1 package Catalyst::Component;
4 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
11 Catalyst::Component - Catalyst Component Base Class
15 # lib/MyApp/Model/Something.pm
16 package MyApp::Model::Something;
18 use base 'Catalyst::Component';
20 __PACKAGE__->config( foo => 'bar' );
28 my ( $self, $c ) = @_;
29 $c->response->output( $self->{foo} );
34 # Methods can be a request step
35 $c->forward(qw/MyApp::Model::Something forward_to_me/);
38 print $c->comp('MyApp::Model::Something')->test;
40 print $c->comp('MyApp::Model::Something')->{foo};
44 This is the universal base class for Catalyst components
45 (Model/View/Controller).
47 It provides you with a generic new() for instantiation through Catalyst's
48 component loader with config() support and a process() method placeholder.
52 __PACKAGE__->mk_classdata($_) for qw/_config _plugins/;
57 my ( $self, $c ) = @_;
59 # Temporary fix, some components does not pass context to constructor
60 my $arguments = ( ref( $_[-1] ) eq 'HASH' ) ? $_[-1] : {};
62 return $self->NEXT::new(
63 $self->merge_config_hashes( $self->config, $arguments ) );
67 my ( $self, $c ) = @_;
69 # Temporary fix, some components does not pass context to constructor
70 my $arguments = ( ref( $_[-1] ) eq 'HASH' ) ? $_[-1] : {};
72 if ( my $new = $self->NEXT::COMPONENT( $c, $arguments ) ) {
76 if ( my $new = $self->new( $c, $arguments ) ) {
80 my $class = ref $self || $self;
81 my $new = $self->merge_config_hashes(
82 $self->config, $arguments );
83 return bless $new, $class;
90 my $config_sub = $self->can('_config');
91 my $config = $self->$config_sub() || {};
93 my $newconfig = { %{@_ > 1 ? {@_} : $_[0]} };
95 $self->merge_config_hashes( $config, $newconfig )
98 # this is a bit of a kludge, required to make
99 # __PACKAGE__->config->{foo} = 'bar';
100 # work in a subclass. Calling the Class::Data::Inheritable setter
101 # will create a new _config method in the current class if it's
102 # currently inherited from the superclass. So, the can() call will
103 # return a different subref in that case and that means we know to
104 # copy and reset the value stored in the class data.
106 $self->_config( $config );
108 if ((my $config_sub_now = $self->can('_config')) ne $config_sub) {
110 $config = $self->merge_config_hashes( $config, {} );
111 $self->$config_sub_now( $config );
117 sub merge_config_hashes {
118 my ( $self, $lefthash, $righthash ) = @_;
120 return Catalyst::Utils::merge_hashes( $lefthash, $righthash );
125 Catalyst::Exception->throw( message => ( ref $_[0] || $_[0] )
126 . " did not override Catalyst::Component::process" );
135 =head2 new($c, $arguments)
137 Called by COMPONENT to instantiate the component; should return an object
138 to be stored in the application's component hash.
140 =head2 COMPONENT($c, $arguments)
142 If this method is present (as it is on all Catalyst::Component subclasses,
143 it is called by Catalyst during setup_components with the application class
144 as $c and any config entry on the application for this component (for example,
145 in the case of MyApp::Controller::Foo this would be
146 MyApp->config->{'Controller::Foo'}). The arguments are expected to be a
147 hashref and are merged with the __PACKAGE__->config hashref before calling
148 ->new to instantiate the component.
152 =head2 $c->config($hashref)
154 =head2 $c->config($key, $value, ...)
156 Accessor for this component's config hash. Config values can be set as
157 key value pair, or you can specify a hashref. In either case the keys
158 will be merged with any existing config settings. Each component in
159 a Catalyst application has it's own config hash.
163 This is the default method called on a Catalyst component in the dispatcher.
164 For instance, Views implement this action to render the response body
165 when you forward to them. The default is an abstract method.
167 =head2 $c->merge_config_hashes( $hashref, $hashref )
169 Merges two hashes together recursively, giving right-hand precedence.
170 Alias for the method in L<Catalyst::Utils>.
172 =head1 OPTIONAL METHODS
174 =head2 ACCEPT_CONTEXT($c, @args)
176 Catalyst components are normally initalized during server startup, either
177 as a Class or a Instance. However, some components require information about
178 the current request. To do so, they can implement an ACCEPT_CONTEXT method.
180 If this method is present, it is called during $c->comp/controller/model/view
181 with the current $c and any additional args (e.g. $c->model('Foo', qw/bar baz/)
182 would cause your MyApp::Model::Foo instance's ACCEPT_CONTEXT to be called with
183 ($c, 'bar', 'baz')) and the return value of this method is returned to the
184 calling code in the application rather than the component itself.
188 L<Catalyst>, L<Catalyst::Model>, L<Catalyst::View>, L<Catalyst::Controller>.
192 Sebastian Riedel, C<sri@cpan.org>
193 Marcus Ramberg, C<mramberg@cpan.org>
194 Matt S Trout, C<mst@shadowcatsystems.co.uk>
198 This program is free software, you can redistribute it and/or modify it under
199 the same terms as Perl itself.