ForkTemplate

Here's a little chunk of code you can use in a template to send different responses depending upon a condition of your choice, without hardcoding your variants into the code:

{my $dummy="Reminder to include a blank line above your actual text if not including any headers";}
    
    Optional common intro
    
    {
      use RT::Template;
      use Encode;
      my $selector = $Ticket->FirstCustomFieldValue('selector');
      my $obj = new RT::Template($RT::SystemUser);
      $obj->Load( $selector < 5 ? 'Template A' : 'Template B');
    
      if ($obj->Type == 'Perl') {
         my($ret, $msg) = $obj->Parse();
         $ret ? Encode::decode( 'utf-8', $obj->MIMEObj->stringify_body) : $msg;
      } else {
         $obj->Content();
      }
    }
    
    Optional common outro
    
    

This will inject the contents of another template into the current one. It's an easy way to provide some common and some specific content in a response, or to create a template which acts as a switch without having to create separate scrips for each condition. The latter effect could also be achieved through the clever use of $self->SetTemplate in CustomCondition.

my $trans = $self->TransactionObj;
return 0 unless $trans->Type eq "Create";
$self->SetTemplate( $condition ? 'foo' : 'bar' );