How can I implement authentication in Socket.IO?

How can I implement authentication in Socket.IO?

You can implement authentication in Socket.IO by using middleware to verify user tokens before establishing a connection.

What kind of authentication tokens should I use?

JWT (JSON Web Tokens) are commonly used for authentication in Socket.IO due to their stateless nature.

Can you show me a code example?

Sure! Here's a basic example:

const io = require('socket.io')(server);
const jwt = require('jsonwebtoken');

io.use((socket, next) => {
  const token = socket.handshake.query.token;
  jwt.verify(token, 'your_secret_key', (err, decoded) => {
    if (err) return next(new Error('Authentication error'));
    socket.user = decoded;
    next();
  });
});

What if the token is expired?

You should handle expired tokens by prompting the user to re-authenticate and obtain a new token.