What is Socket.IO?
Socket.IO is a library that enables real-time, bidirectional, and event-based communication between a client and server.
Key Concepts
- On the client-side, it uses WebSocket (or otherwise, falls back to HTTP long-polling)
- NOT a 100% drop-in replacement for WebSocket, but the API is similar
// client-side
const socket = io('ws://localhost:3000');
socket.on('connect', () => {
console.log(socket.id); // x8WIv7-mJ...
});
// server-side
io.on('connection', (socket) => {
console.debug('Someone has connected!');
});
- Provides a Node.js server implementation
I mean, but why?
- Falls back to HTTP long-polling in case the WebSocket connection cannot be established
- Automatic reconnection
- Supports broadcasting to all clients or a subset (aka a 'room')
- Multiplexing aka namespacing
socket.io
By Cameron Sampson
