Middleware not redirect

I'm writing a simple system to control authentication for users, only registered users have access to the site. If you are not authenticated redirect you to the login page.

Quite simply I'm using a middleware to make this control.

My problem is that when the condition for the redirection is valid, this does not happen!

// Routes
module.exports = function(app) {
app.use(function(req, res, next) {
    console.log(req.url);

    if (typeof(res.session) == 'undefined' && req.url != '/users/login') {
        console.log('redirect');
        res.redirect('/users/login');
    } else {
        console.log('no redirect');
        next();
    }
});

app.get('/',                    routes.site.index);

app.all('/users/login',         routes.user.login);
};

Obviously, the stout console is:

/
redirect
/users/login
no redirect

And the page is loading indefinitely...

Any suggestions?

Thanks!

PS: I apologize if I misspelled, Google helped me!

@-------------------- EDIT:

I opted to use Passport for the management of Auth.

I only have one problem, I run the routes of my app in a separate file.

app.js

// Auth
var passport = require('passport'), strategy = require('passport-local').Strategy;
passport.use(new strategy(function(username, password, done) {
var user = require('./db')('user');

user.findOne({username: username}, function(err, user) {
    if (err) return done(err);
    if (!user) return done(null, false);
    if (!user.validPassword(password)) return done(null, false);

    return done(null, user);
});
}));
passport.serializeUser(function(user, done) {
done(null, user.id);
});
passport.deserializeUser(function(id, done) {
var user = require('./db')('user');

user.findOne(id, function(err, user) {
    done(err, user);
});
});
// End Auth

require('./routes')(app, passport);

app.configure(function(){
  app.set('port', process.env.PORT || 3000);
  app.set('views', __dirname + '/views');
  app.set('view engine', 'jade');
  app.use(express.favicon());
  app.use(express.logger('dev'));
  app.use(express.bodyParser());
  app.use(passport.initialize());
  app.use(passport.session());
  app.use(express.methodOverride());
  app.use(app.router);
  app.use(express.static(__dirname + '/public'));
});

routes/index.js

// Routes
module.exports = function(app, passport) {
    app.get('/', passport.authenticate('local', {successRedirect: '/', failureRedirect: '/login' }), routes.site.index);

    app.all('/login', routes.user.login);
};

routes/user.js

exports.login = function(req, res, next) {
    switch (req.method) {
        default:
        case 'GET':
            res.render('user/login', {title: 'Login'});
        break;
        case 'POST':
            /*passport.authenticate('local', function(err, user, info) {
                res.json([user, info]);
            });
            */
        break;
    }
};

The redirect to the login page works fine, but I would manage the routes in different files, and so I can not help maintain the variable passport to be able to handle the callback control in the file user.js.

Ideas? Thanks!!!