passportConfig.js

// load all the things we need
var LocalStrategy = require('passport-local').Strategy;

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

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);
		});
	});

	// =========================================================================
	// LOCAL SIGNUP ============================================================
	// =========================================================================
	// we are using named strategies since we have one for login and one for signup
	// by default, if there was no name, it would just be called 'local'

	passport.use('local-signup', new LocalStrategy({
			usernameField : 'username',
			passwordField : 'password',
			passReqToCallback : true // allows us to pass back the entire request to the callback
		}, function(req, username, password, done) {

		// asynchronous
		// User.findOne wont fire unless data is sent back
		process.nextTick(function() {

			// find a user whose username is the same as the forms username
			// we are checking to see if the user trying to login already exists
			User.findOne({ 'username' :  username }, function(err, user) {
				// if there are any errors, return the error
				if (err)
					return done(err);

				// check to see if theres already a user with that username
				if (user) {
					return done(null, false, req.flash('signupMessage', 'That username is already taken.'));
				} else {

					// if there is no user with that username
					// create the user
					var newUser = new User();

					// set the user's local credentials
					newUser.username = username;
					newUser.password = newUser.generateHash(password);

					// save the user
					newUser.save(function(err) {
						if (err)
							throw err;
						return done(null, newUser);
					});
				}

			});    

		});

	}));

	// =========================================================================
    // LOCAL LOGIN =============================================================
    // =========================================================================
	// we are using named strategies since we have one for login and one for signup
	// by default, if there was no name, it would just be called 'local'

    passport.use('local-login', new LocalStrategy({
        usernameField : 'username',
        passwordField : 'password',
        passReqToCallback : true // allows us to pass back the entire request to the callback
	    },
	    function(req, username, password, done) { // callback with username and password from our form

			// find a user whose username is the same as the forms username
			// we are checking to see if the user trying to login already exists
        User.findOne({ 'username' :  username }, function(err, user) {
            // if there are any errors, return the error before anything else
            if (err)
                return done(err);

            // if no user is found, return the message
            if (!user)
                return done(null, false, req.flash('loginMessage', 'No user found.')); // req.flash is the way to set flashdata using connect-flash

			// if the user is found but the password is wrong
            if (!user.validPassword(password))
                return done(null, false, req.flash('loginMessage', 'Oops! Wrong password.')); // create the loginMessage and save it to session as flashdata

            // all is well, return successful user
            return done(null, user);
        });

    }));


};