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 $c->stash->{template} = 'errors.tt';
37 $c->forward('MyApp::View::TT');
41 return 1 if $c->response->status =~ /^3\d\d$/;
42 return 1 if $c->response->body;
44 unless ( $c->response->content_type ) {
45 $c->response->content_type('text/html; charset=utf-8');
48 $c->forward('MyApp::View::TT');
51 You can manually set errors in your code to trigger this page by calling
53 $c->error( 'You broke me!' );
55 =head2 Disable statistics
57 Just add this line to your application class if you don't want those
58 nifty statistics in your debug messages.
60 sub Catalyst::Log::info { }
62 =head2 Enable debug status in the environment
64 Normally you enable the debugging info by adding the C<-Debug> flag to
65 your C<use Catalyst> statement . However, you can also enable it using
66 environment variable, so you can (for example) get debug info without
67 modifying your application scripts. Just set C<CATALYST_DEBUG> or
68 C<E<lt>MYAPPE<gt>_DEBUG> to a true value.
72 When you have your users identified, you will want to somehow remember
73 that fact, to save them from having to identify themselves for every
74 single page. One way to do this is to send the username and password
75 parameters in every single page, but that's ugly, and won't work for
78 Sessions are a method of saving data related to some transaction, and
79 giving the whole collection a single ID. This ID is then given to the
80 user to return to us on every page they visit while logged in. The
81 usual way to do this is using a browser cookie.
83 Catalyst uses two types of plugins to represent sessions:
87 A State module is used to keep track of the state of the session
88 between the users browser, and your application.
90 A common example is the Cookie state module, which sends the browser a
91 cookie containing the session ID. It will use default value for the
92 cookie name and domain, so will "just work" when used.
96 A Store module is used to hold all the data relating to your session,
97 for example the users ID, or the items for their shopping cart. You
98 can store data in memory (FastMmap), in a file (File) or in a database
101 =head3 Authentication magic
103 If you have included the session modules in your application, the
104 Authentication modules will automagically use your session to save and
105 retrieve the user data for you.
107 =head3 Using a session
109 Once the session modules are loaded, the session is available as C<<
110 $c->session >>, and can be writen to and read from as a simple hash
117 use namespace::autoclean;
121 Session::Store::FastMmap
122 Session::State::Cookie
127 package MyApp::Controller::Foo;
129 use namespace::autoclean;
130 BEGIN { extends 'Catalyst::Controller' };
131 ## Write data into the session
133 sub add_item : Local {
134 my ( $self, $c ) = @_;
136 my $item_id = $c->req->params->{item};
138 push @{ $c->session->{items} }, $item_id;
142 ## A page later we retrieve the data from the session:
144 sub get_items : Local {
145 my ( $self, $c ) = @_;
147 $c->stash->{items_to_display} = $c->session->{items};
152 =head3 More information
154 L<http://search.cpan.org/dist/Catalyst-Plugin-Session>
156 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-Cookie>
158 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-URI>
160 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-FastMmap>
162 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-File>
164 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-DBI>
166 =head2 Configure your application
168 You configure your application with the C<config> method in your
169 application class. This can be hard-coded, or brought in from a
170 separate configuration file.
172 =head3 Using Config::General
174 L<Config::General|Config::General> is a method for creating flexible
175 and readable configuration files. It's a great way to keep your
176 Catalyst application configuration in one easy-to-understand location.
178 Now create C<myapp.conf> in your application home:
182 # session; perldoc Catalyst::Plugin::Session::FastMmap
186 storage /tmp/myapp.session
189 # emails; perldoc Catalyst::Plugin::Email
190 # this passes options as an array :(
194 This is equivalent to:
196 # configure base package
197 __PACKAGE__->config( name => MyApp );
198 # configure authentication
199 __PACKAGE__->config->{authentication} = {
200 user_class => 'MyApp::Model::MyDB::Customer',
204 __PACKAGE__->config->{session} = {
208 # configure email sending
209 __PACKAGE__->config->{email} = [qw/SMTP localhost/];
211 See also L<Config::General|Config::General>.
213 =head1 Skipping your VCS's directories
215 Catalyst uses Module::Pluggable to load Models, Views, and Controllers.
216 Module::Pluggable will scan through all directories and load modules
217 it finds. Sometimes you might want to skip some of these directories,
218 for example when your version control system makes a subdirectory with
219 meta-information in every version-controlled directory. While
220 Catalyst skips subversion and CVS directories already, there are other
221 source control systems. Here is the configuration you need to add
222 their directories to the list to skip.
224 You can make Catalyst skip these directories using the Catalyst config:
226 # Configure the application
229 setup_components => { except => qr/SCCS/ },
232 See the Module::Pluggable manual page for more information on B<except>
235 =head1 Users and Access Control
237 Most multiuser, and some single-user web applications require that
238 users identify themselves, and the application is often required to
239 define those roles. The recipes below describe some ways of doing
242 =head2 Authentication (logging in)
244 This is extensively covered in other documentation; see in particular
245 L<Catalyst::Plugin::Authentication> and the Authentication chapter
246 of the Tutorial at L<Catalyst::Manual::Tutorial::06_Authorization>.
248 =head2 Pass-through login (and other actions)
250 An easy way of having assorted actions that occur during the processing
251 of a request that are orthogonal to its actual purpose - logins, silent
252 commands etc. Provide actions for these, but when they're required for
253 something else fill e.g. a form variable __login and have a sub begin
256 sub begin : Private {
258 foreach my $action (qw/login docommand foo bar whatever/) {
259 if ($c->req->params->{"__${action}"}) {
260 $c->forward($action);
265 =head2 Authentication/Authorization
267 This is done in several steps:
273 Getting the user to identify themselves, by giving you some piece of
274 information known only to you and the user. Then you can assume that
275 the user is who they say they are. This is called B<credential
280 Making sure the user only accesses functions you want them to
281 access. This is done by checking the verified user's data against your
282 internal list of groups, or allowed persons for the current page.
288 The Catalyst Authentication system is made up of many interacting
289 modules, to give you the most flexibility possible.
291 =head4 Credential verifiers
293 A Credential module tables the user input, and passes it to a Store,
294 or some other system, for verification. Typically, a user object is
295 created by either this module or the Store and made accessible by a
296 C<< $c->user >> call.
300 Password - Simple username/password checking.
301 HTTPD - Checks using basic HTTP auth.
302 TypeKey - Check using the typekey system.
304 =head3 Storage backends
306 A Storage backend contains the actual data representing the users. It
307 is queried by the credential verifiers. Updating the store is not done
308 within this system; you will need to do it yourself.
312 DBIC - Storage using a database via DBIx::Class.
313 Minimal - Storage using a simple hash (for testing).
317 A User object is created by either the storage backend or the
318 credential verifier, and is filled with the retrieved user information.
322 Hash - A simple hash of keys and values.
324 =head3 ACL authorization
326 ACL stands for Access Control List. The ACL plugin allows you to
327 regulate access on a path-by-path basis, by listing which users, or
328 roles, have access to which paths.
330 =head3 Roles authorization
332 Authorization by roles is for assigning users to groups, which can
333 then be assigned to ACLs, or just checked when needed.
337 When you have chosen your modules, all you need to do is call the C<<
338 $c->authenticate >> method. If called with no parameters, it will try to find
339 suitable parameters, such as B<username> and B<password>, or you can
340 pass it these values.
342 =head3 Checking roles
344 Role checking is done by using the C<< $c->check_user_roles >> method.
345 This will check using the currently logged-in user (via C<< $c->user
346 >>). You pass it the name of a role to check, and it returns true if
347 the user is a member.
353 use namespace::autoclean;
354 extends qw/Catalyst/;
362 default_realm => 'test',
367 password_field => 'password',
368 password_type => 'self_check',
379 package MyApp::Controller::Root;
381 use namespace::autoclean;
383 BEGIN { extends 'Catalyst::Controller' }
385 __PACKAGE__->config(namespace => '');
390 if ( my $user = $c->req->params->{user}
391 and my $password = $c->req->param->{password} )
393 if ( $c->authenticate( username => $user, password => $password ) ) {
394 $c->res->body( "hello " . $c->user->name );
404 sub restricted : Local {
405 my ( $self, $c ) = @_;
407 $c->detach("unauthorized")
408 unless $c->check_user_roles( "admin" );
410 # do something restricted here
413 =head3 Using authentication in a testing environment
415 Ideally, to write tests for authentication/authorization code one would
416 first set up a test database with known data, then use
417 L<Test::WWW::Mechanize::Catalyst> to simulate a user logging
418 in. Unfortunately this can be rather awkward, which is why it's a good
419 thing that the authentication framework is so flexible.
421 Instead of using a test database, one can simply change the
422 authentication store to something a bit easier to deal with in a
423 testing environment. Additionally, this has the advantage of not
424 modifying one's database, which can be problematic if one forgets to
425 use the testing instead of production database.
427 Alternatively, if you want to authenticate real users, but not have to
428 worry about their passwords, you can use
429 L<Catalyst::Authentication::Credential::Testing> to force all users to
430 authenticate with a global password.
432 =head3 More information
434 L<Catalyst::Plugin::Authentication> has a longer explanation.
440 Authorization is the step that comes after
441 authentication. Authentication establishes that the user agent is really
442 representing the user we think it's representing, and then authorization
443 determines what this user is allowed to do.
445 =head3 Role Based Access Control
447 Under role based access control each user is allowed to perform any
448 number of roles. For example, at a zoo no one but specially trained
449 personnel can enter the moose cage (Mynd you, møøse bites kan be
450 pretty nasti!). For example:
452 package Zoo::Controller::MooseCage;
454 sub feed_moose : Local {
455 my ( $self, $c ) = @_;
457 $c->model( "Moose" )->eat( $c->req->params->{food} );
460 With this action, anyone can just come into the moose cage and feed
461 the moose, which is a very dangerous thing. We need to restrict this
462 action, so that only a qualified moose feeder can perform that action.
464 The Authorization::Roles plugin lets us perform role based access
465 control checks. Let's load it:
467 use parent qw/Catalyst/;
473 And now our action should look like this:
475 sub feed_moose : Local {
476 my ( $self, $c ) = @_;
478 if ( $c->check_roles( "moose_feeder" ) ) {
479 $c->model( "Moose" )->eat( $c->req->params->{food} );
481 $c->stash->{error} = "unauthorized";
485 This checks C<< $c->user >>, and only if the user has B<all> the roles
486 in the list, a true value is returned.
488 C<check_roles> has a sister method, C<assert_roles>, which throws an
489 exception if any roles are missing.
491 Some roles that might actually make sense in, say, a forum application:
505 each with a distinct task (system administration versus content
508 =head3 Access Control Lists
510 Checking for roles all the time can be tedious and error prone.
512 The Authorization::ACL plugin lets us declare where we'd like checks
513 to be done automatically for us.
515 For example, we may want to completely block out anyone who isn't a
516 C<moose_feeder> from the entire C<MooseCage> controller:
518 Zoo->deny_access_unless( "/moose_cage", [qw/moose_feeder/] );
520 The role list behaves in the same way as C<check_roles>. However, the
521 ACL plugin isn't limited to just interacting with the Roles plugin. We
522 can use a code reference instead. For example, to allow either moose
523 trainers or moose feeders into the moose cage, we can create a more
526 Zoo->deny_access_unless( "/moose_cage", sub {
528 $c->check_roles( "moose_trainer" ) || $c->check_roles( "moose_feeder" );
531 The more specific a role, the earlier it will be checked. Let's say
532 moose feeders are now restricted to only the C<feed_moose> action,
533 while moose trainers get access everywhere:
535 Zoo->deny_access_unless( "/moose_cage", [qw/moose_trainer/] );
536 Zoo->allow_access_if( "/moose_cage/feed_moose", [qw/moose_feeder/]);
538 When the C<feed_moose> action is accessed the second check will be
539 made. If the user is a C<moose_feeder>, then access will be
540 immediately granted. Otherwise, the next rule in line will be tested -
541 the one checking for a C<moose_trainer>. If this rule is not
542 satisfied, access will be immediately denied.
544 Rules applied to the same path will be checked in the order they were
547 Lastly, handling access denial events is done by creating an
548 C<access_denied> private action:
550 sub access_denied : Private {
551 my ( $self, $c, $action ) = @_;
554 This action works much like auto, in that it is inherited across
555 namespaces (not like object oriented code). This means that the
556 C<access_denied> action which is B<nearest> to the action which was
557 blocked will be triggered.
559 If this action does not exist, an error will be thrown, which you can
560 clean up in your C<end> private action instead.
562 Also, it's important to note that if you restrict access to "/" then
563 C<end>, C<default>, etc. will also be restricted.
565 MyApp->acl_allow_root_internals;
567 will create rules that permit access to C<end>, C<begin>, and C<auto> in the
568 root of your app (but not in any other controller).
572 Models are where application data belongs. Catalyst is exteremely
573 flexible with the kind of models that it can use. The recipes here
576 =head2 Using existing DBIC (etc.) classes with Catalyst
578 Many people have existing Model classes that they would like to use
579 with Catalyst (or, conversely, they want to write Catalyst models that
580 can be used outside of Catalyst, e.g. in a cron job). It's trivial to
581 write a simple component in Catalyst that slurps in an outside Model:
583 package MyApp::Model::DB;
585 use base qw/Catalyst::Model::DBIC::Schema/;
588 schema_class => 'Some::DBIC::Schema',
589 connect_info => ['dbi:SQLite:foo.db', '', '', {AutoCommit=>1}];
594 and that's it! Now C<Some::DBIC::Schema> is part of your
595 Cat app as C<MyApp::Model::DB>.
597 =head2 DBIx::Class as a Catalyst Model
599 See L<Catalyst::Model::DBIC::Schema>.
601 =head2 Create accessors to preload static data once per server instance
603 When you have data that you want to load just once from the model at
604 startup, instead of for each request, use mk_group_accessors to
605 create accessors and tie them to resultsets in your package that
606 inherits from DBIx::Class::Schema:
609 use base qw/DBIx::Class::Schema/;
610 __PACKAGE__->register_class('RESULTSOURCEMONIKER',
611 'My::Schema::RESULTSOURCE');
612 __PACKAGE__->mk_group_accessors('simple' =>
613 qw(ACCESSORNAME1 ACCESSORNAME2 ACCESSORNAMEn));
616 my ($self, @rest) = @_;
617 $self->next::method(@rest);
618 # $self is now a live My::Schema object, complete with DB connection
620 $self->ACCESSORNAME1([ $self->resultset('RESULTSOURCEMONIKER')->all ]);
621 $self->ACCESSORNAME2([ $self->resultset('RESULTSOURCEMONIKER')->search({ COLUMN => { '<' => '30' } })->all ]);
622 $self->ACCESSORNAMEn([ $self->resultset('RESULTSOURCEMONIKER')->find(1) ]);
627 and now in the controller, you can now access any of these without a
630 $c->stash->{something} = $c->model('My::Schema')->schema->ACCESSORNAME;
635 Unlike SOAP, XMLRPC is a very simple (and elegant) web-services
636 protocol, exchanging small XML messages like these:
641 TE: deflate,gzip;q=0.3
642 Connection: TE, close
646 User-Agent: SOAP::Lite/Perl/0.60
648 Content-Type: text/xml
650 <?xml version="1.0" encoding="UTF-8"?>
652 <methodName>add</methodName>
654 <param><value><int>1</int></value></param>
655 <param><value><int>2</int></value></param>
662 Date: Tue, 20 Dec 2005 07:45:55 GMT
664 Content-Type: text/xml
668 <?xml version="1.0" encoding="us-ascii"?>
671 <param><value><int>3</int></value></param>
675 Now follow these few steps to implement the application:
677 1. Install Catalyst (5.61 or later), Catalyst::Plugin::XMLRPC (0.06 or
678 later) and SOAP::Lite (for XMLRPCsh.pl).
680 2. Create an application framework:
686 3. Add the XMLRPC plugin to MyApp.pm
688 use Catalyst qw/-Debug Static::Simple XMLRPC/;
690 4. Add an API controller
692 % ./script/myapp_create.pl controller API
694 5. Add a XMLRPC redispatch method and an add method with Remote
695 attribute to lib/MyApp/Controller/API.pm
698 my ( $self, $c ) = @_;
703 my ( $self, $c, $a, $b ) = @_;
707 The default action is the entry point for each XMLRPC request. It will
708 redispatch every request to methods with Remote attribute in the same
711 The C<add> method is not a traditional action; it has no private or
712 public path. Only the XMLRPC dispatcher knows it exists.
714 6. That's it! You have built your first web service. Let's test it with
715 XMLRPCsh.pl (part of SOAP::Lite):
717 % ./script/myapp_server.pl
719 % XMLRPCsh.pl http://127.0.0.1:3000/api
720 Usage: method[(parameters)]
722 --- XMLRPC RESULT ---
727 Your return data type is usually auto-detected, but you can easily
728 enforce a specific one.
731 my ( $self, $c, $a, $b ) = @_;
732 return RPC::XML::int->new( $a + $b );
737 Views pertain to the display of your application. As with models,
738 Catalyst is uncommonly flexible. The recipes below are just a start.
740 =head2 Catalyst::View::TT
742 One of the first things you probably want to do when starting a new
743 Catalyst application is set up your View. Catalyst doesn't care how you
744 display your data; you can choose to generate HTML, PDF files, or plain
747 Most Catalyst applications use a template system to generate their HTML,
748 and though there are several template systems available,
749 L<Template Toolkit|Template> is probably the most popular.
751 Once again, the Catalyst developers have done all the hard work, and
752 made things easy for the rest of us. Catalyst::View::TT provides the
753 interface to Template Toolkit, and provides Helpers which let us set it
754 up that much more easily.
756 =head3 Creating your View
758 Catalyst::View::TT provides two different helpers for us to use: TT and
763 Create a basic Template Toolkit View using the provided helper script:
765 script/myapp_create.pl view TT TT
767 This will create lib/MyApp/View/MyView.pm, which is going to be pretty
768 empty to start. However, it sets everything up that you need to get
769 started. You can now define which template you want and forward to your
773 my ( $self, $c ) = @_;
775 $c->stash->{template} = 'hello.tt';
777 $c->forward( $c->view('TT') );
780 In practice you wouldn't do the forwarding manually, but would
781 use L<Catalyst::Action::RenderView>.
785 Although the TT helper does create a functional, working view, you may
786 find yourself having to create the same template files and changing the
787 same options every time you create a new application. The TTSite helper
788 saves us even more time by creating the basic templates and setting some
789 common options for us.
791 Once again, you can use the helper script:
793 script/myapp_create.pl view TT TTSite
795 This time, the helper sets several options for us in the generated View.
797 __PACKAGE__->config({
798 CATALYST_VAR => 'Catalyst',
800 MyApp->path_to( 'root', 'src' ),
801 MyApp->path_to( 'root', 'lib' )
803 PRE_PROCESS => 'config/main',
804 WRAPPER => 'site/wrapper',
805 ERROR => 'error.tt2',
813 INCLUDE_PATH defines the directories that Template Toolkit should search
814 for the template files.
818 PRE_PROCESS is used to process configuration options which are common to
823 WRAPPER is a file which is processed with each template, usually used to
824 easily provide a common header and footer for every page.
828 In addition to setting these options, the TTSite helper also created the
829 template and config files for us! In the 'root' directory, you'll notice
830 two new directories: src and lib.
832 Several configuration files in root/lib/config are called by PRE_PROCESS.
834 The files in root/lib/site are the site-wide templates, called by
835 WRAPPER, and display the html framework, control the layout, and provide
836 the templates for the header and footer of your page. Using the template
837 organization provided makes it much easier to standardize pages and make
838 changes when they are (inevitably) needed.
840 The template files that you will create for your application will go
841 into root/src, and you don't need to worry about putting the the <html>
842 or <head> sections; just put in the content. The WRAPPER will the rest
843 of the page around your template for you.
848 Of course, having the template system include the header and footer for
849 you isn't all that we want our templates to do. We need to be able to
850 put data into our templates, and have it appear where and how we want
851 it, right? That's where the stash comes in.
853 In our controllers, we can add data to the stash, and then access it
854 from the template. For instance:
857 my ( $self, $c ) = @_;
859 $c->stash->{name} = 'Adam';
861 $c->stash->{template} = 'hello.tt';
863 $c->forward( $c->view('TT') );
868 <strong>Hello, [% name %]!</strong>
870 When you view this page, it will display "Hello, Adam!"
872 All of the information in your stash is available, by its name/key, in
873 your templates. And your data don't have to be plain, old, boring
874 scalars. You can pass array references and hash references, too.
879 my ( $self, $c ) = @_;
881 $c->stash->{names} = [ 'Adam', 'Dave', 'John' ];
883 $c->stash->{template} = 'hello.tt';
885 $c->forward( $c->view('TT') );
890 [% FOREACH name IN names %]
891 <strong>Hello, [% name %]!</strong><br />
894 This allowed us to loop through each item in the arrayref, and display a
895 line for each name that we have.
897 This is the most basic usage, but Template Toolkit is quite powerful,
898 and allows you to truly keep your presentation logic separate from the
899 rest of your application.
903 One of my favorite things about Catalyst is the ability to move an
904 application around without having to worry that everything is going to
905 break. One of the areas that used to be a problem was with the http
906 links in your template files. For example, suppose you have an
907 application installed at http://www.domain.com/Calendar. The links point
908 to "/Calendar", "/Calendar/2005", "/Calendar/2005/10", etc. If you move
909 the application to be at http://www.mydomain.com/Tools/Calendar, then
910 all of those links will suddenly break.
912 That's where $c->uri_for() comes in. This function will merge its
913 parameters with either the base location for the app, or its current
914 namespace. Let's take a look at a couple of examples.
916 In your template, you can use the following:
918 <a href="[% c.uri_for('/login') %]">Login Here</a>
920 Although the parameter starts with a forward slash, this is relative
921 to the application root, not the webserver root. This is important to
922 remember. So, if your application is installed at
923 http://www.domain.com/Calendar, then the link would be
924 http://www.mydomain.com/Calendar/Login. If you move your application
925 to a different domain or path, then that link will still be correct.
929 <a href="[% c.uri_for('2005','10', '24') %]">October, 24 2005</a>
931 The first parameter does NOT have a forward slash, and so it will be
932 relative to the current namespace. If the application is installed at
933 http://www.domain.com/Calendar. and if the template is called from
934 MyApp::Controller::Display, then the link would become
935 http://www.domain.com/Calendar/Display/2005/10/24.
937 If you want to link to a parent uri of your current namespace you can
938 prefix the arguments with multiple '../':
940 <a href="[% c.uri_for('../../view', stashed_object.id) %]">User view</a>
942 Once again, this allows you to move your application around without
943 having to worry about broken links. But there's something else, as
944 well. Since the links are generated by uri_for, you can use the same
945 template file by several different controllers, and each controller
946 will get the links that its supposed to. Since we believe in Don't
947 Repeat Yourself, this is particularly helpful if you have common
948 elements in your site that you want to keep in one file.
952 L<http://search.cpan.org/perldoc?Catalyst>
954 L<http://search.cpan.org/perldoc?Catalyst%3A%3AView%3A%3ATT>
956 L<http://search.cpan.org/perldoc?Template>
958 =head2 Adding RSS feeds
960 Adding RSS feeds to your Catalyst applications is simple. We'll see two
961 different aproaches here, but the basic premise is that you forward to
962 the normal view action first to get the objects, then handle the output
965 =head3 Using TT templates
967 This is the aproach used in Agave (L<http://dev.rawmode.org/>).
972 $c->stash->{template}='rss.tt';
975 Then you need a template. Here's the one from Agave:
977 <?xml version="1.0" encoding="UTF-8"?>
978 <rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/">
980 <title>[ [% blog.name || c.config.name || "Agave" %] ] RSS Feed</title>
981 <link>[% base %]</link>
982 <description>Recent posts</description>
983 <language>en-us</language>
985 [% WHILE (post = posts.next) %]
987 <title>[% post.title %]</title>
988 <description>[% post.formatted_teaser|html%]</description>
989 <pubDate>[% post.pub_date %]</pubDate>
990 <guid>[% post.full_uri %]</guid>
991 <link>[% post.full_uri %]</link>
992 <dc:creator>[% post.author.screenname %]</dc:creator>
998 =head3 Using XML::Feed
1000 A more robust solution is to use L<XML::Feed>, as was done in the Catalyst
1001 Advent Calendar. Assuming we have a C<view> action that populates
1002 'entries' with some DBIx::Class iterator, the code would look something
1007 $c->forward('view'); # get the entries
1009 my $feed = XML::Feed->new('RSS');
1010 $feed->title( $c->config->{name} . ' RSS Feed' );
1011 $feed->link( $c->req->base ); # link to the site.
1012 $feed->description('Catalyst advent calendar'); Some description
1014 # Process the entries
1015 while( my $entry = $c->stash->{entries}->next ) {
1016 my $feed_entry = XML::Feed::Entry->new('RSS');
1017 $feed_entry->title($entry->title);
1018 $feed_entry->link( $c->uri_for($entry->link) );
1019 $feed_entry->issued( DateTime->from_epoch(epoch => $entry->created) );
1020 $feed->add_entry($feed_entry);
1022 $c->res->body( $feed->as_xml );
1025 A little more code in the controller, but with this approach you're
1026 pretty sure to get something that validates.
1028 Note that for both of the above aproaches, you'll need to set the
1029 content type like this:
1031 $c->res->content_type('application/rss+xml');
1035 You could generalize the second variant easily by replacing 'RSS' with a
1036 variable, so you can generate Atom feeds with the same code.
1038 Now, go ahead and make RSS feeds for all your stuff. The world *needs*
1039 updates on your goldfish!
1041 =head2 Forcing the browser to download content
1043 Sometimes you need your application to send content for download. For
1044 example, you can generate a comma-separated values (CSV) file for your
1045 users to download and import into their spreadsheet program.
1047 Let's say you have an C<Orders> controller which generates a CSV file
1048 in the C<export> action (i.e., C<http://localhost:3000/orders/export>):
1050 sub export : Local Args(0) {
1051 my ( $self, $c ) = @_;
1053 # In a real application, you'd generate this from the database
1054 my $csv = "1,5.99\n2,29.99\n3,3.99\n";
1056 $c->res->content_type('text/comma-separated-values');
1057 $c->res->body($csv);
1060 Normally the browser uses the last part of the URI to generate a
1061 filename for data it cannot display. In this case your browser would
1062 likely ask you to save a file named C<export>.
1064 Luckily you can have the browser download the content with a specific
1065 filename by setting the C<Content-Disposition> header:
1067 my $filename = 'Important Orders.csv';
1068 $c->res->header('Content-Disposition', qq[attachment; filename="$filename"]);
1070 Note the use of quotes around the filename; this ensures that any
1071 spaces in the filename are handled by the browser.
1073 Put this right before calling C<< $c->res->body >> and your browser
1074 will download a file named C<Important Orders.csv> instead of
1077 You can also use this to have the browser download content which it
1078 normally displays, such as JPEG images or even HTML. Just be sure to
1079 set the appropriate content type and disposition.
1084 Controllers are the main point of communication between the web server
1085 and your application. Here we explore some aspects of how they work.
1091 A Catalyst application is driven by one or more Controller
1092 modules. There are a number of ways that Catalyst can decide which of
1093 the methods in your controller modules it should call. Controller
1094 methods are also called actions, because they determine how your
1095 catalyst application should (re-)act to any given URL. When the
1096 application is started up, catalyst looks at all your actions, and
1097 decides which URLs they map to.
1099 =head3 Type attributes
1101 Each action is a normal method in your controller, except that it has an
1102 L<attribute|attributes>
1103 attached. These can be one of several types.
1105 Assume our Controller module starts with the following package declaration:
1107 package MyApp::Controller::Buckets;
1109 and we are running our application on localhost, port 3000 (the test
1116 A Path attribute also takes an argument, this can be either a relative
1117 or an absolute path. A relative path will be relative to the
1118 controller namespace, an absolute path will represent an exact
1121 sub my_handles : Path('handles') { .. }
1125 http://localhost:3000/buckets/handles
1129 sub my_handles : Path('/handles') { .. }
1133 http://localhost:3000/handles
1135 See also: L<Catalyst::DispatchType::Path>
1139 When using a Local attribute, no parameters are needed, instead, the
1140 name of the action is matched in the URL. The namespaces created by
1141 the name of the controller package is always part of the URL.
1143 sub my_handles : Local { .. }
1147 http://localhost:3000/buckets/my_handles
1151 A Global attribute is similar to a Local attribute, except that the
1152 namespace of the controller is ignored, and matching starts at root.
1154 sub my_handles : Global { .. }
1158 http://localhost:3000/my_handles
1162 By now you should have figured that a Regex attribute is just what it
1163 sounds like. This one takes a regular expression, and matches starting
1164 from root. These differ from the rest as they can match multiple URLs.
1166 sub my_handles : Regex('^handles') { .. }
1170 http://localhost:3000/handles
1174 http://localhost:3000/handles_and_other_parts
1178 See also: L<Catalyst::DispatchType::Regex>
1182 A LocalRegex is similar to a Regex, except it only matches below the current
1183 controller namespace.
1185 sub my_handles : LocalRegex(^handles') { .. }
1189 http://localhost:3000/buckets/handles
1193 http://localhost:3000/buckets/handles_and_other_parts
1199 See L<Catalyst::DispatchType::Chained> for a description of how the chained
1200 dispatch type works.
1204 Last but not least, there is the Private attribute, which allows you
1205 to create your own internal actions, which can be forwarded to, but
1206 won't be matched as URLs.
1208 sub my_handles : Private { .. }
1210 becomes nothing at all..
1212 Catalyst also predefines some special Private actions, which you can
1213 override, these are:
1219 The default action will be called, if no other matching action is
1220 found. If you don't have one of these in your namespace, or any sub
1221 part of your namespace, you'll get an error page instead. If you want
1222 to find out where it was the user was trying to go, you can look in
1223 the request object using C<< $c->req->path >>.
1225 sub default :Path { .. }
1227 works for all unknown URLs, in this controller namespace, or every one
1228 if put directly into MyApp.pm.
1232 The index action is called when someone tries to visit the exact
1233 namespace of your controller. If index, default and matching Path
1234 actions are defined, then index will be used instead of default and
1237 sub index :Path :Args(0) { .. }
1241 http://localhost:3000/buckets
1245 The begin action is called at the beginning of every request involving
1246 this namespace directly, before other matching actions are called. It
1247 can be used to set up variables/data for this particular part of your
1248 app. A single begin action is called, its always the one most relevant
1249 to the current namespace.
1251 sub begin : Private { .. }
1255 http://localhost:3000/bucket/(anything)?
1261 Like begin, this action is always called for the namespace it is in,
1262 after every other action has finished. It is commonly used to forward
1263 processing to the View component. A single end action is called, its
1264 always the one most relevant to the current namespace.
1267 sub end : Private { .. }
1269 is called once after any actions when
1271 http://localhost:3000/bucket/(anything)?
1277 Lastly, the auto action is magic in that B<every> auto action in the
1278 chain of paths up to and including the ending namespace, will be
1279 called. (In contrast, only one of the begin/end/default actions will
1280 be called, the relevant one).
1282 package MyApp::Controller::Root;
1283 sub auto : Private { .. }
1287 sub auto : Private { .. }
1289 will both be called when visiting
1291 http://localhost:3000/bucket/(anything)?
1297 =head3 A word of warning
1299 You can put root actions in your main MyApp.pm file, but this is deprecated,
1300 please put your actions into your Root controller.
1304 A graphical flowchart of how the dispatcher works can be found on the wiki at
1305 L<http://dev.catalyst.perl.org/attachment/wiki/WikiStart/catalyst-flow.png>.
1307 =head2 DRY Controllers with Chained actions
1309 Imagine that you would like the following paths in your application:
1313 =item B<< /cd/<ID>/track/<ID> >>
1315 Displays info on a particular track.
1317 In the case of a multi-volume CD, this is the track sequence.
1319 =item B<< /cd/<ID>/volume/<ID>/track/<ID> >>
1321 Displays info on a track on a specific volume.
1325 Here is some example code, showing how to do this with chained controllers:
1327 package CD::Controller;
1328 use base qw/Catalyst::Controller/;
1330 sub root : Chained('/') PathPart('/cd') CaptureArgs(1) {
1331 my ($self, $c, $cd_id) = @_;
1332 $c->stash->{cd_id} = $cd_id;
1333 $c->stash->{cd} = $self->model('CD')->find_by_id($cd_id);
1336 sub trackinfo : Chained('track') PathPart('') Args(0) RenderView {
1337 my ($self, $c) = @_;
1340 package CD::Controller::ByTrackSeq;
1341 use base qw/CD::Controller/;
1343 sub track : Chained('root') PathPart('track') CaptureArgs(1) {
1344 my ($self, $c, $track_seq) = @_;
1345 $c->stash->{track} = $self->stash->{cd}->find_track_by_seq($track_seq);
1348 package CD::Controller::ByTrackVolNo;
1349 use base qw/CD::Controller/;
1351 sub volume : Chained('root') PathPart('volume') CaptureArgs(1) {
1352 my ($self, $c, $volume) = @_;
1353 $c->stash->{volume} = $volume;
1356 sub track : Chained('volume') PathPart('track') CaptureArgs(1) {
1357 my ($self, $c, $track_no) = @_;
1358 $c->stash->{track} = $self->stash->{cd}->find_track_by_vol_and_track_no(
1359 $c->stash->{volume}, $track_no
1363 Note that adding other actions (i.e. chain endpoints) which operate on a track
1364 is simply a matter of adding a new sub to CD::Controller - no code is duplicated,
1365 even though there are two different methods of looking up a track.
1367 This technique can be expanded as needed to fulfil your requirements - for example,
1368 if you inherit the first action of a chain from a base class, then mixing in a
1369 different base class can be used to duplicate an entire URL hieratchy at a different
1370 point within your application.
1372 =head2 Component-based Subrequests
1374 See L<Catalyst::Plugin::SubRequest>.
1378 =head3 Single file upload with Catalyst
1380 To implement uploads in Catalyst, you need to have a HTML form similar to
1383 <form action="/upload" method="post" enctype="multipart/form-data">
1384 <input type="hidden" name="form_submit" value="yes">
1385 <input type="file" name="my_file">
1386 <input type="submit" value="Send">
1389 It's very important not to forget C<enctype="multipart/form-data"> in
1392 Catalyst Controller module 'upload' action:
1394 sub upload : Global {
1395 my ($self, $c) = @_;
1397 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1399 if ( my $upload = $c->request->upload('my_file') ) {
1401 my $filename = $upload->filename;
1402 my $target = "/tmp/upload/$filename";
1404 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1405 die( "Failed to copy '$filename' to '$target': $!" );
1410 $c->stash->{template} = 'file_upload.html';
1413 =head3 Multiple file upload with Catalyst
1415 Code for uploading multiple files from one form needs a few changes:
1417 The form should have this basic structure:
1419 <form action="/upload" method="post" enctype="multipart/form-data">
1420 <input type="hidden" name="form_submit" value="yes">
1421 <input type="file" name="file1" size="50"><br>
1422 <input type="file" name="file2" size="50"><br>
1423 <input type="file" name="file3" size="50"><br>
1424 <input type="submit" value="Send">
1427 And in the controller:
1429 sub upload : Local {
1430 my ($self, $c) = @_;
1432 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1434 for my $field ( $c->req->upload ) {
1436 my $upload = $c->req->upload($field);
1437 my $filename = $upload->filename;
1438 my $target = "/tmp/upload/$filename";
1440 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1441 die( "Failed to copy '$filename' to '$target': $!" );
1446 $c->stash->{template} = 'file_upload.html';
1449 C<for my $field ($c-E<gt>req->upload)> loops automatically over all file
1450 input fields and gets input names. After that is basic file saving code,
1451 just like in single file upload.
1453 Notice: C<die>ing might not be what you want to do, when an error
1454 occurs, but it works as an example. A better idea would be to store
1455 error C<$!> in $c->stash->{error} and show a custom error template
1456 displaying this message.
1458 For more information about uploads and usable methods look at
1459 L<Catalyst::Request::Upload> and L<Catalyst::Request>.
1461 =head2 Forwarding with arguments
1463 Sometimes you want to pass along arguments when forwarding to another
1464 action. As of version 5.30, arguments can be passed in the call to
1465 C<forward>; in earlier versions, you can manually set the arguments in
1466 the Catalyst Request object:
1468 # version 5.30 and later:
1469 $c->forward('/wherever', [qw/arg1 arg2 arg3/]);
1472 $c->req->args([qw/arg1 arg2 arg3/]);
1473 $c->forward('/wherever');
1475 (See the L<Catalyst::Manual::Intro> Flow_Control section for more
1476 information on passing arguments via C<forward>.)
1478 =head2 Chained dispatch using base classes, and inner packages.
1480 package MyApp::Controller::Base;
1481 use base qw/Catalyst::Controller/;
1483 sub key1 : Chained('/')
1485 =head2 Extending RenderView (formerly DefaultEnd)
1487 The recommended approach for an C<end> action is to use
1488 L<Catalyst::Action::RenderView> (taking the place of
1489 L<Catalyst::Plugin::DefaultEnd>), which does what you usually need.
1490 However there are times when you need to add a bit to it, but don't want
1491 to write your own C<end> action.
1493 You can extend it like this:
1495 To add something to an C<end> action that is called before rendering
1496 (this is likely to be what you want), simply place it in the C<end>
1499 sub end : ActionClass('RenderView') {
1500 my ( $self, $c ) = @_;
1501 # do stuff here; the RenderView action is called afterwards
1504 To add things to an C<end> action that are called I<after> rendering,
1505 you can set it up like this:
1507 sub render : ActionClass('RenderView') { }
1510 my ( $self, $c ) = @_;
1511 $c->forward('render');
1519 The recipes below describe aspects of the deployment process,
1520 including web server engines and tips to improve application efficiency.
1522 =head2 mod_perl Deployment
1524 mod_perl is not the best solution for many applications, but we'll list some
1525 pros and cons so you can decide for yourself. The other (recommended)
1526 deployment option is FastCGI, for which see below.
1532 mod_perl is fast and your app will be loaded in memory
1533 within each Apache process.
1535 =head4 Shared memory for multiple apps
1537 If you need to run several Catalyst apps on the same server, mod_perl will
1538 share the memory for common modules.
1544 Since your application is fully loaded in memory, every Apache process will
1545 be rather large. This means a large Apache process will be tied up while
1546 serving static files, large files, or dealing with slow clients. For this
1547 reason, it is best to run a two-tiered web architecture with a lightweight
1548 frontend server passing dynamic requests to a large backend mod_perl
1553 Any changes made to the core code of your app require a full Apache restart.
1554 Catalyst does not support Apache::Reload or StatINC. This is another good
1555 reason to run a frontend web server where you can set up an
1556 C<ErrorDocument 502> page to report that your app is down for maintenance.
1558 =head4 Cannot run multiple versions of the same app
1560 It is not possible to run two different versions of the same application in
1561 the same Apache instance because the namespaces will collide.
1563 =head4 Cannot run different versions of libraries.
1565 If you have two differnet applications which run on the same machine,
1566 which need two different versions of a library then the only way to do
1567 this is to have per-vhost perl interpreters (with different library paths).
1568 This is entirely possible, but nullifies all the memory sharing benefits that
1569 you get from having multiple applications sharing the same interpreter.
1573 Now that we have that out of the way, let's talk about setting up mod_perl
1574 to run a Catalyst app.
1576 =head4 1. Install Catalyst::Engine::Apache
1578 You should install the latest versions of both Catalyst and
1579 Catalyst::Engine::Apache. The Apache engines were separated from the
1580 Catalyst core in version 5.50 to allow for updates to the engine without
1581 requiring a new Catalyst release.
1583 =head4 2. Install Apache with mod_perl
1585 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
1586 recommended. With Apache 2, make sure you are using the prefork MPM and not
1587 the worker MPM. The reason for this is that many Perl modules are not
1588 thread-safe and may have problems running within the threaded worker
1589 environment. Catalyst is thread-safe however, so if you know what you're
1590 doing, you may be able to run using worker.
1592 In Debian, the following commands should get you going.
1594 apt-get install apache2-mpm-prefork
1595 apt-get install libapache2-mod-perl2
1597 =head4 3. Configure your application
1599 Every Catalyst application will automagically become a mod_perl handler
1600 when run within mod_perl. This makes the configuration extremely easy.
1601 Here is a basic Apache 2 configuration.
1603 PerlSwitches -I/var/www/MyApp/lib
1608 PerlResponseHandler MyApp
1611 The most important line here is C<PerlModule MyApp>. This causes mod_perl
1612 to preload your entire application into shared memory, including all of your
1613 controller, model, and view classes and configuration. If you have -Debug
1614 mode enabled, you will see the startup output scroll by when you first
1617 For an example Apache 1.3 configuration, please see the documentation for
1618 L<Catalyst::Engine::Apache::MP13>.
1622 That's it, your app is now a full-fledged mod_perl application! Try it out
1623 by going to http://your.server.com/.
1625 =head3 Other Options
1627 =head4 Non-root location
1629 You may not always want to run your app at the root of your server or virtual
1630 host. In this case, it's a simple change to run at any non-root location
1635 PerlResponseHandler MyApp
1638 When running this way, it is best to make use of the C<uri_for> method in
1639 Catalyst for constructing correct links.
1641 =head4 Static file handling
1643 Static files can be served directly by Apache for a performance boost.
1645 DocumentRoot /var/www/MyApp/root
1647 SetHandler default-handler
1650 This will let all files within root/static be handled directly by Apache. In
1651 a two-tiered setup, the frontend server should handle static files.
1652 The configuration to do this on the frontend will vary.
1654 The same is accomplished in lighttpd with the following snippet:
1656 $HTTP["url"] !~ "^/(?:img/|static/|css/|favicon.ico$)" {
1660 "socket" => "/tmp/myapp.socket",
1661 "check-local" => "disable",
1667 Which serves everything in the img, static, css directories
1668 statically, as well as the favicon file.
1670 Note the path of the application needs to be stated explicitly in the
1671 web server configuration for both these recipes.
1673 =head2 Catalyst on shared hosting
1675 So, you want to put your Catalyst app out there for the whole world to
1676 see, but you don't want to break the bank. There is an answer - if you
1677 can get shared hosting with FastCGI and a shell, you can install your
1678 Catalyst app in a local directory on your shared host. First, run
1680 perl -MCPAN -e shell
1682 and go through the standard CPAN configuration process. Then exit out
1683 without installing anything. Next, open your .bashrc and add
1685 export PATH=$HOME/local/bin:$HOME/local/script:$PATH
1686 perlversion=`perl -v | grep 'built for' | awk '{print $4}' | sed -e 's/v//;'`
1687 export PERL5LIB=$HOME/local/share/perl/$perlversion:$HOME/local/lib/perl/$perlversion:$HOME/local/lib:$PERL5LIB
1689 and log out, then back in again (or run C<". .bashrc"> if you
1690 prefer). Finally, edit C<.cpan/CPAN/MyConfig.pm> and add
1692 'make_install_arg' => qq[SITEPREFIX=$ENV{HOME}/local],
1693 'makepl_arg' => qq[INSTALLDIRS=site install_base=$ENV{HOME}/local],
1695 Now you can install the modules you need using CPAN as normal; they
1696 will be installed into your local directory, and perl will pick them
1697 up. Finally, change directory into the root of your virtual host and
1698 symlink your application's script directory in:
1700 cd path/to/mydomain.com
1701 ln -s ~/lib/MyApp/script script
1703 And add the following lines to your .htaccess file (assuming the server
1704 is setup to handle .pl as fcgi - you may need to rename the script to
1705 myapp_fastcgi.fcgi and/or use a SetHandler directive):
1708 RewriteCond %{REQUEST_URI} !^/?script/myapp_fastcgi.pl
1709 RewriteRule ^(.*)$ script/myapp_fastcgi.pl/$1 [PT,L]
1711 Now C<http://mydomain.com/> should now Just Work. Congratulations, now
1712 you can tell your friends about your new website (or in our case, tell
1713 the client it's time to pay the invoice :) )
1715 =head2 FastCGI Deployment
1717 FastCGI is a high-performance extension to CGI. It is suitable
1718 for production environments.
1724 FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you;
1725 your app runs as multiple persistent processes ready to receive connections
1726 from the web server.
1730 When using external FastCGI servers, your application runs as a standalone
1731 application server. It may be restarted independently from the web server.
1732 This allows for a more robust environment and faster reload times when
1733 pushing new app changes. The frontend server can even be configured to
1734 display a friendly "down for maintenance" page while the application is
1737 =head4 Load-balancing
1739 You can launch your application on multiple backend servers and allow the
1740 frontend web server to load-balance between all of them. And of course, if
1741 one goes down, your app continues to run fine.
1743 =head4 Multiple versions of the same app
1745 Each FastCGI application is a separate process, so you can run different
1746 versions of the same app on a single server.
1748 =head4 Can run with threaded Apache
1750 Since your app is not running inside of Apache, the faster mpm_worker module
1751 can be used without worrying about the thread safety of your application.
1755 You may have to disable mod_deflate. If you experience page hangs with
1756 mod_fastcgi then remove deflate.load and deflate.conf from mods-enabled/
1758 =head4 More complex environment
1760 With FastCGI, there are more things to monitor and more processes running
1761 than when using mod_perl.
1765 =head4 1. Install Apache with mod_fastcgi
1767 mod_fastcgi for Apache is a third party module, and can be found at
1768 L<http://www.fastcgi.com/>. It is also packaged in many distributions,
1769 for example, libapache2-mod-fastcgi in Debian. You will also need to install
1770 the L<FCGI> module from cpan.
1772 Important Note! If you experience difficulty properly rendering pages,
1773 try disabling Apache's mod_deflate (Deflate Module), e.g. 'a2dismod deflate'.
1775 =head4 2. Configure your application
1777 # Serve static content directly
1778 DocumentRoot /var/www/MyApp/root
1779 Alias /static /var/www/MyApp/root/static
1781 FastCgiServer /var/www/MyApp/script/myapp_fastcgi.pl -processes 3
1782 Alias /myapp/ /var/www/MyApp/script/myapp_fastcgi.pl/
1784 # Or, run at the root
1785 Alias / /var/www/MyApp/script/myapp_fastcgi.pl/
1787 The above commands will launch 3 app processes and make the app available at
1790 =head3 Standalone server mode
1792 While not as easy as the previous method, running your app as an external
1793 server gives you much more flexibility.
1795 First, launch your app as a standalone server listening on a socket.
1797 script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5 -p /tmp/myapp.pid -d
1799 You can also listen on a TCP port if your web server is not on the same
1802 script/myapp_fastcgi.pl -l :8080 -n 5 -p /tmp/myapp.pid -d
1804 You will probably want to write an init script to handle starting/stopping
1805 of the app using the pid file.
1807 Now, we simply configure Apache to connect to the running server.
1809 # 502 is a Bad Gateway error, and will occur if the backend server is down
1810 # This allows us to display a friendly static page that says "down for
1812 Alias /_errors /var/www/MyApp/root/error-pages
1813 ErrorDocument 502 /_errors/502.html
1815 FastCgiExternalServer /tmp/myapp.fcgi -socket /tmp/myapp.socket
1816 Alias /myapp/ /tmp/myapp.fcgi/
1818 # Or, run at the root
1819 Alias / /tmp/myapp.fcgi/
1823 L<Catalyst::Engine::FastCGI>.
1825 =head2 Development server deployment
1827 The development server is a mini web server written in perl. If you
1828 expect a low number of hits or you don't need mod_perl/FastCGI speed,
1829 you could use the development server as the application server with a
1830 lightweight proxy web server at the front. However, consider using
1831 L<Catalyst::Engine::HTTP::Prefork> for this kind of deployment instead, since
1832 it can better handle multiple concurrent requests without forking, or can
1833 prefork a set number of servers for improved performance.
1837 As this is an application server setup, the pros are the same as
1838 FastCGI (with the exception of speed).
1843 The development server is what you create your code on, so if it works
1844 here, it should work in production!
1850 Not as fast as mod_perl or FastCGI. Needs to fork for each request
1851 that comes in - make sure static files are served by the web server to
1856 =head4 Start up the development server
1858 script/myapp_server.pl -p 8080 -k -f -pidfile=/tmp/myapp.pid
1860 You will probably want to write an init script to handle stop/starting
1861 the app using the pid file.
1863 =head4 Configuring Apache
1865 Make sure mod_proxy is enabled and add:
1867 # Serve static content directly
1868 DocumentRoot /var/www/MyApp/root
1869 Alias /static /var/www/MyApp/root/static
1877 # Need to specifically stop these paths from being passed to proxy
1879 ProxyPass /favicon.ico !
1881 ProxyPass / http://localhost:8080/
1882 ProxyPassReverse / http://localhost:8080/
1884 # This is optional if you'd like to show a custom error page
1885 # if the proxy is not available
1886 ErrorDocument 502 /static/error_pages/http502.html
1888 You can wrap the above within a VirtualHost container if you want
1889 different apps served on the same host.
1891 =head2 Quick deployment: Building PAR Packages
1893 You have an application running on your development box, but then you
1894 have to quickly move it to another one for
1895 demonstration/deployment/testing...
1897 PAR packages can save you from a lot of trouble here. They are usual Zip
1898 files that contain a blib tree; you can even include all prereqs and a
1899 perl interpreter by setting a few flags!
1901 =head3 Follow these few points to try it out!
1903 1. Install Catalyst and PAR 0.89 (or later)
1905 % perl -MCPAN -e 'install Catalyst'
1907 % perl -MCPAN -e 'install PAR'
1910 2. Create a application
1916 Recent versions of Catalyst (5.62 and up) include
1917 L<Module::Install::Catalyst>, which simplifies the process greatly. From the shell in your application directory:
1922 You can customise the PAR creation process by special "catalyst_par_*" commands
1923 available from L<Module::Install::Catalyst>. You can add these commands in your
1924 Makefile.PL just before the line containing "catalyst;"
1926 #Makefile.PL example with extra PAR options
1927 use inc::Module::Install;
1930 all_from 'lib\MyApp.pm';
1932 requires 'Catalyst::Runtime' => '5.80005';
1937 catalyst_par_core(1); # bundle perl core modules in the resulting PAR
1938 catalyst_par_multiarch(1); # build a multi-architecture PAR file
1939 catalyst_par_classes(qw/
1940 Some::Additional::Module
1942 /); # specify additional modules you want to be included into PAR
1945 install_script glob('script/*.pl');
1949 Congratulations! Your package "myapp.par" is ready, the following
1950 steps are just optional.
1952 3. Test your PAR package with "parl" (no typo)
1956 [parl] myapp[.par] [script] [arguments]
1959 parl myapp.par myapp_server.pl -r
1969 % parl myapp.par myapp_server.pl
1970 You can connect to your server at http://localhost:3000
1972 Yes, this nifty little starter application gets automatically included.
1973 You can also use "catalyst_par_script('myapp_server.pl')" to set a
1974 default script to execute.
1976 6. Want to create a binary that includes the Perl interpreter?
1978 % pp -o myapp myapp.par
1979 % ./myapp myapp_server.pl
1980 You can connect to your server at http://localhost:3000
1982 =head2 Serving static content
1984 Serving static content in Catalyst used to be somewhat tricky; the use
1985 of L<Catalyst::Plugin::Static::Simple> makes everything much easier.
1986 This plugin will automatically serve your static content during development,
1987 but allows you to easily switch to Apache (or other server) in a
1988 production environment.
1990 =head3 Introduction to Static::Simple
1992 Static::Simple is a plugin that will help to serve static content for your
1993 application. By default, it will serve most types of files, excluding some
1994 standard Template Toolkit extensions, out of your B<root> file directory. All
1995 files are served by path, so if B<images/me.jpg> is requested, then
1996 B<root/images/me.jpg> is found and served.
2000 Using the plugin is as simple as setting your use line in MyApp.pm to include:
2002 use Catalyst qw/Static::Simple/;
2004 and already files will be served.
2008 Static content is best served from a single directory within your root
2009 directory. Having many different directories such as C<root/css> and
2010 C<root/images> requires more code to manage, because you must separately
2011 identify each static directory--if you decide to add a C<root/js>
2012 directory, you'll need to change your code to account for it. In
2013 contrast, keeping all static directories as subdirectories of a main
2014 C<root/static> directory makes things much easier to manage. Here's an
2015 example of a typical root directory structure:
2019 root/controller/stuff.tt
2022 root/static/css/main.css
2023 root/static/images/logo.jpg
2024 root/static/js/code.js
2027 All static content lives under C<root/static>, with everything else being
2028 Template Toolkit files.
2034 You may of course want to change the default locations, and make
2035 Static::Simple look somewhere else, this is as easy as:
2037 MyApp->config->{static}->{include_path} = [
2038 MyApp->config->{root},
2042 When you override include_path, it will not automatically append the
2043 normal root path, so you need to add it yourself if you still want
2044 it. These will be searched in order given, and the first matching file
2047 =item Static directories
2049 If you want to force some directories to be only static, you can set
2050 them using paths relative to the root dir, or regular expressions:
2052 MyApp->config->{static}->{dirs} = [
2057 =item File extensions
2059 By default, the following extensions are not served (that is, they will
2060 be processed by Catalyst): B<tmpl, tt, tt2, html, xhtml>. This list can
2063 MyApp->config->{static}->{ignore_extensions} = [
2064 qw/tmpl tt tt2 html xhtml/
2067 =item Ignoring directories
2069 Entire directories can be ignored. If used with include_path,
2070 directories relative to the include_path dirs will also be ignored:
2072 MyApp->config->{static}->{ignore_dirs} = [ qw/tmpl css/ ];
2076 =head3 More information
2078 L<http://search.cpan.org/dist/Catalyst-Plugin-Static-Simple/>
2080 =head3 Serving manually with the Static plugin with HTTP::Daemon (myapp_server.pl)
2082 In some situations you might want to control things more directly,
2083 using L<Catalyst::Plugin::Static>.
2085 In your main application class (MyApp.pm), load the plugin:
2087 use Catalyst qw/-Debug FormValidator Static OtherPlugin/;
2089 You will also need to make sure your end method does I<not> forward
2090 static content to the view, perhaps like this:
2093 my ( $self, $c ) = @_;
2095 $c->forward( 'MyApp::View::TT' )
2096 unless ( $c->res->body || !$c->stash->{template} );
2099 This code will only forward to the view if a template has been
2100 previously defined by a controller and if there is not already data in
2101 C<$c-E<gt>res-E<gt>body>.
2103 Next, create a controller to handle requests for the /static path. Use
2104 the Helper to save time. This command will create a stub controller as
2105 C<lib/MyApp/Controller/Static.pm>.
2107 $ script/myapp_create.pl controller Static
2109 Edit the file and add the following methods:
2111 # serve all files under /static as static files
2112 sub default : Path('/static') {
2113 my ( $self, $c ) = @_;
2115 # Optional, allow the browser to cache the content
2116 $c->res->headers->header( 'Cache-Control' => 'max-age=86400' );
2118 $c->serve_static; # from Catalyst::Plugin::Static
2121 # also handle requests for /favicon.ico
2122 sub favicon : Path('/favicon.ico') {
2123 my ( $self, $c ) = @_;
2128 You can also define a different icon for the browser to use instead of
2129 favicon.ico by using this in your HTML header:
2131 <link rel="icon" href="/static/myapp.ico" type="image/x-icon" />
2133 =head3 Common problems with the Static plugin
2135 The Static plugin makes use of the C<shared-mime-info> package to
2136 automatically determine MIME types. This package is notoriously
2137 difficult to install, especially on win32 and OS X. For OS X the easiest
2138 path might be to install Fink, then use C<apt-get install
2139 shared-mime-info>. Restart the server, and everything should be fine.
2141 Make sure you are using the latest version (>= 0.16) for best
2142 results. If you are having errors serving CSS files, or if they get
2143 served as text/plain instead of text/css, you may have an outdated
2144 shared-mime-info version. You may also wish to simply use the following
2145 code in your Static controller:
2147 if ($c->req->path =~ /css$/i) {
2148 $c->serve_static( "text/css" );
2153 =head3 Serving Static Files with Apache
2155 When using Apache, you can bypass Catalyst and any Static
2156 plugins/controllers controller by intercepting requests for the
2157 C<root/static> path at the server level. All that is required is to
2158 define a DocumentRoot and add a separate Location block for your static
2159 content. Here is a complete config for this application under mod_perl
2163 use lib qw(/var/www/MyApp/lib);
2168 ServerName myapp.example.com
2169 DocumentRoot /var/www/MyApp/root
2171 SetHandler perl-script
2174 <LocationMatch "/(static|favicon.ico)">
2175 SetHandler default-handler
2179 And here's a simpler example that'll get you started:
2181 Alias /static/ "/my/static/files/"
2182 <Location "/static">
2188 Catalyst makes it easy to employ several different types of caching to
2189 speed up your applications.
2191 =head3 Cache Plugins
2193 There are three wrapper plugins around common CPAN cache modules:
2194 Cache::FastMmap, Cache::FileCache, and Cache::Memcached. These can be
2195 used to cache the result of slow operations.
2197 The Catalyst Advent Calendar uses the FileCache plugin to cache the
2198 rendered XHTML version of the source POD document. This is an ideal
2199 application for a cache because the source document changes
2200 infrequently but may be viewed many times.
2202 use Catalyst qw/Cache::FileCache/;
2207 sub render_pod : Local {
2208 my ( self, $c ) = @_;
2210 # the cache is keyed on the filename and the modification time
2211 # to check for updates to the file.
2212 my $file = $c->path_to( 'root', '2005', '11.pod' );
2213 my $mtime = ( stat $file )->mtime;
2215 my $cached_pod = $c->cache->get("$file $mtime");
2216 if ( !$cached_pod ) {
2217 $cached_pod = do_slow_pod_rendering();
2218 # cache the result for 12 hours
2219 $c->cache->set( "$file $mtime", $cached_pod, '12h' );
2221 $c->stash->{pod} = $cached_pod;
2224 We could actually cache the result forever, but using a value such as 12 hours
2225 allows old entries to be automatically expired when they are no longer needed.
2229 Another method of caching is to cache the entire HTML page. While this is
2230 traditionally handled by a front-end proxy server like Squid, the Catalyst
2231 PageCache plugin makes it trivial to cache the entire output from
2232 frequently-used or slow actions.
2234 Many sites have a busy content-filled front page that might look something
2235 like this. It probably takes a while to process, and will do the exact same
2236 thing for every single user who views the page.
2238 sub front_page : Path('/') {
2239 my ( $self, $c ) = @_;
2241 $c->forward( 'get_news_articles' );
2242 $c->forward( 'build_lots_of_boxes' );
2243 $c->forward( 'more_slow_stuff' );
2245 $c->stash->{template} = 'index.tt';
2248 We can add the PageCache plugin to speed things up.
2250 use Catalyst qw/Cache::FileCache PageCache/;
2252 sub front_page : Path ('/') {
2253 my ( $self, $c ) = @_;
2255 $c->cache_page( 300 );
2257 # same processing as above
2260 Now the entire output of the front page, from <html> to </html>, will be
2261 cached for 5 minutes. After 5 minutes, the next request will rebuild the
2262 page and it will be re-cached.
2264 Note that the page cache is keyed on the page URI plus all parameters, so
2265 requests for / and /?foo=bar will result in different cache items. Also,
2266 only GET requests will be cached by the plugin.
2268 You can even get that front-end Squid proxy to help out by enabling HTTP
2269 headers for the cached page.
2271 MyApp->config->{page_cache}->{set_http_headers} = 1;
2273 This would now set the following headers so proxies and browsers may cache
2274 the content themselves.
2276 Cache-Control: max-age=($expire_time - time)
2277 Expires: $expire_time
2278 Last-Modified: $cache_created_time
2280 =head3 Template Caching
2282 Template Toolkit provides support for caching compiled versions of your
2283 templates. To enable this in Catalyst, use the following configuration.
2284 TT will cache compiled templates keyed on the file mtime, so changes will
2285 still be automatically detected.
2287 package MyApp::View::TT;
2291 use base 'Catalyst::View::TT';
2293 __PACKAGE__->config(
2294 COMPILE_DIR => '/tmp/template_cache',
2301 See the documentation for each cache plugin for more details and other
2302 available configuration options.
2304 L<Catalyst::Plugin::Cache::FastMmap>
2305 L<Catalyst::Plugin::Cache::FileCache>
2306 L<Catalyst::Plugin::Cache::Memcached>
2307 L<Catalyst::Plugin::PageCache>
2308 L<http://search.cpan.org/dist/Template-Toolkit/lib/Template/Manual/Config.pod#Caching_and_Compiling_Options>
2312 Testing is an integral part of the web application development
2313 process. Tests make multi developer teams easier to coordinate, and
2314 they help ensure that there are no nasty surprises after upgrades or
2319 Catalyst provides a convenient way of testing your application during
2320 development and before deployment in a real environment.
2322 C<Catalyst::Test> makes it possible to run the same tests both locally
2323 (without an external daemon) and against a remote server via HTTP.
2327 Let's examine a skeleton application's C<t/> directory:
2329 mundus:~/MyApp chansen$ ls -l t/
2331 -rw-r--r-- 1 chansen chansen 95 18 Dec 20:50 01app.t
2332 -rw-r--r-- 1 chansen chansen 190 18 Dec 20:50 02pod.t
2333 -rw-r--r-- 1 chansen chansen 213 18 Dec 20:50 03podcoverage.t
2339 Verifies that the application loads, compiles, and returns a successful
2344 Verifies that all POD is free from errors. Only executed if the C<TEST_POD>
2345 environment variable is true.
2347 =item C<03podcoverage.t>
2349 Verifies that all methods/functions have POD coverage. Only executed if the
2350 C<TEST_POD> environment variable is true.
2354 =head3 Creating tests
2356 mundus:~/MyApp chansen$ cat t/01app.t | perl -ne 'printf( "%2d %s", $., $_ )'
2357 1 use Test::More tests => 2;
2358 2 use_ok( Catalyst::Test, 'MyApp' );
2360 4 ok( request('/')->is_success );
2362 The first line declares how many tests we are going to run, in this case
2363 two. The second line tests and loads our application in test mode. The
2364 fourth line verifies that our application returns a successful response.
2366 C<Catalyst::Test> exports two functions, C<request> and C<get>. Each can
2367 take three different arguments:
2371 =item A string which is a relative or absolute URI.
2373 request('/my/path');
2374 request('http://www.host.com/my/path');
2376 =item An instance of C<URI>.
2378 request( URI->new('http://www.host.com/my/path') );
2380 =item An instance of C<HTTP::Request>.
2382 request( HTTP::Request->new( GET => 'http://www.host.com/my/path') );
2386 C<request> returns an instance of C<HTTP::Response> and C<get> returns the
2387 content (body) of the response.
2389 =head3 Running tests locally
2391 mundus:~/MyApp chansen$ CATALYST_DEBUG=0 TEST_POD=1 prove --lib lib/ t/
2392 t/01app............ok
2393 t/02pod............ok
2394 t/03podcoverage....ok
2395 All tests successful.
2396 Files=3, Tests=4, 2 wallclock secs ( 1.60 cusr + 0.36 csys = 1.96 CPU)
2398 C<CATALYST_DEBUG=0> ensures that debugging is off; if it's enabled you
2399 will see debug logs between tests.
2401 C<TEST_POD=1> enables POD checking and coverage.
2403 C<prove> A command-line tool that makes it easy to run tests. You can
2404 find out more about it from the links below.
2406 =head3 Running tests remotely
2408 mundus:~/MyApp chansen$ CATALYST_SERVER=http://localhost:3000/ prove --lib lib/ t/01app.t
2410 All tests successful.
2411 Files=1, Tests=2, 0 wallclock secs ( 0.40 cusr + 0.01 csys = 0.41 CPU)
2413 C<CATALYST_SERVER=http://localhost:3000/> is the absolute deployment URI of
2414 your application. In C<CGI> or C<FastCGI> it should be the host and path
2417 =head3 C<Test::WWW::Mechanize> and Catalyst
2419 Be sure to check out C<Test::WWW::Mechanize::Catalyst>. It makes it easy to
2420 test HTML, forms and links. A short example of usage:
2422 use Test::More tests => 6;
2423 use_ok( Test::WWW::Mechanize::Catalyst, 'MyApp' );
2425 my $mech = Test::WWW::Mechanize::Catalyst->new;
2426 $mech->get_ok("http://localhost/", 'Got index page');
2427 $mech->title_like( qr/^MyApp on Catalyst/, 'Got right index title' );
2428 ok( $mech->find_link( text_regex => qr/^Wiki/i ), 'Found link to Wiki' );
2429 ok( $mech->find_link( text_regex => qr/^Mailing-List/i ), 'Found link to Mailing-List' );
2430 ok( $mech->find_link( text_regex => qr/^IRC channel/i ), 'Found link to IRC channel' );
2432 =head3 Further Reading
2436 =item Catalyst::Test
2438 L<http://search.cpan.org/dist/Catalyst/lib/Catalyst/Test.pm>
2440 =item Test::WWW::Mechanize::Catalyst
2442 L<http://search.cpan.org/dist/Test-WWW-Mechanize-Catalyst/lib/Test/WWW/Mechanize/Catalyst.pm>
2444 =item Test::WWW::Mechanize
2446 L<http://search.cpan.org/dist/Test-WWW-Mechanize/Mechanize.pm>
2448 =item WWW::Mechanize
2450 L<http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm>
2452 =item LWP::UserAgent
2454 L<http://search.cpan.org/dist/libwww-perl/lib/LWP/UserAgent.pm>
2458 L<http://search.cpan.org/dist/libwww-perl/lib/HTML/Form.pm>
2462 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Message.pm>
2466 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request.pm>
2468 =item HTTP::Request::Common
2470 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request/Common.pm>
2472 =item HTTP::Response
2474 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Response.pm>
2478 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Status.pm>
2482 L<http://search.cpan.org/dist/URI/URI.pm>
2486 L<http://search.cpan.org/dist/Test-Simple/lib/Test/More.pm>
2490 L<http://search.cpan.org/dist/Test-Pod/Pod.pm>
2492 =item Test::Pod::Coverage
2494 L<http://search.cpan.org/dist/Test-Pod-Coverage/Coverage.pm>
2496 =item prove (Test::Harness)
2498 L<http://search.cpan.org/dist/Test-Harness/bin/prove>
2502 =head3 More Information
2504 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::Roles>
2505 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::ACL>
2509 Catalyst Contributors, see Catalyst.pm
2513 This library is free software. You can redistribute it and/or modify it under
2514 the same terms as Perl itself.