NAME

Catalyst::ActionSignatures - so you can stop looking at @_

SYNOPSIS

package MyApp::Controller::Example;

use Moose;
use MooseX::MethodAttributes;
use Catalyst::ActionSignatures;

extends 'Catalyst::Controller';

sub test($Req, $Res, Model::A $A, Model::Z $Z) :Local {
    # has $self implicitly
    $Res->body('Look ma, no @_!')
}

sub regular_method ($arg1, $arg1) {
  # has $self implicitly
}

__PACKAGE__->meta->make_immutable;

DESCRIPTION

Lets you declare required action dependencies via the method signature.

This subclasses signatures to allow you a more concise approach to creating your controllers. This injects your method signature into the code so you don't need to use @_. You should read signatures to be aware of any limitations.

For actions and regular controller methods, "$self" is implicitly injected, but '$c' is not. You should add that to the method signature if you need it although you are encouraged to name your dependencies rather than hang it all after $c.

You should review Catalyst::ActionRole::MethodSignatureDependencyInjection for more on how to construct signatures.

Also Catalyst::ActionSignatures::Rationale may be useful.

Args and Captures

If you specify args and captures in your method signature, you can leave off the associated method attributes (Args($n) and CaptureArgs($n)) IF the method signature is the full specification. In other works instead of:

 sub chain(Model::A $a, Capture $id, $res) :Chained(/) CaptureArgs(1) {
   Test::Most::is $id, 100;
   Test::Most::ok $res->isa('Catalyst::Response');
 }

   sub endchain($res, Arg0 $name) :Chained(chain) Args(1) {
     $res->body($name);
   }

   sub endchain2($res, Arg $first, Arg $last) :Chained(chain) PathPart(endchain) Args(2) {
     $res->body("$first $last");
   }

You can do:

 sub chain(Model::A $a, Capture $id, $res) :Chained(/) {
   Test::Most::is $id, 100;
   Test::Most::ok $res->isa('Catalyst::Response');
 }

   sub endchain($res, Arg0 $name) :Chained(chain)  {
     $res->body($name);
   }

   sub endchain2($res, Arg $first, Arg $last) :Chained(chain) PathPart(endchain)  {
     $res->body("$first $last");
   }

Type Constraints

If you are using a newer Catalyst (greater that 5.90090) you may declare your Args and CaptureArgs typeconstraints via the method signature.

use Types::Standard qw/Int Str/;

sub chain(Model::A $a, Capture $id isa Int, $res) :Chained(/) {
  Test::Most::is $id, 100;
  Test::Most::ok $res->isa('Catalyst::Response');
}

  sub typed0($res, Arg $id) :Chained(chain) PathPart(typed) {
    $res->body('any');
  }

  sub typed1($res, Arg $pid isa Int) :Chained(chain) PathPart(typed) {
    $res->body('int');
  }

NOTE If you declare any type constraints on args or captures, all declared args or captures must have them.

Implicit 'CaptureArgs(0)' and 'Args(0)' in chained actions

If you fail to use an Args or CaptureArgs attributes and you do not declare any captures or args in your chained action method signatures, we automatically add a CaptureArgs(0) attribute. However, since we cannot properly detect the end of a chain, you must still use Args(0) to terminate chains when the last action has no arguments. You may instead use "Chained(link/)" and note the terminal '/' in the chained attribute value to declare a terminal Chain with an implicit Args(0).

sub another_chain() :Chained(/) { }

  sub another_end($res) :Chained(another_chain/) {
    $res->body('another_end');
  }

Model and View parameters

If your Model or View is a factory that takes parameters, you may supply those from other existing dependencies:

# like $c->model('ReturnsArg', $id);
sub from_arg($res, Model::ReturnsArg<Arg $id isa '"Int"'> $model) :Local {
  $res->body("model $model");
  # $id is also available.
}

ENVIRONMENT VARIABLES.

Set CATALYST_METHODSIGNATURES_DEBUG to true to get initial debugging output of the generated method signatures and attribute changes. Useful if you are having trouble and want some help to offer a patch!

SEE ALSO

Catalyst::Action, Catalyst, signatures, Catalyst::ActionRole::MethodSignatureDependencyInjection

AUTHOR

John Napiorkowski email:[email protected]

COPYRIGHT & LICENSE

Copyright 2015, John Napiorkowski email:[email protected]

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