1Catalyst::Manual::CatalUyssetrAnCdoMnotorsieb(u3t)ed PerClatDaolcyusmte:n:tMaatniuoanl::CatalystAndMoose(3)
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NAME

6       Catalyst::Manual::CatalystAndMoose - How Catalyst 5.8+ and Moose relate
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DESCRIPTION

9       Since version 5.8, the core of Catalyst is based on Moose. Although the
10       developers went through great lengths to allow for a seamless
11       transition, there are still a few things to keep in mind when trying to
12       exploit the power of Moose in your Catalyst application.
13
14       This document provides you with a short overview of common caveats and
15       best practices for using Moose-based classes within Catalyst.
16

THE CONTEXT CLASS

18       A Moose-ified version of the context class should look like this:
19
20           package MyApp;
21           use Moose;
22           use namespace::autoclean;
23           use Catalyst (
24               # your roles and plugins
25           );
26           extends 'Catalyst';
27
28           # If you want to use method modifiers to adjust the setup process, (e.g. setup_finalize)
29           # they must be here, before the call to setup (advanced users only)
30
31           $app->config( name => 'MyApp' );
32           $app->setup;
33
34           # method modifiers generally must be created after setup because otherwise they will
35           # conflict with plugin overrides
36
37           after 'finalize' => sub {
38               my $c = shift;
39               $c->log->info( 'done!' );
40           }
41
42       You should also be aware that roles in "$c->setup" are applied after
43       the last plugin with all the benefits of using a single with()
44       statement in an ordinary Moose class.
45
46       Your class is automatically made immutable at the end of the current
47       file.
48
49       CAVEAT: Using roles in "$c->setup" was implemented in Catalyst version
50       5.80004. In prior versions you might get away with
51
52           after 'setup_plugins' => sub{ with(
53               # your roles
54           )};
55
56           $app->setup(
57               # your plugins
58           );
59
60       but this is discouraged and you should upgrade to 5.80004 anyway,
61       because it fixes a few important regressions against 5.71
62
63       CAVEAT: Using roles in "$c->setup" will not currently allow you to pass
64       parameters to roles, or perform conflict resolution.  Conflict
65       detection still works as expected.
66
67   ACCESSORS
68       Most of the request-specific attributes like "$c->stash", "$c->request"
69       and "$c->response" have been converted to Moose attributes but without
70       type constraints, attribute helpers or builder methods. This ensures
71       that Catalyst 5.8 is fully backwards compatible to applications using
72       the published API of Catalyst 5.7 but slightly limits the gains that
73       could be had by wielding the full power of Moose attributes.
74
75       Most of the accessors to information gathered during compile time (such
76       as configuration) are managed by Catalyst::ClassData, which is a
77       Moose-aware version of Class::Data::Inheritable but not compatible with
78       MooseX::ClassAttribute.
79
80   ROLES AND METHOD MODIFIERS
81       Since the release of Catalyst version 5.8, the only reason for creating
82       a Catalyst extension as a plugin is to provide backward compatibility
83       to applications still using version 5.7.
84
85       If backward compatibility is of no concern to you, you could as easily
86       rewrite your plugins as roles and enjoy all the benefits of automatic
87       method re-dispatching of "before" and "after" method modifiers, naming
88       conflict detection and generally cleaner code.
89
90       NOTE
91
92       Plugins and roles should never use
93
94           after 'setup' => sub { ... } # wrong
95
96       (or any other method of hooking the setup method) but rely on
97
98           after 'setup_finalize' => sub { ... } # this will work
99
100       to run their own setup code if needed. If they need to influence the
101       setup process itself, they can modify "setup_dispatcher()",
102       "setup_engine()", "setup_stats()", "setup_components()" and
103       "setup_actions()", but this should be done with due consideration and
104       as late as possible.
105

CONTROLLERS

107       To activate Catalyst's action attributes, Moose-ified controller
108       classes need to extend Catalyst::Controller at compile time, before the
109       actions themselves are declared:
110
111             package Catalyst::Controller::Root;
112             use Moose;
113             use namespace::autoclean;
114
115             BEGIN { extends 'Catalyst::Controller'; }
116
117   Controller Roles
118       It is possible to use roles to apply method modifiers on controller
119       actions from 5.80003 onwards, or use modifiers in your controller
120       classes themselves. For example
121
122           package MyApp::Controller::Foo;
123           use Moose;
124           use namespace::autoclean;
125           BEGIN { extends 'Catalyst::Controller' };
126
127           sub foo : Local {
128               my ($self, $c) = @_;
129               $c->res->body('Hello ');
130           }
131           after foo => sub {
132               my ($self, $c) = @_;
133               $c->res->body($c->res->body . 'World');
134           };
135
136       It is possible to have action methods with attributes inside Moose
137       roles, using MooseX::MethodAttributes, example:
138
139           package MyApp::ControllerRole;
140           use MooseX::MethodAttributes::Role;
141           use namespace::autoclean;
142
143           sub foo : Local {
144               my ($self, $c) = @_;
145               ...
146           }
147
148           package MyApp::Controller::Foo;
149           use Moose;
150           use namespace::autoclean;
151           BEGIN { extends 'Catalyst::Controller' };
152
153           with 'MyApp::ControllerRole';
154

AUTHORS

156       Catalyst Contributors, see Catalyst.pm
157

159       This library is free software. You can redistribute it and/or modify it
160       under the same terms as Perl itself.
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164perl v5.32.0                      2020-07-C2a8talyst::Manual::CatalystAndMoose(3)
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