Isauthenticated() always returns false in express-passport

See more:

authentication

AngularJs

Express

The req.isAuthenticated() function of api.js always returns false regardless whether the user is logged in or not. This particular function doesn't seem to work.
I don't know what to do. I am stuck on this for a long time.

Any help is highly appreciated.

I am testing my code on advanced rest client.

app.js (main file):

var http_errors = require('http-errors');
    var express = require('express');
    var path = require('path');
    var favicon = require('serve-favicon');
    var logger = require('morgan');
    var passport = require('passport');
    var session = require('express-session');
    var cookieParser = require('cookie-parser');
    var bodyParser = require('body-parser');
    
    var api = require('./routes/api');
    var authenticate = require('./routes/authenticate')(passport);
    
    var app = express();
    
    app.use(cookieParser('super duper secret'));
    app.use(session({
        secret: 'super duper secret',
        resave: true,
        saveUninitialized: true
    }));
    app.use(logger('dev'));
    app.use(bodyParser.json());
    app.use(bodyParser.urlencoded({ extended: false }));
    app.use(express.static(path.join(__dirname, 'public')));
    app.use(passport.initialize());
    app.use(passport.session());
    
    // view engine setup
    app.set('views', path.join(__dirname, 'views'));
    app.set('view engine', 'ejs');
    
    app.use('/api', api);
    app.use('/auth', authenticate);
    
    //Initialize passport
    var initPassport = require('./passport-init');
    initPassport(passport);
    
    module.exports = app;

Routing files:-

api.js:

var express = require('express');
    var router = express.Router();
    
    router.use(function(req, res, next){
        
        if(req.method === "GET"){
            //continue to the next middleware or request handler
            return next();
        }
        
        if (!req.isAuthenticated()){
            //user not authenticated, redirect to login page
            return res.redirect('/#login');
        }
        
        //user authenticated continue to next middleware or handler
        return next();
    });
    
    //api for all posts
    router.route('/posts')
    
        //returns all posts
        .get(function(req, res){
        
            //temporary solution
            res.send({message: 'TODO return all posts'});
        })
    
        //posts all posts
        .post(function(req, res){
        
            //temporary solution
            res.send({message: 'TODO create a new post'});
        })
    
    module.exports = router;

authenticate.js:

var express = require('express');
    var router = express.Router();
    
    module.exports = function(passport){
    
    	//sends successful login state back to angular
    	router.get('/success', function(req, res){
    		res.send({state: 'success', user: req.user ? req.user : null});
    	})
    
    	//sends failure login state back to angular
    	router.get('/failure', function(req, res){
    		res.send({state: 'failure', user: null, message: "Invalid username or password"});
    	})
    
    	//log in
    	router.post('/login', passport.authenticate('login', {
    		successRedirect: '/auth/success',
    		failureRedirect: '/auth/failure'
    	}))
    
    	//sign up
    	router.post('/signup', passport.authenticate('signup', {
    		successRedirect: '/auth/success',
    		failureRedirect: '/auth/failure'
    	}))
    
    	//log out
    	router.get('/signout', function(req, res) {
    		req.logout();
    		res.redirect('/');
    	});
    
    	return router;
    }

passport-init.js (file that exploits passport module):

var LocalStrategy   = require('passport-local').Strategy;
    var bCrypt = require('bcrypt-nodejs');
    //temporary data store
    var users = {};
    module.exports = function(passport){
    
    	// Passport needs to be able to serialize and deserialize users to support persistent login sessions
    	passport.serializeUser(function(user, done) {
            
            //tell passport which id to use for user
    		console.log('serializing user:',user.username)
    		return done(null, user.username);
    	})
    
    	passport.deserializeUser(function(username, done) {
            User.findById(username, function(err, user){
    		return done(err,users[username]);
            })
    	})
    
    	passport.use('login', new LocalStrategy({
    			passReqToCallback : true
    		},
    		function(req, username, password, done) { 
    
                if(!users[username]){
                    return done('user not found',false);
                }
            
                if(!isValidPassword (users[username],password)){
                    return done('invalid password', false);
                }
            
                console.log('sucessfully logged in')
    			return done(null, users[username]);
    		}
    	))
    
    	passport.use('signup', new LocalStrategy({
    			passReqToCallback : true // allows us to pass back the entire request to the callback
    		},
    		function(req, username, password, done) {
            
                if(users[username]){
                    return done('username already taken', false);
                }
                
                users[username] = {
    				username: username,
    				password: createHash(password)
    			}
            
                console.log('sucessfully signed in')
                console.log(users[username])
    			return done(null, users[username]);
    		}
    	))
    
        var isValidPassword = function(user, password){
    		return bCrypt.compareSync(password, user.password);
    	}
        
    	var createHash = function(password){
    		return bCrypt.hashSync(password, bCrypt.genSaltSync(10), null);
    	}
    };

What I have tried:

I tried many solutions like adding cookies (which as far as I gathered from other forums is the reason why req.isAuthenticated() doesn't work), explicitly calling logIn (though passport.authenticate in authenticate.js calls it by default) and some other small remedies like changing the order of my middlewares but nothing is working.