Nodejs+Expressjs+SocketIO on Heroku gives GET /socket.io/?EIO... 404 - node.js

Question

I am having problem with setting socketIO 1.1 up to work on Heroku. I'm running Express v4.2. The socketio runs perfectly on localhost. However, on Heroku, it gives this error:
From Heroku log:
2014-09-15T09:40:14.578660+00:00 app[web.1]: GET /socket.io/?EIO=3&transport=polling&t=1410774014583-86 404 6ms - 744b
From browser:
GET http://[mydomainname]/socket.io/?EIO=3&transport=polling&t=1410774080589-97 404 (Not Found) socket.io.js:2680Request.create socket.io.js:2680Request socket.io.js:2614XHR.request socket.io.js:2555XHR.doPoll socket.io.js:2585Polling.poll socket.io.js:2951Polling.doOpen socket.io.js:2895Transport.open socket.io.js:2106Socket.open socket.io.js:1580Socket socket.io.js:1467Socket socket.io.js:1419Manager.open.Manager.connect socket.io.js:272(anonymous function)
I have followed the recommended configurations in Socket IO documentations. Relevant code as follows:
var express = require('express');
/* routes */
var routes = require('./routes/index');
var users = require('./routes/users');
var path = require('path');
var favicon = require('static-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var cons = require('consolidate');
var app = express();
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.engine('dust', cons.dust);
app.set('view engine', 'dust');
app.use(favicon());
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded());
app.use(cookieParser('hashionhashion'));
app.use(require('less-middleware')(path.join(__dirname, 'public')));
app.use(express.static(path.join(__dirname, 'public')));
//routing
app.use('/', routes);
app.use('/users', users);
/// catch 404 and forward to error handler
app.use(function(req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(err);
});
/// error handlers
// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: err
});
});
}
// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: {}
});
});
//start the server
var server = require('http').Server(app);
var io = require('socket.io').listen(server);
var ioSockets = {};
io.on('connection', function(socket) {
ioSockets[socket.id] = socket;
socket.emit('welcome', {message: socket.id});
socket.on('disconnect', function(socket) {
delete ioSockets[socket.id];
});
});
exports.ioSockets = ioSockets;
module.exports = app;
server.listen(3000, function() {
console.log('Congrats, nothing broke!! Listening on port %d', server.address().port);
});
In my client file, the script are as follows:
<script src="my_path_to/socket.io.js"></script>
<script>
var socket = io.connect();
var socketId = '';
socket.on('welcome', function (data) {
socketId = data.message;
});
</script>
I also tried io.connect to "http://localhost", "http://localhost:3000", and my Heroku app domain. All of them produces the same error.
Any help will be greatly appreciated!

Answer 1

The issue ends up to be a express one, which has since been corrected in versions after 4.10.0.
For your own reading:
https://github.com/strongloop/express/issues/2406
https://github.com/jshttp/on-finished/issues/10

Answer 2

Look like you change socket.io path. Because I saw src="my_path_to/socket.io.js". socket.io try to connect but got 404.
Is there a route of express handled '/socket.io/'?
Even you resolve the 404 error. You will hit the other error. Because currently on heroku you must set socket.io connect to a https address. Otherwise socket.io will work under polling.
More detail:
https://github.com/Automattic/engine.io/issues/261