Merge pull request 'smartreceive_return_envelope' (#7) from smartreceive_return_envelope into main

Reviewed-on: #7

Manifest.toml

@@ -2,7 +2,7 @@
 
 julia_version = "1.12.5"
 manifest_format = "2.0"
-project_hash = "8a7a8b88d777403234a6816e699fb0ab1e991aac"
+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"

Project.toml

@@ -1,5 +1,11 @@
+name = "NATSBridge"
+uuid = "f2724d33-f338-4a57-b9f8-1be882570d10"
+version = "0.4.2"
+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"
@@ -9,3 +15,7 @@ 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"

docs/architecture.md

@@ -1,8 +1,13 @@
-# 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
 
@@ -35,8 +40,24 @@ The system uses a **standardized list-of-tuples format** for all payload operati
 # Input format for smartsend (always a list of tuples with type info)
 [(dataname1, data1, type1), (dataname2, data2, type2), ...]
 
-# Output format for smartreceive (always returns a list of tuples)
+# Output format for smartreceive (returns envelope dictionary with payloads field)
-[(dataname1, data1, type1), (dataname2, data2, type2), ...]
+# Returns: Dict with envelope metadata and payloads field containing list of tuples
+# {
+#   "correlationId": "...",
+#   "msgId": "...",
+#   "timestamp": "...",
+#   "sendTo": "...",
+#   "msgPurpose": "...",
+#   "senderName": "...",
+#   "senderId": "...",
+#   "receiverName": "...",
+#   "receiverId": "...",
+#   "replyTo": "...",
+#   "replyToMsgId": "...",
+#   "brokerURL": "...",
+#   "metadata": {...},
+#   "payloads": [(dataname1, data1, type1), (dataname2, data2, type2), ...]
+# }
 ```
 
 **Supported Types:**
@@ -81,9 +102,10 @@ smartsend(
     nats_url="nats://localhost:4222"
 )
 
-# Receive always returns a list
+# Receive returns a dictionary envelope with all metadata and deserialized payloads
-payloads = smartreceive(msg, fileserverDownloadHandler, max_retries, base_delay, max_delay)
+envelope = smartreceive(msg, fileserverDownloadHandler, max_retries, base_delay, max_delay)
-# payloads = [("dataname1", data1, type1), ("dataname2", data2, type2), ...]
+# envelope["payloads"] = [("dataname1", data1, type1), ("dataname2", data2, type2), ...]
+# envelope["correlationId"], envelope["msgId"], etc.
 ```
 
 ## Architecture Diagram
@@ -118,7 +140,7 @@ flowchart TD
 
 ### 1. msgEnvelope_v1 - Message Envelope
 
-The `msgEnvelope_v1` structure provides a comprehensive message format for bidirectional communication between Julia and JavaScript services.
+The `msgEnvelope_v1` structure provides a comprehensive message format for bidirectional communication between Julia, JavaScript, and Python/Micropython applications.
 
 **Julia Structure:**
 ```julia
@@ -194,7 +216,7 @@ end
 
 ### 2. msgPayload_v1 - Payload Structure
 
-The `msgPayload_v1` structure provides flexible payload handling for various data types.
+The `msgPayload_v1` structure provides flexible payload handling for various data types across all supported platforms.
 
 **Julia Structure:**
 ```julia
@@ -222,15 +244,15 @@ end
 ┌─────────────────────────────────────────────────────────────┐
 │                     smartsend Function                      │
 │  Accepts: [(dataname1, data1, type1), ...]                  │
-│  (No standalone type parameter - type per payload)          │
+│  (Type is per payload, not standalone)                      │
 └─────────────────────────────────────────────────────────────┘
                              │
                              ▼
 ┌─────────────────────────────────────────────────────────────┐
 │  For each payload:                                          │
-│  1. Extract type from tuple                                │
+│  1. Extract type from tuple                                 │
-│  2. Serialize based on type                                │
+│  2. Serialize based on type                                 │
-│  3. Check payload size                                     │
+│  3. Check payload size                                      │
 └─────────────────────────────────────────────────────────────┘
                              │
             ┌────────────────┴─-────────────────┐
@@ -249,19 +271,77 @@ end
       └─────────────────┘                 └─────────────────┘
 ```
 
-### 4. 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
+    subgraph PyModule
-        smartsendJulia[smartsend Julia]
+        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
@@ -269,19 +349,19 @@ graph TD
     style JuliaModule fill:#c5e1a5
 ```
 
-### 5. JavaScript Module Architecture
+### 7. JavaScript Module Architecture
 
 ```mermaid
 graph TD
     subgraph JSModule
-        smartsendJS[smartsend JS]
+        JSSmartSend[smartsend]
-        smartreceiveJS[smartreceive JS]
+        JSSmartReceive[smartreceive]
         JetStreamConsumer[JetStream Pull Consumer]
         ApacheArrow[Apache Arrow]
     end
 
-    smartsendJS --> NATS
+    JSSmartSend --> NATS
-    smartreceiveJS --> JetStreamConsumer
+    JSSmartReceive --> JetStreamConsumer
     JetStreamConsumer --> ApacheArrow
 
     style JSModule fill:#f3e5f5
@@ -338,23 +418,25 @@ function smartreceive(
     #   If direct: decode Base64 payload
     #   If link: fetch from URL with exponential backoff using fileserverDownloadHandler
     # Deserialize payload based on type
-    # Return list of (dataname, data, type) tuples
+    # Return envelope dictionary with all metadata and deserialized payloads
 end
 ```
 
 **Output Format:**
-- Always returns a list of tuples: `[(dataname1, data1, type1), (dataname2, data2, type2), ...]`
+- Returns a dictionary (key-value map) containing all envelope fields:
-- Even for single payloads: `[(dataname1, data1, type1)]`
+  - `correlationId`, `msgId`, `timestamp`, `sendTo`, `msgPurpose`, `senderName`, `senderId`, `receiverName`, `receiverId`, `replyTo`, `replyToMsgId`, `brokerURL`
+  - `metadata` - Message-level metadata dictionary
+  - `payloads` - List of dictionaries, each containing deserialized payload data
 
 **Process Flow:**
-1. Parse the JSON envelope to extract the `payloads` array
+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 `fileserverDownloadHandler`)
    - Deserialize based on payload type (`dictionary`, `table`, `binary`, etc.)
-4. Return list of `(dataname, data, type)` tuples
+4. Return envelope dictionary with `payloads` field containing list of `(dataname, data, type)` tuples
 
 **Note:** The `fileserverDownloadHandler` receives `(url::String, max_retries::Int, base_delay::Int, max_delay::Int, correlation_id::String)` and returns `Vector{UInt8}`.
 
@@ -401,21 +483,27 @@ async function smartreceive(msg, options = {})
     // - correlationId: optional correlation ID for tracing
 ```
 
+**Output Format:**
+- Returns a dictionary (key-value map) containing all envelope fields:
+  - `correlationId`, `msgId`, `timestamp`, `sendTo`, `msgPurpose`, `senderName`, `senderId`, `receiverName`, `receiverId`, `replyTo`, `replyToMsgId`, `brokerURL`
+  - `metadata` - Message-level metadata dictionary
+  - `payloads` - List of dictionaries, each containing deserialized payload data
+
 **Process Flow:**
-1. Parse the JSON envelope to extract the `payloads` array
+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
    - Deserialize based on payload type (`dictionary`, `table`, `binary`, etc.)
-4. Return list of `(dataname, data, type)` tuples
+4. Return envelope dictionary with `payloads` field containing list of `(dataname, data, type)` tuples
 
 ## Scenario Implementations
 
 ### Scenario 1: Command & Control (Small Dictionary)
 
-**Julia (Receiver):**
+**Julia (Sender/Receiver):**
 ```julia
 # Subscribe to control subject
 # Parse JSON envelope
@@ -423,15 +511,21 @@ async function smartreceive(msg, options = {})
 # Send acknowledgment
 ```
 
-**JavaScript (Sender):**
+**JavaScript (Sender/Receiver):**
 ```javascript
 // 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
@@ -440,7 +534,7 @@ 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
@@ -448,42 +542,64 @@ 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"
 ```
 
-**Julia (Receiver):**
+**Julia (Sender/Receiver):**
 ```julia
-// Receive audio data
+# Receive audio data
-// Perform FFT or AI transcription
+# Perform FFT or AI transcription
-// Send results back (JSON + Arrow table)
+# 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, Julia to JavaScript. The Action: Julia wants to send a small DataFrame to show on a JavaScript dashboard for the user to choose.
+**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):**
+**Julia (Sender/Receiver):**
 ```julia
 # Create small DataFrame (e.g., 50KB - 500KB)
 # Convert to Arrow IPC stream
@@ -492,7 +608,7 @@ async function smartreceive(msg, options = {})
 # Include metadata for dashboard selection context
 ```
 
-**JavaScript (Receiver):**
+**JavaScript (Sender/Receiver):**
 ```javascript
 // Receive NATS message with direct transport
 // Decode Base64 payload
@@ -502,11 +618,20 @@ async function smartreceive(msg, options = {})
 // Send selection back to Julia
 ```
 
-**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.
+**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.
+**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.
 
@@ -545,7 +670,25 @@ async function smartreceive(msg, options = {})
 // Support bidirectional reply with claim-check delivery confirmation
 ```
 
-**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.
+**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.
 

docs/implementation.md

@@ -2,7 +2,22 @@
 
 ## 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.
+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 |
 
 ### Multi-Payload Support
 
@@ -13,8 +28,24 @@ The implementation uses a **standardized list-of-tuples format** for all payload
 # Input format for smartsend (always a list of tuples with type info)
 [(dataname1, data1, type1), (dataname2, data2, type2), ...]
 
-# Output format for smartreceive (always returns a list of tuples with type info)
+# Output format for smartreceive (returns envelope dictionary with payloads field)
-[(dataname1, data1, type1), (dataname2, data2, type2), ...]
+# Returns: Dict with envelope metadata and payloads field containing list of tuples
+# {
+#   "correlationId": "...",
+#   "msgId": "...",
+#   "timestamp": "...",
+#   "sendTo": "...",
+#   "msgPurpose": "...",
+#   "senderName": "...",
+#   "senderId": "...",
+#   "receiverName": "...",
+#   "receiverId": "...",
+#   "replyTo": "...",
+#   "replyToMsgId": "...",
+#   "brokerURL": "...",
+#   "metadata": {...},
+#   "payloads": [(dataname1, data1, type1), (dataname2, data2, type2), ...]
+# }
 ```
 
 Where `type` can be: `"text"`, `"dictionary"`, `"table"`, `"image"`, `"audio"`, `"video"`, `"binary"`
@@ -27,49 +58,103 @@ smartsend("/test", [(dataname1, data1, "text")], ...)
 # Multiple payloads in one message (each payload has its own type)
 smartsend("/test", [(dataname1, data1, "dictionary"), (dataname2, data2, "table")], ...)
 
-# Receive always returns a list with type info
+# Receive returns a dictionary envelope with all metadata and deserialized payloads
-payloads = smartreceive(msg, ...)
+envelope = smartreceive(msg, ...)
-# payloads = [(dataname1, data1, "text"), (dataname2, data2, "table"), ...]
+# envelope["payloads"] = [(dataname1, data1, "text"), (dataname2, data2, "table"), ...]
+# envelope["correlationId"], envelope["msgId"], etc.
 ```
 
+## 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, nats_url="nats://localhost:4222")
+```
+
+```javascript
+// JavaScript receiver
+const { smartreceive } = require('./src/NATSBridge');
+const envelope = await smartreceive(msg);
+// envelope.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
 
-The implementation follows the Claim-Check pattern:
+All three implementations (Julia, JavaScript, Python/Micropython) follow the same Claim-Check pattern:
 
 ```
 ┌─────────────────────────────────────────────────────────────────────────┐
 │                         SmartSend Function                              │
 └─────────────────────────────────────────────────────────────────────────┘
-                             │
+                              │
-                             ▼
+                              ▼
 ┌─────────────────────────────────────────────────────────────────────────┐
 │  Is payload size < 1MB?                                                 │
 └─────────────────────────────────────────────────────────────────────────┘
-                             │
+                              │
-           ┌─────────────────┴─────────────────┐
+            ┌─────────────────┴─────────────────┐
-           ▼                                   ▼
+            ▼                                   ▼
-     ┌─────────────────┐                 ┌─────────────────┐
+      ┌─────────────────┐                 ┌─────────────────┐
-     │  Direct Path    │                 │  Link Path      │
+      │  Direct Path    │                 │  Link Path      │
-     │  (< 1MB)        │                 │  (> 1MB)        │
+      │  (< 1MB)        │                 │  (> 1MB)        │
-     │                 │                 │                 │
+      │                 │                 │                 │
-     │ • Serialize to  │                 │ • Serialize to  │
+      │ • Serialize to  │                 │ • Serialize to  │
-     │   IOBuffer      │                 │   IOBuffer      │
+      │   Buffer        │                 │   Buffer        │
-     │ • Base64 encode │                 │ • Upload to     │
+      │ • Base64 encode │                 │ • Upload to     │
-     │ • Publish to    │                 │   HTTP Server   │
+      │ • Publish to    │                 │   HTTP Server   │
-     │   NATS          │                 │ • Publish to    │
+      │   NATS          │                 │ • Publish to    │
-     │                 │                 │   NATS with URL │
+      │                 │                 │   NATS with URL │
-     └─────────────────┘                 └─────────────────┘
+      └─────────────────┘                 └─────────────────┘
 ```
 
 ## Files
 
-### Julia Module: [`src/julia_bridge.jl`](../src/julia_bridge.jl)
+### Julia Module: [`src/NATSBridge.jl`](../src/NATSBridge.jl)
 
 The Julia implementation provides:
 
-- **[`MessageEnvelope`](../src/julia_bridge.jl)**: Struct for the unified JSON envelope
+- **[`MessageEnvelope`](src/NATSBridge.jl)**: Struct for the unified JSON envelope
-- **[`SmartSend()`](../src/julia_bridge.jl)**: Handles transport selection based on payload size
+- **[`SmartSend()`](src/NATSBridge.jl)**: Handles transport selection based on payload size
-- **[`SmartReceive()`](../src/julia_bridge.jl)**: Handles both direct and link transport
+- **[`SmartReceive()`](src/NATSBridge.jl)**: Handles both direct and link transport
 
 ### JavaScript Module: [`src/NATSBridge.js`](../src/NATSBridge.js)
 
@@ -77,8 +162,17 @@ 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
+- **[`smartsend()`](src/NATSBridge.js)**: Handles transport selection based on payload size
-- **[`smartreceive()`](../src/NATSBridge.js)**: Handles both direct and link transport
+- **[`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
 
@@ -100,6 +194,23 @@ Pkg.add("Dates")
 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
@@ -138,34 +249,31 @@ node test/scenario3_julia_to_julia.js
 
 ### Scenario 0: Basic Multi-Payload Example
 
-#### Julia (Sender)
+#### Python/Micropython (Sender)
-```julia
+```python
-using NATSBridge
+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",
+    fileserver_url="http://localhost:8080"
-    metadata=Dict("custom_key" => "custom_value")
 )
 
 # Even single payload must be wrapped in a list with type
 smartsend("/test", [("single_data", mydata, "dictionary")])
 ```
 
-#### Julia (Receiver)
+#### Python/Micropython (Receiver)
-```julia
+```python
-using NATSBridge
+from nats_bridge import smartreceive
 
-# Receive returns a list of payloads with type info
+# Receive returns a list of (dataname, data, type) tuples
-payloads = smartreceive(msg, "http://localhost:8080")
+payloads = smartreceive(msg)
 # payloads = [(dataname1, data1, "dictionary"), (dataname2, data2, "table"), ...]
 ```
 
-### Scenario 1: Command & Control (Small JSON)
-
 #### JavaScript (Sender)
 ```javascript
 const { smartsend } = require('./src/NATSBridge');
@@ -198,27 +306,7 @@ const configs = [
 await smartsend("control", configs);
 ```
 
-#### Julia (Receiver)
+#### JavaScript (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
-```
-
-### JavaScript (Receiver)
 ```javascript
 const { smartreceive } = require('./src/NATSBridge');
 
@@ -227,13 +315,18 @@ const nc = await connect({ servers: ['nats://localhost:4222'] });
 const sub = nc.subscribe("control");
 
 for await (const msg of sub) {
-    const result = await smartreceive(msg);
+    const envelope = await smartreceive(msg);
     
-    // Process the result
+    // Process the payloads from the envelope
-    for (const { dataname, data, type } of result) {
+    for (const payload of envelope.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: ${envelope.correlationId}`);
+    console.log(`Message ID: ${envelope.msgId}`);
 }
 ```
 
@@ -259,15 +352,35 @@ await SmartSend("analysis_results", [("table_data", df, "table")]);
 ```javascript
 const { smartreceive } = require('./src/NATSBridge');
 
-const result = await smartreceive(msg);
+const envelope = await smartreceive(msg);
 
-// Use table data for visualization with Perspective.js or D3
+// Use table data from the payloads field
 // Note: Tables are sent as arrays of objects in JavaScript
-const table = result;
+const table = envelope.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');
@@ -287,35 +400,35 @@ await smartsend("binary_input", binaryData, {
 });
 ```
 
-#### Julia (Receiver)
+#### Python/Micropython (Receiver)
-```julia
+```python
-using WAV
+from nats_bridge import smartreceive
-using DSP
 
 # Receive binary data
-function process_binary(data)
+def process_binary(msg):
-    # Perform FFT or AI transcription
+    envelope = smartreceive(msg)
-    spectrum = fft(data)
     
-    # Send results back (JSON + Arrow table)
+    # Process the binary data from envelope.payloads
-    results = Dict("transcription" => "sample text", "spectrum" => spectrum)
+    for dataname, data, type in envelope["payloads"]:
-    await SmartSend("binary_output", results, "json")
+        if type == "binary":
-end
+            # data is bytes
+            print(f"Received binary data: {dataname}, size: {len(data)}")
+            # Perform FFT or AI transcription here
 ```
 
-### JavaScript (Receiver)
+#### JavaScript (Receiver)
 ```javascript
 const { smartreceive } = require('./src/NATSBridge');
 
 // Receive binary data
 function process_binary(msg) {
-    const result = await smartreceive(msg);
+    const envelope = await smartreceive(msg);
     
-    // Process the binary data
+    // Process the binary data from envelope.payloads
-    for (const { dataname, data, type } of result) {
+    for (const payload of envelope.payloads) {
-        if (type === "binary") {
+        if (payload.type === "binary") {
             // data is an ArrayBuffer or Uint8Array
-            console.log(`Received binary data: ${dataname}, size: ${data.length}`);
+            console.log(`Received binary data: ${payload.dataname}, size: ${payload.data.length}`);
             // Perform FFT or AI transcription here
         }
     }
@@ -353,13 +466,71 @@ const consumer = await js.pullSubscribe("health", {
 
 // Process historical and real-time messages
 for await (const msg of consumer) {
-    const result = await smartreceive(msg);
+    const envelope = await smartreceive(msg);
-    // result contains the list of payloads
+    // envelope.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):
+    envelope = smartreceive(msg)
+    
+    # Process configuration from payloads
+    for dataname, data, type in envelope["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=envelope.get("replyTo")
+    )
+```
+
+**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.
@@ -395,11 +566,11 @@ smartsend(
 const { smartreceive, smartsend } = require('./src/NATSBridge');
 
 // Receive NATS message with direct transport
-const result = await smartreceive(msg);
+const envelope = await smartreceive(msg);
 
 // Decode Base64 payload (for direct transport)
-// For tables, data is an array of objects
+// For tables, data is in envelope.payloads
-const table = result;  // Array of objects
+const table = envelope.payloads;  // Array of objects
 
 // User makes selection
 const selection = uiComponent.getSelectedOption();
@@ -558,7 +729,7 @@ await smartsend("chat.room123", message);
 ### Exponential Backoff
 - Maximum retry count: 5
 - Base delay: 100ms, max delay: 5000ms
-- Implemented in both Julia and JavaScript implementations
+- Implemented in all three implementations (Julia, JavaScript, Python/Micropython)
 
 ### Correlation ID Logging
 - Log correlation_id at every stage
@@ -567,14 +738,73 @@ await smartsend("chat.room123", message);
 
 ## Testing
 
-Run the test scripts:
+Run the test scripts for each platform:
+
+### Python/Micropython Tests
 
 ```bash
-# Scenario 1: Command & Control (JavaScript sender)
+# Basic functionality test
-node test/scenario1_command_control.js
+python test/test_micropython_basic.py
+```
 
-# Scenario 2: Large Arrow Table (JavaScript sender)
+### JavaScript Tests
-node test/scenario2_large_table.js
+
+```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
@@ -582,18 +812,24 @@ node test/scenario2_large_table.js
 ### Common Issues
 
 1. **NATS Connection Failed**
-   - Ensure NATS server is running
+   - **Julia/JavaScript/Python**: Ensure NATS server is running
-   - Check NATS_URL configuration
+   - **Python/Micropython**: Check `nats_url` parameter and network connectivity
 
 2. **HTTP Upload Failed**
    - Ensure file server is running
-   - Check FILESERVER_URL configuration
+   - 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

@@ -1,21 +0,0 @@
-Check architecture.jl, NATSBridge.jl and its test files:
-- test_julia_to_julia_table_receiver.jl
-- test_julia_to_julia_table_sender.jl. 
-
-Now I want to test sending a mix-content message from Julia serviceA to Julia serviceB, for example, a chat system. 
-The test message must show that any combination and any number and any data size of text | json | table | image | audio | video | binary can be send and receive.
-
-Can you write me the following test files:
-- test_julia_to_julia_mix_receiver.jl
-- test_julia_to_julia_mix_sender.jl
-
-
-
-
-1. create a tutorial file "tutorial_julia.md" for NATSBridge.jl
-2. create a walkthrough file "walkthrough_julia.md" for NATSBridge.jl
-
-You may consult architecture.md for more info.
-
-
-

examples/tutorial.md

@@ -0,0 +1,604 @@
+# 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
+data = [("message", "Hello World", "text")]
+env = smartsend("/chat/room1", data, nats_url="nats://localhost:4222")
+print("Message sent!")
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+// Send a text message
+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 = smartsend("/chat/room1", data, nats_url="nats://localhost:4222")
+println("Message sent!")
+```
+
+### Step 4: Receive Messages
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartreceive
+
+# Receive and process message
+envelope = smartreceive(msg)
+for dataname, data, type in envelope["payloads"]:
+    print(f"Received {dataname}: {data}")
+```
+
+#### JavaScript
+
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+
+// Receive and process message
+const envelope = await smartreceive(msg);
+for (const payload of envelope.payloads) {
+    console.log(`Received ${payload.dataname}: ${payload.data}`);
+}
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+# Receive and process message
+envelope = smartreceive(msg, fileserverDownloadHandler)
+for (dataname, data, type) in envelope["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 = 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
+};
+
+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")]
+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 = 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');
+
+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")]
+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 = smartsend(
+    "/device/command",
+    data,
+    nats_url="nats://localhost:4222",
+    reply_to="/device/response",
+    reply_to_msg_id="cmd-001"
+)
+```
+
+#### 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 envelope = await smartreceive(msg);
+    
+    // Process command
+    for (const payload of envelope.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: envelope.replyTo,
+                    reply_to_msg_id: envelope.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 = 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
+
+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 = 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 = smartsend("/chat/mixed", data, nats_url="nats://localhost:4222")
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend } = require('./src/NATSBridge');
+
+const fs = require('fs');
+
+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")
+]
+
+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 = 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")]
+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")]
+smartsend("/analysis/config", data, nats_url="nats://localhost:4222")
+```
+
+#### JavaScript Receiver
+
+```javascript
+const { smartreceive } = require('./src/NATSBridge');
+
+// Receive dictionary from Julia
+const envelope = await smartreceive(msg);
+for (const payload of envelope.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');
+
+await smartsend("/data/transfer", [
+    { dataname: "message", data: "Hello from JS!", type: "text" }
+]);
+```
+
+#### Python Receiver
+
+```python
+from nats_bridge import smartreceive
+
+envelope = smartreceive(msg)
+for dataname, data, type in envelope["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")]
+smartsend("/chat/python", data)
+```
+
+#### Julia Receiver
+
+```julia
+using NATSBridge
+
+envelope = smartreceive(msg, fileserverDownloadHandler)
+for (dataname, data, type) in envelope["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

src/NATSBridge.jl

@@ -10,7 +10,7 @@
 # 
 # Handler Function Signatures:
 #
-# ```julia
+# ```jldoctest
 # # Upload handler - uploads data to file server and returns URL
 # fileserverUploadHandler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
 #
@@ -23,7 +23,7 @@
 # Even when sending a single payload, the user must wrap it in a list.
 # 
 # API Standard:
-# ```julia
+# ```jldoctest
 # # Input format for smartsend (always a list of tuples with type info)
 # [(dataname1, data1, type1), (dataname2, data2, type2), ...]
 # 
@@ -45,6 +45,59 @@ 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
 
 
+""" msgPayload_v1 - Internal message payload structure
+This structure represents a single payload within a NATS message envelope.
+It supports both direct transport (base64-encoded data) and link transport (URL-based).
+
+# Arguments:
+  - `id::String` - Unique identifier for this payload (e.g., "uuid4")
+  - `dataname::String` - Name of the payload (e.g., "login_image")
+  - `type::String` - Payload type: "text", "dictionary", "table", "image", "audio", "video", "binary"
+  - `transport::String` - Transport method: "direct" or "link"
+  - `encoding::String` - Encoding method: "none", "json", "base64", "arrow-ipc"
+  - `size::Integer` - Size of the payload in bytes (e.g., 15433)
+  - `data::Any` - Payload data (bytes for direct, URL for link)
+  - `metadata::Dict{String, Any}` - Optional metadata dictionary
+
+# Keyword Arguments:
+  - `id::String = ""` - Payload ID, auto-generated if empty
+  - `dataname::String = string(uuid4())` - Payload name, auto-generated UUID if empty
+  - `transport::String = "direct"` - Transport method
+  - `encoding::String = "none"` - Encoding method
+  - `size::Integer = 0` - Payload size
+  - `metadata::Dict{String, T} = Dict{String, Any}()` - Metadata dictionary
+
+# Return:
+  - A msgPayload_v1 struct instance
+
+# Example
+```jldoctest
+using UUIDs
+
+# Create a direct transport payload
+payload = msgPayload_v1(
+    "Hello World",
+    "text";
+    id = string(uuid4()),
+    dataname = "message",
+    transport = "direct",
+    encoding = "base64",
+    size = 11,
+    metadata = Dict{String, Any}()
+)
+
+# Create a link transport payload
+payload = msgPayload_v1(
+    "http://example.com/file.zip",
+    "binary";
+    id = string(uuid4()),
+    dataname = "file",
+    transport = "link",
+    encoding = "none",
+    size = 1000000
+)
+```
+"""
 struct msgPayload_v1
   id::String                    # id of this payload e.g. "uuid4"
   dataname::String              # name of this payload e.g. "login_image"
@@ -68,18 +121,63 @@ function msgPayload_v1(
   metadata::Dict{String, T} = Dict{String, Any}()
 ) where {T<:Any}
   return msgPayload_v1(
-            id,
+             id,
-            dataname,
+             dataname,
-            type,
+             type,
-            transport,
+             transport,
-            encoding,
+             encoding,
-            size,
+             size,
-            data,
+             data,
-            metadata
+             metadata
-          )
+           )
 end
 
 
+""" msgEnvelope_v1 - Internal message envelope structure
+This structure represents a complete NATS message envelope containing multiple payloads
+with metadata for routing, tracing, and message context.
+
+# Arguments:
+  - `sendTo::String` - NATS subject/topic to publish the message to (e.g., "/agent/wine/api/v1/prompt")
+  - `payloads::AbstractArray{msgPayload_v1}` - List of payloads to include in the message
+
+# Keyword Arguments:
+  - `correlationId::String = ""` - Unique identifier to track messages across systems; auto-generated if empty
+  - `msgId::String = ""` - Unique message identifier; auto-generated if empty
+  - `timestamp::String = string(Dates.now())` - Message publication timestamp
+  - `msgPurpose::String = ""` - Purpose of the message: "ACK", "NACK", "updateStatus", "shutdown", "chat", etc.
+  - `senderName::String = ""` - Name of the sender (e.g., "agent-wine-web-frontend")
+  - `senderId::String = ""` - UUID of the sender; auto-generated if empty
+  - `receiverName::String = ""` - Name of the receiver (empty string means broadcast)
+  - `receiverId::String = ""` - UUID of the receiver (empty string means broadcast)
+  - `replyTo::String = ""` - Topic where receiver should reply (empty string if no reply expected)
+  - `replyToMsgId::String = ""` - Message ID this message is replying to
+  - `brokerURL::String = DEFAULT_NATS_URL` - NATS broker URL
+  - `metadata::Dict{String, Any} = Dict{String, Any}()` - Optional message-level metadata
+
+# Return:
+  - A msgEnvelope_v1 struct instance
+
+# Example
+```jldoctest
+using UUIDs, NATSBridge
+
+# Create payloads for the message
+payload1 = msgPayload_v1("Hello", "text"; dataname="message", transport="direct", encoding="base64")
+payload2 = msgPayload_v1("http://example.com/file.zip", "binary"; dataname="file", transport="link")
+
+# Create message envelope
+env = msgEnvelope_v1(
+    "my.subject",
+    [payload1, payload2];
+    correlationId = string(uuid4()),
+    msgPurpose = "chat",
+    senderName = "my-app",
+    receiverName = "receiver-app",
+    replyTo = "reply.subject"
+)
+```
+"""
 struct msgEnvelope_v1
   correlationId::String       # Unique identifier to track messages across systems. Many senders can talk about the same topic.
   msgId::String               # this message id
@@ -137,8 +235,34 @@ end
 
 
 
-""" Convert msgEnvelope_v1 to JSON string
+""" envelope_to_json - Convert msgEnvelope_v1 to JSON string
-This function converts the msgEnvelope_v1 struct to a JSON string representation.
+This function converts the msgEnvelope_v1 struct to a JSON string representation,
+preserving all metadata and payload information for NATS message publishing.
+
+# Function Workflow:
+1. Creates a dictionary with envelope metadata (correlationId, msgId, timestamp, etc.)
+2. Conditionally includes metadata dictionary if not empty
+3. Iterates through payloads and converts each to JSON-compatible dictionary
+4. Handles direct transport payloads (Base64 encoding) and link transport payloads (URL)
+5. Returns final JSON string representation
+
+# Arguments:
+  - `env::msgEnvelope_v1` - The msgEnvelope_v1 struct to convert to JSON
+
+# Return:
+  - `String` - JSON string representation of the envelope
+
+# Example
+```jldoctest
+using UUIDs
+
+# Create an envelope with payloads
+payload = msgPayload_v1("Hello", "text"; dataname="msg", transport="direct", encoding="base64")
+env = msgEnvelope_v1("my.subject", [payload])
+
+# Convert to JSON for publishing
+json_msg = envelope_to_json(env)
+```
 """
 function envelope_to_json(env::msgEnvelope_v1)
   obj = Dict{String, Any}(
@@ -197,9 +321,24 @@ function envelope_to_json(env::msgEnvelope_v1)
 end
 
 
-""" Log a trace message with correlation ID and timestamp
+""" log_trace - Log a trace message with correlation ID and timestamp
 This function logs information messages with a correlation ID for tracing purposes,
 making it easier to track message flow across distributed systems.
+
+# Arguments:
+  - `correlation_id::String` - Correlation ID to identify the message flow
+  - `message::String` - The message content to log
+
+# Return:
+  - `nothing` - This function performs logging but returns nothing
+
+# Example
+```jldoctest
+using Dates
+
+log_trace("abc123", "Starting message processing")
+# Logs: [2026-02-21T05:39:00] [Correlation: abc123] Starting message processing
+```
 """
 function log_trace(correlation_id::String, message::String)
     timestamp = Dates.now()  # Get current timestamp
@@ -216,7 +355,7 @@ Otherwise, it uploads the data to a fileserver (by default using `plik_oneshot_u
 The function accepts a list of (dataname, data, type) tuples as input and processes each payload individually.
 Each payload can have a different type, enabling mixed-content messages (e.g., chat with text, images, audio).
 
-The function workflow:
+# Function Workflow:
 1. Iterates through the list of (dataname, data, type) tuples
 2. For each payload: extracts the type from the tuple and serializes accordingly
 3. Compares the serialized size against `size_threshold`
@@ -247,7 +386,7 @@ The function workflow:
   - A `msgEnvelope_v1` object containing metadata and transport information
 
 # Example
-```julia
+```jldoctest
 using UUIDs
 
 # Send a single payload (still wrapped in a list)
@@ -376,26 +515,20 @@ end
 
 
 """ _serialize_data - Serialize data according to specified format
-
 This function serializes arbitrary Julia data into a binary representation based on the specified format.
-It supports multiple serialization formats:
+It supports multiple serialization formats for different data types.
-- `"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) and returns the byte stream
-- `"image"`: Expects binary image data (Vector{UInt8}) and returns it as bytes
-- `"audio"`: Expects binary audio data (Vector{UInt8}) and returns it as bytes
-- `"video"`: Expects binary video data (Vector{UInt8}) and returns it as bytes
-- `"binary"`: Generic binary data (Vector{UInt8} or IOBuffer) and returns bytes
 
-The function handles format-specific serialization logic:
+# Function Workflow:
-1. For `"text"`: Converts string to UTF-8 bytes
+1. Validates the data type against the specified format
-2. For `"dictionary"`: Converts Julia data to JSON string, then encodes to bytes
+2. Converts data to binary representation according to format rules
-3. For `"table"`: Uses Arrow.jl to write data as an Arrow IPC stream to an in-memory buffer
+3. For text: converts string to UTF-8 bytes
-4. For `"image"`, `"audio"`, `"video"`: Treats data as binary (Vector{UInt8})
+4. For dictionary: serializes as JSON then converts to bytes
-5. For `"binary"`: Extracts bytes from `IOBuffer` or returns `Vector{UInt8}` directly
+5. For table: uses Arrow.jl to write as IPC stream
+6. For image/audio/video/binary: returns binary data directly
 
 # Arguments:
   - `data::Any` - Data to serialize (string for `"text"`, JSON-serializable for `"dictionary"`, table-like for `"table"`, binary for `"image"`, `"audio"`, `"video"`, `"binary"`)
+  - `type::String` - Target format: "text", "dictionary", "table", "image", "audio", "video", "binary"
 
 # Return:
   - `Vector{UInt8}` - Binary representation of the serialized data
@@ -405,7 +538,7 @@ The function handles format-specific serialization logic:
   - `Error` if `type` is `"image"`, `"audio"`, or `"video"` but `data` is not `Vector{UInt8}`
 
 # Example
-```julia
+```jldoctest
 using JSON, Arrow, DataFrames
 
 # Text serialization
@@ -505,15 +638,29 @@ function _serialize_data(data::Any, type::String)
 end
 
 
-""" Publish message to NATS
+""" publish_message - Publish message to NATS
 This internal function publishes a message to a NATS subject with proper
 connection management and logging.
 
-Arguments:
+# Arguments:
-  - `nats_url::String` - NATS server URL
+  - `nats_url::String` - NATS server URL (e.g., "nats://localhost:4222")
-  - `subject::String` - NATS subject to publish to
+  - `subject::String` - NATS subject to publish to (e.g., "/agent/wine/api/v1/prompt")
   - `message::String` - JSON message to publish
-  - `correlation_id::String` - Correlation ID for logging
+  - `correlation_id::String` - Correlation ID for tracing and logging
+
+# Return:
+  - `nothing` - This function performs publishing but returns nothing
+
+# Example
+```jldoctest
+using NATS
+
+# Prepare JSON message
+message = "{\"correlationId\":\"abc123\",\"payload\":\"test\"}"
+
+# Publish to NATS
+publish_message("nats://localhost:4222", "my.subject", message, "abc123")
+```
 """
 function publish_message(nats_url::String, subject::String, message::String, correlation_id::String)
     conn = NATS.connect(nats_url)  # Create NATS connection
@@ -532,20 +679,27 @@ This function processes incoming NATS messages, handling both direct transport
 It deserializes the data based on the transport type and returns the result.
 A HTTP file server is required along with its download function.
 
-Arguments:
+# Function Workflow:
+1. Parses the JSON envelope from the NATS message
+2. Iterates through each payload in the envelope
+3. For each payload: determines the transport type (direct or link)
+4. For direct transport: decodes Base64 payload and deserializes based on type
+5. For link transport: fetches data from URL with exponential backoff, then deserializes
+
+# Arguments:
   - `msg::NATS.Msg` - NATS message to process
-  - `fileserverDownloadHandler::Function` - Function to handle downloading data from file server URLs
 
-Keyword Arguments:
+# Keyword Arguments:
-  - `max_retries::Int` - Maximum retry attempts for fetching URL (default: 5)
+  - `fileserverDownloadHandler::Function = _fetch_with_backoff` - Function to handle downloading data from file server URLs
-  - `base_delay::Int` - Initial delay for exponential backoff in ms (default: 100)
+  - `max_retries::Int = 5` - Maximum retry attempts for fetching URL
-  - `max_delay::Int` - Maximum delay for exponential backoff in ms (default: 5000)
+  - `base_delay::Int = 100` - Initial delay for exponential backoff in ms
+  - `max_delay::Int = 5000` - Maximum delay for exponential backoff in ms
 
-Return:
+# Return:
   - `AbstractArray{Tuple{String, Any, String}}` - List of (dataname, data, type) tuples
 
 # Example
-```julia
+```jldoctest
 # Receive and process message
 msg = nats_message  # NATS message
 payloads = smartreceive(msg; fileserverDownloadHandler=_fetch_with_backoff, max_retries=5, base_delay=100, max_delay=5000)
@@ -605,24 +759,40 @@ function smartreceive(
             error("Unknown transport type for payload '$dataname': $(transport)")  # Throw error for unknown transport
         end
     end
-    
+    json_data["payloads"] = payloads_list
-    return payloads_list  # Return list of (dataname, data, data_type) tuples
+    return json_data  # Return envelope with list of (dataname, data, data_type) tuples in payloads field
 end
 
 
-""" Fetch data from URL with exponential backoff
+""" _fetch_with_backoff - Fetch data from URL with exponential backoff
 This internal function retrieves data from a URL with retry logic using
 exponential backoff to handle transient failures.
 
-Arguments:
+# Function Workflow:
+1. Initializes delay with base_delay value
+2. Attempts to fetch data from URL in a retry loop
+3. On success: logs success and returns response body as bytes
+4. On failure: sleeps using exponential backoff and retries
+5. After max_retries: throws error indicating failure
+
+# Arguments:
   - `url::String` - URL to fetch from
   - `max_retries::Int` - Maximum number of retry attempts
   - `base_delay::Int` - Initial delay in milliseconds
   - `max_delay::Int` - Maximum delay in milliseconds
   - `correlation_id::String` - Correlation ID for logging
 
-Return:
+# Return:
-  - Vector{UInt8} - Fetched data as bytes
+  - `Vector{UInt8}` - Fetched data as bytes
+
+# Throws:
+  - `Error` if all retry attempts fail
+
+# Example
+```jldoctest
+# Fetch data with exponential backoff
+data = _fetch_with_backoff("http://example.com/file.zip", 5, 100, 5000, "correlation123")
+```
 """
 function _fetch_with_backoff(
     url::String,
@@ -655,18 +825,44 @@ function _fetch_with_backoff(
 end
 
 
-""" Deserialize bytes to data based on type
+""" _deserialize_data - Deserialize bytes to data based on type
 This internal function converts serialized bytes back to Julia data based on type.
 It handles "text" (string), "dictionary" (JSON deserialization), "table" (Arrow IPC deserialization),
 "image" (binary data), "audio" (binary data), "video" (binary data), and "binary" (binary data).
 
-Arguments:
+# Function Workflow:
+1. Validates the data type against supported formats
+2. Converts bytes to appropriate Julia data type based on format
+3. For text: converts bytes to string
+4. For dictionary: converts bytes to JSON string then parses to Julia object
+5. For table: reads Arrow IPC format and returns DataFrame
+6. For image/audio/video/binary: returns bytes directly
+
+# Arguments:
   - `data::Vector{UInt8}` - Serialized data as bytes
   - `type::String` - Data type ("text", "dictionary", "table", "image", "audio", "video", "binary")
   - `correlation_id::String` - Correlation ID for logging
 
-Return:
+# Return:
   - Deserialized data (String for "text", DataFrame for "table", JSON data for "dictionary", bytes for "image", "audio", "video", "binary")
+
+# Throws:
+  - `Error` if `type` is not one of the supported types
+
+# Example
+```jldoctest
+# Text data
+text_bytes = UInt8["Hello World"]
+text_data = _deserialize_data(text_bytes, "text", "correlation123")
+
+# JSON data
+json_bytes = UInt8[123, 34, 110, 97, 109, 101, 34, 58, 34, 65, 108, 105, 99, 101, 125]  # {"name":"Alice"}
+json_data = _deserialize_data(json_bytes, "dictionary", "correlation123")
+
+# Arrow IPC data (table)
+arrow_bytes = UInt8[1, 2, 3]  # Arrow IPC bytes
+table_data = _deserialize_data(arrow_bytes, "table", "correlation123")
+```
 """
 function _deserialize_data(
     data::Vector{UInt8},
@@ -697,15 +893,15 @@ end
 
 
 """ 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 workflow:
+# Function Workflow:
-1. Obtains an upload ID and token from the server
+1. Creates a one-shot upload session by sending POST request with `{"OneShot": true}`
-2. Uploads the provided binary data as a file using the `X-UploadToken` header
+2. Retrieves upload ID and token from server response
-3. Returns identifiers and download URL for the uploaded file
+3. Uploads binary data as multipart form data using the token
+4. Returns identifiers and download URL for the uploaded file
 
 # Arguments:
   - `fileServerURL::String` - Base URL of the plik server (e.g., `"http://localhost:8080"`)
@@ -713,14 +909,14 @@ The function workflow:
   - `data::Vector{UInt8}` - Raw byte data of the file content
 
 # Return:
-  - A Dict with keys:
+  - `Dict{String, Any}` - 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
 
 # Example
-```julia
+```jldoctest
 using HTTP, JSON
 
 fileServerURL = "http://localhost:8080"
@@ -776,31 +972,29 @@ end
 
 
 """ plik_oneshot_upload(fileServerURL::String, filepath::String)
-
-Upload a single file to a plik server using one-shot mode.
-
 This function uploads a file from disk 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 workflow:
+# Function Workflow:
-1. Obtains an upload ID and token from the server
+1. Creates a one-shot upload session by sending POST request with `{"OneShot": true}`
-2. Uploads the file at `filepath` using multipart form data and the `X-UploadToken` header
+2. Retrieves upload ID and token from server response
-3. Returns identifiers and download URL for the uploaded file
+3. Uploads the file at `filepath` using multipart form data and the `X-UploadToken` header
+4. Returns identifiers and download URL for the uploaded file
 
 # Arguments:
   - `fileServerURL::String` - Base URL of the plik server (e.g., `"http://localhost:8080"`)
   - `filepath::String` - Full path to the local file to upload
 
 # Return:
-  - A Dict with keys:
+  - `Dict{String, Any}` - 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
 
 # Example
-```julia
+```jldoctest
 using HTTP, JSON
 
 fileServerURL = "http://localhost:8080"

src/NATSBridge.js

@@ -603,7 +603,7 @@ async function smartreceive(msg, options = {}) {
      * @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<Array>} - List of {dataname, data, type} objects
+     * @returns {Promise<Object>} - Envelope dictionary with metadata and payloads field containing list of {dataname, data, type} objects
      */
     const {
         fileserverDownloadHandler = _fetch_with_backoff,
@@ -664,7 +664,10 @@ async function smartreceive(msg, options = {}) {
         }
     }
     
-    return payloads_list;
+    // Replace payloads array with the processed list of {dataname, data, type} tuples
+    json_data.payloads = payloads_list;
+    
+    return json_data;
 }
 
 // Export for Node.js

src/README.md

@@ -0,0 +1,295 @@
+# NATSBridge
+
+A high-performance, bi-directional data bridge for **Julia**, **JavaScript**, and **Python/Micropython** using NATS (Core & JetStream), implementing the Claim-Check pattern for large payloads.
+
+## 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
+
+## Features
+
+- ✅ Bi-directional NATS communication across Julia ↔ JavaScript ↔ Python/Micropython
+- ✅ Multi-payload support (mixed content in single message)
+- ✅ Automatic transport selection based on payload size
+- ✅ File server integration for large payloads
+- ✅ Exponential backoff for URL fetching
+- ✅ Correlation ID tracking
+- ✅ Reply-to support for request-response pattern
+
+## 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 |
+
+## Implementation Guides
+
+### [Julia Implementation](../tutorial_julia.md)
+
+See the [Julia tutorial](../tutorial_julia.md) for getting started with Julia.
+
+### [JavaScript Implementation](#javascript-implementation)
+
+See [`NATSBridge.js`](NATSBridge.js) for the JavaScript implementation.
+
+### [Python/Micropython Implementation](#pythonmicropython-implementation)
+
+See [`nats_bridge.py`](nats_bridge.py) for the Python/Micropython implementation.
+
+## 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 `nats_bridge.py` to your device
+2. Ensure you have the following dependencies:
+   - `urequests` for HTTP requests (Micropython)
+   - `requests` for HTTP requests (Python)
+   - `base64` for base64 encoding
+   - `json` for JSON handling
+   - `socket` for networking (Micropython)
+
+## Usage
+
+### Basic Text Message
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend, smartreceive
+
+# Sender
+data = [("message", "Hello World", "text")]
+env = smartsend("/chat/room1", data, nats_url="nats://localhost:4222")
+
+# Receiver
+payloads = smartreceive(msg)
+for dataname, data, type in payloads:
+    print("Received {}: {}".format(dataname, data))
+```
+
+#### Julia
+
+```julia
+using NATSBridge
+
+# Sender
+data = [("message", "Hello World", "text")]
+env = smartsend("/chat/room1", data, nats_url="nats://localhost:4222")
+
+# Receiver
+envelope = smartreceive(msg, fileserverDownloadHandler)
+# envelope["payloads"] = [("message", "Hello World", "text"), ...]
+```
+
+#### JavaScript
+
+```javascript
+const { smartsend, smartreceive } = require('./src/NATSBridge');
+
+// Sender
+await smartsend("/chat/room1", [
+    { dataname: "message", data: "Hello World", type: "text" }
+], { natsUrl: "nats://localhost:4222" });
+
+// Receiver
+const envelope = await smartreceive(msg);
+// envelope.payloads = [{ dataname: "message", data: "Hello World", type: "text" }, ...]
+```
+
+### Sending JSON Configuration
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+config = {
+    "wifi_ssid": "MyNetwork",
+    "wifi_password": "password123",
+    "update_interval": 60
+}
+
+data = [("config", config, "dictionary")]
+env = smartsend("/device/config", data, nats_url="nats://localhost:4222")
+```
+
+### Mixed Content (Chat with Text + Image)
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+image_data = b"\x89PNG..."  # PNG bytes
+
+data = [
+    ("message_text", "Hello with image!", "text"),
+    ("user_avatar", image_data, "binary")
+]
+
+env = smartsend("/chat/mixed", data, nats_url="nats://localhost:4222")
+```
+
+### Request-Response Pattern
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+# Send command with reply-to
+data = [("command", {"action": "read_sensor"}, "dictionary")]
+env = smartsend(
+    "/device/command",
+    data,
+    nats_url="nats://localhost:4222",
+    reply_to="/device/response",
+    reply_to_msg_id="cmd-001"
+)
+```
+
+### Large Payloads (File Server)
+
+#### Python/Micropython
+
+```python
+from nats_bridge import smartsend
+
+# Large data (> 1MB)
+large_data = b"A" * 2000000  # 2MB
+
+env = smartsend(
+    "/data/large",
+    [("large_file", large_data, "binary")],
+    nats_url="nats://localhost:4222",
+    fileserver_url="http://localhost:8080",
+    size_threshold=1000000  # 1MB threshold
+)
+```
+
+## API Reference
+
+### `smartsend(subject, data, ...)`
+
+Send data via NATS with automatic transport selection.
+
+**Arguments:**
+- `subject` (str): NATS subject to publish to
+- `data` (list): List of `(dataname, data, type)` tuples
+- `nats_url` (str): NATS server URL (default: `nats://localhost:4222`)
+- `fileserver_url` (str): HTTP file server URL (default: `http://localhost:8080`)
+- `size_threshold` (int): Threshold in bytes (default: 1,000,000)
+- `correlation_id` (str): Optional correlation ID for tracing
+- `msg_purpose` (str): Message purpose (default: `"chat"`)
+- `sender_name` (str): Sender name (default: `"NATSBridge"`)
+- `receiver_name` (str): Receiver name (default: `""`)
+- `receiver_id` (str): Receiver ID (default: `""`)
+- `reply_to` (str): Reply topic (default: `""`)
+- `reply_to_msg_id` (str): Reply message ID (default: `""`)
+
+**Returns:** `MessageEnvelope` object
+
+### `smartreceive(msg, ...)`
+
+Receive and process NATS messages.
+
+**Arguments:**
+- `msg`: NATS message (dict or JSON string)
+- `fileserver_download_handler` (function): Function to fetch data from URLs
+- `max_retries` (int): Maximum retry attempts (default: 5)
+- `base_delay` (int): Initial delay in ms (default: 100)
+- `max_delay` (int): Maximum delay in ms (default: 5000)
+
+**Returns:** List of `(dataname, data, type)` tuples
+
+### `MessageEnvelope`
+
+Represents a complete NATS message envelope.
+
+**Attributes:**
+- `correlation_id`: Unique identifier for tracing
+- `msg_id`: Unique message identifier
+- `timestamp`: Message publication timestamp
+- `send_to`: NATS subject
+- `msg_purpose`: Message purpose
+- `sender_name`: Sender name
+- `sender_id`: Sender UUID
+- `receiver_name`: Receiver name
+- `receiver_id`: Receiver UUID
+- `reply_to`: Reply topic
+- `reply_to_msg_id`: Reply message ID
+- `broker_url`: NATS broker URL
+- `metadata`: Message-level metadata
+- `payloads`: List of MessagePayload objects
+
+### `MessagePayload`
+
+Represents a single payload within a message envelope.
+
+**Attributes:**
+- `id`: Unique payload identifier
+- `dataname`: Name of the payload
+- `type`: Payload type ("text", "dictionary", etc.)
+- `transport`: Transport method ("direct" or "link")
+- `encoding`: Encoding method ("none", "base64", etc.)
+- `size`: Payload size in bytes
+- `data`: Payload data (bytes for direct, URL for link)
+- `metadata`: Payload-level metadata
+
+## Examples
+
+See [`examples/micropython_example.py`](../examples/micropython_example.py) for more detailed examples.
+
+## Testing
+
+Run the test suite:
+
+```bash
+# Python/Micropython
+python test/test_micropython_basic.py
+
+# JavaScript
+node test/test_js_to_js_text_sender.js
+node test/test_js_to_js_text_receiver.js
+
+# Julia
+julia test/test_julia_to_julia_text_sender.jl
+julia test/test_julia_to_julia_text_receiver.jl
+```
+
+## Requirements
+
+- **Julia**: NATS server (nats.io), HTTP file server (optional)
+- **JavaScript**: NATS server (nats.io), HTTP file server (optional)
+- **Python/Micropython**: NATS server (nats.io), HTTP file server (optional)
+
+## License
+
+MIT

src/nats_bridge.py

@@ -0,0 +1,667 @@
+"""
+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=""):
+    """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
+    
+    Returns:
+        MessageEnvelope: The envelope object for tracking
+    """
+    # 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
+    nats_conn = NATSConnection(nats_url)
+    nats_conn.connect()
+    nats_conn.publish(subject, msg_json)
+    nats_conn.close()
+    
+    return env
+
+
+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/test_js_dict_receiver.js

@@ -37,8 +37,9 @@ async function test_dict_receive() {
             }
         );
         
-        // Result is a list of {dataname, data, type} objects
+        // Result is an envelope dictionary with payloads field
-        for (const { dataname, data, type } of result) {
+        // 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}`);
                 

test/test_js_file_receiver.js

@@ -36,8 +36,9 @@ async function test_large_binary_receive() {
             }
         );
         
-        // Result is a list of {dataname, data, type} objects
+        // Result is an envelope dictionary with payloads field
-        for (const { dataname, data, type } of result) {
+        // 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}`);

test/test_js_mix_payloads_receiver.js

@@ -40,10 +40,11 @@ async function test_mix_receive() {
             }
         );
         
-        log_trace(`Received ${result.length} payloads`);
+        log_trace(`Received ${result.payloads.length} payloads`);
         
-        // Result is a list of {dataname, data, type} objects
+        // Result is an envelope dictionary with payloads field
-        for (const { dataname, data, type } of result) {
+        // Access payloads with result.payloads
+        for (const { dataname, data, type } of result.payloads) {
             log_trace(`\n=== Payload: ${dataname} (type: ${type}) ===`);
             
             // Handle different data types
@@ -122,13 +123,13 @@ async function test_mix_receive() {
         
         // Summary
         console.log("\n=== Verification Summary ===");
-        const text_count = result.filter(x => x.type === "text").length;
+        const text_count = result.payloads.filter(x => x.type === "text").length;
-        const dict_count = result.filter(x => x.type === "dictionary").length;
+        const dict_count = result.payloads.filter(x => x.type === "dictionary").length;
-        const table_count = result.filter(x => x.type === "table").length;
+        const table_count = result.payloads.filter(x => x.type === "table").length;
-        const image_count = result.filter(x => x.type === "image").length;
+        const image_count = result.payloads.filter(x => x.type === "image").length;
-        const audio_count = result.filter(x => x.type === "audio").length;
+        const audio_count = result.payloads.filter(x => x.type === "audio").length;
-        const video_count = result.filter(x => x.type === "video").length;
+        const video_count = result.payloads.filter(x => x.type === "video").length;
-        const binary_count = result.filter(x => x.type === "binary").length;
+        const binary_count = result.payloads.filter(x => x.type === "binary").length;
         
         log_trace(`Text payloads: ${text_count}`);
         log_trace(`Dictionary payloads: ${dict_count}`);
@@ -140,7 +141,7 @@ async function test_mix_receive() {
         
         // Print transport type info for each payload if available
         console.log("\n=== Payload Details ===");
-        for (const { dataname, data, type } of result) {
+        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") {

test/test_js_table_receiver.js

@@ -40,8 +40,9 @@ async function test_table_receive() {
             }
         );
         
-        // Result is a list of {dataname, data, type} objects
+        // Result is an envelope dictionary with payloads field
-        for (const { dataname, data, type } of result) {
+        // 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}`);
                 

test/test_js_text_receiver.js

@@ -37,8 +37,9 @@ async function test_text_receive() {
             }
         );
         
-        // Result is a list of {dataname, data, type} objects
+        // Result is an envelope dictionary with payloads field
-        for (const { dataname, data, type } of result) {
+        // 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`);

test/test_julia_dict_receiver.jl

@@ -42,8 +42,8 @@ function test_dict_receive()
             max_delay = 5000
         )
         
-        # Result is a list of (dataname, data, data_type) tuples
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
-        for (dataname, data, data_type) in result
+        for (dataname, data, data_type) in result["payloads"]
             if isa(data, JSON.Object{String, Any})
                 log_trace("Received Dictionary '$dataname' of type $data_type")
                 

test/test_julia_dict_sender.jl

@@ -94,7 +94,7 @@ function test_dict_send()
     # For large Dictionary: will use link transport (uploaded to fileserver)
     env = NATSBridge.smartsend(
         SUBJECT,
-        [data1, data2],  # List of (dataname, data, type) tuples
+        [data1, data2];  # List of (dataname, data, type) tuples
         nats_url = NATS_URL,
         fileserver_url = FILESERVER_URL,
         fileserverUploadHandler = plik_upload_handler,

test/test_julia_file_receiver.jl

@@ -44,8 +44,8 @@ function test_large_binary_receive()
             max_delay = 5000
         )
         
-        # Result is a list of (dataname, data) tuples
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
-        for (dataname, data, data_type) in result
+        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

test/test_julia_file_sender.jl

@@ -81,7 +81,7 @@ function test_large_binary_send()
     # API: smartsend(subject, [(dataname, data, type), ...]; keywords...)
     env = NATSBridge.smartsend(
         SUBJECT,
-        [data1, data2],  # List of (dataname, data, type) tuples
+        [data1, data2];  # List of (dataname, data, type) tuples
         nats_url = NATS_URL;
         fileserver_url = FILESERVER_URL,
         fileserverUploadHandler = plik_upload_handler,

test/test_julia_mix_payloads_receiver.jl

@@ -45,10 +45,10 @@ function test_mix_receive()
             max_delay = 5000
         )
         
-        log_trace("Received $(length(result)) payloads")
+        log_trace("Received $(length(result["payloads"])) payloads")
         
-        # Result is a list of (dataname, data, data_type) tuples
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
-        for (dataname, data, data_type) in result
+        for (dataname, data, data_type) in result["payloads"]
             log_trace("\n=== Payload: $dataname (type: $data_type) ===")
             
             # Handle different data types
@@ -178,13 +178,13 @@ function test_mix_receive()
         
         # Summary
         println("\n=== Verification Summary ===")
-        text_count = count(x -> x[3] == "text", result)
+        text_count = count(x -> x[3] == "text", result["payloads"])
-        dict_count = count(x -> x[3] == "dictionary", result)
+        dict_count = count(x -> x[3] == "dictionary", result["payloads"])
-        table_count = count(x -> x[3] == "table", result)
+        table_count = count(x -> x[3] == "table", result["payloads"])
-        image_count = count(x -> x[3] == "image", result)
+        image_count = count(x -> x[3] == "image", result["payloads"])
-        audio_count = count(x -> x[3] == "audio", result)
+        audio_count = count(x -> x[3] == "audio", result["payloads"])
-        video_count = count(x -> x[3] == "video", result)
+        video_count = count(x -> x[3] == "video", result["payloads"])
-        binary_count = count(x -> x[3] == "binary", result)
+        binary_count = count(x -> x[3] == "binary", result["payloads"])
         
         log_trace("Text payloads: $text_count")
         log_trace("Dictionary payloads: $dict_count")
@@ -196,7 +196,7 @@ function test_mix_receive()
         
         # Print transport type info for each payload if available
         println("\n=== Payload Details ===")
-        for (dataname, data, data_type) in result
+        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"

test/test_julia_mix_payloads_sender.jl

@@ -188,7 +188,7 @@ function test_mix_send()
     # Use smartsend with mixed content
     env = NATSBridge.smartsend(
         SUBJECT,
-        payloads,  # List of (dataname, data, type) tuples
+        payloads;  # List of (dataname, data, type) tuples
         nats_url = NATS_URL,
         fileserver_url = FILESERVER_URL,
         fileserverUploadHandler = plik_upload_handler,

test/test_julia_table_receiver.jl

@@ -42,8 +42,8 @@ function test_table_receive()
             max_delay = 5000
         )
         
-        # Result is a list of (dataname, data, data_type) tuples
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
-        for (dataname, data, data_type) in result
+        for (dataname, data, data_type) in result["payloads"]
           data = DataFrame(data)
             if isa(data, DataFrame)
                 log_trace("Received DataFrame '$dataname' of type $data_type")

test/test_julia_table_sender.jl

@@ -92,7 +92,7 @@ function test_table_send()
     # For large DataFrame: will use link transport (uploaded to fileserver)
     env = NATSBridge.smartsend(
         SUBJECT,
-        [data1, data2],  # List of (dataname, data, type) tuples
+        [data1, data2];  # List of (dataname, data, type) tuples
         nats_url = NATS_URL,
         fileserver_url = FILESERVER_URL,
         fileserverUploadHandler = plik_upload_handler,

test/test_julia_text_receiver.jl

@@ -42,8 +42,8 @@ function test_text_receive()
             max_delay = 5000
         )
         
-        # Result is a list of (dataname, data, data_type) tuples
+        # Result is an envelope dictionary with payloads field containing list of (dataname, data, data_type) tuples
-        for (dataname, data, data_type) in result
+        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")

test/test_julia_text_sender.jl

@@ -77,7 +77,7 @@ function test_text_send()
     # For large text: will use link transport (uploaded to fileserver)
     env = NATSBridge.smartsend(
         SUBJECT,
-        [data1, data2],  # List of (dataname, data, type) tuples
+        [data1, data2];  # List of (dataname, data, type) tuples
         nats_url = NATS_URL,
         fileserver_url = FILESERVER_URL,
         fileserverUploadHandler = plik_upload_handler,

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 +1,99 @@
+#!/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 = 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=""
+    )
+    
+    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 +1,79 @@
+#!/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 = 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=""
+    )
+    
+    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 +1,93 @@
+#!/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 = 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=""
+    )
+    
+    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 +1,81 @@
+#!/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 = 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=""
+    )
+    
+    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()

tutorial_julia.md

@@ -1,634 +0,0 @@
-# NATSBridge.jl Tutorial
-
-A comprehensive tutorial for learning how to use NATSBridge.jl for bi-directional communication between Julia and JavaScript services using NATS.
-
-## Table of Contents
-
-1. [What is NATSBridge.jl?](#what-is-natsbridgejl)
-2. [Key Concepts](#key-concepts)
-3. [Installation](#installation)
-4. [Basic Usage](#basic-usage)
-5. [Payload Types](#payload-types)
-6. [Transport Strategies](#transport-strategies)
-7. [Advanced Features](#advanced-features)
-8. [Complete Examples](#complete-examples)
-
----
-
-## What is NATSBridge.jl?
-
-NATSBridge.jl is a Julia module that provides a high-level API for sending and receiving data across network boundaries using NATS as the message bus. It implements the **Claim-Check pattern** for handling large payloads efficiently.
-
-### Core Features
-
-- **Bi-directional communication**: Julia ↔ JavaScript
-- **Smart transport selection**: Automatic direct vs link transport based on payload size
-- **Multi-payload support**: Send multiple payloads of different types in a single message
-- **Claim-check pattern**: Upload large files to HTTP server, send only URLs via NATS
-- **Type-aware serialization**: Different serialization strategies for different data types
-
----
-
-## Key Concepts
-
-### 1. msgEnvelope_v1 (Message Envelope)
-
-The `msgEnvelope_v1` structure provides a comprehensive message format for bidirectional communication:
-
-```julia
-struct msgEnvelope_v1
-  correlationId::String       # Unique identifier to track messages
-  msgId::String               # This message id
-  timestamp::String           # Message published timestamp
-  
-  sendTo::String              # Topic/subject the sender sends to
-  msgPurpose::String          # Purpose (ACK | NACK | updateStatus | shutdown | chat)
-  senderName::String          # Sender name (e.g., "agent-wine-web-frontend")
-  senderId::String            # Sender id (uuid4)
-  receiverName::String        # Message receiver name (e.g., "agent-backend")
-  receiverId::String          # Message receiver id (uuid4 or nothing for broadcast)
-  replyTo::String             # Topic to reply to
-  replyToMsgId::String        # Message id this message is replying to
-  brokerURL::String           # NATS server address
-  
-  metadata::Dict{String, Any}
-  payloads::AbstractArray{msgPayload_v1}  # Multiple payloads stored here
-end
-```
-
-### 2. msgPayload_v1 (Payload Structure)
-
-The `msgPayload_v1` structure provides flexible payload handling:
-
-```julia
-struct msgPayload_v1
-  id::String                    # Id of this payload (e.g., "uuid4")
-  dataname::String              # Name of this payload (e.g., "login_image")
-  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
-```
-
-### 3. Standard API Format
-
-The system uses a **standardized list-of-tuples format** for all payload operations:
-
-```julia
-# Input format for smartsend (always a list of tuples with type info)
-[(dataname1, data1, type1), (dataname2, data2, type2), ...]
-
-# Output format for smartreceive (always returns a list of tuples)
-[(dataname1, data1, type1), (dataname2, data2, type2), ...]
-```
-
-**Important**: Even when sending a single payload, you must wrap it in a list.
-
----
-
-## Installation
-
-```julia
-using Pkg
-Pkg.add("NATS")
-Pkg.add("JSON")
-Pkg.add("Arrow")
-Pkg.add("HTTP")
-Pkg.add("UUIDs")
-Pkg.add("Dates")
-Pkg.add("Base64")
-Pkg.add("PrettyPrinting")
-Pkg.add("DataFrames")
-```
-
-Then include the NATSBridge module:
-
-```julia
-include("NATSBridge.jl")
-using .NATSBridge
-```
-
----
-
-## Basic Usage
-
-### Sending Data (smartsend)
-
-```julia
-using NATSBridge
-
-# Send a simple dictionary
-data = Dict("key" => "value")
-env = NATSBridge.smartsend("my.subject", [("dataname1", data, "dictionary")])
-```
-
-### Receiving Data (smartreceive)
-
-```julia
-using NATSBridge
-
-# Subscribe to a NATS subject
-NATS.subscribe("my.subject") do msg
-    # Process the message
-    result = NATSBridge.smartreceive(
-        msg,
-        max_retries = 5,
-        base_delay = 100,
-        max_delay = 5000
-    )
-    
-    # result is a list of (dataname, data, type) tuples
-    for (dataname, data, type) in result
-        println("Received $dataname of type $type")
-        println("Data: $data")
-    end
-end
-```
-
----
-
-## Payload Types
-
-NATSBridge.jl supports the following payload types:
-
-| Type | Description | Serialization |
-|------|-------------|---------------|
-| `text` | Plain text | UTF-8 encoding |
-| `dictionary` | JSON-serializable data (Dict, NamedTuple) | JSON |
-| `table` | Tabular data (DataFrame, array of structs) | Apache Arrow IPC |
-| `image` | Image data (Bitmap, PNG/JPG bytes) | Binary |
-| `audio` | Audio data (WAV, MP3 bytes) | Binary |
-| `video` | Video data (MP4, AVI bytes) | Binary |
-| `binary` | Generic binary data | Binary |
-
----
-
-## Transport Strategies
-
-NATSBridge.jl automatically selects the appropriate transport strategy based on payload size:
-
-### Direct Transport (< 1MB)
-
-Small payloads are encoded as Base64 and sent directly over NATS.
-
-```julia
-# Small data (< 1MB) - uses direct transport
-small_data = rand(1000)  # ~8KB
-env = NATSBridge.smartsend("small", [("data", small_data, "table")])
-```
-
-### Link Transport (≥ 1MB)
-
-Large payloads are uploaded to an HTTP file server, and only the URL is sent via NATS.
-
-```julia
-# Large data (≥ 1MB) - uses link transport
-large_data = rand(10_000_000)  # ~80MB
-env = NATSBridge.smartsend("large", [("data", large_data, "table")])
-```
-
----
-
-## Complete Examples
-
-### Example 1: Text Message
-
-**Sender:**
-```julia
-using NATSBridge
-using UUIDs
-
-const SUBJECT = "/NATSBridge_text_test"
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$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"]
-    
-    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
-
-function test_text_send()
-    small_text = "Hello, this is a small text message."
-    large_text = join(["Line $i: " for i in 1:50000], "")
-    
-    data1 = ("small_text", small_text, "text")
-    data2 = ("large_text", large_text, "text")
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [data1, data2],
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat",
-        sender_name = "text_sender"
-    )
-end
-```
-
-**Receiver:**
-```julia
-using NATSBridge
-
-const SUBJECT = "/NATSBridge_text_test"
-const NATS_URL = "nats://localhost:4222"
-
-function test_text_receive()
-    conn = NATS.connect(NATS_URL)
-    NATS.subscribe(conn, SUBJECT) do msg
-        result = NATSBridge.smartreceive(
-            msg,
-            max_retries = 5,
-            base_delay = 100,
-            max_delay = 5000
-        )
-        
-        for (dataname, data, data_type) in result
-            if data_type == "text"
-                println("Received text: $data")
-                write("./received_$dataname.txt", data)
-            end
-        end
-    end
-    sleep(120)
-    NATS.drain(conn)
-end
-```
-
-### Example 2: Dictionary (JSON) Message
-
-**Sender:**
-```julia
-using NATSBridge
-using UUIDs
-
-const SUBJECT = "/NATSBridge_dict_test"
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$fileserver_url/upload"
-    headers = ["Content-Type" => "application/json"]
-    body = """{ "OneShot" : true }"""
-    httpResponse = HTTP.request("POST", url_getUploadID, headers, body; body_is_form=false)
-    responseJson = JSON.parse(String(httpResponse.body))
-    uploadid = responseJson["id"]
-    uploadtoken = responseJson["uploadToken"]
-    
-    file_multipart = HTTP.Multipart(dataname, IOBuffer(data), "application/octet-stream")
-    url_upload = "$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/$dataname"
-    
-    return Dict("status" => httpResponse.status, "uploadid" => uploadid, "fileid" => fileid, "url" => url)
-end
-
-function test_dict_send()
-    small_dict = Dict("name" => "Alice", "age" => 30)
-    large_dict = Dict("ids" => collect(1:50000), "names" => ["User_$i" for i in 1:50000])
-    
-    data1 = ("small_dict", small_dict, "dictionary")
-    data2 = ("large_dict", large_dict, "dictionary")
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [data1, data2],
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat"
-    )
-end
-```
-
-**Receiver:**
-```julia
-using NATSBridge
-
-const SUBJECT = "/NATSBridge_dict_test"
-const NATS_URL = "nats://localhost:4222"
-
-function test_dict_receive()
-    conn = NATS.connect(NATS_URL)
-    NATS.subscribe(conn, SUBJECT) do msg
-        result = NATSBridge.smartreceive(
-            msg,
-            max_retries = 5,
-            base_delay = 100,
-            max_delay = 5000
-        )
-        
-        for (dataname, data, data_type) in result
-            if data_type == "dictionary"
-                println("Received dictionary: $data")
-                write("./received_$dataname.json", JSON.json(data, 2))
-            end
-        end
-    end
-    sleep(120)
-    NATS.drain(conn)
-end
-```
-
-### Example 3: DataFrame (Table) Message
-
-**Sender:**
-```julia
-using NATSBridge
-using DataFrames
-using UUIDs
-
-const SUBJECT = "/NATSBridge_table_test"
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$fileserver_url/upload"
-    headers = ["Content-Type" => "application/json"]
-    body = """{ "OneShot" : true }"""
-    httpResponse = HTTP.request("POST", url_getUploadID, headers, body; body_is_form=false)
-    responseJson = JSON.parse(String(httpResponse.body))
-    uploadid = responseJson["id"]
-    uploadtoken = responseJson["uploadToken"]
-    
-    file_multipart = HTTP.Multipart(dataname, IOBuffer(data), "application/octet-stream")
-    url_upload = "$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/$dataname"
-    
-    return Dict("status" => httpResponse.status, "uploadid" => uploadid, "fileid" => fileid, "url" => url)
-end
-
-function test_table_send()
-    small_df = DataFrame(id = 1:10, name = ["Alice", "Bob", "Charlie"], score = [95, 88, 92])
-    large_df = DataFrame(id = 1:50000, name = ["User_$i" for i in 1:50000], score = rand(1:100, 50000))
-    
-    data1 = ("small_table", small_df, "table")
-    data2 = ("large_table", large_df, "table")
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [data1, data2],
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat"
-    )
-end
-```
-
-**Receiver:**
-```julia
-using NATSBridge
-using DataFrames
-
-const SUBJECT = "/NATSBridge_table_test"
-const NATS_URL = "nats://localhost:4222"
-
-function test_table_receive()
-    conn = NATS.connect(NATS_URL)
-    NATS.subscribe(conn, SUBJECT) do msg
-        result = NATSBridge.smartreceive(
-            msg,
-            max_retries = 5,
-            base_delay = 100,
-            max_delay = 5000
-        )
-        
-        for (dataname, data, data_type) in result
-            if data_type == "table"
-                data = DataFrame(data)
-                println("Received DataFrame with $(size(data, 1)) rows")
-                display(data[1:min(5, size(data, 1)), :])
-            end
-        end
-    end
-    sleep(120)
-    NATS.drain(conn)
-end
-```
-
-### Example 4: Mixed Content (Chat with Text, Image, Audio)
-
-**Sender:**
-```julia
-using NATSBridge
-using DataFrames
-using UUIDs
-
-const SUBJECT = "/NATSBridge_mix_test"
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$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"]
-    
-    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
-
-function test_mix_send()
-    # Text data
-    text_data = "Hello! This is a test chat message. 🎉"
-    
-    # Dictionary data
-    dict_data = Dict("type" => "chat", "sender" => "serviceA")
-    
-    # Small table data
-    table_data_small = DataFrame(id = 1:10, name = ["msg_$i" for i in 1:10])
-    
-    # Large table data (link transport)
-    table_data_large = DataFrame(id = 1:150_000, name = ["msg_$i" for i in 1:150_000])
-    
-    # Small image data (direct transport)
-    image_data = UInt8[rand(1:255) for _ in 1:100]
-    
-    # Large image data (link transport)
-    large_image_data = UInt8[rand(1:255) for _ in 1:1_500_000]
-    
-    # Small audio data (direct transport)
-    audio_data = UInt8[rand(1:255) for _ in 1:100]
-    
-    # Large audio data (link transport)
-    large_audio_data = UInt8[rand(1:255) for _ in 1:1_500_000]
-    
-    # Small video data (direct transport)
-    video_data = UInt8[rand(1:255) for _ in 1:150]
-    
-    # Large video data (link transport)
-    large_video_data = UInt8[rand(1:255) for _ in 1:1_500_000]
-    
-    # Small binary data (direct transport)
-    binary_data = UInt8[rand(1:255) for _ in 1:200]
-    
-    # Large binary data (link transport)
-    large_binary_data = UInt8[rand(1:255) for _ in 1:1_500_000]
-    
-    # Create payloads list - mixed content
-    payloads = [
-        # Small data (direct transport)
-        ("chat_text", text_data, "text"),
-        ("chat_json", dict_data, "dictionary"),
-        ("chat_table_small", table_data_small, "table"),
-        
-        # Large data (link transport)
-        ("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")
-    ]
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        payloads,
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat",
-        sender_name = "mix_sender"
-    )
-end
-```
-
-**Receiver:**
-```julia
-using NATSBridge
-using DataFrames
-
-const SUBJECT = "/NATSBridge_mix_test"
-const NATS_URL = "nats://localhost:4222"
-
-function test_mix_receive()
-    conn = NATS.connect(NATS_URL)
-    NATS.subscribe(conn, SUBJECT) do msg
-        result = NATSBridge.smartreceive(
-            msg,
-            max_retries = 5,
-            base_delay = 100,
-            max_delay = 5000
-        )
-        
-        println("Received $(length(result)) payloads")
-        
-        for (dataname, data, data_type) in result
-            println("\n=== Payload: $dataname (type: $data_type) ===")
-            
-            if data_type == "text"
-                println("  Type: String")
-                println("  Length: $(length(data)) characters")
-                
-            elseif data_type == "dictionary"
-                println("  Type: JSON Object")
-                println("  Keys: $(keys(data))")
-                
-            elseif data_type == "table"
-                data = DataFrame(data)
-                println("  Type: DataFrame")
-                println("  Dimensions: $(size(data, 1)) rows x $(size(data, 2)) columns")
-                
-            elseif data_type == "image"
-                println("  Type: Vector{UInt8}")
-                println("  Size: $(length(data)) bytes")
-                write("./received_$dataname.bin", data)
-                
-            elseif data_type == "audio"
-                println("  Type: Vector{UInt8}")
-                println("  Size: $(length(data)) bytes")
-                write("./received_$dataname.bin", data)
-                
-            elseif data_type == "video"
-                println("  Type: Vector{UInt8}")
-                println("  Size: $(length(data)) bytes")
-                write("./received_$dataname.bin", data)
-                
-            elseif data_type == "binary"
-                println("  Type: Vector{UInt8}")
-                println("  Size: $(length(data)) bytes")
-                write("./received_$dataname.bin", data)
-            end
-        end
-    end
-    sleep(120)
-    NATS.drain(conn)
-end
-```
-
----
-
-## Best Practices
-
-1. **Always wrap payloads in a list** - Even for single payloads: `[("dataname", data, "type")]`
-2. **Use appropriate transport** - Let NATSBridge handle size-based routing (default 1MB threshold)
-3. **Customize size threshold** - Use `size_threshold` parameter to adjust the direct/link split
-4. **Provide fileserver handler** - Implement `fileserverUploadHandler` for link transport
-5. **Include correlation IDs** - Track messages across distributed systems
-6. **Handle errors** - Implement proper error handling for network failures
-7. **Close connections** - Ensure NATS connections are properly closed using `NATS.drain()`
-
----
-
-## Conclusion
-
-NATSBridge.jl provides a powerful abstraction for bi-directional communication between Julia and JavaScript services. By understanding the key concepts and following the best practices, you can build robust, scalable applications that leverage the full power of NATS messaging.
-
-For more information, see:
-- [`docs/architecture.md`](./architecture.md) - Detailed architecture documentation
-- [`docs/implementation.md`](./implementation.md) - Implementation details

walkthrough_julia.md

@@ -1,939 +0,0 @@
-# NATSBridge.jl Walkthrough: Building a Chat System
-
-A step-by-step guided walkthrough for building a real-time chat system using NATSBridge.jl with mixed content support (text, images, audio, video, and files).
-
-## Prerequisites
-
-- Julia 1.7+
-- NATS server running
-- HTTP file server (Plik) running
-
-## Step 1: Understanding the Chat System Architecture
-
-### System Components
-
-```
-┌─────────────────────────────────────────────────────────────────────────────┐
-│                              Chat System                                   │
-├─────────────────────────────────────────────────────────────────────────────┤
-│                                                                            │
-│  ┌──────────────┐        NATS         ┌──────────────┐                     │
-│  │   Julia      │◄───────┬───────►   │   JavaScript │                     │
-│  │  Service     │        │          │   Client     │                     │
-│  │              │        │          │              │                     │
-│  │ - Text       │        │          │ - Text       │                     │
-│  │ - Images     │        │          │ - Images     │                     │
-│  │ - Audio      │        ▼          │ - Audio      │                     │
-│  │ - Video      │  NATSBridge.jl    │ - Files      │                     │
-│  │ - Files      │        │          │ - Tables     │                     │
-│  └──────────────┘        │          └──────────────┘                     │
-│                          │                                                 │
-│                  ┌───────┴───────┐                                         │
-│                  │   NATS      │                                         │
-│                  │   Server    │                                         │
-│                  └─────────────┘                                         │
-│                                                                            │
-└─────────────────────────────────────────────────────────────────────────────┘
-
-For large payloads (> 1MB):
-┌─────────────────────────────────────────────────────────────────────────────┐
-│                           File Server (Plik)                               │
-│                                                                            │
-│  Julia Service ──► Upload ──► File Server ──► Download ◄── JavaScript Client│
-│                                                                            │
-└─────────────────────────────────────────────────────────────────────────────┘
-```
-
-### Message Format
-
-Each chat message is an envelope containing multiple payloads:
-
-```json
-{
-  "correlationId": "uuid4",
-  "msgId": "uuid4",
-  "timestamp": "2024-01-15T10:30:00Z",
-  "sendTo": "/chat/room1",
-  "msgPurpose": "chat",
-  "senderName": "user-1",
-  "senderId": "uuid4",
-  "receiverName": "user-2",
-  "receiverId": "uuid4",
-  "brokerURL": "nats://localhost:4222",
-  "payloads": [
-    {
-      "id": "uuid4",
-      "dataname": "message_text",
-      "type": "text",
-      "transport": "direct",
-      "encoding": "base64",
-      "size": 256,
-      "data": "SGVsbG8gV29ybGQh",
-      "metadata": {}
-    },
-    {
-      "id": "uuid4",
-      "dataname": "user_image",
-      "type": "image",
-      "transport": "link",
-      "encoding": "none",
-      "size": 15433,
-      "data": "http://localhost:8080/file/UPLOAD_ID/FILE_ID/image.jpg",
-      "metadata": {}
-    }
-  ]
-}
-```
-
-## Step 2: Setting Up the Environment
-
-### 1. Start NATS Server
-
-```bash
-# Using Docker
-docker run -d -p 4222:4222 -p 8222:8222 --name nats-server nats:latest
-
-# Or download from https://github.com/nats-io/nats-server/releases
-./nats-server
-```
-
-### 2. Start HTTP File Server (Plik)
-
-```bash
-# Using Docker
-docker run -d -p 8080:8080 --name plik plik/plik:latest
-
-# Or download from https://github.com/arnaud-lb/plik/releases
-./plikd -d
-```
-
-### 3. Install Julia Dependencies
-
-```julia
-using Pkg
-Pkg.add("NATS")
-Pkg.add("JSON")
-Pkg.add("Arrow")
-Pkg.add("HTTP")
-Pkg.add("UUIDs")
-Pkg.add("Dates")
-Pkg.add("Base64")
-Pkg.add("PrettyPrinting")
-Pkg.add("DataFrames")
-```
-
-## Step 3: Basic Text-Only Chat
-
-### Sender (User 1)
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-# Include the bridge module
-include("NATSBridge.jl")
-using .NATSBridge
-
-# Configuration
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-const SUBJECT = "/chat/room1"
-
-# File upload handler for plik server
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$fileserver_url/upload"
-    headers = ["Content-Type" => "application/json"]
-    body = """{ "OneShot" : true }"""
-    httpResponse = HTTP.request("POST", url_getUploadID, headers, body; body_is_form=false)
-    responseJson = JSON.parse(String(httpResponse.body))
-    uploadid = responseJson["id"]
-    uploadtoken = responseJson["uploadToken"]
-    
-    file_multipart = HTTP.Multipart(dataname, IOBuffer(data), "application/octet-stream")
-    url_upload = "$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
-
-# Send a simple text message
-function send_text_message()
-    message_text = "Hello, how are you today?"
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [("message", message_text, "text")],
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat",
-        sender_name = "user-1"
-    )
-    
-    println("Sent text message with correlation ID: $(env.correlationId)")
-end
-
-send_text_message()
-```
-
-### Receiver (User 2)
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-# Include the bridge module
-include("NATSBridge.jl")
-using .NATSBridge
-
-# Configuration
-const NATS_URL = "nats://localhost:4222"
-const SUBJECT = "/chat/room1"
-
-# Message handler
-function message_handler(msg::NATS.Msg)
-    payloads = NATSBridge.smartreceive(
-        msg,
-        max_retries = 5,
-        base_delay = 100,
-        max_delay = 5000
-    )
-    
-    # Extract the text message
-    for (dataname, data, data_type) in payloads
-        if data_type == "text"
-            println("Received message: $data")
-            # Save to file
-            write("./received_$dataname.txt", data)
-        end
-    end
-end
-
-# Subscribe to the chat room
-NATS.subscribe(SUBJECT) do msg
-    message_handler(msg)
-end
-
-# Keep the program running
-while true
-    sleep(1)
-end
-```
-
-## Step 4: Adding Image Support
-
-### Sending an Image
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-include("NATSBridge.jl")
-using .NATSBridge
-
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-const SUBJECT = "/chat/room1"
-
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$fileserver_url/upload"
-    headers = ["Content-Type" => "application/json"]
-    body = """{ "OneShot" : true }"""
-    httpResponse = HTTP.request("POST", url_getUploadID, headers, body; body_is_form=false)
-    responseJson = JSON.parse(String(httpResponse.body))
-    uploadid = responseJson["id"]
-    uploadtoken = responseJson["uploadToken"]
-    
-    file_multipart = HTTP.Multipart(dataname, IOBuffer(data), "application/octet-stream")
-    url_upload = "$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
-
-function send_image()
-    # Read image file
-    image_data = read("screenshot.png", Vector{UInt8})
-    
-    # Send with text message
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [
-            ("text", "Check out this screenshot!", "text"),
-            ("screenshot", image_data, "image")
-        ],
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat",
-        sender_name = "user-1"
-    )
-    
-    println("Sent image with correlation ID: $(env.correlationId)")
-end
-
-send_image()
-```
-
-### Receiving an Image
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-include("NATSBridge.jl")
-using .NATSBridge
-
-const NATS_URL = "nats://localhost:4222"
-const SUBJECT = "/chat/room1"
-
-function message_handler(msg::NATS.Msg)
-    payloads = NATSBridge.smartreceive(
-        msg,
-        max_retries = 5,
-        base_delay = 100,
-        max_delay = 5000
-    )
-    
-    for (dataname, data, data_type) in payloads
-        if data_type == "text"
-            println("Text: $data")
-        elseif data_type == "image"
-            # Save image to file
-            filename = "received_$dataname.bin"
-            write(filename, data)
-            println("Saved image: $filename")
-        end
-    end
-end
-
-NATS.subscribe(SUBJECT) do msg
-    message_handler(msg)
-end
-```
-
-## Step 5: Handling Large Files with Link Transport
-
-### Automatic Transport Selection
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-include("NATSBridge.jl")
-using .NATSBridge
-
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-const SUBJECT = "/chat/room1"
-
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$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"]
-    
-    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
-
-function send_large_file()
-    # Create a large file (> 1MB triggers link transport)
-    large_data = rand(10_000_000)  # ~80MB
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [("large_file", large_data, "binary")],
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat",
-        sender_name = "user-1"
-    )
-    
-    println("Uploaded large file to: $(env.payloads[1].data)")
-    println("Correlation ID: $(env.correlationId)")
-end
-
-send_large_file()
-```
-
-## Step 6: Audio and Video Support
-
-### Sending Audio
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-include("NATSBridge.jl")
-using .NATSBridge
-
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-const SUBJECT = "/chat/room1"
-
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$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"]
-    
-    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
-
-function send_audio()
-    # Read audio file (WAV, MP3, etc.)
-    audio_data = read("voice_message.mp3", Vector{UInt8})
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [("voice_message", audio_data, "audio")],
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat",
-        sender_name = "user-1"
-    )
-    
-    println("Sent audio message: $(env.correlationId)")
-end
-
-send_audio()
-```
-
-### Sending Video
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-include("NATSBridge.jl")
-using .NATSBridge
-
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-const SUBJECT = "/chat/room1"
-
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$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"]
-    
-    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
-
-function send_video()
-    # Read video file (MP4, AVI, etc.)
-    video_data = read("video_message.mp4", Vector{UInt8})
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [("video_message", video_data, "video")],
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat",
-        sender_name = "user-1"
-    )
-    
-    println("Sent video message: $(env.correlationId)")
-end
-
-send_video()
-```
-
-## Step 7: Table/Data Exchange
-
-### Sending Tabular Data
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-include("NATSBridge.jl")
-using .NATSBridge
-
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-const SUBJECT = "/chat/room1"
-
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$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"]
-    
-    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
-
-function send_table()
-    # Create a DataFrame
-    df = DataFrame(
-        id = 1:5,
-        name = ["Alice", "Bob", "Charlie", "Diana", "Eve"],
-        score = [95, 88, 92, 98, 85],
-        grade = ['A', 'B', 'A', 'B', 'B']
-    )
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [("student_scores", df, "table")],
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat",
-        sender_name = "user-1"
-    )
-    
-    println("Sent table with $(nrow(df)) rows")
-end
-
-send_table()
-```
-
-### Receiving and Using Tables
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-include("NATSBridge.jl")
-using .NATSBridge
-
-const NATS_URL = "nats://localhost:4222"
-const SUBJECT = "/chat/room1"
-
-function message_handler(msg::NATS.Msg)
-    payloads = NATSBridge.smartreceive(
-        msg,
-        max_retries = 5,
-        base_delay = 100,
-        max_delay = 5000
-    )
-    
-    for (dataname, data, data_type) in payloads
-        if data_type == "table"
-            data = DataFrame(data)
-            println("Received table:")
-            show(data)
-            println("\nAverage score: $(mean(data.score))")
-        end
-    end
-end
-
-NATS.subscribe(SUBJECT) do msg
-    message_handler(msg)
-end
-```
-
-## Step 8: Bidirectional Communication
-
-### Request-Response Pattern
-
-```julia
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-include("NATSBridge.jl")
-using .NATSBridge
-
-const NATS_URL = "nats://localhost:4222"
-const SUBJECT = "/api/query"
-const REPLY_SUBJECT = "/api/response"
-
-# Request
-function send_request()
-    query_data = Dict("query" => "SELECT * FROM users")
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        [("sql_query", query_data, "dictionary")],
-        nats_url = NATS_URL,
-        fileserver_url = "http://localhost:8080",
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "request",
-        sender_name = "frontend",
-        receiver_name = "backend",
-        reply_to = REPLY_SUBJECT,
-        reply_to_msg_id = string(uuid4())
-    )
-    
-    println("Request sent: $(env.correlationId)")
-end
-
-# Response handler
-function response_handler(msg::NATS.Msg)
-    payloads = NATSBridge.smartreceive(
-        msg,
-        max_retries = 5,
-        base_delay = 100,
-        max_delay = 5000
-    )
-    
-    for (dataname, data, data_type) in payloads
-        if data_type == "table"
-            data = DataFrame(data)
-            println("Query results:")
-            show(data)
-        end
-    end
-end
-
-NATS.subscribe(REPLY_SUBJECT) do msg
-    response_handler(msg)
-end
-```
-
-## Step 9: Complete Chat Application
-
-### Full Chat System
-
-```julia
-module ChatApp
-using NATS
-using JSON
-using UUIDs
-using Dates
-using PrettyPrinting
-using DataFrames
-using Arrow
-using HTTP
-using Base64
-
-# Include the bridge module
-include("../src/NATSBridge.jl")
-using .NATSBridge
-
-# Configuration
-const NATS_URL = "nats://localhost:4222"
-const FILESERVER_URL = "http://localhost:8080"
-const SUBJECT = "/chat/room1"
-
-# File upload handler for plik server
-function plik_upload_handler(fileserver_url::String, dataname::String, data::Vector{UInt8})::Dict{String, Any}
-    url_getUploadID = "$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"]
-    
-    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
-
-function send_chat_message(
-    text::String,
-    image_path::Union{String, Nothing}=nothing,
-    audio_path::Union{String, Nothing}=nothing
-)
-    # Build payloads list
-    payloads = [("message_text", text, "text")]
-    
-    if image_path !== nothing
-        image_data = read(image_path, Vector{UInt8})
-        push!(payloads, ("user_image", image_data, "image"))
-    end
-    
-    if audio_path !== nothing
-        audio_data = read(audio_path, Vector{UInt8})
-        push!(payloads, ("user_audio", audio_data, "audio"))
-    end
-    
-    env = NATSBridge.smartsend(
-        SUBJECT,
-        payloads,
-        nats_url = NATS_URL,
-        fileserver_url = FILESERVER_URL,
-        fileserverUploadHandler = plik_upload_handler,
-        size_threshold = 1_000_000,
-        correlation_id = string(uuid4()),
-        msg_purpose = "chat",
-        sender_name = "user-1"
-    )
-    
-    println("Message sent with correlation ID: $(env.correlationId)")
-end
-
-function receive_chat_messages()
-    function message_handler(msg::NATS.Msg)
-        payloads = NATSBridge.smartreceive(
-            msg,
-            max_retries = 5,
-            base_delay = 100,
-            max_delay = 5000
-        )
-        
-        println("\n--- New Message ---")
-        for (dataname, data, data_type) in payloads
-            if data_type == "text"
-                println("Text: $data")
-            elseif data_type == "image"
-                filename = "received_$dataname.bin"
-                write(filename, data)
-                println("Image saved: $filename")
-            elseif data_type == "audio"
-                filename = "received_$dataname.bin"
-                write(filename, data)
-                println("Audio saved: $filename")
-            elseif data_type == "table"
-                println("Table received:")
-                data = DataFrame(data)
-                show(data)
-            end
-        end
-    end
-    
-    NATS.subscribe(SUBJECT) do msg
-        message_handler(msg)
-    end
-    println("Subscribed to: $SUBJECT")
-end
-
-function run_interactive_chat()
-    println("\n=== Interactive Chat ===")
-    println("1. Send a message")
-    println("2. Join a chat room")
-    println("3. Exit")
-    
-    while true
-        print("\nSelect option (1-3): ")
-        choice = readline()
-        
-        if choice == "1"
-            print("Enter message text: ")
-            text = readline()
-            send_chat_message(text)
-        elseif choice == "2"
-            receive_chat_messages()
-        elseif choice == "3"
-            break
-        end
-    end
-end
-
-end # module
-
-# Run the chat app
-using .ChatApp
-ChatApp.run_interactive_chat()
-```
-
-## Step 10: Testing the Chat System
-
-### Test Scenario 1: Text-Only Chat
-
-```bash
-# Terminal 1: Start the chat receiver
-julia test_julia_to_julia_text_receiver.jl
-
-# Terminal 2: Send a message
-julia test_julia_to_julia_text_sender.jl
-```
-
-### Test Scenario 2: Image Chat
-
-```bash
-# Terminal 1: Receive messages
-julia test_julia_to_julia_mix_payloads_receiver.jl
-
-# Terminal 2: Send image
-julia test_julia_to_julia_mix_payload_sender.jl
-```
-
-### Test Scenario 3: Large File Transfer
-
-```bash
-# Terminal 2: Send large file
-julia test_julia_to_julia_mix_payload_sender.jl
-```
-
-## Conclusion
-
-This walkthrough demonstrated how to build a chat system using NATSBridge.jl with support for:
-
-- Text messages
-- Images (direct transport for small, link transport for large)
-- Audio files
-- Video files
-- Tabular data (DataFrames)
-- Bidirectional communication
-- Mixed-content messages
-
-The key takeaways are:
-
-1. **Always wrap payloads in a list** - Even for single payloads: `[("dataname", data, "type")]`
-2. **Use appropriate transport** - NATSBridge automatically handles size-based routing
-3. **Support mixed content** - Multiple payloads of different types in one message
-4. **Handle errors** - Implement proper error handling for network failures
-5. **Use correlation IDs** - Track messages across distributed systems
-
-For more information, see:
-- [`docs/architecture.md`](./docs/architecture.md) - Detailed architecture documentation
-- [`docs/implementation.md`](./docs/implementation.md) - Implementation details