Bridging a simple Node.js & Socket.io chat app wit

Question

I have a basic Node.js & Socket.io chat application running on Heroku that I want to integrate into my main rails website. I understand the way to do this is to have two separate Heroku apps - one for rails, one for Node.js.

It doesn't appear to be as simple as moving the client html from the node app to the rails app (giving it the other app's url in 'io.connect();').

The chat app server seems to automatically call the client index.html its own application, and not allow an external source to connect to it. Removing the code that does this (marked below) does not make it work.

I'm painfully new to Node.js & Socket.io and am hoping that this might be a relatively simple fix for a pro.

I believe the functionality I'm after here works in Liam Kaufman's excellent rails/node.js/socket.io example - his node.js server code is here: https://github.com/liamks/Chatty-Node-Server/blob/master/chat-server.js

I've tried mocking my app's code up to be like his, but haven't yet been able to make it work. He e.g. appears to use an 'http' server, whereas mine uses an 'express' server - I wondered if this might be relevant.

Any help would be greatly appreciated.

UPDATE: Ok, so a bizarre turn of events, thanks to redhotvengeance's reply below I've got this working - server is up on heroku and my client html and javascript connects to it. Great - code below. The problem is, however, that the client html file only connects when it's outside of the Rails app!! i.e. on my desktop!! The moment I put it in the rails application's public/ folder or in a view on my localhost, I get nothing! This makes no sense. I checked it wasn't because of any other random erroneous javascript in my asset pipeline conflicting by just creating a new rails app and dropping the html file in the public/ folder - again nothing - just a dead html page that doesn't connect. Does anyone have any idea what might be going on here? Does Rails have some security feature in place that stops connections to external servers or something??

UPDATE 2: I'm told this has something to do with the 'same origin policy', and I'm in trouble. Is there any way around it? Seems Liam didn't have this problem.

Client:

<script src="http://calm-sands-3826.herokuapp.com/socket.io/socket.io.js" type="text/javascript"></script>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
<script>
    var socket = io.connect('http://calm-sands-3826.herokuapp.com');

    // on connection to server, ask for user's name with an anonymous callback
    socket.on('connect', function(){
        // call the server-side function 'adduser' and send one parameter (value of prompt)
        socket.emit('adduser', prompt("What's your name?"));
    });

    // listener, whenever the server emits 'updatechat', this updates the chat body
    socket.on('updatelog', function (username, data) {
        $('#log').append('<b>'+username + ':</b> ' + data + '<br>');
    });

    // listener, whenever the server emits 'updateusers', this updates the username list
    socket.on('updateusers', function(data) {
        $('#users').empty();
        $.each(data, function(key, value) {
            $('#users').append('<div>' + key + '</div>');
        });
    });

</script>
<div style="float:left;width:100px;border-right:1px solid black;height:300px;padding:10px;overflow:scroll-y;">
    <b>USERS</b>
    <div id="users"></div>
</div>
<div style="float:left;width:300px;height:250px;overflow:scroll-y;padding:10px;">
    <div id="log"></div>
</div>

Server:

var port = process.env.PORT || 5001;

var io = require('socket.io').listen(parseInt(port));

io.configure(function(){
  io.set("transports", ["xhr-polling"]); 
  io.set("polling duration", 10); 
  io.set("close timeout", 10);
  io.set("log level", 1);
})

// usernames which are currently connected to the chat
var usernames = {};

io.sockets.on('connection', function (socket) {

    // when the client emits 'adduser', this listens and executes
    socket.on('adduser', function(username){
        // we store the username in the socket session for this client
        socket.username = username;
        // add the client's username to the global list
        usernames[username] = username;
        // echo to client they've connected
        socket.emit('updatelog', 'SERVER', 'you have connected');
        // echo globally (all clients) that a person has connected
        socket.broadcast.emit('updatelog', 'SERVER', username + ' has connected');
        // update the list of users in chat, client-side
        io.sockets.emit('updateusers', usernames);
    });

    // when the user disconnects.. perform this
    socket.on('disconnect', function(){
        // remove the username from global usernames list
        delete usernames[socket.username];
        // update list of users in chat, client-side
        io.sockets.emit('updateusers', usernames);
        // echo globally that this client has left
        socket.broadcast.emit('updatelog', 'SERVER', socket.username + ' has disconnected');
    });
});

Answer 1

If what you're trying to do is connect pages in your Rails app to your seperate Node.js app running socket.io, then skip setting up Express entirely. You're not looking to actually serve pages from your Node app, just connect users to the socket.io server.

Let's say your Node.js app on Heroku is called: my-awesome-socket-app.

my-awesome-socket-app:

var io = require('socket.io').listen(parseInt(process.env.PORT));

io.configure(function () { 
  io.set("transports", ["xhr-polling"]); 
  io.set("polling duration", 10); 
});

io.sockets.on('connection', function (socket) {
  socket.on('disconnect', function () {
    io.sockets.emit('user disconnected');
  });
});

Then, in the Rails pages you want to connect to the socket.io server:

<script src="http://my-awesome-socket-app.herokuapp.com/socket.io/socket.io.js"></script>
<script>
  var socket = io.connect('http://my-awesome-socket-app.herokuapp.com');
  socket.on('connect', function (data) {
    console.log('connected!');
  });
</script>