Websocket Implementation

WebSocket Implementation

Build scalable real-time communication systems with proper connection management.

Server Implementation (Socket.IO)

const { Server } = require('socket.io');
const { createAdapter } = require('@socket.io/redis-adapter');
const { createClient } = require('redis');

const io = new Server(server, {
  cors: { origin: process.env.CLIENT_URL, credentials: true }
});

// Redis adapter for horizontal scaling
const pubClient = createClient({ url: process.env.REDIS_URL });
const subClient = pubClient.duplicate();
Promise.all([pubClient.connect(), subClient.connect()]).then(() => {
  io.adapter(createAdapter(pubClient, subClient));
});

// Connection management
const users = new Map();

io.use((socket, next) => {
  const token = socket.handshake.auth.token;
  try {
    socket.user = verifyToken(token);
    next();
  } catch (err) {
    next(new Error('Authentication failed'));
  }
});

io.on('connection', (socket) => {
  users.set(socket.user.id, socket.id);
  console.log(`User ${socket.user.id} connected`);

  socket.on('join-room', (roomId) => {
    socket.join(roomId);
    socket.to(roomId).emit('user-joined', socket.user);
  });