passport.js

var FacebookStrategy = require('passport-facebook').Strategy;

// load up the user model
var mongoose = require('mongoose');
var User = mongoose.model('User');

// load the auth variables
var config = require('./config');

// expose this function to our app using module.exports
module.exports = function(passport) {

	// =========================================================================
    // passport session setup ==================================================
    // =========================================================================
    // required for persistent login sessions
    // passport needs ability to serialize and unserialize users out of session

    // used to serialize the user for the session
    passport.serializeUser(function(user, done) {
        done(null, user.id);
    });

    // used to deserialize the user
    passport.deserializeUser(function(id, done) {
        User.findById(id, function(err, user) {
            done(err, user);
        });
    });

    // =========================================================================
    // FACEBOOK ================================================================
    // =========================================================================
    passport.use(new FacebookStrategy({

        // pull in our app id and secret from our auth.js file
        clientID        : config.facebookAuth.clientID,
        clientSecret    : config.facebookAuth.clientSecret,
        callbackURL     : config.facebookAuth.callbackURL,
        profileFields: ['id', 'displayName', 'photos', 'email']

    },

    // facebook will send back the token and profile
    function(token, refreshToken, profile, done) {

        // asynchronous
        process.nextTick(function() {

            // find the user in the database based on their facebook id
            User.findOne({ 'facebook.id' : profile.id }, function(err, user) {

                // if there is an error, stop everything and return that
                // ie an error connecting to the database
                if (err)
                    return done(err);

                // if the user is found, then log them in
                if (user) {
                    return done(null, user); // user found, return that user
                } else {
                    // if there is no user found with that facebook id, create them
                    var newUser            = new User();

                    console.log(profile);
                    console.log("token:" + token);
                    // set all of the facebook information in our user model
                    newUser.facebook.id    = profile.id; // set the users facebook id
                    newUser.facebook.token = token; // we will save the token that facebook provides to the user
                    newUser.facebook.name = profile.displayName;
                    //newUser.facebook.name  = profile.name.givenName + ' ' + profile.name.familyName; // look at the passport user profile to see how names are returned
                    newUser.facebook.email = profile.emails[0].value; // facebook can return multiple emails so we'll take the first

                    // save our user to the database
                    newUser.save(function(err) {
                        if (err)
                            throw err;

                        // if successful, return the new user
                        return done(null, newUser);
                    });
                }
            });
        });
    }));
};