returnTo behavior error. Url gets removed right before the post request

Question

I am using express session and I have a middleware that sets the req.session.returnTo to the orginalUrl.

router.post(
  '/login',
  passport.authenticate('local', {
    failureFlash: true,
    failureRedirect: '/login',
  }),
  (req, res) => {
    const redirectUrl = req.session.returnTo || '/home';
    delete req.session.returnTo;
    res.redirect(redirectUrl);
  }
);

This is my code that redirects to the originalUrl if there is. I logged the whole session and the url is there under returnTo but gets removed right before this post request.

I tried removing the delete req.session.returnTo and it still doesnt work. It is there when the app makes a get request to /login but gets removed right before /post and then it always redirects to /home.

Answer 1

Add keepSessionInfo: true to passport.authenticate.

 router.post(
  '/login',
  passport.authenticate('local', {
    failureFlash: true,
    failureRedirect: '/login',
    keepSessionInfo: true
  }),
  (req, res) => {
    const redirectUrl = req.session.returnTo || '/home';
    delete req.session.returnTo;
    res.redirect(redirectUrl);
  }
);