3 Catalyst::Manual::Cookbook - Cooking with Catalyst
7 Yummy code like your mum used to bake!
13 These recipes cover some basic stuff that is worth knowing for
16 =head2 Delivering a Custom Error Page
18 By default, Catalyst will display its own error page whenever it
19 encounters an error in your application. When running under C<-Debug>
20 mode, the error page is a useful screen including the error message
21 and L<Data::Dump> output of the relevant parts of the C<$c> context
22 object. When not in C<-Debug>, users see a simple "Please come back
25 To use a custom error page, use a special C<end> method to
26 short-circuit the error processing. The following is an example; you
27 might want to adjust it further depending on the needs of your
28 application (for example, any calls to C<fillform> will probably need
29 to go into this C<end> method; see L<Catalyst::Plugin::FillInForm>).
32 my ( $self, $c ) = @_;
34 if ( scalar @{ $c->error } ) {
35 $c->stash->{errors} = $c->error;
36 for my $error ( @{ $c->error } ) {
37 $c->log->error($error);
39 $c->stash->{template} = 'errors.tt';
40 $c->forward('MyApp::View::TT');
44 return 1 if $c->response->status =~ /^3\d\d$/;
45 return 1 if $c->response->body;
47 unless ( $c->response->content_type ) {
48 $c->response->content_type('text/html; charset=utf-8');
51 $c->forward('MyApp::View::TT');
54 You can manually set errors in your code to trigger this page by calling
56 $c->error( 'You broke me!' );
58 =head2 Disable statistics
60 Just add this line to your application class if you don't want those
61 nifty statistics in your debug messages.
63 sub Catalyst::Log::info { }
65 =head2 Enable debug status in the environment
67 Normally you enable the debugging info by adding the C<-Debug> flag to
68 your C<use Catalyst> statement . However, you can also enable it using
69 environment variable, so you can (for example) get debug info without
70 modifying your application scripts. Just set C<CATALYST_DEBUG> or
71 C<E<lt>MYAPPE<gt>_DEBUG> to a true value.
75 When you have your users identified, you will want to somehow remember
76 that fact, to save them from having to identify themselves for every
77 single page. One way to do this is to send the username and password
78 parameters in every single page, but that's ugly, and won't work for
81 Sessions are a method of saving data related to some transaction, and
82 giving the whole collection a single ID. This ID is then given to the
83 user to return to us on every page they visit while logged in. The
84 usual way to do this is using a browser cookie.
86 Catalyst uses two types of plugins to represent sessions:
90 A State module is used to keep track of the state of the session
91 between the users browser, and your application.
93 A common example is the Cookie state module, which sends the browser a
94 cookie containing the session ID. It will use default value for the
95 cookie name and domain, so will "just work" when used.
99 A Store module is used to hold all the data relating to your session,
100 for example the users ID, or the items for their shopping cart. You
101 can store data in memory (FastMmap), in a file (File) or in a database
104 =head3 Authentication magic
106 If you have included the session modules in your application, the
107 Authentication modules will automagically use your session to save and
108 retrieve the user data for you.
110 =head3 Using a session
112 Once the session modules are loaded, the session is available as C<<
113 $c->session >>, and can be writen to and read from as a simple hash
120 use namespace::autoclean;
124 Session::Store::FastMmap
125 Session::State::Cookie
130 package MyApp::Controller::Foo;
132 use namespace::autoclean;
133 BEGIN { extends 'Catalyst::Controller' };
134 ## Write data into the session
136 sub add_item : Local {
137 my ( $self, $c ) = @_;
139 my $item_id = $c->req->params->{item};
141 push @{ $c->session->{items} }, $item_id;
145 ## A page later we retrieve the data from the session:
147 sub get_items : Local {
148 my ( $self, $c ) = @_;
150 $c->stash->{items_to_display} = $c->session->{items};
155 =head3 More information
157 L<http://search.cpan.org/dist/Catalyst-Plugin-Session>
159 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-Cookie>
161 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-URI>
163 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-FastMmap>
165 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-File>
167 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-DBI>
169 =head2 Configure your application
171 You configure your application with the C<config> method in your
172 application class. This can be hard-coded, or brought in from a
173 separate configuration file.
175 =head3 Using Config::General
177 L<Config::General|Config::General> is a method for creating flexible
178 and readable configuration files. It's a great way to keep your
179 Catalyst application configuration in one easy-to-understand location.
181 Now create C<myapp.conf> in your application home:
185 # session; perldoc Catalyst::Plugin::Session::FastMmap
189 storage /tmp/myapp.session
192 # emails; perldoc Catalyst::Plugin::Email
193 # this passes options as an array :(
197 This is equivalent to:
199 # configure base package
200 __PACKAGE__->config( name => MyApp );
201 # configure authentication
202 __PACKAGE__->config->{authentication} = {
203 user_class => 'MyApp::Model::MyDB::Customer',
207 __PACKAGE__->config->{session} = {
211 # configure email sending
212 __PACKAGE__->config->{email} = [qw/SMTP localhost/];
214 See also L<Config::General|Config::General>.
216 =head1 Skipping your VCS's directories
218 Catalyst uses Module::Pluggable to load Models, Views, and Controllers.
219 Module::Pluggable will scan through all directories and load modules
220 it finds. Sometimes you might want to skip some of these directories,
221 for example when your version control system makes a subdirectory with
222 meta-information in every version-controlled directory. While
223 Catalyst skips subversion and CVS directories already, there are other
224 source control systems. Here is the configuration you need to add
225 their directories to the list to skip.
227 You can make Catalyst skip these directories using the Catalyst config:
229 # Configure the application
232 setup_components => { except => qr/SCCS/ },
235 See the Module::Pluggable manual page for more information on B<except>
238 =head1 Users and Access Control
240 Most multiuser, and some single-user web applications require that
241 users identify themselves, and the application is often required to
242 define those roles. The recipes below describe some ways of doing
245 =head2 Authentication (logging in)
247 This is extensively covered in other documentation; see in particular
248 L<Catalyst::Plugin::Authentication> and the Authentication chapter
249 of the Tutorial at L<Catalyst::Manual::Tutorial::06_Authorization>.
251 =head2 Pass-through login (and other actions)
253 An easy way of having assorted actions that occur during the processing
254 of a request that are orthogonal to its actual purpose - logins, silent
255 commands etc. Provide actions for these, but when they're required for
256 something else fill e.g. a form variable __login and have a sub begin
259 sub begin : Private {
261 foreach my $action (qw/login docommand foo bar whatever/) {
262 if ($c->req->params->{"__${action}"}) {
263 $c->forward($action);
268 =head2 Authentication/Authorization
270 This is done in several steps:
276 Getting the user to identify themselves, by giving you some piece of
277 information known only to you and the user. Then you can assume that
278 the user is who they say they are. This is called B<credential
283 Making sure the user only accesses functions you want them to
284 access. This is done by checking the verified user's data against your
285 internal list of groups, or allowed persons for the current page.
291 The Catalyst Authentication system is made up of many interacting
292 modules, to give you the most flexibility possible.
294 =head4 Credential verifiers
296 A Credential module tables the user input, and passes it to a Store,
297 or some other system, for verification. Typically, a user object is
298 created by either this module or the Store and made accessible by a
299 C<< $c->user >> call.
303 Password - Simple username/password checking.
304 HTTPD - Checks using basic HTTP auth.
305 TypeKey - Check using the typekey system.
307 =head3 Storage backends
309 A Storage backend contains the actual data representing the users. It
310 is queried by the credential verifiers. Updating the store is not done
311 within this system; you will need to do it yourself.
315 DBIC - Storage using a database via DBIx::Class.
316 Minimal - Storage using a simple hash (for testing).
320 A User object is created by either the storage backend or the
321 credential verifier, and is filled with the retrieved user information.
325 Hash - A simple hash of keys and values.
327 =head3 ACL authorization
329 ACL stands for Access Control List. The ACL plugin allows you to
330 regulate access on a path-by-path basis, by listing which users, or
331 roles, have access to which paths.
333 =head3 Roles authorization
335 Authorization by roles is for assigning users to groups, which can
336 then be assigned to ACLs, or just checked when needed.
340 When you have chosen your modules, all you need to do is call the C<<
341 $c->authenticate >> method. If called with no parameters, it will try to find
342 suitable parameters, such as B<username> and B<password>, or you can
343 pass it these values.
345 =head3 Checking roles
347 Role checking is done by using the C<< $c->check_user_roles >> method.
348 This will check using the currently logged-in user (via C<< $c->user
349 >>). You pass it the name of a role to check, and it returns true if
350 the user is a member.
356 use namespace::autoclean;
357 extends qw/Catalyst/;
365 default_realm => 'test',
370 password_field => 'password',
371 password_type => 'self_check',
382 package MyApp::Controller::Root;
384 use namespace::autoclean;
386 BEGIN { extends 'Catalyst::Controller' }
388 __PACKAGE__->config(namespace => '');
393 if ( my $user = $c->req->params->{user}
394 and my $password = $c->req->param->{password} )
396 if ( $c->authenticate( username => $user, password => $password ) ) {
397 $c->res->body( "hello " . $c->user->name );
407 sub restricted : Local {
408 my ( $self, $c ) = @_;
410 $c->detach("unauthorized")
411 unless $c->check_user_roles( "admin" );
413 # do something restricted here
416 =head3 Using authentication in a testing environment
418 Ideally, to write tests for authentication/authorization code one would
419 first set up a test database with known data, then use
420 L<Test::WWW::Mechanize::Catalyst> to simulate a user logging
421 in. Unfortunately this can be rather awkward, which is why it's a good
422 thing that the authentication framework is so flexible.
424 Instead of using a test database, one can simply change the
425 authentication store to something a bit easier to deal with in a
426 testing environment. Additionally, this has the advantage of not
427 modifying one's database, which can be problematic if one forgets to
428 use the testing instead of production database.
430 Alternatively, if you want to authenticate real users, but not have to
431 worry about their passwords, you can use
432 L<Catalyst::Authentication::Credential::Testing> to force all users to
433 authenticate with a global password.
435 =head3 More information
437 L<Catalyst::Plugin::Authentication> has a longer explanation.
443 Authorization is the step that comes after
444 authentication. Authentication establishes that the user agent is really
445 representing the user we think it's representing, and then authorization
446 determines what this user is allowed to do.
448 =head3 Role Based Access Control
450 Under role based access control each user is allowed to perform any
451 number of roles. For example, at a zoo no one but specially trained
452 personnel can enter the moose cage (Mynd you, møøse bites kan be
453 pretty nasti!). For example:
455 package Zoo::Controller::MooseCage;
457 sub feed_moose : Local {
458 my ( $self, $c ) = @_;
460 $c->model( "Moose" )->eat( $c->req->params->{food} );
463 With this action, anyone can just come into the moose cage and feed
464 the moose, which is a very dangerous thing. We need to restrict this
465 action, so that only a qualified moose feeder can perform that action.
467 The Authorization::Roles plugin lets us perform role based access
468 control checks. Let's load it:
470 use parent qw/Catalyst/;
476 And now our action should look like this:
478 sub feed_moose : Local {
479 my ( $self, $c ) = @_;
481 if ( $c->check_roles( "moose_feeder" ) ) {
482 $c->model( "Moose" )->eat( $c->req->params->{food} );
484 $c->stash->{error} = "unauthorized";
488 This checks C<< $c->user >>, and only if the user has B<all> the roles
489 in the list, a true value is returned.
491 C<check_roles> has a sister method, C<assert_roles>, which throws an
492 exception if any roles are missing.
494 Some roles that might actually make sense in, say, a forum application:
508 each with a distinct task (system administration versus content
511 =head3 Access Control Lists
513 Checking for roles all the time can be tedious and error prone.
515 The Authorization::ACL plugin lets us declare where we'd like checks
516 to be done automatically for us.
518 For example, we may want to completely block out anyone who isn't a
519 C<moose_feeder> from the entire C<MooseCage> controller:
521 Zoo->deny_access_unless( "/moose_cage", [qw/moose_feeder/] );
523 The role list behaves in the same way as C<check_roles>. However, the
524 ACL plugin isn't limited to just interacting with the Roles plugin. We
525 can use a code reference instead. For example, to allow either moose
526 trainers or moose feeders into the moose cage, we can create a more
529 Zoo->deny_access_unless( "/moose_cage", sub {
531 $c->check_roles( "moose_trainer" ) || $c->check_roles( "moose_feeder" );
534 The more specific a role, the earlier it will be checked. Let's say
535 moose feeders are now restricted to only the C<feed_moose> action,
536 while moose trainers get access everywhere:
538 Zoo->deny_access_unless( "/moose_cage", [qw/moose_trainer/] );
539 Zoo->allow_access_if( "/moose_cage/feed_moose", [qw/moose_feeder/]);
541 When the C<feed_moose> action is accessed the second check will be
542 made. If the user is a C<moose_feeder>, then access will be
543 immediately granted. Otherwise, the next rule in line will be tested -
544 the one checking for a C<moose_trainer>. If this rule is not
545 satisfied, access will be immediately denied.
547 Rules applied to the same path will be checked in the order they were
550 Lastly, handling access denial events is done by creating an
551 C<access_denied> private action:
553 sub access_denied : Private {
554 my ( $self, $c, $action ) = @_;
557 This action works much like auto, in that it is inherited across
558 namespaces (not like object oriented code). This means that the
559 C<access_denied> action which is B<nearest> to the action which was
560 blocked will be triggered.
562 If this action does not exist, an error will be thrown, which you can
563 clean up in your C<end> private action instead.
565 Also, it's important to note that if you restrict access to "/" then
566 C<end>, C<default>, etc. will also be restricted.
568 MyApp->acl_allow_root_internals;
570 will create rules that permit access to C<end>, C<begin>, and C<auto> in the
571 root of your app (but not in any other controller).
575 Models are where application data belongs. Catalyst is extremely
576 flexible with the kind of models that it can use. The recipes here
579 =head2 Using existing DBIC (etc.) classes with Catalyst
581 Many people have existing Model classes that they would like to use
582 with Catalyst (or, conversely, they want to write Catalyst models that
583 can be used outside of Catalyst, e.g. in a cron job). It's trivial to
584 write a simple component in Catalyst that slurps in an outside Model:
586 package MyApp::Model::DB;
588 use base qw/Catalyst::Model::DBIC::Schema/;
591 schema_class => 'Some::DBIC::Schema',
592 connect_info => ['dbi:SQLite:foo.db', '', '', {AutoCommit=>1}],
597 and that's it! Now C<Some::DBIC::Schema> is part of your
598 Cat app as C<MyApp::Model::DB>.
600 =head2 DBIx::Class as a Catalyst Model
602 See L<Catalyst::Model::DBIC::Schema>.
604 =head2 Create accessors to preload static data once per server instance
606 When you have data that you want to load just once from the model at
607 startup, instead of for each request, use mk_group_accessors to
608 create accessors and tie them to resultsets in your package that
609 inherits from DBIx::Class::Schema:
612 use base qw/DBIx::Class::Schema/;
613 __PACKAGE__->register_class('RESULTSOURCEMONIKER',
614 'My::Schema::RESULTSOURCE');
615 __PACKAGE__->mk_group_accessors('simple' =>
616 qw(ACCESSORNAME1 ACCESSORNAME2 ACCESSORNAMEn));
619 my ($self, @rest) = @_;
620 $self->next::method(@rest);
621 # $self is now a live My::Schema object, complete with DB connection
623 $self->ACCESSORNAME1([ $self->resultset('RESULTSOURCEMONIKER')->all ]);
624 $self->ACCESSORNAME2([ $self->resultset('RESULTSOURCEMONIKER')->search({ COLUMN => { '<' => '30' } })->all ]);
625 $self->ACCESSORNAMEn([ $self->resultset('RESULTSOURCEMONIKER')->find(1) ]);
630 and now in the controller, you can now access any of these without a
633 $c->stash->{something} = $c->model('My::Schema')->schema->ACCESSORNAME;
638 Unlike SOAP, XMLRPC is a very simple (and elegant) web-services
639 protocol, exchanging small XML messages like these:
644 TE: deflate,gzip;q=0.3
645 Connection: TE, close
649 User-Agent: SOAP::Lite/Perl/0.60
651 Content-Type: text/xml
653 <?xml version="1.0" encoding="UTF-8"?>
655 <methodName>add</methodName>
657 <param><value><int>1</int></value></param>
658 <param><value><int>2</int></value></param>
665 Date: Tue, 20 Dec 2005 07:45:55 GMT
667 Content-Type: text/xml
671 <?xml version="1.0" encoding="us-ascii"?>
674 <param><value><int>3</int></value></param>
678 Now follow these few steps to implement the application:
680 1. Install Catalyst (5.61 or later), Catalyst::Plugin::XMLRPC (0.06 or
681 later) and SOAP::Lite (for XMLRPCsh.pl).
683 2. Create an application framework:
689 3. Add the XMLRPC plugin to MyApp.pm
691 use Catalyst qw/-Debug Static::Simple XMLRPC/;
693 4. Add an API controller
695 % ./script/myapp_create.pl controller API
697 5. Add a XMLRPC redispatch method and an add method with Remote
698 attribute to lib/MyApp/Controller/API.pm
701 my ( $self, $c ) = @_;
706 my ( $self, $c, $a, $b ) = @_;
710 The default action is the entry point for each XMLRPC request. It will
711 redispatch every request to methods with Remote attribute in the same
714 The C<add> method is not a traditional action; it has no private or
715 public path. Only the XMLRPC dispatcher knows it exists.
717 6. That's it! You have built your first web service. Let's test it with
718 XMLRPCsh.pl (part of SOAP::Lite):
720 % ./script/myapp_server.pl
722 % XMLRPCsh.pl http://127.0.0.1:3000/api
723 Usage: method[(parameters)]
725 --- XMLRPC RESULT ---
730 Your return data type is usually auto-detected, but you can easily
731 enforce a specific one.
734 my ( $self, $c, $a, $b ) = @_;
735 return RPC::XML::int->new( $a + $b );
740 Views pertain to the display of your application. As with models,
741 Catalyst is uncommonly flexible. The recipes below are just a start.
743 =head2 Catalyst::View::TT
745 One of the first things you probably want to do when starting a new
746 Catalyst application is set up your View. Catalyst doesn't care how you
747 display your data; you can choose to generate HTML, PDF files, or plain
750 Most Catalyst applications use a template system to generate their HTML,
751 and though there are several template systems available,
752 L<Template Toolkit|Template> is probably the most popular.
754 Once again, the Catalyst developers have done all the hard work, and
755 made things easy for the rest of us. Catalyst::View::TT provides the
756 interface to Template Toolkit, and provides Helpers which let us set it
757 up that much more easily.
759 =head3 Creating your View
761 Catalyst::View::TT provides two different helpers for us to use: TT and
766 Create a basic Template Toolkit View using the provided helper script:
768 script/myapp_create.pl view TT TT
770 This will create lib/MyApp/View/MyView.pm, which is going to be pretty
771 empty to start. However, it sets everything up that you need to get
772 started. You can now define which template you want and forward to your
776 my ( $self, $c ) = @_;
778 $c->stash->{template} = 'hello.tt';
780 $c->forward( $c->view('TT') );
783 In practice you wouldn't do the forwarding manually, but would
784 use L<Catalyst::Action::RenderView>.
788 Although the TT helper does create a functional, working view, you may
789 find yourself having to create the same template files and changing the
790 same options every time you create a new application. The TTSite helper
791 saves us even more time by creating the basic templates and setting some
792 common options for us.
794 Once again, you can use the helper script:
796 script/myapp_create.pl view TT TTSite
798 This time, the helper sets several options for us in the generated View.
800 __PACKAGE__->config({
801 CATALYST_VAR => 'Catalyst',
803 MyApp->path_to( 'root', 'src' ),
804 MyApp->path_to( 'root', 'lib' )
806 PRE_PROCESS => 'config/main',
807 WRAPPER => 'site/wrapper',
808 ERROR => 'error.tt2',
816 INCLUDE_PATH defines the directories that Template Toolkit should search
817 for the template files.
821 PRE_PROCESS is used to process configuration options which are common to
826 WRAPPER is a file which is processed with each template, usually used to
827 easily provide a common header and footer for every page.
831 In addition to setting these options, the TTSite helper also created the
832 template and config files for us! In the 'root' directory, you'll notice
833 two new directories: src and lib.
835 Several configuration files in root/lib/config are called by PRE_PROCESS.
837 The files in root/lib/site are the site-wide templates, called by
838 WRAPPER, and display the html framework, control the layout, and provide
839 the templates for the header and footer of your page. Using the template
840 organization provided makes it much easier to standardize pages and make
841 changes when they are (inevitably) needed.
843 The template files that you will create for your application will go
844 into root/src, and you don't need to worry about putting the the <html>
845 or <head> sections; just put in the content. The WRAPPER will the rest
846 of the page around your template for you.
851 Of course, having the template system include the header and footer for
852 you isn't all that we want our templates to do. We need to be able to
853 put data into our templates, and have it appear where and how we want
854 it, right? That's where the stash comes in.
856 In our controllers, we can add data to the stash, and then access it
857 from the template. For instance:
860 my ( $self, $c ) = @_;
862 $c->stash->{name} = 'Adam';
864 $c->stash->{template} = 'hello.tt';
866 $c->forward( $c->view('TT') );
871 <strong>Hello, [% name %]!</strong>
873 When you view this page, it will display "Hello, Adam!"
875 All of the information in your stash is available, by its name/key, in
876 your templates. And your data don't have to be plain, old, boring
877 scalars. You can pass array references and hash references, too.
882 my ( $self, $c ) = @_;
884 $c->stash->{names} = [ 'Adam', 'Dave', 'John' ];
886 $c->stash->{template} = 'hello.tt';
888 $c->forward( $c->view('TT') );
893 [% FOREACH name IN names %]
894 <strong>Hello, [% name %]!</strong><br />
897 This allowed us to loop through each item in the arrayref, and display a
898 line for each name that we have.
900 This is the most basic usage, but Template Toolkit is quite powerful,
901 and allows you to truly keep your presentation logic separate from the
902 rest of your application.
906 One of my favorite things about Catalyst is the ability to move an
907 application around without having to worry that everything is going to
908 break. One of the areas that used to be a problem was with the http
909 links in your template files. For example, suppose you have an
910 application installed at http://www.domain.com/Calendar. The links point
911 to "/Calendar", "/Calendar/2005", "/Calendar/2005/10", etc. If you move
912 the application to be at http://www.mydomain.com/Tools/Calendar, then
913 all of those links will suddenly break.
915 That's where $c->uri_for() comes in. This function will merge its
916 parameters with either the base location for the app, or its current
917 namespace. Let's take a look at a couple of examples.
919 In your template, you can use the following:
921 <a href="[% c.uri_for('/login') %]">Login Here</a>
923 Although the parameter starts with a forward slash, this is relative
924 to the application root, not the webserver root. This is important to
925 remember. So, if your application is installed at
926 http://www.domain.com/Calendar, then the link would be
927 http://www.mydomain.com/Calendar/Login. If you move your application
928 to a different domain or path, then that link will still be correct.
932 <a href="[% c.uri_for('2005','10', '24') %]">October, 24 2005</a>
934 The first parameter does NOT have a forward slash, and so it will be
935 relative to the current namespace. If the application is installed at
936 http://www.domain.com/Calendar. and if the template is called from
937 MyApp::Controller::Display, then the link would become
938 http://www.domain.com/Calendar/Display/2005/10/24.
940 If you want to link to a parent uri of your current namespace you can
941 prefix the arguments with multiple '../':
943 <a href="[% c.uri_for('../../view', stashed_object.id) %]">User view</a>
945 Once again, this allows you to move your application around without
946 having to worry about broken links. But there's something else, as
947 well. Since the links are generated by uri_for, you can use the same
948 template file by several different controllers, and each controller
949 will get the links that its supposed to. Since we believe in Don't
950 Repeat Yourself, this is particularly helpful if you have common
951 elements in your site that you want to keep in one file.
955 L<http://search.cpan.org/perldoc?Catalyst>
957 L<http://search.cpan.org/perldoc?Catalyst%3A%3AView%3A%3ATT>
959 L<http://search.cpan.org/perldoc?Template>
961 =head2 Adding RSS feeds
963 Adding RSS feeds to your Catalyst applications is simple. We'll see two
964 different approaches here, but the basic premise is that you forward to
965 the normal view action first to get the objects, then handle the output
968 =head3 Using XML::Feed
970 Assuming we have a C<view> action that populates
971 'entries' with some DBIx::Class iterator, the code would look something
976 $c->forward('view'); # get the entries
978 my $feed = XML::Feed->new('RSS');
979 $feed->title( $c->config->{name} . ' RSS Feed' );
980 $feed->link( $c->req->base ); # link to the site.
981 $feed->description('Catalyst advent calendar'); Some description
983 # Process the entries
984 while( my $entry = $c->stash->{entries}->next ) {
985 my $feed_entry = XML::Feed::Entry->new('RSS');
986 $feed_entry->title($entry->title);
987 $feed_entry->link( $c->uri_for($entry->link) );
988 $feed_entry->issued( DateTime->from_epoch(epoch => $entry->created) );
989 $feed->add_entry($feed_entry);
991 $c->res->body( $feed->as_xml );
994 With this approach you're
995 pretty sure to get something that validates.
997 Note that for both of the above approaches, you'll need to set the
998 content type like this:
1000 $c->res->content_type('application/rss+xml');
1004 You could generalize the second variant easily by replacing 'RSS' with a
1005 variable, so you can generate Atom feeds with the same code.
1007 Now, go ahead and make RSS feeds for all your stuff. The world *needs*
1008 updates on your goldfish!
1010 =head2 Forcing the browser to download content
1012 Sometimes you need your application to send content for download. For
1013 example, you can generate a comma-separated values (CSV) file for your
1014 users to download and import into their spreadsheet program.
1016 Let's say you have an C<Orders> controller which generates a CSV file
1017 in the C<export> action (i.e., C<http://localhost:3000/orders/export>):
1019 sub export : Local Args(0) {
1020 my ( $self, $c ) = @_;
1022 # In a real application, you'd generate this from the database
1023 my $csv = "1,5.99\n2,29.99\n3,3.99\n";
1025 $c->res->content_type('text/comma-separated-values');
1026 $c->res->body($csv);
1029 Normally the browser uses the last part of the URI to generate a
1030 filename for data it cannot display. In this case your browser would
1031 likely ask you to save a file named C<export>.
1033 Luckily you can have the browser download the content with a specific
1034 filename by setting the C<Content-Disposition> header:
1036 my $filename = 'Important Orders.csv';
1037 $c->res->header('Content-Disposition', qq[attachment; filename="$filename"]);
1039 Note the use of quotes around the filename; this ensures that any
1040 spaces in the filename are handled by the browser.
1042 Put this right before calling C<< $c->res->body >> and your browser
1043 will download a file named C<Important Orders.csv> instead of
1046 You can also use this to have the browser download content which it
1047 normally displays, such as JPEG images or even HTML. Just be sure to
1048 set the appropriate content type and disposition.
1053 Controllers are the main point of communication between the web server
1054 and your application. Here we explore some aspects of how they work.
1060 A Catalyst application is driven by one or more Controller
1061 modules. There are a number of ways that Catalyst can decide which of
1062 the methods in your controller modules it should call. Controller
1063 methods are also called actions, because they determine how your
1064 catalyst application should (re-)act to any given URL. When the
1065 application is started up, catalyst looks at all your actions, and
1066 decides which URLs they map to.
1068 =head3 Type attributes
1070 Each action is a normal method in your controller, except that it has an
1071 L<attribute|attributes>
1072 attached. These can be one of several types.
1074 Assume our Controller module starts with the following package declaration:
1076 package MyApp::Controller::Buckets;
1078 and we are running our application on localhost, port 3000 (the test
1085 A Path attribute also takes an argument, this can be either a relative
1086 or an absolute path. A relative path will be relative to the
1087 controller namespace, an absolute path will represent an exact
1090 sub my_handles : Path('handles') { .. }
1094 http://localhost:3000/buckets/handles
1098 sub my_handles : Path('/handles') { .. }
1102 http://localhost:3000/handles
1104 See also: L<Catalyst::DispatchType::Path>
1108 When using a Local attribute, no parameters are needed, instead, the
1109 name of the action is matched in the URL. The namespaces created by
1110 the name of the controller package is always part of the URL.
1112 sub my_handles : Local { .. }
1116 http://localhost:3000/buckets/my_handles
1120 A Global attribute is similar to a Local attribute, except that the
1121 namespace of the controller is ignored, and matching starts at root.
1123 sub my_handles : Global { .. }
1127 http://localhost:3000/my_handles
1131 By now you should have figured that a Regex attribute is just what it
1132 sounds like. This one takes a regular expression, and matches starting
1133 from root. These differ from the rest as they can match multiple URLs.
1135 sub my_handles : Regex('^handles') { .. }
1139 http://localhost:3000/handles
1143 http://localhost:3000/handles_and_other_parts
1147 See also: L<Catalyst::DispatchType::Regex>
1151 A LocalRegex is similar to a Regex, except it only matches below the current
1152 controller namespace.
1154 sub my_handles : LocalRegex(^handles') { .. }
1158 http://localhost:3000/buckets/handles
1162 http://localhost:3000/buckets/handles_and_other_parts
1168 See L<Catalyst::DispatchType::Chained> for a description of how the chained
1169 dispatch type works.
1173 Last but not least, there is the Private attribute, which allows you
1174 to create your own internal actions, which can be forwarded to, but
1175 won't be matched as URLs.
1177 sub my_handles : Private { .. }
1179 becomes nothing at all..
1181 Catalyst also predefines some special Private actions, which you can
1182 override, these are:
1188 The default action will be called, if no other matching action is
1189 found. If you don't have one of these in your namespace, or any sub
1190 part of your namespace, you'll get an error page instead. If you want
1191 to find out where it was the user was trying to go, you can look in
1192 the request object using C<< $c->req->path >>.
1194 sub default :Path { .. }
1196 works for all unknown URLs, in this controller namespace, or every one
1197 if put directly into MyApp.pm.
1201 The index action is called when someone tries to visit the exact
1202 namespace of your controller. If index, default and matching Path
1203 actions are defined, then index will be used instead of default and
1206 sub index :Path :Args(0) { .. }
1210 http://localhost:3000/buckets
1214 The begin action is called at the beginning of every request involving
1215 this namespace directly, before other matching actions are called. It
1216 can be used to set up variables/data for this particular part of your
1217 app. A single begin action is called, its always the one most relevant
1218 to the current namespace.
1220 sub begin : Private { .. }
1224 http://localhost:3000/bucket/(anything)?
1230 Like begin, this action is always called for the namespace it is in,
1231 after every other action has finished. It is commonly used to forward
1232 processing to the View component. A single end action is called, its
1233 always the one most relevant to the current namespace.
1236 sub end : Private { .. }
1238 is called once after any actions when
1240 http://localhost:3000/bucket/(anything)?
1246 Lastly, the auto action is magic in that B<every> auto action in the
1247 chain of paths up to and including the ending namespace, will be
1248 called. (In contrast, only one of the begin/end/default actions will
1249 be called, the relevant one).
1251 package MyApp::Controller::Root;
1252 sub auto : Private { .. }
1256 sub auto : Private { .. }
1258 will both be called when visiting
1260 http://localhost:3000/bucket/(anything)?
1266 =head3 A word of warning
1268 You can put root actions in your main MyApp.pm file, but this is deprecated,
1269 please put your actions into your Root controller.
1273 A graphical flowchart of how the dispatcher works can be found on the wiki at
1274 L<http://dev.catalyst.perl.org/attachment/wiki/WikiStart/catalyst-flow.png>.
1276 =head2 DRY Controllers with Chained actions
1278 Imagine that you would like the following paths in your application:
1282 =item B<< /cd/<ID>/track/<ID> >>
1284 Displays info on a particular track.
1286 In the case of a multi-volume CD, this is the track sequence.
1288 =item B<< /cd/<ID>/volume/<ID>/track/<ID> >>
1290 Displays info on a track on a specific volume.
1294 Here is some example code, showing how to do this with chained controllers:
1296 package CD::Controller;
1297 use base qw/Catalyst::Controller/;
1299 sub root : Chained('/') PathPart('/cd') CaptureArgs(1) {
1300 my ($self, $c, $cd_id) = @_;
1301 $c->stash->{cd_id} = $cd_id;
1302 $c->stash->{cd} = $self->model('CD')->find_by_id($cd_id);
1305 sub trackinfo : Chained('track') PathPart('') Args(0) RenderView {
1306 my ($self, $c) = @_;
1309 package CD::Controller::ByTrackSeq;
1310 use base qw/CD::Controller/;
1312 sub track : Chained('root') PathPart('track') CaptureArgs(1) {
1313 my ($self, $c, $track_seq) = @_;
1314 $c->stash->{track} = $self->stash->{cd}->find_track_by_seq($track_seq);
1317 package CD::Controller::ByTrackVolNo;
1318 use base qw/CD::Controller/;
1320 sub volume : Chained('root') PathPart('volume') CaptureArgs(1) {
1321 my ($self, $c, $volume) = @_;
1322 $c->stash->{volume} = $volume;
1325 sub track : Chained('volume') PathPart('track') CaptureArgs(1) {
1326 my ($self, $c, $track_no) = @_;
1327 $c->stash->{track} = $self->stash->{cd}->find_track_by_vol_and_track_no(
1328 $c->stash->{volume}, $track_no
1332 Note that adding other actions (i.e. chain endpoints) which operate on a track
1333 is simply a matter of adding a new sub to CD::Controller - no code is duplicated,
1334 even though there are two different methods of looking up a track.
1336 This technique can be expanded as needed to fulfil your requirements - for example,
1337 if you inherit the first action of a chain from a base class, then mixing in a
1338 different base class can be used to duplicate an entire URL hierarchy at a different
1339 point within your application.
1341 =head2 Component-based Subrequests
1343 See L<Catalyst::Plugin::SubRequest>.
1347 =head3 Single file upload with Catalyst
1349 To implement uploads in Catalyst, you need to have a HTML form similar to
1352 <form action="/upload" method="post" enctype="multipart/form-data">
1353 <input type="hidden" name="form_submit" value="yes">
1354 <input type="file" name="my_file">
1355 <input type="submit" value="Send">
1358 It's very important not to forget C<enctype="multipart/form-data"> in
1361 Catalyst Controller module 'upload' action:
1363 sub upload : Global {
1364 my ($self, $c) = @_;
1366 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1368 if ( my $upload = $c->request->upload('my_file') ) {
1370 my $filename = $upload->filename;
1371 my $target = "/tmp/upload/$filename";
1373 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1374 die( "Failed to copy '$filename' to '$target': $!" );
1379 $c->stash->{template} = 'file_upload.html';
1382 =head3 Multiple file upload with Catalyst
1384 Code for uploading multiple files from one form needs a few changes:
1386 The form should have this basic structure:
1388 <form action="/upload" method="post" enctype="multipart/form-data">
1389 <input type="hidden" name="form_submit" value="yes">
1390 <input type="file" name="file1" size="50"><br>
1391 <input type="file" name="file2" size="50"><br>
1392 <input type="file" name="file3" size="50"><br>
1393 <input type="submit" value="Send">
1396 And in the controller:
1398 sub upload : Local {
1399 my ($self, $c) = @_;
1401 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1403 for my $field ( $c->req->upload ) {
1405 my $upload = $c->req->upload($field);
1406 my $filename = $upload->filename;
1407 my $target = "/tmp/upload/$filename";
1409 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1410 die( "Failed to copy '$filename' to '$target': $!" );
1415 $c->stash->{template} = 'file_upload.html';
1418 C<for my $field ($c-E<gt>req->upload)> loops automatically over all file
1419 input fields and gets input names. After that is basic file saving code,
1420 just like in single file upload.
1422 Notice: C<die>ing might not be what you want to do, when an error
1423 occurs, but it works as an example. A better idea would be to store
1424 error C<$!> in $c->stash->{error} and show a custom error template
1425 displaying this message.
1427 For more information about uploads and usable methods look at
1428 L<Catalyst::Request::Upload> and L<Catalyst::Request>.
1430 =head2 Forwarding with arguments
1432 Sometimes you want to pass along arguments when forwarding to another
1433 action. As of version 5.30, arguments can be passed in the call to
1434 C<forward>; in earlier versions, you can manually set the arguments in
1435 the Catalyst Request object:
1437 # version 5.30 and later:
1438 $c->forward('/wherever', [qw/arg1 arg2 arg3/]);
1441 $c->req->args([qw/arg1 arg2 arg3/]);
1442 $c->forward('/wherever');
1444 (See the L<Catalyst::Manual::Intro> Flow_Control section for more
1445 information on passing arguments via C<forward>.)
1447 =head2 Chained dispatch using base classes, and inner packages.
1449 package MyApp::Controller::Base;
1450 use base qw/Catalyst::Controller/;
1452 sub key1 : Chained('/')
1454 =head2 Extending RenderView (formerly DefaultEnd)
1456 The recommended approach for an C<end> action is to use
1457 L<Catalyst::Action::RenderView> (taking the place of
1458 L<Catalyst::Plugin::DefaultEnd>), which does what you usually need.
1459 However there are times when you need to add a bit to it, but don't want
1460 to write your own C<end> action.
1462 You can extend it like this:
1464 To add something to an C<end> action that is called before rendering
1465 (this is likely to be what you want), simply place it in the C<end>
1468 sub end : ActionClass('RenderView') {
1469 my ( $self, $c ) = @_;
1470 # do stuff here; the RenderView action is called afterwards
1473 To add things to an C<end> action that are called I<after> rendering,
1474 you can set it up like this:
1476 sub render : ActionClass('RenderView') { }
1479 my ( $self, $c ) = @_;
1480 $c->forward('render');
1488 The recipes below describe aspects of the deployment process,
1489 including web server engines and tips to improve application efficiency.
1491 =head2 mod_perl Deployment
1493 mod_perl is not the best solution for many applications, but we'll list some
1494 pros and cons so you can decide for yourself. The other (recommended)
1495 deployment option is FastCGI, for which see below.
1501 mod_perl is fast and your app will be loaded in memory
1502 within each Apache process.
1504 =head4 Shared memory for multiple apps
1506 If you need to run several Catalyst apps on the same server, mod_perl will
1507 share the memory for common modules.
1513 Since your application is fully loaded in memory, every Apache process will
1514 be rather large. This means a large Apache process will be tied up while
1515 serving static files, large files, or dealing with slow clients. For this
1516 reason, it is best to run a two-tiered web architecture with a lightweight
1517 frontend server passing dynamic requests to a large backend mod_perl
1522 Any changes made to the core code of your app require a full Apache restart.
1523 Catalyst does not support Apache::Reload or StatINC. This is another good
1524 reason to run a frontend web server where you can set up an
1525 C<ErrorDocument 502> page to report that your app is down for maintenance.
1527 =head4 Cannot run multiple versions of the same app
1529 It is not possible to run two different versions of the same application in
1530 the same Apache instance because the namespaces will collide.
1532 =head4 Cannot run different versions of libraries.
1534 If you have two different applications which run on the same machine,
1535 which need two different versions of a library then the only way to do
1536 this is to have per-vhost perl interpreters (with different library paths).
1537 This is entirely possible, but nullifies all the memory sharing benefits that
1538 you get from having multiple applications sharing the same interpreter.
1542 Now that we have that out of the way, let's talk about setting up mod_perl
1543 to run a Catalyst app.
1545 =head4 1. Install Catalyst::Engine::Apache
1547 You should install the latest versions of both Catalyst and
1548 Catalyst::Engine::Apache. The Apache engines were separated from the
1549 Catalyst core in version 5.50 to allow for updates to the engine without
1550 requiring a new Catalyst release.
1552 =head4 2. Install Apache with mod_perl
1554 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
1555 recommended. With Apache 2, make sure you are using the prefork MPM and not
1556 the worker MPM. The reason for this is that many Perl modules are not
1557 thread-safe and may have problems running within the threaded worker
1558 environment. Catalyst is thread-safe however, so if you know what you're
1559 doing, you may be able to run using worker.
1561 In Debian, the following commands should get you going.
1563 apt-get install apache2-mpm-prefork
1564 apt-get install libapache2-mod-perl2
1566 =head4 3. Configure your application
1568 Every Catalyst application will automagically become a mod_perl handler
1569 when run within mod_perl. This makes the configuration extremely easy.
1570 Here is a basic Apache 2 configuration.
1572 PerlSwitches -I/var/www/MyApp/lib
1577 PerlResponseHandler MyApp
1580 The most important line here is C<PerlModule MyApp>. This causes mod_perl
1581 to preload your entire application into shared memory, including all of your
1582 controller, model, and view classes and configuration. If you have -Debug
1583 mode enabled, you will see the startup output scroll by when you first
1586 For an example Apache 1.3 configuration, please see the documentation for
1587 L<Catalyst::Engine::Apache::MP13>.
1591 That's it, your app is now a full-fledged mod_perl application! Try it out
1592 by going to http://your.server.com/.
1594 =head3 Other Options
1596 =head4 Non-root location
1598 You may not always want to run your app at the root of your server or virtual
1599 host. In this case, it's a simple change to run at any non-root location
1604 PerlResponseHandler MyApp
1607 When running this way, it is best to make use of the C<uri_for> method in
1608 Catalyst for constructing correct links.
1610 =head4 Static file handling
1612 Static files can be served directly by Apache for a performance boost.
1614 DocumentRoot /var/www/MyApp/root
1616 SetHandler default-handler
1619 This will let all files within root/static be handled directly by Apache. In
1620 a two-tiered setup, the frontend server should handle static files.
1621 The configuration to do this on the frontend will vary.
1623 The same is accomplished in lighttpd with the following snippet:
1625 $HTTP["url"] !~ "^/(?:img/|static/|css/|favicon.ico$)" {
1629 "socket" => "/tmp/myapp.socket",
1630 "check-local" => "disable",
1636 Which serves everything in the img, static, css directories
1637 statically, as well as the favicon file.
1639 Note the path of the application needs to be stated explicitly in the
1640 web server configuration for both these recipes.
1642 =head2 Catalyst on shared hosting
1644 So, you want to put your Catalyst app out there for the whole world to
1645 see, but you don't want to break the bank. There is an answer - if you
1646 can get shared hosting with FastCGI and a shell, you can install your
1647 Catalyst app in a local directory on your shared host. First, run
1649 perl -MCPAN -e shell
1651 and go through the standard CPAN configuration process. Then exit out
1652 without installing anything. Next, open your .bashrc and add
1654 export PATH=$HOME/local/bin:$HOME/local/script:$PATH
1655 perlversion=`perl -v | grep 'built for' | awk '{print $4}' | sed -e 's/v//;'`
1656 export PERL5LIB=$HOME/local/share/perl/$perlversion:$HOME/local/lib/perl/$perlversion:$HOME/local/lib:$PERL5LIB
1658 and log out, then back in again (or run C<". .bashrc"> if you
1659 prefer). Finally, edit C<.cpan/CPAN/MyConfig.pm> and add
1661 'make_install_arg' => qq[SITEPREFIX=$ENV{HOME}/local],
1662 'makepl_arg' => qq[INSTALLDIRS=site install_base=$ENV{HOME}/local],
1664 Now you can install the modules you need using CPAN as normal; they
1665 will be installed into your local directory, and perl will pick them
1666 up. Finally, change directory into the root of your virtual host and
1667 symlink your application's script directory in:
1669 cd path/to/mydomain.com
1670 ln -s ~/lib/MyApp/script script
1672 And add the following lines to your .htaccess file (assuming the server
1673 is setup to handle .pl as fcgi - you may need to rename the script to
1674 myapp_fastcgi.fcgi and/or use a SetHandler directive):
1677 RewriteCond %{REQUEST_URI} !^/?script/myapp_fastcgi.pl
1678 RewriteRule ^(.*)$ script/myapp_fastcgi.pl/$1 [PT,L]
1680 Now C<http://mydomain.com/> should now Just Work. Congratulations, now
1681 you can tell your friends about your new website (or in our case, tell
1682 the client it's time to pay the invoice :) )
1684 =head2 FastCGI Deployment
1686 FastCGI is a high-performance extension to CGI. It is suitable
1687 for production environments.
1693 FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you;
1694 your app runs as multiple persistent processes ready to receive connections
1695 from the web server.
1699 When using external FastCGI servers, your application runs as a standalone
1700 application server. It may be restarted independently from the web server.
1701 This allows for a more robust environment and faster reload times when
1702 pushing new app changes. The frontend server can even be configured to
1703 display a friendly "down for maintenance" page while the application is
1706 =head4 Load-balancing
1708 You can launch your application on multiple backend servers and allow the
1709 frontend web server to load-balance between all of them. And of course, if
1710 one goes down, your app continues to run fine.
1712 =head4 Multiple versions of the same app
1714 Each FastCGI application is a separate process, so you can run different
1715 versions of the same app on a single server.
1717 =head4 Can run with threaded Apache
1719 Since your app is not running inside of Apache, the faster mpm_worker module
1720 can be used without worrying about the thread safety of your application.
1724 You may have to disable mod_deflate. If you experience page hangs with
1725 mod_fastcgi then remove deflate.load and deflate.conf from mods-enabled/
1727 =head4 More complex environment
1729 With FastCGI, there are more things to monitor and more processes running
1730 than when using mod_perl.
1734 =head4 1. Install Apache with mod_fastcgi
1736 mod_fastcgi for Apache is a third party module, and can be found at
1737 L<http://www.fastcgi.com/>. It is also packaged in many distributions,
1738 for example, libapache2-mod-fastcgi in Debian. You will also need to install
1739 the L<FCGI> module from cpan.
1741 Important Note! If you experience difficulty properly rendering pages,
1742 try disabling Apache's mod_deflate (Deflate Module), e.g. 'a2dismod deflate'.
1744 =head4 2. Configure your application
1746 # Serve static content directly
1747 DocumentRoot /var/www/MyApp/root
1748 Alias /static /var/www/MyApp/root/static
1750 FastCgiServer /var/www/MyApp/script/myapp_fastcgi.pl -processes 3
1751 Alias /myapp/ /var/www/MyApp/script/myapp_fastcgi.pl/
1753 # Or, run at the root
1754 Alias / /var/www/MyApp/script/myapp_fastcgi.pl/
1756 The above commands will launch 3 app processes and make the app available at
1759 =head3 Standalone server mode
1761 While not as easy as the previous method, running your app as an external
1762 server gives you much more flexibility.
1764 First, launch your app as a standalone server listening on a socket.
1766 script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5 -p /tmp/myapp.pid -d
1768 You can also listen on a TCP port if your web server is not on the same
1771 script/myapp_fastcgi.pl -l :8080 -n 5 -p /tmp/myapp.pid -d
1773 You will probably want to write an init script to handle starting/stopping
1774 of the app using the pid file.
1776 Now, we simply configure Apache to connect to the running server.
1778 # 502 is a Bad Gateway error, and will occur if the backend server is down
1779 # This allows us to display a friendly static page that says "down for
1781 Alias /_errors /var/www/MyApp/root/error-pages
1782 ErrorDocument 502 /_errors/502.html
1784 FastCgiExternalServer /tmp/myapp.fcgi -socket /tmp/myapp.socket
1785 Alias /myapp/ /tmp/myapp.fcgi/
1787 # Or, run at the root
1788 Alias / /tmp/myapp.fcgi/
1792 L<Catalyst::Engine::FastCGI>.
1794 =head2 Development server deployment
1796 The development server is a mini web server written in perl. If you
1797 expect a low number of hits or you don't need mod_perl/FastCGI speed,
1798 you could use the development server as the application server with a
1799 lightweight proxy web server at the front. However, consider using
1800 L<Catalyst::Engine::HTTP::Prefork> for this kind of deployment instead, since
1801 it can better handle multiple concurrent requests without forking, or can
1802 prefork a set number of servers for improved performance.
1806 As this is an application server setup, the pros are the same as
1807 FastCGI (with the exception of speed).
1812 The development server is what you create your code on, so if it works
1813 here, it should work in production!
1819 Not as fast as mod_perl or FastCGI. Needs to fork for each request
1820 that comes in - make sure static files are served by the web server to
1825 =head4 Start up the development server
1827 script/myapp_server.pl -p 8080 -k -f -pidfile=/tmp/myapp.pid
1829 You will probably want to write an init script to handle stop/starting
1830 the app using the pid file.
1832 =head4 Configuring Apache
1834 Make sure mod_proxy is enabled and add:
1836 # Serve static content directly
1837 DocumentRoot /var/www/MyApp/root
1838 Alias /static /var/www/MyApp/root/static
1846 # Need to specifically stop these paths from being passed to proxy
1848 ProxyPass /favicon.ico !
1850 ProxyPass / http://localhost:8080/
1851 ProxyPassReverse / http://localhost:8080/
1853 # This is optional if you'd like to show a custom error page
1854 # if the proxy is not available
1855 ErrorDocument 502 /static/error_pages/http502.html
1857 You can wrap the above within a VirtualHost container if you want
1858 different apps served on the same host.
1860 =head2 Quick deployment: Building PAR Packages
1862 You have an application running on your development box, but then you
1863 have to quickly move it to another one for
1864 demonstration/deployment/testing...
1866 PAR packages can save you from a lot of trouble here. They are usual Zip
1867 files that contain a blib tree; you can even include all prereqs and a
1868 perl interpreter by setting a few flags!
1870 =head3 Follow these few points to try it out!
1872 1. Install Catalyst and PAR 0.89 (or later)
1874 % perl -MCPAN -e 'install Catalyst'
1876 % perl -MCPAN -e 'install PAR'
1879 2. Create a application
1885 Recent versions of Catalyst (5.62 and up) include
1886 L<Module::Install::Catalyst>, which simplifies the process greatly. From the shell in your application directory:
1891 You can customise the PAR creation process by special "catalyst_par_*" commands
1892 available from L<Module::Install::Catalyst>. You can add these commands in your
1893 Makefile.PL just before the line containing "catalyst;"
1895 #Makefile.PL example with extra PAR options
1896 use inc::Module::Install;
1899 all_from 'lib\MyApp.pm';
1901 requires 'Catalyst::Runtime' => '5.80005';
1906 catalyst_par_core(1); # bundle perl core modules in the resulting PAR
1907 catalyst_par_multiarch(1); # build a multi-architecture PAR file
1908 catalyst_par_classes(qw/
1909 Some::Additional::Module
1911 /); # specify additional modules you want to be included into PAR
1914 install_script glob('script/*.pl');
1918 Congratulations! Your package "myapp.par" is ready, the following
1919 steps are just optional.
1921 3. Test your PAR package with "parl" (no typo)
1925 [parl] myapp[.par] [script] [arguments]
1928 parl myapp.par myapp_server.pl -r
1938 % parl myapp.par myapp_server.pl
1939 You can connect to your server at http://localhost:3000
1941 Yes, this nifty little starter application gets automatically included.
1942 You can also use "catalyst_par_script('myapp_server.pl')" to set a
1943 default script to execute.
1945 6. Want to create a binary that includes the Perl interpreter?
1947 % pp -o myapp myapp.par
1948 % ./myapp myapp_server.pl
1949 You can connect to your server at http://localhost:3000
1951 =head2 Serving static content
1953 Serving static content in Catalyst used to be somewhat tricky; the use
1954 of L<Catalyst::Plugin::Static::Simple> makes everything much easier.
1955 This plugin will automatically serve your static content during development,
1956 but allows you to easily switch to Apache (or other server) in a
1957 production environment.
1959 =head3 Introduction to Static::Simple
1961 Static::Simple is a plugin that will help to serve static content for your
1962 application. By default, it will serve most types of files, excluding some
1963 standard Template Toolkit extensions, out of your B<root> file directory. All
1964 files are served by path, so if B<images/me.jpg> is requested, then
1965 B<root/images/me.jpg> is found and served.
1969 Using the plugin is as simple as setting your use line in MyApp.pm to include:
1971 use Catalyst qw/Static::Simple/;
1973 and already files will be served.
1977 Static content is best served from a single directory within your root
1978 directory. Having many different directories such as C<root/css> and
1979 C<root/images> requires more code to manage, because you must separately
1980 identify each static directory--if you decide to add a C<root/js>
1981 directory, you'll need to change your code to account for it. In
1982 contrast, keeping all static directories as subdirectories of a main
1983 C<root/static> directory makes things much easier to manage. Here's an
1984 example of a typical root directory structure:
1988 root/controller/stuff.tt
1991 root/static/css/main.css
1992 root/static/images/logo.jpg
1993 root/static/js/code.js
1996 All static content lives under C<root/static>, with everything else being
1997 Template Toolkit files.
2003 You may of course want to change the default locations, and make
2004 Static::Simple look somewhere else, this is as easy as:
2006 MyApp->config->{static}->{include_path} = [
2007 MyApp->config->{root},
2011 When you override include_path, it will not automatically append the
2012 normal root path, so you need to add it yourself if you still want
2013 it. These will be searched in order given, and the first matching file
2016 =item Static directories
2018 If you want to force some directories to be only static, you can set
2019 them using paths relative to the root dir, or regular expressions:
2021 MyApp->config->{static}->{dirs} = [
2026 =item File extensions
2028 By default, the following extensions are not served (that is, they will
2029 be processed by Catalyst): B<tmpl, tt, tt2, html, xhtml>. This list can
2032 MyApp->config->{static}->{ignore_extensions} = [
2033 qw/tmpl tt tt2 html xhtml/
2036 =item Ignoring directories
2038 Entire directories can be ignored. If used with include_path,
2039 directories relative to the include_path dirs will also be ignored:
2041 MyApp->config->{static}->{ignore_dirs} = [ qw/tmpl css/ ];
2045 =head3 More information
2047 L<http://search.cpan.org/dist/Catalyst-Plugin-Static-Simple/>
2049 =head3 Serving manually with the Static plugin with HTTP::Daemon (myapp_server.pl)
2051 In some situations you might want to control things more directly,
2052 using L<Catalyst::Plugin::Static>.
2054 In your main application class (MyApp.pm), load the plugin:
2056 use Catalyst qw/-Debug FormValidator Static OtherPlugin/;
2058 You will also need to make sure your end method does I<not> forward
2059 static content to the view, perhaps like this:
2062 my ( $self, $c ) = @_;
2064 $c->forward( 'MyApp::View::TT' )
2065 unless ( $c->res->body || !$c->stash->{template} );
2068 This code will only forward to the view if a template has been
2069 previously defined by a controller and if there is not already data in
2070 C<$c-E<gt>res-E<gt>body>.
2072 Next, create a controller to handle requests for the /static path. Use
2073 the Helper to save time. This command will create a stub controller as
2074 C<lib/MyApp/Controller/Static.pm>.
2076 $ script/myapp_create.pl controller Static
2078 Edit the file and add the following methods:
2080 # serve all files under /static as static files
2081 sub default : Path('/static') {
2082 my ( $self, $c ) = @_;
2084 # Optional, allow the browser to cache the content
2085 $c->res->headers->header( 'Cache-Control' => 'max-age=86400' );
2087 $c->serve_static; # from Catalyst::Plugin::Static
2090 # also handle requests for /favicon.ico
2091 sub favicon : Path('/favicon.ico') {
2092 my ( $self, $c ) = @_;
2097 You can also define a different icon for the browser to use instead of
2098 favicon.ico by using this in your HTML header:
2100 <link rel="icon" href="/static/myapp.ico" type="image/x-icon" />
2102 =head3 Common problems with the Static plugin
2104 The Static plugin makes use of the C<shared-mime-info> package to
2105 automatically determine MIME types. This package is notoriously
2106 difficult to install, especially on win32 and OS X. For OS X the easiest
2107 path might be to install Fink, then use C<apt-get install
2108 shared-mime-info>. Restart the server, and everything should be fine.
2110 Make sure you are using the latest version (>= 0.16) for best
2111 results. If you are having errors serving CSS files, or if they get
2112 served as text/plain instead of text/css, you may have an outdated
2113 shared-mime-info version. You may also wish to simply use the following
2114 code in your Static controller:
2116 if ($c->req->path =~ /css$/i) {
2117 $c->serve_static( "text/css" );
2122 =head3 Serving Static Files with Apache
2124 When using Apache, you can bypass Catalyst and any Static
2125 plugins/controllers controller by intercepting requests for the
2126 C<root/static> path at the server level. All that is required is to
2127 define a DocumentRoot and add a separate Location block for your static
2128 content. Here is a complete config for this application under mod_perl
2132 use lib qw(/var/www/MyApp/lib);
2137 ServerName myapp.example.com
2138 DocumentRoot /var/www/MyApp/root
2140 SetHandler perl-script
2143 <LocationMatch "/(static|favicon.ico)">
2144 SetHandler default-handler
2148 And here's a simpler example that'll get you started:
2150 Alias /static/ "/my/static/files/"
2151 <Location "/static">
2157 Catalyst makes it easy to employ several different types of caching to
2158 speed up your applications.
2160 =head3 Cache Plugins
2162 There are three wrapper plugins around common CPAN cache modules:
2163 Cache::FastMmap, Cache::FileCache, and Cache::Memcached. These can be
2164 used to cache the result of slow operations.
2166 The Catalyst Advent Calendar uses the FileCache plugin to cache the
2167 rendered XHTML version of the source POD document. This is an ideal
2168 application for a cache because the source document changes
2169 infrequently but may be viewed many times.
2171 use Catalyst qw/Cache::FileCache/;
2176 sub render_pod : Local {
2177 my ( self, $c ) = @_;
2179 # the cache is keyed on the filename and the modification time
2180 # to check for updates to the file.
2181 my $file = $c->path_to( 'root', '2005', '11.pod' );
2182 my $mtime = ( stat $file )->mtime;
2184 my $cached_pod = $c->cache->get("$file $mtime");
2185 if ( !$cached_pod ) {
2186 $cached_pod = do_slow_pod_rendering();
2187 # cache the result for 12 hours
2188 $c->cache->set( "$file $mtime", $cached_pod, '12h' );
2190 $c->stash->{pod} = $cached_pod;
2193 We could actually cache the result forever, but using a value such as 12 hours
2194 allows old entries to be automatically expired when they are no longer needed.
2198 Another method of caching is to cache the entire HTML page. While this is
2199 traditionally handled by a front-end proxy server like Squid, the Catalyst
2200 PageCache plugin makes it trivial to cache the entire output from
2201 frequently-used or slow actions.
2203 Many sites have a busy content-filled front page that might look something
2204 like this. It probably takes a while to process, and will do the exact same
2205 thing for every single user who views the page.
2207 sub front_page : Path('/') {
2208 my ( $self, $c ) = @_;
2210 $c->forward( 'get_news_articles' );
2211 $c->forward( 'build_lots_of_boxes' );
2212 $c->forward( 'more_slow_stuff' );
2214 $c->stash->{template} = 'index.tt';
2217 We can add the PageCache plugin to speed things up.
2219 use Catalyst qw/Cache::FileCache PageCache/;
2221 sub front_page : Path ('/') {
2222 my ( $self, $c ) = @_;
2224 $c->cache_page( 300 );
2226 # same processing as above
2229 Now the entire output of the front page, from <html> to </html>, will be
2230 cached for 5 minutes. After 5 minutes, the next request will rebuild the
2231 page and it will be re-cached.
2233 Note that the page cache is keyed on the page URI plus all parameters, so
2234 requests for / and /?foo=bar will result in different cache items. Also,
2235 only GET requests will be cached by the plugin.
2237 You can even get that front-end Squid proxy to help out by enabling HTTP
2238 headers for the cached page.
2240 MyApp->config->{page_cache}->{set_http_headers} = 1;
2242 This would now set the following headers so proxies and browsers may cache
2243 the content themselves.
2245 Cache-Control: max-age=($expire_time - time)
2246 Expires: $expire_time
2247 Last-Modified: $cache_created_time
2249 =head3 Template Caching
2251 Template Toolkit provides support for caching compiled versions of your
2252 templates. To enable this in Catalyst, use the following configuration.
2253 TT will cache compiled templates keyed on the file mtime, so changes will
2254 still be automatically detected.
2256 package MyApp::View::TT;
2260 use base 'Catalyst::View::TT';
2262 __PACKAGE__->config(
2263 COMPILE_DIR => '/tmp/template_cache',
2270 See the documentation for each cache plugin for more details and other
2271 available configuration options.
2273 L<Catalyst::Plugin::Cache::FastMmap>
2274 L<Catalyst::Plugin::Cache::FileCache>
2275 L<Catalyst::Plugin::Cache::Memcached>
2276 L<Catalyst::Plugin::PageCache>
2277 L<http://search.cpan.org/dist/Template-Toolkit/lib/Template/Manual/Config.pod#Caching_and_Compiling_Options>
2281 Testing is an integral part of the web application development
2282 process. Tests make multi developer teams easier to coordinate, and
2283 they help ensure that there are no nasty surprises after upgrades or
2288 Catalyst provides a convenient way of testing your application during
2289 development and before deployment in a real environment.
2291 C<Catalyst::Test> makes it possible to run the same tests both locally
2292 (without an external daemon) and against a remote server via HTTP.
2296 Let's examine a skeleton application's C<t/> directory:
2298 mundus:~/MyApp chansen$ ls -l t/
2300 -rw-r--r-- 1 chansen chansen 95 18 Dec 20:50 01app.t
2301 -rw-r--r-- 1 chansen chansen 190 18 Dec 20:50 02pod.t
2302 -rw-r--r-- 1 chansen chansen 213 18 Dec 20:50 03podcoverage.t
2308 Verifies that the application loads, compiles, and returns a successful
2313 Verifies that all POD is free from errors. Only executed if the C<TEST_POD>
2314 environment variable is true.
2316 =item C<03podcoverage.t>
2318 Verifies that all methods/functions have POD coverage. Only executed if the
2319 C<TEST_POD> environment variable is true.
2323 =head3 Creating tests
2325 mundus:~/MyApp chansen$ cat t/01app.t | perl -ne 'printf( "%2d %s", $., $_ )'
2326 1 use Test::More tests => 2;
2327 2 BEGIN { use_ok( Catalyst::Test, 'MyApp' ) }
2329 4 ok( request('/')->is_success );
2331 The first line declares how many tests we are going to run, in this case
2332 two. The second line tests and loads our application in test mode. The
2333 fourth line verifies that our application returns a successful response.
2335 C<Catalyst::Test> exports two functions, C<request> and C<get>. Each can
2336 take three different arguments:
2340 =item A string which is a relative or absolute URI.
2342 request('/my/path');
2343 request('http://www.host.com/my/path');
2345 =item An instance of C<URI>.
2347 request( URI->new('http://www.host.com/my/path') );
2349 =item An instance of C<HTTP::Request>.
2351 request( HTTP::Request->new( GET => 'http://www.host.com/my/path') );
2355 C<request> returns an instance of C<HTTP::Response> and C<get> returns the
2356 content (body) of the response.
2358 =head3 Running tests locally
2360 mundus:~/MyApp chansen$ CATALYST_DEBUG=0 TEST_POD=1 prove --lib lib/ t/
2361 t/01app............ok
2362 t/02pod............ok
2363 t/03podcoverage....ok
2364 All tests successful.
2365 Files=3, Tests=4, 2 wallclock secs ( 1.60 cusr + 0.36 csys = 1.96 CPU)
2367 C<CATALYST_DEBUG=0> ensures that debugging is off; if it's enabled you
2368 will see debug logs between tests.
2370 C<TEST_POD=1> enables POD checking and coverage.
2372 C<prove> A command-line tool that makes it easy to run tests. You can
2373 find out more about it from the links below.
2375 =head3 Running tests remotely
2377 mundus:~/MyApp chansen$ CATALYST_SERVER=http://localhost:3000/ prove --lib lib/ t/01app.t
2379 All tests successful.
2380 Files=1, Tests=2, 0 wallclock secs ( 0.40 cusr + 0.01 csys = 0.41 CPU)
2382 C<CATALYST_SERVER=http://localhost:3000/> is the absolute deployment URI of
2383 your application. In C<CGI> or C<FastCGI> it should be the host and path
2386 =head3 C<Test::WWW::Mechanize> and Catalyst
2388 Be sure to check out C<Test::WWW::Mechanize::Catalyst>. It makes it easy to
2389 test HTML, forms and links. A short example of usage:
2391 use Test::More tests => 6;
2392 BEGIN { use_ok( Test::WWW::Mechanize::Catalyst, 'MyApp' ) }
2394 my $mech = Test::WWW::Mechanize::Catalyst->new;
2395 $mech->get_ok("http://localhost/", 'Got index page');
2396 $mech->title_like( qr/^MyApp on Catalyst/, 'Got right index title' );
2397 ok( $mech->find_link( text_regex => qr/^Wiki/i ), 'Found link to Wiki' );
2398 ok( $mech->find_link( text_regex => qr/^Mailing-List/i ), 'Found link to Mailing-List' );
2399 ok( $mech->find_link( text_regex => qr/^IRC channel/i ), 'Found link to IRC channel' );
2401 =head3 Further Reading
2405 =item Catalyst::Test
2409 =item Test::WWW::Mechanize::Catalyst
2411 L<http://search.cpan.org/dist/Test-WWW-Mechanize-Catalyst/lib/Test/WWW/Mechanize/Catalyst.pm>
2413 =item Test::WWW::Mechanize
2415 L<http://search.cpan.org/dist/Test-WWW-Mechanize/Mechanize.pm>
2417 =item WWW::Mechanize
2419 L<http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm>
2421 =item LWP::UserAgent
2423 L<http://search.cpan.org/dist/libwww-perl/lib/LWP/UserAgent.pm>
2427 L<http://search.cpan.org/dist/libwww-perl/lib/HTML/Form.pm>
2431 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Message.pm>
2435 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request.pm>
2437 =item HTTP::Request::Common
2439 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request/Common.pm>
2441 =item HTTP::Response
2443 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Response.pm>
2447 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Status.pm>
2451 L<http://search.cpan.org/dist/URI/URI.pm>
2455 L<http://search.cpan.org/dist/Test-Simple/lib/Test/More.pm>
2459 L<http://search.cpan.org/dist/Test-Pod/Pod.pm>
2461 =item Test::Pod::Coverage
2463 L<http://search.cpan.org/dist/Test-Pod-Coverage/Coverage.pm>
2465 =item prove (Test::Harness)
2467 L<http://search.cpan.org/dist/Test-Harness/bin/prove>
2471 =head3 More Information
2473 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::Roles>
2474 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::ACL>
2478 Catalyst Contributors, see Catalyst.pm
2482 This library is free software. You can redistribute it and/or modify it under
2483 the same terms as Perl itself.