CODEWITHSUNDEEP
node.jssocket.io
Eric Jansen
Eric Jansen

Reputation: 440

Socket.IO multiple files server-side

I have a nodejs backend and a react frontend. On nodejs I have socketio set up, on the client side I have the connection in the App component, and passed down using context. Now, using hooks, I can use the io variable globally and listen on client-side to events.

However, on server side, I have this IO variable also globally available, but how to use this on multiple pages? I have this code in server.ts:

const io = //initialize io
io.on('connection', (socket: any) => {
    console.log('a user connected', socket.handshake.query);

    socket.on('disconnect', () => {
        console.log('user disconnected');
    });

    io.on('test', console.log);
});

But, in a different file, I have to initialize my connection using io.on()again. How to work around this? I have a file called foo.controller.ts which has some actions around foo. In this file I want to listen all events related to foo.

Upvotes: 0

Views: 1233

Answers (1)

Damian Plewa
Damian Plewa

Reputation: 1193

Create new file ex. socket.instance.js, then create class to handle all socket's logic, like storing sockets list or something (it's up to you what you need);

Here is example of socket.instance.js:

const Subject = require('rxjs').Subject;
class SocketInstance {
  io = require('socket.io')();
  sockets = new Set();
  newSocket = new Subject();

  constructor() {
    this.io.listen(process.env.PORT);

    this.io.on('connect', socket => {
      this.sockets.add(socket);

      this.handleNewSocket(socket);

      socket.on('disconnect', () => {
        this.sockets.delete(socket);
      });

      this.newSocket.next(socket);
    });
  }

  handleNewSocket(socket) {
    // logic here
  }
}

const socketInstance = new SocketInstance();

module.exports = {socketInstance}

Then in any other file you can access to this instance like this:

// anotherServerFile.js
const socketInstance = require('./socket.instance').socketInstance;

socketInstance.io.emit('hello');

// yetAnotherFile.js
const socketInstance = require('./socket.instance').socketInstance;
socketInstance.newSocket.subscribe(socket => {
    socket.on('test', console.log);
});

It's only basic example how to share your socket server instance between any other classes/files in your code. Everything depends on your needs

And on frontend situation is somewhat similar

Upvotes: 4

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