WebSocket (socket.io) proxy for Twitter stream (Twit).

twitter.js

// var server …
// …

var io   = require('socket.io').listen(server),
    Twit = require('twit');
var twitter = new Twit({ … });

io.sockets.on('connection', function connect( socket )
{
	function emitTweets( sn , tweets )
	{
		console.log('\n','tweets retrieved for '+sn, '\n');
		var data = [];
		for ( var i = tweets.length-1; i >= 0; i-- )
		{
			var tweet = tweets[i];
			data[i] = {
				"avatar": tweet.user.profile_image_url,
				"created": tweet.created_at,
				"id": tweet.id_str,
				"screen_name": tweet.user.screen_name,
				"text": tweet.text
			};
		}
		console.log('\n','Tweets: ', data, '\n');
		io.sockets.in( sn ).emit('tweets', data );
	}
	function verifyScreenName( sn )
	{
		if ( !sn )
		{
			socket.emit('error',
				{
					"statusCode": 404,
					"message": "A request was received but no screen name was specified."
				}
			);
			return false;
		}
		if ( (/\W/).test( sn ) )
		{
			socket.emit('error',
				{
					"statusCode": 400,
					"message": "The specified twitter screen name contains illegal characters: "+screen_name.match(/\W/).join('')
				}
			);
			return false;
		}

		return true;
	}
	// var tweetStream;

	socket.on('subscribe', function subscribe( data )
	{
		var sn = data.screen_name;
		if ( !verifyScreenName( sn ) ) return false;

		socket.join( sn );

		twitter.get('statuses/user_timeline', { "screen_name": sn }, function getTweets( err , tweets )
		{
			if ( err )
			{
				console.log( '\n' , 'userLookup.err: ', err, '\n' );
				socket.emit('error', { "statusCode": err.statusCode, "message": err.message });
				return false;
			} else
			{
				emitTweets( sn , tweets );
				var user_id = tweets[0].user.id;

				try {
					var tweetStream = twitter.stream('statuses/filter', { "follow": user_id });
					console.log('\ntweetStream: ', tweetStream, '\n');

					tweetStream.on('tweet', function onTweet(tweet)
					{	// emitTweets expects more than one; since there's only 1, wrap in array.
						console.log( '\ntweetStream -> new tweet: ', tweet, '\n' )
						emitTweets( sn , [tweet] );
					});
				} catch(err)
				{
					console.log('\ntweetStream error: ', tweetStream, '\n');
				}
			}
		});
	});

	socket.on('unsubscribe disconnect', function( data )
	{
		var sn = data.screen_name;
		if ( !verifyScreenName( sn ) ) return false;

		socket.leave( sn );
		if ( ! '/'+sn in io.sockets.manager.rooms ) tweetStream.stop();
	});
});