Socket.io - Complete Guide

Here's a comprehensive roadmap for Socket.io, including structured concepts, example code snippets

1. Introduction to Socket.io:

• What is Socket.io?
• Real-time communication in web applications.
• Setting up a Socket.io server and client.

2. Basics of Socket.io:

• Emitting and receiving events.
• Broadcasting messages.
• Example: Building a real-time chat application with Socket.io.

// Server-side
const io = require('socket.io')(http);

io.on('connection', (socket) => {
  console.log('A user connected');
  
  socket.on('chat message', (msg) => {
    io.emit('chat message', msg);
  });
});

// Client-side
const socket = io();
socket.emit('chat message', 'Hello, world!');        

3. Namespaces and Rooms:

• Creating namespaces for grouping sockets.
• Using rooms for targeted communication.
• Example: Implementing namespaces and rooms for chat rooms.

// Server-side
const chatNamespace = io.of('/chat');
chatNamespace.on('connection', (socket) => {
  socket.join('room1');
  socket.to('room1').emit('message', 'A user joined room1');
});        

4. Handling Disconnections:

• Detecting and handling socket disconnections.
• Reconnecting and disconnecting manually.
• Example: Handling disconnect events and notifying other users.

// Server-side
io.on('connection', (socket) => {
  socket.on('disconnect', () => {
    console.log('A user disconnected');
  });
});        

5. Advanced Features:

• Middleware in Socket.io.
• Authenticating and authorizing socket connections.
• Implementing custom namespaces and room logic.
• Broadcasting to specific rooms.

6. Scaling with Socket.io:

• Using Redis for scaling across multiple servers.
• Implementing load balancing.
• Handling large-scale real-time applications.

Github :

https://github.com/socketio

https://github.com/socketio/socket.io

https://socket.io/