I am trying to use sockets with node.js, I succeded but I don't know how to differentiate clients in my code. The part concerning sockets is this:

var WebSocketServer = require('ws').Server, 
    wss = new WebSocketServer({port: 8080});
wss.on('connection', function(ws) {
    ws.on('message', function(message) {
        console.log('received: %s', message); 
        ws.send(message);
    });
    ws.send('something');
});

This code works fine with my client js.

But I would like to send a message to a particular user or all users having sockets open on my server.

In my case I send a message as a client and I receive a response but the others user show nothing.

I would like for example user1 sends a message to the server via webSocket and I send a notification to user2 who has his socket open.