server.js

/**
 * server.js
 * 	- set up an Express.js server	
 * 	- load config file (depends on the environment)
 * 	- connect to mongoDB
 * 	- configure various middleware
 * 	- load controllers & helpers
 */
var express = require('express'),
	fs = require('fs'),
	Db = require('mongodb').Db,
	Server = require('mongodb').Server,
	connect = require('connect'),
	mongoStore = require('connect-mongodb');
	url = require('url');

// express server
var app = express.createServer();
app.root = __dirname;

// Load config file
app.config = require(app.root + '/config/' + app.set('env') + '.js');

// Database Connect to mongo

var mongo_hq = url.parse(process.env.MONGOHQ_URL || app.config.database.url);
console.log('mongo_hq - ' + mongo_hq);
var mongo_auth = mongo_hq.auth ? mongo_hq.auth.split(":") : '';
console.log('mongo_auth - ' + mongo_auth );
var mongo_db_username = mongo_auth[0] || '';
console.log('mongo_db_username - ' + mongo_db_username);
var mongo_db_password = mongo_auth[1] || '';
console.log('mongo_db_password - ' + mongo_db_password);

app.db = new Db(mongo_hq.pathname.replace('/',''), 
				new Server(mongo_hq.hostname, mongo_hq.port, app.config.database.options)
				//new Server(app.config.database.host, app.config.database.port, app.config.database.options)
			);
console.log("Connecting to MongoDB...");

app.db.open(function(err, db_conn) {
	
	// Don't start without MongoDB running
	if(err) {
		console.log(err);
		return;
	}
	
	db_conn.authenticate(mongo_db_username,mongo_db_password,{},function(err,success){

		if (err) {
            console.warn("MONGO ERROR: unauthorized "+ err.message);
        } else {

			// Middleware setup
			app.use(express.logger());				// Enable request logging	
			app.use(express.bodyParser());		// parses urlencoded request bodies which populates req.body
			app.use(express.methodOverride());	// sets a hidden input of _method to an arbitrary HTTP method 
			app.use(express.cookieParser());	// Required by session
			
			// Use connect-mongodb SessionStore
			app.use( connect.session({
				cookie: {maxAge: 60000 * 20}, // 20 minutes
				secret: app.config.sessions.secret,
				store: new mongoStore({db: app.db})
				})
			);
			
			// User model
			User = require(app.root + '/lib/user').init(app.db);
			
			// Authentication => populate req.current_user
			app.use(
				(function() {
					return function(req, res, next) {
						User.authenticate(req, res, function(current_user) {
							req.current_user = current_user;
							next();
						}, function() {
						    next();
						});
					};
				})()
			);
			
			app.dynamicHelpers({
				 // req.flash to html helper
				 messages: function(req, res){
				    return function(){
				        var buf = [],
				            messages = req.flash(),
				            types = Object.keys(messages),
				            len = types.length;
				        if (!len) {
				           return '';
			           }
				        buf.push('<div id="messages">');
				        for (var i = 0 ; i < len; ++i) {
				            var type = types[i],
				                msgs = messages[type], j;
				            buf.push('  <ul class="' + type + '">');
				            for (j = 0, len = msgs.length; j < len; ++j) {
				                var msg = msgs[j];
				                buf.push('    <li>' + msg + '</li>');
				            }
				            buf.push('  </ul>');
				        }
				        buf.push('</div>');
				        return buf.join('\n');
				    };
				},
				current_user: function(req, res){
					return req.current_user;
				}
			});
			
			app.use(app.router);
			app.use(express["static"](app.root + '/public'));
			
			app.set('views', app.root + '/lib/views');
			app.set('view engine', 'ejs');
			
			app.error(function(err, req, res, next){
				if (err.message == "Unauthorized") {
					res.render('401', { status: 401, locals: {	title: 'Unauthorized', action: 'error', error: err }});
				}
				else {
					res.render('500', { status: 500, locals: {	title: 'Error', action: 'error', error: err }});
				}
			});
			
			
			// Middleware for authentication checking
			app.require_login = function(req, res, next) {
				(!!req.current_user) ? next() : next(new Error('Unauthorized'));
			};
			
			// Require all helpers & controllers
			var loadDirs = ['helpers', 'controllers'];
			loadDirs.forEach(function(dir) {
				fs.readdirSync(app.root + '/lib/'+dir+'/').forEach(function(file) {
					// test if JS file
					if(file.substr(-3) == ".js") {
						require(app.root + '/lib/'+dir+'/'+file).expressRoutes(app);
					}
				});
			});
			
			// Catch all other routes
			app.use(function(req,res) { 
				res.render('404', { status: 404, locals: {	title: 'NotFound', action: 'error' }});
			} );

			// start the server
			var server_port = process.env.DEFAULT_PORT || process.env.PORT || app.config.server.port;
			var server_host = process.env.DEFAULT_HOST || app.config.server.host;
			app.listen(server_port, server_host, function() {
    			console.log('Listening on port %d', server_port);
			});
			
			console.log("App started in '"+app.set('env')+"' environment !\n" +
							"Listening on http://"+app.config.server.host+":"+app.config.server.port);

			// Intercept exceptions after init so that the server doesn't crash at each uncatched exception
			process.on('uncaughtException', function (err) {
				console.log('Caught exception: ' + err);
				console.log(err.stack);
			});
		}
			
	});
});