in reply to CGI::Application design strategy

I'm used to write two runmodes for every panel in my application. In your case, they would be login and login_update. Given a method redirect to set the appropriate headers, the code could be the following (not-so-pseudo-code): 
# Does nothing except printing the form.
# Using sessions you can pass to it an error_message,
# for example.
#
sub login                                                             
+          
{   
    my $self = shift;                                                 
+          
    
    my $tmpl = $self->load_tmpl( 'login' );                           
+          
    
    return $tmpl->output();                                           
+          
}   

sub login_update                                                      
+          
{   
    my $self = shift;                                                 
+          
    my $q    = $self->query;
  
    # Fetch username and password from the form
    #  
    
    if ( PASSWORD CORRECT ) {        
        
        $self->redirect( { rm => 'first_panel' } );           
    }
    else {

        # It could store some useful info in a session,
        # for example the error message.
        #
        $self->redirect( { rm => 'login' } );
    }

    return;
}

[download]
I use this technique a lot, and it has proven its flexibility and efficiency.

Replies are listed 'Best First'.
Re: Re: CGI::Application design strategy
by simon.proctor (Vicar) on Mar 02, 2004 at 15:47 UTC
    I realise you say the above is psuedo code but I have to ask. How do you normally represent: 
    $self->redirect( { rm => 'first_panel' } );

    [download]
    In your normal applications? Do you have a template method like the following (this is naturally untested): 
    sub redirect {
    my $self = shift;
    my $mode = shift;
    my $new_url = $self->param('app_url') . $mode->{'rm'};
    $self->header_type('redirect');
    $self->header_props(-url=>$new_url);
    return "Redirecting to $new_url";
  }

    [download]
    I ask as I have wanted to switch between run modes based on data and have had to stick with these kind of methods. Either that or I call the runmode method directly.

    Just a quick question - I'm sure the answer is yes but I thought I would ask anyhoo.
[reply]
[d/l]
[select]
      The answer is yes. My actual code is pretty similar to yours. 
      sub build_redirect
{       
  my ($self, $form, $script) = @_;
    
  $form ||= {};                                                       
+          
  my $q = $self->query;
  my $uri = URI->new( $script || $q->script_name );                   
+          
  $uri->query_form(%$form);                                           
+          
        
  return $uri->as_string;
}       
        
sub redirect
{       
  my $self = shift;                                                   
+          
    
  $self->header_add( -uri => $self->build_redirect( @_ ) );           
+          
  $self->header_type('redirect');                                     
+          
}

      [download]
[reply]
[d/l]

      If you want to switch run modes in mid-stream your current run mode just has to call the runmode that you want.

      There is never any need for a normal CGI::Application based app to use redirect headers to access another runmode unless the resource has actually moved (e.g. has a new URL)

      Here is larsen's example modified updated to remove the redirect. 

      


# Does nothing except printing the form.
# Using sessions you can pass to it an error_message,
# for example.
#
sub login                                                             
+          
{   
    my $self = shift;                                                 
+          
    
    my $tmpl = $self->load_tmpl( 'login' );                           
+          
    
    return $tmpl->output();                                           
+          
}   

sub login_update                                                      
+          
{   
    my $self = shift;                                                 
+          
    my $q    = $self->query;
  
    # Fetch username and password from the form
    #  
    
    if ( PASSWORD CORRECT ) {        
        
        return $self->first_panel;           
    }
    else {

        # It could store some useful info in a session,
        # for example the error message.
        #
        return $self->login;
    }

    # You have a problem if this return ever actually executed
    #return;
}

      [download]
      --
      Clayton
[reply]
[d/l]

        And can you tell me what happens when users hit reload on their browsers? If you redirect users, they will not be able to reissue a command by reloading the login_update run mode. Nice, isn't it? :)

        Ciao, Valerio

[reply]

In Section Seekers of Perl Wisdom