app.js

var express =require('express'),
    app = express(),
	server = require('http').createServer(app),
	io = require('socket.io').listen(server),
	mongoose = require('mongoose'),
	users = {};
	
	
server.listen(80);

mongoose.connect('mongodb://localhost/m_chat',function(err){
	if(err){
		console.log(err);
	}else{
		console.log('Connected to mongodb');
	}
});

var chatSchema = mongoose.Schema({
	// name:{first:String,last:String},
	nick:String,
	msg:String,
	created:{type:Date,default:Date.now}
});

var Chat = mongoose.model('Message',chatSchema);


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

io.sockets.on('connection',function(socket){
	var query = Chat.find({});
	query.sort('-created').limit(8).exec(function(err,docs){
		if(err) throw err;
		console.log('sending old msgs');
		socket.emit('load old msgs',docs);	
	});
	socket.on('new user',function(data,callback){
		if(data in users){
			callback(false);
		}else{
			callback(true);
			socket.nickname = data;
			users[socket.nickname] = socket;
			updateNicknames();
		}
	});
	
	function updateNicknames(){
		io.sockets.emit('usernames',Object.keys(users));
	}
	
	socket.on('send message',function(data,callback){
		var msg = data.trim();
		if(msg.substr(0,3) === '/w '){
			msg = msg.substr(3);
			var ind = msg.indexOf(' ');
			if(ind !== -1){
				var name = msg.substring(0,ind);
				var msg = msg.substring(ind + 1);
				if(name in users){
					users[name].emit('whisper',{msg:msg,nick:socket.nickname});
					console.log('Whisper');
				}
				
			}else{
				callback('Error! Enter a message');
			}
			
		}else{
			var newMsg = new Chat({msg:msg,nick:socket.nickname});
			newMsg.save(function(err){
				if(err) throw err;
				io.sockets.emit('new message',{msg:msg,nick:socket.nickname});
			});
		}
	});
	
	socket.on('disconnect',function(data){
		if(!socket.nickname) return;
		delete users[socket.nickname];
		updateNicknames();
	});
});