Message Broker WebSocket Client (mb-client-js)

A TypeScript library for reliable WebSocket communication with the Message Broker server. Features automatic reconnection, heartbeat monitoring, request/response handling, and event-based communication.

Features

• 🔄 Automatic reconnection with configurable delay
• 💓 Heartbeat monitoring for connection health
• 🤝 Promise-based request/response pattern
• 📡 Event-based message handling
• 📊 Connection state monitoring and events
• ⚡ Efficient message serialization
• 📝 TypeScript support with full type definitions

Installation

npm install mb-client

Quick Start

import { WebSocketClient } from 'mb-client';

// Create a client instance
const client = new WebSocketClient({
    url: 'ws://localhost:3000'
});

// Connect to the server
client.connect();

// Listen for connection events
client.on('connected', () => {
    console.log('Connected to server!');
});

// Make a request
try {
    const response = await client.request('my.topic', { some: 'data' });
    console.log('Response:', response);
} catch (error) {
    console.error('Request failed:', error);
}

// Publish a message
await client.publish('my.topic', { hello: 'world' });

API Reference

WebSocketClient

The main client class for WebSocket communication.

Constructor

new WebSocketClient(config: Partial<WebSocketConfig> & Pick<WebSocketConfig, 'url'>)

Configuration options:

• url (required): WebSocket server URL
• heartbeatInterval (optional): Interval between heartbeats in ms (default: 10000)
• reconnectDelay (optional): Delay before reconnection attempts in ms (default: 5000)
• maxRecentEvents (optional): Maximum number of recent events to keep (default: 50)
• protocolVersion (optional): Protocol version string (default: '1.0.0')

Methods

• connect(url?: string): void - Connect to the server
• disconnect(): void - Disconnect from the server
• request(topic: string, payload?: any, timeout?: number): Promise<any> - Make a request
• publish(topic: string, payload?: any): Promise<void> - Publish a message

Events

• 'connected' - Connection established
• 'disconnected' - Connection lost
• 'error' - Connection error
• 'stateChange' - Connection state changed
• 'connectionEvent' - Connection event occurred
• 'latencyUpdate' - Connection latency updated

Message Format

Messages are serialized in the following format:

action:topic:version[:requestId]
{"key": "value"}

Where:

• First line: Header with action, topic, version, and optional requestId
• Second line: JSON payload

Connection States

• CONNECTED - Successfully connected to the server
• CONNECTING - Initial connection attempt
• RECONNECTING - Attempting to reconnect
• DISCONNECTED - Not connected to the server

Development

# Install dependencies
npm install

# Build the library
npm run build

# Run tests
npm test

# Lint code
npm run lint

# Format code
npm run format

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.