NAME

HTML::FormHandler::Manual::Catalyst - Using HFH forms in Catalyst controllers

SYNOPSIS

This part of the FormHandler Manual is devoted to using the HTML::FormHandler package in Catalyst controllers.

See the other FormHandler documentation at HTML::FormHandler::Manual, or the base class at HTML::FormHandler.

DESCRIPTION

Although HTML::FormHandler can be used in any Perl web application, module, or script, one of its most common uses is in Catalyst applications.

Using a form takes only a few lines of code, so it's not necessary to have a Catalyst base controller, although you could make a base controller for FormHandler if you're doing more than the basics.

A Controller Example

The following example uses chained dispatching. The 'form' method is called by both the create and edit actions.

   package BookDB::Controller::Borrower;

   use Moose;
   BEGIN { extends 'Catalyst::Controller' }

   sub borrower_base : Chained PathPart('borrower') CaptureArgs(0) { }

   sub list : Chained('borrower_base') PathPart('list') Args(0) {
      my ( $self, $c ) = @_;
      my $borrowers = [ $c->model('DB::Borrower')->all ];
      my @columns = ( 'name', 'email' );
      $c->stash( borrowers => $borrowers, columns => \@columns,
                 template => 'borrower/list.tt' );
   }

   sub add : Chained('borrower_base') PathPart('add') Args(0) {
      my ( $self, $c ) = @_;
      # Create the empty borrower row for the form
      $c->stash( borrower => $c->model('DB::Borrower')->new_result({}) );
      return $self->form($c);
   }

   sub item : Chained('borrower_base') PathPart('') CaptureArgs(1) {
      my ( $self, $c, $borrower_id ) = @_;
      $c->stash( borrower => $c->model('DB::Borrower')->find($borrower_id) );
   }

   sub edit : Chained('item') PathPart('edit') Args(0) {
      my ( $self, $c ) = @_;
      return $self->form($c);
   }

   sub form {
      my ( $self, $c ) = @_;

      my $form = BookDB::Form::Borrower->new;
      $c->stash( form => $form, template => 'borrower/form.tt' );
      return unless $form->process( item => $c->stash->{borrower},
         params => $c->req->parameters );
      $c->res->redirect( $c->uri_for($self->action_for('list')) );
   }

   sub delete : Chained('item') PathPart('delete') Args(0) {
      my ( $self, $c ) = @_;

      $c->stash->{borrower}->delete;
      $c->res->redirect( $c->uri_for($c->action_for('list')) );
   }

   1;

Another way to set up your form

If you are setting the schema or other form attributes (such as the user_id, or other attributes) on your form you could create a base controller that would set these in the form on each call using Catalyst::Component::InstancePerContext, or set them in a base Chained method.

   sub book_base : Chained PathPart('book') CaptureArgs(0) {
      my ( $self, $c ) = @_;
      my $form = MyApp::Form->new;  
      $form->schema( $c->model('DB')->schema );
      $form->params( $c->req->parameters );
      $form->user_id( $c->user->id );
      $c->stash( form => $form );
   }

Then you could just pass in the item_id when the form is processed.

   return unless $c->stash->{form}->process($id);

Using HTML::FillInForm

If you want to use HTML::FillInForm to fill in values instead of the doing it in directly in a template using either the field or the form 'fif' methods, you can use Catalyst::View::FillInForm on your view class:

    package MyApp::View::TT;
    use Moose;
    with 'Catalyst::View::FillInForm';
    ....
    1;

and set the 'fif' hash in the 'fillinform' stash variable:

    $self->form->process( ... );
    $c->stash( fillinform => $self->form->fif );
    return unless $form->validated;

When the 'fillinform' stash variable is set, HTML::FillInForm will automatically be used by your view to fill in the the form values. This can be very helpful when you want to build your forms by hand, or when you have legacy forms that you're just trying to hook up to FormHandler.

The Catalyst context

FormHandler has a 'ctx' attribute that can be used to set the Catalyst context (or anything you want, really). But if you can avoid passing in the context, you should do so, because you're mixing up your MVC and it makes it much more difficult to test your forms. But if you need to do it, you can:

    my $form = MyApp::Form->new( ctx => $c );

Usually you should prefer to add new attributes to your form:

    package MyApp::Form;
    use HTML::FormHandler::Moose;
    extends 'HTML::FormHandler';

    has 'user_id' => ( is => 'rw' );
    has 'hostname' => ( is => 'rw' );
    has 'captcha_store' => ( is => 'rw' );
    ....
    1;

Then just pass the attributes in on new:

    my $form => MyApp::Form->new( user_id => $c->user->id, hostname => $c->req->host,
        captcha_store => $c->{session}->{captcha} );
   

Or set them using accessors:

    $form->user_id( $c->user->id );
    $form->hostname( $c->req->host );
    $form->captcha_store( $c->{session}->{captcha} );

Then you can access these attributes in your form validation methods:

    sub validate_selection {
       my ( $self, $field ) = @_;
       if( $field->value eq 'something' && $self->hostname eq 'something_else' )
       {
          $field->add_error("some error message" );
       }
    }

cpanm HTML::FormHandler

perl -MCPAN -e shell
install HTML::FormHandler