Question

I’m trying an example of WebSocket to develop a simple chat.

server.js:

var app = require('http').createServer(handler)
, io = require('socket.io').listen(app)
, fs = require('fs')

app.listen(8080);

function handler (req, res) {
   fs.readFile(__dirname + '/test.html',
   function (err, data) {
      if (err) {
        res.writeHead(500);
        return res.end('Error loading index.html');
      }

    res.writeHead(200);
    res.end(data);
  });
}

and test.html:

<script src="/socket.io/socket.io.js"></script>
<script>
 var socket = io.connect('http://localhost');

 socket.on('connect', function() {
  alert('<li>Connected to the server.</li>');
 });

 socket.on('message', function(message) {
    alert(message);
 });

 socket.on('disconnect', function() {
   alert('<li>Disconnected from the server.</li>');
 });

 function sendF(){
    var message = "Test";
    socket.send(message);
    alert('Test Send');     
}

In test.html I have also a simple button that onClick call sendF.

If I try it I see on my browser an alert when I CONNECT, SEND, and DISCONNCT, and if I check in console, I see the message.

But I cannot receive the same message in response from server, to show it in my browser! I think socket.on('message'... is not working for me!

Answer 1

Your server.js is missing event listeners. It’s also missing where you are doing the send of the message to be displayed in the browser.

io.sockets.on('connection', function (socket) {
  console.log('user connected');
  socket.send('hello world');
  socket.on('disconnect', function () {
    console.log('user disconnected.');
  });
  socket.on('message', function (data) {
    console.log(data);
  });
});