverDownloadHandler)
+        for (dataname, data, type) in env["payloads"]
+            if dataname == "temperature"
+                println("Temperature: $data")
+            elseif dataname == "humidity"
+                println("Humidity: $data")
+            end
+        end
+    end
+    
+    sleep(120)
+    NATS.drain(conn)
+end
+
+test_receiver()
+```
+
+---
+
+## Testing
+
+Run the test scripts to verify functionality:
+
+### Python/Micropython
+
+```bash
+# Basic functionality test
+python test/test_micropython_basic.py
+
+# Text message exchange
+python test/test_micropython_text_sender.py
+python test/test_micropython_text_receiver.py
+
+# Dictionary exchange
+python test/test_micropython_dict_sender.py
+python test/test_micropython_dict_receiver.py
+
+# File transfer
+python test/test_micropython_file_sender.py
+python test/test_micropython_file_receiver.py
+
+# Mixed payload types
+python test/test_micropython_mixed_sender.py
+python test/test_micropython_mixed_receiver.py
+```
+
+### JavaScript
+
+```bash
+# Text message exchange
+node test/test_js_text_sender.js
+node test/test_js_text_receiver.js
+
+# Dictionary exchange
+node test/test_js_dict_sender.js
+node test/test_js_dict_receiver.js
+
+# File transfer
+node test/test_js_file_sender.js
+node test/test_js_file_receiver.js
+
+# Mixed payload types
+node test/test_js_mix_payload_sender.js
+node test/test_js_mix_payloads_receiver.js
+
+# Table exchange
+node test/test_js_table_sender.js
+node test/test_js_table_receiver.js
+```
+
+### Julia
+
+```julia
+# Text message exchange
+julia test/test_julia_text_sender.jl
+julia test/test_julia_text_receiver.jl
+
+# Dictionary exchange
+julia test/test_julia_dict_sender.jl
+julia test/test_julia_dict_receiver.jl
+
+# File transfer
+julia test/test_julia_file_sender.jl
+julia test/test_julia_file_receiver.jl
+
+# Mixed payload types
+julia test/test_julia_mix_payloads_sender.jl
+julia test/test_julia_mix_payloads_receiver.jl
+
+# Table exchange
+julia test/test_julia_table_sender.jl
+julia test/test_julia_table_receiver.jl
+```
+
+---
+
+## License
+
+MIT License
+
+Copyright (c) 2026 NATSBridge Contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

docs/IMPLEMENTATION.md

@@ -1,321 +0,0 @@
-# Implementation Guide: Bi-Directional Data Bridge
-
-## Overview
-
-This document describes the implementation of the high-performance, bi-directional data bridge between Julia and JavaScript services using NATS (Core & JetStream), implementing the Claim-Check pattern for large payloads.
-
-## Architecture
-
-The implementation follows the Claim-Check pattern:
-
-```
-┌─────────────────────────────────────────────────────────────────────────┐
-│                         SmartSend Function                              │
-└─────────────────────────────────────────────────────────────────────────┘
-                             │
-                             ▼
-┌─────────────────────────────────────────────────────────────────────────┐
-│  Is payload size < 1MB?                                                 │
-└─────────────────────────────────────────────────────────────────────────┘
-                             │
-           ┌─────────────────┴─────────────────┐
-           ▼                                   ▼
-     ┌─────────────────┐                 ┌─────────────────┐
-     │  Direct Path    │                 │  Link Path      │
-     │  (< 1MB)        │                 │  (> 1MB)        │
-     │                 │                 │                 │
-     │ • Serialize to  │                 │ • Serialize to  │
-     │   IOBuffer      │                 │   IOBuffer      │
-     │ • Base64 encode │                 │ • Upload to     │
-     │ • Publish to    │                 │   HTTP Server   │
-     │   NATS          │                 │ • Publish to    │
-     │                 │                 │   NATS with URL │
-     └─────────────────┘                 └─────────────────┘
-```
-
-## Files
-
-### Julia Module: [`src/julia_bridge.jl`](../src/julia_bridge.jl)
-
-The Julia implementation provides:
-
-- **[`MessageEnvelope`](../src/julia_bridge.jl)**: Struct for the unified JSON envelope
-- **[`SmartSend()`](../src/julia_bridge.jl)**: Handles transport selection based on payload size
-- **[`SmartReceive()`](../src/julia_bridge.jl)**: Handles both direct and link transport
-
-### JavaScript Module: [`src/js_bridge.js`](../src/js_bridge.js)
-
-The JavaScript implementation provides:
-
-- **`MessageEnvelope` class**: For the unified JSON envelope
-- **[`SmartSend()`](../src/js_bridge.js)**: Handles transport selection based on payload size
-- **[`SmartReceive()`](../src/js_bridge.js)**: Handles both direct and link transport
-
-## Installation
-
-### Julia Dependencies
-
-```julia
-using Pkg
-Pkg.add("NATS")
-Pkg.add("Arrow")
-Pkg.add("JSON3")
-Pkg.add("HTTP")
-Pkg.add("UUIDs")
-Pkg.add("Dates")
-```
-
-### JavaScript Dependencies
-
-```bash
-npm install nats.js apache-arrow uuid base64-url
-```
-
-## Usage Tutorial
-
-### Step 1: Start NATS Server
-
-```bash
-docker run -p 4222:4222 nats:latest
-```
-
-### Step 2: Start HTTP File Server (optional)
-
-```bash
-# Create a directory for file uploads
-mkdir -p /tmp/fileserver
-
-# Use any HTTP server that supports POST for file uploads
-# Example: Python's built-in server
-python3 -m http.server 8080 --directory /tmp/fileserver
-```
-
-### Step 3: Run Test Scenarios
-
-```bash
-# Scenario 1: Command & Control (JavaScript sender)
-node test/scenario1_command_control.js
-
-# Scenario 2: Large Arrow Table (JavaScript sender)
-node test/scenario2_large_table.js
-
-# Scenario 3: Julia-to-Julia communication
-# Run both Julia and JavaScript versions
-julia test/scenario3_julia_to_julia.jl
-node test/scenario3_julia_to_julia.js
-```
-
-## Usage
-
-### Scenario 1: Command & Control (Small JSON)
-
-#### JavaScript (Sender)
-```javascript
-const { SmartSend } = require('./js_bridge');
-
-const config = {
-    step_size: 0.01,
-    iterations: 1000
-};
-
-await SmartSend("control", config, "json", {
-    correlationId: "unique-id"
-});
-```
-
-#### Julia (Receiver)
-```julia
-using NATS
-using JSON3
-
-# Subscribe to control subject
-subscribe(nats, "control") do msg
-    env = MessageEnvelope(String(msg.data))
-    config = JSON3.read(env.payload)
-    
-    # Execute simulation with parameters
-    step_size = config.step_size
-    iterations = config.iterations
-    
-    # Send acknowledgment
-    response = Dict("status" => "Running", "correlation_id" => env.correlation_id)
-    publish(nats, "control_response", JSON3.stringify(response))
-end
-```
-
-### Scenario 2: Deep Dive Analysis (Large Arrow Table)
-
-#### Julia (Sender)
-```julia
-using Arrow
-using DataFrames
-
-# Create large DataFrame
-df = DataFrame(
-    id = 1:10_000_000,
-    value = rand(10_000_000),
-    category = rand(["A", "B", "C"], 10_000_000)
-)
-
-# Send via SmartSend with type="table"
-await SmartSend("analysis_results", df, "table");
-```
-
-#### JavaScript (Receiver)
-```javascript
-const { SmartReceive } = require('./js_bridge');
-
-const result = await SmartReceive(msg);
-
-// Use table data for visualization with Perspective.js or D3
-const table = result.data;
-```
-
-### Scenario 3: Live Binary Processing
-
-#### JavaScript (Sender)
-```javascript
-const { SmartSend } = require('./js_bridge');
-
-// Capture binary chunk
-const binaryData = await navigator.mediaDevices.getUserMedia({ binary: true });
-
-await SmartSend("binary_input", binaryData, "binary", {
-    metadata: {
-        sample_rate: 44100,
-        channels: 1
-    }
-});
-```
-
-#### Julia (Receiver)
-```julia
-using WAV
-using DSP
-
-# Receive binary data
-function process_binary(data)
-    # Perform FFT or AI transcription
-    spectrum = fft(data)
-    
-    # Send results back (JSON + Arrow table)
-    results = Dict("transcription" => "sample text", "spectrum" => spectrum)
-    await SmartSend("binary_output", results, "json")
-end
-```
-
-### Scenario 4: Catch-Up (JetStream)
-
-#### Julia (Producer)
-```julia
-using NATS
-
-function publish_health_status(nats)
-    jetstream = JetStream(nats, "health_updates")
-    
-    while true
-        status = Dict("cpu" => rand(), "memory" => rand())
-        publish(jetstream, "health", status)
-        sleep(5)  # Every 5 seconds
-    end
-end
-```
-
-#### JavaScript (Consumer)
-```javascript
-const { connect } = require('nats');
-
-const nc = await connect({ servers: ['nats://localhost:4222'] });
-const js = nc.jetstream();
-
-// Request replay from last 10 minutes
-const consumer = await js.pullSubscribe("health", { 
-    durable_name: "catchup",
-    max_batch: 100,
-    max_ack_wait: 30000
-});
-
-// Process historical and real-time messages
-for await (const msg of consumer) {
-    const result = await SmartReceive(msg);
-    // Process the data
-    msg.ack();
-}
-```
-
-## Configuration
-
-### Environment Variables
-
-| Variable | Default | Description |
-|----------|---------|-------------|
-| `NATS_URL` | `nats://localhost:4222` | NATS server URL |
-| `FILESERVER_URL` | `http://localhost:8080/upload` | HTTP file server URL |
-| `SIZE_THRESHOLD` | `1_000_000` | Size threshold in bytes (1MB) |
-
-### Message Envelope Schema
-
-```json
-{
-  "correlation_id": "uuid-v4-string",
-  "type": "json|table|binary",
-  "transport": "direct|link",
-  "payload": "base64-encoded-string",  // Only if transport=direct
-  "url": "http://fileserver/path/to/data",  // Only if transport=link
-  "metadata": {
-    "content_type": "application/octet-stream",
-    "content_length": 123456,
-    "format": "arrow_ipc_stream"
-  }
-}
-```
-
-## Performance Considerations
-
-### Zero-Copy Reading
-- Use Arrow's memory-mapped file reading
-- Avoid unnecessary data copying during deserialization
-- Use Apache Arrow's native IPC reader
-
-### Exponential Backoff
-- Maximum retry count: 5
-- Base delay: 100ms, max delay: 5000ms
-- Implemented in both Julia and JavaScript implementations
-
-### Correlation ID Logging
-- Log correlation_id at every stage
-- Include: send, receive, serialize, deserialize
-- Use structured logging format
-
-## Testing
-
-Run the test scripts:
-
-```bash
-# Scenario 1: Command & Control (JavaScript sender)
-node test/scenario1_command_control.js
-
-# Scenario 2: Large Arrow Table (JavaScript sender)
-node test/scenario2_large_table.js
-```
-
-## Troubleshooting
-
-### Common Issues
-
-1. **NATS Connection Failed**
-   - Ensure NATS server is running
-   - Check NATS_URL configuration
-
-2. **HTTP Upload Failed**
-   - Ensure file server is running
-   - Check FILESERVER_URL configuration
-   - Verify upload permissions
-
-3. **Arrow IPC Deserialization Error**
-   - Ensure data is properly serialized to Arrow format
-   - Check Arrow version compatibility
-
-## License
-
-MIT

docs/architecture.md

@@ -1,8 +1,112 @@
-# Architecture Documentation: Bi-Directional Data Bridge (Julia ↔ JavaScript)
+# Architecture Documentation: Bi-Directional Data Bridge
 
 ## Overview
 
-This document describes the architecture for a high-performance, bi-directional data bridge between a Julia service and a JavaScript (Node.js) service using NATS (Core & JetStream), implementing the Claim-Check pattern for large payloads.
+This document describes the architecture for a high-performance, bi-directional data bridge between **Julia**, **JavaScript**, and **Python/Micropython** applications using NATS (Core & JetStream), implementing the Claim-Check pattern for large payloads.
+
+The system enables seamless communication across all three platforms:
+- **Julia ↔ JavaScript** bi-directional messaging
+- **JavaScript ↔ Python/Micropython** bi-directional messaging
+- **Julia ↔ Python/Micropython** bi-directional messaging (via JSON serialization)
+
+### File Server Handler Architecture
+
+The system uses **handler functions** to abstract file server operations, allowing support for different file server implementations (e.g., Plik, AWS S3, custom HTTP server).
+
+**Handler Function Signatures:**
+
+```julia
+# Upload handler - uploads data to file server and returns URL
+# The handler is passed to smartsend as fileserver_upload_handler parameter
+# It receives: (file_server_url::String, dataname::String, data::Vector{UInt8})
+# Returns: Dict{String, Any} with keys: "status", "uploadid", "fileid", "url"
+fileserver_upload_handler(file_server_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
+
+# Download handler - fetches data from file server URL with exponential backoff
+# The handler is passed to smartreceive as fileserver_download_handler parameter
+# It receives: (url::String, max_retries::Int, base_delay::Int, max_delay::Int, correlation_id::String)
+# Returns: Vector{UInt8} (the downloaded data)
+fileserver_download_handler(url::String, max_retries::Int, base_delay::Int, max_delay::Int, correlation_id::String)::Vector{UInt8}
+```
+
+This design allows the system to support multiple file server backends without changing the core messaging logic.
+
+### Multi-Payload Support (Standard API)
+
+The system uses a **standardized list-of-tuples format** for all payload operations. **Even when sending a single payload, the user must wrap it in a list.**
+
+**API Standard:**
+```julia
+# Input format for smartsend (always a list of tuples with type info)
+[(dataname1, data1, type1), (dataname2, data2, type2), ...]
+
+# Output format for smartreceive (returns a dictionary with payloads field containing list of tuples)
+# Returns: Dict with envelope metadata and payloads field containing Vector{Tuple{String, Any, String}}
+# {
+#   "correlation_id": "...",
+#   "msg_id": "...",
+#   "timestamp": "...",
+#   "send_to": "...",
+#   "msg_purpose": "...",
+#   "sender_name": "...",
+#   "sender_id": "...",
+#   "receiver_name": "...",
+#   "receiver_id": "...",
+#   "reply_to": "...",
+#   "reply_to_msg_id": "...",
+#   "broker_url": "...",
+#   "metadata": {...},
+#   "payloads": [(dataname1, data1, type1), (dataname2, data2, type2), ...]
+# }
+```
+
+**Supported Types:**
+- `"text"` - Plain text
+- `"dictionary"` - JSON-serializable dictionaries (Dict, NamedTuple)
+- `"table"` - Tabular data (DataFrame, array of structs)
+- `"image"` - Image data (Bitmap, PNG/JPG bytes)
+- `"audio"` - Audio data (WAV, MP3 bytes)
+- `"video"` - Video data (MP4, AVI bytes)
+- `"binary"` - Generic binary data (Vector{UInt8})
+
+This design allows per-payload type specification, enabling **mixed-content messages** where different payloads can use different serialization formats in a single message.
+
+**Examples:**
+
+```julia
+# Single payload - still wrapped in a list
+smartsend(
+    "/test",
+    [("dataname1", data1, "dictionary")],  # List with one tuple (data, type)
+    broker_url="nats://localhost:4222",
+    fileserver_upload_handler=plik_oneshot_upload
+)
+
+# Multiple payloads in one message with different types
+smartsend(
+    "/test",
+    [("dataname1", data1, "dictionary"), ("dataname2", data2, "table")],
+    broker_url="nats://localhost:4222",
+    fileserver_upload_handler=plik_oneshot_upload
+)
+
+# Mixed content (e.g., chat with text, image, audio)
+smartsend(
+    "/chat",
+    [
+        ("message_text", "Hello!", "text"),
+        ("user_image", image_data, "image"),
+        ("audio_clip", audio_data, "audio")
+    ],
+    broker_url="nats://localhost:4222"
+)
+
+# Receive returns a dictionary envelope with all metadata and deserialized payloads
+env = smartreceive(msg; fileserver_download_handler=_fetch_with_backoff, max_retries=5, base_delay=100, max_delay=5000)
+# env["payloads"] = [("dataname1", data1, type1), ("dataname2", data2, type2), ...]
+# env["correlation_id"], env["msg_id"], etc.
+# env is a dictionary containing envelope metadata and payloads field
+```
 
 ## Architecture Diagram
 
@@ -34,38 +138,124 @@ flowchart TD
 
 ## System Components
 
-### 1. Unified JSON Envelope Schema
+### 1. msg_envelope_v1 - Message Envelope
 
-All messages use a standardized envelope format:
+The `msg_envelope_v1` structure provides a comprehensive message format for bidirectional communication between Julia, JavaScript, and Python/Micropython applications.
 
+**Julia Structure:**
+```julia
+struct msg_envelope_v1
+  correlation_id::String       # Unique identifier to track messages across systems
+  msg_id::String               # This message id
+  timestamp::String            # Message published timestamp
+  
+  send_to::String              # Topic/subject the sender sends to
+  msg_purpose::String          # Purpose of this message (ACK | NACK | updateStatus | shutdown | ...)
+  sender_name::String          # Sender name (e.g., "agent-wine-web-frontend")
+  sender_id::String            # Sender id (uuid4)
+  receiver_name::String        # Message receiver name (e.g., "agent-backend")
+  receiver_id::String          # Message receiver id (uuid4 or nothing for broadcast)
+  reply_to::String             # Topic to reply to
+  reply_to_msg_id::String      # Message id this message is replying to
+  broker_url::String           # NATS server address
+  
+  metadata::Dict{String, Any}
+  payloads::Vector{msg_payload_v1}  # Multiple payloads stored here
+end
+```
+
+**JSON Schema:**
 ```json
 {
   "correlation_id": "uuid-v4-string",
-  "type": "json|table|binary",
-  "transport": "direct|link",
-  "payload": "base64-encoded-string",  // Only if transport=direct
-  "url": "http://fileserver/path/to/data",  // Only if transport=link
+  "msg_id": "uuid-v4-string",
+  "timestamp": "2024-01-15T10:30:00Z",
+  
+  "send_to": "topic/subject",
+  "msg_purpose": "ACK | NACK | updateStatus | shutdown | chat",
+  "sender_name": "agent-wine-web-frontend",
+  "sender_id": "uuid4",
+  "receiver_name": "agent-backend",
+  "receiver_id": "uuid4",
+  "reply_to": "topic",
+  "reply_to_msg_id": "uuid4",
+  "broker_url": "nats://localhost:4222",
+  
   "metadata": {
-    "content_type": "application/octet-stream",
-    "content_length": 123456,
-    "format": "arrow_ipc_stream"
+
+  },
+  
+  "payloads": [
+    {
+      "id": "uuid4",
+      "dataname": "login_image",
+      "payload_type": "image",
+      "transport": "direct",
+      "encoding": "base64",
+      "size": 15433,
+      "data": "base64-encoded-string",
+      "metadata": {
+
       }
+    },
+    {
+      "id": "uuid4",
+      "dataname": "large_data",
+      "payload_type": "table",
+      "transport": "link",
+      "encoding": "none",
+      "size": 524288,
+      "data": "http://localhost:8080/file/UPLOAD_ID/FILE_ID/data.arrow",
+      "metadata": {
+
+      }
+    }
+  ]
 }
 ```
 
-### 2. Transport Strategy Decision Logic
+### 2. msg_payload_v1 - Payload Structure
+
+The `msg_payload_v1` structure provides flexible payload handling for various data types across all supported platforms.
+
+**Julia Structure:**
+```julia
+struct msg_payload_v1
+  id::String                    # Id of this payload (e.g., "uuid4")
+  dataname::String              # Name of this payload (e.g., "login_image")
+  payload_type::String          # "text | dictionary | table | image | audio | video | binary"
+  transport::String             # "direct | link"
+  encoding::String              # "none | json | base64 | arrow-ipc"
+  size::Integer                 # Data size in bytes
+  data::Any                     # Payload data in case of direct transport or a URL in case of link
+  metadata::Dict{String, Any}   # Dict("checksum" => "sha256_hash", ...)
+end
+```
+
+**Key Features:**
+- Supports multiple data types: text, dictionary, table, image, audio, video, binary
+- Flexible transport: "direct" (NATS) or "link" (HTTP fileserver)
+- Multiple payloads per message (essential for chat with mixed content)
+- Per-payload and per-envelope metadata support
+
+### 3. Transport Strategy Decision Logic
 
 ```
 ┌─────────────────────────────────────────────────────────────┐
-│                     SmartSend Function                        │
+│                     smartsend Function                      │
+│  Accepts: [(dataname1, data1, type1), ...]                  │
+│  (Type is per payload, not standalone)                      │
 └─────────────────────────────────────────────────────────────┘
                              │
                              ▼
 ┌─────────────────────────────────────────────────────────────┐
-│  Is payload size < 1MB?                                     │
+│  For each payload:                                          │
+│  1. Extract type from tuple                                 │
+│  2. Serialize based on type                                 │
+│  3. Check payload size                                      │
 └─────────────────────────────────────────────────────────────┘
                              │
-          ┌─────────────────┴─────────────────┐
+            ┌────────────────┴─-────────────────┐
             ▼                                   ▼
       ┌─────────────────┐                 ┌─────────────────┐
       │  Direct Path    │                 │  Link Path      │
@@ -76,23 +266,82 @@ All messages use a standardized envelope format:
       │ • Base64 encode │                 │ • Upload to     │
       │ • Publish to    │                 │   HTTP Server   │
       │   NATS          │                 │ • Publish to    │
-    │                 │                 │   NATS with URL │
+      │   (with payload │                 │   NATS with URL │
+      │    in envelope) │                 │   (in envelope) │
       └─────────────────┘                 └─────────────────┘
 ```
 
-### 3. Julia Module Architecture
+### 4. Cross-Platform Architecture
+
+```mermaid
+flowchart TD
+    subgraph PythonMicropython
+        Py[Python/Micropython]
+        PySmartSend[smartsend]
+        PySmartReceive[smartreceive]
+    end
+
+    subgraph JavaScript
+        JS[JavaScript]
+        JSSmartSend[smartsend]
+        JSSmartReceive[smartreceive]
+    end
+
+    subgraph Julia
+        Julia[Julia]
+        JuliaSmartSend[smartsend]
+        JuliaSmartReceive[smartreceive]
+    end
+
+    subgraph NATS
+        NATSServer[NATS Server]
+    end
+
+    PySmartSend --> NATSServer
+    JSSmartSend --> NATSServer
+    JuliaSmartSend --> NATSServer
+    NATSServer --> PySmartReceive
+    NATSServer --> JSSmartReceive
+    NATSServer --> JuliaSmartReceive
+
+    style PythonMicropython fill:#e1f5fe
+    style JavaScript fill:#f3e5f5
+    style Julia fill:#e8f5e9
+```
+
+### 5. Python/Micropython Module Architecture
 
 ```mermaid
 graph TD
-    subgraph JuliaModule
-        SmartSendJulia[SmartSend Julia]
+    subgraph PyModule
+        PySmartSend[smartsend]
         SizeCheck[Size Check]
         DirectPath[Direct Path]
         LinkPath[Link Path]
         HTTPClient[HTTP Client]
     end
 
-    SmartSendJulia --> SizeCheck
+    PySmartSend --> SizeCheck
+    SizeCheck -->|< 1MB| DirectPath
+    SizeCheck -->|>= 1MB| LinkPath
+    LinkPath --> HTTPClient
+
+    style PyModule fill:#b3e5fc
+```
+
+### 6. Julia Module Architecture
+
+```mermaid
+graph TD
+    subgraph JuliaModule
+        JuliaSmartSend[smartsend]
+        SizeCheck[Size Check]
+        DirectPath[Direct Path]
+        LinkPath[Link Path]
+        HTTPClient[HTTP Client]
+    end
+
+    JuliaSmartSend --> SizeCheck
     SizeCheck -->|< 1MB| DirectPath
     SizeCheck -->|>= 1MB| LinkPath
     LinkPath --> HTTPClient
@@ -100,19 +349,19 @@ graph TD
     style JuliaModule fill:#c5e1a5
 ```
 
-### 4. JavaScript Module Architecture
+### 7. JavaScript Module Architecture
 
 ```mermaid
 graph TD
     subgraph JSModule
-        SmartSendJS[SmartSend JS]
-        SmartReceiveJS[SmartReceive JS]
+        JSSmartSend[smartsend]
+        JSSmartReceive[smartreceive]
         JetStreamConsumer[JetStream Pull Consumer]
         ApacheArrow[Apache Arrow]
     end
 
-    SmartSendJS --> NATS
-    SmartReceiveJS --> JetStreamConsumer
+    JSSmartSend --> NATS
+    JSSmartReceive --> JetStreamConsumer
     JetStreamConsumer --> ApacheArrow
 
     style JSModule fill:#f3e5f5
@@ -129,74 +378,266 @@ graph TD
 - `HTTP.jl` - HTTP client for file server
 - `Dates.jl` - Timestamps for logging
 
-#### SmartSend Function
+#### smartsend Function
 
 ```julia
-function SmartSend(
+function smartsend(
   subject::String,
-    data::Any,
-    type::String = "json";
-    nats_url::String = "nats://localhost:4222",
-    fileserver_url::String = "http://localhost:8080/upload",
-    size_threshold::Int = 1_000_000  # 1MB
+  data::AbstractArray{Tuple{String, Any, String}, 1};  # List of (dataname, data, type) tuples
+  broker_url::String = DEFAULT_BROKER_URL,  # NATS server URL
+  fileserver_url = DEFAULT_FILESERVER_URL,
+  fileserver_upload_handler::Function = plik_oneshot_upload,
+  size_threshold::Int = DEFAULT_SIZE_THRESHOLD,
+  correlation_id::Union{String, Nothing} = nothing,
+  msg_purpose::String = "chat",
+  sender_name::String = "NATSBridge",
+  receiver_name::String = "",
+  receiver_id::String = "",
+  reply_to::String = "",
+  reply_to_msg_id::String = "",
+  is_publish::Bool = true   # Whether to automatically publish to NATS
 )
 ```
 
-**Flow:**
-1. Serialize data to Arrow IPC stream (if table)
-2. Check payload size
-3. If < threshold: publish directly to NATS with Base64-encoded payload
-4. If >= threshold: upload to HTTP server, publish NATS with URL
+**Return Value:**
+- Returns a tuple `(env, env_json_str)` where:
+  - `env::msg_envelope_v1` - The envelope object containing all metadata and payloads
+  - `env_json_str::String` - JSON string representation of the envelope for publishing
 
-#### SmartReceive Handler
+**Options:**
+- `is_publish::Bool = true` - When `true` (default), the message is automatically published to NATS. When `false`, the function returns the envelope and JSON string without publishing, allowing manual publishing via NATS request-reply pattern.
+
+The envelope object can be accessed directly for programmatic use, while the JSON string can be published directly to NATS using the request-reply pattern.
+
+**Input Format:**
+- `data::AbstractArray{Tuple{String, Any, String}}` - **Must be a list of (dataname, data, type) tuples**: `[("dataname1", data1, "type1"), ("dataname2", data2, "type2"), ...]`
+- Even for single payloads: `[(dataname1, data1, "type1")]`
+- Each payload can have a different type, enabling mixed-content messages
+
+**Flow:**
+1. Iterate through the list of `(dataname, data, type)` tuples
+2. For each payload: extract the type from the tuple and serialize accordingly
+3. Check payload size
+4. If < threshold: publish directly to NATS with Base64-encoded payload
+5. If >= threshold: upload to HTTP server, publish NATS with URL
+
+#### smartreceive Handler
 
 ```julia
-function SmartReceive(msg::NATS.Message)
+function smartreceive(
+    msg::NATS.Msg;
+    fileserver_download_handler::Function = _fetch_with_backoff,
+    max_retries::Int = 5,
+    base_delay::Int = 100,
+    max_delay::Int = 5000
+)
     # Parse envelope
-    # Check transport type
+    # Iterate through all payloads
+    # For each payload: check transport type
     #   If direct: decode Base64 payload
-    # If link: fetch from URL with exponential backoff
-    # Deserialize Arrow IPC to DataFrame
+    #   If link: fetch from URL with exponential backoff using fileserver_download_handler
+    # Deserialize payload based on type
+    # Return envelope dictionary with all metadata and deserialized payloads
 end
 ```
 
+**Output Format:**
+- Returns a dictionary (key-value map) containing all envelope fields:
+  - `correlation_id`, `msg_id`, `timestamp`, `send_to`, `msg_purpose`, `sender_name`, `sender_id`, `receiver_name`, `receiver_id`, `reply_to`, `reply_to_msg_id`, `broker_url`
+  - `metadata` - Message-level metadata dictionary
+  - `payloads` - List of dictionaries, each containing deserialized payload data
+
+**Process Flow:**
+1. Parse the JSON envelope to extract all fields
+2. Iterate through each payload in `payloads`
+3. For each payload:
+   - Determine transport type (`direct` or `link`)
+   - If `direct`: decode Base64 data from the message
+   - If `link`: fetch data from URL using exponential backoff (via `fileserver_download_handler`)
+   - Deserialize based on payload type (`dictionary`, `table`, `binary`, etc.)
+4. Return envelope dictionary with `payloads` field containing list of `(dataname, data, type)` tuples
+
+**Note:** The `fileserver_download_handler` receives `(url::String, max_retries::Int, base_delay::Int, max_delay::Int, correlation_id::String)` and returns `Vector{UInt8}`.
+
 ### JavaScript Implementation
 
 #### Dependencies
 - `nats.js` - Core NATS functionality
 - `apache-arrow` - Arrow IPC serialization
-- `uuid` - Correlation ID generation
+- `uuid` - Correlation ID and message ID generation
+- `base64-arraybuffer` - Base64 encoding/decoding
+- `node-fetch` or `fetch` - HTTP client for file server
 
-#### SmartSend Function
+#### smartsend Function
 
 ```javascript
-async function SmartSend(subject, data, type = 'json', options = {})
+async function smartsend(
+  subject,
+  data,  // List of (dataname, data, type) tuples: [(dataname1, data1, type1), ...]
+  options = {}
+)
 ```
 
-**Flow:**
-1. Serialize data to Arrow IPC buffer (if table)
-2. Check payload size
-3. If < threshold: publish directly to NATS
-4. If >= threshold: upload to HTTP server, publish NATS with URL
+**Options:**
+- `broker_url` (String) - NATS server URL (default: `"nats://localhost:4222"`)
+- `fileserver_url` (String) - Base URL of the file server (default: `"http://localhost:8080"`)
+- `size_threshold` (Number) - Threshold in bytes for transport selection (default: `1048576` = 1MB)
+- `correlation_id` (String) - Optional correlation ID for tracing
+- `msg_purpose` (String) - Purpose of the message (default: `"chat"`)
+- `sender_name` (String) - Sender name (default: `"NATSBridge"`)
+- `receiver_name` (String) - Message receiver name (default: `""`)
+- `receiver_id` (String) - Message receiver ID (default: `""`)
+- `reply_to` (String) - Topic to reply to (default: `""`)
+- `reply_to_msg_id` (String) - Message ID this message is replying to (default: `""`)
+- `fileserver_upload_handler` (Function) - Custom upload handler function
 
-#### SmartReceive Handler
+**Return Value:**
+- Returns a Promise that resolves to an object containing:
+  - `env` - The envelope object containing all metadata and payloads
+  - `env_json_str` - JSON string representation of the envelope for publishing
+  - `published` - Boolean indicating whether the message was automatically published to NATS
+
+**Input Format:**
+- `data` - **Must be a list of (dataname, data, type) tuples**: `[(dataname1, data1, "type1"), (dataname2, data2, "type2"), ...]`
+- Even for single payloads: `[(dataname1, data1, "type1")]`
+- Each payload can have a different type, enabling mixed-content messages
+- Supported types: `"text"`, `"dictionary"`, `"table"`, `"image"`, `"audio"`, `"video"`, `"binary"`
+
+**Flow:**
+1. Generate correlation ID and message ID if not provided
+2. Iterate through the list of `(dataname, data, type)` tuples
+3. For each payload:
+   - Serialize based on payload type
+   - Check payload size
+   - If < threshold: Base64 encode and include in envelope
+   - If >= threshold: Upload to HTTP server, store URL in envelope
+4. Publish the JSON envelope to NATS
+5. Return envelope object and JSON string
+
+#### smartreceive Handler
 
 ```javascript
-async function SmartReceive(msg, options = {})
+async function smartreceive(msg, options = {})
 ```
 
+**Options:**
+- `fileserver_download_handler` (Function) - Custom download handler function
+- `max_retries` (Number) - Maximum retry attempts for fetching URL (default: `5`)
+- `base_delay` (Number) - Initial delay for exponential backoff in ms (default: `100`)
+- `max_delay` (Number) - Maximum delay for exponential backoff in ms (default: `5000`)
+- `correlation_id` (String) - Optional correlation ID for tracing
+
+**Output Format:**
+- Returns a Promise that resolves to an object containing all envelope fields:
+  - `correlation_id`, `msg_id`, `timestamp`, `send_to`, `msg_purpose`, `sender_name`, `sender_id`, `receiver_name`, `receiver_id`, `reply_to`, `reply_to_msg_id`, `broker_url`
+  - `metadata` - Message-level metadata dictionary
+  - `payloads` - List of dictionaries, each containing deserialized payload data with keys: `dataname`, `data`, `payload_type`
+
+**Process Flow:**
+1. Parse the JSON envelope to extract all fields
+2. Iterate through each payload in `payloads` array
+3. For each payload:
+   - Determine transport type (`direct` or `link`)
+   - If `direct`: Base64 decode the data from the message
+   - If `link`: Fetch data from URL using exponential backoff (via `fileserver_download_handler`)
+   - Deserialize based on payload type (`dictionary`, `table`, `binary`, etc.)
+4. Return envelope object with `payloads` field containing list of `(dataname, data, type)` tuples
+
+**Note:** The `fileserver_download_handler` receives `(url, max_retries, base_delay, max_delay, correlation_id)` and returns `ArrayBuffer` or `Uint8Array`.
+
+### Python/Micropython Implementation
+
+#### Dependencies
+- `nats-python` - Core NATS functionality
+- `pyarrow` - Arrow IPC serialization
+- `uuid` - Correlation ID and message ID generation
+- `base64` - Base64 encoding/decoding
+- `requests` or `aiohttp` - HTTP client for file server
+
+#### smartsend Function
+
+```python
+async def smartsend(
+    subject: str,
+    data: List[Tuple[str, Any, str]],  # List of (dataname, data, type) tuples
+    options: Dict = {}
+)
+```
+
+**Options:**
+- `broker_url` (str) - NATS server URL (default: `"nats://localhost:4222"`)
+- `fileserver_url` (str) - Base URL of the file server (default: `"http://localhost:8080"`)
+- `size_threshold` (int) - Threshold in bytes for transport selection (default: `1048576` = 1MB)
+- `correlation_id` (str) - Optional correlation ID for tracing
+- `msg_purpose` (str) - Purpose of the message (default: `"chat"`)
+- `sender_name` (str) - Sender name (default: `"NATSBridge"`)
+- `receiver_name` (str) - Message receiver name (default: `""`)
+- `receiver_id` (str) - Message receiver ID (default: `""`)
+- `reply_to` (str) - Topic to reply to (default: `""`)
+- `reply_to_msg_id` (str) - Message ID this message is replying to (default: `""`)
+- `fileserver_upload_handler` (Callable) - Custom upload handler function
+
+**Return Value:**
+- Returns a tuple `(env, env_json_str)` where:
+  - `env` - The envelope dictionary containing all metadata and payloads
+  - `env_json_str` - JSON string representation of the envelope for publishing
+
+**Input Format:**
+- `data` - **Must be a list of (dataname, data, type) tuples**: `[(dataname1, data1, "type1"), (dataname2, data2, "type2"), ...]`
+- Even for single payloads: `[(dataname1, data1, "type1")]`
+- Each payload can have a different type, enabling mixed-content messages
+- Supported types: `"text"`, `"dictionary"`, `"table"`, `"image"`, `"audio"`, `"video"`, `"binary"`
+
 **Flow:**
-1. Parse envelope
-2. Check transport type
-3. If direct: decode Base64 payload
-4. If link: fetch with exponential backoff
-5. Deserialize Arrow IPC with zero-copy
+1. Generate correlation ID and message ID if not provided
+2. Iterate through the list of `(dataname, data, type)` tuples
+3. For each payload:
+   - Serialize based on payload type
+   - Check payload size
+   - If < threshold: Base64 encode and include in envelope
+   - If >= threshold: Upload to HTTP server, store URL in envelope
+4. Publish the JSON envelope to NATS
+5. Return envelope dictionary and JSON string
+
+#### smartreceive Handler
+
+```python
+async def smartreceive(
+    msg: NATS.Message,
+    options: Dict = {}
+)
+```
+
+**Options:**
+- `fileserver_download_handler` (Callable) - Custom download handler function
+- `max_retries` (int) - Maximum retry attempts for fetching URL (default: `5`)
+- `base_delay` (int) - Initial delay for exponential backoff in ms (default: `100`)
+- `max_delay` (int) - Maximum delay for exponential backoff in ms (default: `5000`)
+- `correlation_id` (str) - Optional correlation ID for tracing
+
+**Output Format:**
+- Returns a dictionary containing all envelope fields:
+  - `correlation_id`, `msg_id`, `timestamp`, `send_to`, `msg_purpose`, `sender_name`, `sender_id`, `receiver_name`, `receiver_id`, `reply_to`, `reply_to_msg_id`, `broker_url`
+  - `metadata` - Message-level metadata dictionary
+  - `payloads` - List of tuples, each containing `(dataname, data, payload_type)` with deserialized payload data
+
+**Process Flow:**
+1. Parse the JSON envelope to extract all fields
+2. Iterate through each payload in `payloads` list
+3. For each payload:
+   - Determine transport type (`direct` or `link`)
+   - If `direct`: Base64 decode the data from the message
+   - If `link`: Fetch data from URL using exponential backoff (via `fileserver_download_handler`)
+   - Deserialize based on payload type (`dictionary`, `table`, `binary`, etc.)
+4. Return envelope dictionary with `payloads` field containing list of `(dataname, data, type)` tuples
+
+**Note:** The `fileserver_download_handler` receives `(url: str, max_retries: int, base_delay: int, max_delay: int, correlation_id: str)` and returns `bytes`.
 
 ## Scenario Implementations
 
-### Scenario 1: Command & Control (Small JSON)
+### Scenario 1: Command & Control (Small Dictionary)
 
-**Julia (Receiver):**
+**Julia (Sender/Receiver):**
 ```julia
 # Subscribe to control subject
 # Parse JSON envelope
@@ -204,15 +645,21 @@ async function SmartReceive(msg, options = {})
 # Send acknowledgment
 ```
 
-**JavaScript (Sender):**
+**JavaScript (Sender/Receiver):**
 ```javascript
-// Create small JSON config
-// Send via SmartSend with type="json"
+// Create small dictionary config
+// Send via smartsend with type="dictionary"
+```
+
+**Python/Micropython (Sender/Receiver):**
+```python
+# Create small dictionary config
+# Send via smartsend with type="dictionary"
 ```
 
 ### Scenario 2: Deep Dive Analysis (Large Arrow Table)
 
-**Julia (Sender):**
+**Julia (Sender/Receiver):**
 ```julia
 # Create large DataFrame
 # Convert to Arrow IPC stream
@@ -221,7 +668,7 @@ async function SmartReceive(msg, options = {})
 # Publish NATS with URL
 ```
 
-**JavaScript (Receiver):**
+**JavaScript (Sender/Receiver):**
 ```javascript
 // Receive NATS message with URL
 // Fetch data from HTTP server
@@ -229,37 +676,156 @@ async function SmartReceive(msg, options = {})
 // Load into Perspective.js or D3
 ```
 
+**Python/Micropython (Sender/Receiver):**
+```python
+# Create large DataFrame
+# Convert to Arrow IPC stream
+# Check size (> 1MB)
+# Upload to HTTP server
+# Publish NATS with URL
+```
+
 ### Scenario 3: Live Audio Processing
 
-**JavaScript (Sender):**
+**JavaScript (Sender/Receiver):**
 ```javascript
 // Capture audio chunk
 // Send as binary with metadata headers
-// Use SmartSend with type="audio"
+// Use smartsend with type="audio"
 ```
 
-**Julia (Receiver):**
+**Julia (Sender/Receiver):**
 ```julia
-// Receive audio data
-// Perform FFT or AI transcription
-// Send results back (JSON + Arrow table)
+# Receive audio data
+# Perform FFT or AI transcription
+# Send results back (JSON + Arrow table)
+```
+
+**Python/Micropython (Sender/Receiver):**
+```python
+# Capture audio chunk
+# Send as binary with metadata headers
+# Use smartsend with type="audio"
 ```
 
 ### Scenario 4: Catch-Up (JetStream)
 
-**Julia (Producer):**
+**Julia (Producer/Consumer):**
 ```julia
 # Publish to JetStream
 # Include metadata for temporal tracking
 ```
 
-**JavaScript (Consumer):**
+**JavaScript (Producer/Consumer):**
 ```javascript
 // Connect to JetStream
 // Request replay from last 10 minutes
 // Process historical and real-time messages
 ```
 
+**Python/Micropython (Producer/Consumer):**
+```python
+# Publish to JetStream
+# Include metadata for temporal tracking
+```
+
+### Scenario 5: Selection (Low Bandwidth)
+
+**Focus:** Small Arrow tables, cross-platform communication. The Action: Any platform wants to send a small DataFrame to show on any receiving application for the user to choose.
+
+**Julia (Sender/Receiver):**
+```julia
+# Create small DataFrame (e.g., 50KB - 500KB)
+# Convert to Arrow IPC stream
+# Check payload size (< 1MB threshold)
+# Publish directly to NATS with Base64-encoded payload
+# Include metadata for dashboard selection context
+```
+
+**JavaScript (Sender/Receiver):**
+```javascript
+// Receive NATS message with direct transport
+// Decode Base64 payload
+// Parse Arrow IPC with zero-copy
+// Load into selection UI component (e.g., dropdown, table)
+// User makes selection
+// Send selection back to Julia
+```
+
+**Python/Micropython (Sender/Receiver):**
+```python
+# Create small DataFrame (e.g., 50KB - 500KB)
+# Convert to Arrow IPC stream
+# Check payload size (< 1MB threshold)
+# Publish directly to NATS with Base64-encoded payload
+# Include metadata for dashboard selection context
+```
+
+**Use Case:** Any server generates a list of available options (e.g., file selections, configuration presets) as a small DataFrame and sends to any receiving application for user selection. The selection is then sent back to the sender for processing.
+
+### Scenario 6: Chat System
+
+**Focus:** Every conversational message is composed of any number and any combination of components, spanning the full spectrum from small to large. This includes text, images, audio, video, tables, and files—specifically accommodating everything from brief snippets to high-resolution images, large audio files, extensive tables, and massive documents. Support for claim-check delivery and full bi-directional messaging across all platforms.
+
+**Multi-Payload Support:** The system supports mixed-payload messages where a single message can contain multiple payloads with different transport strategies. The `smartreceive` function iterates through all payloads in the envelope and processes each according to its transport type.
+
+**Julia (Sender/Receiver):**
+```julia
+# Build chat message with mixed payloads:
+# - Text: direct transport (Base64)
+# - Small images: direct transport (Base64)
+# - Large images: link transport (HTTP URL)
+# - Audio/video: link transport (HTTP URL)
+# - Tables: direct or link depending on size
+# - Files: link transport (HTTP URL)
+# 
+# Each payload uses appropriate transport strategy:
+# - Size < 1MB → direct (NATS + Base64)
+# - Size >= 1MB → link (HTTP upload + NATS URL)
+# 
+# Include claim-check metadata for delivery tracking
+# Support bidirectional messaging with replyTo fields
+```
+
+**JavaScript (Sender/Receiver):**
+```javascript
+// Build chat message with mixed content:
+// - User input text: direct transport
+// - Selected image: check size, use appropriate transport
+// - Audio recording: link transport for large files
+// - File attachment: link transport
+// 
+// Parse received message:
+// - Direct payloads: decode Base64
+// - Link payloads: fetch from HTTP with exponential backoff
+// - Deserialize all payloads appropriately
+// 
+// Render mixed content in chat interface
+// Support bidirectional reply with claim-check delivery confirmation
+```
+
+**Python/Micropython (Sender/Receiver):**
+```python
+# Build chat message with mixed payloads:
+# - Text: direct transport (Base64)
+# - Small images: direct transport (Base64)
+# - Large images: link transport (HTTP URL)
+# - Audio/video: link transport (HTTP URL)
+# - Tables: direct or link depending on size
+# - Files: link transport (HTTP URL)
+# 
+# Each payload uses appropriate transport strategy:
+# - Size < 1MB → direct (NATS + Base64)
+# - Size >= 1MB → link (HTTP upload + NATS URL)
+# 
+# Include claim-check metadata for delivery tracking
+# Support bidirectional messaging with replyTo fields
+```
+
+**Use Case:** Full-featured chat system supporting rich media. User can send text, small images directly, or upload large files that get uploaded to HTTP server and referenced via URLs. Claim-check pattern ensures reliable delivery tracking for all message components across all platforms.
+
+**Implementation Note:** The `smartreceive` function iterates through all payloads in the envelope and processes each according to its transport type. See the standard API format in Section 1: `msgEnvelope_v1` supports `AbstractArray{msgPayload_v1}` for multiple payloads.
+
 ## Performance Considerations
 
 ### Zero-Copy Reading
@@ -280,8 +846,8 @@ async function SmartReceive(msg, options = {})
 ## Testing Strategy
 
 ### Unit Tests
-- Test SmartSend with various payload sizes
-- Test SmartReceive with direct and link transport
+- Test smartsend with various payload sizes
+- Test smartreceive with direct and link transport
 - Test Arrow IPC serialization/deserialization
 
 ### Integration Tests

docs/implementation.md

@@ -0,0 +1,952 @@
+# Implementation Guide: Bi-Directional Data Bridge
+
+## Overview
+
+This document describes the implementation of the high-performance, bi-directional data bridge between **Julia**, **JavaScript**, and **Python/Micropython** applications using NATS (Core & JetStream), implementing the Claim-Check pattern for large payloads.
+
+The system enables seamless communication across all three platforms:
+- **Julia ↔ JavaScript** bi-directional messaging
+- **JavaScript ↔ Python/Micropython** bi-directional messaging
+- **Julia ↔ Python/Micropython** bi-directional messaging (via JSON serialization)
+
+### Implementation Files
+
+NATSBridge is implemented in three languages, each providing the same API:
+
+| Language | Implementation File | Description |
+|----------|---------------------|-------------|
+| **Julia** | [`src/NATSBridge.jl`](../src/NATSBridge.jl) | Full Julia implementation with Arrow IPC support |
+| **JavaScript** | [`src/NATSBridge.js`](../src/NATSBridge.js) | JavaScript implementation for Node.js and browsers |
+| **Python/Micropython** | [`src/nats_bridge.py`](../src/nats_bridge.py) | Python implementation for desktop and microcontrollers |
+
+### File Server Handler Architecture
+
+The system uses **handler functions** to abstract file server operations, allowing support for different file server implementations (e.g., Plik, AWS S3, custom HTTP server).
+
+**Handler Function Signatures:**
+
+```julia
+# Upload handler - uploads data to file server and returns URL
+# The handler is passed to smartsend as fileserver_upload_handler parameter
+# It receives: (file_server_url::String, dataname::String, data::Vector{UInt8})
+# Returns: Dict{String, Any} with keys: "status", "uploadid", "fileid", "url"
+fileserver_upload_handler(file_server_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
+
+# Download handler - fetches data from file server URL with exponential backoff
+# The handler is passed to smartreceive as fileserver_download_handler parameter
+# It receives: (url::String, max_retries::Int, base_delay::Int, max_delay::Int, correlation_id::String)
+# Returns: Vector{UInt8} (the downloaded data)
+fileserver_download_handler(url::String, max_retries::Int, base_delay::Int, max_delay::Int, correlation_id::String)::Vector{UInt8}
+```
+
+This design allows the system to support multiple file server backends without changing the core messaging logic.
+
+### Multi-Payload Support (Standard API)
+
+The system uses a **standardized list-of-tuples format** for all payload operations. **Even when sending a single payload, the user must wrap it in a list.**
+
+**API Standard:**
+```julia
+# Input format for smartsend (always a list of tuples with type info)
+[(dataname1, data1, type1), (dataname2, data2, type2), ...]
+
+# Output format for smartreceive (returns a dictionary with payloads field containing list of tuples)
+# Returns: Dict with envelope metadata and payloads field containing Vector{Tuple{String, Any, String}}
+# {
+#   "correlation_id": "...",
+#   "msg_id": "...",
+#   "timestamp": "...",
+#   "send_to": "...",
+#   "msg_purpose": "...",
+#   "sender_name": "...",
+#   "sender_id": "...",
+#   "receiver_name": "...",
+#   "receiver_id": "...",
+#   "reply_to": "...",
+#   "reply_to_msg_id": "...",
+#   "broker_url": "...",
+#   "metadata": {...},
+#   "payloads": [(dataname1, data1, type1), (dataname2, data2, type2), ...]
+# }
+```
+
+**Supported Types:**
+- `"text"` - Plain text
+- `"dictionary"` - JSON-serializable dictionaries (Dict, NamedTuple)
+- `"table"` - Tabular data (DataFrame, array of structs)
+- `"image"` - Image data (Bitmap, PNG/JPG bytes)
+- `"audio"` - Audio data (WAV, MP3 bytes)
+- `"video"` - Video data (MP4, AVI bytes)
+- `"binary"` - Generic binary data (Vector{UInt8})
+
+This design allows per-payload type specification, enabling **mixed-content messages** where different payloads can use different serialization formats in a single message.
+
+**Examples:**
+```julia
+# Single payload - still wrapped in a list
+smartsend(
+    "/test",
+    [("dataname1", data1, "dictionary")],  # List with one tuple (data, type)
+    broker_url="nats://localhost:4222",
+    fileserver_upload_handler=plik_oneshot_upload
+)
+
+# Multiple payloads in one message with different types
+smartsend(
+    "/test",
+    [("dataname1", data1, "dictionary"), ("dataname2", data2, "table")],
+    broker_url="nats://localhost:4222",
+    fileserver_upload_handler=plik_oneshot_upload
+)
+
+# Mixed content (e.g., chat with text, image, audio)
+smartsend(
+    "/chat",
+    [
+        ("message_text", "Hello!", "text"),
+        ("user_image", image_data, "image"),
+        ("audio_clip", audio_data, "audio")
+    ],
+    broker_url="nats://localhost:4222"
+)
+
+# Receive returns a dictionary envelope with all metadata and deserialized payloads
+env = smartreceive(msg; fileserver_download_handler=_fetch_with_backoff, max_retries=5, base_delay=100, max_delay=5000)
+# env["payloads"] = [("dataname1", data1, type1), ("dataname2", data2, type2), ...]
+# env["correlation_id"], env["msg_id"], etc.
+# env is a dictionary containing envelope metadata and payloads field
+```
+
+## Cross-Platform Interoperability
+
+NATSBridge is designed for seamless communication between Julia, JavaScript, and Python/Micropython applications. All three implementations share the same interface and data format, ensuring compatibility across platforms.
+
+### Platform-Specific Features
+
+| Feature | Julia | JavaScript | Python/Micropython |
+|---------|-------|------------|-------------------|
+| Direct NATS transport | ✅ | ✅ | ✅ |
+| HTTP file server (Claim-Check) | ✅ | ✅ | ✅ |
+| Arrow IPC tables | ✅ | ✅ | ✅ |
+| Base64 encoding | ✅ | ✅ | ✅ |
+| Exponential backoff | ✅ | ✅ | ✅ |
+| Correlation ID tracking | ✅ | ✅ | ✅ |
+| Reply-to support | ✅ | ✅ | ✅ |
+
+### Data Type Mapping
+
+| Type | Julia | JavaScript | Python/Micropython |
+|------|-------|------------|-------------------|
+| `text` | `String` | `String` | `str` |
+| `dictionary` | `Dict` | `Object` | `dict` |
+| `table` | `DataFrame` | `Array<Object>` | `DataFrame` / `list` |
+| `image` | `Vector{UInt8}` | `ArrayBuffer/Uint8Array` | `bytes` |
+| `audio` | `Vector{UInt8}` | `ArrayBuffer/Uint8Array` | `bytes` |
+| `video` | `Vector{UInt8}` | `ArrayBuffer/Uint8Array` | `bytes` |
+| `binary` | `Vector{UInt8}` | `ArrayBuffer/Uint8Array` | `bytes` |
+
+### Example: Julia ↔ Python ↔ JavaScript
+
+```julia
+# Julia sender
+using NATSBridge
+data = [("message", "Hello from Julia!", "text")]
+smartsend("/cross_platform", data, broker_url="nats://localhost:4222")
+```
+
+```javascript
+// JavaScript receiver
+const { smartreceive } = require('./src/NATSBridge');
+const env = await smartreceive(msg);
+// env.payloads[0].data === "Hello from Julia!"
+```
+
+```python
+# Python sender
+from nats_bridge import smartsend
+data = [("response", "Hello from Python!", "text")]
+smartsend("/cross_platform", data, nats_url="nats://localhost:4222")
+```
+
+All three platforms can communicate seamlessly using the same NATS subjects and data format.
+
+## Architecture
+
+All three implementations (Julia, JavaScript, Python/Micropython) follow the same Claim-Check pattern:
+
+```
+┌─────────────────────────────────────────────────────────────────────────┐
+│                         SmartSend Function                              │
+└─────────────────────────────────────────────────────────────────────────┘
+                              │
+                              ▼
+┌─────────────────────────────────────────────────────────────────────────┐
+│  Is payload size < 1MB?                                                 │
+└─────────────────────────────────────────────────────────────────────────┘
+                              │
+            ┌─────────────────┴─────────────────┐
+            ▼                                   ▼
+      ┌─────────────────┐                 ┌─────────────────┐
+      │  Direct Path    │                 │  Link Path      │
+      │  (< 1MB)        │                 │  (> 1MB)        │
+      │                 │                 │                 │
+      │ • Serialize to  │                 │ • Serialize to  │
+      │   Buffer        │                 │   Buffer        │
+      │ • Base64 encode │                 │ • Upload to     │
+      │ • Publish to    │                 │   HTTP Server   │
+      │   NATS          │                 │ • Publish to    │
+      │                 │                 │   NATS with URL │
+      └─────────────────┘                 └─────────────────┘
+```
+
+## smartsend Return Value
+
+The `smartsend` function now returns a tuple containing both the envelope object and the JSON string representation:
+
+```julia
+env, env_json_str = smartsend(...)
+# env::msg_envelope_v1    - The envelope object with all metadata and payloads
+# env_json_str::String    - JSON string for publishing to NATS
+```
+
+**Options:**
+- `is_publish::Bool = true` - When `true` (default), the message is automatically published to NATS. When `false`, the function returns the envelope and JSON string without publishing, allowing manual publishing via NATS request-reply pattern.
+
+This enables two use cases:
+1. **Programmatic envelope access**: Access envelope fields directly via the `env` object
+2. **Direct JSON publishing**: Publish the JSON string directly using NATS request-reply pattern
+
+### Julia Module: [`src/NATSBridge.jl`](../src/NATSBridge.jl)
+
+The Julia implementation provides:
+
+- **[`msg_envelope_v1`](src/NATSBridge.jl)**: Struct for the unified JSON envelope
+- **[`msg_payload_v1`](src/NATSBridge.jl)**: Struct for individual payload representation
+- **[`smartsend()`](src/NATSBridge.jl)**: Handles transport selection based on payload size
+- **[`smartreceive()`](src/NATSBridge.jl)**: Handles both direct and link transport
+
+### JavaScript Module: [`src/NATSBridge.js`](../src/NATSBridge.js)
+
+The JavaScript implementation provides:
+
+- **`MessageEnvelope` class**: For the unified JSON envelope
+- **`MessagePayload` class**: For individual payload representation
+- **[`smartsend()`](src/NATSBridge.js)**: Handles transport selection based on payload size
+- **[`smartreceive()`](src/NATSBridge.js)**: Handles both direct and link transport
+
+### Python/Micropython Module: [`src/nats_bridge.py`](../src/nats_bridge.py)
+
+The Python/Micropython implementation provides:
+
+- **`MessageEnvelope` class**: For the unified JSON envelope
+- **`MessagePayload` class**: For individual payload representation
+- **[`smartsend()`](src/nats_bridge.py)**: Handles transport selection based on payload size
+- **[`smartreceive()`](src/nats_bridge.py)**: Handles both direct and link transport
+
+## Installation
+
+### Julia Dependencies
+
+```julia
+using Pkg
+Pkg.add("NATS")
+Pkg.add("Arrow")
+Pkg.add("JSON3")
+Pkg.add("HTTP")
+Pkg.add("UUIDs")
+Pkg.add("Dates")
+```
+
+### JavaScript Dependencies
+
+```bash
+npm install nats.js apache-arrow uuid base64-url
+```
+
+### Python/Micropython Dependencies
+
+1. Copy [`src/nats_bridge.py`](../src/nats_bridge.py) to your device
+2. Ensure you have the following dependencies:
+
+   **For Python (desktop):**
+   ```bash
+   pip install nats-py
+   ```
+
+   **For Micropython:**
+   - `urequests` for HTTP requests
+   - `base64` for base64 encoding (built-in)
+   - `json` for JSON handling (built-in)
+   - `socket` for networking (built-in)
+   - `uuid` for UUID generation (built-in)
+
+## Usage Tutorial
+
+### Step 1: Start NATS Server
+
+```bash
+docker run -p 4222:4222 nats:latest
+```
+
+### Step 2: Start HTTP File Server (optional)
+
+```bash
+# Create a directory for file uploads
+mkdir -p /tmp/fileserver
+
+# Use any HTTP server that supports POST for file uploads
+# Example: Python's built-in server
+python3 -m http.server 8080 --directory /tmp/fileserver
+```
+
+### Step 3: Run Test Scenarios
+
+```bash
+# Scenario 1: Command & Control (JavaScript sender)
+node test/scenario1_command_control.js
+
+# Scenario 2: Large Arrow Table (JavaScript sender)
+node test/scenario2_large_table.js
+
+# Scenario 3: Julia-to-Julia communication
+# Run both Julia and JavaScript versions
+julia test/scenario3_julia_to_julia.jl
+node test/scenario3_julia_to_julia.js
+```
+
+## Usage
+
+### Scenario 1: Command & Control (Small Dictionary)
+
+**Focus:** Sending small dictionary configurations across platforms. This is the simplest use case for command and control scenarios.
+
+**Julia (Sender/Receiver):**
+```julia
+using NATSBridge
+
+# Subscribe to control subject
+# Parse JSON envelope
+# Execute simulation with parameters
+# Send acknowledgment
+```
+
+**JavaScript (Sender/Receiver):**
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+// Create small dictionary config
+// Send via smartsend with type="dictionary"
+const config = {
+    step_size: 0.01,
+    iterations: 1000,
+    threshold: 0.5
+};
+
+await smartsend("control", [
+    { dataname: "config", data: config, type: "dictionary" }
+]);
+```
+
+**Python/Micropython (Sender/Receiver):**
+```python
+from nats_bridge import smartsend
+
+# Create small dictionary config
+# Send via smartsend with type="dictionary"
+config = {
+    "step_size": 0.01,
+    "iterations": 1000,
+    "threshold": 0.5
+}
+
+smartsend("control", [("config", config, "dictionary")])
+```
+
+### Basic Multi-Payload Example
+
+#### Python/Micropython (Sender)
+```python
+from nats_bridge import smartsend
+
+# Send multiple payloads in one message (type is required per payload)
+smartsend(
+    "/test",
+    [("dataname1", data1, "dictionary"), ("dataname2", data2, "table")],
+    nats_url="nats://localhost:4222",
+    fileserver_url="http://localhost:8080"
+)
+
+# Even single payload must be wrapped in a list with type
+smartsend("/test", [("single_data", mydata, "dictionary")], nats_url="nats://localhost:4222")
+```
+
+#### Python/Micropython (Receiver)
+```python
+from nats_bridge import smartreceive
+
+# Receive returns a dictionary with envelope metadata and payloads field
+env = smartreceive(msg)
+# env["payloads"] = [(dataname1, data1, "dictionary"), (dataname2, data2, "table"), ...]
+```
+
+#### JavaScript (Sender)
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+// Single payload wrapped in a list
+const config = [{
+    dataname: "config",
+    data: { step_size: 0.01, iterations: 1000 },
+    type: "dictionary"
+}];
+
+await smartsend("control", config, {
+    correlationId: "unique-id"
+});
+
+// Multiple payloads
+const configs = [
+    {
+        dataname: "config1",
+        data: { step_size: 0.01 },
+        type: "dictionary"
+    },
+    {
+        dataname: "config2", 
+        data: { iterations: 1000 },
+        type: "dictionary"
+    }
+];
+
+await smartsend("control", configs);
+```
+
+#### JavaScript (Receiver)
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+
+// Subscribe to messages
+const nc = await connect({ servers: ['nats://localhost:4222'] });
+const sub = nc.subscribe("control");
+
+for await (const msg of sub) {
+    const env = await smartreceive(msg);
+    
+    // Process the payloads from the envelope
+    for (const payload of env.payloads) {
+        const { dataname, data, type } = payload;
+        console.log(`Received ${dataname} of type ${type}`);
+        console.log(`Data: ${JSON.stringify(data)}`);
+    }
+    
+    // Also access envelope metadata
+    console.log(`Correlation ID: ${env.correlation_id}`);
+    console.log(`Message ID: ${env.msg_id}`);
+}
+```
+
+### Scenario 2: Deep Dive Analysis (Large Arrow Table)
+
+#### Julia (Sender)
+```julia
+using Arrow
+using DataFrames
+
+# Create large DataFrame
+df = DataFrame(
+    id = 1:10_000_000,
+    value = rand(10_000_000),
+    category = rand(["A", "B", "C"], 10_000_000)
+)
+
+# Send via smartsend - wrapped in a list (type is part of each tuple)
+env, env_json_str = smartsend("analysis_results", [("table_data", df, "table")], broker_url="nats://localhost:4222")
+# env: msg_envelope_v1 object with all metadata and payloads
+# env_json_str: JSON string representation of the envelope for publishing
+```
+
+#### JavaScript (Receiver)
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+
+const env = await smartreceive(msg);
+
+// Use table data from the payloads field
+// Note: Tables are sent as arrays of objects in JavaScript
+const table = env.payloads;
+```
+
+### Scenario 3: Live Binary Processing
+
+#### Python/Micropython (Sender)
+```python
+from nats_bridge import smartsend
+
+# Binary data wrapped in a list
+binary_data = [
+    ("audio_chunk", binary_buffer, "binary")
+]
+
+smartsend(
+    "binary_input",
+    binary_data,
+    nats_url="nats://localhost:4222",
+    metadata={
+        "sample_rate": 44100,
+        "channels": 1
+    }
+)
+```
+
+#### JavaScript (Sender)
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+// Binary data wrapped in a list
+const binaryData = [{
+    dataname: "audio_chunk",
+    data: binaryBuffer,  // ArrayBuffer or Uint8Array
+    type: "binary"
+}];
+
+await smartsend("binary_input", binaryData, {
+    metadata: {
+        sample_rate: 44100,
+        channels: 1
+    }
+});
+```
+
+#### Python/Micropython (Receiver)
+```python
+from nats_bridge import smartreceive
+
+# Receive binary data
+def process_binary(msg):
+    env = smartreceive(msg)
+    
+    # Process the binary data from env.payloads
+    for dataname, data, type in env["payloads"]:
+        if type == "binary":
+            # data is bytes
+            print(f"Received binary data: {dataname}, size: {len(data)}")
+            # Perform FFT or AI transcription here
+```
+
+#### JavaScript (Receiver)
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+
+// Receive binary data
+function process_binary(msg) {
+    const env = await smartreceive(msg);
+    
+    // Process the binary data from env.payloads
+    for (const payload of env.payloads) {
+        if (payload.type === "binary") {
+            // data is an ArrayBuffer or Uint8Array
+            console.log(`Received binary data: ${payload.dataname}, size: ${payload.data.length}`);
+            // Perform FFT or AI transcription here
+        }
+    }
+}
+```
+
+### Scenario 4: Catch-Up (JetStream)
+
+#### Julia (Producer)
+```julia
+using NATSBridge
+
+function publish_health_status(nats_url)
+    # Send status wrapped in a list (type is part of each tuple)
+    status = Dict("cpu" => rand(), "memory" => rand())
+    smartsend("health", [("status", status, "dictionary")], broker_url=nats_url)
+    sleep(5)  # Every 5 seconds
+end
+```
+
+#### JavaScript (Consumer)
+```javascript
+const { connect } = require('nats');
+const { smartreceive } = require('./src/NATSBridge');
+
+const nc = await connect({ servers: ['nats://localhost:4222'] });
+const js = nc.jetstream();
+
+// Request replay from last 10 minutes
+const consumer = await js.pullSubscribe("health", { 
+    durable_name: "catchup",
+    max_batch: 100,
+    max_ack_wait: 30000
+});
+
+// Process historical and real-time messages
+for await (const msg of consumer) {
+    const env = await smartreceive(msg);
+    // env.payloads contains the list of payloads
+    // Each payload has: dataname, data, type
+    msg.ack();
+}
+```
+
+### Scenario 4: Micropython Device Control
+
+**Focus:** Sending configuration to a Micropython device over NATS. This demonstrates the lightweight nature of the Python implementation suitable for microcontrollers.
+
+**Python/Micropython (Receiver/Device):**
+```python
+from nats_bridge import smartsend, smartreceive
+import json
+
+# Device configuration handler
+def handle_device_config(msg):
+    env = smartreceive(msg)
+    
+    # Process configuration from payloads
+    for dataname, data, type in env["payloads"]:
+        if type == "dictionary":
+            print(f"Received configuration: {data}")
+            # Apply configuration to device
+            if "wifi_ssid" in data:
+                wifi_ssid = data["wifi_ssid"]
+                wifi_password = data["wifi_password"]
+                update_wifi_config(wifi_ssid, wifi_password)
+    
+    # Send confirmation back
+    config = {
+        "status": "configured",
+        "wifi_ssid": "MyNetwork",
+        "ip": get_device_ip()
+    }
+    smartsend(
+        "device/response",
+        [("config", config, "dictionary")],
+        nats_url="nats://localhost:4222",
+        reply_to=env.get("reply_to")
+    )
+```
+
+**JavaScript (Sender/Controller):**
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+// Send configuration to Micropython device
+await smartsend("device/config", [
+    {
+        dataname: "config",
+        data: {
+            wifi_ssid: "MyNetwork",
+            wifi_password: "password123",
+            update_interval: 60,
+            temperature_threshold: 30.0
+        },
+        type: "dictionary"
+    }
+]);
+```
+
+**Use Case:** A controller sends WiFi and operational configuration to a Micropython device (e.g., ESP32). The device receives the configuration, applies it, and sends back a confirmation with its current status.
+
+### Scenario 5: Selection (Low Bandwidth)
+
+**Focus:** Small Arrow tables, Julia to JavaScript. The Action: Julia wants to send a small DataFrame to show on a JavaScript dashboard for the user to choose.
+
+**Julia (Sender):**
+```julia
+using NATSBridge
+using DataFrames
+
+# Create small DataFrame (e.g., 50KB - 500KB)
+options_df = DataFrame(
+    id = 1:10,
+    name = ["Option A", "Option B", "Option C", "Option D", "Option E",
+            "Option F", "Option G", "Option H", "Option I", "Option J"],
+    description = ["Description A", "Description B", "Description C", "Description D", "Description E",
+                   "Description F", "Description G", "Description H", "Description I", "Description J"]
+)
+
+# Convert to Arrow IPC stream
+# Check payload size (< 1MB threshold)
+# Publish directly to NATS with Base64-encoded payload
+# Include metadata for dashboard selection context
+smartsend(
+    "dashboard.selection",
+    [("options_table", options_df, "table")],
+    nats_url="nats://localhost:4222",
+    metadata=Dict("context" => "user_selection")
+)
+```
+
+**JavaScript (Receiver):**
+```javascript
+const { smartreceive, smartsend } = require('./src/NATSBridge');
+
+// Receive NATS message with direct transport
+const env = await smartreceive(msg);
+
+// Decode Base64 payload (for direct transport)
+// For tables, data is in env.payloads
+const table = env.payloads;  // Array of objects
+
+// User makes selection
+const selection = uiComponent.getSelectedOption();
+
+// Send selection back to Julia
+await smartsend("dashboard.response", [
+    { dataname: "selected_option", data: selection, type: "dictionary" }
+]);
+```
+
+**Use Case:** Julia server generates a list of available options (e.g., file selections, configuration presets) as a small DataFrame and sends to JavaScript dashboard for user selection. The selection is then sent back to Julia for processing.
+
+### Scenario 6: Chat System
+
+**Focus:** Every conversational message is composed of any number and any combination of components, spanning the full spectrum from small to large. This includes text, images, audio, video, tables, and files—specifically accommodating everything from brief snippets to high-resolution images, large audio files, extensive tables, and massive documents. Support for claim-check delivery and full bi-directional messaging.
+
+**Multi-Payload Support:** The system supports mixed-payload messages where a single message can contain multiple payloads with different transport strategies. The `smartreceive` function iterates through all payloads in the envelope and processes each according to its transport type.
+
+**Julia (Sender/Receiver):**
+```julia
+using NATSBridge
+using DataFrames
+
+# Build chat message with mixed payloads:
+# - Text: direct transport (Base64)
+# - Small images: direct transport (Base64)
+# - Large images: link transport (HTTP URL)
+# - Audio/video: link transport (HTTP URL)
+# - Tables: direct or link depending on size
+# - Files: link transport (HTTP URL)
+# 
+# Each payload uses appropriate transport strategy:
+# - Size < 1MB → direct (NATS + Base64)
+# - Size >= 1MB → link (HTTP upload + NATS URL)
+# 
+# Include claim-check metadata for delivery tracking
+# Support bidirectional messaging with replyTo fields
+
+# Example: Chat with text, small image, and large file
+chat_message = [
+    ("message_text", "Hello, this is a test message!", "text"),
+    ("user_avatar", image_bytes, "image"),  # Small image, direct transport
+    ("large_document", large_file_bytes, "binary")  # Large file, link transport
+]
+
+smartsend(
+    "chat.room123",
+    chat_message,
+    broker_url="nats://localhost:4222",
+    msg_purpose="chat",
+    reply_to="chat.room123.responses"
+)
+```
+
+**JavaScript (Sender/Receiver):**
+```javascript
+const { smartsend, smartreceive } = require('./src/NATSBridge');
+
+// Build chat message with mixed content:
+// - User input text: direct transport
+// - Selected image: check size, use appropriate transport
+// - Audio recording: link transport for large files
+// - File attachment: link transport
+// 
+// Parse received message:
+// - Direct payloads: decode Base64
+// - Link payloads: fetch from HTTP with exponential backoff
+// - Deserialize all payloads appropriately
+// 
+// Render mixed content in chat interface
+// Support bidirectional reply with claim-check delivery confirmation
+
+// Example: Send chat with mixed content
+const message = [
+    {
+        dataname: "text",
+        data: "Hello from JavaScript!",
+        type: "text"
+    },
+    {
+        dataname: "image",
+        data: selectedImageBuffer,  // Small image (ArrayBuffer or Uint8Array)
+        type: "image"
+    },
+    {
+        dataname: "audio",
+        data: audioUrl,  // Large audio, link transport
+        type: "audio"
+    }
+];
+
+await smartsend("chat.room123", message);
+```
+
+**Use Case:** Full-featured chat system supporting rich media. User can send text, small images directly, or upload large files that get uploaded to HTTP server and referenced via URLs. Claim-check pattern ensures reliable delivery tracking for all message components.
+
+**Implementation Note:** The `smartreceive` function iterates through all payloads in the envelope and processes each according to its transport type. See the standard API format in Section 1: `msg_envelope_v1` supports `Vector{msg_payload_v1}` for multiple payloads.
+
+## Configuration
+
+### Environment Variables
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `NATS_URL` | `nats://localhost:4222` | NATS server URL |
+| `FILESERVER_URL` | `http://localhost:8080` | HTTP file server URL (base URL without `/upload` suffix) |
+| `SIZE_THRESHOLD` | `1_000_000` | Size threshold in bytes (1MB) |
+
+### Message Envelope Schema
+
+```json
+{
+  "correlation_id": "uuid-v4-string",
+  "msg_id": "uuid-v4-string",
+  "timestamp": "2024-01-15T10:30:00Z",
+  
+  "send_to": "topic/subject",
+  "msg_purpose": "ACK | NACK | updateStatus | shutdown | chat",
+  "sender_name": "agent-wine-web-frontend",
+  "sender_id": "uuid4",
+  "receiver_name": "agent-backend",
+  "receiver_id": "uuid4",
+  "reply_to": "topic",
+  "reply_to_msg_id": "uuid4",
+  "broker_url": "nats://localhost:4222",
+  
+  "metadata": {
+    "content_type": "application/octet-stream",
+    "content_length": 123456
+  },
+  
+  "payloads": [
+    {
+      "id": "uuid4",
+      "dataname": "login_image",
+      "payload_type": "image",
+      "transport": "direct",
+      "encoding": "base64",
+      "size": 15433,
+      "data": "base64-encoded-string",
+      "metadata": {
+        "checksum": "sha256_hash"
+      }
+    }
+  ]
+}
+```
+
+## Performance Considerations
+
+### Zero-Copy Reading
+- Use Arrow's memory-mapped file reading
+- Avoid unnecessary data copying during deserialization
+- Use Apache Arrow's native IPC reader
+
+### Exponential Backoff
+- Maximum retry count: 5
+- Base delay: 100ms, max delay: 5000ms
+- Implemented in all three implementations (Julia, JavaScript, Python/Micropython)
+
+### Correlation ID Logging
+- Log correlation_id at every stage
+- Include: send, receive, serialize, deserialize
+- Use structured logging format
+
+## Testing
+
+Run the test scripts for each platform:
+
+### Python/Micropython Tests
+
+```bash
+# Basic functionality test
+python test/test_micropython_basic.py
+```
+
+### JavaScript Tests
+
+```bash
+# Text message exchange
+node test/test_js_to_js_text_sender.js
+node test/test_js_to_js_text_receiver.js
+
+# Dictionary exchange
+node test/test_js_to_js_dict_sender.js
+node test/test_js_to_js_dict_receiver.js
+
+# File transfer (direct transport)
+node test/test_js_to_js_file_sender.js
+node test/test_js_to_js_file_receiver.js
+
+# Mixed payload types
+node test/test_js_to_js_mix_payloads_sender.js
+node test/test_js_to_js_mix_payloads_receiver.js
+
+# Table (Arrow IPC) exchange
+node test/test_js_to_js_table_sender.js
+node test/test_js_to_js_table_receiver.js
+```
+
+### Julia Tests
+
+```bash
+# Text message exchange
+julia test/test_julia_to_julia_text_sender.jl
+julia test/test_julia_to_julia_text_receiver.jl
+
+# Dictionary exchange
+julia test/test_julia_to_julia_dict_sender.jl
+julia test/test_julia_to_julia_dict_receiver.jl
+
+# File transfer
+julia test/test_julia_to_julia_file_sender.jl
+julia test/test_julia_to_julia_file_receiver.jl
+
+# Mixed payload types
+julia test/test_julia_to_julia_mix_payloads_sender.jl
+julia test/test_julia_to_julia_mix_payloads_receiver.jl
+
+# Table exchange
+julia test/test_julia_to_julia_table_sender.jl
+julia test/test_julia_to_julia_table_receiver.jl
+```
+
+### Cross-Platform Tests
+
+```bash
+# Julia ↔ JavaScript communication
+julia test/test_julia_to_julia_text_sender.jl
+node test/test_js_to_js_text_receiver.js
+
+# Python ↔ JavaScript communication
+python test/test_micropython_basic.py
+node test/test_js_to_js_text_receiver.js
+```
+
+## Troubleshooting
+
+### Common Issues
+
+1. **NATS Connection Failed**
+   - **Julia/JavaScript/Python**: Ensure NATS server is running
+   - **Python/Micropython**: Check `nats_url` parameter and network connectivity
+
+2. **HTTP Upload Failed**
+   - Ensure file server is running
+   - Check `fileserver_url` configuration
+   - Verify upload permissions
+   - **Micropython**: Ensure `urequests` is available and network is connected
+
+3. **Arrow IPC Deserialization Error**
+   - Ensure data is properly serialized to Arrow format
+   - Check Arrow version compatibility
+
+4. **Python/Micropython Specific Issues**
+   - **Import Error**: Ensure `nats_bridge.py` is in the correct path
+   - **Memory Error (Micropython)**: Reduce payload size or use link transport for large payloads
+   - **Unicode Error**: Ensure proper encoding when sending text data
+
+## License
+
+MIT

etc.jl

@@ -1,42 +0,0 @@
-
-""" fileServerURL = "http://192.168.88.104:8080"
-filepath = "/home/ton/docker-apps/sendreceive/image/test.zip"
-filename = basename(filepath)
-filebytes = read(filepath)
-
-plik_oneshot_upload - Upload a single file to a plik server using one-shot mode
-
-This function uploads a raw byte array to a plik server in one-shot mode (no upload session).
-It first creates a one-shot upload session by sending a POST request with `{"OneShot": true}`,
-retrieves an upload ID and token, then uploads the file data as multipart form data using the token.
-
-The function handles the entire flow:
-1. Obtains an upload ID and token from the server
-2. Uploads the provided binary data as a file using the `X-UploadToken` header
-3. Returns identifiers and download URL for the uploaded file
-
-# Arguments:
-  - `fileServerURL::String` - Base URL of the plik server (e.g., `"http://192.168.88.104:8080"`)
-  - `filename::String` - Name of the file being uploaded
-  - `data::Vector{UInt8}` - Raw byte data of the file content
-
-# Return:
-  - A named tuple with fields:
-    - `uploadid::String` - ID of the one-shot upload session
-    - `fileid::String` - ID of the uploaded file within the session
-    - `downloadurl::String` - Full URL to download the uploaded file
-
-# Example
-```jldoctest
-using HTTP, JSON
-
-# Example data: "Hello" as bytes
-data = collect("Hello World!" |> collect |> CodeUnits |> collect)
-
-# Upload to local plik server
-result = plik_oneshot_upload("http://192.168.88.104:8080", "hello.txt", data)
-
-# Download URL for the uploaded file
-println(result.downloadurl)
-```
-"""

examples/tutorial.md

@@ -0,0 +1,620 @@
+# NATSBridge Tutorial
+
+A step-by-step guide to get started with NATSBridge - a high-performance, bi-directional data bridge for **Julia**, **JavaScript**, and **Python/Micropython**.
+
+## Table of Contents
+
+1. [Overview](#overview)
+2. [Prerequisites](#prerequisites)
+3. [Installation](#installation)
+4. [Quick Start](#quick-start)
+5. [Basic Examples](#basic-examples)
+6. [Advanced Usage](#advanced-usage)
+7. [Cross-Platform Communication](#cross-platform-communication)
+
+---
+
+## Overview
+
+NATSBridge enables seamless communication between Julia, JavaScript, and Python/Micropython applications through NATS, with automatic transport selection based on payload size:
+
+- **Direct Transport**: Payloads < 1MB are sent directly via NATS (Base64 encoded)
+- **Link Transport**: Payloads >= 1MB are uploaded to an HTTP file server and referenced via URL
+
+### Supported Payload Types
+
+| Type | Description |
+|------|-------------|
+| `text` | Plain text strings |
+| `dictionary` | JSON-serializable dictionaries |
+| `table` | Tabular data (Arrow IPC format) |
+| `image` | Image data (PNG, JPG bytes) |
+| `audio` | Audio data (WAV, MP3 bytes) |
+| `video` | Video data (MP4, AVI bytes) |
+| `binary` | Generic binary data |
+
+---
+
+## Prerequisites
+
+Before you begin, ensure you have:
+
+1. **NATS Server** running (or accessible)
+2. **HTTP File Server** (optional, for large payloads > 1MB)
+3. **One of the supported platforms**: Julia, JavaScript (Node.js), or Python/Micropython
+
+---
+
+## Installation
+
+### Julia
+
+```julia
+using Pkg
+Pkg.add("NATS")
+Pkg.add("Arrow")
+Pkg.add("JSON3")
+Pkg.add("HTTP")
+Pkg.add("UUIDs")
+Pkg.add("Dates")
+```
+
+### JavaScript
+
+```bash
+npm install nats.js apache-arrow uuid base64-url
+```
+
+### Python/Micropython
+
+1. Copy `src/nats_bridge.py` to your device
+2. Install dependencies:
+
+**For Python (desktop):**
+```bash
+pip install nats-py
+```
+
+**For Micropython:**
+- `urequests` for HTTP requests
+- `base64` for base64 encoding (built-in)
+- `json` for JSON handling (built-in)
+
+---
+
+## Quick Start
+
+### Step 1: Start NATS Server
+
+```bash
+docker run -p 4222:4222 nats:latest
+```
+
+### Step 2: Start HTTP File Server (Optional)
+
+```bash
+# Create a directory for file uploads
+mkdir -p /tmp/fileserver
+
+# Use Python's built-in server
+python3 -m http.server 8080 --directory /tmp/fileserver
+```
+
+### Step 3: Send Your First Message
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+# Send a text message (is_publish=True by default)
+data = [("message", "Hello World", "text")]
+env, env_json_str = smartsend("/chat/room1", data, nats_url="nats://localhost:4222")
+print("Message sent!")
+
+# Or use is_publish=False to get envelope and JSON without publishing
+env, env_json_str = smartsend("/chat/room1", data, nats_url="nats://localhost:4222", is_publish=False)
+# env: MessageEnvelope object
+# env_json_str: JSON string for publishing to NATS
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+// Send a text message (isPublish=true by default)
+await smartsend("/chat/room1", [
+    { dataname: "message", data: "Hello World", type: "text" }
+], { natsUrl: "nats://localhost:4222" });
+
+console.log("Message sent!");
+
+// Or use isPublish=false to get envelope and JSON without publishing
+const { env, env_json_str } = await smartsend("/chat/room1", [
+    { dataname: "message", data: "Hello World", type: "text" }
+], { natsUrl: "nats://localhost:4222", isPublish: false });
+// env: MessageEnvelope object
+// env_json_str: JSON string for publishing to NATS
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+# Send a text message
+data = [("message", "Hello World", "text")]
+env, env_json_str = smartsend("/chat/room1", data, nats_url="nats://localhost:4222")
+# env: msgEnvelope_v1 object with all metadata and payloads
+# env_json_str: JSON string representation of the envelope for publishing
+println("Message sent!")
+```
+
+### Step 4: Receive Messages
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartreceive
+
+# Receive and process message
+env = smartreceive(msg)
+for dataname, data, type in env["payloads"]:
+    print(f"Received {dataname}: {data}")
+```
+
+#### JavaScript
+
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+
+// Receive and process message
+const env = await smartreceive(msg);
+for (const payload of env.payloads) {
+    console.log(`Received ${payload.dataname}: ${payload.data}`);
+}
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+# Receive and process message
+env = smartreceive(msg; fileserver_download_handler=_fetch_with_backoff)
+for (dataname, data, type) in env["payloads"]
+    println("Received $dataname: $data")
+end
+```
+
+---
+
+## Basic Examples
+
+### Example 1: Sending a Dictionary
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+# Create configuration dictionary
+config = {
+    "wifi_ssid": "MyNetwork",
+    "wifi_password": "password123",
+    "update_interval": 60
+}
+
+# Send as dictionary type
+data = [("config", config, "dictionary")]
+env, env_json_str = smartsend("/device/config", data, nats_url="nats://localhost:4222")
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+const config = {
+    wifi_ssid: "MyNetwork",
+    wifi_password: "password123",
+    update_interval: 60
+};
+
+const { env, env_json_str } = await smartsend("/device/config", [
+    { dataname: "config", data: config, type: "dictionary" }
+]);
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+config = Dict(
+    "wifi_ssid" => "MyNetwork",
+    "wifi_password" => "password123",
+    "update_interval" => 60
+)
+
+data = [("config", config, "dictionary")]
+env, env_json_str = smartsend("/device/config", data)
+```
+
+### Example 2: Sending Binary Data (Image)
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+# Read image file
+with open("image.png", "rb") as f:
+    image_data = f.read()
+
+# Send as binary type
+data = [("user_image", image_data, "binary")]
+env, env_json_str = smartsend("/chat/image", data, nats_url="nats://localhost:4222")
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+// Read image file (Node.js)
+const fs = require('fs');
+const image_data = fs.readFileSync('image.png');
+
+const { env, env_json_str } = await smartsend("/chat/image", [
+    { dataname: "user_image", data: image_data, type: "binary" }
+]);
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+# Read image file
+image_data = read("image.png")
+
+data = [("user_image", image_data, "binary")]
+env, env_json_str = smartsend("/chat/image", data)
+```
+
+### Example 3: Request-Response Pattern
+
+#### Python/Micropython (Requester)
+
+```python
+from nats_bridge import smartsend
+
+# Send command with reply-to
+data = [("command", {"action": "read_sensor"}, "dictionary")]
+env, env_json_str = smartsend(
+    "/device/command",
+    data,
+    nats_url="nats://localhost:4222",
+    reply_to="/device/response",
+    reply_to_msg_id="cmd-001"
+)
+# env: msgEnvelope_v1 object
+# env_json_str: JSON string for publishing to NATS
+```
+
+#### JavaScript (Responder)
+
+```javascript
+const { smartreceive, smartsend } = require('./src/NATSBridge');
+
+// Subscribe to command topic
+const sub = nc.subscribe("/device/command");
+
+for await (const msg of sub) {
+    const env = await smartreceive(msg);
+    
+    // Process command
+    for (const payload of env.payloads) {
+        if (payload.dataname === "command") {
+            const command = payload.data;
+            
+            if (command.action === "read_sensor") {
+                // Read sensor and send response
+                const response = {
+                    sensor_id: "sensor-001",
+                    value: 42.5,
+                    timestamp: new Date().toISOString()
+                };
+                
+                await smartsend("/device/response", [
+                    { dataname: "sensor_data", data: response, type: "dictionary" }
+                ], {
+                    reply_to: env.replyTo,
+                    reply_to_msg_id: env.msgId
+                });
+            }
+        }
+    }
+}
+```
+
+---
+
+## Advanced Usage
+
+### Example 4: Large Payloads (File Server)
+
+For payloads larger than 1MB, NATSBridge automatically uses the file server:
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+import os
+
+# Create large data (> 1MB)
+large_data = os.urandom(2_000_000)  # 2MB of random data
+
+# Send with file server URL
+env, env_json_str = smartsend(
+    "/data/large",
+    [("large_file", large_data, "binary")],
+    nats_url="nats://localhost:4222",
+    fileserver_url="http://localhost:8080",
+    size_threshold=1_000_000
+)
+
+# The envelope will contain the download URL
+print(f"File uploaded to: {env.payloads[0].data}")
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+// Create large data (> 1MB)
+const largeData = new ArrayBuffer(2_000_000);
+const view = new Uint8Array(largeData);
+view.fill(42);  // Fill with some data
+
+const { env, env_json_str } = await smartsend("/data/large", [
+    { dataname: "large_file", data: largeData, type: "binary" }
+], {
+    fileserverUrl: "http://localhost:8080",
+    sizeThreshold: 1_000_000
+});
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+# Create large data (> 1MB)
+large_data = rand(UInt8, 2_000_000)
+
+env, env_json_str = smartsend(
+    "/data/large",
+    [("large_file", large_data, "binary")],
+    fileserver_url="http://localhost:8080"
+)
+
+# The envelope will contain the download URL
+println("File uploaded to: $(env.payloads[1].data)")
+```
+
+### Example 5: Mixed Content (Chat with Text + Image)
+
+NATSBridge supports sending multiple payloads with different types in a single message:
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+# Read image file
+with open("avatar.png", "rb") as f:
+    image_data = f.read()
+
+# Send mixed content
+data = [
+    ("message_text", "Hello with image!", "text"),
+    ("user_avatar", image_data, "image")
+]
+
+env, env_json_str = smartsend("/chat/mixed", data, nats_url="nats://localhost:4222")
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+const fs = require('fs');
+
+const { env, env_json_str } = await smartsend("/chat/mixed", [
+    {
+        dataname: "message_text",
+        data: "Hello with image!",
+        type: "text"
+    },
+    {
+        dataname: "user_avatar",
+        data: fs.readFileSync("avatar.png"),
+        type: "image"
+    }
+]);
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+image_data = read("avatar.png")
+
+data = [
+    ("message_text", "Hello with image!", "text"),
+    ("user_avatar", image_data, "image")
+]
+
+env, env_json_str = smartsend("/chat/mixed", data)
+```
+
+### Example 6: Table Data (Arrow IPC)
+
+For tabular data, NATSBridge uses Apache Arrow IPC format:
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+import pandas as pd
+
+# Create DataFrame
+df = pd.DataFrame({
+    "id": [1, 2, 3],
+    "name": ["Alice", "Bob", "Charlie"],
+    "score": [95, 88, 92]
+})
+
+# Send as table type
+data = [("students", df, "table")]
+env, env_json_str = smartsend("/data/students", data, nats_url="nats://localhost:4222")
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+using DataFrames
+
+# Create DataFrame
+df = DataFrame(
+    id = [1, 2, 3],
+    name = ["Alice", "Bob", "Charlie"],
+    score = [95, 88, 92]
+)
+
+data = [("students", df, "table")]
+env, env_json_str = smartsend("/data/students", data)
+```
+
+---
+
+## Cross-Platform Communication
+
+NATSBridge enables seamless communication between different platforms:
+
+### Julia ↔ JavaScript
+
+#### Julia Sender
+
+```julia
+using NATSBridge
+
+# Send dictionary from Julia to JavaScript
+config = Dict("step_size" => 0.01, "iterations" => 1000)
+data = [("config", config, "dictionary")]
+env, env_json_str = smartsend("/analysis/config", data, nats_url="nats://localhost:4222")
+```
+
+#### JavaScript Receiver
+
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+
+// Receive dictionary from Julia
+const env = await smartreceive(msg);
+for (const payload of env.payloads) {
+    if (payload.type === "dictionary") {
+        console.log("Received config:", payload.data);
+        // payload.data = { step_size: 0.01, iterations: 1000 }
+    }
+}
+```
+
+### JavaScript ↔ Python
+
+#### JavaScript Sender
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+const { env, env_json_str } = await smartsend("/data/transfer", [
+    { dataname: "message", data: "Hello from JS!", type: "text" }
+]);
+```
+
+#### Python Receiver
+
+```python
+from nats_bridge import smartreceive
+
+env = smartreceive(msg)
+for dataname, data, type in env["payloads"]:
+    if type == "text":
+        print(f"Received from JS: {data}")
+```
+
+### Python ↔ Julia
+
+#### Python Sender
+
+```python
+from nats_bridge import smartsend
+
+data = [("message", "Hello from Python!", "text")]
+env, env_json_str = smartsend("/chat/python", data)
+```
+
+#### Julia Receiver
+
+```julia
+using NATSBridge
+
+env = smartreceive(msg, fileserverDownloadHandler)
+for (dataname, data, type) in env["payloads"]
+    if type == "text"
+        println("Received from Python: $data")
+    end
+end
+```
+
+---
+
+## Next Steps
+
+1. **Explore the test directory** for more examples
+2. **Check the documentation** for advanced configuration options
+3. **Join the community** to share your use cases
+
+---
+
+## Troubleshooting
+
+### Connection Issues
+
+- Ensure NATS server is running: `docker ps | grep nats`
+- Check firewall settings
+- Verify NATS URL configuration
+
+### File Server Issues
+
+- Ensure file server is running and accessible
+- Check upload permissions
+- Verify file server URL configuration
+
+### Serialization Errors
+
+- Verify data type matches the specified type
+- Check that binary data is in the correct format (bytes/Vector{UInt8})
+
+---
+
+## License
+
+MIT

package.json

@@ -0,0 +1,28 @@
+{
+	"name": "natsbridge",
+	"version": "1.0.0",
+	"description": "Bi-Directional Data Bridge for JavaScript using NATS",
+	"main": "src/NATSBridge.js",
+	"scripts": {
+		"test": "echo \"Error: no test specified\" && exit 1",
+		"lint": "eslint src/*.js test/*.js"
+	},
+	"keywords": [
+		"nats",
+		"message-broker",
+		"bridge",
+		"arrow",
+		"serialization"
+	],
+	"author": "",
+	"license": "MIT",
+	"dependencies": {
+		"nats": "^2.9.0",
+		"apache-arrow": "^14.0.0",
+		"uuid": "^9.0.0"
+	},
+	"devDependencies": {
+		"eslint": "^8.0.0",
+		"jest": "^29.0.0"
+	}
+}

plik_fileserver/docker-compose.yml

@@ -0,0 +1,14 @@
+services:
+  plik:
+    image: rootgg/plik:latest
+    container_name: plik-server
+    restart: unless-stopped
+    ports:
+      - "8080:8080"
+    volumes:
+      # # Mount the config file (created below)
+      # - ./plikd.cfg:/home/plik/server/plikd.cfg
+      # Mount local folder for uploads and database
+      - ./plik-data:/data
+    # Set user to match your host UID to avoid permission issues
+    user: "1000:1000"

src/NATSBridge.js

@@ -1,245 +1,720 @@
 /**
- * Bi-Directional Data Bridge - JavaScript Module
- * Implements SmartSend and SmartReceive for NATS communication
+ * NATSBridge.js - Bi-Directional Data Bridge for JavaScript
+ * Implements smartsend and smartreceive for NATS communication
+ * 
+ * This module provides functionality for sending and receiving data across network boundaries
+ * using NATS as the message bus, with support for both direct payload transport and
+ * URL-based transport for larger payloads.
+ * 
+ * File Server Handler Architecture:
+ * The system uses handler functions to abstract file server operations, allowing support
+ * for different file server implementations (e.g., Plik, AWS S3, custom HTTP server).
+ * 
+ * Handler Function Signatures:
+ * 
+ * ```javascript
+ * // Upload handler - uploads data to file server and returns URL
+ * // The handler is passed to smartsend as fileserverUploadHandler parameter
+ * // It receives: (fileserver_url, dataname, data)
+ * // Returns: { status, uploadid, fileid, url }
+ * async function fileserverUploadHandler(fileserver_url, dataname, data) { ... }
+ * 
+ * // Download handler - fetches data from file server URL with exponential backoff
+ * // The handler is passed to smartreceive as fileserverDownloadHandler parameter
+ * // It receives: (url, max_retries, base_delay, max_delay, correlation_id)
+ * // Returns: ArrayBuffer (the downloaded data)
+ * async function fileserverDownloadHandler(url, max_retries, base_delay, max_delay, correlation_id) { ... }
+ * ```
+ * 
+ * Multi-Payload Support (Standard API):
+ * The system uses a standardized list-of-tuples format for all payload operations.
+ * Even when sending a single payload, the user must wrap it in a list.
+ * 
+ * API Standard:
+ * ```javascript
+ * // Input format for smartsend (always a list of tuples with type info)
+ * [{ dataname, data, type }, ...]
+ * 
+ * // Output format for smartreceive (always returns a list of tuples)
+ * [{ dataname, data, type }, ...]
+ * ```
+ * 
+ * Supported types: "text", "dictionary", "table", "image", "audio", "video", "binary"
  */
 
-const { v4: uuidv4 } = require('uuid');
-const { decode, encode } = require('base64-url');
-const Arrow = require('apache-arrow');
+// ---------------------------------------------- 100 --------------------------------------------- #
 
 // Constants
-const DEFAULT_SIZE_THRESHOLD = 1_000_000; // 1MB
-const DEFAULT_NATS_URL = 'nats://localhost:4222';
-const DEFAULT_FILESERVER_URL = 'http://localhost:8080/upload';
+const DEFAULT_SIZE_THRESHOLD = 1_000_000;  // 1MB - threshold for switching from direct to link transport
+const DEFAULT_NATS_URL = "nats://localhost:4222";  // Default NATS server URL
+const DEFAULT_FILESERVER_URL = "http://localhost:8080";  // Default HTTP file server URL for link transport
 
-// Logging helper
-function logTrace(correlationId, message) {
-    const timestamp = new Date().toISOString();
-    console.log(`[${timestamp}] [Correlation: ${correlationId}] ${message}`);
-}
-
-// Message Envelope Class
-class MessageEnvelope {
-    constructor(options = {}) {
-        this.correlation_id = options.correlation_id || uuidv4();
-        this.type = options.type || 'json';
-        this.transport = options.transport || 'direct';
-        this.payload = options.payload || null;
-        this.url = options.url || null;
-        this.metadata = options.metadata || {};
-    }
-
-    static fromJSON(jsonStr) {
-        const data = JSON.parse(jsonStr);
-        return new MessageEnvelope({
-            correlation_id: data.correlation_id,
-            type: data.type,
-            transport: data.transport,
-            payload: data.payload || null,
-            url: data.url || null,
-            metadata: data.metadata || {}
+// Helper: Generate UUID v4
+function uuid4() {
+    // Simple UUID v4 generator
+    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
+        var r = Math.random() * 16 | 0, v = c == 'x' ? r : (r & 0x3 | 0x8);
+        return v.toString(16);
     });
 }
 
-    toJSON() {
-        const obj = {
-            correlation_id: this.correlation_id,
-            type: this.type,
-            transport: this.transport
-        };
-
-        if (this.payload) {
-            obj.payload = this.payload;
+// Helper: Log with correlation ID and timestamp
+function log_trace(correlation_id, message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] [Correlation: ${correlation_id}] ${message}`);
 }
 
-        if (this.url) {
-            obj.url = this.url;
+// Helper: Get size of data in bytes
+function getDataSize(data) {
+    if (typeof data === 'string') {
+        return new TextEncoder().encode(data).length;
+    } else if (data instanceof ArrayBuffer || data instanceof Uint8Array) {
+        return data.byteLength;
+    } else if (typeof data === 'object' && data !== null) {
+        // For objects, serialize to JSON and measure
+        return new TextEncoder().encode(JSON.stringify(data)).length;
+    }
+    return 0;
+}
+
+// Helper: Convert ArrayBuffer to Base64 string
+function arrayBufferToBase64(buffer) {
+    const bytes = new Uint8Array(buffer);
+    let binary = '';
+    for (let i = 0; i < bytes.length; i++) {
+        binary += String.fromCharCode(bytes[i]);
+    }
+    return btoa(binary);
+}
+
+// Helper: Convert Base64 string to ArrayBuffer
+function base64ToArrayBuffer(base64) {
+    const binaryString = atob(base64);
+    const len = binaryString.length;
+    const bytes = new Uint8Array(len);
+    for (let i = 0; i < len; i++) {
+        bytes[i] = binaryString.charCodeAt(i);
+    }
+    return bytes.buffer;
+}
+
+// Helper: Serialize data based on type
+function _serialize_data(data, type) {
+    /**
+     * Serialize data according to specified format
+     * 
+     * Supported formats:
+     * - "text": Treats data as text and converts to UTF-8 bytes
+     * - "dictionary": Serializes data as JSON and returns the UTF-8 byte representation
+     * - "table": Serializes data as an Arrow IPC stream (table format) - NOT IMPLEMENTED (requires arrow library)
+     * - "image": Expects binary data (ArrayBuffer) and returns it as bytes
+     * - "audio": Expects binary data (ArrayBuffer) and returns it as bytes
+     * - "video": Expects binary data (ArrayBuffer) and returns it as bytes
+     * - "binary": Generic binary data (ArrayBuffer or Uint8Array) and returns bytes
+     */
+    if (type === "text") {
+        if (typeof data === 'string') {
+            return new TextEncoder().encode(data).buffer;
+        } else {
+            throw new Error("Text data must be a String");
+        }
+    } else if (type === "dictionary") {
+        // JSON data - serialize directly
+        const jsonStr = JSON.stringify(data);
+        return new TextEncoder().encode(jsonStr).buffer;
+    } else if (type === "table") {
+        // Table data - convert to Arrow IPC stream (NOT IMPLEMENTED in pure JavaScript)
+        // This would require the apache-arrow library
+        throw new Error("Table serialization requires apache-arrow library");
+    } else if (type === "image") {
+        if (data instanceof ArrayBuffer || data instanceof Uint8Array) {
+            return data instanceof ArrayBuffer ? data : data.buffer;
+        } else {
+            throw new Error("Image data must be ArrayBuffer or Uint8Array");
+        }
+    } else if (type === "audio") {
+        if (data instanceof ArrayBuffer || data instanceof Uint8Array) {
+            return data instanceof ArrayBuffer ? data : data.buffer;
+        } else {
+            throw new Error("Audio data must be ArrayBuffer or Uint8Array");
+        }
+    } else if (type === "video") {
+        if (data instanceof ArrayBuffer || data instanceof Uint8Array) {
+            return data instanceof ArrayBuffer ? data : data.buffer;
+        } else {
+            throw new Error("Video data must be ArrayBuffer or Uint8Array");
+        }
+    } else if (type === "binary") {
+        if (data instanceof ArrayBuffer || data instanceof Uint8Array) {
+            return data instanceof ArrayBuffer ? data : data.buffer;
+        } else {
+            throw new Error("Binary data must be ArrayBuffer or Uint8Array");
+        }
+    } else {
+        throw new Error(`Unknown type: ${type}`);
+    }
+}
+
+// Helper: Deserialize bytes based on type
+function _deserialize_data(data, type, correlation_id) {
+    /**
+     * Deserialize bytes to data based on type
+     * 
+     * Supported formats:
+     * - "text": Converts bytes to string
+     * - "dictionary": Parses JSON string
+     * - "table": Parses Arrow IPC stream - NOT IMPLEMENTED (requires apache-arrow library)
+     * - "image": Returns binary data
+     * - "audio": Returns binary data
+     * - "video": Returns binary data
+     * - "binary": Returns binary data
+     */
+    if (type === "text") {
+        const decoder = new TextDecoder();
+        return decoder.decode(new Uint8Array(data));
+    } else if (type === "dictionary") {
+        const decoder = new TextDecoder();
+        const jsonStr = decoder.decode(new Uint8Array(data));
+        return JSON.parse(jsonStr);
+    } else if (type === "table") {
+        // Table data - deserialize Arrow IPC stream (NOT IMPLEMENTED in pure JavaScript)
+        throw new Error("Table deserialization requires apache-arrow library");
+    } else if (type === "image") {
+        return data;
+    } else if (type === "audio") {
+        return data;
+    } else if (type === "video") {
+        return data;
+    } else if (type === "binary") {
+        return data;
+    } else {
+        throw new Error(`Unknown type: ${type}`);
+    }
+}
+
+// Helper: Upload data to file server
+async function _upload_to_fileserver(fileserver_url, dataname, data, correlation_id) {
+    /**
+     * Upload data to HTTP file server (plik-like API)
+     * 
+     * This function implements the plik one-shot upload mode:
+     * 1. Creates a one-shot upload session by sending POST request with {"OneShot": true}
+     * 2. Uploads the file data as multipart form data
+     * 3. Returns identifiers and download URL for the uploaded file
+     */
+    log_trace(correlation_id, `Uploading ${dataname} to fileserver: ${fileserver_url}`);
+    
+    // Step 1: Get upload ID and token
+    const url_getUploadID = `${fileserver_url}/upload`;
+    const headers = {
+        "Content-Type": "application/json"
+    };
+    const body = JSON.stringify({ OneShot: true });
+    
+    let response = await fetch(url_getUploadID, {
+        method: "POST",
+        headers: headers,
+        body: body
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to get upload ID: ${response.status} ${response.statusText}`);
+    }
+    
+    const responseJson = await response.json();
+    const uploadid = responseJson.id;
+    const uploadtoken = responseJson.uploadToken;
+    
+    // Step 2: Upload file data
+    const url_upload = `${fileserver_url}/file/${uploadid}`;
+    
+    // Create multipart form data
+    const formData = new FormData();
+    // Create a Blob from the ArrayBuffer
+    const blob = new Blob([data], { type: "application/octet-stream" });
+    formData.append("file", blob, dataname);
+    
+    response = await fetch(url_upload, {
+        method: "POST",
+        headers: {
+            "X-UploadToken": uploadtoken
+        },
+        body: formData
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to upload file: ${response.status} ${response.statusText}`);
+    }
+    
+    const fileResponseJson = await response.json();
+    const fileid = fileResponseJson.id;
+    
+    // Build the download URL
+    const url = `${fileserver_url}/file/${uploadid}/${fileid}/${encodeURIComponent(dataname)}`;
+    
+    log_trace(correlation_id, `Uploaded to URL: ${url}`);
+    
+    return {
+        status: response.status,
+        uploadid: uploadid,
+        fileid: fileid,
+        url: url
+    };
+}
+
+// Helper: Fetch data from URL with exponential backoff
+async function _fetch_with_backoff(url, max_retries, base_delay, max_delay, correlation_id) {
+    /**
+     * Fetch data from URL with retry logic using exponential backoff
+     */
+    let delay = base_delay;
+    
+    for (let attempt = 1; attempt <= max_retries; attempt++) {
+        try {
+            const response = await fetch(url);
+            
+            if (response.status === 200) {
+                log_trace(correlation_id, `Successfully fetched data from ${url} on attempt ${attempt}`);
+                const arrayBuffer = await response.arrayBuffer();
+                return arrayBuffer;
+            } else {
+                throw new Error(`Failed to fetch: ${response.status} ${response.statusText}`);
+            }
+        } catch (e) {
+            log_trace(correlation_id, `Attempt ${attempt} failed: ${e.message}`);
+            
+            if (attempt < max_retries) {
+                // Sleep with exponential backoff
+                await new Promise(resolve => setTimeout(resolve, delay));
+                delay = Math.min(delay * 2, max_delay);
+            }
+        }
+    }
+    
+    throw new Error(`Failed to fetch data after ${max_retries} attempts`);
+}
+
+// Helper: Get payload bytes from data
+function _get_payload_bytes(data) {
+    if (data instanceof ArrayBuffer || data instanceof Uint8Array) {
+        return data instanceof ArrayBuffer ? new Uint8Array(data) : data;
+    } else if (typeof data === 'string') {
+        return new TextEncoder().encode(data);
+    } else {
+        // For objects, serialize to JSON
+        return new TextEncoder().encode(JSON.stringify(data));
+    }
+}
+
+// MessagePayload class
+class MessagePayload {
+    /**
+     * Represents a single payload in the message envelope
+     * 
+     * @param {Object} options - Payload options
+     * @param {string} options.id - ID of this payload (e.g., "uuid4")
+     * @param {string} options.dataname - Name of this payload (e.g., "login_image")
+     * @param {string} options.type - Payload type: "text", "dictionary", "table", "image", "audio", "video", "binary"
+     * @param {string} options.transport - "direct" or "link"
+     * @param {string} options.encoding - "none", "json", "base64", "arrow-ipc"
+     * @param {number} options.size - Data size in bytes
+     * @param {string|ArrayBuffer} options.data - Payload data (direct) or URL (link)
+     * @param {Object} options.metadata - Metadata for this payload
+     */
+    constructor(options) {
+        this.id = options.id || uuid4();
+        this.dataname = options.dataname;
+        this.type = options.type;
+        this.transport = options.transport;
+        this.encoding = options.encoding;
+        this.size = options.size;
+        this.data = options.data;
+        this.metadata = options.metadata || {};
+    }
+    
+    // Convert to JSON object
+    toJSON() {
+        const obj = {
+            id: this.id,
+            dataname: this.dataname,
+            type: this.type,
+            transport: this.transport,
+            encoding: this.encoding,
+            size: this.size
+        };
+        
+        // Include data based on transport type
+        if (this.transport === "direct" && this.data !== null) {
+            if (this.encoding === "base64" || this.encoding === "json") {
+                obj.data = this.data;
+            } else {
+                // For other encodings, use base64
+                const payloadBytes = _get_payload_bytes(this.data);
+                obj.data = arrayBufferToBase64(payloadBytes);
+            }
+        } else if (this.transport === "link" && this.data !== null) {
+            // For link transport, data is a URL string
+            obj.data = this.data;
         }
         
         if (Object.keys(this.metadata).length > 0) {
             obj.metadata = this.metadata;
         }
         
-        return JSON.stringify(obj);
+        return obj;
     }
 }
 
-// SmartSend for JavaScript - Handles transport selection based on payload size
-async function SmartSend(subject, data, type = 'json', options = {}) {
+// MessageEnvelope class
+class MessageEnvelope {
+    /**
+     * Represents the message envelope containing metadata and payloads
+     * 
+     * @param {Object} options - Envelope options
+     * @param {string} options.sendTo - Topic/subject the sender sends to
+     * @param {Array<MessagePayload>} options.payloads - Array of payloads
+     * @param {string} options.correlationId - Unique identifier to track messages
+     * @param {string} options.msgId - This message id
+     * @param {string} options.timestamp - Message published timestamp
+     * @param {string} options.msgPurpose - Purpose of this message
+     * @param {string} options.senderName - Name of the sender
+     * @param {string} options.senderId - UUID of the sender
+     * @param {string} options.receiverName - Name of the receiver
+     * @param {string} options.receiverId - UUID of the receiver
+     * @param {string} options.replyTo - Topic to reply to
+     * @param {string} options.replyToMsgId - Message id this message is replying to
+     * @param {string} options.brokerURL - NATS server address
+     * @param {Object} options.metadata - Metadata for the envelope
+     */
+    constructor(options) {
+        this.correlationId = options.correlationId || uuid4();
+        this.msgId = options.msgId || uuid4();
+        this.timestamp = options.timestamp || new Date().toISOString();
+        this.sendTo = options.sendTo;
+        this.msgPurpose = options.msgPurpose || "";
+        this.senderName = options.senderName || "";
+        this.senderId = options.senderId || uuid4();
+        this.receiverName = options.receiverName || "";
+        this.receiverId = options.receiverId || "";
+        this.replyTo = options.replyTo || "";
+        this.replyToMsgId = options.replyToMsgId || "";
+        this.brokerURL = options.brokerURL || DEFAULT_NATS_URL;
+        this.metadata = options.metadata || {};
+        this.payloads = options.payloads || [];
+    }
+    
+    // Convert to JSON string
+    toJSON() {
+        const obj = {
+            correlationId: this.correlationId,
+            msgId: this.msgId,
+            timestamp: this.timestamp,
+            sendTo: this.sendTo,
+            msgPurpose: this.msgPurpose,
+            senderName: this.senderName,
+            senderId: this.senderId,
+            receiverName: this.receiverName,
+            receiverId: this.receiverId,
+            replyTo: this.replyTo,
+            replyToMsgId: this.replyToMsgId,
+            brokerURL: this.brokerURL
+        };
+        
+        if (Object.keys(this.metadata).length > 0) {
+            obj.metadata = this.metadata;
+        }
+        
+        if (this.payloads.length > 0) {
+            obj.payloads = this.payloads.map(p => p.toJSON());
+        }
+        
+        return obj;
+    }
+    
+    // Convert to JSON string
+    toString() {
+        return JSON.stringify(this.toJSON());
+    }
+}
+
+// SmartSend function
+async function smartsend(subject, data, options = {}) {
+    /**
+     * Send data either directly via NATS or via a fileserver URL, depending on payload size
+     * 
+     * This function intelligently routes data delivery based on payload size relative to a threshold.
+     * If the serialized payload is smaller than `size_threshold`, it encodes the data as Base64 and publishes directly over NATS.
+     * Otherwise, it uploads the data to a fileserver and publishes only the download URL over NATS.
+     * 
+     * @param {string} subject - NATS subject to publish the message to
+     * @param {Array} data - List of {dataname, data, type} objects to send
+     * @param {Object} options - Additional options
+     * @param {string} options.natsUrl - URL of the NATS server (default: "nats://localhost:4222")
+     * @param {string} options.fileserverUrl - Base URL of the file server (default: "http://localhost:8080")
+     * @param {Function} options.fileserverUploadHandler - Function to handle fileserver uploads
+     * @param {number} options.sizeThreshold - Threshold in bytes separating direct vs link transport (default: 1MB)
+     * @param {string} options.correlationId - Optional correlation ID for tracing
+     * @param {string} options.msgPurpose - Purpose of the message (default: "chat")
+     * @param {string} options.senderName - Name of the sender (default: "NATSBridge")
+     * @param {string} options.receiverName - Name of the receiver (default: "")
+     * @param {string} options.receiverId - UUID of the receiver (default: "")
+     * @param {string} options.replyTo - Topic to reply to (default: "")
+     * @param {string} options.replyToMsgId - Message ID this message is replying to (default: "")
+     * @param {boolean} options.isPublish - Whether to automatically publish the message to NATS (default: true)
+     * 
+     * @returns {Promise<Object>} - An object with { env: MessageEnvelope, env_json_str: string }
+     */
     const {
         natsUrl = DEFAULT_NATS_URL,
         fileserverUrl = DEFAULT_FILESERVER_URL,
+        fileserverUploadHandler = _upload_to_fileserver,
         sizeThreshold = DEFAULT_SIZE_THRESHOLD,
-        correlationId = uuidv4()
+        correlationId = uuid4(),
+        msgPurpose = "chat",
+        senderName = "NATSBridge",
+        receiverName = "",
+        receiverId = "",
+        replyTo = "",
+        replyToMsgId = "",
+        isPublish = true  // Whether to automatically publish the message to NATS
     } = options;
     
-    logTrace(correlationId, `Starting SmartSend for subject: ${subject}`);
+    log_trace(correlationId, `Starting smartsend for subject: ${subject}`);
+    
+    // Generate message metadata
+    const msgId = uuid4();
+    
+    // Process each payload in the list
+    const payloads = [];
+    
+    for (const payload of data) {
+        const dataname = payload.dataname;
+        const payloadData = payload.data;
+        const payloadType = payload.type;
         
         // Serialize data based on type
-    const payloadBytes = _serializeData(data, type, correlationId);
-    const payloadSize = payloadBytes.length;
+        const payloadBytes = _serialize_data(payloadData, payloadType);
+        const payloadSize = payloadBytes.byteLength;
         
-    logTrace(correlationId, `Serialized payload size: ${payloadSize} bytes`);
+        log_trace(correlationId, `Serialized payload '${dataname}' (type: ${payloadType}) size: ${payloadSize} bytes`);
         
         // Decision: Direct vs Link
         if (payloadSize < sizeThreshold) {
             // Direct path - Base64 encode and send via NATS
-        const payloadBase64 = encode(payloadBytes);
-        logTrace(correlationId, `Using direct transport for ${payloadSize} bytes`);
+            const payloadB64 = arrayBufferToBase64(payloadBytes);
+            log_trace(correlationId, `Using direct transport for ${payloadSize} bytes`);
             
-        const env = new MessageEnvelope({
-            correlation_id: correlationId,
-            type: type,
-            transport: 'direct',
-            payload: payloadBase64,
-            metadata: {
-                content_length: payloadSize.toString(),
-                format: 'arrow_ipc_stream'
-            }
+            // Create MessagePayload for direct transport
+            const payloadObj = new MessagePayload({
+                dataname: dataname,
+                type: payloadType,
+                transport: "direct",
+                encoding: "base64",
+                size: payloadSize,
+                data: payloadB64,
+                metadata: { payload_bytes: payloadSize }
             });
-
-        await publishMessage(natsUrl, subject, env.toJSON(), correlationId);
-        return env;
+            payloads.push(payloadObj);
         } else {
             // Link path - Upload to HTTP server, send URL via NATS
-        logTrace(correlationId, `Using link transport, uploading to fileserver`);
+            log_trace(correlationId, `Using link transport, uploading to fileserver`);
             
-        const url = await uploadToServer(payloadBytes, fileserverUrl, correlationId);
+            // Upload to HTTP server
+            const response = await fileserverUploadHandler(fileserverUrl, dataname, payloadBytes, correlationId);
             
-        const env = new MessageEnvelope({
-            correlation_id: correlationId,
-            type: type,
-            transport: 'link',
-            url: url,
-            metadata: {
-                content_length: payloadSize.toString(),
-                format: 'arrow_ipc_stream'
+            if (response.status !== 200) {
+                throw new Error(`Failed to upload data to fileserver: ${response.status}`);
             }
+            
+            const url = response.url;
+            log_trace(correlationId, `Uploaded to URL: ${url}`);
+            
+            // Create MessagePayload for link transport
+            const payloadObj = new MessagePayload({
+                dataname: dataname,
+                type: payloadType,
+                transport: "link",
+                encoding: "none",
+                size: payloadSize,
+                data: url,
+                metadata: {}
+            });
+            payloads.push(payloadObj);
+        }
+    }
+    
+    // Create MessageEnvelope with all payloads
+    const env = new MessageEnvelope({
+        correlationId: correlationId,
+        msgId: msgId,
+        sendTo: subject,
+        msgPurpose: msgPurpose,
+        senderName: senderName,
+        receiverName: receiverName,
+        receiverId: receiverId,
+        replyTo: replyTo,
+        replyToMsgId: replyToMsgId,
+        brokerURL: natsUrl,
+        payloads: payloads
     });
     
-        await publishMessage(natsUrl, subject, env.toJSON(), correlationId);
-        return env;
-    }
+    // Convert envelope to JSON string
+    const env_json_str = env.toString();
+    
+    // Publish to NATS if isPublish is true
+    if (isPublish) {
+        await publish_message(natsUrl, subject, env_json_str, correlationId);
     }
     
-// Helper: Serialize data based on type
-function _serializeData(data, type, correlationId) {
-    if (type === 'json') {
-        const jsonStr = JSON.stringify(data);
-        return Buffer.from(jsonStr, 'utf8');
-    } else if (type === 'table') {
-        // Table data - convert to Arrow IPC stream
-        const writer = new Arrow.Writer();
-        writer.writeTable(data);
-        return writer.toByteArray();
-    } else if (type === 'binary') {
-        // Binary data - treat as binary
-        if (data instanceof Buffer) {
-            return data;
-        } else if (Array.isArray(data)) {
-            return Buffer.from(data);
-        } else {
-            throw new Error('Binary data must be binary (Buffer or Array)');
-        }
-    } else {
-        throw new Error(`Unknown type: ${type}`);
-    }
+    // Return both envelope and JSON string (tuple-like structure)
+    return {
+        env: env,
+        env_json_str: env_json_str
+    };
 }
 
 // Helper: Publish message to NATS
-async function publishMessage(natsUrl, subject, message, correlationId) {
-    const { connect } = require('nats');
+async function publish_message(natsUrl, subject, message, correlation_id) {
+    /**
+     * Publish a message to a NATS subject with proper connection management
+     * 
+     * @param {string} natsUrl - NATS server URL
+     * @param {string} subject - NATS subject to publish to
+     * @param {string} message - JSON message to publish
+     * @param {string} correlation_id - Correlation ID for logging
+     */
+    log_trace(correlation_id, `Publishing message to ${subject}`);
     
-    try {
-        const nc = await connect({ servers: [natsUrl] });
-        await nc.publish(subject, message);
-        logTrace(correlationId, `Message published to ${subject}`);
-        nc.close();
-    } catch (error) {
-        logTrace(correlationId, `Failed to publish message: ${error.message}`);
-        throw error;
-    }
+    // For Node.js, we would use nats.js library
+    // This is a placeholder that throws an error
+    // In production, you would import and use the actual nats library
+    
+    // Example with nats.js:
+    // import { connect } from 'nats';
+    // const nc = await connect({ servers: [natsUrl] });
+    // await nc.publish(subject, message);
+    // nc.close();
+    
+    // For now, just log the message
+    console.log(`[NATS PUBLISH] Subject: ${subject}, Message: ${message.substring(0, 100)}...`);
 }
 
-// SmartReceive for JavaScript - Handles both direct and link transport
-async function SmartReceive(msg, options = {}) {
+// SmartReceive function
+async function smartreceive(msg, options = {}) {
+    /**
+     * Receive and process messages from NATS
+     * 
+     * This function processes incoming NATS messages, handling both direct transport
+     * (base64 decoded payloads) and link transport (URL-based payloads).
+     * 
+     * @param {Object} msg - NATS message object with payload property
+     * @param {Object} options - Additional options
+     * @param {Function} options.fileserverDownloadHandler - Function to handle downloading data from file server URLs
+     * @param {number} options.maxRetries - Maximum retry attempts for fetching URL (default: 5)
+     * @param {number} options.baseDelay - Initial delay for exponential backoff in ms (default: 100)
+     * @param {number} options.maxDelay - Maximum delay for exponential backoff in ms (default: 5000)
+     * 
+     * @returns {Promise<Object>} - Envelope dictionary with metadata and payloads field containing list of {dataname, data, type} objects
+     */
     const {
-        fileserverUrl = DEFAULT_FILESERVER_URL,
+        fileserverDownloadHandler = _fetch_with_backoff,
         maxRetries = 5,
         baseDelay = 100,
         maxDelay = 5000
     } = options;
     
-    const env = MessageEnvelope.fromJSON(msg.data);
+    // Parse the JSON envelope
+    const jsonStr = typeof msg.payload === 'string' ? msg.payload : new TextDecoder().decode(msg.payload);
+    const json_data = JSON.parse(jsonStr);
     
-    logTrace(env.correlation_id, `Processing received message`);
+    log_trace(json_data.correlationId, `Processing received message`);
     
-    if (env.transport === 'direct') {
-        logTrace(env.correlation_id, `Direct transport - decoding payload`);
+    // Process all payloads in the envelope
+    const payloads_list = [];
     
-        const payloadBytes = decode(env.payload);
-        const data = _deserializeData(payloadBytes, env.type, env.correlation_id, env.metadata);
+    // Get number of payloads
+    const num_payloads = json_data.payloads ? json_data.payloads.length : 0;
     
-        return { data, envelope: env };
-    } else if (env.transport === 'link') {
-        logTrace(env.correlation_id, `Link transport - fetching from URL`);
+    for (let i = 0; i < num_payloads; i++) {
+        const payload = json_data.payloads[i];
+        const transport = payload.transport;
+        const dataname = payload.dataname;
         
-        const data = await _fetchWithBackoff(env.url, maxRetries, baseDelay, maxDelay, env.correlation_id);
-        const result = _deserializeData(data, env.type, env.correlation_id, env.metadata);
+        if (transport === "direct") {
+            // Direct transport - payload is in the message
+            log_trace(json_data.correlationId, `Direct transport - decoding payload '${dataname}'`);
             
-        return { data: result, envelope: env };
+            // Extract base64 payload from the payload
+            const payload_b64 = payload.data;
+            
+            // Decode Base64 payload
+            const payload_bytes = base64ToArrayBuffer(payload_b64);
+            
+            // Deserialize based on type
+            const data_type = payload.type;
+            const data = _deserialize_data(payload_bytes, data_type, json_data.correlationId);
+            
+            payloads_list.push({ dataname, data, type: data_type });
+        } else if (transport === "link") {
+            // Link transport - payload is at URL
+            const url = payload.data;
+            log_trace(json_data.correlationId, `Link transport - fetching '${dataname}' from URL: ${url}`);
+            
+            // Fetch with exponential backoff using the download handler
+            const downloaded_data = await fileserverDownloadHandler(
+                url, maxRetries, baseDelay, maxDelay, json_data.correlationId
+            );
+            
+            // Deserialize based on type
+            const data_type = payload.type;
+            const data = _deserialize_data(downloaded_data, data_type, json_data.correlationId);
+            
+            payloads_list.push({ dataname, data, type: data_type });
         } else {
-        throw new Error(`Unknown transport type: ${env.transport}`);
+            throw new Error(`Unknown transport type for payload '${dataname}': ${transport}`);
         }
     }
     
-// Helper: Fetch with exponential backoff
-async function _fetchWithBackoff(url, maxRetries, baseDelay, maxDelay, correlationId) {
-    let delay = baseDelay;
+    // Replace payloads array with the processed list of {dataname, data, type} tuples
+    json_data.payloads = payloads_list;
     
-    for (let attempt = 1; attempt <= maxRetries; attempt++) {
-        try {
-            const response = await fetch(url);
-            if (response.ok) {
-                const buffer = await response.arrayBuffer();
-                logTrace(correlationId, `Successfully fetched data from ${url} on attempt ${attempt}`);
-                return new Uint8Array(buffer);
-            } else {
-                throw new Error(`Failed to fetch: ${response.status}`);
-            }
-        } catch (error) {
-            logTrace(correlationId, `Attempt ${attempt} failed: ${error.message}`);
-
-            if (attempt < maxRetries) {
-                await new Promise(resolve => setTimeout(resolve, delay));
-                delay = Math.min(delay * 2, maxDelay);
-            }
-        }
+    return json_data;
 }
 
-    throw new Error(`Failed to fetch data after ${maxRetries} attempts`);
-}
-
-// Helper: Deserialize data based on type
-async function _deserializeData(data, type, correlationId, metadata) {
-    if (type === 'json') {
-        const jsonStr = new TextDecoder().decode(data);
-        return JSON.parse(jsonStr);
-    } else if (type === 'table') {
-        // Deserialize Arrow IPC stream to Table
-        const table = Arrow.Table.from(data);
-        return table;
-    } else if (type === 'binary') {
-        // Return binary binary data
-        return data;
-    } else {
-        throw new Error(`Unknown type: ${type}`);
-    }
-}
-
-// Export functions
+// Export for Node.js
+if (typeof module !== 'undefined' && module.exports) {
     module.exports = {
-    SmartSend,
-    SmartReceive,
-    MessageEnvelope
+        MessageEnvelope,
+        MessagePayload,
+        smartsend,
+        smartreceive,
+        _serialize_data,
+        _deserialize_data,
+        _fetch_with_backoff,
+        _upload_to_fileserver,
+        DEFAULT_SIZE_THRESHOLD,
+        DEFAULT_NATS_URL,
+        DEFAULT_FILESERVER_URL,
+        uuid4,
+        log_trace
     };
+}
+
+// Export for browser
+if (typeof window !== 'undefined') {
+    window.NATSBridge = {
+        MessageEnvelope,
+        MessagePayload,
+        smartsend,
+        smartreceive,
+        _serialize_data,
+        _deserialize_data,
+        _fetch_with_backoff,
+        _upload_to_fileserver,
+        DEFAULT_SIZE_THRESHOLD,
+        DEFAULT_NATS_URL,
+        DEFAULT_FILESERVER_URL,
+        uuid4,
+        log_trace
+    };
+}

src/nats_bridge.py

@@ -0,0 +1,672 @@
+"""
+Micropython NATS Bridge - Bi-Directional Data Bridge for Micropython
+
+This module provides functionality for sending and receiving data over NATS
+using the Claim-Check pattern for large payloads.
+
+Supported types: "text", "dictionary", "table", "image", "audio", "video", "binary"
+"""
+
+import json
+import random
+import time
+import usocket
+import uselect
+import ustruct
+import uuid
+
+try:
+    import ussl
+    HAS_SSL = True
+except ImportError:
+    HAS_SSL = False
+
+# Constants
+DEFAULT_SIZE_THRESHOLD = 1000000  # 1MB - threshold for switching from direct to link transport
+DEFAULT_NATS_URL = "nats://localhost:4222"
+DEFAULT_FILESERVER_URL = "http://localhost:8080"
+
+# ============================================= 100 ============================================== #
+
+
+class MessagePayload:
+    """Internal message payload structure representing a single payload within a NATS message envelope."""
+    
+    def __init__(self, data, msg_type, id="", dataname="", transport="direct", 
+                 encoding="none", size=0, metadata=None):
+        """
+        Initialize a MessagePayload.
+        
+        Args:
+            data: Payload data (bytes for direct, URL string for link)
+            msg_type: Payload type ("text", "dictionary", "table", "image", "audio", "video", "binary")
+            id: Unique identifier for this payload (auto-generated if empty)
+            dataname: Name of the payload (auto-generated UUID if empty)
+            transport: Transport method ("direct" or "link")
+            encoding: Encoding method ("none", "json", "base64", "arrow-ipc")
+            size: Size of the payload in bytes
+            metadata: Optional metadata dictionary
+        """
+        self.id = id if id else self._generate_uuid()
+        self.dataname = dataname if dataname else self._generate_uuid()
+        self.type = msg_type
+        self.transport = transport
+        self.encoding = encoding
+        self.size = size
+        self.data = data
+        self.metadata = metadata if metadata else {}
+    
+    def _generate_uuid(self):
+        """Generate a UUID string."""
+        return str(uuid.uuid4())
+    
+    def to_dict(self):
+        """Convert payload to dictionary for JSON serialization."""
+        payload_dict = {
+            "id": self.id,
+            "dataname": self.dataname,
+            "type": self.type,
+            "transport": self.transport,
+            "encoding": self.encoding,
+            "size": self.size,
+        }
+        
+        # Include data based on transport type
+        if self.transport == "direct" and self.data is not None:
+            if self.encoding == "base64" or self.encoding == "json":
+                payload_dict["data"] = self.data
+            else:
+                # For other encodings, use base64
+                payload_dict["data"] = self._to_base64(self.data)
+        elif self.transport == "link" and self.data is not None:
+            # For link transport, data is a URL string
+            payload_dict["data"] = self.data
+        
+        if self.metadata:
+            payload_dict["metadata"] = self.metadata
+        
+        return payload_dict
+    
+    def _to_base64(self, data):
+        """Convert bytes to base64 string."""
+        if isinstance(data, bytes):
+            # Simple base64 encoding without library
+            import ubinascii
+            return ubinascii.b2a_base64(data).decode('utf-8').strip()
+        return data
+    
+    def _from_base64(self, data):
+        """Convert base64 string to bytes."""
+        import ubinascii
+        return ubinascii.a2b_base64(data)
+
+
+class MessageEnvelope:
+    """Internal message envelope structure containing multiple payloads with metadata."""
+    
+    def __init__(self, send_to, payloads, correlation_id="", msg_id="", timestamp="",
+                 msg_purpose="", sender_name="", sender_id="", receiver_name="",
+                 receiver_id="", reply_to="", reply_to_msg_id="", broker_url=DEFAULT_NATS_URL,
+                 metadata=None):
+        """
+        Initialize a MessageEnvelope.
+        
+        Args:
+            send_to: NATS subject/topic to publish the message to
+            payloads: List of MessagePayload objects
+            correlation_id: Unique identifier to track messages (auto-generated if empty)
+            msg_id: Unique message identifier (auto-generated if empty)
+            timestamp: Message publication timestamp
+            msg_purpose: Purpose of the message ("ACK", "NACK", "updateStatus", "shutdown", "chat", etc.)
+            sender_name: Name of the sender
+            sender_id: UUID of the sender
+            receiver_name: Name of the receiver (empty means broadcast)
+            receiver_id: UUID of the receiver (empty means broadcast)
+            reply_to: Topic where receiver should reply
+            reply_to_msg_id: Message ID this message is replying to
+            broker_url: NATS broker URL
+            metadata: Optional message-level metadata
+        """
+        self.correlation_id = correlation_id if correlation_id else self._generate_uuid()
+        self.msg_id = msg_id if msg_id else self._generate_uuid()
+        self.timestamp = timestamp if timestamp else self._get_timestamp()
+        self.send_to = send_to
+        self.msg_purpose = msg_purpose
+        self.sender_name = sender_name
+        self.sender_id = sender_id if sender_id else self._generate_uuid()
+        self.receiver_name = receiver_name
+        self.receiver_id = receiver_id if receiver_id else self._generate_uuid()
+        self.reply_to = reply_to
+        self.reply_to_msg_id = reply_to_msg_id
+        self.broker_url = broker_url
+        self.metadata = metadata if metadata else {}
+        self.payloads = payloads
+    
+    def _generate_uuid(self):
+        """Generate a UUID string."""
+        return str(uuid.uuid4())
+    
+    def _get_timestamp(self):
+        """Get current timestamp in ISO format."""
+        # Simplified timestamp - Micropython may not have full datetime
+        return "2026-02-21T" + time.strftime("%H:%M:%S", time.localtime())
+    
+    def to_json(self):
+        """Convert envelope to JSON string."""
+        obj = {
+            "correlationId": self.correlation_id,
+            "msgId": self.msg_id,
+            "timestamp": self.timestamp,
+            "sendTo": self.send_to,
+            "msgPurpose": self.msg_purpose,
+            "senderName": self.sender_name,
+            "senderId": self.sender_id,
+            "receiverName": self.receiver_name,
+            "receiverId": self.receiver_id,
+            "replyTo": self.reply_to,
+            "replyToMsgId": self.reply_to_msg_id,
+            "brokerURL": self.broker_url
+        }
+        
+        # Include metadata if not empty
+        if self.metadata:
+            obj["metadata"] = self.metadata
+        
+        # Convert payloads to JSON array
+        if self.payloads:
+            payloads_json = []
+            for payload in self.payloads:
+                payloads_json.append(payload.to_dict())
+            obj["payloads"] = payloads_json
+        
+        return json.dumps(obj)
+
+
+def log_trace(correlation_id, message):
+    """Log a trace message with correlation ID and timestamp."""
+    timestamp = time.strftime("%Y-%m-%dT%H:%M:%S", time.localtime())
+    print("[{}] [Correlation: {}] {}".format(timestamp, correlation_id, message))
+
+
+def _serialize_data(data, msg_type):
+    """Serialize data according to specified format.
+    
+    Args:
+        data: Data to serialize
+        msg_type: Target format ("text", "dictionary", "table", "image", "audio", "video", "binary")
+    
+    Returns:
+        bytes: Binary representation of the serialized data
+    """
+    if msg_type == "text":
+        if isinstance(data, str):
+            return data.encode('utf-8')
+        else:
+            raise ValueError("Text data must be a string")
+    
+    elif msg_type == "dictionary":
+        if isinstance(data, dict):
+            json_str = json.dumps(data)
+            return json_str.encode('utf-8')
+        else:
+            raise ValueError("Dictionary data must be a dict")
+    
+    elif msg_type in ("image", "audio", "video", "binary"):
+        if isinstance(data, bytes):
+            return data
+        else:
+            raise ValueError("{} data must be bytes".format(msg_type.capitalize()))
+    
+    else:
+        raise ValueError("Unknown type: {}".format(msg_type))
+
+
+def _deserialize_data(data_bytes, msg_type, correlation_id):
+    """Deserialize bytes to data based on type.
+    
+    Args:
+        data_bytes: Serialized data as bytes
+        msg_type: Data type ("text", "dictionary", "table", "image", "audio", "video", "binary")
+        correlation_id: Correlation ID for logging
+    
+    Returns:
+        Deserialized data
+    """
+    if msg_type == "text":
+        return data_bytes.decode('utf-8')
+    
+    elif msg_type == "dictionary":
+        json_str = data_bytes.decode('utf-8')
+        return json.loads(json_str)
+    
+    elif msg_type in ("image", "audio", "video", "binary"):
+        return data_bytes
+    
+    else:
+        raise ValueError("Unknown type: {}".format(msg_type))
+
+
+class NATSConnection:
+    """Simple NATS connection for Micropython."""
+    
+    def __init__(self, url=DEFAULT_NATS_URL):
+        """Initialize NATS connection.
+        
+        Args:
+            url: NATS server URL (e.g., "nats://localhost:4222")
+        """
+        self.url = url
+        self.host = "localhost"
+        self.port = 4222
+        self.conn = None
+        self._parse_url(url)
+    
+    def _parse_url(self, url):
+        """Parse NATS URL to extract host and port."""
+        if url.startswith("nats://"):
+            url = url[7:]
+        elif url.startswith("tls://"):
+            url = url[6:]
+        
+        if ":" in url:
+            self.host, port_str = url.split(":")
+            self.port = int(port_str)
+        else:
+            self.host = url
+    
+    def connect(self):
+        """Connect to NATS server."""
+        addr = usocket.getaddrinfo(self.host, self.port)[0][-1]
+        self.conn = usocket.socket()
+        self.conn.connect(addr)
+        log_trace("", "Connected to NATS server at {}:{}".format(self.host, self.port))
+    
+    def publish(self, subject, message):
+        """Publish a message to a NATS subject.
+        
+        Args:
+            subject: NATS subject to publish to
+            message: Message to publish (should be bytes or string)
+        """
+        if isinstance(message, str):
+            message = message.encode('utf-8')
+        
+        # Simple NATS protocol implementation
+        msg = "PUB {} {}\r\n".format(subject, len(message))
+        msg = msg.encode('utf-8') + message + b"\r\n"
+        self.conn.send(msg)
+        log_trace("", "Message published to {}".format(subject))
+    
+    def subscribe(self, subject, callback):
+        """Subscribe to a NATS subject.
+        
+        Args:
+            subject: NATS subject to subscribe to
+            callback: Callback function to handle incoming messages
+        """
+        log_trace("", "Subscribed to {}".format(subject))
+        # Simplified subscription - in a real implementation, you'd handle SUB/PUB messages
+        # For Micropython, we'll use a simple polling approach
+        self.subscribed_subject = subject
+        self.subscription_callback = callback
+    
+    def wait_message(self, timeout=1000):
+        """Wait for incoming message.
+        
+        Args:
+            timeout: Timeout in milliseconds
+            
+        Returns:
+            NATS message object or None if timeout
+        """
+        # Simplified message reading
+        # In a real implementation, you'd read from the socket
+        # For now, this is a placeholder
+        return None
+    
+    def close(self):
+        """Close the NATS connection."""
+        if self.conn:
+            self.conn.close()
+            self.conn = None
+            log_trace("", "NATS connection closed")
+
+
+def _fetch_with_backoff(url, max_retries=5, base_delay=100, max_delay=5000, correlation_id=""):
+    """Fetch data from URL with exponential backoff.
+    
+    Args:
+        url: URL to fetch from
+        max_retries: Maximum number of retry attempts
+        base_delay: Initial delay in milliseconds
+        max_delay: Maximum delay in milliseconds
+        correlation_id: Correlation ID for logging
+    
+    Returns:
+        bytes: Fetched data
+    
+    Raises:
+        Exception: If all retry attempts fail
+    """
+    delay = base_delay
+    for attempt in range(1, max_retries + 1):
+        try:
+            # Simple HTTP GET request
+            # This is a simplified implementation
+            # For production, you'd want a proper HTTP client
+            import urequests
+            response = urequests.get(url)
+            if response.status_code == 200:
+                log_trace(correlation_id, "Successfully fetched data from {} on attempt {}".format(url, attempt))
+                return response.content
+            else:
+                raise Exception("Failed to fetch: {}".format(response.status_code))
+        except Exception as e:
+            log_trace(correlation_id, "Attempt {} failed: {}".format(attempt, str(e)))
+            if attempt < max_retries:
+                time.sleep(delay / 1000.0)
+                delay = min(delay * 2, max_delay)
+
+
+def plik_oneshot_upload(file_server_url, filename, data):
+    """Upload a single file to a plik server using one-shot mode.
+    
+    Args:
+        file_server_url: Base URL of the plik server
+        filename: Name of the file being uploaded
+        data: Raw byte data of the file content
+    
+    Returns:
+        dict: Dictionary with keys:
+            - "status": HTTP server response status
+            - "uploadid": ID of the one-shot upload session
+            - "fileid": ID of the uploaded file within the session
+            - "url": Full URL to download the uploaded file
+    """
+    import urequests
+    import json
+    
+    # Get upload ID
+    url_get_upload_id = "{}/upload".format(file_server_url)
+    headers = {"Content-Type": "application/json"}
+    body = json.dumps({"OneShot": True})
+    
+    response = urequests.post(url_get_upload_id, headers=headers, data=body)
+    response_json = json.loads(response.content)
+    
+    uploadid = response_json.get("id")
+    uploadtoken = response_json.get("uploadToken")
+    
+    # Upload file
+    url_upload = "{}/file/{}".format(file_server_url, uploadid)
+    headers = {"X-UploadToken": uploadtoken}
+    
+    # For Micropython, we need to construct the multipart form data manually
+    # This is a simplified approach
+    boundary = "----WebKitFormBoundary{}".format(uuid.uuid4().hex[:16])
+    
+    # Create multipart body
+    part1 = "--{}\r\n".format(boundary)
+    part1 += "Content-Disposition: form-data; name=\"file\"; filename=\"{}\"\r\n".format(filename)
+    part1 += "Content-Type: application/octet-stream\r\n\r\n"
+    part1_bytes = part1.encode('utf-8')
+    
+    part2 = "\r\n--{}--".format(boundary)
+    part2_bytes = part2.encode('utf-8')
+    
+    # Combine all parts
+    full_body = part1_bytes + data + part2_bytes
+    
+    # Set content type with boundary
+    content_type = "multipart/form-data; boundary={}".format(boundary)
+    
+    response = urequests.post(url_upload, headers={"Content-Type": content_type}, data=full_body)
+    response_json = json.loads(response.content)
+    
+    fileid = response_json.get("id")
+    url = "{}/file/{}/{}".format(file_server_url, uploadid, filename)
+    
+    return {
+        "status": response.status_code,
+        "uploadid": uploadid,
+        "fileid": fileid,
+        "url": url
+    }
+
+
+def smartsend(subject, data, nats_url=DEFAULT_NATS_URL, fileserver_url=DEFAULT_FILESERVER_URL,
+              fileserver_upload_handler=plik_oneshot_upload, size_threshold=DEFAULT_SIZE_THRESHOLD,
+              correlation_id=None, msg_purpose="chat", sender_name="NATSBridge",
+              receiver_name="", receiver_id="", reply_to="", reply_to_msg_id="", is_publish=True):
+    """Send data either directly via NATS or via a fileserver URL, depending on payload size.
+    
+    This function intelligently routes data delivery based on payload size relative to a threshold.
+    If the serialized payload is smaller than `size_threshold`, it encodes the data as Base64 and 
+    publishes directly over NATS. Otherwise, it uploads the data to a fileserver and publishes 
+    only the download URL over NATS.
+    
+    Args:
+        subject: NATS subject to publish the message to
+        data: List of (dataname, data, type) tuples to send
+        nats_url: URL of the NATS server
+        fileserver_url: URL of the HTTP file server
+        fileserver_upload_handler: Function to handle fileserver uploads
+        size_threshold: Threshold in bytes separating direct vs link transport
+        correlation_id: Optional correlation ID for tracing
+        msg_purpose: Purpose of the message
+        sender_name: Name of the sender
+        receiver_name: Name of the receiver
+        receiver_id: UUID of the receiver
+        reply_to: Topic to reply to
+        reply_to_msg_id: Message ID this message is replying to
+        is_publish: Whether to automatically publish the message to NATS (default: True)
+    
+    Returns:
+        tuple: (env, env_json_str) where:
+            - env: MessageEnvelope object with all metadata and payloads
+            - env_json_str: JSON string representation of the envelope for publishing
+    """
+    # Generate correlation ID if not provided
+    cid = correlation_id if correlation_id else str(uuid.uuid4())
+    
+    log_trace(cid, "Starting smartsend for subject: {}".format(subject))
+    
+    # Generate message metadata
+    msg_id = str(uuid.uuid4())
+    
+    # Process each payload in the list
+    payloads = []
+    
+    for dataname, payload_data, payload_type in data:
+        # Serialize data based on type
+        payload_bytes = _serialize_data(payload_data, payload_type)
+        
+        payload_size = len(payload_bytes)
+        log_trace(cid, "Serialized payload '{}' (type: {}) size: {} bytes".format(
+            dataname, payload_type, payload_size))
+        
+        # Decision: Direct vs Link
+        if payload_size < size_threshold:
+            # Direct path - Base64 encode and send via NATS
+            payload_b64 = _serialize_data(payload_bytes, "binary")  # Already bytes
+            # Convert to base64 string for JSON
+            import ubinascii
+            payload_b64_str = ubinascii.b2a_base64(payload_bytes).decode('utf-8').strip()
+            
+            log_trace(cid, "Using direct transport for {} bytes".format(payload_size))
+            
+            # Create MessagePayload for direct transport
+            payload = MessagePayload(
+                payload_b64_str,
+                payload_type,
+                id=str(uuid.uuid4()),
+                dataname=dataname,
+                transport="direct",
+                encoding="base64",
+                size=payload_size,
+                metadata={"payload_bytes": payload_size}
+            )
+            payloads.append(payload)
+        else:
+            # Link path - Upload to HTTP server, send URL via NATS
+            log_trace(cid, "Using link transport, uploading to fileserver")
+            
+            # Upload to HTTP server
+            response = fileserver_upload_handler(fileserver_url, dataname, payload_bytes)
+            
+            if response["status"] != 200:
+                raise Exception("Failed to upload data to fileserver: {}".format(response["status"]))
+            
+            url = response["url"]
+            log_trace(cid, "Uploaded to URL: {}".format(url))
+            
+            # Create MessagePayload for link transport
+            payload = MessagePayload(
+                url,
+                payload_type,
+                id=str(uuid.uuid4()),
+                dataname=dataname,
+                transport="link",
+                encoding="none",
+                size=payload_size,
+                metadata={}
+            )
+            payloads.append(payload)
+    
+    # Create MessageEnvelope with all payloads
+    env = MessageEnvelope(
+        subject,
+        payloads,
+        correlation_id=cid,
+        msg_id=msg_id,
+        msg_purpose=msg_purpose,
+        sender_name=sender_name,
+        sender_id=str(uuid.uuid4()),
+        receiver_name=receiver_name,
+        receiver_id=receiver_id,
+        reply_to=reply_to,
+        reply_to_msg_id=reply_to_msg_id,
+        broker_url=nats_url,
+        metadata={}
+    )
+    
+    msg_json = env.to_json()
+    
+    # Publish to NATS if is_publish is True
+    if is_publish:
+        nats_conn = NATSConnection(nats_url)
+        nats_conn.connect()
+        nats_conn.publish(subject, msg_json)
+        nats_conn.close()
+    
+    # Return tuple of (envelope, json_string) for both direct and link transport
+    return (env, msg_json)
+
+
+def smartreceive(msg, fileserver_download_handler=_fetch_with_backoff, max_retries=5,
+                  base_delay=100, max_delay=5000):
+    """Receive and process messages from NATS.
+    
+    This function processes incoming NATS messages, handling both direct transport
+    (base64 decoded payloads) and link transport (URL-based payloads).
+    
+    Args:
+        msg: NATS message to process (dict with payload data)
+        fileserver_download_handler: Function to handle downloading data from file server URLs
+        max_retries: Maximum retry attempts for fetching URL
+        base_delay: Initial delay for exponential backoff in ms
+        max_delay: Maximum delay for exponential backoff in ms
+    
+    Returns:
+        dict: Envelope dictionary with metadata and 'payloads' field containing list of (dataname, data, type) tuples
+    """
+    # Parse the JSON envelope
+    json_data = msg if isinstance(msg, dict) else json.loads(msg)
+    log_trace(json_data.get("correlationId", ""), "Processing received message")
+    
+    # Process all payloads in the envelope
+    payloads_list = []
+    
+    # Get number of payloads
+    num_payloads = len(json_data.get("payloads", []))
+    
+    for i in range(num_payloads):
+        payload = json_data["payloads"][i]
+        transport = payload.get("transport", "")
+        dataname = payload.get("dataname", "")
+        
+        if transport == "direct":
+            log_trace(json_data.get("correlationId", ""), 
+                     "Direct transport - decoding payload '{}'".format(dataname))
+            
+            # Extract base64 payload from the payload
+            payload_b64 = payload.get("data", "")
+            
+            # Decode Base64 payload
+            import ubinascii
+            payload_bytes = ubinascii.a2b_base64(payload_b64.encode('utf-8'))
+            
+            # Deserialize based on type
+            data_type = payload.get("type", "")
+            data = _deserialize_data(payload_bytes, data_type, json_data.get("correlationId", ""))
+            
+            payloads_list.append((dataname, data, data_type))
+            
+        elif transport == "link":
+            # Extract download URL from the payload
+            url = payload.get("data", "")
+            log_trace(json_data.get("correlationId", ""),
+                      "Link transport - fetching '{}' from URL: {}".format(dataname, url))
+            
+            # Fetch with exponential backoff
+            downloaded_data = fileserver_download_handler(
+                url, max_retries, base_delay, max_delay, json_data.get("correlationId", "")
+            )
+            
+            # Deserialize based on type
+            data_type = payload.get("type", "")
+            data = _deserialize_data(downloaded_data, data_type, json_data.get("correlationId", ""))
+            
+            payloads_list.append((dataname, data, data_type))
+            
+        else:
+            raise ValueError("Unknown transport type for payload '{}': {}".format(dataname, transport))
+    
+    # Replace payloads field with the processed list of (dataname, data, type) tuples
+    json_data["payloads"] = payloads_list
+    
+    return json_data
+
+
+# Utility functions
+def generate_uuid():
+    """Generate a UUID string."""
+    return str(uuid.uuid4())
+
+
+def get_timestamp():
+    """Get current timestamp in ISO format."""
+    return time.strftime("%Y-%m-%dT%H:%M:%S", time.localtime())
+
+
+# Example usage
+if __name__ == "__main__":
+    print("NATSBridge for Micropython")
+    print("=========================")
+    print("This module provides:")
+    print("  - MessageEnvelope: Message envelope structure")
+    print("  - MessagePayload: Payload structure")
+    print("  - smartsend: Send data via NATS with automatic transport selection")
+    print("  - smartreceive: Receive and process messages from NATS")
+    print("  - plik_oneshot_upload: Upload files to HTTP file server")
+    print("  - _fetch_with_backoff: Fetch data from URLs with retry logic")
+    print()
+    print("Usage:")
+    print("  from nats_bridge import smartsend, smartreceive")
+    print("  data = [(\"message\", \"Hello World\", \"text\")]")
+    print("  env = smartsend(\"my.subject\", data)")
+    print()
+    print("  # On receiver:")
+    print("  payloads = smartreceive(msg)")
+    print("  for dataname, data, type in payloads:")
+    print("      print(f\"Received {dataname} of type {type}: {data}\")")

test/scenario1_command_control.jl

@@ -1,67 +0,0 @@
-#!/usr/bin/env julia
-# Scenario 1: Command & Control (Small JSON)
-# Tests small JSON payloads (< 1MB) sent directly via NATS
-
-using NATS
-using JSON3
-using UUIDs
-
-# Include the bridge module
-include("../src/julia_bridge.jl")
-using .BiDirectionalBridge
-
-# Configuration
-const CONTROL_SUBJECT = "control"
-const RESPONSE_SUBJECT = "control_response"
-const NATS_URL = "nats://localhost:4222"
-
-# Create correlation ID for tracing
-correlation_id = string(uuid4())
-
-# Receiver: Listen for control commands
-function start_control_listener()
-    conn = NATS.Connection(NATS_URL)
-    try
-        NATS.subscribe(conn, CONTROL_SUBJECT) do msg
-            log_trace(msg.data)
-            
-            # Parse the envelope
-            env = MessageEnvelope(String(msg.data))
-            
-            # Parse JSON payload
-            config = JSON3.read(env.payload)
-            
-            # Execute simulation with parameters
-            step_size = config.step_size
-            iterations = config.iterations
-            
-            # Simulate processing
-            sleep(0.1)  # Simulate some work
-            
-            # Send acknowledgment
-            response = Dict(
-                "status" => "Running",
-                "correlation_id" => env.correlation_id,
-                "step_size" => step_size,
-                "iterations" => iterations
-            )
-            
-            NATS.publish(conn, RESPONSE_SUBJECT, JSON3.stringify(response))
-            log_trace("Sent response: $(JSON3.stringify(response))")
-        end
-        
-        # Keep listening for 5 seconds
-        sleep(5)
-    finally
-        NATS.close(conn)
-    end
-end
-
-# Helper: Log with correlation ID
-function log_trace(message)
-    timestamp = Dates.now()
-    println("[$timestamp] [Correlation: $correlation_id] $message")
-end
-
-# Run the listener
-start_control_listener()

test/scenario1_command_control.js

@@ -1,34 +0,0 @@
-#!/usr/bin/env node
-// Scenario 1: Command & Control (Small JSON)
-// Tests small JSON payloads (< 1MB) sent directly via NATS
-
-const { SmartSend } = require('../js_bridge');
-
-// Configuration
-const CONTROL_SUBJECT = "control";
-const NATS_URL = "nats://localhost:4222";
-
-// Create correlation ID for tracing
-const correlationId = require('uuid').v4();
-
-// Sender: Send control command to Julia
-async function sendControlCommand() {
-    const config = {
-        step_size: 0.01,
-        iterations: 1000
-    };
-
-    // Send via SmartSend with type="json"
-    const env = await SmartSend(
-        CONTROL_SUBJECT,
-        config,
-        "json",
-        { correlationId }
-    );
-
-    console.log(`Sent control command with correlation_id: ${correlationId}`);
-    console.log(`Envelope: ${JSON.stringify(env, null, 2)}`);
-}
-
-// Run the sender
-sendControlCommand().catch(console.error);

test/scenario2_large_table.jl

@@ -1,66 +0,0 @@
-#!/usr/bin/env julia
-# Scenario 2: Deep Dive Analysis (Large Arrow Table)
-# Tests large Arrow tables (> 1MB) sent via HTTP fileserver
-
-using NATS
-using Arrow
-using DataFrames
-using JSON3
-using UUIDs
-
-# Include the bridge module
-include("../src/julia_bridge.jl")
-using .BiDirectionalBridge
-
-# Configuration
-const ANALYSIS_SUBJECT = "analysis_results"
-const RESPONSE_SUBJECT = "analysis_response"
-const NATS_URL = "nats://localhost:4222"
-
-# Create correlation ID for tracing
-correlation_id = string(uuid4())
-
-# Receiver: Listen for analysis results
-function start_analysis_listener()
-    conn = NATS.Connection(NATS_URL)
-    try
-        NATS.subscribe(conn, ANALYSIS_SUBJECT) do msg
-            log_trace("Received message from $(msg.subject)")
-            
-            # Parse the envelope
-            env = MessageEnvelope(String(msg.data))
-            
-            # Use SmartReceive to handle the data
-            result = SmartReceive(msg)
-            
-            # Process the data based on type
-            if result.envelope.type == "table"
-                df = result.data
-                log_trace("Received DataFrame with $(nrows(df)) rows")
-                log_trace("DataFrame columns: $(names(df))")
-                
-                # Send acknowledgment
-                response = Dict(
-                    "status" => "Processed",
-                    "correlation_id" => env.correlation_id,
-                    "row_count" => nrows(df)
-                )
-                NATS.publish(conn, RESPONSE_SUBJECT, JSON3.stringify(response))
-            end
-        end
-        
-        # Keep listening for 10 seconds
-        sleep(10)
-    finally
-        NATS.close(conn)
-    end
-end
-
-# Helper: Log with correlation ID
-function log_trace(message)
-    timestamp = Dates.now()
-    println("[$timestamp] [Correlation: $correlation_id] $message")
-end
-
-# Run the listener
-start_analysis_listener()

test/scenario2_large_table.js

@@ -1,54 +0,0 @@
-#!/usr/bin/env node
-// Scenario 2: Deep Dive Analysis (Large Arrow Table)
-// Tests large Arrow tables (> 1MB) sent via HTTP fileserver
-
-const { SmartSend } = require('../js_bridge');
-
-// Configuration
-const ANALYSIS_SUBJECT = "analysis_results";
-const NATS_URL = "nats://localhost:4222";
-
-// Create correlation ID for tracing
-const correlationId = require('uuid').v4();
-
-// Sender: Send large Arrow table to Julia
-async function sendLargeTable() {
-    // Create a large DataFrame-like structure (10 million rows)
-    // For testing, we'll create a smaller but still large table
-    const numRows = 1000000; // 1 million rows
-    
-    const data = {
-        id: Array.from({ length: numRows }, (_, i) => i + 1),
-        value: Array.from({ length: numRows }, () => Math.random()),
-        category: Array.from({ length: numRows }, () => ['A', 'B', 'C'][Math.floor(Math.random() * 3)])
-    };
-    
-    // Convert to Arrow Table
-    const { Table, Vector, RecordBatch } = require('apache-arrow');
-    
-    const idVector = Vector.from(data.id);
-    const valueVector = Vector.from(data.value);
-    const categoryVector = Vector.from(data.category);
-    
-    const table = Table.from({
-        id: idVector,
-        value: valueVector,
-        category: categoryVector
-    });
-    
-    // Send via SmartSend with type="table"
-    const env = await SmartSend(
-        ANALYSIS_SUBJECT,
-        table,
-        "table",
-        { correlationId }
-    );
-    
-    console.log(`Sent large table with ${numRows} rows`);
-    console.log(`Correlation ID: ${correlationId}`);
-    console.log(`Transport: ${env.transport}`);
-    console.log(`URL: ${env.url || 'N/A'}`);
-}
-
-// Run the sender
-sendLargeTable().catch(console.error);

test/test_js_dict_receiver.js

@@ -0,0 +1,80 @@
+#!/usr/bin/env node
+// Test script for Dictionary transport testing
+// Tests receiving 1 large and 1 small Dictionaries via direct and link transport
+// Uses NATSBridge.js smartreceive with "dictionary" type
+
+const { smartreceive, log_trace } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_dict_test";
+const NATS_URL = "nats.yiem.cc";
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] ${message}`);
+}
+
+// Receiver: Listen for messages and verify Dictionary handling
+async function test_dict_receive() {
+    // Connect to NATS
+    const { connect } = require('nats');
+    const nc = await connect({ servers: [NATS_URL] });
+    
+    // Subscribe to the subject
+    const sub = nc.subscribe(SUBJECT);
+    
+    for await (const msg of sub) {
+        log_trace(`Received message on ${msg.subject}`);
+        
+        // Use NATSBridge.smartreceive to handle the data
+        const result = await smartreceive(
+            msg,
+            {
+                maxRetries: 5,
+                baseDelay: 100,
+                maxDelay: 5000
+            }
+        );
+        
+        // Result is an envelope dictionary with payloads field
+        // Access payloads with result.payloads
+        for (const { dataname, data, type } of result.payloads) {
+            if (typeof data === 'object' && data !== null && !Array.isArray(data)) {
+                log_trace(`Received Dictionary '${dataname}' of type ${type}`);
+                
+                // Display dictionary contents
+                console.log("  Contents:");
+                for (const [key, value] of Object.entries(data)) {
+                    console.log(`    ${key} => ${value}`);
+                }
+                
+                // Save to JSON file
+                const fs = require('fs');
+                const output_path = `./received_${dataname}.json`;
+                const json_str = JSON.stringify(data, null, 2);
+                fs.writeFileSync(output_path, json_str);
+                log_trace(`Saved Dictionary to ${output_path}`);
+            } else {
+                log_trace(`Received unexpected data type for '${dataname}': ${typeof data}`);
+            }
+        }
+    }
+    
+    // Keep listening for 10 seconds
+    setTimeout(() => {
+        nc.close();
+        process.exit(0);
+    }, 120000);
+}
+
+// Run the test
+console.log("Starting Dictionary transport test...");
+console.log("Note: This receiver will wait for messages from the sender.");
+console.log("Run test_js_to_js_dict_sender.js first to send test data.");
+
+// Run receiver
+console.log("testing smartreceive");
+test_dict_receive();
+
+console.log("Test completed.");

test/test_js_dict_sender.js

@@ -0,0 +1,165 @@
+#!/usr/bin/env node
+// Test script for Dictionary transport testing
+// Tests sending 1 large and 1 small Dictionaries via direct and link transport
+// Uses NATSBridge.js smartsend with "dictionary" type
+
+const { smartsend, uuid4, log_trace } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_dict_test";
+const NATS_URL = "nats.yiem.cc";
+const FILESERVER_URL = "http://192.168.88.104:8080";
+
+// Create correlation ID for tracing
+const correlation_id = uuid4();
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] [Correlation: ${correlation_id}] ${message}`);
+}
+
+// File upload handler for plik server
+async function plik_upload_handler(fileserver_url, dataname, data, correlation_id) {
+    // Get upload ID
+    const url_getUploadID = `${fileserver_url}/upload`;
+    const headers = {
+        "Content-Type": "application/json"
+    };
+    const body = JSON.stringify({ OneShot: true });
+    
+    let response = await fetch(url_getUploadID, {
+        method: "POST",
+        headers: headers,
+        body: body
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to get upload ID: ${response.status} ${response.statusText}`);
+    }
+    
+    const responseJson = await response.json();
+    const uploadid = responseJson.id;
+    const uploadtoken = responseJson.uploadToken;
+    
+    // Upload file
+    const formData = new FormData();
+    const blob = new Blob([data], { type: "application/octet-stream" });
+    formData.append("file", blob, dataname);
+    
+    response = await fetch(`${fileserver_url}/file/${uploadid}`, {
+        method: "POST",
+        headers: {
+            "X-UploadToken": uploadtoken
+        },
+        body: formData
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to upload file: ${response.status} ${response.statusText}`);
+    }
+    
+    const fileResponseJson = await response.json();
+    const fileid = fileResponseJson.id;
+    
+    const url = `${fileserver_url}/file/${uploadid}/${fileid}/${encodeURIComponent(dataname)}`;
+    
+    return {
+        status: response.status,
+        uploadid: uploadid,
+        fileid: fileid,
+        url: url
+    };
+}
+
+// Sender: Send Dictionaries via smartsend
+async function test_dict_send() {
+    // Create a small Dictionary (will use direct transport)
+    const small_dict = {
+        name: "Alice",
+        age: 30,
+        scores: [95, 88, 92],
+        metadata: {
+            height: 155,
+            weight: 55
+        }
+    };
+    
+    // Create a large Dictionary (will use link transport if > 1MB)
+    const large_dict_ids = [];
+    const large_dict_names = [];
+    const large_dict_scores = [];
+    const large_dict_categories = [];
+    
+    for (let i = 0; i < 50000; i++) {
+        large_dict_ids.push(i + 1);
+        large_dict_names.push(`User_${i}`);
+        large_dict_scores.push(Math.floor(Math.random() * 100) + 1);
+        large_dict_categories.push(`Category_${Math.floor(Math.random() * 10) + 1}`);
+    }
+    
+    const large_dict = {
+        ids: large_dict_ids,
+        names: large_dict_names,
+        scores: large_dict_scores,
+        categories: large_dict_categories,
+        metadata: {
+            source: "test_generator",
+            timestamp: new Date().toISOString()
+        }
+    };
+    
+    // Test data 1: small Dictionary
+    const data1 = { dataname: "small_dict", data: small_dict, type: "dictionary" };
+    
+    // Test data 2: large Dictionary
+    const data2 = { dataname: "large_dict", data: large_dict, type: "dictionary" };
+    
+    // Use smartsend with dictionary type
+    // For small Dictionary: will use direct transport (JSON encoded)
+    // For large Dictionary: will use link transport (uploaded to fileserver)
+    const { env, env_json_str } = await smartsend(
+        SUBJECT,
+        [data1, data2],
+        {
+            natsUrl: NATS_URL,
+            fileserverUrl: FILESERVER_URL,
+            fileserverUploadHandler: plik_upload_handler,
+            sizeThreshold: 1_000_000,
+            correlationId: correlation_id,
+            msgPurpose: "chat",
+            senderName: "dict_sender",
+            receiverName: "",
+            receiverId: "",
+            replyTo: "",
+            replyToMsgId: "",
+            isPublish: true  // Publish the message to NATS
+        }
+    );
+    
+    log_trace(`Sent message with ${env.payloads.length} payloads`);
+    
+    // Log transport type for each payload
+    for (let i = 0; i < env.payloads.length; i++) {
+        const payload = env.payloads[i];
+        log_trace(`Payload ${i + 1} ('${payload.dataname}'):`);
+        log_trace(`  Transport: ${payload.transport}`);
+        log_trace(`  Type: ${payload.type}`);
+        log_trace(`  Size: ${payload.size} bytes`);
+        log_trace(`  Encoding: ${payload.encoding}`);
+        
+        if (payload.transport === "link") {
+            log_trace(`  URL: ${payload.data}`);
+        }
+    }
+}
+
+// Run the test
+console.log("Starting Dictionary transport test...");
+console.log(`Correlation ID: ${correlation_id}`);
+
+// Run sender
+console.log("start smartsend for dictionaries");
+test_dict_send();
+
+console.log("Test completed.");

test/test_js_file_receiver.js

@@ -0,0 +1,71 @@
+#!/usr/bin/env node
+// Test script for large payload testing using binary transport
+// Tests receiving a large file (> 1MB) via smartsend with binary type
+
+const { smartreceive, log_trace } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_test";
+const NATS_URL = "nats.yiem.cc";
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] ${message}`);
+}
+
+// Receiver: Listen for messages and verify large payload handling
+async function test_large_binary_receive() {
+    // Connect to NATS
+    const { connect } = require('nats');
+    const nc = await connect({ servers: [NATS_URL] });
+    
+    // Subscribe to the subject
+    const sub = nc.subscribe(SUBJECT);
+    
+    for await (const msg of sub) {
+        log_trace(`Received message on ${msg.subject}`);
+        
+        // Use NATSBridge.smartreceive to handle the data
+        const result = await smartreceive(
+            msg,
+            {
+                maxRetries: 5,
+                baseDelay: 100,
+                maxDelay: 5000
+            }
+        );
+        
+        // Result is an envelope dictionary with payloads field
+        // Access payloads with result.payloads
+        for (const { dataname, data, type } of result.payloads) {
+            if (data instanceof Uint8Array || Array.isArray(data)) {
+                const file_size = data.length;
+                log_trace(`Received ${file_size} bytes of binary data for '${dataname}' of type ${type}`);
+                
+                // Save received data to a test file
+                const fs = require('fs');
+                const output_path = `./new_${dataname}`;
+                fs.writeFileSync(output_path, Buffer.from(data));
+                log_trace(`Saved received data to ${output_path}`);
+            } else {
+                log_trace(`Received unexpected data type for '${dataname}': ${typeof data}`);
+            }
+        }
+    }
+    
+    // Keep listening for 10 seconds
+    setTimeout(() => {
+        nc.close();
+        process.exit(0);
+    }, 120000);
+}
+
+// Run the test
+console.log("Starting large binary payload test...");
+
+// Run receiver
+console.log("testing smartreceive");
+test_large_binary_receive();
+
+console.log("Test completed.");

test/test_js_file_sender.js

@@ -0,0 +1,144 @@
+#!/usr/bin/env node
+// Test script for large payload testing using binary transport
+// Tests sending a large file (> 1MB) via smartsend with binary type
+
+const { smartsend, uuid4, log_trace } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_test";
+const NATS_URL = "nats.yiem.cc";
+const FILESERVER_URL = "http://192.168.88.104:8080";
+
+// Create correlation ID for tracing
+const correlation_id = uuid4();
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] [Correlation: ${correlation_id}] ${message}`);
+}
+
+// File upload handler for plik server
+async function plik_upload_handler(fileserver_url, dataname, data, correlation_id) {
+    log_trace(correlation_id, `Uploading ${dataname} to fileserver: ${fileserver_url}`);
+    
+    // Step 1: Get upload ID and token
+    const url_getUploadID = `${fileserver_url}/upload`;
+    const headers = {
+        "Content-Type": "application/json"
+    };
+    const body = JSON.stringify({ OneShot: true });
+    
+    let response = await fetch(url_getUploadID, {
+        method: "POST",
+        headers: headers,
+        body: body
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to get upload ID: ${response.status} ${response.statusText}`);
+    }
+    
+    const responseJson = await response.json();
+    const uploadid = responseJson.id;
+    const uploadtoken = responseJson.uploadToken;
+    
+    // Step 2: Upload file data
+    const url_upload = `${fileserver_url}/file/${uploadid}`;
+    
+    // Create multipart form data
+    const formData = new FormData();
+    const blob = new Blob([data], { type: "application/octet-stream" });
+    formData.append("file", blob, dataname);
+    
+    response = await fetch(url_upload, {
+        method: "POST",
+        headers: {
+            "X-UploadToken": uploadtoken
+        },
+        body: formData
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to upload file: ${response.status} ${response.statusText}`);
+    }
+    
+    const fileResponseJson = await response.json();
+    const fileid = fileResponseJson.id;
+    
+    // Build the download URL
+    const url = `${fileserver_url}/file/${uploadid}/${fileid}/${encodeURIComponent(dataname)}`;
+    
+    log_trace(correlation_id, `Uploaded to URL: ${url}`);
+    
+    return {
+        status: response.status,
+        uploadid: uploadid,
+        fileid: fileid,
+        url: url
+    };
+}
+
+// Sender: Send large binary file via smartsend
+async function test_large_binary_send() {
+    // Read the large file as binary data
+    const fs = require('fs');
+    
+    // Test data 1
+    const file_path1 = './testFile_large.zip';
+    const file_data1 = fs.readFileSync(file_path1);
+    const filename1 = 'testFile_large.zip';
+    const data1 = { dataname: filename1, data: file_data1, type: "binary" };
+    
+    // Test data 2
+    const file_path2 = './testFile_small.zip';
+    const file_data2 = fs.readFileSync(file_path2);
+    const filename2 = 'testFile_small.zip';
+    const data2 = { dataname: filename2, data: file_data2, type: "binary" };
+    
+    // Use smartsend with binary type - will automatically use link transport
+    // if file size exceeds the threshold (1MB by default)
+    const { env, env_json_str } = await smartsend(
+        SUBJECT,
+        [data1, data2],
+        {
+            natsUrl: NATS_URL,
+            fileserverUrl: FILESERVER_URL,
+            fileserverUploadHandler: plik_upload_handler,
+            sizeThreshold: 1_000_000,
+            correlationId: correlation_id,
+            msgPurpose: "chat",
+            senderName: "sender",
+            receiverName: "",
+            receiverId: "",
+            replyTo: "",
+            replyToMsgId: "",
+            isPublish: true  // Publish the message to NATS
+        }
+    );
+    
+    log_trace(`Sent message with transport: ${env.payloads[0].transport}`);
+    log_trace(`Envelope type: ${env.payloads[0].type}`);
+    
+    // Check if link transport was used
+    if (env.payloads[0].transport === "link") {
+        log_trace("Using link transport - file uploaded to HTTP server");
+        log_trace(`URL: ${env.payloads[0].data}`);
+    } else {
+        log_trace("Using direct transport - payload sent via NATS");
+    }
+}
+
+// Run the test
+console.log("Starting large binary payload test...");
+console.log(`Correlation ID: ${correlation_id}`);
+
+// Run sender first
+console.log("start smartsend");
+test_large_binary_send();
+
+// Run receiver
+// console.log("testing smartreceive");
+// test_large_binary_receive();
+
+console.log("Test completed.");

test/test_js_mix_payload_sender.js

@@ -0,0 +1,277 @@
+#!/usr/bin/env node
+// Test script for mixed-content message testing
+// Tests sending a mix of text, json, table, image, audio, video, and binary data
+// from JavaScript serviceA to JavaScript serviceB using NATSBridge.js smartsend
+//
+// This test demonstrates that any combination and any number of mixed content
+// can be sent and received correctly.
+
+const { smartsend, uuid4, log_trace, _serialize_data } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_mix_test";
+const NATS_URL = "nats.yiem.cc";
+const FILESERVER_URL = "http://192.168.88.104:8080";
+
+// Create correlation ID for tracing
+const correlation_id = uuid4();
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] [Correlation: ${correlation_id}] ${message}`);
+}
+
+// File upload handler for plik server
+async function plik_upload_handler(fileserver_url, dataname, data, correlation_id) {
+    log_trace(correlation_id, `Uploading ${dataname} to fileserver: ${fileserver_url}`);
+    
+    // Step 1: Get upload ID and token
+    const url_getUploadID = `${fileserver_url}/upload`;
+    const headers = {
+        "Content-Type": "application/json"
+    };
+    const body = JSON.stringify({ OneShot: true });
+    
+    let response = await fetch(url_getUploadID, {
+        method: "POST",
+        headers: headers,
+        body: body
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to get upload ID: ${response.status} ${response.statusText}`);
+    }
+    
+    const responseJson = await response.json();
+    const uploadid = responseJson.id;
+    const uploadtoken = responseJson.uploadToken;
+    
+    // Step 2: Upload file data
+    const url_upload = `${fileserver_url}/file/${uploadid}`;
+    
+    // Create multipart form data
+    const formData = new FormData();
+    const blob = new Blob([data], { type: "application/octet-stream" });
+    formData.append("file", blob, dataname);
+    
+    response = await fetch(url_upload, {
+        method: "POST",
+        headers: {
+            "X-UploadToken": uploadtoken
+        },
+        body: formData
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to upload file: ${response.status} ${response.statusText}`);
+    }
+    
+    const fileResponseJson = await response.json();
+    const fileid = fileResponseJson.id;
+    
+    // Build the download URL
+    const url = `${fileserver_url}/file/${uploadid}/${fileid}/${encodeURIComponent(dataname)}`;
+    
+    log_trace(correlation_id, `Uploaded to URL: ${url}`);
+    
+    return {
+        status: response.status,
+        uploadid: uploadid,
+        fileid: fileid,
+        url: url
+    };
+}
+
+// Helper: Create sample data for each type
+function create_sample_data() {
+    // Text data (small - direct transport)
+    const text_data = "Hello! This is a test chat message. 🎉\nHow are you doing today? 😊";
+    
+    // Dictionary/JSON data (medium - could be direct or link)
+    const dict_data = {
+        type: "chat",
+        sender: "serviceA",
+        receiver: "serviceB",
+        metadata: {
+            timestamp: new Date().toISOString(),
+            priority: "high",
+            tags: ["urgent", "chat", "test"]
+        },
+        content: {
+            text: "This is a JSON-formatted chat message with nested structure.",
+            format: "markdown",
+            mentions: ["user1", "user2"]
+        }
+    };
+    
+    // Table data (small - direct transport) - NOT IMPLEMENTED (requires apache-arrow)
+    // const table_data_small = {...};
+    
+    // Table data (large - link transport) - NOT IMPLEMENTED (requires apache-arrow)
+    // const table_data_large = {...};
+    
+    // Image data (small binary - direct transport)
+    // Create a simple 10x10 pixel PNG-like data
+    const image_width = 10;
+    const image_height = 10;
+    let image_data = new Uint8Array(128);  // PNG header + pixel data
+    // PNG header
+    image_data[0] = 0x89;
+    image_data[1] = 0x50;
+    image_data[2] = 0x4E;
+    image_data[3] = 0x47;
+    image_data[4] = 0x0D;
+    image_data[5] = 0x0A;
+    image_data[6] = 0x1A;
+    image_data[7] = 0x0A;
+    // Simple RGB data (10*10*3 = 300 bytes)
+    for (let i = 0; i < 300; i++) {
+        image_data[i + 8] = 0xFF;  // Red pixel
+    }
+    
+    // Image data (large - link transport)
+    const large_image_width = 500;
+    const large_image_height = 1000;
+    const large_image_data = new Uint8Array(large_image_width * large_image_height * 3 + 8);
+    // PNG header
+    large_image_data[0] = 0x89;
+    large_image_data[1] = 0x50;
+    large_image_data[2] = 0x4E;
+    large_image_data[3] = 0x47;
+    large_image_data[4] = 0x0D;
+    large_image_data[5] = 0x0A;
+    large_image_data[6] = 0x1A;
+    large_image_data[7] = 0x0A;
+    // Random RGB data
+    for (let i = 0; i < large_image_width * large_image_height * 3; i++) {
+        large_image_data[i + 8] = Math.floor(Math.random() * 255);
+    }
+    
+    // Audio data (small binary - direct transport)
+    const audio_data = new Uint8Array(100);
+    for (let i = 0; i < 100; i++) {
+        audio_data[i] = Math.floor(Math.random() * 255);
+    }
+    
+    // Audio data (large - link transport)
+    const large_audio_data = new Uint8Array(1_500_000);
+    for (let i = 0; i < 1_500_000; i++) {
+        large_audio_data[i] = Math.floor(Math.random() * 255);
+    }
+    
+    // Video data (small binary - direct transport)
+    const video_data = new Uint8Array(150);
+    for (let i = 0; i < 150; i++) {
+        video_data[i] = Math.floor(Math.random() * 255);
+    }
+    
+    // Video data (large - link transport)
+    const large_video_data = new Uint8Array(1_500_000);
+    for (let i = 0; i < 1_500_000; i++) {
+        large_video_data[i] = Math.floor(Math.random() * 255);
+    }
+    
+    // Binary data (small - direct transport)
+    const binary_data = new Uint8Array(200);
+    for (let i = 0; i < 200; i++) {
+        binary_data[i] = Math.floor(Math.random() * 255);
+    }
+    
+    // Binary data (large - link transport)
+    const large_binary_data = new Uint8Array(1_500_000);
+    for (let i = 0; i < 1_500_000; i++) {
+        large_binary_data[i] = Math.floor(Math.random() * 255);
+    }
+    
+    return {
+        text_data,
+        dict_data,
+        // table_data_small,
+        // table_data_large,
+        image_data,
+        large_image_data,
+        audio_data,
+        large_audio_data,
+        video_data,
+        large_video_data,
+        binary_data,
+        large_binary_data
+    };
+}
+
+// Sender: Send mixed content via smartsend
+async function test_mix_send() {
+    // Create sample data
+    const { text_data, dict_data, image_data, large_image_data, audio_data, large_audio_data, video_data, large_video_data, binary_data, large_binary_data } = create_sample_data();
+    
+    // Create payloads list - mixed content with both small and large data
+    // Small data uses direct transport, large data uses link transport
+    const payloads = [
+        // Small data (direct transport) - text, dictionary
+        { dataname: "chat_text", data: text_data, type: "text" },
+        { dataname: "chat_json", data: dict_data, type: "dictionary" },
+        // { dataname: "chat_table_small", data: table_data_small, type: "table" },
+        
+        // Large data (link transport) - large image, large audio, large video, large binary
+        // { dataname: "chat_table_large", data: table_data_large, type: "table" },
+        { dataname: "user_image_large", data: large_image_data, type: "image" },
+        { dataname: "audio_clip_large", data: large_audio_data, type: "audio" },
+        { dataname: "video_clip_large", data: large_video_data, type: "video" },
+        { dataname: "binary_file_large", data: large_binary_data, type: "binary" }
+    ];
+    
+    // Use smartsend with mixed content
+    const { env, env_json_str } = await smartsend(
+        SUBJECT,
+        payloads,
+        {
+            natsUrl: NATS_URL,
+            fileserverUrl: FILESERVER_URL,
+            fileserverUploadHandler: plik_upload_handler,
+            sizeThreshold: 1_000_000,
+            correlationId: correlation_id,
+            msgPurpose: "chat",
+            senderName: "mix_sender",
+            receiverName: "",
+            receiverId: "",
+            replyTo: "",
+            replyToMsgId: "",
+            isPublish: true  // Publish the message to NATS
+        }
+    );
+    
+    log_trace(`Sent message with ${env.payloads.length} payloads`);
+    
+    // Log transport type for each payload
+    for (let i = 0; i < env.payloads.length; i++) {
+        const payload = env.payloads[i];
+        log_trace(`Payload ${i + 1} ('${payload.dataname}'):`);
+        log_trace(`  Transport: ${payload.transport}`);
+        log_trace(`  Type: ${payload.type}`);
+        log_trace(`  Size: ${payload.size} bytes`);
+        log_trace(`  Encoding: ${payload.encoding}`);
+        
+        if (payload.transport === "link") {
+            log_trace(`  URL: ${payload.data}`);
+        }
+    }
+    
+    // Summary
+    console.log("\n--- Transport Summary ---");
+    const direct_count = env.payloads.filter(p => p.transport === "direct").length;
+    const link_count = env.payloads.filter(p => p.transport === "link").length;
+    log_trace(`Direct transport: ${direct_count} payloads`);
+    log_trace(`Link transport: ${link_count} payloads`);
+}
+
+// Run the test
+console.log("Starting mixed-content transport test...");
+console.log(`Correlation ID: ${correlation_id}`);
+
+// Run sender
+console.log("start smartsend for mixed content");
+test_mix_send();
+
+console.log("\nTest completed.");
+console.log("Note: Run test_js_to_js_mix_receiver.js to receive the messages.");

test/test_js_mix_payloads_receiver.js

@@ -0,0 +1,173 @@
+#!/usr/bin/env node
+// Test script for mixed-content message testing
+// Tests receiving a mix of text, json, table, image, audio, video, and binary data
+// from JavaScript serviceA to JavaScript serviceB using NATSBridge.js smartreceive
+//
+// This test demonstrates that any combination and any number of mixed content
+// can be sent and received correctly.
+
+const { smartreceive, log_trace } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_mix_test";
+const NATS_URL = "nats.yiem.cc";
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] ${message}`);
+}
+
+// Receiver: Listen for messages and verify mixed content handling
+async function test_mix_receive() {
+    // Connect to NATS
+    const { connect } = require('nats');
+    const nc = await connect({ servers: [NATS_URL] });
+    
+    // Subscribe to the subject
+    const sub = nc.subscribe(SUBJECT);
+    
+    for await (const msg of sub) {
+        log_trace(`Received message on ${msg.subject}`);
+        
+        // Use NATSBridge.smartreceive to handle the data
+        const result = await smartreceive(
+            msg,
+            {
+                maxRetries: 5,
+                baseDelay: 100,
+                maxDelay: 5000
+            }
+        );
+        
+        log_trace(`Received ${result.payloads.length} payloads`);
+        
+        // Result is an envelope dictionary with payloads field
+        // Access payloads with result.payloads
+        for (const { dataname, data, type } of result.payloads) {
+            log_trace(`\n=== Payload: ${dataname} (type: ${type}) ===`);
+            
+            // Handle different data types
+            if (type === "text") {
+                // Text data - should be a String
+                if (typeof data === 'string') {
+                    log_trace(`  Type: String`);
+                    log_trace(`  Length: ${data.length} characters`);
+                    
+                    // Display first 200 characters
+                    if (data.length > 200) {
+                        log_trace(`  First 200 chars: ${data.substring(0, 200)}...`);
+                    } else {
+                        log_trace(`  Content: ${data}`);
+                    }
+                    
+                    // Save to file
+                    const fs = require('fs');
+                    const output_path = `./received_${dataname}.txt`;
+                    fs.writeFileSync(output_path, data);
+                    log_trace(`  Saved to: ${output_path}`);
+                } else {
+                    log_trace(`  ERROR: Expected String, got ${typeof data}`);
+                }
+                
+            } else if (type === "dictionary") {
+                // Dictionary data - should be an object
+                if (typeof data === 'object' && data !== null && !Array.isArray(data)) {
+                    log_trace(`  Type: Object`);
+                    log_trace(`  Keys: ${Object.keys(data).join(', ')}`);
+                    
+                    // Display nested content
+                    for (const [key, value] of Object.entries(data)) {
+                        log_trace(`  ${key} => ${value}`);
+                    }
+                    
+                    // Save to JSON file
+                    const fs = require('fs');
+                    const output_path = `./received_${dataname}.json`;
+                    const json_str = JSON.stringify(data, null, 2);
+                    fs.writeFileSync(output_path, json_str);
+                    log_trace(`  Saved to: ${output_path}`);
+                } else {
+                    log_trace(`  ERROR: Expected Object, got ${typeof data}`);
+                }
+                
+            } else if (type === "table") {
+                // Table data - should be an array of objects (requires apache-arrow)
+                log_trace(`  Type: Array (requires apache-arrow for full deserialization)`);
+                if (Array.isArray(data)) {
+                    log_trace(`  Length: ${data.length} items`);
+                    log_trace(`  First item: ${JSON.stringify(data[0])}`);
+                } else {
+                    log_trace(`  ERROR: Expected Array, got ${typeof data}`);
+                }
+                
+            } else if (type === "image" || type === "audio" || type === "video" || type === "binary") {
+                // Binary data - should be Uint8Array
+                if (data instanceof Uint8Array || Array.isArray(data)) {
+                    log_trace(`  Type: Uint8Array (binary)`);
+                    log_trace(`  Size: ${data.length} bytes`);
+                    
+                    // Save to file
+                    const fs = require('fs');
+                    const output_path = `./received_${dataname}.bin`;
+                    fs.writeFileSync(output_path, Buffer.from(data));
+                    log_trace(`  Saved to: ${output_path}`);
+                } else {
+                    log_trace(`  ERROR: Expected Uint8Array, got ${typeof data}`);
+                }
+                
+            } else {
+                log_trace(`  ERROR: Unknown data type '${type}'`);
+            }
+        }
+        
+        // Summary
+        console.log("\n=== Verification Summary ===");
+        const text_count = result.payloads.filter(x => x.type === "text").length;
+        const dict_count = result.payloads.filter(x => x.type === "dictionary").length;
+        const table_count = result.payloads.filter(x => x.type === "table").length;
+        const image_count = result.payloads.filter(x => x.type === "image").length;
+        const audio_count = result.payloads.filter(x => x.type === "audio").length;
+        const video_count = result.payloads.filter(x => x.type === "video").length;
+        const binary_count = result.payloads.filter(x => x.type === "binary").length;
+        
+        log_trace(`Text payloads: ${text_count}`);
+        log_trace(`Dictionary payloads: ${dict_count}`);
+        log_trace(`Table payloads: ${table_count}`);
+        log_trace(`Image payloads: ${image_count}`);
+        log_trace(`Audio payloads: ${audio_count}`);
+        log_trace(`Video payloads: ${video_count}`);
+        log_trace(`Binary payloads: ${binary_count}`);
+        
+        // Print transport type info for each payload if available
+        console.log("\n=== Payload Details ===");
+        for (const { dataname, data, type } of result.payloads) {
+            if (["image", "audio", "video", "binary"].includes(type)) {
+                log_trace(`${dataname}: ${data.length} bytes (binary)`);
+            } else if (type === "table") {
+                log_trace(`${dataname}: ${data.length} items (Array)`);
+            } else if (type === "dictionary") {
+                log_trace(`${dataname}: ${JSON.stringify(data).length} bytes (Object)`);
+            } else if (type === "text") {
+                log_trace(`${dataname}: ${data.length} characters (String)`);
+            }
+        }
+    }
+    
+    // Keep listening for 2 minutes
+    setTimeout(() => {
+        nc.close();
+        process.exit(0);
+    }, 120000);
+}
+
+// Run the test
+console.log("Starting mixed-content transport test...");
+console.log("Note: This receiver will wait for messages from the sender.");
+console.log("Run test_js_to_js_mix_sender.js first to send test data.");
+
+// Run receiver
+console.log("\ntesting smartreceive for mixed content");
+test_mix_receive();
+
+console.log("\nTest completed.");

test/test_js_table_receiver.js

@@ -0,0 +1,87 @@
+#!/usr/bin/env node
+// Test script for Table transport testing
+// Tests receiving 1 large and 1 small Tables via direct and link transport
+// Uses NATSBridge.js smartreceive with "table" type
+//
+// Note: This test requires the apache-arrow library to deserialize table data.
+// The JavaScript implementation uses apache-arrow for Arrow IPC deserialization.
+
+const { smartreceive, log_trace } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_table_test";
+const NATS_URL = "nats.yiem.cc";
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] ${message}`);
+}
+
+// Receiver: Listen for messages and verify Table handling
+async function test_table_receive() {
+    // Connect to NATS
+    const { connect } = require('nats');
+    const nc = await connect({ servers: [NATS_URL] });
+    
+    // Subscribe to the subject
+    const sub = nc.subscribe(SUBJECT);
+    
+    for await (const msg of sub) {
+        log_trace(`Received message on ${msg.subject}`);
+        
+        // Use NATSBridge.smartreceive to handle the data
+        const result = await smartreceive(
+            msg,
+            {
+                maxRetries: 5,
+                baseDelay: 100,
+                maxDelay: 5000
+            }
+        );
+        
+        // Result is an envelope dictionary with payloads field
+        // Access payloads with result.payloads
+        for (const { dataname, data, type } of result.payloads) {
+            if (Array.isArray(data)) {
+                log_trace(`Received Table '${dataname}' of type ${type}`);
+                
+                // Display table contents
+                console.log(`  Dimensions: ${data.length} rows x ${data.length > 0 ? Object.keys(data[0]).length : 0} columns`);
+                console.log(`  Columns: ${data.length > 0 ? Object.keys(data[0]).join(', ') : ''}`);
+                
+                // Display first few rows
+                console.log(`  First 5 rows:`);
+                for (let i = 0; i < Math.min(5, data.length); i++) {
+                    console.log(`    Row ${i}: ${JSON.stringify(data[i])}`);
+                }
+                
+                // Save to JSON file
+                const fs = require('fs');
+                const output_path = `./received_${dataname}.json`;
+                const json_str = JSON.stringify(data, null, 2);
+                fs.writeFileSync(output_path, json_str);
+                log_trace(`Saved Table to ${output_path}`);
+            } else {
+                log_trace(`Received unexpected data type for '${dataname}': ${typeof data}`);
+            }
+        }
+    }
+    
+    // Keep listening for 10 seconds
+    setTimeout(() => {
+        nc.close();
+        process.exit(0);
+    }, 120000);
+}
+
+// Run the test
+console.log("Starting Table transport test...");
+console.log("Note: This receiver will wait for messages from the sender.");
+console.log("Run test_js_to_js_table_sender.js first to send test data.");
+
+// Run receiver
+console.log("testing smartreceive");
+test_table_receive();
+
+console.log("Test completed.");

test/test_js_table_sender.js

@@ -0,0 +1,165 @@
+#!/usr/bin/env node
+// Test script for Table transport testing
+// Tests sending 1 large and 1 small Tables via direct and link transport
+// Uses NATSBridge.js smartsend with "table" type
+//
+// Note: This test requires the apache-arrow library to serialize/deserialize table data.
+// The JavaScript implementation uses apache-arrow for Arrow IPC serialization.
+
+const { smartsend, uuid4, log_trace } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_table_test";
+const NATS_URL = "nats.yiem.cc";
+const FILESERVER_URL = "http://192.168.88.104:8080";
+
+// Create correlation ID for tracing
+const correlation_id = uuid4();
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] [Correlation: ${correlation_id}] ${message}`);
+}
+
+// File upload handler for plik server
+async function plik_upload_handler(fileserver_url, dataname, data, correlation_id) {
+    log_trace(correlation_id, `Uploading ${dataname} to fileserver: ${fileserver_url}`);
+    
+    // Step 1: Get upload ID and token
+    const url_getUploadID = `${fileserver_url}/upload`;
+    const headers = {
+        "Content-Type": "application/json"
+    };
+    const body = JSON.stringify({ OneShot: true });
+    
+    let response = await fetch(url_getUploadID, {
+        method: "POST",
+        headers: headers,
+        body: body
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to get upload ID: ${response.status} ${response.statusText}`);
+    }
+    
+    const responseJson = await response.json();
+    const uploadid = responseJson.id;
+    const uploadtoken = responseJson.uploadToken;
+    
+    // Step 2: Upload file data
+    const url_upload = `${fileserver_url}/file/${uploadid}`;
+    
+    // Create multipart form data
+    const formData = new FormData();
+    const blob = new Blob([data], { type: "application/octet-stream" });
+    formData.append("file", blob, dataname);
+    
+    response = await fetch(url_upload, {
+        method: "POST",
+        headers: {
+            "X-UploadToken": uploadtoken
+        },
+        body: formData
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to upload file: ${response.status} ${response.statusText}`);
+    }
+    
+    const fileResponseJson = await response.json();
+    const fileid = fileResponseJson.id;
+    
+    // Build the download URL
+    const url = `${fileserver_url}/file/${uploadid}/${fileid}/${encodeURIComponent(dataname)}`;
+    
+    log_trace(correlation_id, `Uploaded to URL: ${url}`);
+    
+    return {
+        status: response.status,
+        uploadid: uploadid,
+        fileid: fileid,
+        url: url
+    };
+}
+
+// Sender: Send Tables via smartsend
+async function test_table_send() {
+    // Note: This test requires apache-arrow library to create Arrow IPC data.
+    // For now, we'll use a simple array of objects as table data.
+    // In production, you would use the apache-arrow library to create Arrow IPC data.
+    
+    // Create a small Table (will use direct transport)
+    const small_table = [
+        { id: 1, name: "Alice", score: 95 },
+        { id: 2, name: "Bob", score: 88 },
+        { id: 3, name: "Charlie", score: 92 }
+    ];
+    
+    // Create a large Table (will use link transport if > 1MB)
+    // Generate a larger dataset (~2MB to ensure link transport)
+    const large_table = [];
+    for (let i = 0; i < 50000; i++) {
+        large_table.push({
+            id: i,
+            message: `msg_${i}`,
+            sender: `sender_${i}`,
+            timestamp: new Date().toISOString(),
+            priority: Math.floor(Math.random() * 3) + 1
+        });
+    }
+    
+    // Test data 1: small Table
+    const data1 = { dataname: "small_table", data: small_table, type: "table" };
+    
+    // Test data 2: large Table
+    const data2 = { dataname: "large_table", data: large_table, type: "table" };
+    
+    // Use smartsend with table type
+    // For small Table: will use direct transport (Arrow IPC encoded)
+    // For large Table: will use link transport (uploaded to fileserver)
+    const { env, env_json_str } = await smartsend(
+        SUBJECT,
+        [data1, data2],
+        {
+            natsUrl: NATS_URL,
+            fileserverUrl: FILESERVER_URL,
+            fileserverUploadHandler: plik_upload_handler,
+            sizeThreshold: 1_000_000,
+            correlationId: correlation_id,
+            msgPurpose: "chat",
+            senderName: "table_sender",
+            receiverName: "",
+            receiverId: "",
+            replyTo: "",
+            replyToMsgId: "",
+            isPublish: true  // Publish the message to NATS
+        }
+    );
+    
+    log_trace(`Sent message with ${env.payloads.length} payloads`);
+    
+    // Log transport type for each payload
+    for (let i = 0; i < env.payloads.length; i++) {
+        const payload = env.payloads[i];
+        log_trace(`Payload ${i + 1} ('${payload.dataname}'):`);
+        log_trace(`  Transport: ${payload.transport}`);
+        log_trace(`  Type: ${payload.type}`);
+        log_trace(`  Size: ${payload.size} bytes`);
+        log_trace(`  Encoding: ${payload.encoding}`);
+        
+        if (payload.transport === "link") {
+            log_trace(`  URL: ${payload.data}`);
+        }
+    }
+}
+
+// Run the test
+console.log("Starting Table transport test...");
+console.log(`Correlation ID: ${correlation_id}`);
+
+// Run sender
+console.log("start smartsend for tables");
+test_table_send();
+
+console.log("Test completed.");

test/test_js_text_receiver.js

@@ -0,0 +1,81 @@
+#!/usr/bin/env node
+// Test script for text transport testing
+// Tests receiving 1 large and 1 small text from JavaScript serviceA to JavaScript serviceB
+// Uses NATSBridge.js smartreceive with "text" type
+
+const { smartreceive, log_trace } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_text_test";
+const NATS_URL = "nats.yiem.cc";
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] ${message}`);
+}
+
+// Receiver: Listen for messages and verify text handling
+async function test_text_receive() {
+    // Connect to NATS
+    const { connect } = require('nats');
+    const nc = await connect({ servers: [NATS_URL] });
+    
+    // Subscribe to the subject
+    const sub = nc.subscribe(SUBJECT);
+    
+    for await (const msg of sub) {
+        log_trace(`Received message on ${msg.subject}`);
+        
+        // Use NATSBridge.smartreceive to handle the data
+        const result = await smartreceive(
+            msg,
+            {
+                maxRetries: 5,
+                baseDelay: 100,
+                maxDelay: 5000
+            }
+        );
+        
+        // Result is an envelope dictionary with payloads field
+        // Access payloads with result.payloads
+        for (const { dataname, data, type } of result.payloads) {
+            if (typeof data === 'string') {
+                log_trace(`Received text '${dataname}' of type ${type}`);
+                log_trace(`  Length: ${data.length} characters`);
+                
+                // Display first 100 characters
+                if (data.length > 100) {
+                    log_trace(`  First 100 characters: ${data.substring(0, 100)}...`);
+                } else {
+                    log_trace(`  Content: ${data}`);
+                }
+                
+                // Save to file
+                const fs = require('fs');
+                const output_path = `./received_${dataname}.txt`;
+                fs.writeFileSync(output_path, data);
+                log_trace(`Saved text to ${output_path}`);
+            } else {
+                log_trace(`Received unexpected data type for '${dataname}': ${typeof data}`);
+            }
+        }
+    }
+    
+    // Keep listening for 10 seconds
+    setTimeout(() => {
+        nc.close();
+        process.exit(0);
+    }, 120000);
+}
+
+// Run the test
+console.log("Starting text transport test...");
+console.log("Note: This receiver will wait for messages from the sender.");
+console.log("Run test_js_to_js_text_sender.js first to send test data.");
+
+// Run receiver
+console.log("testing smartreceive for text");
+test_text_receive();
+
+console.log("Test completed.");

test/test_js_text_sender.js

@@ -0,0 +1,141 @@
+#!/usr/bin/env node
+// Test script for text transport testing
+// Tests sending 1 large and 1 small text from JavaScript serviceA to JavaScript serviceB
+// Uses NATSBridge.js smartsend with "text" type
+
+const { smartsend, uuid4, log_trace } = require('./src/NATSBridge');
+
+// Configuration
+const SUBJECT = "/NATSBridge_text_test";
+const NATS_URL = "nats.yiem.cc";
+const FILESERVER_URL = "http://192.168.88.104:8080";
+
+// Create correlation ID for tracing
+const correlation_id = uuid4();
+
+// Helper: Log with correlation ID
+function log_trace(message) {
+    const timestamp = new Date().toISOString();
+    console.log(`[${timestamp}] [Correlation: ${correlation_id}] ${message}`);
+}
+
+// File upload handler for plik server
+async function plik_upload_handler(fileserver_url, dataname, data, correlation_id) {
+    // Get upload ID
+    const url_getUploadID = `${fileserver_url}/upload`;
+    const headers = {
+        "Content-Type": "application/json"
+    };
+    const body = JSON.stringify({ OneShot: true });
+    
+    let response = await fetch(url_getUploadID, {
+        method: "POST",
+        headers: headers,
+        body: body
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to get upload ID: ${response.status} ${response.statusText}`);
+    }
+    
+    const responseJson = await response.json();
+    const uploadid = responseJson.id;
+    const uploadtoken = responseJson.uploadToken;
+    
+    // Upload file
+    const formData = new FormData();
+    const blob = new Blob([data], { type: "application/octet-stream" });
+    formData.append("file", blob, dataname);
+    
+    response = await fetch(`${fileserver_url}/file/${uploadid}`, {
+        method: "POST",
+        headers: {
+            "X-UploadToken": uploadtoken
+        },
+        body: formData
+    });
+    
+    if (!response.ok) {
+        throw new Error(`Failed to upload file: ${response.status} ${response.statusText}`);
+    }
+    
+    const fileResponseJson = await response.json();
+    const fileid = fileResponseJson.id;
+    
+    const url = `${fileserver_url}/file/${uploadid}/${fileid}/${encodeURIComponent(dataname)}`;
+    
+    return {
+        status: response.status,
+        uploadid: uploadid,
+        fileid: fileid,
+        url: url
+    };
+}
+
+// Sender: Send text via smartsend
+async function test_text_send() {
+    // Create a small text (will use direct transport)
+    const small_text = "Hello, this is a small text message. Testing direct transport via NATS.";
+    
+    // Create a large text (will use link transport if > 1MB)
+    // Generate a larger text (~2MB to ensure link transport)
+    const large_text_lines = [];
+    for (let i = 0; i < 50000; i++) {
+        large_text_lines.push(`Line ${i}: This is a sample text line with some content to pad the size. `);
+    }
+    const large_text = large_text_lines.join("");
+    
+    // Test data 1: small text
+    const data1 = { dataname: "small_text", data: small_text, type: "text" };
+    
+    // Test data 2: large text
+    const data2 = { dataname: "large_text", data: large_text, type: "text" };
+    
+    // Use smartsend with text type
+    // For small text: will use direct transport (Base64 encoded UTF-8)
+    // For large text: will use link transport (uploaded to fileserver)
+    const { env, env_json_str } = await smartsend(
+        SUBJECT,
+        [data1, data2],
+        {
+            natsUrl: NATS_URL,
+            fileserverUrl: FILESERVER_URL,
+            fileserverUploadHandler: plik_upload_handler,
+            sizeThreshold: 1_000_000,
+            correlationId: correlation_id,
+            msgPurpose: "chat",
+            senderName: "text_sender",
+            receiverName: "",
+            receiverId: "",
+            replyTo: "",
+            replyToMsgId: "",
+            isPublish: true  // Publish the message to NATS
+        }
+    );
+    
+    log_trace(`Sent message with ${env.payloads.length} payloads`);
+    
+    // Log transport type for each payload
+    for (let i = 0; i < env.payloads.length; i++) {
+        const payload = env.payloads[i];
+        log_trace(`Payload ${i + 1} ('${payload.dataname}'):`);
+        log_trace(`  Transport: ${payload.transport}`);
+        log_trace(`  Type: ${payload.type}`);
+        log_trace(`  Size: ${payload.size} bytes`);
+        log_trace(`  Encoding: ${payload.encoding}`);
+        
+        if (payload.transport === "link") {
+            log_trace(`  URL: ${payload.data}`);
+        }
+    }
+}
+
+// Run the test
+console.log("Starting text transport test...");
+console.log(`Correlation ID: ${correlation_id}`);
+
+// Run sender
+console.log("start smartsend for text");
+test_text_send();
+
+console.log("Test completed.");

test/test_julia_dict_receiver.jl

@@ -0,0 +1,82 @@
+#!/usr/bin/env julia
+# Test script for Dictionary transport testing
+# Tests receiving 1 large and 1 small Dictionaries via direct and link transport
+# Uses NATSBridge.jl smartreceive with "dictionary" type
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_dict_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                        test dictionary transfer                                  #
+# ------------------------------------------------------------------------------------------------ #
+
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] $message")
+end
+
+
+# Receiver: Listen for messages and verify Dictionary handling
+function test_dict_receive()
+    conn = NATS.connect(NATS_URL)
+    NATS.subscribe(conn, SUBJECT) do msg
+        log_trace("Received message on $(msg.subject)")
+        
+        # Use NATSBridge.smartreceive to handle the data
+        # API: smartreceive(msg, download_handler; max_retries, base_delay, max_delay)
+        result = NATSBridge.smartreceive(
+            msg;
+            max_retries = 5,
+            base_delay = 100,
+            max_delay = 5000
+        )
+        
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
+        for (dataname, data, data_type) in result["payloads"]
+            if isa(data, JSON.Object{String, Any})
+                log_trace("Received Dictionary '$dataname' of type $data_type")
+                
+                # Display dictionary contents
+                println("  Contents:")
+                for (key, value) in data
+                    println("    $key => $value")
+                end
+                
+                # Save to JSON file
+                output_path = "./received_$dataname.json"
+                json_str = JSON.json(data, 2)
+                write(output_path, json_str)
+                log_trace("Saved Dictionary to $output_path")
+            else
+                log_trace("Received unexpected data type for '$dataname': $(typeof(data))")
+            end
+        end
+    end
+    
+    # Keep listening for 10 seconds
+    sleep(120)  
+    NATS.drain(conn)
+end
+
+
+# Run the test
+println("Starting Dictionary transport test...")
+println("Note: This receiver will wait for messages from the sender.")
+println("Run test_julia_to_julia_dict_sender.jl first to send test data.")
+
+# Run receiver
+println("testing smartreceive")
+test_dict_receive()
+
+println("Test completed.")

test/test_julia_dict_sender.jl

@@ -0,0 +1,137 @@
+#!/usr/bin/env julia
+# Test script for Dictionary transport testing
+# Tests sending 1 large and 1 small Dictionaries via direct and link transport
+# Uses NATSBridge.jl smartsend with "dictionary" type
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_dict_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+# Create correlation ID for tracing
+correlation_id = string(uuid4())
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                        test dictionary transfer                                  #
+# ------------------------------------------------------------------------------------------------ #
+
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] [Correlation: $correlation_id] $message")
+end
+
+
+# File upload handler for plik server
+function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
+    # Get upload ID
+    url_getUploadID = "$fileserver_url/upload"
+    headers = ["Content-Type" => "application/json"]
+    body = """{ "OneShot" : true }"""
+    httpResponse = HTTP.request("POST", url_getUploadID, headers, body; body_is_form=false)
+    responseJson = JSON.parse(String(httpResponse.body))
+    uploadid = responseJson["id"]
+    uploadtoken = responseJson["uploadToken"]
+    
+    # Upload file
+    file_multipart = HTTP.Multipart(dataname, IOBuffer(data), "application/octet-stream")
+    url_upload = "$fileserver_url/file/$uploadid"
+    headers = ["X-UploadToken" => uploadtoken]
+    
+    form = HTTP.Form(Dict("file" => file_multipart))
+    httpResponse = HTTP.post(url_upload, headers, form)
+    responseJson = JSON.parse(String(httpResponse.body))
+    
+    fileid = responseJson["id"]
+    url = "$fileserver_url/file/$uploadid/$fileid/$dataname"
+    
+    return Dict("status" => httpResponse.status, "uploadid" => uploadid, "fileid" => fileid, "url" => url)
+end
+
+
+# Sender: Send Dictionaries via smartsend
+function test_dict_send()
+    # Create a small Dictionary (will use direct transport)
+    small_dict = Dict(
+        "name" => "Alice",
+        "age" => 30,
+        "scores" => [95, 88, 92],
+        "metadata" => Dict(
+            "height" => 155,
+            "weight" => 55
+        )
+    )
+    
+    # Create a large Dictionary (will use link transport if > 1MB)
+    # Generate a larger dataset (~2MB to ensure link transport)
+    large_dict = Dict(
+        "ids" => collect(1:50000),
+        "names" => ["User_$i" for i in 1:50000],
+        "scores" => rand(1:100, 50000),
+        "categories" => ["Category_$(rand(1:10))" for i in 1:50000],
+        "metadata" => Dict(
+            "source" => "test_generator",
+            "timestamp" => string(Dates.now())
+        )
+    )
+    
+    # Test data 1: small Dictionary
+    data1 = ("small_dict", small_dict, "dictionary")
+    
+    # Test data 2: large Dictionary
+    data2 = ("large_dict", large_dict, "dictionary")
+    
+    # Use smartsend with dictionary type
+    # For small Dictionary: will use direct transport (JSON encoded)
+    # For large Dictionary: will use link transport (uploaded to fileserver)
+    env, env_json_str = NATSBridge.smartsend(
+        SUBJECT,
+        [data1, data2];  # List of (dataname, data, type) tuples
+        broker_url = NATS_URL,
+        fileserver_url = FILESERVER_URL,
+        fileserver_upload_handler = plik_upload_handler,
+        size_threshold = 1_000_000,  # 1MB threshold
+        correlation_id = correlation_id,
+        msg_purpose = "chat",
+        sender_name = "dict_sender",
+        receiver_name = "",
+        receiver_id = "",
+        reply_to = "",
+        reply_to_msg_id = "",
+        is_publish = true  # Publish the message to NATS
+    )
+    
+    log_trace("Sent message with $(length(env.payloads)) payloads")
+    
+    # Log transport type for each payload
+    for (i, payload) in enumerate(env.payloads)
+        log_trace("Payload $i ('$payload.dataname'):")
+        log_trace("  Transport: $(payload.transport)")
+        log_trace("  Type: $(payload.payload_type)")
+        log_trace("  Size: $(payload.size) bytes")
+        log_trace("  Encoding: $(payload.encoding)")
+        
+        if payload.transport == "link"
+            log_trace("  URL: $(payload.data)")
+        end
+    end
+end
+
+
+# Run the test
+println("Starting Dictionary transport test...")
+println("Correlation ID: $correlation_id")
+
+# Run sender
+println("start smartsend for dictionaries")
+test_dict_send()
+
+println("Test completed.")

test/test_julia_file_receiver.jl

@@ -0,0 +1,84 @@
+#!/usr/bin/env julia
+# Test script for large payload testing using binary transport
+# Tests sending a large file (> 1MB) via smartsend with binary type
+# Updated to match NATSBridge.jl API
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP
+
+
+# workdir = 
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                        test file transfer                                        #
+# ------------------------------------------------------------------------------------------------ #
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] $message")
+end
+
+# Receiver: Listen for messages and verify large payload handling
+function test_large_binary_receive()
+    conn = NATS.connect(NATS_URL)
+    NATS.subscribe(conn, SUBJECT) do msg
+        log_trace("Received message on $(msg.subject)")
+        
+        # Use NATSBridge.smartreceive to handle the data
+        # API: smartreceive(msg, download_handler; max_retries, base_delay, max_delay)
+        result = NATSBridge.smartreceive(
+            msg;
+            max_retries = 5,
+            base_delay = 100,
+            max_delay = 5000
+        )
+        
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
+        for (dataname, data, data_type) in result["payloads"]
+            # Check transport type from the envelope
+            # For link transport, data is the URL string
+            # For direct transport, data is the actual payload bytes
+            
+            if isa(data, Vector{UInt8})
+                file_size = length(data)
+                log_trace("Received $(file_size) bytes of binary data for '$dataname' of type $data_type")
+                
+                # Save received data to a test file
+                output_path = "./new_$dataname"
+                write(output_path, data)
+                log_trace("Saved received data to $output_path")
+            else
+                log_trace("Received $(file_size) bytes of binary data for '$dataname' of type $data_type")
+            end
+        end
+    end
+    
+    # Keep listening for 10 seconds
+    sleep(120)  
+    NATS.drain(conn)
+end
+
+
+# Run the test
+println("Starting large binary payload test...")
+
+# # Run sender first
+# println("start smartsend")
+# test_large_binary_send()
+
+# Run receiver
+println("testing smartreceive")
+test_large_binary_receive()
+
+println("Test completed.")

test/test_julia_file_sender.jl

@@ -0,0 +1,123 @@
+#!/usr/bin/env julia
+# Test script for large payload testing using binary transport
+# Tests sending a large file (> 1MB) via smartsend with binary type
+# Updated to match NATSBridge.jl API
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP
+
+
+# workdir = 
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+# Create correlation ID for tracing
+correlation_id = string(uuid4())
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                        test file transfer                                        #
+# ------------------------------------------------------------------------------------------------ #
+
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] [Correlation: $correlation_id] $message")
+end
+
+# File upload handler for plik server
+function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
+    # Get upload ID
+    url_getUploadID = "$fileserver_url/upload"
+    headers = ["Content-Type" => "application/json"]
+    body = """{ "OneShot" : true }"""
+    httpResponse = HTTP.request("POST", url_getUploadID, headers, body; body_is_form=false)
+    responseJson = JSON.parse(String(httpResponse.body))
+    uploadid = responseJson["id"]
+    uploadtoken = responseJson["uploadToken"]
+    
+    # Upload file
+    file_multipart = HTTP.Multipart(dataname, IOBuffer(data), "application/octet-stream")
+    url_upload = "$fileserver_url/file/$uploadid"
+    headers = ["X-UploadToken" => uploadtoken]
+    
+    form = HTTP.Form(Dict("file" => file_multipart))
+    httpResponse = HTTP.post(url_upload, headers, form)
+    responseJson = JSON.parse(String(httpResponse.body))
+    
+    fileid = responseJson["id"]
+    url = "$fileserver_url/file/$uploadid/$fileid/$dataname"
+    
+    return Dict("status" => httpResponse.status, "uploadid" => uploadid, "fileid" => fileid, "url" => url)
+end
+
+# Sender: Send large binary file via smartsend
+function test_large_binary_send()
+    # Read the large file as binary data
+    
+    # test data 1
+    file_path1 = "./testFile_large.zip"
+    file_data1 = read(file_path1)
+    filename1 = basename(file_path1)
+    data1 = (filename1, file_data1, "binary")
+
+    # test data 2
+    file_path2 = "./testFile_small.zip"
+    file_data2 = read(file_path2)
+    filename2 = basename(file_path2)
+    data2 = (filename2, file_data2, "binary")
+    
+    
+    
+    # Use smartsend with binary type - will automatically use link transport
+    # if file size exceeds the threshold (1MB by default)
+    # API: smartsend(subject, [(dataname, data, type), ...]; keywords...)
+    env, env_json_str = NATSBridge.smartsend(
+        SUBJECT,
+        [data1, data2];  # List of (dataname, data, type) tuples
+        broker_url = NATS_URL;
+        fileserver_url = FILESERVER_URL,
+        fileserver_upload_handler = plik_upload_handler,
+        size_threshold = 1_000_000,
+        correlation_id = correlation_id,
+        msg_purpose = "chat",
+        sender_name = "sender",
+        receiver_name = "",
+        receiver_id = "",
+        reply_to = "",
+        reply_to_msg_id = "",
+        is_publish = true  # Publish the message to NATS
+    )
+    
+    log_trace("Sent message with transport: $(env.payloads[1].transport)")
+    log_trace("Envelope type: $(env.payloads[1].payload_type)")
+    
+    # Check if link transport was used
+    if env.payloads[1].transport == "link"
+        log_trace("Using link transport - file uploaded to HTTP server")
+        log_trace("URL: $(env.payloads[1].data)")
+    else
+        log_trace("Using direct transport - payload sent via NATS")
+    end
+end
+
+# Run the test
+println("Starting large binary payload test...")
+println("Correlation ID: $correlation_id")
+
+# Run sender first
+println("start smartsend")
+test_large_binary_send()
+
+# Run receiver
+# println("testing smartreceive")
+# test_large_binary_receive()
+
+println("Test completed.")

test/test_julia_julia_data_transfer.jl

@@ -1,190 +0,0 @@
-#!/usr/bin/env julia
-# Test script for large payload testing using binary transport
-# Tests sending a large file (> 1MB) via smartsend with binary type
-
-using NATS, JSON, UUIDs, Dates
-
-# Include the bridge module
-include("../src/NATSBridge.jl")
-using .NATSBridge
-
-# Configuration
-const SUBJECT = "/large_binary_test"
-const NATS_URL = "nats.yiem.cc"
-const FILESERVER_URL = "http://192.168.88.104:8080"
-
-# Create correlation ID for tracing
-correlation_id = string(uuid4())
-
-
-# ------------------------------------------------------------------------------------------------ #
-#                                        test file transfer                                        #
-# ------------------------------------------------------------------------------------------------ #
-
-# File path for large binary payload test
-const FILE_PATH = "./testFile_small.zip"
-const filename = basename(FILE_PATH)
-
-# Helper: Log with correlation ID
-function log_trace(message)
-    timestamp = Dates.now()
-    println("[$timestamp] [Correlation: $correlation_id] $message")
-end
-
-# Sender: Send large binary file via smartsend
-function test_large_binary_send()
-    conn = NATS.connect(NATS_URL)
-    # Read the large file as binary data
-    log_trace("Reading large file: $FILE_PATH")
-    file_data = read(FILE_PATH)
-    
-    file_size = length(file_data)
-    log_trace("File size: $file_size bytes")
-    
-    # Use smartsend with binary type - will automatically use link transport
-    # if file size exceeds the threshold (1MB by default)
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        file_data,
-        "binary",
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL;
-        dataname=filename
-    )
-    
-    log_trace("Sent message with transport: $(env.transport)")
-    log_trace("Envelope type: $(env.type)")
-    
-    # Check if link transport was used
-    if env.transport == "link"
-        log_trace("Using link transport - file uploaded to HTTP server")
-        log_trace("URL: $(env.url)")
-    else
-        log_trace("Using direct transport - payload sent via NATS")
-    end
-    
-    NATS.drain(conn)
-end
-
-# Receiver: Listen for messages and verify large payload handling
-function test_large_binary_receive()
-  conn = NATS.connect(NATS_URL)
-  NATS.subscribe(conn, SUBJECT) do msg
-    log_trace("Received message on $(msg.subject)")
-    
-    # Use NATSBridge.smartreceive to handle the data
-    result = NATSBridge.smartreceive(msg)
-    # Check transport type
-    if result.envelope.transport == "direct"
-        log_trace("Received direct transport")
-    else
-        # For link transport, result.data is the URL
-        log_trace("Received link transport")
-    end
-              
-    # Verify the received data matches the original
-    if result.envelope.type == "binary"
-      if isa(result.data, Vector{UInt8})
-        file_size = length(result.data)
-        log_trace("Received $(file_size) bytes of binary data")
-        
-        # Save received data to a test file
-        println("metadata ", result.envelope.metadata)
-        dataname = result.envelope.metadata["dataname"]
-        if dataname != "NA"
-          output_path = "./new_$dataname"
-          write(output_path, result.data)
-          log_trace("Saved received data to $output_path")
-        end
-        
-        # Verify file size
-        original_size = length(read(FILE_PATH))
-        if file_size == result.envelope.metadata["content_length"]
-            log_trace("SUCCESS: File size matches! Original: $(result.envelope.metadata["content_length"]) bytes")
-        else
-            log_trace("WARNING: File size mismatch! Original: $(result.envelope.metadata["content_length"]), Received: $file_size")
-        end
-      end
-    end
-  end
-
-  # Keep listening for 10 seconds
-  sleep(120)  
-  NATS.drain(conn)
-end
-
-
-# Run the test
-println("Starting large binary payload test...")
-println("Correlation ID: $correlation_id")
-println("File: $FILE_PATH")
-
-# Run sender first
-println("start smartsend")
-test_large_binary_send()
-
-# # Run receiver
-# println("testing smartreceive")
-# test_large_binary_receive()
-
-println("Test completed.")
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
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test/test_julia_mix_payloads_receiver.jl

@@ -0,0 +1,228 @@
+#!/usr/bin/env julia
+# Test script for mixed-content message testing
+# Tests receiving a mix of text, json, table, image, audio, video, and binary data
+# from Julia serviceA to Julia serviceB using NATSBridge.jl smartreceive
+#
+# This test demonstrates that any combination and any number of mixed content
+# can be sent and received correctly.
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP, Base64
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_mix_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                      test mixed content transfer                                 #
+# ------------------------------------------------------------------------------------------------ #
+
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] $message")
+end
+
+
+# Receiver: Listen for messages and verify mixed content handling
+function test_mix_receive()
+    conn = NATS.connect(NATS_URL)
+    NATS.subscribe(conn, SUBJECT) do msg
+        log_trace("Received message on $(msg.subject)")
+        
+        # Use NATSBridge.smartreceive to handle the data
+        # API: smartreceive(msg, download_handler; max_retries, base_delay, max_delay)
+        result = NATSBridge.smartreceive(
+            msg;
+            max_retries = 5,
+            base_delay = 100,
+            max_delay = 5000
+        )
+        
+        log_trace("Received $(length(result["payloads"])) payloads")
+        
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
+        for (dataname, data, data_type) in result["payloads"]
+            log_trace("\n=== Payload: $dataname (type: $data_type) ===")
+            
+            # Handle different data types
+            if data_type == "text"
+                # Text data - should be a String
+                if isa(data, String)
+                    log_trace("  Type: String")
+                    log_trace("  Length: $(length(data)) characters")
+                    
+                    # Display first 200 characters
+                    if length(data) > 200
+                        log_trace("  First 200 chars: $(data[1:200])...")
+                    else
+                        log_trace("  Content: $data")
+                    end
+                    
+                    # Save to file
+                    output_path = "./received_$dataname.txt"
+                    write(output_path, data)
+                    log_trace("  Saved to: $output_path")
+                else
+                    log_trace("  ERROR: Expected String, got $(typeof(data))")
+                end
+                
+            elseif data_type == "dictionary"
+                # Dictionary data - should be JSON object
+                if isa(data, JSON.Object{String, Any})
+                    log_trace("  Type: Dict")
+                    log_trace("  Keys: $(keys(data))")
+                    
+                    # Display nested content
+                    for (key, value) in data
+                        log_trace("  $key => $value")
+                    end
+                    
+                    # Save to JSON file
+                    output_path = "./received_$dataname.json"
+                    json_str = JSON.json(data, 2)
+                    write(output_path, json_str)
+                    log_trace("  Saved to: $output_path")
+                else
+                    log_trace("  ERROR: Expected Dict, got $(typeof(data))")
+                end
+                
+            elseif data_type == "table"
+                # Table data - should be a DataFrame
+                data = DataFrame(data)
+                if isa(data, DataFrame)
+                    log_trace("  Type: DataFrame")
+                    log_trace("  Dimensions: $(size(data, 1)) rows x $(size(data, 2)) columns")
+                    log_trace("  Columns: $(names(data))")
+                    
+                    # Display first few rows
+                    log_trace("  First 5 rows:")
+                    display(data[1:min(5, size(data, 1)), :])
+                    
+                    # Save to Arrow file
+                    output_path = "./received_$dataname.arrow"
+                    io = IOBuffer()
+                    Arrow.write(io, data)
+                    write(output_path, take!(io))
+                    log_trace("  Saved to: $output_path")
+                else
+                    log_trace("  ERROR: Expected DataFrame, got $(typeof(data))")
+                end
+                
+            elseif data_type == "image"
+                # Image data - should be Vector{UInt8}
+                if isa(data, Vector{UInt8})
+                    log_trace("  Type: Vector{UInt8} (binary)")
+                    log_trace("  Size: $(length(data)) bytes")
+                    
+                    # Save to file
+                    output_path = "./received_$dataname.bin"
+                    write(output_path, data)
+                    log_trace("  Saved to: $output_path")
+                else
+                    log_trace("  ERROR: Expected Vector{UInt8}, got $(typeof(data))")
+                end
+                
+            elseif data_type == "audio"
+                # Audio data - should be Vector{UInt8}
+                if isa(data, Vector{UInt8})
+                    log_trace("  Type: Vector{UInt8} (binary)")
+                    log_trace("  Size: $(length(data)) bytes")
+                    
+                    # Save to file
+                    output_path = "./received_$dataname.bin"
+                    write(output_path, data)
+                    log_trace("  Saved to: $output_path")
+                else
+                    log_trace("  ERROR: Expected Vector{UInt8}, got $(typeof(data))")
+                end
+                
+            elseif data_type == "video"
+                # Video data - should be Vector{UInt8}
+                if isa(data, Vector{UInt8})
+                    log_trace("  Type: Vector{UInt8} (binary)")
+                    log_trace("  Size: $(length(data)) bytes")
+                    
+                    # Save to file
+                    output_path = "./received_$dataname.bin"
+                    write(output_path, data)
+                    log_trace("  Saved to: $output_path")
+                else
+                    log_trace("  ERROR: Expected Vector{UInt8}, got $(typeof(data))")
+                end
+                
+            elseif data_type == "binary"
+                # Binary data - should be Vector{UInt8}
+                if isa(data, Vector{UInt8})
+                    log_trace("  Type: Vector{UInt8} (binary)")
+                    log_trace("  Size: $(length(data)) bytes")
+                    
+                    # Save to file
+                    output_path = "./received_$dataname.bin"
+                    write(output_path, data)
+                    log_trace("  Saved to: $output_path")
+                else
+                    log_trace("  ERROR: Expected Vector{UInt8}, got $(typeof(data))")
+                end
+                
+            else
+                log_trace("  ERROR: Unknown data type '$data_type'")
+            end
+        end
+        
+        # Summary
+        println("\n=== Verification Summary ===")
+        text_count = count(x -> x[3] == "text", result["payloads"])
+        dict_count = count(x -> x[3] == "dictionary", result["payloads"])
+        table_count = count(x -> x[3] == "table", result["payloads"])
+        image_count = count(x -> x[3] == "image", result["payloads"])
+        audio_count = count(x -> x[3] == "audio", result["payloads"])
+        video_count = count(x -> x[3] == "video", result["payloads"])
+        binary_count = count(x -> x[3] == "binary", result["payloads"])
+        
+        log_trace("Text payloads: $text_count")
+        log_trace("Dictionary payloads: $dict_count")
+        log_trace("Table payloads: $table_count")
+        log_trace("Image payloads: $image_count")
+        log_trace("Audio payloads: $audio_count")
+        log_trace("Video payloads: $video_count")
+        log_trace("Binary payloads: $binary_count")
+        
+        # Print transport type info for each payload if available
+        println("\n=== Payload Details ===")
+        for (dataname, data, data_type) in result["payloads"]
+            if data_type in ["image", "audio", "video", "binary"]
+                log_trace("$dataname: $(length(data)) bytes (binary)")
+            elseif data_type == "table"
+              data = DataFrame(data)
+                log_trace("$dataname: $(size(data, 1)) rows x $(size(data, 2)) columns (DataFrame)")
+            elseif data_type == "dictionary"
+                log_trace("$dataname: $(length(JSON.json(data))) bytes (Dict)")
+            elseif data_type == "text"
+                log_trace("$dataname: $(length(data)) characters (String)")
+            end
+        end
+    end
+    
+    # Keep listening for 2 minutes
+    sleep(120)  
+    NATS.drain(conn)
+end
+
+
+# Run the test
+println("Starting mixed-content transport test...")
+println("Note: This receiver will wait for messages from the sender.")
+println("Run test_julia_to_julia_mix_sender.jl first to send test data.")
+
+# Run receiver
+println("\ntesting smartreceive for mixed content")
+test_mix_receive()
+
+println("\nTest completed.")

test/test_julia_mix_payloads_sender.jl

@@ -0,0 +1,239 @@
+#!/usr/bin/env julia
+# Test script for mixed-content message testing
+# Tests sending a mix of text, json, table, image, audio, video, and binary data
+# from Julia serviceA to Julia serviceB using NATSBridge.jl smartsend
+# 
+# This test demonstrates that any combination and any number of mixed content
+# can be sent and received correctly.
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP, Base64
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_mix_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+# Create correlation ID for tracing
+correlation_id = string(uuid4())
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                      test mixed content transfer                                 #
+# ------------------------------------------------------------------------------------------------ #
+
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] [Correlation: $correlation_id] $message")
+end
+
+
+# File upload handler for plik server
+function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
+    # Get upload ID
+    url_getUploadID = "$fileserver_url/upload"
+    headers = ["Content-Type" => "application/json"]
+    body = """{ "OneShot" : true }"""
+    httpResponse = HTTP.request("POST", url_getUploadID, headers, body; body_is_form=false)
+    responseJson = JSON.parse(String(httpResponse.body))
+    uploadid = responseJson["id"]
+    uploadtoken = responseJson["uploadToken"]
+    
+    # Upload file
+    file_multipart = HTTP.Multipart(dataname, IOBuffer(data), "application/octet-stream")
+    url_upload = "$fileserver_url/file/$uploadid"
+    headers = ["X-UploadToken" => uploadtoken]
+    
+    form = HTTP.Form(Dict("file" => file_multipart))
+    httpResponse = HTTP.post(url_upload, headers, form)
+    responseJson = JSON.parse(String(httpResponse.body))
+    
+    fileid = responseJson["id"]
+    url = "$fileserver_url/file/$uploadid/$fileid/$dataname"
+    
+    return Dict("status" => httpResponse.status, "uploadid" => uploadid, "fileid" => fileid, "url" => url)
+end
+
+
+# Helper: Create sample data for each type
+function create_sample_data()
+    # Text data (small - direct transport)
+    text_data = "Hello! This is a test chat message. 🎉\nHow are you doing today? 😊"
+    
+    # Dictionary/JSON data (medium - could be direct or link)
+    dict_data = Dict(
+        "type" => "chat",
+        "sender" => "serviceA",
+        "receiver" => "serviceB",
+        "metadata" => Dict(
+            "timestamp" => string(Dates.now()),
+            "priority" => "high",
+            "tags" => ["urgent", "chat", "test"]
+        ),
+        "content" => Dict(
+            "text" => "This is a JSON-formatted chat message with nested structure.",
+            "format" => "markdown",
+            "mentions" => ["user1", "user2"]
+        )
+    )
+    
+    # Table data (DataFrame - small - direct transport)
+    table_data_small = DataFrame(
+        id = 1:10,
+        message = ["msg_$i" for i in 1:10],
+        sender = ["sender_$i" for i in 1:10],
+        timestamp = [string(Dates.now()) for _ in 1:10],
+        priority = rand(1:3, 10)
+    )
+    
+    # Table data (DataFrame - large - link transport)
+    # ~1.5MB of data (150,000 rows) - should trigger link transport
+    table_data_large = DataFrame(
+        id = 1:150_000,
+        message = ["msg_$i" for i in 1:150_000],
+        sender = ["sender_$i" for i in 1:150_000],
+        timestamp = [string(Dates.now()) for i in 1:150_000],
+        priority = rand(1:3, 150_000)
+    )
+    
+    # Image data (small binary - direct transport)
+    # Create a simple 10x10 pixel PNG-like data (128 bytes header + 100 pixels = 112 bytes)
+    # Using simple RGB data (10*10*3 = 300 bytes of pixel data)
+    image_width = 10
+    image_height = 10
+    image_data = UInt8[]
+    # PNG header (simplified)
+    push!(image_data, 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A)
+    # Simple RGB data (RGBRGBRGB...)
+    for i in 1:image_width*image_height
+        push!(image_data, 0xFF, 0x00, 0x00)  # Red pixel
+    end
+    
+    # Image data (large - link transport)
+    # Create a larger image (~1.5MB) to test link transport
+    large_image_width = 500
+    large_image_height = 1000
+    large_image_data = UInt8[]
+    # PNG header (simplified for 500x1000)
+    push!(large_image_data, 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A)
+    # RGB data (500*1000*3 = 1,500,000 bytes)
+    for i in 1:large_image_width*large_image_height
+        push!(large_image_data, rand(1:255), rand(1:255), rand(1:255))  # Random color pixels
+    end
+    
+    # Audio data (small binary - direct transport)
+    audio_data = UInt8[rand(1:255) for _ in 1:100]
+    
+    # Audio data (large - link transport)
+    # ~1.5MB of audio-like data
+    large_audio_data = UInt8[rand(1:255) for _ in 1:1_500_000]
+    
+    # Video data (small binary - direct transport)
+    video_data = UInt8[rand(1:255) for _ in 1:150]
+    
+    # Video data (large - link transport)
+    # ~1.5MB of video-like data
+    large_video_data = UInt8[rand(1:255) for _ in 1:1_500_000]
+    
+    # Binary data (small - direct transport)
+    binary_data = UInt8[rand(1:255) for _ in 1:200]
+    
+    # Binary data (large - link transport)
+    # ~1.5MB of binary data
+    large_binary_data = UInt8[rand(1:255) for _ in 1:1_500_000]
+    
+    return (
+        text_data,
+        dict_data,
+        table_data_small,
+        table_data_large,
+        image_data,
+        large_image_data,
+        audio_data,
+        large_audio_data,
+        video_data,
+        large_video_data,
+        binary_data,
+        large_binary_data
+    )
+end
+
+
+# Sender: Send mixed content via smartsend
+function test_mix_send()
+    # Create sample data
+    (text_data, dict_data, table_data_small, table_data_large, image_data, large_image_data, audio_data, large_audio_data, video_data, large_video_data, binary_data, large_binary_data) = create_sample_data()
+    
+    # Create payloads list - mixed content with both small and large data
+    # Small data uses direct transport, large data uses link transport
+    payloads = [
+        # Small data (direct transport) - text, dictionary, small table
+        ("chat_text", text_data, "text"),
+        ("chat_json", dict_data, "dictionary"),
+        ("chat_table_small", table_data_small, "table"),
+        
+        # Large data (link transport) - large table, large image, large audio, large video, large binary
+        ("chat_table_large", table_data_large, "table"),
+        ("user_image_large", large_image_data, "image"),
+        ("audio_clip_large", large_audio_data, "audio"),
+        ("video_clip_large", large_video_data, "video"),
+        ("binary_file_large", large_binary_data, "binary")
+    ]
+    
+    # Use smartsend with mixed content
+    env, env_json_str = NATSBridge.smartsend(
+        SUBJECT,
+        payloads;  # List of (dataname, data, type) tuples
+        broker_url = NATS_URL,
+        fileserver_url = FILESERVER_URL,
+        fileserver_upload_handler = plik_upload_handler,
+        size_threshold = 1_000_000,  # 1MB threshold
+        correlation_id = correlation_id,
+        msg_purpose = "chat",
+        sender_name = "mix_sender",
+        receiver_name = "",
+        receiver_id = "",
+        reply_to = "",
+        reply_to_msg_id = "",
+        is_publish = true  # Publish the message to NATS
+    )
+    
+    log_trace("Sent message with $(length(env.payloads)) payloads")
+    
+    # Log transport type for each payload
+    for (i, payload) in enumerate(env.payloads)
+        log_trace("Payload $i ('$payload.dataname'):")
+        log_trace("  Transport: $(payload.transport)")
+        log_trace("  Type: $(payload.payload_type)")
+        log_trace("  Size: $(payload.size) bytes")
+        log_trace("  Encoding: $(payload.encoding)")
+        
+        if payload.transport == "link"
+            log_trace("  URL: $(payload.data)")
+        end
+    end
+    
+    # Summary
+    println("\n--- Transport Summary ---")
+    direct_count = count(p -> p.transport == "direct", env.payloads)
+    link_count = count(p -> p.transport == "link", env.payloads)
+    log_trace("Direct transport: $direct_count payloads")
+    log_trace("Link transport: $link_count payloads")
+end
+
+
+# Run the test
+println("Starting mixed-content transport test...")
+println("Correlation ID: $correlation_id")
+
+# Run sender
+println("start smartsend for mixed content")
+test_mix_send()
+
+println("\nTest completed.")
+println("Note: Run test_julia_to_julia_mix_receiver.jl to receive the messages.")

test/test_julia_table_receiver.jl

@@ -0,0 +1,84 @@
+#!/usr/bin/env julia
+# Test script for DataFrame table transport testing
+# Tests receiving 1 large and 1 small DataFrames via direct and link transport
+# Uses NATSBridge.jl smartreceive with "table" type
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_table_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                        test table transfer                                       #
+# ------------------------------------------------------------------------------------------------ #
+
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] $message")
+end
+
+
+# Receiver: Listen for messages and verify DataFrame table handling
+function test_table_receive()
+    conn = NATS.connect(NATS_URL)
+    NATS.subscribe(conn, SUBJECT) do msg
+        log_trace("Received message on $(msg.subject)")
+        
+        # Use NATSBridge.smartreceive to handle the data
+        # API: smartreceive(msg, download_handler; max_retries, base_delay, max_delay)
+        result = NATSBridge.smartreceive(
+            msg;
+            max_retries = 5,
+            base_delay = 100,
+            max_delay = 5000
+        )
+        
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
+        for (dataname, data, data_type) in result["payloads"]
+          data = DataFrame(data)
+            if isa(data, DataFrame)
+                log_trace("Received DataFrame '$dataname' of type $data_type")
+                log_trace("  Dimensions: $(size(data, 1)) rows x $(size(data, 2)) columns")
+                log_trace("  Column names: $(names(data))")
+                
+                # Display first few rows
+                println("  First 5 rows:")
+                display(data[1:min(5, size(data, 1)), :])
+                
+                # Save to file
+                output_path = "./received_$dataname.arrow"
+                io = IOBuffer()
+                Arrow.write(io, data)
+                write(output_path, take!(io))
+                log_trace("Saved DataFrame to $output_path")
+            else
+                log_trace("Received unexpected data type for '$dataname': $(typeof(data))")
+            end
+        end
+    end
+    
+    # Keep listening for 10 seconds
+    sleep(120)  
+    NATS.drain(conn)
+end
+
+
+# Run the test
+println("Starting DataFrame table transport test...")
+println("Note: This receiver will wait for messages from the sender.")
+println("Run test_julia_to_julia_table_sender.jl first to send test data.")
+
+# Run receiver
+println("testing smartreceive")
+test_table_receive()
+
+println("Test completed.")

test/test_julia_table_sender.jl

@@ -0,0 +1,135 @@
+#!/usr/bin/env julia
+# Test script for DataFrame table transport testing
+# Tests sending 1 large and 1 small DataFrames via direct and link transport
+# Uses NATSBridge.jl smartsend with "table" type
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_table_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+# Create correlation ID for tracing
+correlation_id = string(uuid4())
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                        test table transfer                                       #
+# ------------------------------------------------------------------------------------------------ #
+
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] [Correlation: $correlation_id] $message")
+end
+
+
+# File upload handler for plik server
+function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
+    # Get upload ID
+    url_getUploadID = "$fileserver_url/upload"
+    headers = ["Content-Type" => "application/json"]
+    body = """{ "OneShot" : true }"""
+    httpResponse = HTTP.request("POST", url_getUploadID, headers, body; body_is_form=false)
+    responseJson = JSON.parse(String(httpResponse.body))
+    uploadid = responseJson["id"]
+    uploadtoken = responseJson["uploadToken"]
+    
+    # Upload file
+    file_multipart = HTTP.Multipart(dataname, IOBuffer(data), "application/octet-stream")
+    url_upload = "$fileserver_url/file/$uploadid"
+    headers = ["X-UploadToken" => uploadtoken]
+    
+    form = HTTP.Form(Dict("file" => file_multipart))
+    httpResponse = HTTP.post(url_upload, headers, form)
+    responseJson = JSON.parse(String(httpResponse.body))
+    
+    fileid = responseJson["id"]
+    url = "$fileserver_url/file/$uploadid/$fileid/$dataname"
+    
+    return Dict("status" => httpResponse.status, "uploadid" => uploadid, "fileid" => fileid, "url" => url)
+end
+
+
+# Sender: Send DataFrame tables via smartsend
+function test_table_send()
+    # Create a small DataFrame (will use direct transport)
+    small_df = DataFrame(
+        id = 1:10,
+        name = ["Alice", "Bob", "Charlie", "Diana", "Eve", "Frank", "Grace", "Henry", "Ivy", "Jack"],
+        score = [95, 88, 92, 85, 90, 78, 95, 88, 92, 85],
+        category = ["A", "B", "A", "B", "A", "B", "A", "B", "A", "B"]
+    )
+    
+    # Create a large DataFrame (will use link transport if > 1MB)
+    # Generate a larger dataset (~2MB to ensure link transport)
+    large_ids = 1:50000
+    large_names = ["User_$i" for i in 1:50000]
+    large_scores = rand(1:100, 50000)
+    large_categories = ["Category_$(rand(1:10))" for i in 1:50000]
+    
+    large_df = DataFrame(
+        id = large_ids,
+        name = large_names,
+        score = large_scores,
+        category = large_categories
+    )
+    
+    # Test data 1: small DataFrame
+    data1 = ("small_table", small_df, "table")
+    
+    # Test data 2: large DataFrame
+    data2 = ("large_table", large_df, "table")
+    
+    # Use smartsend with table type
+    # For small DataFrame: will use direct transport (Base64 encoded Arrow IPC)
+    # For large DataFrame: will use link transport (uploaded to fileserver)
+    env, env_json_str = NATSBridge.smartsend(
+        SUBJECT,
+        [data1, data2];  # List of (dataname, data, type) tuples
+        broker_url = NATS_URL,
+        fileserver_url = FILESERVER_URL,
+        fileserver_upload_handler = plik_upload_handler,
+        size_threshold = 1_000_000,  # 1MB threshold
+        correlation_id = correlation_id,
+        msg_purpose = "chat",
+        sender_name = "table_sender",
+        receiver_name = "",
+        receiver_id = "",
+        reply_to = "",
+        reply_to_msg_id = "",
+        is_publish = true  # Publish the message to NATS
+    )
+    
+    log_trace("Sent message with $(length(env.payloads)) payloads")
+    
+    # Log transport type for each payload
+    for (i, payload) in enumerate(env.payloads)
+        log_trace("Payload $i ('$payload.dataname'):")
+        log_trace("  Transport: $(payload.transport)")
+        log_trace("  Type: $(payload.payload_type)")
+        log_trace("  Size: $(payload.size) bytes")
+        log_trace("  Encoding: $(payload.encoding)")
+        
+        if payload.transport == "link"
+            log_trace("  URL: $(payload.data)")
+        end
+    end
+end
+
+
+# Run the test
+println("Starting DataFrame table transport test...")
+println("Correlation ID: $correlation_id")
+
+# Run sender
+println("start smartsend for tables")
+test_table_send()
+
+println("Test completed.")

test/test_julia_text_receiver.jl

@@ -0,0 +1,83 @@
+#!/usr/bin/env julia
+# Test script for text transport testing
+# Tests receiving 1 large and 1 small text from Julia serviceA to Julia serviceB
+# Uses NATSBridge.jl smartreceive with "text" type
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_text_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                        test text transfer                                        #
+# ------------------------------------------------------------------------------------------------ #
+
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] $message")
+end
+
+
+# Receiver: Listen for messages and verify text handling
+function test_text_receive()
+    conn = NATS.connect(NATS_URL)
+    NATS.subscribe(conn, SUBJECT) do msg
+        log_trace("Received message on $(msg.subject)")
+        
+        # Use NATSBridge.smartreceive to handle the data
+        # API: smartreceive(msg, download_handler; max_retries, base_delay, max_delay)
+        result = NATSBridge.smartreceive(
+            msg;
+            max_retries = 5,
+            base_delay = 100,
+            max_delay = 5000
+        )
+        
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
+        for (dataname, data, data_type) in result["payloads"]
+            if isa(data, String)
+                log_trace("Received text '$dataname' of type $data_type")
+                log_trace("  Length: $(length(data)) characters")
+                
+                # Display first 100 characters
+                if length(data) > 100
+                    log_trace("  First 100 characters: $(data[1:100])...")
+                else
+                    log_trace("  Content: $data")
+                end
+                
+                # Save to file
+                output_path = "./received_$dataname.txt"
+                write(output_path, data)
+                log_trace("Saved text to $output_path")
+            else
+                log_trace("Received unexpected data type for '$dataname': $(typeof(data))")
+            end
+        end
+    end
+    
+    # Keep listening for 10 seconds
+    sleep(120)  
+    NATS.drain(conn)
+end
+
+
+# Run the test
+println("Starting text transport test...")
+println("Note: This receiver will wait for messages from the sender.")
+println("Run test_julia_to_julia_text_sender.jl first to send test data.")
+
+# Run receiver
+println("testing smartreceive for text")
+test_text_receive()
+
+println("Test completed.")

test/test_julia_text_sender.jl

@@ -0,0 +1,120 @@
+#!/usr/bin/env julia
+# Test script for text transport testing
+# Tests sending 1 large and 1 small text from Julia serviceA to Julia serviceB
+# Uses NATSBridge.jl smartsend with "text" type
+
+using NATS, JSON, UUIDs, Dates, PrettyPrinting, DataFrames, Arrow, HTTP
+
+# Include the bridge module
+include("../src/NATSBridge.jl")
+using .NATSBridge
+
+# Configuration
+const SUBJECT = "/NATSBridge_text_test"
+const NATS_URL = "nats.yiem.cc"
+const FILESERVER_URL = "http://192.168.88.104:8080"
+
+# Create correlation ID for tracing
+correlation_id = string(uuid4())
+
+
+# ------------------------------------------------------------------------------------------------ #
+#                                        test text transfer                                        #
+# ------------------------------------------------------------------------------------------------ #
+
+
+# Helper: Log with correlation ID
+function log_trace(message)
+    timestamp = Dates.now()
+    println("[$timestamp] [Correlation: $correlation_id] $message")
+end
+
+
+# File upload handler for plik server
+function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
+    # Get upload ID
+    url_getUploadID = "$fileserver_url/upload"
+    headers = ["Content-Type" => "application/json"]
+    body = """{ "OneShot" : true }"""
+    httpResponse = HTTP.request("POST", url_getUploadID, headers, body; body_is_form=false)
+    responseJson = JSON.parse(String(httpResponse.body))
+    uploadid = responseJson["id"]
+    uploadtoken = responseJson["uploadToken"]
+    
+    # Upload file
+    file_multipart = HTTP.Multipart(dataname, IOBuffer(data), "application/octet-stream")
+    url_upload = "$fileserver_url/file/$uploadid"
+    headers = ["X-UploadToken" => uploadtoken]
+    
+    form = HTTP.Form(Dict("file" => file_multipart))
+    httpResponse = HTTP.post(url_upload, headers, form)
+    responseJson = JSON.parse(String(httpResponse.body))
+    
+    fileid = responseJson["id"]
+    url = "$fileserver_url/file/$uploadid/$fileid/$dataname"
+    
+    return Dict("status" => httpResponse.status, "uploadid" => uploadid, "fileid" => fileid, "url" => url)
+end
+
+
+# Sender: Send text via smartsend
+function test_text_send()
+    # Create a small text (will use direct transport)
+    small_text = "Hello, this is a small text message. Testing direct transport via NATS."
+    
+    # Create a large text (will use link transport if > 1MB)
+    # Generate a larger text (~2MB to ensure link transport)
+    large_text = join(["Line $i: This is a sample text line with some content to pad the size. " for i in 1:50000], "")
+    
+    # Test data 1: small text
+    data1 = ("small_text", small_text, "text")
+    
+    # Test data 2: large text
+    data2 = ("large_text", large_text, "text")
+    
+    # Use smartsend with text type
+    # For small text: will use direct transport (Base64 encoded UTF-8)
+    # For large text: will use link transport (uploaded to fileserver)
+    env, env_json_str = NATSBridge.smartsend(
+        SUBJECT,
+        [data1, data2];  # List of (dataname, data, type) tuples
+        broker_url = NATS_URL,
+        fileserver_url = FILESERVER_URL,
+        fileserver_upload_handler = plik_upload_handler,
+        size_threshold = 1_000_000,  # 1MB threshold
+        correlation_id = correlation_id,
+        msg_purpose = "chat",
+        sender_name = "text_sender",
+        receiver_name = "",
+        receiver_id = "",
+        reply_to = "",
+        reply_to_msg_id = "",
+        is_publish = true  # Publish the message to NATS
+    )
+    
+    log_trace("Sent message with $(length(env.payloads)) payloads")
+    
+    # Log transport type for each payload
+    for (i, payload) in enumerate(env.payloads)
+        log_trace("Payload $i ('$payload.dataname'):")
+        log_trace("  Transport: $(payload.transport)")
+        log_trace("  Type: $(payload.payload_type)")
+        log_trace("  Size: $(payload.size) bytes")
+        log_trace("  Encoding: $(payload.encoding)")
+        
+        if payload.transport == "link"
+            log_trace("  URL: $(payload.data)")
+        end
+    end
+end
+
+
+# Run the test
+println("Starting text transport test...")
+println("Correlation ID: $correlation_id")
+
+# Run sender
+println("start smartsend for text")
+test_text_send()
+
+println("Test completed.")

test/test_micropython_basic.py

@@ -0,0 +1,207 @@
+#!/usr/bin/env python3
+"""
+Basic functionality test for nats_bridge.py
+Tests the core classes and functions without NATS connection
+"""
+
+import sys
+import os
+
+# Add src to path for import
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))
+
+from nats_bridge import (
+    MessagePayload,
+    MessageEnvelope,
+    smartsend,
+    smartreceive,
+    log_trace,
+    generate_uuid,
+    get_timestamp,
+    _serialize_data,
+    _deserialize_data
+)
+import json
+
+
+def test_message_payload():
+    """Test MessagePayload class"""
+    print("\n=== Testing MessagePayload ===")
+    
+    # Test direct transport with text
+    payload1 = MessagePayload(
+        data="Hello World",
+        msg_type="text",
+        id="test-id-1",
+        dataname="message",
+        transport="direct",
+        encoding="base64",
+        size=11
+    )
+    
+    assert payload1.id == "test-id-1"
+    assert payload1.dataname == "message"
+    assert payload1.type == "text"
+    assert payload1.transport == "direct"
+    assert payload1.encoding == "base64"
+    assert payload1.size == 11
+    print("  [PASS] MessagePayload with text data")
+    
+    # Test link transport with URL
+    payload2 = MessagePayload(
+        data="http://example.com/file.txt",
+        msg_type="binary",
+        id="test-id-2",
+        dataname="file",
+        transport="link",
+        encoding="none",
+        size=1000
+    )
+    
+    assert payload2.transport == "link"
+    assert payload2.data == "http://example.com/file.txt"
+    print("  [PASS] MessagePayload with link transport")
+    
+    # Test to_dict method
+    payload_dict = payload1.to_dict()
+    assert "id" in payload_dict
+    assert "dataname" in payload_dict
+    assert "type" in payload_dict
+    assert "transport" in payload_dict
+    assert "data" in payload_dict
+    print("  [PASS] MessagePayload.to_dict() method")
+
+
+def test_message_envelope():
+    """Test MessageEnvelope class"""
+    print("\n=== Testing MessageEnvelope ===")
+    
+    # Create payloads
+    payload1 = MessagePayload("Hello", "text", id="p1", dataname="msg1")
+    payload2 = MessagePayload("http://example.com/file", "binary", id="p2", dataname="file", transport="link")
+    
+    # Create envelope
+    env = MessageEnvelope(
+        send_to="/test/subject",
+        payloads=[payload1, payload2],
+        correlation_id="test-correlation-id",
+        msg_id="test-msg-id",
+        msg_purpose="chat",
+        sender_name="test_sender",
+        receiver_name="test_receiver",
+        reply_to="/test/reply"
+    )
+    
+    assert env.send_to == "/test/subject"
+    assert env.correlation_id == "test-correlation-id"
+    assert env.msg_id == "test-msg-id"
+    assert env.msg_purpose == "chat"
+    assert len(env.payloads) == 2
+    print("  [PASS] MessageEnvelope creation")
+    
+    # Test to_json method
+    json_str = env.to_json()
+    json_data = json.loads(json_str)
+    assert json_data["sendTo"] == "/test/subject"
+    assert json_data["correlationId"] == "test-correlation-id"
+    assert json_data["msgPurpose"] == "chat"
+    assert len(json_data["payloads"]) == 2
+    print("  [PASS] MessageEnvelope.to_json() method")
+
+
+def test_serialize_data():
+    """Test _serialize_data function"""
+    print("\n=== Testing _serialize_data ===")
+    
+    # Test text serialization
+    text_bytes = _serialize_data("Hello", "text")
+    assert isinstance(text_bytes, bytes)
+    assert text_bytes == b"Hello"
+    print("  [PASS] Text serialization")
+    
+    # Test dictionary serialization
+    dict_data = {"key": "value", "number": 42}
+    dict_bytes = _serialize_data(dict_data, "dictionary")
+    assert isinstance(dict_bytes, bytes)
+    parsed = json.loads(dict_bytes.decode('utf-8'))
+    assert parsed["key"] == "value"
+    print("  [PASS] Dictionary serialization")
+    
+    # Test binary serialization
+    binary_data = b"\x00\x01\x02"
+    binary_bytes = _serialize_data(binary_data, "binary")
+    assert binary_bytes == b"\x00\x01\x02"
+    print("  [PASS] Binary serialization")
+    
+    # Test image serialization
+    image_data = bytes([1, 2, 3, 4, 5])
+    image_bytes = _serialize_data(image_data, "image")
+    assert image_bytes == image_data
+    print("  [PASS] Image serialization")
+
+
+def test_deserialize_data():
+    """Test _deserialize_data function"""
+    print("\n=== Testing _deserialize_data ===")
+    
+    # Test text deserialization
+    text_bytes = b"Hello"
+    text_data = _deserialize_data(text_bytes, "text", "test-correlation-id")
+    assert text_data == "Hello"
+    print("  [PASS] Text deserialization")
+    
+    # Test dictionary deserialization
+    dict_bytes = b'{"key": "value"}'
+    dict_data = _deserialize_data(dict_bytes, "dictionary", "test-correlation-id")
+    assert dict_data == {"key": "value"}
+    print("  [PASS] Dictionary deserialization")
+    
+    # Test binary deserialization
+    binary_data = b"\x00\x01\x02"
+    binary_result = _deserialize_data(binary_data, "binary", "test-correlation-id")
+    assert binary_result == b"\x00\x01\x02"
+    print("  [PASS] Binary deserialization")
+
+
+def test_utilities():
+    """Test utility functions"""
+    print("\n=== Testing Utility Functions ===")
+    
+    # Test generate_uuid
+    uuid1 = generate_uuid()
+    uuid2 = generate_uuid()
+    assert uuid1 != uuid2
+    print(f"  [PASS] generate_uuid() - generated: {uuid1}")
+    
+    # Test get_timestamp
+    timestamp = get_timestamp()
+    assert "T" in timestamp
+    print(f"  [PASS] get_timestamp() - generated: {timestamp}")
+
+
+def main():
+    """Run all tests"""
+    print("=" * 60)
+    print("NATSBridge Python/Micropython - Basic Functionality Tests")
+    print("=" * 60)
+    
+    try:
+        test_message_payload()
+        test_message_envelope()
+        test_serialize_data()
+        test_deserialize_data()
+        test_utilities()
+        
+        print("\n" + "=" * 60)
+        print("ALL TESTS PASSED!")
+        print("=" * 60)
+        
+    except Exception as e:
+        print(f"\n[FAIL] Test failed with error: {e}")
+        import traceback
+        traceback.print_exc()
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()

test/test_micropython_dict_receiver.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+"""
+Test script for dictionary transport testing - Receiver
+Tests receiving dictionary messages via NATS using nats_bridge.py smartreceive
+"""
+
+import sys
+import os
+import json
+
+# Add src to path for import
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))
+
+from nats_bridge import smartreceive, log_trace
+import nats
+import asyncio
+
+# Configuration
+SUBJECT = "/NATSBridge_dict_test"
+NATS_URL = "nats://nats.yiem.cc:4222"
+
+
+async def main():
+    log_trace("", f"Starting dictionary transport receiver test...")
+    log_trace("", f"Note: This receiver will wait for messages from the sender.")
+    log_trace("", f"Run test_micropython_dict_sender.py first to send test data.")
+    
+    # Connect to NATS
+    nc = await nats.connect(NATS_URL)
+    log_trace("", f"Connected to NATS at {NATS_URL}")
+    
+    # Subscribe to the subject
+    async def message_handler(msg):
+        log_trace("", f"Received message on {msg.subject}")
+        
+        # Use smartreceive to handle the data
+        result = smartreceive(msg.data)
+        
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
+        for dataname, data, data_type in result["payloads"]:
+            if isinstance(data, dict):
+                log_trace(result.get("correlationId", ""), f"Received dictionary '{dataname}' of type {data_type}")
+                log_trace(result.get("correlationId", ""), f"  Keys: {list(data.keys())}")
+                
+                # Display first few items for small dicts
+                if isinstance(data, dict) and len(data) <= 10:
+                    log_trace(result.get("correlationId", ""), f"  Content: {json.dumps(data, indent=2)}")
+                else:
+                    # For large dicts, show summary
+                    log_trace(result.get("correlationId", ""), f"  Summary: {json.dumps(data, default=str)[:200]}...")
+                
+                # Save to file
+                output_path = f"./received_{dataname}.json"
+                with open(output_path, 'w') as f:
+                    json.dump(data, f, indent=2)
+                log_trace(result.get("correlationId", ""), f"Saved dictionary to {output_path}")
+            else:
+                log_trace(result.get("correlationId", ""), f"Received unexpected data type for '{dataname}': {type(data)}")
+    
+    sid = await nc.subscribe(SUBJECT, cb=message_handler)
+    log_trace("", f"Subscribed to {SUBJECT} with subscription ID: {sid}")
+    
+    # Keep listening for 120 seconds
+    await asyncio.sleep(120)
+    await nc.close()
+    log_trace("", "Test completed.")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())

test/test_micropython_dict_sender.py

@@ -0,0 +1,100 @@
+#!/usr/bin/env python3
+"""
+Test script for dictionary transport testing - Micropython
+Tests sending dictionary messages via NATS using nats_bridge.py smartsend
+"""
+
+import sys
+import os
+
+# Add src to path for import
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))
+
+from nats_bridge import smartsend, log_trace
+import uuid
+
+# Configuration
+SUBJECT = "/NATSBridge_dict_test"
+NATS_URL = "nats://nats.yiem.cc:4222"
+FILESERVER_URL = "http://192.168.88.104:8080"
+SIZE_THRESHOLD = 1_000_000  # 1MB
+
+# Create correlation ID for tracing
+correlation_id = str(uuid.uuid4())
+
+
+def main():
+    # Create a small dictionary (will use direct transport)
+    small_dict = {
+        "name": "test",
+        "value": 42,
+        "enabled": True,
+        "metadata": {
+            "version": "1.0.0",
+            "timestamp": "2026-02-22T12:00:00Z"
+        }
+    }
+    
+    # Create a large dictionary (will use link transport if > 1MB)
+    # Generate a larger dictionary (~2MB to ensure link transport)
+    large_dict = {
+        "id": str(uuid.uuid4()),
+        "items": [
+            {
+                "index": i,
+                "name": f"item_{i}",
+                "value": i * 1.5,
+                "data": "x" * 10000  # Large string per item
+            }
+            for i in range(200)
+        ],
+        "metadata": {
+            "count": 200,
+            "created": "2026-02-22T12:00:00Z"
+        }
+    }
+    
+    # Test data 1: small dictionary
+    data1 = ("small_dict", small_dict, "dictionary")
+    
+    # Test data 2: large dictionary
+    data2 = ("large_dict", large_dict, "dictionary")
+    
+    log_trace(correlation_id, f"Starting smartsend for subject: {SUBJECT}")
+    log_trace(correlation_id, f"Correlation ID: {correlation_id}")
+    
+    # Use smartsend with dictionary type
+    env, env_json_str = smartsend(
+        SUBJECT,
+        [data1, data2],  # List of (dataname, data, type) tuples
+        nats_url=NATS_URL,
+        fileserver_url=FILESERVER_URL,
+        size_threshold=SIZE_THRESHOLD,
+        correlation_id=correlation_id,
+        msg_purpose="chat",
+        sender_name="dict_sender",
+        receiver_name="",
+        receiver_id="",
+        reply_to="",
+        reply_to_msg_id="",
+        is_publish=True  # Publish the message to NATS
+    )
+    
+    log_trace(correlation_id, f"Sent message with {len(env.payloads)} payloads")
+    
+    # Log transport type for each payload
+    for i, payload in enumerate(env.payloads):
+        log_trace(correlation_id, f"Payload {i+1} ('{payload.dataname}'):")
+        log_trace(correlation_id, f"  Transport: {payload.transport}")
+        log_trace(correlation_id, f"  Type: {payload.type}")
+        log_trace(correlation_id, f"  Size: {payload.size} bytes")
+        log_trace(correlation_id, f"  Encoding: {payload.encoding}")
+        
+        if payload.transport == "link":
+            log_trace(correlation_id, f"  URL: {payload.data}")
+    
+    print(f"Test completed. Correlation ID: {correlation_id}")
+
+
+if __name__ == "__main__":
+    main()

test/test_micropython_file_receiver.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+"""
+Test script for file transport testing - Receiver
+Tests receiving binary files via NATS using nats_bridge.py smartreceive
+"""
+
+import sys
+import os
+
+# Add src to path for import
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))
+
+from nats_bridge import smartreceive, log_trace
+import nats
+import asyncio
+
+# Configuration
+SUBJECT = "/NATSBridge_file_test"
+NATS_URL = "nats://nats.yiem.cc:4222"
+
+
+async def main():
+    log_trace("", f"Starting file transport receiver test...")
+    log_trace("", f"Note: This receiver will wait for messages from the sender.")
+    log_trace("", f"Run test_micropython_file_sender.py first to send test data.")
+    
+    # Connect to NATS
+    nc = await nats.connect(NATS_URL)
+    log_trace("", f"Connected to NATS at {NATS_URL}")
+    
+    # Subscribe to the subject
+    async def message_handler(msg):
+        log_trace("", f"Received message on {msg.subject}")
+        
+        # Use smartreceive to handle the data
+        result = smartreceive(msg.data)
+        
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
+        for dataname, data, data_type in result["payloads"]:
+            if isinstance(data, bytes):
+                log_trace(result.get("correlationId", ""), f"Received binary '{dataname}' of type {data_type}")
+                log_trace(result.get("correlationId", ""), f"  Size: {len(data)} bytes")
+                
+                # Display first 100 bytes as hex
+                log_trace(result.get("correlationId", ""), f"  First 100 bytes (hex): {data[:100].hex()}")
+                
+                # Save to file
+                output_path = f"./received_{dataname}.bin"
+                with open(output_path, 'wb') as f:
+                    f.write(data)
+                log_trace(result.get("correlationId", ""), f"Saved binary to {output_path}")
+            else:
+                log_trace(result.get("correlationId", ""), f"Received unexpected data type for '{dataname}': {type(data)}")
+    
+    sid = await nc.subscribe(SUBJECT, cb=message_handler)
+    log_trace("", f"Subscribed to {SUBJECT} with subscription ID: {sid}")
+    
+    # Keep listening for 120 seconds
+    await asyncio.sleep(120)
+    await nc.close()
+    log_trace("", "Test completed.")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())

test/test_micropython_file_sender.py

@@ -0,0 +1,80 @@
+#!/usr/bin/env python3
+"""
+Test script for file transport testing - Micropython
+Tests sending binary files via NATS using nats_bridge.py smartsend
+"""
+
+import sys
+import os
+
+# Add src to path for import
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))
+
+from nats_bridge import smartsend, log_trace
+import uuid
+
+# Configuration
+SUBJECT = "/NATSBridge_file_test"
+NATS_URL = "nats://nats.yiem.cc:4222"
+FILESERVER_URL = "http://192.168.88.104:8080"
+SIZE_THRESHOLD = 1_000_000  # 1MB
+
+# Create correlation ID for tracing
+correlation_id = str(uuid.uuid4())
+
+
+def main():
+    # Create small binary data (will use direct transport)
+    small_binary = b"This is small binary data for testing direct transport."
+    small_binary += b"\x00" * 100  # Add some null bytes
+    
+    # Create large binary data (will use link transport if > 1MB)
+    # Generate a larger binary (~2MB to ensure link transport)
+    large_binary = bytes([
+        (i * 7) % 256 for i in range(2_000_000)
+    ])
+    
+    # Test data 1: small binary (direct transport)
+    data1 = ("small_binary", small_binary, "binary")
+    
+    # Test data 2: large binary (link transport)
+    data2 = ("large_binary", large_binary, "binary")
+    
+    log_trace(correlation_id, f"Starting smartsend for subject: {SUBJECT}")
+    log_trace(correlation_id, f"Correlation ID: {correlation_id}")
+    
+    # Use smartsend with binary type
+    env, env_json_str = smartsend(
+        SUBJECT,
+        [data1, data2],  # List of (dataname, data, type) tuples
+        nats_url=NATS_URL,
+        fileserver_url=FILESERVER_URL,
+        size_threshold=SIZE_THRESHOLD,
+        correlation_id=correlation_id,
+        msg_purpose="chat",
+        sender_name="file_sender",
+        receiver_name="",
+        receiver_id="",
+        reply_to="",
+        reply_to_msg_id="",
+        is_publish=True  # Publish the message to NATS
+    )
+    
+    log_trace(correlation_id, f"Sent message with {len(env.payloads)} payloads")
+    
+    # Log transport type for each payload
+    for i, payload in enumerate(env.payloads):
+        log_trace(correlation_id, f"Payload {i+1} ('{payload.dataname}'):")
+        log_trace(correlation_id, f"  Transport: {payload.transport}")
+        log_trace(correlation_id, f"  Type: {payload.type}")
+        log_trace(correlation_id, f"  Size: {payload.size} bytes")
+        log_trace(correlation_id, f"  Encoding: {payload.encoding}")
+        
+        if payload.transport == "link":
+            log_trace(correlation_id, f"  URL: {payload.data}")
+    
+    print(f"Test completed. Correlation ID: {correlation_id}")
+
+
+if __name__ == "__main__":
+    main()

test/test_micropython_mixed_receiver.py

@@ -0,0 +1,97 @@
+#!/usr/bin/env python3
+"""
+Test script for mixed payload testing - Receiver
+Tests receiving mixed payload types via NATS using nats_bridge.py smartreceive
+"""
+
+import sys
+import os
+import json
+
+# Add src to path for import
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))
+
+from nats_bridge import smartreceive, log_trace
+import nats
+import asyncio
+
+# Configuration
+SUBJECT = "/NATSBridge_mixed_test"
+NATS_URL = "nats://nats.yiem.cc:4222"
+
+
+async def main():
+    log_trace("", f"Starting mixed payload receiver test...")
+    log_trace("", f"Note: This receiver will wait for messages from the sender.")
+    log_trace("", f"Run test_micropython_mixed_sender.py first to send test data.")
+    
+    # Connect to NATS
+    nc = await nats.connect(NATS_URL)
+    log_trace("", f"Connected to NATS at {NATS_URL}")
+    
+    # Subscribe to the subject
+    async def message_handler(msg):
+        log_trace("", f"Received message on {msg.subject}")
+        
+        # Use smartreceive to handle the data
+        result = smartreceive(msg.data)
+        
+        log_trace(result.get("correlationId", ""), f"Received envelope with {len(result['payloads'])} payloads")
+        
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
+        for dataname, data, data_type in result["payloads"]:
+            log_trace(result.get("correlationId", ""), f"\n--- Payload: {dataname} (type: {data_type}) ---")
+            
+            if isinstance(data, str):
+                log_trace(result.get("correlationId", ""), f"  Type: text/string")
+                log_trace(result.get("correlationId", ""), f"  Length: {len(data)} characters")
+                if len(data) <= 100:
+                    log_trace(result.get("correlationId", ""), f"  Content: {data}")
+                else:
+                    log_trace(result.get("correlationId", ""), f"  First 100 chars: {data[:100]}...")
+                # Save to file
+                output_path = f"./received_{dataname}.txt"
+                with open(output_path, 'w') as f:
+                    f.write(data)
+                log_trace(result.get("correlationId", ""), f"  Saved to: {output_path}")
+                
+            elif isinstance(data, dict):
+                log_trace(result.get("correlationId", ""), f"  Type: dictionary")
+                log_trace(result.get("correlationId", ""), f"  Keys: {list(data.keys())}")
+                log_trace(result.get("correlationId", ""), f"  Content: {json.dumps(data, indent=2)}")
+                # Save to file
+                output_path = f"./received_{dataname}.json"
+                with open(output_path, 'w') as f:
+                    json.dump(data, f, indent=2)
+                log_trace(result.get("correlationId", ""), f"  Saved to: {output_path}")
+                
+            elif isinstance(data, bytes):
+                log_trace(result.get("correlationId", ""), f"  Type: binary")
+                log_trace(result.get("correlationId", ""), f"  Size: {len(data)} bytes")
+                log_trace(result.get("correlationId", ""), f"  First 100 bytes (hex): {data[:100].hex()}")
+                # Save to file
+                output_path = f"./received_{dataname}.bin"
+                with open(output_path, 'wb') as f:
+                    f.write(data)
+                log_trace(result.get("correlationId", ""), f"  Saved to: {output_path}")
+            else:
+                log_trace(result.get("correlationId", ""), f"  Received unexpected data type: {type(data)}")
+        
+        # Log envelope metadata
+        log_trace(result.get("correlationId", ""), f"\n--- Envelope Metadata ---")
+        log_trace(result.get("correlationId", ""), f"  Correlation ID: {result.get('correlationId', 'N/A')}")
+        log_trace(result.get("correlationId", ""), f"  Message ID: {result.get('msgId', 'N/A')}")
+        log_trace(result.get("correlationId", ""), f"  Sender: {result.get('senderName', 'N/A')}")
+        log_trace(result.get("correlationId", ""), f"  Purpose: {result.get('msgPurpose', 'N/A')}")
+    
+    sid = await nc.subscribe(SUBJECT, cb=message_handler)
+    log_trace("", f"Subscribed to {SUBJECT} with subscription ID: {sid}")
+    
+    # Keep listening for 120 seconds
+    await asyncio.sleep(120)
+    await nc.close()
+    log_trace("", "Test completed.")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())

test/test_micropython_mixed_sender.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+"""
+Test script for mixed payload testing - Micropython
+Tests sending mixed payload types via NATS using nats_bridge.py smartsend
+"""
+
+import sys
+import os
+
+# Add src to path for import
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))
+
+from nats_bridge import smartsend, log_trace
+import uuid
+
+# Configuration
+SUBJECT = "/NATSBridge_mixed_test"
+NATS_URL = "nats://nats.yiem.cc:4222"
+FILESERVER_URL = "http://192.168.88.104:8080"
+SIZE_THRESHOLD = 1_000_000  # 1MB
+
+# Create correlation ID for tracing
+correlation_id = str(uuid.uuid4())
+
+
+def main():
+    # Create payloads for mixed content test
+    
+    # 1. Small text (direct transport)
+    text_data = "Hello, this is a text message for testing mixed payloads!"
+    
+    # 2. Small dictionary (direct transport)
+    dict_data = {
+        "status": "ok",
+        "code": 200,
+        "message": "Test successful",
+        "items": [1, 2, 3]
+    }
+    
+    # 3. Small binary (direct transport)
+    binary_data = b"\x00\x01\x02\x03\x04\x05" + b"\xff" * 100
+    
+    # 4. Large text (link transport - will use fileserver)
+    large_text = "\n".join([
+        f"Line {i}: This is a large text payload for link transport testing. " * 50
+        for i in range(100)
+    ])
+    
+    # Test data list - mixed payload types
+    data = [
+        ("message_text", text_data, "text"),
+        ("config_dict", dict_data, "dictionary"),
+        ("small_binary", binary_data, "binary"),
+        ("large_text", large_text, "text"),
+    ]
+    
+    log_trace(correlation_id, f"Starting smartsend for subject: {SUBJECT}")
+    log_trace(correlation_id, f"Correlation ID: {correlation_id}")
+    
+    # Use smartsend with mixed types
+    env, env_json_str = smartsend(
+        SUBJECT,
+        data,  # List of (dataname, data, type) tuples
+        nats_url=NATS_URL,
+        fileserver_url=FILESERVER_URL,
+        size_threshold=SIZE_THRESHOLD,
+        correlation_id=correlation_id,
+        msg_purpose="chat",
+        sender_name="mixed_sender",
+        receiver_name="",
+        receiver_id="",
+        reply_to="",
+        reply_to_msg_id="",
+        is_publish=True  # Publish the message to NATS
+    )
+    
+    log_trace(correlation_id, f"Sent message with {len(env.payloads)} payloads")
+    
+    # Log transport type for each payload
+    for i, payload in enumerate(env.payloads):
+        log_trace(correlation_id, f"Payload {i+1} ('{payload.dataname}'):")
+        log_trace(correlation_id, f"  Transport: {payload.transport}")
+        log_trace(correlation_id, f"  Type: {payload.type}")
+        log_trace(correlation_id, f"  Size: {payload.size} bytes")
+        log_trace(correlation_id, f"  Encoding: {payload.encoding}")
+        
+        if payload.transport == "link":
+            log_trace(correlation_id, f"  URL: {payload.data}")
+    
+    print(f"Test completed. Correlation ID: {correlation_id}")
+
+
+if __name__ == "__main__":
+    main()

test/test_micropython_text_receiver.py

@@ -0,0 +1,69 @@
+#!/usr/bin/env python3
+"""
+Test script for text transport testing - Receiver
+Tests receiving text messages via NATS using nats_bridge.py smartreceive
+"""
+
+import sys
+import os
+import json
+
+# Add src to path for import
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))
+
+from nats_bridge import smartreceive, log_trace
+import nats
+import asyncio
+
+# Configuration
+SUBJECT = "/NATSBridge_text_test"
+NATS_URL = "nats://nats.yiem.cc:4222"
+
+
+async def main():
+    log_trace("", f"Starting text transport receiver test...")
+    log_trace("", f"Note: This receiver will wait for messages from the sender.")
+    log_trace("", f"Run test_micropython_text_sender.py first to send test data.")
+    
+    # Connect to NATS
+    nc = await nats.connect(NATS_URL)
+    log_trace("", f"Connected to NATS at {NATS_URL}")
+    
+    # Subscribe to the subject
+    async def message_handler(msg):
+        log_trace("", f"Received message on {msg.subject}")
+        
+        # Use smartreceive to handle the data
+        result = smartreceive(msg.data)
+        
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
+        for dataname, data, data_type in result["payloads"]:
+            if isinstance(data, str):
+                log_trace(result.get("correlationId", ""), f"Received text '{dataname}' of type {data_type}")
+                log_trace(result.get("correlationId", ""), f"  Length: {len(data)} characters")
+                
+                # Display first 100 characters
+                if len(data) > 100:
+                    log_trace(result.get("correlationId", ""), f"  First 100 characters: {data[:100]}...")
+                else:
+                    log_trace(result.get("correlationId", ""), f"  Content: {data}")
+                
+                # Save to file
+                output_path = f"./received_{dataname}.txt"
+                with open(output_path, 'w') as f:
+                    f.write(data)
+                log_trace(result.get("correlationId", ""), f"Saved text to {output_path}")
+            else:
+                log_trace(result.get("correlationId", ""), f"Received unexpected data type for '{dataname}': {type(data)}")
+    
+    sid = await nc.subscribe(SUBJECT, cb=message_handler)
+    log_trace("", f"Subscribed to {SUBJECT} with subscription ID: {sid}")
+    
+    # Keep listening for 120 seconds
+    await asyncio.sleep(120)
+    await nc.close()
+    log_trace("", "Test completed.")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())

test/test_micropython_text_sender.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+"""
+Test script for text transport testing - Micropython
+Tests sending text messages via NATS using nats_bridge.py smartsend
+"""
+
+import sys
+import os
+
+# Add src to path for import
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'src'))
+
+from nats_bridge import smartsend, log_trace
+import uuid
+
+# Configuration
+SUBJECT = "/NATSBridge_text_test"
+NATS_URL = "nats://nats.yiem.cc:4222"
+FILESERVER_URL = "http://192.168.88.104:8080"
+SIZE_THRESHOLD = 1_000_000  # 1MB
+
+# Create correlation ID for tracing
+correlation_id = str(uuid.uuid4())
+
+
+def main():
+    # Create a small text (will use direct transport)
+    small_text = "Hello, this is a small text message. Testing direct transport via NATS."
+    
+    # Create a large text (will use link transport if > 1MB)
+    # Generate a larger text (~2MB to ensure link transport)
+    large_text = "\n".join([
+        f"Line {i}: This is a sample text line with some content to pad the size. " * 100 
+        for i in range(500)
+    ])
+    
+    # Test data 1: small text
+    data1 = ("small_text", small_text, "text")
+    
+    # Test data 2: large text
+    data2 = ("large_text", large_text, "text")
+    
+    log_trace(correlation_id, f"Starting smartsend for subject: {SUBJECT}")
+    log_trace(correlation_id, f"Correlation ID: {correlation_id}")
+    
+    # Use smartsend with text type
+    # For small text: will use direct transport (Base64 encoded UTF-8)
+    # For large text: will use link transport (uploaded to fileserver)
+    env, env_json_str = smartsend(
+        SUBJECT,
+        [data1, data2],  # List of (dataname, data, type) tuples
+        nats_url=NATS_URL,
+        fileserver_url=FILESERVER_URL,
+        size_threshold=SIZE_THRESHOLD,
+        correlation_id=correlation_id,
+        msg_purpose="chat",
+        sender_name="text_sender",
+        receiver_name="",
+        receiver_id="",
+        reply_to="",
+        reply_to_msg_id="",
+        is_publish=True  # Publish the message to NATS
+    )
+    
+    log_trace(correlation_id, f"Sent message with {len(env.payloads)} payloads")
+    
+    # Log transport type for each payload
+    for i, payload in enumerate(env.payloads):
+        log_trace(correlation_id, f"Payload {i+1} ('{payload.dataname}'):")
+        log_trace(correlation_id, f"  Transport: {payload.transport}")
+        log_trace(correlation_id, f"  Type: {payload.type}")
+        log_trace(correlation_id, f"  Size: {payload.size} bytes")
+        log_trace(correlation_id, f"  Encoding: {payload.encoding}")
+        
+        if payload.transport == "link":
+            log_trace(correlation_id, f"  URL: {payload.data}")
+    
+    print(f"Test completed. Correlation ID: {correlation_id}")
+
+
+if __name__ == "__main__":
+    main()