When a user submits a form, your response may entail several different actions:

validation

was the submitted form data intelligible?

authentication

was the submitted form data/cookie something that allows you to figure out who this person is?

authorization

was the person who submitted form data/cookie somethone that has a right to request this page?

execution

Perform the actions requested by hitting the submit button. E.g. update user info.

So now that you understand these steps, let's see why I am bothering posting all this. Let's assume you have presented a user with an information update screen. The user enters some (possibly invalid) data and hits submit. The following then occurs in CGI::Prototype::activate

1. the dispatch routine is called. This routine will determine that a user has submitted user update information. Now it is up to a package, say, MyApp::Update::Validate to determine the response. Here is pseudocode for that:

   package MyApp::Update::Validate; 
    
   sub response { 
    
     my $response; 
    
     if (not validated) { 
       $response = 'Redo'; 
     } elsif (not authenticated) { 
       $response = 'NotAuthenticated' 
     } elsif (not authorized) { 
       $response = 'NotAuthorized'; 
     } else { 
       $response = 'HandleUpdate'  # model action: update user info 
     } 
    
     $response = "MyApp::Login::$response"; 
    
     return $response; 
    
   }
   [download]

But the question becomes where do model actions occur and how do we change pages based on this?