server.js

var express = require('express'),
	fs = require('fs'),
	path = require('path'),
	jQuery = require('jquery'),
	Tuiter = require('tuiter'),
	app = module.exports = express.createServer();

/*
* Configurations
*/

app.configure(function(){
    app.use(express.bodyParser());
    app.use(express.methodOverride());
    app.use(app.router);
    app.use(express.static(__dirname + '/public'));
    app.use(express.logger(':remote-addr - :method :url HTTP/:http-version :status :res[content-length] - :response-time ms'));
    app.use(express.favicon());
});

app.configure('development', function(){
    app.use(express.errorHandler({ dumpExceptions: true, showStack: true }));
});

app.configure('production', function(){
    app.use(express.errorHandler());
});

/*
* Express
*/

function secondsToString(seconds) {
	var numDays = Math.floor(seconds / 86400);
	var numHours = Math.floor((seconds % 86400) / 3600);
	var numMinutes = Math.floor(((seconds % 86400) % 3600) / 60);
	var numSeconds = Math.floor((seconds % 86400) % 3600) % 60;

	return numDays +" days "+ numHours +" hours "+ numMinutes +" minutes "+ numSeconds +" seconds.";
}

app.get('/', function(req, res) {
	res.sendfile('index.html');
});

app.get('/uptime', function(req, res) {
	res.end("The server has been up for: "+ secondsToString( process.uptime().toString() ) );
});

app.get('/restart', function(req, res) {
	console.log(" * Restarting in 5 seconds...");
	setTimeout(function() {
		if (stream !== '') {
			restartTwitterFeed();
		}
		res.redirect('/');
	}, 5000);
});

/*
* Main
*/

var	totUsers = 0;

var stream = '',
	streamInterval = '',
	configs = '';

app.listen(8080);
console.log("* Express server listening in %s mode", app.settings.env);

configs = readConfigs();
console.log("* Param: "+ configs.param +", value: "+ configs.value);

streamInterval = setInterval(function() {
	if (stream !== '') {
		restartTwitterFeed();
		console.log("* Stream autorestarted after 5 minutes");
	}
}, 300000); // 5 mins

/*
* Functions
*/

// return require("./filename-with-no-extension"); could be used
function readJSONFile(filename) {
	var JSONFile = "";

	try {
		JSONFile = JSON.parse(fs.readFileSync(__dirname +'/'+ filename, 'utf8'));
	} catch(e) {
		console.log("Error while reading "+ filename +": "+ e);
	}

	return JSONFile;
}

function writeJSONFile(filename, contents) {
	try {
		fs.writeFileSync(__dirname +'/'+ filename, JSON.stringify(contents), 'utf8');
	} catch(e) {
		console.log("Error while writing "+ filename +": "+ e);
	}
}

function readConfigs() {
	var twitterConfigs = readJSONFile("./configs/twitter.json"),
		paramsConfigs = readJSONFile("./configs/params.json");

	return {
		twitterApp : twitterConfigs,
		param : paramsConfigs.param,
		value : paramsConfigs.value
	};
}

function strencode(data) {
  return unescape(encodeURIComponent(JSON.stringify(data)));
}

function restartTwitterFeed() {
	stream = '';
	grabTwitterFeed();
	console.log("* Stream restarted");
}

// Using Twitter Streaming API
function grabTwitterFeed() {
	stream = new Tuiter({
		"consumer_key" : configs.twitterApp.consumer_key,
		"consumer_secret" : configs.twitterApp.consumer_secret,
		"access_token_key" : configs.twitterApp.access_token_key,
		"access_token_secret" : configs.twitterApp.access_token_secret
	});

	stream.filter({ track: configs.value.split(",") }, function(feed) {

		console.log("* Stream started");

		feed.on('tweet', function(tweet) {
			io.sockets.emit("tweet", strencode(tweet));
		});

		feed.on('delete', function(del) {
			console.log("Deleted: "+ del);
		});

		feed.on('error', function(stream_err) {
			var line = "";
			console.log("Stream ERR: "+ stream_err);

			line = new Date().toJSON() +" "+ stream_err;
			fs.open(path.join(__dirname, 'errors.log'), 'a', 0666, function(err, fd) {
				fs.write(fd, line, null, undefined, function (err, written) {
					// console.log(written +"B written.");

					fs.close(fd);
				});

			});

		});
	});
}

/*
* Socket.io
*/

var io = require('socket.io').listen(app);

io.configure(function() {
	io.enable('browser client minification');
	io.set('log level', 1);
});

io.sockets.on('connection', function(client) {
	totUsers++;
	console.log('+ User '+ client.id +' connected, total users: '+ totUsers);

	if ((totUsers > 0) && (stream === '')) {
		grabTwitterFeed();
	}

	client.emit("clientId", { id: client.id });
	client.emit("filters", { param: configs.param, value: configs.value });
	io.sockets.emit("tot", { tot: totUsers });

	client.on('search', function(data) {
		configs.value = data.search;
		console.log("> Received new search param: "+ data.search);

		restartTwitterFeed();

		io.sockets.emit("filters", { param: configs.param, value: configs.value });
	});

	client.on('disconnect', function() {
		totUsers--;
		console.log('- User '+ client.id +' disconnected, total users: '+ totUsers);

		if (totUsers === 0) {
			stream = '';
		}

		io.sockets.emit("tot", { tot: totUsers });
	});
});