674 lines
23 KiB
JavaScript
674 lines
23 KiB
JavaScript
/**
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* NATSBridge - Cross-Platform Bi-Directional Data Bridge
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* JavaScript/Node.js Implementation
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*
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* This module provides functionality for sending and receiving data across network boundaries
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* using NATS as the message bus, with support for both direct payload transport and
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* URL-based transport for larger payloads.
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*
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* @module NATSBridge
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*/
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const nats = require('nats');
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const { v4: uuidv4 } = require('uuid');
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const fetch = require('node-fetch');
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const arrow = require('apache-arrow');
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// ---------------------------------------------- Constants ---------------------------------------------- //
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/**
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* Default size threshold for switching from direct to link transport (1MB)
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*/
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const DEFAULT_SIZE_THRESHOLD = 1_000_000;
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/**
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* Default NATS server URL
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*/
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const DEFAULT_BROKER_URL = 'nats://localhost:4222';
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/**
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* Default HTTP file server URL for link transport
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*/
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const DEFAULT_FILESERVER_URL = 'http://localhost:8080';
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// ---------------------------------------------- Utility Functions ---------------------------------------------- //
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/**
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* Convert Buffer to Base64 string
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* @param {Buffer} buffer - Buffer to encode
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* @returns {string} Base64 encoded string
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*/
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function bufferToBase64(buffer) {
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return buffer.toString('base64');
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}
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/**
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* Log a trace message with correlation ID and timestamp
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* @param {string} correlationId - Correlation ID for tracing
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* @param {string} message - Message content to log
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*/
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function logTrace(correlationId, message) {
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const timestamp = new Date().toISOString();
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console.log(`[${timestamp}] [Correlation: ${correlationId}] ${message}`);
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}
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// ---------------------------------------------- Serialization Functions ---------------------------------------------- //
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/**
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* Serialize data according to specified format
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* @param {any} data - Data to serialize
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* @param {string} payloadType - Target format: "text", "dictionary", "table", "image", "audio", "video", "binary"
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* @returns {Buffer} Binary representation of the serialized data
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*/
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async function serializeData(data, payloadType) {
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if (payloadType === 'text') {
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if (typeof data === 'string') {
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return Buffer.from(data, 'utf8');
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} else {
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throw new Error('Text data must be a string');
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}
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} else if (payloadType === 'dictionary') {
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const jsonStr = JSON.stringify(data);
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return Buffer.from(jsonStr, 'utf8');
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} else if (payloadType === 'table') {
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// Convert array of objects to Arrow IPC format
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if (!Array.isArray(data) || data.length === 0) {
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throw new Error('Table data must be a non-empty array of objects');
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}
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return serializeArrowTable(data);
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} else if (payloadType === 'image') {
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if (data instanceof Uint8Array || Buffer.isBuffer(data)) {
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return Buffer.from(data);
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} else {
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throw new Error('Image data must be Uint8Array or Buffer');
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}
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} else if (payloadType === 'audio') {
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if (data instanceof Uint8Array || Buffer.isBuffer(data)) {
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return Buffer.from(data);
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} else {
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throw new Error('Audio data must be Uint8Array or Buffer');
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}
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} else if (payloadType === 'video') {
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if (data instanceof Uint8Array || Buffer.isBuffer(data)) {
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return Buffer.from(data);
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} else {
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throw new Error('Video data must be Uint8Array or Buffer');
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}
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} else if (payloadType === 'binary') {
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if (data instanceof Uint8Array || Buffer.isBuffer(data)) {
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return Buffer.from(data);
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} else {
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throw new Error('Binary data must be Uint8Array or Buffer');
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}
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} else {
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throw new Error(`Unknown payload_type: ${payloadType}`);
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}
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}
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/**
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* Helper function to properly serialize table data to Arrow IPC
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* @param {Array<Object>} data - Array of objects representing table rows
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* @returns {Buffer} Arrow IPC formatted buffer
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*/
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function serializeArrowTable(data) {
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if (!Array.isArray(data) || data.length === 0) {
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throw new Error('Table data must be a non-empty array of objects');
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}
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// Build schema from first row
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const fields = Object.keys(data[0]).map(key => {
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const value = data[0][key];
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let arrowType;
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if (typeof value === 'number') {
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arrowType = Number.isInteger(value) ? arrow.Int64 : arrow.Float64;
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} else if (typeof value === 'boolean') {
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arrowType = arrow.Boolean;
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} else if (value instanceof Date) {
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arrowType = arrow.Date;
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} else {
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arrowType = arrow.Utf8;
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}
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return new arrow.Field(key, arrowType, true);
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});
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const schema = new arrow.Schema(fields);
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const batches = [];
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// Create record batches
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for (const row of data) {
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const batch = arrow.recordBatch.fromObjects([row], schema);
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batches.push(batch);
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}
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// Write to buffer using IPC format
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const buffers = arrow.ipc.recordBatchesToMessage(batches, schema).buffers;
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const combined = new Uint8Array(buffers.reduce((acc, b) => acc + b.byteLength, 0));
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let offset = 0;
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for (const buf of buffers) {
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combined.set(new Uint8Array(buf), offset);
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offset += buf.byteLength;
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}
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return Buffer.from(combined);
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}
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/**
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* Deserialize bytes to data based on type
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* @param {Buffer|Uint8Array} data - Serialized data as bytes
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* @param {string} payloadType - Data type
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* @param {string} correlationId - Correlation ID for logging
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* @returns {any} Deserialized data
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*/
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async function deserializeData(data, payloadType, correlationId) {
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const buffer = Buffer.isBuffer(data) ? data : Buffer.from(data);
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if (payloadType === 'text') {
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return buffer.toString('utf8');
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} else if (payloadType === 'dictionary') {
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const jsonStr = buffer.toString('utf8');
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return JSON.parse(jsonStr);
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} else if (payloadType === 'table') {
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const table = arrow.tableFromRawBytes(buffer);
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return table;
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} else if (payloadType === 'image') {
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return buffer;
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} else if (payloadType === 'audio') {
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return buffer;
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} else if (payloadType === 'video') {
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return buffer;
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} else if (payloadType === 'binary') {
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return buffer;
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} else {
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throw new Error(`Unknown payload_type: ${payloadType}`);
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}
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}
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// ---------------------------------------------- File Server Handlers ---------------------------------------------- //
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/**
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* Upload data to plik server in one-shot mode
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* @param {string} fileServerUrl - Base URL of the plik server
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* @param {string} dataname - Name of the file being uploaded
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* @param {Buffer|Uint8Array} data - Raw byte data of the file content
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* @returns {Promise<{status: number, uploadid: string, fileid: string, url: string}>}
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*/
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async function plikOneshotUpload(fileServerUrl, dataname, data) {
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const buffer = Buffer.isBuffer(data) ? data : Buffer.from(data);
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// Get upload id
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const urlGetUploadID = `${fileServerUrl}/upload`;
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const headers = { 'Content-Type': 'application/json' };
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const body = JSON.stringify({ OneShot: true });
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const httpResponse = await fetch(urlGetUploadID, {
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method: 'POST',
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headers,
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body
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});
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const responseJson = await httpResponse.json();
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const uploadid = responseJson.id;
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const uploadtoken = responseJson.uploadToken;
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// Upload file
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const urlUpload = `${fileServerUrl}/file/${uploadid}`;
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const form = new FormData();
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const blob = new Blob([buffer], { type: 'application/octet-stream' });
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form.append('file', blob, dataname);
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const uploadHeaders = {
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'X-UploadToken': uploadtoken
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};
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const uploadResponse = await fetch(urlUpload, {
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method: 'POST',
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headers: uploadHeaders,
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body: form
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});
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const uploadJson = await uploadResponse.json();
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const fileid = uploadJson.id;
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const url = `${fileServerUrl}/file/${uploadid}/${fileid}/${dataname}`;
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return {
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status: uploadResponse.status,
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uploadid,
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fileid,
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url
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};
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}
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/**
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* Fetch data from URL with exponential backoff
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* @param {string} url - URL to fetch from
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* @param {number} maxRetries - Maximum number of retry attempts
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* @param {number} baseDelay - Initial delay in milliseconds
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* @param {number} maxDelay - Maximum delay in milliseconds
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* @param {string} correlationId - Correlation ID for logging
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* @returns {Promise<Uint8Array>} Fetched data as bytes
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*/
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async function fetchWithBackoff(url, maxRetries, baseDelay, maxDelay, correlationId) {
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let delay = baseDelay;
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for (let attempt = 1; attempt <= maxRetries; attempt++) {
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try {
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const response = await fetch(url);
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if (response.status === 200) {
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logTrace(correlationId, `Successfully fetched data from ${url} on attempt ${attempt}`);
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const arrayBuffer = await response.arrayBuffer();
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return new Uint8Array(arrayBuffer);
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} else {
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throw new Error(`Failed to fetch: ${response.status}`);
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}
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} catch (e) {
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logTrace(correlationId, `Attempt ${attempt} failed: ${e.constructor.name}`);
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if (attempt < maxRetries) {
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await new Promise(resolve => setTimeout(resolve, delay));
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delay = Math.min(delay * 2, maxDelay);
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}
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}
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}
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throw new Error(`Failed to fetch data after ${maxRetries} attempts`);
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}
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// ---------------------------------------------- NATS Client ---------------------------------------------- //
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/**
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* NATS client wrapper for connection management
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*/
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class NATSClient {
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/**
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* Create a new NATS client
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* @param {string} url - NATS server URL
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*/
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constructor(url) {
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this.url = url;
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this.connection = null;
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}
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/**
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* Connect to NATS server
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* @returns {Promise<NATS.Connection>}
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*/
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async connect() {
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this.connection = await nats.connect({ servers: this.url });
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return this.connection;
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}
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/**
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* Publish message to NATS subject
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* @param {string} subject - NATS subject to publish to
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* @param {string} message - Message to publish
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* @param {string} correlationId - Correlation ID for logging
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*/
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async publish(subject, message, correlationId) {
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if (!this.connection) {
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await this.connect();
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}
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await this.connection.publish(subject, message);
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logTrace(correlationId, `Message published to ${subject}`);
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}
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/**
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* Close the NATS connection
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*/
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async close() {
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if (this.connection) {
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this.connection.close();
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}
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}
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}
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// ---------------------------------------------- Core Functions ---------------------------------------------- //
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/**
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* Publish message to NATS
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* @param {string|NATSClient|NATS.Connection} brokerUrlOrClient - NATS URL, client, or connection
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* @param {string} subject - NATS subject to publish to
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* @param {string} message - JSON message to publish
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* @param {string} correlationId - Correlation ID for tracing
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*/
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async function publishMessage(brokerUrlOrClient, subject, message, correlationId) {
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let conn;
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if (brokerUrlOrClient instanceof NATSClient) {
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conn = brokerUrlOrClient;
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} else if (brokerUrlOrClient instanceof nats.Connection) {
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// Create a wrapper for direct connection
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conn = {
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async publish(subj, msg) {
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await brokerUrlOrClient.publish(subj, msg);
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},
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async close() {
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await brokerUrlOrClient.close();
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}
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};
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} else {
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// String URL - create new client
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const client = new NATSClient(brokerUrlOrClient);
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conn = client;
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}
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await conn.publish(subject, message, correlationId);
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if (conn instanceof NATSClient) {
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await conn.close();
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}
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}
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/**
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* Build message envelope from payloads and metadata
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* @param {string} subject - NATS subject
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* @param {Array} payloads - Array of payload objects
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* @param {Object} options - Envelope metadata options
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* @returns {Object} Envelope object
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*/
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function buildEnvelope(subject, payloads, options) {
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return {
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correlation_id: options.correlation_id,
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msg_id: options.msg_id,
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timestamp: new Date().toISOString(),
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send_to: subject,
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msg_purpose: options.msg_purpose,
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sender_name: options.sender_name,
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sender_id: options.sender_id,
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receiver_name: options.receiver_name,
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receiver_id: options.receiver_id,
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reply_to: options.reply_to,
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reply_to_msg_id: options.reply_to_msg_id,
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broker_url: options.broker_url,
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metadata: options.metadata || {},
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payloads: payloads
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};
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}
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/**
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* Build payload object from serialized data
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* @param {string} dataname - Name of the payload
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* @param {string} payloadType - Type of the payload
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* @param {Buffer} payloadBytes - Serialized payload bytes
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* @param {string} transport - Transport type ("direct" or "link")
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* @param {string} data - Data (base64 for direct, URL for link)
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* @returns {Object} Payload object
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*/
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function buildPayload(dataname, payloadType, payloadBytes, transport, data) {
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return {
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id: uuidv4(),
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dataname,
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payload_type: payloadType,
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transport,
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encoding: transport === 'direct' ? 'base64' : 'none',
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size: payloadBytes.byteLength,
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data,
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metadata: transport === 'direct' ? { payload_bytes: payloadBytes.byteLength } : {}
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};
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}
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/**
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* Send data via NATS with automatic transport selection
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*
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* This function intelligently routes data delivery based on payload size.
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* If the serialized payload is smaller than size_threshold, it encodes the data as Base64
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* and publishes directly over NATS. Otherwise, it uploads the data to a fileserver
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* and publishes only the download URL over NATS.
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*
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* @param {string} subject - NATS subject to publish the message to
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* @param {Array} data - List of [dataname, data, type] tuples to send
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* @param {Object} options - Optional configuration
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* @param {string} [options.broker_url=DEFAULT_BROKER_URL] - URL of the NATS server
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* @param {string} [options.fileserver_url=DEFAULT_FILESERVER_URL] - URL of the HTTP file server
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* @param {Function} [options.fileserver_upload_handler=plikOneshotUpload] - Function to handle fileserver uploads
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* @param {number} [options.size_threshold=DEFAULT_SIZE_THRESHOLD] - Threshold separating direct vs link transport
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* @param {string} [options.correlation_id=uuidv4()] - Correlation ID for tracing
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* @param {string} [options.msg_purpose="chat"] - Purpose of the message
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* @param {string} [options.sender_name="NATSBridge"] - Name of the sender
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* @param {string} [options.receiver_name=""] - Name of the receiver (empty means broadcast)
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* @param {string} [options.receiver_id=""] - UUID of the receiver (empty means broadcast)
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* @param {string} [options.reply_to=""] - Topic to reply to
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* @param {string} [options.reply_to_msg_id=""] - Message ID this message is replying to
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* @param {boolean} [options.is_publish=true] - Whether to automatically publish the message
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* @param {NATSClient|NATS.Connection} [options.nats_connection=null] - Pre-existing NATS connection
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* @param {string} [options.msg_id=uuidv4()] - Message ID
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* @param {string} [options.sender_id=uuidv4()] - Sender ID
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* @returns {Promise<[Object, string]>} Tuple of [env, env_json_str]
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*
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* @example
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* // Send a single payload
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* const [env, envJsonStr] = await smartsend(
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* "/test",
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* [["dataname1", data1, "dictionary"]],
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* { broker_url: "nats://localhost:4222" }
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* );
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*
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* // Send multiple payloads
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* const [env, envJsonStr] = await smartsend(
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* "/test",
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* [
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* ["dataname1", data1, "dictionary"],
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* ["dataname2", data2, "table"]
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* ],
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* { broker_url: "nats://localhost:4222" }
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* );
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*
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* // Send with pre-existing connection
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* const client = await NATSBridge.NATSClient.connect("nats://localhost:4222");
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* const [env, envJsonStr] = await smartsend(
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* "/test",
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* [["data", myData, "text"]],
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* { nats_connection: client }
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* );
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*/
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async function smartsend(subject, data, options = {}) {
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const {
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broker_url = DEFAULT_BROKER_URL,
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fileserver_url = DEFAULT_FILESERVER_URL,
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fileserver_upload_handler = plikOneshotUpload,
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size_threshold = DEFAULT_SIZE_THRESHOLD,
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correlation_id = uuidv4(),
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msg_purpose = 'chat',
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sender_name = 'NATSBridge',
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receiver_name = '',
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receiver_id = '',
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reply_to = '',
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reply_to_msg_id = '',
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is_publish = true,
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nats_connection = null,
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msg_id = uuidv4(),
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sender_id = uuidv4()
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} = options;
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logTrace(correlation_id, `Starting smartsend for subject: ${subject}`);
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// Process payloads
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const payloads = [];
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for (const [dataname, payloadData, payloadType] of data) {
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const payloadBytes = await serializeData(payloadData, payloadType);
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const payloadSize = payloadBytes.byteLength;
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logTrace(correlation_id, `Serialized payload '${dataname}' (type: ${payloadType}) size: ${payloadSize} bytes`);
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if (payloadSize < size_threshold) {
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// Direct path
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const payloadB64 = bufferToBase64(payloadBytes);
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logTrace(correlation_id, `Using direct transport for ${payloadSize} bytes`);
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const payload = buildPayload(dataname, payloadType, payloadBytes, 'direct', payloadB64);
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payloads.push(payload);
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} else {
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// Link path
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logTrace(correlation_id, `Using link transport, uploading to fileserver`);
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const response = await fileserver_upload_handler(fileserver_url, dataname, payloadBytes);
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if (response.status !== 200) {
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throw new Error(`Failed to upload data to fileserver: ${response.status}`);
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}
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logTrace(correlation_id, `Uploaded to URL: ${response.url}`);
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|
const payload = buildPayload(dataname, payloadType, payloadBytes, 'link', response.url);
|
|
payloads.push(payload);
|
|
}
|
|
}
|
|
|
|
// Build envelope
|
|
const env = buildEnvelope(subject, payloads, {
|
|
correlation_id,
|
|
msg_id,
|
|
msg_purpose,
|
|
sender_name,
|
|
sender_id,
|
|
receiver_name,
|
|
receiver_id,
|
|
reply_to,
|
|
reply_to_msg_id,
|
|
broker_url
|
|
});
|
|
|
|
const env_json_str = JSON.stringify(env);
|
|
|
|
if (is_publish) {
|
|
if (nats_connection) {
|
|
await publishMessage(nats_connection, subject, env_json_str, correlation_id);
|
|
} else {
|
|
await publishMessage(broker_url, subject, env_json_str, correlation_id);
|
|
}
|
|
}
|
|
|
|
return [env, env_json_str];
|
|
}
|
|
|
|
/**
|
|
* Receive and process NATS message
|
|
*
|
|
* This function processes incoming NATS messages, handling both direct transport
|
|
* (base64 decoded payloads) and link transport (URL-based payloads).
|
|
* It deserializes the data based on the transport type and returns the result.
|
|
*
|
|
* @param {Object} msg - NATS message object with payload property
|
|
* @param {Object} options - Optional configuration
|
|
* @param {Function} [options.fileserver_download_handler=fetchWithBackoff] - Function to handle fileserver downloads
|
|
* @param {number} [options.max_retries=5] - Maximum retry attempts for fetching URL
|
|
* @param {number} [options.base_delay=100] - Initial delay for exponential backoff in ms
|
|
* @param {number} [options.max_delay=5000] - Maximum delay for exponential backoff in ms
|
|
* @returns {Promise<Object>} Envelope object with processed payloads
|
|
*
|
|
* @example
|
|
* // Receive and process message
|
|
* const env = await smartreceive(msg, {
|
|
* fileserver_download_handler: fetchWithBackoff,
|
|
* max_retries: 5,
|
|
* base_delay: 100,
|
|
* max_delay: 5000
|
|
* });
|
|
* // env.payloads is an Array of [dataname, data, type] arrays
|
|
* for (const [dataname, data, type] of env.payloads) {
|
|
* console.log(`${dataname}: ${data} (type: ${type})`);
|
|
* }
|
|
*/
|
|
async function smartreceive(msg, options = {}) {
|
|
const {
|
|
fileserver_download_handler = fetchWithBackoff,
|
|
max_retries = 5,
|
|
base_delay = 100,
|
|
max_delay = 5000
|
|
} = options;
|
|
|
|
// Parse the JSON envelope
|
|
const payload = typeof msg.payload === 'string' ? msg.payload : Buffer.from(msg.payload).toString('utf8');
|
|
const envJsonObj = JSON.parse(payload);
|
|
logTrace(envJsonObj.correlation_id, 'Processing received message');
|
|
|
|
// Process all payloads in the envelope
|
|
const payloadsList = [];
|
|
const numPayloads = envJsonObj.payloads.length;
|
|
|
|
for (let i = 0; i < numPayloads; i++) {
|
|
const payloadObj = envJsonObj.payloads[i];
|
|
const transport = payloadObj.transport;
|
|
const dataname = payloadObj.dataname;
|
|
|
|
if (transport === 'direct') {
|
|
logTrace(envJsonObj.correlation_id, `Direct transport - decoding payload '${dataname}'`);
|
|
|
|
// Extract base64 payload from the payload
|
|
const payloadB64 = payloadObj.data;
|
|
|
|
// Decode Base64 payload
|
|
const payloadBytes = Buffer.from(payloadB64, 'base64');
|
|
|
|
// Deserialize based on type
|
|
const dataType = payloadObj.payload_type;
|
|
const data = await deserializeData(payloadBytes, dataType, envJsonObj.correlation_id);
|
|
|
|
payloadsList.push([dataname, data, dataType]);
|
|
} else if (transport === 'link') {
|
|
// Extract download URL from the payload
|
|
const url = payloadObj.data;
|
|
logTrace(envJsonObj.correlation_id, `Link transport - fetching '${dataname}' from URL: ${url}`);
|
|
|
|
// Fetch with exponential backoff using the download handler
|
|
const downloadedData = await fileserver_download_handler(
|
|
url,
|
|
max_retries,
|
|
base_delay,
|
|
max_delay,
|
|
envJsonObj.correlation_id
|
|
);
|
|
|
|
// Deserialize based on type
|
|
const dataType = payloadObj.payload_type;
|
|
const data = await deserializeData(downloadedData, dataType, envJsonObj.correlation_id);
|
|
|
|
payloadsList.push([dataname, data, dataType]);
|
|
} else {
|
|
throw new Error(`Unknown transport type for payload '${dataname}': ${transport}`);
|
|
}
|
|
}
|
|
|
|
envJsonObj.payloads = payloadsList;
|
|
return envJsonObj;
|
|
}
|
|
|
|
// ---------------------------------------------- Module Exports ---------------------------------------------- //
|
|
|
|
const NATSBridge = {
|
|
/**
|
|
* NATS client class for connection management
|
|
*/
|
|
NATSClient,
|
|
|
|
/**
|
|
* Send data via NATS with automatic transport selection
|
|
*/
|
|
smartsend,
|
|
|
|
/**
|
|
* Receive and process NATS message
|
|
*/
|
|
smartreceive,
|
|
|
|
/**
|
|
* Upload data to plik server in one-shot mode
|
|
*/
|
|
plikOneshotUpload,
|
|
|
|
/**
|
|
* Fetch data from URL with exponential backoff
|
|
*/
|
|
fetchWithBackoff,
|
|
|
|
/**
|
|
* Default constants
|
|
*/
|
|
DEFAULT_SIZE_THRESHOLD,
|
|
DEFAULT_BROKER_URL,
|
|
DEFAULT_FILESERVER_URL
|
|
};
|
|
|
|
module.exports = NATSBridge; |