1 package Catalyst::Component;
5 use Class::MOP::Object;
7 use Class::C3::Adopt::NEXT;
11 with 'MooseX::Emulate::Class::Accessor::Fast';
12 with 'Catalyst::ClassData';
17 Catalyst::Component - Catalyst Component Base Class
21 # lib/MyApp/Model/Something.pm
22 package MyApp::Model::Something;
24 use base 'Catalyst::Component';
26 __PACKAGE__->config( foo => 'bar' );
34 my ( $self, $c ) = @_;
35 $c->response->output( $self->{foo} );
40 # Methods can be a request step
41 $c->forward(qw/MyApp::Model::Something forward_to_me/);
44 print $c->comp('MyApp::Model::Something')->test;
46 print $c->comp('MyApp::Model::Something')->{foo};
50 This is the universal base class for Catalyst components
51 (Model/View/Controller).
53 It provides you with a generic new() for instantiation through Catalyst's
54 component loader with config() support and a process() method placeholder.
58 __PACKAGE__->mk_classdata('_plugins');
59 __PACKAGE__->mk_classdata('_config');
64 # Temporary fix, some components does not pass context to constructor
65 my $arguments = ( ref( $_[-1] ) eq 'HASH' ) ? $_[-1] : {};
67 my $args = $self->merge_config_hashes( $self->config, $arguments );
73 my ( $self, $c ) = @_;
75 # Temporary fix, some components does not pass context to constructor
76 my $arguments = ( ref( $_[-1] ) eq 'HASH' ) ? $_[-1] : {};
77 if( my $next = $self->next::can ){
78 my $class = blessed $self || $self;
79 my ($next_package) = Class::MOP::get_code_info($next);
80 warn "There is a COMPONENT method resolving after Catalyst::Component in ${next_package}.\n";
81 warn "This behavior can no longer be supported, and so your application is probably broken.\n";
82 warn "Your linearised isa hierarchy is: " . join(', ', mro::get_linear_isa($class)) . "\n";
83 warn "Please see perldoc Catalyst::Upgrading for more information about this issue.\n";
85 return $self->new($c, $arguments);
90 my $config = $self->_config || {};
92 my $newconfig = { %{@_ > 1 ? {@_} : $_[0]} };
94 $self->merge_config_hashes( $config, $newconfig )
97 # this is a bit of a kludge, required to make
98 # __PACKAGE__->config->{foo} = 'bar';
100 my $class = blessed($self) || $self;
101 my $meta = Class::MOP::get_metaclass_by_name($class);
102 unless ($meta->has_package_symbol('$_config')) {
104 $config = $self->merge_config_hashes( $config, {} );
105 $self->_config( $config );
111 sub merge_config_hashes {
112 my ( $self, $lefthash, $righthash ) = @_;
114 return Catalyst::Utils::merge_hashes( $lefthash, $righthash );
119 Catalyst::Exception->throw( message => ( ref $_[0] || $_[0] )
120 . " did not override Catalyst::Component::process" );
125 __PACKAGE__->meta->make_immutable;
132 =head2 new($c, $arguments)
134 Called by COMPONENT to instantiate the component; should return an object
135 to be stored in the application's component hash.
137 =head2 COMPONENT($c, $arguments)
139 If this method is present (as it is on all Catalyst::Component subclasses,
140 it is called by Catalyst during setup_components with the application class
141 as $c and any config entry on the application for this component (for example,
142 in the case of MyApp::Controller::Foo this would be
143 MyApp->config->{'Controller::Foo'}). The arguments are expected to be a
144 hashref and are merged with the __PACKAGE__->config hashref before calling
145 ->new to instantiate the component.
149 =head2 $c->config($hashref)
151 =head2 $c->config($key, $value, ...)
153 Accessor for this component's config hash. Config values can be set as
154 key value pair, or you can specify a hashref. In either case the keys
155 will be merged with any existing config settings. Each component in
156 a Catalyst application has it's own config hash.
160 This is the default method called on a Catalyst component in the dispatcher.
161 For instance, Views implement this action to render the response body
162 when you forward to them. The default is an abstract method.
164 =head2 $c->merge_config_hashes( $hashref, $hashref )
166 Merges two hashes together recursively, giving right-hand precedence.
167 Alias for the method in L<Catalyst::Utils>.
169 =head1 OPTIONAL METHODS
171 =head2 ACCEPT_CONTEXT($c, @args)
173 Catalyst components are normally initialized during server startup, either
174 as a Class or a Instance. However, some components require information about
175 the current request. To do so, they can implement an ACCEPT_CONTEXT method.
177 If this method is present, it is called during $c->comp/controller/model/view
178 with the current $c and any additional args (e.g. $c->model('Foo', qw/bar baz/)
179 would cause your MyApp::Model::Foo instance's ACCEPT_CONTEXT to be called with
180 ($c, 'bar', 'baz')) and the return value of this method is returned to the
181 calling code in the application rather than the component itself.
185 L<Catalyst>, L<Catalyst::Model>, L<Catalyst::View>, L<Catalyst::Controller>.
189 Catalyst Contributors, see Catalyst.pm
193 This program is free software, you can redistribute it and/or modify it under
194 the same terms as Perl itself.