NAME Catalyst - The Elegant MVC Web Application Framework SYNOPSIS # use the helper to start a new application catalyst.pl MyApp # add models, views, controllers script/myapp_create.pl model Database DBIC dbi:SQLite:/path/to/db script/myapp_create.pl view TT TT script/myapp_create.pl controller Search # built in testserver -- use -r to restart automatically on changes script/myapp_server.pl # command line testing interface script/myapp_test.pl /yada ### in MyApp.pm use Catalyst qw/-Debug/; # include plugins here as well sub foo : Global { # called for /foo, /foo/1, /foo/1/2, etc. my ( $self, $c, @args ) = @_; # args are qw/1 2/ for /foo/1/2 $c->stash->{template} = 'foo.tt'; # set the template # lookup something from db -- stash vars are passed to TT $c->stash->{data} = MyApp::Model::Database::Foo->search( { country => $args[0] } ); if ( $c->req->params->{bar} ) { # access GET or POST parameters $c->forward( 'bar' ); # process another action # do something else after forward returns } } # The foo.tt TT template can use the stash data from the database [% WHILE (item = data.next) %] [% item.foo %] [% END %] # called for /bar/of/soap, /bar/of/soap/10, etc. sub bar : Path('/bar/of/soap') { ... } # called for all actions, from the top-most controller downwards sub auto : Private { my ( $self, $c ) = @_; if ( !$c->user ) { $c->res->redirect( '/login' ); # require login return 0; # abort request and go immediately to end() } return 1; # success; carry on to next action } # called after all actions are finished sub end : Private { my ( $self, $c ) = @_; if ( scalar @{ $c->error } ) { ... } # handle errors return if $c->res->body; # already have a response $c->forward( 'MyApp::View::TT' ); # render template } ### in MyApp/Controller/Foo.pm # called for /foo/bar sub bar : Local { ... } # called for /blargle sub blargle : Global { ... } # an index action matches /foo, but not /foo/1, etc. sub index : Private { ... } ### in MyApp/Controller/Foo/Bar.pm # called for /foo/bar/baz sub baz : Local { ... } # first MyApp auto is called, then Foo auto, then this sub auto : Private { ... } # powerful regular expression paths are also possible sub details : Regex('^product/(\w+)/details$') { my ( $self, $c ) = @_; # extract the (\w+) from the URI my $product = $c->req->snippets->[0]; } See Catalyst::Manual::Intro for additional information. DESCRIPTION The key concept of Catalyst is DRY (Don't Repeat Yourself). See Catalyst::Manual for more documentation. Catalyst plugins can be loaded by naming them as arguments to the "use Catalyst" statement. Omit the "Catalyst::Plugin::" prefix from the plugin name, i.e., "Catalyst::Plugin::My::Module" becomes "My::Module". use Catalyst qw/My::Module/; Special flags like "-Debug" and "-Engine" can also be specified as arguments when Catalyst is loaded: use Catalyst qw/-Debug My::Module/; The position of plugins and flags in the chain is important, because they are loaded in exactly the order in which they appear. The following flags are supported: -Debug Enables debug output. -Engine Forces Catalyst to use a specific engine. Omit the "Catalyst::Engine::" prefix of the engine name, i.e.: use Catalyst qw/-Engine=CGI/; -Home Forces Catalyst to use a specific home directory, e.g.: use Catalyst qw[-Home=/usr/sri]; -Log Specifies log level. METHODS Information about the current request $c->action Returns a Catalyst::Action object for the current action, which stringifies to the action name. See Catalyst::Action. $c->namespace Returns the namespace of the current action, i.e., the uri prefix corresponding to the controller of the current action. For example: # in Controller::Foo::Bar $c->namespace; # returns 'foo/bar'; $c->request $c->req Returns the current Catalyst::Request object. See Catalyst::Request. Processing and response to the current request $c->forward( $action [, \@arguments ] ) $c->forward( $class, $method, [, \@arguments ] ) Forwards processing to a private action. If you give a class name but no method, "process()" is called. You may also optionally pass arguments in an arrayref. The action will receive the arguments in @_ and "$c->req->args". Upon returning from the function, "$c->req->args" will be restored to the previous values. $c->forward('/foo'); $c->forward('index'); $c->forward(qw/MyApp::Model::CDBI::Foo do_stuff/); $c->forward('MyApp::View::TT'); $c->detach( $action [, \@arguments ] ) $c->detach( $class, $method, [, \@arguments ] ) The same as "forward", but doesn't return. $c->error $c->error($error, ...) $c->error($arrayref) Returns an arrayref containing error messages. If Catalyst encounters an error while processing a request, it stores the error in $c->error. This method should not be used to store non-fatal error messages. my @error = @{ $c->error }; Add a new error. $c->error('Something bad happened'); Clear errors. You probably don't want to clear the errors unless you are implementing a custom error screen. $c->error(0); $c->response $c->res Returns the current Catalyst::Response object. $c->stash Returns a hashref to the stash, which may be used to store data and pass it between components during a request. You can also set hash keys by passing arguments. The stash is automatically sent to the view. The stash is cleared at the end of a request; it cannot be used for persistent storage. $c->stash->{foo} = $bar; $c->stash( { moose => 'majestic', qux => 0 } ); $c->stash( bar => 1, gorch => 2 ); # equivalent to passing a hashref # stash is automatically passed to the view for use in a template $c->forward( 'MyApp::V::TT' ); $c->state Contains the return value of the last executed action. Component Accessors $c->comp($name) $c->component($name) Gets a component object by name. This method is no longer recommended, unless you want to get a specific component by full class. "$c->controller", "$c->model", and "$c->view" should be used instead. $c->controller($name) Gets a Catalyst::Controller instance by name. $c->controller('Foo')->do_stuff; $c->model($name) Gets a Catalyst::Model instance by name. $c->model('Foo')->do_stuff; $c->view($name) Gets a Catalyst::View instance by name. $c->view('Foo')->do_stuff; Class data and helper classes $c->config Returns or takes a hashref containing the application's configuration. __PACKAGE__->config({ db => 'dsn:SQLite:foo.db' }); $c->debug Overload to enable debug messages (same as -Debug option). $c->dispatcher Returns the dispatcher instance. Stringifies to class name. See Catalyst::Dispatcher. $c->engine Returns the engine instance. Stringifies to the class name. See Catalyst::Engine. $c->log Returns the logging object instance. Unless it is already set, Catalyst sets this up with a Catalyst::Log object. To use your own log class: $c->log( MyLogger->new ); $c->log->info( 'Now logging with my own logger!' ); Your log class should implement the methods described in the Catalyst::Log man page. Utility methods $c->path_to(@path) Merges @path with "$c->config->{home}" and returns a Path::Class object. For example: $c->path_to( 'db', 'sqlite.db' ); $c->plugin( $name, $class, @args ) Helper method for plugins. It creates a classdata accessor/mutator and loads and instantiates the given class. MyApp->plugin( 'prototype', 'HTML::Prototype' ); $c->prototype->define_javascript_functions; MyApp->setup Initializes the dispatcher and engine, loads any plugins, and loads the model, view, and controller components. You may also specify an array of plugins to load here, if you choose to not load them in the "use Catalyst" line. MyApp->setup; MyApp->setup( qw/-Debug/ ); $c->uri_for( $path, [ @args ] ) Merges path with "$c->request->base" for absolute uri's and with "$c->namespace" for relative uri's, then returns a normalized URI object. If any args are passed, they are added at the end of the path. $c->welcome_message Returns the Catalyst welcome HTML page. INTERNAL METHODS These methods are not meant to be used by end users. $c->components Returns a hash of components. $c->context_class Returns or sets the context class. $c->counter Returns a hashref containing coderefs and execution counts (needed for deep recursion detection). $c->depth Returns the number of actions on the current internal execution stack. $c->dispatch Dispatches a request to actions. $c->dispatcher_class Returns or sets the dispatcher class. $c->dump_these Returns a list of 2-element array references (name, structure) pairs that will be dumped on the error page in debug mode. $c->engine_class Returns or sets the engine class. $c->execute( $class, $coderef ) Execute a coderef in given class and catch exceptions. Errors are available via $c->error. $c->finalize Finalizes the request. $c->finalize_body Finalizes body. $c->finalize_cookies Finalizes cookies. $c->finalize_error Finalizes error. $c->finalize_headers Finalizes headers. $c->finalize_output An alias for finalize_body. $c->finalize_read Finalizes the input after reading is complete. $c->finalize_uploads Finalizes uploads. Cleans up any temporary files. $c->get_action( $action, $namespace ) Gets an action in a given namespace. $c->get_actions( $action, $namespace ) Gets all actions of a given name in a namespace and all parent namespaces. handle_request( $class, @arguments ) Called to handle each HTTP request. $c->prepare( @arguments ) Creates a Catalyst context from an engine-specific request (Apache, CGI, etc.). $c->prepare_action Prepares action. $c->prepare_body Prepares message body. $c->prepare_body_chunk( $chunk ) Prepares a chunk of data before sending it to HTTP::Body. $c->prepare_body_parameters Prepares body parameters. $c->prepare_connection Prepares connection. $c->prepare_cookies Prepares cookies. $c->prepare_headers Prepares headers. $c->prepare_parameters Prepares parameters. $c->prepare_path Prepares path and base. $c->prepare_query_parameters Prepares query parameters. $c->prepare_read Prepares the input for reading. $c->prepare_request Prepares the engine request. $c->prepare_uploads Prepares uploads. $c->prepare_write Prepares the output for writing. $c->request_class Returns or sets the request class. $c->response_class Returns or sets the response class. $c->read( [$maxlength] ) Reads a chunk of data from the request body. This method is designed to be used in a while loop, reading $maxlength bytes on every call. $maxlength defaults to the size of the request if not specified. You have to set "MyApp->config->{parse_on_demand}" to use this directly. $c->run Starts the engine. $c->set_action( $action, $code, $namespace, $attrs ) Sets an action in a given namespace. $c->setup_actions($component) Sets up actions for a component. $c->setup_components Sets up components. $c->setup_dispatcher Sets up dispatcher. $c->setup_engine Sets up engine. $c->setup_home Sets up the home directory. $c->setup_log Sets up log. $c->setup_plugins Sets up plugins. $c->stack Returns the stack. $c->write( $data ) Writes $data to the output stream. When using this method directly, you will need to manually set the "Content-Length" header to the length of your output data, if known. version Returns the Catalyst version number. Mostly useful for "powered by" messages in template systems. INTERNAL ACTIONS Catalyst uses internal actions like "_DISPATCH", "_BEGIN", "_AUTO", "_ACTION", and "_END". These are by default not shown in the private action table, but you can make them visible with a config parameter. MyApp->config->{show_internal_actions} = 1; CASE SENSITIVITY By default Catalyst is not case sensitive, so "MyApp::C::FOO::Bar" is mapped to "/foo/bar". You can activate case sensitivity with a config parameter. MyApp->config->{case_sensitive} = 1; This causes "MyApp::C::Foo::Bar" to map to "/Foo/Bar". ON-DEMAND PARSER The request body is usually parsed at the beginning of a request, but if you want to handle input yourself or speed things up a bit, you can enable on-demand parsing with a config parameter. MyApp->config->{parse_on_demand} = 1; PROXY SUPPORT Many production servers operate using the common double-server approach, with a lightweight frontend web server passing requests to a larger backend server. An application running on the backend server must deal with two problems: the remote user always appears to be 127.0.0.1 and the server's hostname will appear to be "localhost" regardless of the virtual host that the user connected through. Catalyst will automatically detect this situation when you are running the frontend and backend servers on the same machine. The following changes are made to the request. $c->req->address is set to the user's real IP address, as read from the HTTP X-Forwarded-For header. The host value for $c->req->base and $c->req->uri is set to the real host, as read from the HTTP X-Forwarded-Host header. Obviously, your web server must support these headers for this to work. In a more complex server farm environment where you may have your frontend proxy server(s) on different machines, you will need to set a configuration option to tell Catalyst to read the proxied data from the headers. MyApp->config->{using_frontend_proxy} = 1; If you do not wish to use the proxy support at all, you may set: MyApp->config->{ignore_frontend_proxy} = 1; THREAD SAFETY Catalyst has been tested under Apache 2's threading mpm_worker, mpm_winnt, and the standalone forking HTTP server on Windows. We believe the Catalyst core to be thread-safe. If you plan to operate in a threaded environment, remember that all other modules you are using must also be thread-safe. Some modules, most notably DBD::SQLite, are not thread-safe. SUPPORT IRC: Join #catalyst on irc.perl.org. Mailing Lists: http://lists.rawmode.org/mailman/listinfo/catalyst http://lists.rawmode.org/mailman/listinfo/catalyst-dev Web: http://catalyst.perl.org Wiki: http://dev.catalyst.perl.org SEE ALSO Task::Catalyst - All you need to start with Catalyst Catalyst::Manual - The Catalyst Manual Catalyst::Component, Catalyst::Base - Base classes for components Catalyst::Engine - Core engine Catalyst::Log - Log class. Catalyst::Request - Request object Catalyst::Response - Response object Catalyst::Test - The test suite. CREDITS Andy Grundman Andy Wardley Andreas Marienborg Andrew Bramble Andrew Ford Andrew Ruthven Arthur Bergman Autrijus Tang Brian Cassidy Christian Hansen Christopher Hicks Dan Sully Danijel Milicevic David Kamholz David Naughton Drew Taylor Gary Ashton Jones Geoff Richards Jesse Sheidlower Jesse Vincent Jody Belka Johan Lindstrom Juan Camacho Leon Brocard Marcus Ramberg Matt S Trout Robert Sedlacek Sam Vilain Sascha Kiefer Tatsuhiko Miyagawa Ulf Edvinsson Yuval Kogman AUTHOR Sebastian Riedel, "sri@oook.de" LICENSE This library is free software, you can redistribute it and/or modify it under the same terms as Perl itself.