Fixes rt.cpan.org #57361

[catagits/Catalyst-Manual.git] / lib / Catalyst / Manual / Actions.pod

=head1 NAME

Catalyst::Manual::Actions - Catalyst Reusable Actions 

=head1 DESCRIPTION

This section of the manual describes the reusable action system in
Catalyst, how such actions work, descriptions of some existing ones, and
how to write your own.  Reusable actions are attributes on Catalyst
methods that allow you to decorate your method with functions running
before or after the method call.  This can be used to implement commonly
used action patterns, while still leaving you full freedom to customize
them.

=head1 USING ACTIONS

This is pretty simple. Actions work just like the normal dispatch
attributes you are used to, like Local or Private:

  sub Hello :Local :ActionClass('SayBefore') { 
	$c->res->output( 'Hello '.$c->stash->{what} );
  }

In this example, we expect the SayBefore action to magically populate
stash with something relevant before C<Hello> is run.  In the next
section we'll show you how to implement it. If you want it in a
namespace other than Catalyst::Action you can prefix the action name
with a '+', for instance '+Foo::SayBefore', or if you just want it under
your application namespace instead, use MyAction, like
MyAction('SayBefore').

=head1 WRITING YOUR OWN ACTIONS

Implementing the action itself is almost as easy. Just use
L<Catalyst::Action> as a base class and decorate the C<execute> call in
the Action class:

  package Catalyst::Action::MyAction;
  use Moose;
  use namespace::autoclean;
  
  extends 'Catalyst::Action';

  before 'execute' => sub {
    my ( $self, $controller, $c, $test ) = @_;
    $c->stash->{what} = 'world';
  };

  after 'execute' => sub {
      my ( $self, $controller, $c, $test ) = @_;
      $c->stash->{foo} = 'bar';
  };

  __PACKAGE__->meta->make_immutable;

Pretty simple, huh?

=head1 ACTION ROLES

You can only have one action class per action, which can be somewhat
inflexible.

The solution to this is to use L<Catalyst::Controller::ActionRole>, which
would make the example above look like this:

  package Catalyst::ActionRole::MyActionRole;
  use Moose::Role;

  before 'execute' => sub {
    my ( $self, $controller, $c, $test ) = @_;
    $c->stash->{what} = 'world';
  };

  after 'execute' => sub {
      my ( $self, $controller, $c, $test ) = @_;
      $c->stash->{foo} = 'bar';
  };
  
  1;

and this would be used in a controller like this:

  package MyApp::Controller::Foo;
  use Moose;
  use namespace::autoclean;
  BEGIN { extends 'Catalyst::Controller::ActionRole'; }

  sub foo : Does('MyActionRole') {
      my ($self, $c) = @_;
  }

  1;

=head1 EXAMPLE ACTIONS

=head2 Catalyst::Action::RenderView

This is meant to decorate end actions. It's similar in operation to 
L<Catalyst::Plugin::DefaultEnd>, but allows you to decide on an action
level rather than on an application level where it should be run.

=head2 Catalyst::Action::REST

Provides additional syntax for dispatching based upon the HTTP method
of the request.

=head1 EXAMPLE ACTIONROLES

=head2 Catalyst::ActionRole::ACL

Provides ACLs for role membership by decorating your actions.

=head1 AUTHORS

Catalyst Contributors, see Catalyst.pm

=head1 COPYRIGHT

This library is free software. You can redistribute it and/or modify it under
the same terms as Perl itself.

=cut