Redirecting to previous page after authentication in node.js using passport.js

Question

I'm trying to establish a login mechanism using node.js, express and passport.js. The Login itself works quite nice, also sessions are stored nicely with redis but I do have some troubles with redirecting the user to where he started from before being prompted to authenticate.

e.g. User follows link http://localhost:3000/hidden is then redirected to http://localhost:3000/login but then I want him to be redirected again back to http://localhost:3000/hidden.

The purpose of this is, if the user access randomly a page he needs to be logged in first, he shall be redirected to the /login site providing his credentials and then being redirected back to the site he previously tried to access.

Here is my login post

app.post('/login', function (req, res, next) {
    passport.authenticate('local', function (err, user, info) {
        if (err) {
            return next(err)
        } else if (!user) { 
            console.log('message: ' + info.message);
            return res.redirect('/login') 
        } else {
            req.logIn(user, function (err) {
                if (err) {
                    return next(err);
                }
                return next(); // <-? Is this line right?
            });
        }
    })(req, res, next);
});

and here my ensureAuthenticated Method

function ensureAuthenticated (req, res, next) {
  if (req.isAuthenticated()) { 
      return next();
  }
  res.redirect('/login');
}

which hooks into the /hidden page

app.get('/hidden', ensureAuthenticated, function(req, res){
    res.render('hidden', { title: 'hidden page' });
});

The html output for the login site is quite simple

<form method="post" action="/login">

  <div id="username">
    <label>Username:</label>
    <input type="text" value="bob" name="username">
  </div>

  <div id="password">
    <label>Password:</label>
    <input type="password" value="secret" name="password">
  </div>

  <div id="info"></div>
    <div id="submit">
    <input type="submit" value="submit">
  </div>

</form>

Answer 1

In your ensureAuthenticated method save the return url in the session like this:

...
req.session.returnTo = req.originalUrl; 
res.redirect('/login');
...

Then you can update your passport.authenticate route to something like:

app.get('/auth/google/return', passport.authenticate('google'), function(req, res) {
    res.redirect(req.session.returnTo || '/');
    delete req.session.returnTo;
});