c.came_from = url('home')

        if request.POST:

            # import Login Form validator class

            login_form = LoginForm()()

            try:

                c.form_result = login_form.to_python(dict(request.POST))

                username = c.form_result['username']

                user = User.get_by_username_or_email(username)

                assert user is not None  # the same user get just passed in the form validation

            except formencode.Invalid as errors:

                defaults = errors.value

                # remove password from filling in form again

                # container auth or other auth functions that create users on

                # the fly can throw this exception signaling that there's issue

                # with user creation, explanation should be provided in

                # Exception itself

                h.flash(e, 'error')

            else:

                auth_user = log_in_user(user, c.form_result['remember'], is_external_auth=False, ip_addr=request.ip_addr)

                if auth_user:

                    raise HTTPFound(location=c.came_from)

                h.flash(_('Authentication failed.'), 'error')

        else:

            # redirect if already logged in