Mojolicious flash messages

Question

I am building an authentication system based upon the one found here:

https://github.com/alexanderBendo/Experiments/blob/master/exp0001/mojolicious-auth-session.pl

The problem I am having is that if a user enters the wrong username or password, the server is returning the flash message as if they tried to access a page without being logged in. It should be displaying an Invalid Credentials message. If I enter the bad credentials a second time, I get the Invalid Credentials message.

Here is the pertinent code:

sub main {
  my $self = shift;
 if ( $self->is_user_authenticated ) {
    $self->redirect_to('/main/cp');
  } else {
    $self->flash( message => 'You must log in to view this page' );
    $self->render('login');
  }
}

sub login {
  my $self = shift;
    my $user = $self->param('name') || q{};
    my $pass = $self->param('pass') || q{};
    if ( $self->authenticate( $user, $pass ) ) {
      $self->redirect_to('/main/cp');
    } else {
      $self->flash( message => 'Invalid credentials!' );
      $self->render('login');
      return;
    }
}

Template:

% layout 'default';
% title 'Login';
<h1>Log In</h1>
<% if (my $message = flash 'message' ) { %>
<b><%= $message %></b><br>
<% } %>
<%= form_for login => (method => 'post') => begin %>
Name: <%= text_field 'name' %>
<br>
Password: <%= password_field 'pass' %>
<br>
<%= submit_button 'Login' %>
<% end %>

Thanks.

Answer 1

Flash need to use to save data between current and next query in session. So, flash data is placed not immediately in session.

So, you must to do redirect_to('login_page') except render('login_page').

If you don't want to do redirect you must to save your data into stash:

sub main {
  my $self = shift;
 if ( $self->is_user_authenticated ) {
    $self->redirect_to('/main/cp');
  } else {
    $self->stash( message => 'You must log in to view this page' );
    $self->render('login');
  }
}

Template:

% layout 'default';
% title 'Login';
<h1>Log In</h1>
<% if (my $message = stash 'message' ) { %>
<b><%= $message %></b><br>
<% } %>