package Catalyst::Component;
use Moose;
use Class::MOP;
use Class::MOP::Object;
use Catalyst::Utils;
use Class::C3::Adopt::NEXT;
use Devel::InnerPackage ();
use MRO::Compat;
use mro 'c3';
use Scalar::Util 'blessed';
use Class::Load 'is_class_loaded';
use Moose::Util 'find_meta';
use namespace::clean -except => 'meta';
with 'MooseX::Emulate::Class::Accessor::Fast';
with 'Catalyst::ClassData';
=head1 NAME
Catalyst::Component - Catalyst Component Base Class
=head1 SYNOPSIS
# lib/MyApp/Model/Something.pm
package MyApp::Model::Something;
use base 'Catalyst::Component';
__PACKAGE__->config( foo => 'bar' );
has foo => (
is => 'ro',
);
sub test {
my $self = shift;
return $self->foo;
}
sub forward_to_me {
my ( $self, $c ) = @_;
$c->response->output( $self->foo );
}
1;
# Methods can be a request step
$c->forward(qw/MyApp::Model::Something forward_to_me/);
# Or just methods
print $c->comp('MyApp::Model::Something')->test;
print $c->comp('MyApp::Model::Something')->foo;
=head1 DESCRIPTION
This is the universal base class for Catalyst components
(Model/View/Controller).
It provides you with a generic new() for component construction through Catalyst's
component loader with config() support and a process() method placeholder.
B<Note> that calling C<< $self->config >> inside a component is strongly
not recommended - the correctly merged config should have already been
passed to the constructor and stored in attributes - accessing
the config accessor directly from an instance is likely to get the
wrong values (as it only holds the class wide config, not things loaded
from the config file!)
=cut
__PACKAGE__->mk_classdata('_plugins');
__PACKAGE__->mk_classdata('_config');
has catalyst_component_name => ( is => 'ro' ); # Cannot be required => 1 as context
# class @ISA component - HATE
# Make accessor callable as a class method, as we need to call setup_actions
# on the application class, which we don't have an instance of, ewwwww
# Also, naughty modules like Catalyst::View::JSON try to write to _everything_,
# so spit a warning, ignore that (and try to do the right thing anyway) here..
around catalyst_component_name => sub {
my ($orig, $self) = (shift, shift);
Carp::cluck("Tried to write to the catalyst_component_name accessor - is your component broken or just mad? (Write ignored - using default value.)") if scalar @_;
blessed($self) ? $self->$orig() || blessed($self) : $self;
};
sub BUILDARGS {
my $class = shift;
my $args = {};
if (@_ == 1) {
$args = $_[0] if ref($_[0]) eq 'HASH';
} elsif (@_ == 2) { # is it ($app, $args) or foo => 'bar' ?
if (blessed($_[0])) {
$args = $_[1] if ref($_[1]) eq 'HASH';
} elsif (is_class_loaded($_[0]) &&
$_[0]->isa('Catalyst') && ref($_[1]) eq 'HASH') {
$args = $_[1];
} else {
$args = +{ @_ };
}
} elsif (@_ % 2 == 0) {
$args = +{ @_ };
}
return $class->merge_config_hashes( $class->config, $args );
}
sub COMPONENT {
my ( $class, $c ) = @_;
# Temporary fix, some components does not pass context to constructor
my $arguments = ( ref( $_[-1] ) eq 'HASH' ) ? $_[-1] : {};
if ( my $next = $class->next::can ) {
my ($next_package) = Class::MOP::get_code_info($next);
warn "There is a COMPONENT method resolving after Catalyst::Component in ${next_package}.\n";
warn "This behavior can no longer be supported, and so your application is probably broken.\n";
warn "Your linearized isa hierarchy is: " . join(', ', @{ mro::get_linear_isa($class) }) . "\n";
warn "Please see perldoc Catalyst::Upgrading for more information about this issue.\n";
}
return $class->new($c, $arguments);
}
sub config {
my $self = shift;
# Uncomment once sane to do so
#Carp::cluck("config method called on instance") if ref $self;
my $config = $self->_config || {};
if (@_) {
my $newconfig = { %{@_ > 1 ? {@_} : $_[0]} };
$self->_config(
$self->merge_config_hashes( $config, $newconfig )
);
} else {
# this is a bit of a kludge, required to make
# __PACKAGE__->config->{foo} = 'bar';
# work in a subclass.
# TODO maybe this should be a ClassData option?
my $class = blessed($self) || $self;
my $meta = find_meta($class);
unless (${ $meta->get_or_add_package_symbol('$_config') }) {
# Call merge_hashes to ensure we deep copy the parent
# config onto the subclass
$self->_config( Catalyst::Utils::merge_hashes($config, {}) );
}
}
return $self->_config;
}
sub merge_config_hashes {
my ( $self, $lefthash, $righthash ) = @_;
return Catalyst::Utils::merge_hashes( $lefthash, $righthash );
}
sub process {
Catalyst::Exception->throw( message => ( ref $_[0] || $_[0] )
. " did not override Catalyst::Component::process" );
}
sub expand_modules {
my ($class, $component) = @_;
return Devel::InnerPackage::list_packages( $component );
}
__PACKAGE__->meta->make_immutable;
1;
__END__
=head1 METHODS
=head2 new($app, $arguments)
Called by COMPONENT to instantiate the component; should return an object
to be stored in the application's component hash.
=head2 COMPONENT
C<< my $component_instance = $component->COMPONENT($app, $arguments); >>
If this method is present (as it is on all Catalyst::Component subclasses),
it is called by Catalyst during setup_components with the application class
as $app and any config entry on the application for this component (for example,
in the case of MyApp::Controller::Foo this would be
C<< MyApp->config('Controller::Foo' => \%conf >>).
The arguments are expected to be a hashref and are merged with the
C<< __PACKAGE__->config >> hashref before calling C<< ->new >>
to instantiate the component.
You can override it in your components to do custom construction, using
something like this:
sub COMPONENT {
my ($class, $app, $args) = @_;
$args = $class->merge_config_hashes($class->config, $args);
return $class->new($app, $args);
}
=head2 $c->config
=head2 $c->config($hashref)
=head2 $c->config($key, $value, ...)
Accessor for this component's config hash. Config values can be set as
key value pair, or you can specify a hashref. In either case the keys
will be merged with any existing config settings. Each component in
a Catalyst application has its own config hash.
The component's config hash is merged with any config entry on the
application for this component and passed to C<new()> (as mentioned
above at L</COMPONENT>). The recommended practice to access the merged
config is to use a Moose attribute for each config entry on the
receiving component.
=head2 $c->process()
This is the default method called on a Catalyst component in the dispatcher.
For instance, Views implement this action to render the response body
when you forward to them. The default is an abstract method.
=head2 $c->merge_config_hashes( $hashref, $hashref )
Merges two hashes together recursively, giving right-hand precedence.
Alias for the method in L<Catalyst::Utils>.
=head2 $c->expand_modules( $setup_component_config )
Return a list of extra components that this component has created. By default,
it just looks for a list of inner packages of this component
=cut
=head1 OPTIONAL METHODS
=head2 ACCEPT_CONTEXT($c, @args)
Catalyst components are normally initialized during server startup, either
as a Class or a Instance. However, some components require information about
the current request. To do so, they can implement an ACCEPT_CONTEXT method.
If this method is present, it is called during $c->comp/controller/model/view
with the current $c and any additional args (e.g. $c->model('Foo', qw/bar baz/)
would cause your MyApp::Model::Foo instance's ACCEPT_CONTEXT to be called with
($c, 'bar', 'baz')) and the return value of this method is returned to the
calling code in the application rather than the component itself.
=head1 SEE ALSO
L<Catalyst>, L<Catalyst::Model>, L<Catalyst::View>, L<Catalyst::Controller>.
=head1 AUTHORS
Catalyst Contributors, see Catalyst.pm
=head1 COPYRIGHT
This library is free software. You can redistribute it and/or modify it under
the same terms as Perl itself.
=cut