index.js

var express = require('express');
var app = express();
var server = require('http').createServer(app);
var io = require('socket.io')(server);
var port = process.env.PORT || 3000;


 var passport          =     require('passport')
  , util              =     require('util')
  , FacebookStrategy  =     require('passport-facebook').Strategy
  , session           =     require('express-session')
  , cookieParser      =     require('cookie-parser')
  , bodyParser        =     require('body-parser')
  , config            =     require('./configuration/config')
  , mysql             =     require('mysql');

//Define MySQL parameter in Config.js file.
var connection = mysql.createConnection({
  host     : config.host,
  user     : config.username,
  password : config.password,
  database : config.database
});

//Connect to Database only if Config.js parameter is set.

if(config.use_database==='true')
{
    connection.connect();
}

// Passport session setup.
passport.serializeUser(function(user, done) {
  done(null, user);
});

passport.deserializeUser(function(obj, done) {
  done(null, obj);
});


// Use the FacebookStrategy within Passport.

passport.use(new FacebookStrategy({
    clientID: config.facebook_api_key,
    clientSecret:config.facebook_api_secret ,
    callbackURL: config.callback_url
  },
  function(accessToken, refreshToken, profile, done) {
    process.nextTick(function () {
      //Check whether the User exists or not using profile.id
      if(config.use_database==='true')
      {
      connection.query("SELECT * from user_info where user_id="+profile.id,function(err,rows,fields){
        if(err) throw err;
        if(rows.length===0)
          {
            console.log("There is no such user, adding now");
            connection.query("INSERT into user_info(user_id,user_name) VALUES('"+profile.id+"','"+profile.username+"')");
          }
          else
            {
              console.log("User already exists in database");
            }
          });
      }
      return done(null, profile);
    });
  }
));


//app.set('views', __dirname + '/views');
app.set('view engine', 'ejs');
app.use(cookieParser());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(session({ secret: 'keyboard cat', key: 'sid'}));
app.use(passport.initialize());
app.use(passport.session());
app.use(express.static(__dirname + '/public'));

app.get('/', function(req, res){
  res.render('index', { user: req.user });
});

app.get('/index1', function(req, res){
  res.render('index1', { user: req.user });
});

app.get('/account', ensureAuthenticated, function(req, res){
  res.render('account', { user: req.user });
});

app.get('/auth/facebook', passport.authenticate('facebook',{scope:'email'}));


app.get('/auth/facebook/callback',
  passport.authenticate('facebook', { successRedirect : '/index1', failureRedirect: '/login' }),
  function(req, res) {
    res.redirect('/');
  });

app.get('/logout', function(req, res){
  req.logout();
  res.redirect('/');
});


function ensureAuthenticated(req, res, next) {
  if (req.isAuthenticated()) { return next(); }
  res.redirect('/login')
}
server.listen(port, function () {
  console.log('Server listening at port %d', port);
});
app.use(express.static(__dirname + '/public'));
var usernames = {};
var numUsers = 0; 

io.on('connection', function (socket) {
  var addedUser = false;
  socket.on('new message', function (data) {
    socket.broadcast.emit('new message', {
      username: socket.username,
      message: data
    });
  });
  socket.on('add user', function (username) {
    socket.username = username;
    usernames[username] = username;
    ++numUsers;
    addedUser = true;
    socket.emit('login', {
      numUsers: numUsers
    });
    socket.broadcast.emit('user joined', {
      username: socket.username,
      numUsers: numUsers
    });
  });
  socket.on('typing', function () {
    socket.broadcast.emit('typing', {
      username: socket.username
    });
  });
  socket.on('stop typing', function () {
    socket.broadcast.emit('stop typing', {
      username: socket.username
    });
  });
  socket.on('disconnect', function () {
    
    if (addedUser) {
      delete usernames[socket.username];
      --numUsers;
      socket.broadcast.emit('user left', {
        username: socket.username,
        numUsers: numUsers
      });
    }
  
  });
});