title: How to best structure an Express V4.11+ project with Socket.IO?
body: <p>I've used the latest version of the <b>express-generator</b> (<a href="http://expressjs.com/starter/generator.html">link</a>) to generate a boilerplate <b>Express 4.11.2</b> project.</p>
  
  <p>I'm trying to figure out the best way of setting up <b>Socket.IO 1.3.3</b> with the changes that have been made a few major versions back in the Express framework, where the http server was moved into its own <code>bin/www</code> file.</p>
  
  <p>I'm getting confused because it seems like I need the express server in <code>app.js</code>, before it gets exported to <code>bin/www</code>.</p>
  
  <p>I've tried Googling for a few hours now and come up with nothing, it seems that the Express framework is moving so fast that all of the previous articles are outdated.</p>
  
  <p>Any help would be greatly appreciated!</p>
  
  <p>I've included the two files in question below so you can see what I'm working with after generating the boilerplate express project.</p>
  
  <h3>bin/www</h3>
  
  <pre><code>#!/usr/bin/env node
  
  /**
   * Module dependencies.
   */
  
  var app = require('../app');
  var debug = require('debug')('Express-Socket:server');
  var http = require('http');
  
  /**
   * Get port from environment and store in Express.
   */
  
  var port = normalizePort(process.env.PORT || '3000');
  app.set('port', port);
  
  /**
   * Create HTTP server.
   */
  
  var server = http.createServer(app);
  
  /**
   * Listen on provided port, on all network interfaces.
   */
  
  server.listen(port);
  server.on('error', onError);
  server.on('listening', onListening);
  
  /**
   * Normalize a port into a number, string, or false.
   */
  
  function normalizePort(val) {
    var port = parseInt(val, 10);
  
    if (isNaN(port)) {
      // named pipe
      return val;
    }
  
    if (port &gt;= 0) {
      // port number
      return port;
    }
  
    return false;
  }
  
  /**
   * Event listener for HTTP server "error" event.
   */
  
  function onError(error) {
    if (error.syscall !== 'listen') {
      throw error;
    }
  
    var bind = typeof port === 'string'
      ? 'Pipe ' + port
      : 'Port ' + port
  
    // handle specific listen errors with friendly messages
    switch (error.code) {
      case 'EACCES':
        console.error(bind + ' requires elevated privileges');
        process.exit(1);
        break;
      case 'EADDRINUSE':
        console.error(bind + ' is already in use');
        process.exit(1);
        break;
      default:
        throw error;
    }
  }
  
  /**
   * Event listener for HTTP server "listening" event.
   */
  
  function onListening() {
    var addr = server.address();
    var bind = typeof addr === 'string'
      ? 'pipe ' + addr
      : 'port ' + addr.port;
    debug('Listening on ' + bind);
  }
  </code></pre>
  
  <h3>app.js</h3>
  
  <pre><code>var express = require('express');
  var path = require('path');
  var favicon = require('serve-favicon');
  var logger = require('morgan');
  var cookieParser = require('cookie-parser');
  var bodyParser = require('body-parser');
  
  var routes = require('./routes/index');
  var users = require('./routes/users');
  
  var app = express();
  
  // view engine setup
  app.set('views', path.join(__dirname, 'views'));
  app.set('view engine', 'ejs');
  
  // uncomment after placing your favicon in /public
  //app.use(favicon(__dirname + '/public/favicon.ico'));
  app.use(logger('dev'));
  app.use(bodyParser.json());
  app.use(bodyParser.urlencoded({ extended: false }));
  app.use(cookieParser());
  app.use(express.static(path.join(__dirname, 'public')));
  
  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: {}
      });
  });
  
  
  module.exports = app;
  </code></pre>