=head2 What is Catalyst?
Catalyst is an elegant web application framework, extremely flexible
-yet extremely simple. It's similar to Ruby on Rails, Spring (Java),
-and L<Maypole>, upon which it was originally based. Its most important
-design philosphy is to provide easy access to all the tools you need
-to develop web applications, with few restrictions on how you need to
-use these tools. However, this does mean that it is always possible to
-do things in a different way. Other web frameworks are B<initially>
-simpler to use, but achieve this by locking the programmer into a
-single set of tools. Catalyst's emphasis on flexibility means that you
-have to think more to use it. We view this as a feature. For example,
-this leads to Catalyst being more suited to system integration tasks
-than other web frameworks.
+yet extremely simple. It's similar to Ruby on Rails, Spring (Java), and
+L<Maypole|Maypole>, upon which it was originally based. Its most
+important design philosphy is to provide easy access to all the tools
+you need to develop web applications, with few restrictions on how you
+need to use these tools. However, this does mean that it is always
+possible to do things in a different way. Other web frameworks are
+I<initially> simpler to use, but achieve this by locking the programmer
+into a single set of tools. Catalyst's emphasis on flexibility means
+that you have to think more to use it. We view this as a feature. For
+example, this leads to Catalyst being more suited to system integration
+tasks than other web frameworks.
=head3 MVC
Now http://localhost:3000/hello prints "Hello World!".
+Note that actions with the C< :Local > attribute are equivalent to
+using a C<:Path('/action_name') > attribute (note the leading slash).
+So our action could be equivalently:
+
+ sub hello : Path('/hello') {
+ my ( $self, $context ) = @_;
+ $context->response->body('Hello World!');
+ }
+
+
=item * B<Support for CGI, mod_perl, Apache::Request, FastCGI>
Use L<Catalyst::Engine::Apache> or L<Catalyst::Engine::CGI>. Other
Catalyst doesn't enforce anything. See L<Catalyst::Manual::About> for
a general discussion of these issues.
-All components must inherit from L<Catalyst::Base>, which provides a
-simple class structure and some common class methods like C<config> and
-C<new> (constructor).
+Model, View and Controller components must inherit from L<Catalyst::Model>,
+L<Catalyst::View> and L<Catalyst::Controller>, respectively. These, in turn, inherit
+from L<Catalyst::Component> which provides a simple class structure and some
+common class methods like C<config> and C<new> (constructor).
package MyApp::Controller::Catalog;
use strict;
- use base 'Catalyst::Base';
+ use base 'Catalyst::Controller';
__PACKAGE__->config( foo => 'bar' );
INSERT INTO foo (data) VALUES ('TEST!');
- % sqlite /tmp/myapp.db < myapp.sql
+ % sqlite3 /tmp/myapp.db < myapp.sql
Now we can create a DBIC::Schema model for this database.
script/myapp_create.pl model MyModel DBIC::Schema MySchema create=static 'dbi:SQLite:/tmp/myapp.db'
-L<DBIx::Class::Schema::Loader> automatically loads table layouts and
-relationships, and converts them into a static schema definition C<MySchema>,
-which you can edit later.
+L<DBIx::Class::Schema::Loader> can automaticall load table layouts and
+relationships, and convert them into a static schema definition
+C<MySchema>, which you can edit later.
Use the stash to pass data to your templates.
# Sets the actions in this controller to be registered with no prefix
# so they function identically to actions created in MyApp.pm
__PACKAGE__->config->{namespace} = '';
- sub default : Private {
+ sub default : Path {
my ( $self, $context ) = @_;
- $context->response->body('Catalyst rocks!');
+ $context->response->status(404);
+ $context->response->body('404 not found');
}
1;
explanation of the pre-defined meaning of Catalyst component class
names.
+Note that actions with the C< :Local > attribute are equivalent to the
+<:Path('action_name') > so sub foo : Local { } is equivalent to -
+
+ sub foo : Path('foo') { }
+
=item * B<Chained>
Catalyst also provides a method to build and dispatch chains of actions,
sub foo : Private { }
Matches no URL, and cannot be executed by requesting a URL that
-corresponds to the action key. Private actions can be executed only
-inside a Catalyst application, by calling the C<forward> method:
+corresponds to the action key. Catalyst's :Private attribute is
+exclusive and doesn't work with other attributes (so will not work
+combined with Path or Chained attributes). With the exception of the
+C< index >, C< auto > and C< default > actions, Private actions can
+only be executed from inside a Catalyst application, by calling the
+C<forward> or C<detach> methods:
$c->forward('foo');
+ # or
+ $c->detach('foo');
See L</Flow Control> for a full explanation of C<forward>. Note that, as
discussed there, when forwarding from another component, you must use
=over 4
-=item * B<default : Private>
+=item * B<default : Path>
Called when no other action matches. Could be used, for example, for
displaying a generic frontpage for the main app, or an error page for
individual controllers.
-If C<default> isn't acting how you would expect, look at using a
-L</Literal> C<Path> action (with an empty path string). The difference
-is that C<Path> takes arguments relative from the namespace and
-C<default> I<always> takes arguments relative from the root, regardless
-of what controller it's in. Indeed, this is now the recommended way of
-handling default situations; the C<default> private controller should
-be considered deprecated.
-=item * B<index : Private>
+=item * B<index : Path : Args (0) >
-C<index> is much like C<default> except that it takes no arguments
-and it is weighted slightly higher in the matching process. It is
-useful as a static entry point to a controller, e.g. to have a static
-welcome page. Note that it's also weighted higher than Path.
+C<index> is much like C<default> except that it takes no arguments and
+it is weighted slightly higher in the matching process. It is useful
+as a static entry point to a controller, e.g. to have a static welcome
+page. Note that it's also weighted higher than Path. Actually the sub
+name C<index> can be called anything you want. The sub attributes are
+what determines the behaviour of the action.
=item * B<begin : Private>
Package MyApp::Controller::Foo;
sub begin : Private { }
- sub default : Private { }
+ sub default : Path { }
sub auto : Private { }
You can define built-in private actions within your controllers as
Mailing lists:
- http://lists.rawmode.org/mailman/listinfo/catalyst
- http://lists.rawmode.org/mailman/listinfo/catalyst-dev
+ http://lists.scsys.co.uk/mailman/listinfo/catalyst
+ http://lists.scsys.co.uk/mailman/listinfo/catalyst-dev
=head1 AUTHOR
projects / catagits/Catalyst-Manual.git / blobdiff