title: webSocketServer node.js how to differentiate clients
body: <p>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:</p>
  
  <pre><code>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');
  });
  </code></pre>
  
  <p>This code works fine with my client js.</p>
  
  <p>But I would like to send a message to a particular user or all users having sockets open on my server.</p>
  
  <p>In my case I send a message as a client and I receive a response but the others user show nothing.</p>
  
  <p>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.</p>