From: Kennedy Clark <hkclark@gmail.com>
Date: Wed, 27 May 2009 02:41:17 +0000 (+0000)
Subject: Contribution by Sebastian Willert about Cat 5.8 and Moose (thanks Sebastian!)
X-Git-Tag: v5.8005~134
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=catagits%2FCatalyst-Manual.git;a=commitdiff_plain;h=8a1018906a287d8f9e2896210f0556b58ae5452d

Contribution by Sebastian Willert about Cat 5.8 and Moose (thanks Sebastian!)
---

diff --git a/lib/Catalyst/Manual/CatalystAndMoose.pod b/lib/Catalyst/Manual/CatalystAndMoose.pod
new file mode 100644
index 0000000..fe5ba5b
--- /dev/null
+++ b/lib/Catalyst/Manual/CatalystAndMoose.pod
@@ -0,0 +1,123 @@
+=head1 NAME
+
+Catalyst::Manual::CatalystAndMoose - How Catalyst 5.8+ and Moose relate
+
+
+=head1 DESCRIPTION
+
+Since version 5.8 the core of Catalyst is based on L<Moose>. Although 
+the developers went through great lengths to allow for a seamless 
+transition, there are still a few things to keep in mind when trying 
+to exploit the power of L<Moose> in your Catalyst application.
+
+This document provides you with a short overview of common caveats and 
+best practices to use L<Moose>-based classes within Catalyst.
+
+
+=head1 THE CONTEXT CLASS
+
+A Moose-ified version of the context class should look like this:
+
+    package MyApp;
+    
+    use Moose;
+    use Catalyst;
+    
+    $app->config( name => 'MyApp' );
+    $app->setup(
+        # your roles and plugins
+    );
+    
+    # method modifiers must be created after setup because otherwise they will
+    # conflict with plugin overrides
+    
+    after 'finalize' => sub{
+        my $c = shift;
+        $c->log->info( 'done!' );
+    }
+
+You should also be aware, that roles in C<< $c->setup >> are applied 
+after the last plugin with all the benefits of using a single C<< 
+with() >> statement in an ordinary L<Moose> class and that your class 
+is automatically made immutable for you after the call to setup 
+(method modifiers in your class will work, though).
+
+CAVEAT: using roles in C<< $c->setup >> was implemented in Catalyst 
+version 5.80004. In prior versions you might get away with
+
+    after 'setup_plugins' => sub{ with(
+        # your roles
+    )};
+    
+    $app->setup(
+        # your plugins
+    );
+
+but this is discouraged and you should upgrade to 5.80004 anyway, 
+because it fixes a few important regression against 5.71
+
+[Q: COULD THIS BE USED TO RESOLVE CONFLICTS IN ROLES?].
+
+
+=head2 ACCESSORS
+
+Most of the request specific attributes like C<$c-&gt;stash>, 
+C<$c-&gt;request> and C<$c-&gt;response> have been converted to 
+L<Moose> attributes but without type constraints, attribute helpers or 
+builder methods. This ensures that Catalyst 5.8 is fully backwards 
+compatible to applications using the published API of Catalyst 5.7 but 
+slightly limits the gains that could be had by wielding the full power 
+of L<Moose> attributes.
+
+Most of the accessors to information gathered during compile time is 
+managed by C<Catalyst::ClassData>, which is a L<Moose>-aware version 
+of L<Class::Data::Inheritable> but not compatible with 
+L<MooseX::ClassAttribute>.
+
+
+=head2 ROLES AND METHOD MODIFIERS
+
+Since the release of Catalyst version 5.8 the only reason for creating 
+a Catalyst extension as a plugin is to provide backward compatibility 
+to applications still using version 5.7 but even then you should 
+consider building your plugin using L<Moose> and take advantage of 
+L<Moose::Manual::MethodModifiers|method modifiers> instead of 
+overriding methods to alter Catalyst's request lifecycle behavior.
+
+If backward compatibility is of no concern to you, you could as easily 
+rewrite your plugins as roles and enjoy all the benefits of automatic 
+method re-dispatching of C<< before >> and C<< after >> method 
+modifiers, naming conflict detecting and generally cleaner code.
+
+Plugins and roles should never use
+
+    after 'setup' => sub { ... } # wrong
+
+but rely on
+
+    after 'setup_finalize' => sub { ... } # this will work
+
+to run their own setup code if needed. If they need to influence the 
+setup process itself, they can modify C<< setup_dispatcher() >>, 
+C<< setup_engine()>>, C<< setup_stats() >>, C<< setup_components() >> 
+and C<< setup_actions() >>, but this should be done with due 
+consideration and as late as possible.
+
+
+=head1 CONTROLLERS
+
+To activate Catalyst's action attributes, Moose-ified controller 
+classes need to extend L<Catalyst::Controller> at compile time before 
+the actions themselves are declared:
+
+      package Catalyst::Controller::Root;
+    
+      use Moose;
+      BEGIN{
+            extends 'Catalyst::Controller';
+            with(
+                # your controller roles
+            );
+      }
+
+[MORE TO BE DONE!]