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->param("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::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);
267 To restrict access to any action, you can use the C<check_user_roles> method:
269 sub restricted : Local {
270 my ( $self, $c ) = @_;
272 $c->detach("unauthorized")
273 unless $c->check_user_roles( "admin" );
275 # do something restricted here
278 You can also use the C<assert_user_roles> method. This just gives an
279 error if the current user does not have one of the required roles:
281 sub also_restricted : Global {
282 my ( $self, $c ) = @_;
283 $c->assert_user_roles( qw/ user admin / );
286 =head2 Authentication/Authorization
288 This is done in several steps:
294 Getting the user to identify themselves, by giving you some piece of
295 information known only to you and the user. Then you can assume that
296 the user is who they say they are. This is called B<credential
301 Making sure the user only accesses functions you want them to
302 access. This is done by checking the verified users data against your
303 internal list of groups, or allowed persons for the current page.
309 The Catalyst Authentication system is made up of many interacting
310 modules, to give you the most flexibility possible.
312 =head4 Credential verifiers
314 A Credential module tables the user input, and passes it to a Store,
315 or some other system, for verification. Typically, a user object is
316 created by either this module or the Store and made accessible by a
317 C<< $c->user >> call.
321 Password - Simple username/password checking.
322 HTTPD - Checks using basic HTTP auth.
323 TypeKey - Check using the typekey system.
325 =head3 Storage backends
327 A Storage backend contains the actual data representing the users. It
328 is queried by the credential verifiers. Updating the store is not done
329 within this system, you will need to do it yourself.
333 DBIC - Storage using a database.
334 Minimal - Storage using a simple hash (for testing).
338 A User object is created by either the storage backend or the
339 credential verifier, and filled with the retrieved user information.
343 Hash - A simple hash of keys and values.
345 =head3 ACL authorization
347 ACL stands for Access Control List. The ACL plugin allows you to
348 regulate access on a path by path basis, by listing which users, or
349 roles, have access to which paths.
351 =head3 Roles authorization
353 Authorization by roles is for assigning users to groups, which can
354 then be assigned to ACLs, or just checked when needed.
358 When you have chosen your modules, all you need to do is call the C<<
359 $c->authenticate >> method. If called with no parameters, it will try to find
360 suitable parameters, such as B<username> and B<password>, or you can
361 pass it these values.
363 =head3 Checking roles
365 Role checking is done by using the C<< $c->check_user_roles >> method,
366 this will check using the currently logged in user (via C<< $c->user
367 >>). You pass it the name of a role to check, and it returns true if
368 the user is a member.
374 use namespace::autoclean;
375 extends qw/Catalyst/;
376 use Catalyst qw/Authentication
377 Authorization::Roles/;
380 'Plugin::Authentication' => {
396 if ( my $user = $c->req->param("user")
397 and my $password = $c->req->param("password") )
399 if ( $c->authenticate( username => $user, password => $password ) ) {
400 $c->res->body( "hello " . $c->user->name );
410 sub restricted : Local {
411 my ( $self, $c ) = @_;
413 $c->detach("unauthorized")
414 unless $c->check_user_roles( "admin" );
416 # do something restricted here
419 =head3 Using authentication in a testing environment
421 Ideally, to write tests for authentication/authorization code one
422 would first set up a test database with known data, then use
423 L<Test::WWW::Mechanize::Catalyst> to simulate a user logging
424 in. Unfortunately the former can be rather awkward, which is why it's
425 a good thing that the authentication framework is so flexible.
427 Instead of using a test database, one can simply change the
428 authentication store to something a bit easier to deal with in a
429 testing environment. Additionally, this has the advantage of not
430 modifying one's database, which can be problematic if one forgets to
431 use the testing instead of production database.
435 # FIXME - Out of date
436 use Catalyst::Plugin::Authentication::Store::Minimal::Backend;
438 # Sets up the user `test_user' with password `test_pass'
439 MyApp->default_auth_store(
440 Catalyst::Plugin::Authentication::Store::Minimal::Backend->new({
441 test_user => { password => 'test_pass' },
445 Now, your test code can call C<$c->login('test_user', 'test_pass')> and
446 successfully login, without messing with the database at all.
448 =head3 More information
450 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authentication> has a longer explanation.
456 Authorization is the step that comes after
457 authentication. Authentication establishes that the user agent is
458 really representing the user we think it's representing, and then
459 authorization determines what this user is allowed to do.
461 =head3 Role Based Access Control
463 Under role based access control each user is allowed to perform any
464 number of roles. For example, at a zoo no one but specially trained
465 personnel can enter the moose cage (Mynd you, møøse bites kan be
466 pretty nasti!). For example:
468 package Zoo::Controller::MooseCage;
470 sub feed_moose : Local {
471 my ( $self, $c ) = @_;
473 $c->model( "Moose" )->eat( $c->req->param("food") );
476 With this action, anyone can just come into the moose cage and feed
477 the moose, which is a very dangerous thing. We need to restrict this
478 action, so that only a qualified moose feeder can perform that action.
480 The Authorization::Roles plugin let's us perform role based access
481 control checks. Let's load it:
483 use parent qw/Catalyst/;
489 And now our action should look like this:
491 sub feed_moose : Local {
492 my ( $self, $c ) = @_;
494 if ( $c->check_roles( "moose_feeder" ) ) {
495 $c->model( "Moose" )->eat( $c->req->param("food") );
497 $c->stash->{error} = "unauthorized";
501 This checks C<< $c->user >>, and only if the user has B<all> the roles
502 in the list, a true value is returned.
504 C<check_roles> has a sister method, C<assert_roles>, which throws an
505 exception if any roles are missing.
507 Some roles that might actually make sense in, say, a forum application:
521 each with a distinct task (system administration versus content
524 =head3 Access Control Lists
526 Checking for roles all the time can be tedious and error prone.
528 The Authorization::ACL plugin let's us declare where we'd like checks
529 to be done automatically for us.
531 For example, we may want to completely block out anyone who isn't a
532 C<moose_feeder> from the entire C<MooseCage> controller:
534 Zoo->deny_access_unless( "/moose_cage", [qw/moose_feeder/] );
536 The role list behaves in the same way as C<check_roles>. However, the
537 ACL plugin isn't limited to just interacting with the Roles plugin. We
538 can use a code reference instead. For example, to allow either moose
539 trainers or moose feeders into the moose cage, we can create a more
542 Zoo->deny_access_unless( "/moose_cage", sub {
544 $c->check_roles( "moose_trainer" ) || $c->check_roles( "moose_feeder" );
547 The more specific a role, the earlier it will be checked. Let's say
548 moose feeders are now restricted to only the C<feed_moose> action,
549 while moose trainers get access everywhere:
551 Zoo->deny_access_unless( "/moose_cage", [qw/moose_trainer/] );
552 Zoo->allow_access_if( "/moose_cage/feed_moose", [qw/moose_feeder/]);
554 When the C<feed_moose> action is accessed the second check will be
555 made. If the user is a C<moose_feeder>, then access will be
556 immediately granted. Otherwise, the next rule in line will be tested -
557 the one checking for a C<moose_trainer>. If this rule is not
558 satisfied, access will be immediately denied.
560 Rules applied to the same path will be checked in the order they were
563 Lastly, handling access denial events is done by creating an
564 C<access_denied> private action:
566 sub access_denied : Private {
567 my ( $self, $c, $action ) = @_;
570 This action works much like auto, in that it is inherited across
571 namespaces (not like object oriented code). This means that the
572 C<access_denied> action which is B<nearest> to the action which was
573 blocked will be triggered.
575 If this action does not exist, an error will be thrown, which you can
576 clean up in your C<end> private action instead.
578 Also, it's important to note that if you restrict access to "/" then
579 C<end>, C<default>, etc will also be restricted.
581 MyApp->acl_allow_root_internals;
583 will create rules that permit access to C<end>, C<begin>, and C<auto> in the
584 root of your app (but not in any other controller).
588 Models are where application data belongs. Catalyst is exteremely
589 flexible with the kind of models that it can use. The recipes here
592 =head2 Using existing DBIC (etc.) classes with Catalyst
594 Many people have existing Model classes that they would like to use
595 with Catalyst (or, conversely, they want to write Catalyst models that
596 can be used outside of Catalyst, e.g. in a cron job). It's trivial to
597 write a simple component in Catalyst that slurps in an outside Model:
599 package MyApp::Model::DB;
600 use base qw/Catalyst::Model::DBIC::Schema/;
602 schema_class => 'Some::DBIC::Schema',
603 connect_info => ['dbi:SQLite:foo.db', '', '', {AutoCommit=>1}];
607 and that's it! Now C<Some::DBIC::Schema> is part of your
608 Cat app as C<MyApp::Model::DB>.
610 =head2 DBIx::Class as a Catalyst Model
612 See L<Catalyst::Model::DBIC::Schema>.
614 =head2 Create accessors to preload static data once per server instance
616 When you have data that you want to load just once from the model at
617 server load instead of for each request, use mk_group_accessors to
618 create accessors and tie them to resultsets in your package that
619 inherits from DBIx::Class::Schema
622 use base qw/DBIx::Class::Schema/;
623 __PACKAGE__->register_class('RESULTSOURCEMONIKER',
624 'My::Schema::RESULTSOURCE');
625 __PACKAGE__->mk_group_accessors('simple' =>
626 qw(ACCESSORNAME1 ACCESSORNAME2 ACCESSORNAMEn));
629 my ($self, @rest) = @_;
630 $self->next::method(@rest);
631 # $self is now a live My::Schema object, complete with DB connection
633 $self->ACCESSORNAME1([ $self->resultset('RESULTSOURCEMONIKER')->all ]);
634 $self->ACCESSORNAME2([ $self->resultset('RESULTSOURCEMONIKER')->search({ COLUMN => { '<' => '30' } })->all ]);
635 $self->ACCESSORNAMEn([ $self->resultset('RESULTSOURCEMONIKER')->find(1) ]);
640 and now in the controller, you can now access any of these without a
643 $c->stash->{something} = $c->model('My::Schema')->schema->ACCESSORNAMEn;
648 Unlike SOAP, XMLRPC is a very simple (and imo elegant) web-services
649 protocol, exchanging small XML messages like these:
654 TE: deflate,gzip;q=0.3
655 Connection: TE, close
659 User-Agent: SOAP::Lite/Perl/0.60
661 Content-Type: text/xml
663 <?xml version="1.0" encoding="UTF-8"?>
665 <methodName>add</methodName>
667 <param><value><int>1</int></value></param>
668 <param><value><int>2</int></value></param>
675 Date: Tue, 20 Dec 2005 07:45:55 GMT
677 Content-Type: text/xml
681 <?xml version="1.0" encoding="us-ascii"?>
684 <param><value><int>3</int></value></param>
688 Now follow these few steps to implement the application:
690 1. Install Catalyst (5.61 or later), Catalyst::Plugin::XMLRPC (0.06 or
691 later) and SOAP::Lite (for XMLRPCsh.pl).
693 2. Create an application framework:
699 3. Add the XMLRPC plugin to MyApp.pm
701 use Catalyst qw/-Debug Static::Simple XMLRPC/;
703 4. Add an API controller
705 % ./script/myapp_create.pl controller API
707 5. Add a XMLRPC redispatch method and an add method with Remote
708 attribute to lib/MyApp/Controller/API.pm
711 my ( $self, $c ) = @_;
716 my ( $self, $c, $a, $b ) = @_;
720 The default action is the entry point for each XMLRPC request. It will
721 redispatch every request to methods with Remote attribute in the same
724 The C<add> method is not a traditional action; it has no private or
725 public path. Only the XMLRPC dispatcher knows it exists.
727 6. That's it! You have built your first web service. Let's test it with
728 XMLRPCsh.pl (part of SOAP::Lite):
730 % ./script/myapp_server.pl
732 % XMLRPCsh.pl http://127.0.0.1:3000/api
733 Usage: method[(parameters)]
735 --- XMLRPC RESULT ---
740 Your return data type is usually auto-detected, but you can easily
741 enforce a specific one.
744 my ( $self, $c, $a, $b ) = @_;
745 return RPC::XML::int->new( $a + $b );
750 Views pertain to the display of your application. As with models,
751 catalyst is uncommonly flexible. The recipes below are just a start.
753 =head2 Catalyst::View::TT
755 One of the first things you probably want to do when starting a new
756 Catalyst application is set up your View. Catalyst doesn't care how you
757 display your data; you can choose to generate HTML, PDF files, or plain
760 Most Catalyst applications use a template system to generate their HTML,
761 and though there are several template systems available, Template
762 Toolkit is probably the most popular.
764 Once again, the Catalyst developers have done all the hard work, and
765 made things easy for the rest of us. Catalyst::View::TT provides the
766 interface to Template Toolkit, and provides Helpers which let us set it
767 up that much more easily.
769 =head3 Creating your View
771 Catalyst::View::TT provides two different helpers for us to use: TT and
776 Create a basic Template Toolkit View using the provided helper script:
778 script/myapp_create.pl view TT TT
780 This will create lib/MyApp/View/MyView.pm, which is going to be pretty
781 empty to start. However, it sets everything up that you need to get
782 started. You can now define which template you want and forward to your
786 my ( $self, $c ) = @_;
788 $c->stash->{template} = 'hello.tt';
790 $c->forward( $c->view('TT') );
793 In practice you wouldn't do the forwarding manually, but would
794 use L<Catalyst::Action::RenderView>.
798 Although the TT helper does create a functional, working view, you may
799 find yourself having to create the same template files and changing the
800 same options every time you create a new application. The TTSite helper
801 saves us even more time by creating the basic templates and setting some
802 common options for us.
804 Once again, you can use the helper script:
806 script/myapp_create.pl view TT TTSite
808 This time, the helper sets several options for us in the generated View.
810 __PACKAGE__->config({
811 CATALYST_VAR => 'Catalyst',
813 MyApp->path_to( 'root', 'src' ),
814 MyApp->path_to( 'root', 'lib' )
816 PRE_PROCESS => 'config/main',
817 WRAPPER => 'site/wrapper',
818 ERROR => 'error.tt2',
826 INCLUDE_PATH defines the directories that Template Toolkit should search
827 for the template files.
831 PRE_PROCESS is used to process configuration options which are common to
836 WRAPPER is a file which is processed with each template, usually used to
837 easily provide a common header and footer for every page.
841 In addition to setting these options, the TTSite helper also created the
842 template and config files for us! In the 'root' directory, you'll notice
843 two new directories: src and lib.
845 Several configuration files in root/lib/config are called by PRE_PROCESS.
847 The files in root/lib/site are the site-wide templates, called by
848 WRAPPER, and display the html framework, control the layout, and provide
849 the templates for the header and footer of your page. Using the template
850 organization provided makes it much easier to standardize pages and make
851 changes when they are (inevitably) needed.
853 The template files that you will create for your application will go
854 into root/src, and you don't need to worry about putting the the <html>
855 or <head> sections; just put in the content. The WRAPPER will the rest
856 of the page around your template for you.
861 Of course, having the template system include the header and footer for
862 you isn't all that we want our templates to do. We need to be able to
863 put data into our templates, and have it appear where and how we want
864 it, right? That's where the stash comes in.
866 In our controllers, we can add data to the stash, and then access it
867 from the template. For instance:
870 my ( $self, $c ) = @_;
872 $c->stash->{name} = 'Adam';
874 $c->stash->{template} = 'hello.tt';
876 $c->forward( $c->view('TT') );
881 <strong>Hello, [% name %]!</strong>
883 When you view this page, it will display "Hello, Adam!"
885 All of the information in your stash is available, by its name/key, in
886 your templates. And your data don't have to be plain, old, boring
887 scalars. You can pass array references and hash references, too.
892 my ( $self, $c ) = @_;
894 $c->stash->{names} = [ 'Adam', 'Dave', 'John' ];
896 $c->stash->{template} = 'hello.tt';
898 $c->forward( $c->view('TT') );
903 [% FOREACH name IN names %]
904 <strong>Hello, [% name %]!</strong><br />
907 This allowed us to loop through each item in the arrayref, and display a
908 line for each name that we have.
910 This is the most basic usage, but Template Toolkit is quite powerful,
911 and allows you to truly keep your presentation logic separate from the
912 rest of your application.
916 One of my favorite things about Catalyst is the ability to move an
917 application around without having to worry that everything is going to
918 break. One of the areas that used to be a problem was with the http
919 links in your template files. For example, suppose you have an
920 application installed at http://www.domain.com/Calendar. The links point
921 to "/Calendar", "/Calendar/2005", "/Calendar/2005/10", etc. If you move
922 the application to be at http://www.mydomain.com/Tools/Calendar, then
923 all of those links will suddenly break.
925 That's where $c->uri_for() comes in. This function will merge its
926 parameters with either the base location for the app, or its current
927 namespace. Let's take a look at a couple of examples.
929 In your template, you can use the following:
931 <a href="[% c.uri_for('/login') %]">Login Here</a>
933 Although the parameter starts with a forward slash, this is relative
934 to the application root, not the webserver root. This is important to
935 remember. So, if your application is installed at
936 http://www.domain.com/Calendar, then the link would be
937 http://www.mydomain.com/Calendar/Login. If you move your application
938 to a different domain or path, then that link will still be correct.
942 <a href="[% c.uri_for('2005','10', '24') %]">October, 24 2005</a>
944 The first parameter does NOT have a forward slash, and so it will be
945 relative to the current namespace. If the application is installed at
946 http://www.domain.com/Calendar. and if the template is called from
947 MyApp::Controller::Display, then the link would become
948 http://www.domain.com/Calendar/Display/2005/10/24.
950 If you want to link to a parent uri of your current namespace you can
951 prefix the arguments with multiple '../':
953 <a href="[% c.uri_for('../../view', stashed_object.id) %]">User view</a>
955 Once again, this allows you to move your application around without
956 having to worry about broken links. But there's something else, as
957 well. Since the links are generated by uri_for, you can use the same
958 template file by several different controllers, and each controller
959 will get the links that its supposed to. Since we believe in Don't
960 Repeat Yourself, this is particularly helpful if you have common
961 elements in your site that you want to keep in one file.
965 L<http://search.cpan.org/perldoc?Catalyst>
967 L<http://search.cpan.org/perldoc?Catalyst%3A%3AView%3A%3ATT>
969 L<http://search.cpan.org/perldoc?Template>
971 =head2 Adding RSS feeds
973 Adding RSS feeds to your Catalyst applications is simple. We'll see two
974 different aproaches here, but the basic premise is that you forward to
975 the normal view action first to get the objects, then handle the output
978 =head3 Using TT templates
980 This is the aproach used in Agave (L<http://dev.rawmode.org/>).
985 $c->stash->{template}='rss.tt';
988 Then you need a template. Here's the one from Agave:
990 <?xml version="1.0" encoding="UTF-8"?>
991 <rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/">
993 <title>[ [% blog.name || c.config.name || "Agave" %] ] RSS Feed</title>
994 <link>[% base %]</link>
995 <description>Recent posts</description>
996 <language>en-us</language>
998 [% WHILE (post = posts.next) %]
1000 <title>[% post.title %]</title>
1001 <description>[% post.formatted_teaser|html%]</description>
1002 <pubDate>[% post.pub_date %]</pubDate>
1003 <guid>[% post.full_uri %]</guid>
1004 <link>[% post.full_uri %]</link>
1005 <dc:creator>[% post.author.screenname %]</dc:creator>
1011 =head3 Using XML::Feed
1013 A more robust solution is to use XML::Feed, as was done in the Catalyst
1014 Advent Calendar. Assuming we have a C<view> action that populates
1015 'entries' with some DBIx::Class iterator, the code would look something
1020 $c->forward('view'); # get the entries
1022 my $feed = XML::Feed->new('RSS');
1023 $feed->title( $c->config->{name} . ' RSS Feed' );
1024 $feed->link( $c->req->base ); # link to the site.
1025 $feed->description('Catalyst advent calendar'); Some description
1027 # Process the entries
1028 while( my $entry = $c->stash->{entries}->next ) {
1029 my $feed_entry = XML::Feed::Entry->new('RSS');
1030 $feed_entry->title($entry->title);
1031 $feed_entry->link( $c->uri_for($entry->link) );
1032 $feed_entry->issued( DateTime->from_epoch(epoch => $entry->created) );
1033 $feed->add_entry($feed_entry);
1035 $c->res->body( $feed->as_xml );
1038 A little more code in the controller, but with this approach you're
1039 pretty sure to get something that validates.
1041 Note that for both of the above aproaches, you'll need to set the
1042 content type like this:
1044 $c->res->content_type('application/rss+xml');
1048 You could generalize the second variant easily by replacing 'RSS' with a
1049 variable, so you can generate Atom feeds with the same code.
1051 Now, go ahead and make RSS feeds for all your stuff. The world *needs*
1052 updates on your goldfish!
1054 =head2 Forcing the browser to download content
1056 Sometimes you need your application to send content for download. For
1057 example, you can generate a comma-separated values (CSV) file for your
1058 users to download and import into their spreadsheet program.
1060 Let's say you have an C<Orders> controller which generates a CSV file
1061 in the C<export> action (i.e., C<http://localhost:3000/orders/export>):
1063 sub export : Local Args(0) {
1064 my ( $self, $c ) = @_;
1066 # In a real application, you'd generate this from the database
1067 my $csv = "1,5.99\n2,29.99\n3,3.99\n";
1069 $c->res->content_type('text/comma-separated-values');
1070 $c->res->body($csv);
1073 Normally the browser uses the last part of the URI to generate a
1074 filename for data it cannot display. In this case your browser would
1075 likely ask you to save a file named C<export>.
1077 Luckily you can have the browser download the content with a specific
1078 filename by setting the C<Content-Disposition> header:
1080 my $filename = 'Important Orders.csv';
1081 $c->res->header('Content-Disposition', qq[attachment; filename="$filename"]);
1083 Note the use of quotes around the filename; this ensures that any
1084 spaces in the filename are handled by the browser.
1086 Put this right before calling C<< $c->res->body >> and your browser
1087 will download a file named C<Important Orders.csv> instead of
1090 You can also use this to have the browser download content which it
1091 normally displays, such as JPEG images or even HTML. Just be sure to
1092 set the appropriate content type and disposition.
1097 Controllers are the main point of communication between the web server
1098 and your application. Here we explore some aspects of how they work.
1100 =head2 Extending RenderView (formerly DefaultEnd)
1102 The recommended approach for an C<end> action is to use
1103 L<Catalyst::Action::RenderView> (taking the place of
1104 L<Catalyst::Plugin::DefaultEnd>), which does what you usually need.
1105 However there are times when you need to add a bit to it, but don't want
1106 to write your own C<end> action.
1108 You can extend it like this:
1110 To add something to an C<end> action that is called before rendering
1111 (this is likely to be what you want), simply place it in the C<end>
1114 sub end : ActionClass('RenderView') {
1115 my ( $self, $c ) = @_;
1116 # do stuff here; the RenderView action is called afterwards
1119 To add things to an C<end> action that are called I<after> rendering,
1120 you can set it up like this:
1122 sub render : ActionClass('RenderView') { }
1125 my ( $self, $c ) = @_;
1126 $c->forward('render');
1134 A Catalyst application is driven by one or more Controller
1135 modules. There are a number of ways that Catalyst can decide which of
1136 the methods in your controller modules it should call. Controller
1137 methods are also called actions, because they determine how your
1138 catalyst application should (re-)act to any given URL. When the
1139 application is started up, catalyst looks at all your actions, and
1140 decides which URLs they map to.
1142 =head3 Type attributes
1144 Each action is a normal method in your controller, except that it has an
1145 L<attribute|http://search.cpan.org/~nwclark/perl-5.8.7/lib/attributes.pm>
1146 attached. These can be one of several types.
1148 Assume our Controller module starts with the following package declaration:
1150 package MyApp::Controller::Buckets;
1152 and we are running our application on localhost, port 3000 (the test
1159 A Path attribute also takes an argument, this can be either a relative
1160 or an absolute path. A relative path will be relative to the
1161 controller namespace, an absolute path will represent an exact
1164 sub my_handles : Path('handles') { .. }
1168 http://localhost:3000/buckets/handles
1172 sub my_handles : Path('/handles') { .. }
1176 http://localhost:3000/handles
1178 See also: L<Catalyst::DispatchType::Path>
1182 When using a Local attribute, no parameters are needed, instead, the
1183 name of the action is matched in the URL. The namespaces created by
1184 the name of the controller package is always part of the URL.
1186 sub my_handles : Local { .. }
1190 http://localhost:3000/buckets/my_handles
1194 A Global attribute is similar to a Local attribute, except that the
1195 namespace of the controller is ignored, and matching starts at root.
1197 sub my_handles : Global { .. }
1201 http://localhost:3000/my_handles
1205 By now you should have figured that a Regex attribute is just what it
1206 sounds like. This one takes a regular expression, and matches starting
1207 from root. These differ from the rest as they can match multiple URLs.
1209 sub my_handles : Regex('^handles') { .. }
1213 http://localhost:3000/handles
1217 http://localhost:3000/handles_and_other_parts
1221 See also: L<Catalyst::DispatchType::Regex>
1225 A LocalRegex is similar to a Regex, except it only matches below the current
1226 controller namespace.
1228 sub my_handles : LocalRegex(^handles') { .. }
1232 http://localhost:3000/buckets/handles
1236 http://localhost:3000/buckets/handles_and_other_parts
1242 See L<Catalyst::DispatchType::Chained> for a description of how the chained
1243 dispatch type works.
1247 Last but not least, there is the Private attribute, which allows you
1248 to create your own internal actions, which can be forwarded to, but
1249 won't be matched as URLs.
1251 sub my_handles : Private { .. }
1253 becomes nothing at all..
1255 Catalyst also predefines some special Private actions, which you can
1256 override, these are:
1262 The default action will be called, if no other matching action is
1263 found. If you don't have one of these in your namespace, or any sub
1264 part of your namespace, you'll get an error page instead. If you want
1265 to find out where it was the user was trying to go, you can look in
1266 the request object using C<< $c->req->path >>.
1268 sub default :Path { .. }
1270 works for all unknown URLs, in this controller namespace, or every one
1271 if put directly into MyApp.pm.
1275 The index action is called when someone tries to visit the exact
1276 namespace of your controller. If index, default and matching Path
1277 actions are defined, then index will be used instead of default and
1280 sub index :Path :Args(0) { .. }
1284 http://localhost:3000/buckets
1288 The begin action is called at the beginning of every request involving
1289 this namespace directly, before other matching actions are called. It
1290 can be used to set up variables/data for this particular part of your
1291 app. A single begin action is called, its always the one most relevant
1292 to the current namespace.
1294 sub begin : Private { .. }
1298 http://localhost:3000/bucket/(anything)?
1304 Like begin, this action is always called for the namespace it is in,
1305 after every other action has finished. It is commonly used to forward
1306 processing to the View component. A single end action is called, its
1307 always the one most relevant to the current namespace.
1310 sub end : Private { .. }
1312 is called once after any actions when
1314 http://localhost:3000/bucket/(anything)?
1320 Lastly, the auto action is magic in that B<every> auto action in the
1321 chain of paths up to and including the ending namespace, will be
1322 called. (In contrast, only one of the begin/end/default actions will
1323 be called, the relevant one).
1325 package MyApp::Controller::Root;
1326 sub auto : Private { .. }
1330 sub auto : Private { .. }
1332 will both be called when visiting
1334 http://localhost:3000/bucket/(anything)?
1340 =head3 A word of warning
1342 You can put root actions in your main MyApp.pm file, but this is deprecated,
1343 please put your actions into your Root controller.
1345 =head3 More Information
1347 L<http://dev.catalyst.perl.org/wiki/FlowChart>
1349 =head2 DRY Controllers with Chained actions.
1351 Imagine that you would like the following paths in your application:
1355 =item B</cd/<ID>/track/<ID>>
1357 Displays info on a particular track.
1359 In the case of a multi-volume CD, this is the track sequence.
1361 =item B</cd/<ID>/volume/<ID>/track/<ID>>
1363 Displays info on a track on a specific volume.
1367 Here is some example code, showing how to do this with chained controllers:
1369 package CD::Controller;
1370 use base qw/Catalyst::Controller/;
1372 sub root : Chained('/') PathPart('/cd') CaptureArgs(1) {
1373 my ($self, $c, $cd_id) = @_;
1374 $c->stash->{cd_id} = $cd_id;
1375 $c->stash->{cd} = $self->model('CD')->find_by_id($cd_id);
1378 sub trackinfo : Chained('track') PathPart('') Args(0) RenderView {
1379 my ($self, $c) = @_;
1382 package CD::Controller::ByTrackSeq;
1383 use base qw/CD::Controller/;
1385 sub track : Chained('root') PathPart('track') CaptureArgs(1) {
1386 my ($self, $c, $track_seq) = @_;
1387 $c->stash->{track} = $self->stash->{cd}->find_track_by_seq($track_seq);
1390 package CD::Controller::ByTrackVolNo;
1391 use base qw/CD::Controller/;
1393 sub volume : Chained('root') PathPart('volume') CaptureArgs(1) {
1394 my ($self, $c, $volume) = @_;
1395 $c->stash->{volume} = $volume;
1398 sub track : Chained('volume') PathPart('track') CaptureArgs(1) {
1399 my ($self, $c, $track_no) = @_;
1400 $c->stash->{track} = $self->stash->{cd}->find_track_by_vol_and_track_no(
1401 $c->stash->{volume}, $track_no
1405 Note that adding other actions (i.e. chain endpoints) which operate on a track
1406 is simply a matter of adding a new sub to CD::Controller - no code is duplicated,
1407 even though there are two different methods of looking up a track.
1409 This technique can be expanded as needed to fulfil your requirements - for example,
1410 if you inherit the first action of a chain from a base class, then mixing in a
1411 different base class can be used to duplicate an entire URL hieratchy at a different
1412 point within your application.
1414 =head2 Component-based Subrequests
1416 See L<Catalyst::Plugin::SubRequest>.
1420 =head3 Single file upload with Catalyst
1422 To implement uploads in Catalyst, you need to have a HTML form similar to
1425 <form action="/upload" method="post" enctype="multipart/form-data">
1426 <input type="hidden" name="form_submit" value="yes">
1427 <input type="file" name="my_file">
1428 <input type="submit" value="Send">
1431 It's very important not to forget C<enctype="multipart/form-data"> in
1434 Catalyst Controller module 'upload' action:
1436 sub upload : Global {
1437 my ($self, $c) = @_;
1439 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1441 if ( my $upload = $c->request->upload('my_file') ) {
1443 my $filename = $upload->filename;
1444 my $target = "/tmp/upload/$filename";
1446 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1447 die( "Failed to copy '$filename' to '$target': $!" );
1452 $c->stash->{template} = 'file_upload.html';
1455 =head3 Multiple file upload with Catalyst
1457 Code for uploading multiple files from one form needs a few changes:
1459 The form should have this basic structure:
1461 <form action="/upload" method="post" enctype="multipart/form-data">
1462 <input type="hidden" name="form_submit" value="yes">
1463 <input type="file" name="file1" size="50"><br>
1464 <input type="file" name="file2" size="50"><br>
1465 <input type="file" name="file3" size="50"><br>
1466 <input type="submit" value="Send">
1469 And in the controller:
1471 sub upload : Local {
1472 my ($self, $c) = @_;
1474 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1476 for my $field ( $c->req->upload ) {
1478 my $upload = $c->req->upload($field);
1479 my $filename = $upload->filename;
1480 my $target = "/tmp/upload/$filename";
1482 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1483 die( "Failed to copy '$filename' to '$target': $!" );
1488 $c->stash->{template} = 'file_upload.html';
1491 C<for my $field ($c-E<gt>req->upload)> loops automatically over all file
1492 input fields and gets input names. After that is basic file saving code,
1493 just like in single file upload.
1495 Notice: C<die>ing might not be what you want to do, when an error
1496 occurs, but it works as an example. A better idea would be to store
1497 error C<$!> in $c->stash->{error} and show a custom error template
1498 displaying this message.
1500 For more information about uploads and usable methods look at
1501 L<Catalyst::Request::Upload> and L<Catalyst::Request>.
1503 =head2 Forwarding with arguments
1505 Sometimes you want to pass along arguments when forwarding to another
1506 action. As of version 5.30, arguments can be passed in the call to
1507 C<forward>; in earlier versions, you can manually set the arguments in
1508 the Catalyst Request object:
1510 # version 5.30 and later:
1511 $c->forward('/wherever', [qw/arg1 arg2 arg3/]);
1514 $c->req->args([qw/arg1 arg2 arg3/]);
1515 $c->forward('/wherever');
1517 (See the L<Catalyst::Manual::Intro> Flow_Control section for more
1518 information on passing arguments via C<forward>.)
1520 =head2 Chained dispatch using base classes, and inner packages.
1522 package MyApp::Controller::Base;
1523 use base qw/Catalyst::Controller/;
1525 sub key1 : Chained('/')
1529 The recipes below describe aspects of the deployment process,
1530 including web server engines and tips to improve application efficiency.
1532 =head2 mod_perl Deployment
1534 mod_perl is the best solution for many applications, but we'll list some pros
1535 and cons so you can decide for yourself. The other production deployment
1536 option is FastCGI, for which see below.
1542 mod_perl is very fast and your app will benefit from being loaded in memory
1543 within each Apache process.
1545 =head4 Shared memory for multiple apps
1547 If you need to run several Catalyst apps on the same server, mod_perl will
1548 share the memory for common modules.
1554 Since your application is fully loaded in memory, every Apache process will
1555 be rather large. This means a large Apache process will be tied up while
1556 serving static files, large files, or dealing with slow clients. For this
1557 reason, it is best to run a two-tiered web architecture with a lightweight
1558 frontend server passing dynamic requests to a large backend mod_perl
1563 Any changes made to the core code of your app require a full Apache restart.
1564 Catalyst does not support Apache::Reload or StatINC. This is another good
1565 reason to run a frontend web server where you can set up an
1566 C<ErrorDocument 502> page to report that your app is down for maintenance.
1568 =head4 Cannot run multiple versions of the same app
1570 It is not possible to run two different versions of the same application in
1571 the same Apache instance because the namespaces will collide.
1575 Now that we have that out of the way, let's talk about setting up mod_perl
1576 to run a Catalyst app.
1578 =head4 1. Install Catalyst::Engine::Apache
1580 You should install the latest versions of both Catalyst and
1581 Catalyst::Engine::Apache. The Apache engines were separated from the
1582 Catalyst core in version 5.50 to allow for updates to the engine without
1583 requiring a new Catalyst release.
1585 =head4 2. Install Apache with mod_perl
1587 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
1588 recommended. With Apache 2, make sure you are using the prefork MPM and not
1589 the worker MPM. The reason for this is that many Perl modules are not
1590 thread-safe and may have problems running within the threaded worker
1591 environment. Catalyst is thread-safe however, so if you know what you're
1592 doing, you may be able to run using worker.
1594 In Debian, the following commands should get you going.
1596 apt-get install apache2-mpm-prefork
1597 apt-get install libapache2-mod-perl2
1599 =head4 3. Configure your application
1601 Every Catalyst application will automagically become a mod_perl handler
1602 when run within mod_perl. This makes the configuration extremely easy.
1603 Here is a basic Apache 2 configuration.
1605 PerlSwitches -I/var/www/MyApp/lib
1610 PerlResponseHandler MyApp
1613 The most important line here is C<PerlModule MyApp>. This causes mod_perl
1614 to preload your entire application into shared memory, including all of your
1615 controller, model, and view classes and configuration. If you have -Debug
1616 mode enabled, you will see the startup output scroll by when you first
1619 For an example Apache 1.3 configuration, please see the documentation for
1620 L<Catalyst::Engine::Apache::MP13>.
1624 That's it, your app is now a full-fledged mod_perl application! Try it out
1625 by going to http://your.server.com/.
1627 =head3 Other Options
1629 =head4 Non-root location
1631 You may not always want to run your app at the root of your server or virtual
1632 host. In this case, it's a simple change to run at any non-root location
1637 PerlResponseHandler MyApp
1640 When running this way, it is best to make use of the C<uri_for> method in
1641 Catalyst for constructing correct links.
1643 =head4 Static file handling
1645 Static files can be served directly by Apache for a performance boost.
1647 DocumentRoot /var/www/MyApp/root
1649 SetHandler default-handler
1652 This will let all files within root/static be handled directly by Apache. In
1653 a two-tiered setup, the frontend server should handle static files.
1654 The configuration to do this on the frontend will vary.
1656 The same is accomplished in lighttpd with the following snippet:
1658 $HTTP["url"] !~ "^/(?:img/|static/|css/|favicon.ico$)" {
1662 "socket" => "/tmp/myapp.socket",
1663 "check-local" => "disable",
1669 Which serves everything in the img, static, css directories
1670 statically, as well as the favicon file.
1672 Note the path of the application needs to be stated explicitly in the
1673 web server configuration for both these recipes.
1675 =head2 Catalyst on shared hosting
1677 So, you want to put your Catalyst app out there for the whole world to
1678 see, but you don't want to break the bank. There is an answer - if you
1679 can get shared hosting with FastCGI and a shell, you can install your
1680 Catalyst app in a local directory on your shared host. First, run
1682 perl -MCPAN -e shell
1684 and go through the standard CPAN configuration process. Then exit out
1685 without installing anything. Next, open your .bashrc and add
1687 export PATH=$HOME/local/bin:$HOME/local/script:$PATH
1688 perlversion=`perl -v | grep 'built for' | awk '{print $4}' | sed -e 's/v//;'`
1689 export PERL5LIB=$HOME/local/share/perl/$perlversion:$HOME/local/lib/perl/$perlversion:$HOME/local/lib:$PERL5LIB
1691 and log out, then back in again (or run C<". .bashrc"> if you
1692 prefer). Finally, edit C<.cpan/CPAN/MyConfig.pm> and add
1694 'make_install_arg' => qq[SITEPREFIX=$ENV{HOME}/local],
1695 'makepl_arg' => qq[INSTALLDIRS=site install_base=$ENV{HOME}/local],
1697 Now you can install the modules you need using CPAN as normal; they
1698 will be installed into your local directory, and perl will pick them
1699 up. Finally, change directory into the root of your virtual host and
1700 symlink your application's script directory in:
1702 cd path/to/mydomain.com
1703 ln -s ~/lib/MyApp/script script
1705 And add the following lines to your .htaccess file (assuming the server
1706 is setup to handle .pl as fcgi - you may need to rename the script to
1707 myapp_fastcgi.fcgi and/or use a SetHandler directive):
1710 RewriteCond %{REQUEST_URI} !^/?script/myapp_fastcgi.pl
1711 RewriteRule ^(.*)$ script/myapp_fastcgi.pl/$1 [PT,L]
1713 Now C<http://mydomain.com/> should now Just Work. Congratulations, now
1714 you can tell your friends about your new website (or in our case, tell
1715 the client it's time to pay the invoice :) )
1717 =head2 FastCGI Deployment
1719 FastCGI is a high-performance extension to CGI. It is suitable
1720 for production environments.
1726 FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you;
1727 your app runs as multiple persistent processes ready to receive connections
1728 from the web server.
1732 When using external FastCGI servers, your application runs as a standalone
1733 application server. It may be restarted independently from the web server.
1734 This allows for a more robust environment and faster reload times when
1735 pushing new app changes. The frontend server can even be configured to
1736 display a friendly "down for maintenance" page while the application is
1739 =head4 Load-balancing
1741 You can launch your application on multiple backend servers and allow the
1742 frontend web server to load-balance between all of them. And of course, if
1743 one goes down, your app continues to run fine.
1745 =head4 Multiple versions of the same app
1747 Each FastCGI application is a separate process, so you can run different
1748 versions of the same app on a single server.
1750 =head4 Can run with threaded Apache
1752 Since your app is not running inside of Apache, the faster mpm_worker module
1753 can be used without worrying about the thread safety of your application.
1757 You may have to disable mod_deflate. If you experience page hangs with
1758 mod_fastcgi then remove deflate.load and deflate.conf from mods-enabled/
1760 =head4 More complex environment
1762 With FastCGI, there are more things to monitor and more processes running
1763 than when using mod_perl.
1767 =head4 1. Install Apache with mod_fastcgi
1769 mod_fastcgi for Apache is a third party module, and can be found at
1770 L<http://www.fastcgi.com/>. It is also packaged in many distributions,
1771 for example, libapache2-mod-fastcgi in Debian.
1773 =head4 2. Configure your application
1775 # Serve static content directly
1776 DocumentRoot /var/www/MyApp/root
1777 Alias /static /var/www/MyApp/root/static
1779 FastCgiServer /var/www/MyApp/script/myapp_fastcgi.pl -processes 3
1780 Alias /myapp/ /var/www/MyApp/script/myapp_fastcgi.pl/
1782 # Or, run at the root
1783 Alias / /var/www/MyApp/script/myapp_fastcgi.pl/
1785 The above commands will launch 3 app processes and make the app available at
1788 =head3 Standalone server mode
1790 While not as easy as the previous method, running your app as an external
1791 server gives you much more flexibility.
1793 First, launch your app as a standalone server listening on a socket.
1795 script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5 -p /tmp/myapp.pid -d
1797 You can also listen on a TCP port if your web server is not on the same
1800 script/myapp_fastcgi.pl -l :8080 -n 5 -p /tmp/myapp.pid -d
1802 You will probably want to write an init script to handle starting/stopping
1803 of the app using the pid file.
1805 Now, we simply configure Apache to connect to the running server.
1807 # 502 is a Bad Gateway error, and will occur if the backend server is down
1808 # This allows us to display a friendly static page that says "down for
1810 Alias /_errors /var/www/MyApp/root/error-pages
1811 ErrorDocument 502 /_errors/502.html
1813 FastCgiExternalServer /tmp/myapp.fcgi -socket /tmp/myapp.socket
1814 Alias /myapp/ /tmp/myapp.fcgi/
1816 # Or, run at the root
1817 Alias / /tmp/myapp.fcgi/
1821 L<Catalyst::Engine::FastCGI>.
1823 =head2 Development server deployment
1825 The development server is a mini web server written in perl. If you
1826 expect a low number of hits or you don't need mod_perl/FastCGI speed,
1827 you could use the development server as the application server with a
1828 lightweight proxy web server at the front. However, consider using
1829 L<Catalyst::Engine::HTTP::Prefork> for this kind of deployment instead, since
1830 it can better handle multiple concurrent requests without forking, or can
1831 prefork a set number of servers for improved performance.
1835 As this is an application server setup, the pros are the same as
1836 FastCGI (with the exception of speed).
1841 The development server is what you create your code on, so if it works
1842 here, it should work in production!
1848 Not as fast as mod_perl or FastCGI. Needs to fork for each request
1849 that comes in - make sure static files are served by the web server to
1854 =head4 Start up the development server
1856 script/myapp_server.pl -p 8080 -k -f -pidfile=/tmp/myapp.pid
1858 You will probably want to write an init script to handle stop/starting
1859 the app using the pid file.
1861 =head4 Configuring Apache
1863 Make sure mod_proxy is enabled and add:
1865 # Serve static content directly
1866 DocumentRoot /var/www/MyApp/root
1867 Alias /static /var/www/MyApp/root/static
1875 # Need to specifically stop these paths from being passed to proxy
1877 ProxyPass /favicon.ico !
1879 ProxyPass / http://localhost:8080/
1880 ProxyPassReverse / http://localhost:8080/
1882 # This is optional if you'd like to show a custom error page
1883 # if the proxy is not available
1884 ErrorDocument 502 /static/error_pages/http502.html
1886 You can wrap the above within a VirtualHost container if you want
1887 different apps served on the same host.
1889 =head2 Quick deployment: Building PAR Packages
1891 You have an application running on your development box, but then you
1892 have to quickly move it to another one for
1893 demonstration/deployment/testing...
1895 PAR packages can save you from a lot of trouble here. They are usual Zip
1896 files that contain a blib tree; you can even include all prereqs and a
1897 perl interpreter by setting a few flags!
1899 =head3 Follow these few points to try it out!
1901 1. Install Catalyst and PAR 0.89 (or later)
1903 % perl -MCPAN -e 'install Catalyst'
1905 % perl -MCPAN -e 'install PAR'
1908 2. Create a application
1914 Recent versions of Catalyst (5.62 and up) include
1915 L<Module::Install::Catalyst>, which simplifies the process greatly. From the shell in your application directory:
1920 You can customise the PAR creation process by special "catalyst_par_*" commands
1921 available from L<Module::Install::Catalyst>. You can add these commands in your
1922 Makefile.PL just before the line containing "catalyst;"
1924 #Makefile.PL example with extra PAR options
1925 use inc::Module::Install;
1928 all_from 'lib\MyApp.pm';
1930 requires 'Catalyst::Runtime' => '5.80005';
1935 catalyst_par_core(1); # bundle perl core modules in the resulting PAR
1936 catalyst_par_multiarch(1); # build a multi-architecture PAR file
1937 catalyst_par_classes(qw/
1938 Some::Additional::Module
1940 /); # specify additional modules you want to be included into PAR
1943 install_script glob('script/*.pl');
1947 Congratulations! Your package "myapp.par" is ready, the following
1948 steps are just optional.
1950 3. Test your PAR package with "parl" (no typo)
1954 [parl] myapp[.par] [script] [arguments]
1957 parl myapp.par myapp_server.pl -r
1967 % parl myapp.par myapp_server.pl
1968 You can connect to your server at http://localhost:3000
1970 Yes, this nifty little starter application gets automatically included.
1971 You can also use "catalyst_par_script('myapp_server.pl')" to set a
1972 default script to execute.
1974 6. Want to create a binary that includes the Perl interpreter?
1976 % pp -o myapp myapp.par
1977 % ./myapp myapp_server.pl
1978 You can connect to your server at http://localhost:3000
1980 =head2 Serving static content
1982 Serving static content in Catalyst used to be somewhat tricky; the use
1983 of L<Catalyst::Plugin::Static::Simple> makes everything much easier.
1984 This plugin will automatically serve your static content during development,
1985 but allows you to easily switch to Apache (or other server) in a
1986 production environment.
1988 =head3 Introduction to Static::Simple
1990 Static::Simple is a plugin that will help to serve static content for your
1991 application. By default, it will serve most types of files, excluding some
1992 standard Template Toolkit extensions, out of your B<root> file directory. All
1993 files are served by path, so if B<images/me.jpg> is requested, then
1994 B<root/images/me.jpg> is found and served.
1998 Using the plugin is as simple as setting your use line in MyApp.pm to include:
2000 use Catalyst qw/Static::Simple/;
2002 and already files will be served.
2006 Static content is best served from a single directory within your root
2007 directory. Having many different directories such as C<root/css> and
2008 C<root/images> requires more code to manage, because you must separately
2009 identify each static directory--if you decide to add a C<root/js>
2010 directory, you'll need to change your code to account for it. In
2011 contrast, keeping all static directories as subdirectories of a main
2012 C<root/static> directory makes things much easier to manage. Here's an
2013 example of a typical root directory structure:
2017 root/controller/stuff.tt
2020 root/static/css/main.css
2021 root/static/images/logo.jpg
2022 root/static/js/code.js
2025 All static content lives under C<root/static>, with everything else being
2026 Template Toolkit files.
2032 You may of course want to change the default locations, and make
2033 Static::Simple look somewhere else, this is as easy as:
2035 MyApp->config->{static}->{include_path} = [
2036 MyApp->config->{root},
2040 When you override include_path, it will not automatically append the
2041 normal root path, so you need to add it yourself if you still want
2042 it. These will be searched in order given, and the first matching file
2045 =item Static directories
2047 If you want to force some directories to be only static, you can set
2048 them using paths relative to the root dir, or regular expressions:
2050 MyApp->config->{static}->{dirs} = [
2055 =item File extensions
2057 By default, the following extensions are not served (that is, they will
2058 be processed by Catalyst): B<tmpl, tt, tt2, html, xhtml>. This list can
2061 MyApp->config->{static}->{ignore_extensions} = [
2062 qw/tmpl tt tt2 html xhtml/
2065 =item Ignoring directories
2067 Entire directories can be ignored. If used with include_path,
2068 directories relative to the include_path dirs will also be ignored:
2070 MyApp->config->{static}->{ignore_dirs} = [ qw/tmpl css/ ];
2074 =head3 More information
2076 L<http://search.cpan.org/dist/Catalyst-Plugin-Static-Simple/>
2078 =head3 Serving manually with the Static plugin with HTTP::Daemon (myapp_server.pl)
2080 In some situations you might want to control things more directly,
2081 using L<Catalyst::Plugin::Static>.
2083 In your main application class (MyApp.pm), load the plugin:
2085 use Catalyst qw/-Debug FormValidator Static OtherPlugin/;
2087 You will also need to make sure your end method does I<not> forward
2088 static content to the view, perhaps like this:
2091 my ( $self, $c ) = @_;
2093 $c->forward( 'MyApp::View::TT' )
2094 unless ( $c->res->body || !$c->stash->{template} );
2097 This code will only forward to the view if a template has been
2098 previously defined by a controller and if there is not already data in
2099 C<$c-E<gt>res-E<gt>body>.
2101 Next, create a controller to handle requests for the /static path. Use
2102 the Helper to save time. This command will create a stub controller as
2103 C<lib/MyApp/Controller/Static.pm>.
2105 $ script/myapp_create.pl controller Static
2107 Edit the file and add the following methods:
2109 # serve all files under /static as static files
2110 sub default : Path('/static') {
2111 my ( $self, $c ) = @_;
2113 # Optional, allow the browser to cache the content
2114 $c->res->headers->header( 'Cache-Control' => 'max-age=86400' );
2116 $c->serve_static; # from Catalyst::Plugin::Static
2119 # also handle requests for /favicon.ico
2120 sub favicon : Path('/favicon.ico') {
2121 my ( $self, $c ) = @_;
2126 You can also define a different icon for the browser to use instead of
2127 favicon.ico by using this in your HTML header:
2129 <link rel="icon" href="/static/myapp.ico" type="image/x-icon" />
2131 =head3 Common problems with the Static plugin
2133 The Static plugin makes use of the C<shared-mime-info> package to
2134 automatically determine MIME types. This package is notoriously
2135 difficult to install, especially on win32 and OS X. For OS X the easiest
2136 path might be to install Fink, then use C<apt-get install
2137 shared-mime-info>. Restart the server, and everything should be fine.
2139 Make sure you are using the latest version (>= 0.16) for best
2140 results. If you are having errors serving CSS files, or if they get
2141 served as text/plain instead of text/css, you may have an outdated
2142 shared-mime-info version. You may also wish to simply use the following
2143 code in your Static controller:
2145 if ($c->req->path =~ /css$/i) {
2146 $c->serve_static( "text/css" );
2151 =head3 Serving Static Files with Apache
2153 When using Apache, you can bypass Catalyst and any Static
2154 plugins/controllers controller by intercepting requests for the
2155 C<root/static> path at the server level. All that is required is to
2156 define a DocumentRoot and add a separate Location block for your static
2157 content. Here is a complete config for this application under mod_perl
2161 use lib qw(/var/www/MyApp/lib);
2166 ServerName myapp.example.com
2167 DocumentRoot /var/www/MyApp/root
2169 SetHandler perl-script
2172 <LocationMatch "/(static|favicon.ico)">
2173 SetHandler default-handler
2177 And here's a simpler example that'll get you started:
2179 Alias /static/ "/my/static/files/"
2180 <Location "/static">
2186 Catalyst makes it easy to employ several different types of caching to
2187 speed up your applications.
2189 =head3 Cache Plugins
2191 There are three wrapper plugins around common CPAN cache modules:
2192 Cache::FastMmap, Cache::FileCache, and Cache::Memcached. These can be
2193 used to cache the result of slow operations.
2195 The Catalyst Advent Calendar uses the FileCache plugin to cache the
2196 rendered XHTML version of the source POD document. This is an ideal
2197 application for a cache because the source document changes
2198 infrequently but may be viewed many times.
2200 use Catalyst qw/Cache::FileCache/;
2205 sub render_pod : Local {
2206 my ( self, $c ) = @_;
2208 # the cache is keyed on the filename and the modification time
2209 # to check for updates to the file.
2210 my $file = $c->path_to( 'root', '2005', '11.pod' );
2211 my $mtime = ( stat $file )->mtime;
2213 my $cached_pod = $c->cache->get("$file $mtime");
2214 if ( !$cached_pod ) {
2215 $cached_pod = do_slow_pod_rendering();
2216 # cache the result for 12 hours
2217 $c->cache->set( "$file $mtime", $cached_pod, '12h' );
2219 $c->stash->{pod} = $cached_pod;
2222 We could actually cache the result forever, but using a value such as 12 hours
2223 allows old entries to be automatically expired when they are no longer needed.
2227 Another method of caching is to cache the entire HTML page. While this is
2228 traditionally handled by a front-end proxy server like Squid, the Catalyst
2229 PageCache plugin makes it trivial to cache the entire output from
2230 frequently-used or slow actions.
2232 Many sites have a busy content-filled front page that might look something
2233 like this. It probably takes a while to process, and will do the exact same
2234 thing for every single user who views the page.
2236 sub front_page : Path('/') {
2237 my ( $self, $c ) = @_;
2239 $c->forward( 'get_news_articles' );
2240 $c->forward( 'build_lots_of_boxes' );
2241 $c->forward( 'more_slow_stuff' );
2243 $c->stash->{template} = 'index.tt';
2246 We can add the PageCache plugin to speed things up.
2248 use Catalyst qw/Cache::FileCache PageCache/;
2250 sub front_page : Path ('/') {
2251 my ( $self, $c ) = @_;
2253 $c->cache_page( 300 );
2255 # same processing as above
2258 Now the entire output of the front page, from <html> to </html>, will be
2259 cached for 5 minutes. After 5 minutes, the next request will rebuild the
2260 page and it will be re-cached.
2262 Note that the page cache is keyed on the page URI plus all parameters, so
2263 requests for / and /?foo=bar will result in different cache items. Also,
2264 only GET requests will be cached by the plugin.
2266 You can even get that front-end Squid proxy to help out by enabling HTTP
2267 headers for the cached page.
2269 MyApp->config->{page_cache}->{set_http_headers} = 1;
2271 This would now set the following headers so proxies and browsers may cache
2272 the content themselves.
2274 Cache-Control: max-age=($expire_time - time)
2275 Expires: $expire_time
2276 Last-Modified: $cache_created_time
2278 =head3 Template Caching
2280 Template Toolkit provides support for caching compiled versions of your
2281 templates. To enable this in Catalyst, use the following configuration.
2282 TT will cache compiled templates keyed on the file mtime, so changes will
2283 still be automatically detected.
2285 package MyApp::View::TT;
2289 use base 'Catalyst::View::TT';
2291 __PACKAGE__->config(
2292 COMPILE_DIR => '/tmp/template_cache',
2299 See the documentation for each cache plugin for more details and other
2300 available configuration options.
2302 L<Catalyst::Plugin::Cache::FastMmap>
2303 L<Catalyst::Plugin::Cache::FileCache>
2304 L<Catalyst::Plugin::Cache::Memcached>
2305 L<Catalyst::Plugin::PageCache>
2306 L<http://search.cpan.org/dist/Template-Toolkit/lib/Template/Manual/Config.pod#Caching_and_Compiling_Options>
2310 Testing is an integral part of the web application development
2311 process. Tests make multi developer teams easier to coordinate, and
2312 they help ensure that there are no nasty surprises after upgrades or
2317 Catalyst provides a convenient way of testing your application during
2318 development and before deployment in a real environment.
2320 C<Catalyst::Test> makes it possible to run the same tests both locally
2321 (without an external daemon) and against a remote server via HTTP.
2325 Let's examine a skeleton application's C<t/> directory:
2327 mundus:~/MyApp chansen$ ls -l t/
2329 -rw-r--r-- 1 chansen chansen 95 18 Dec 20:50 01app.t
2330 -rw-r--r-- 1 chansen chansen 190 18 Dec 20:50 02pod.t
2331 -rw-r--r-- 1 chansen chansen 213 18 Dec 20:50 03podcoverage.t
2337 Verifies that the application loads, compiles, and returns a successful
2342 Verifies that all POD is free from errors. Only executed if the C<TEST_POD>
2343 environment variable is true.
2345 =item C<03podcoverage.t>
2347 Verifies that all methods/functions have POD coverage. Only executed if the
2348 C<TEST_POD> environment variable is true.
2352 =head3 Creating tests
2354 mundus:~/MyApp chansen$ cat t/01app.t | perl -ne 'printf( "%2d %s", $., $_ )'
2355 1 use Test::More tests => 2;
2356 2 use_ok( Catalyst::Test, 'MyApp' );
2358 4 ok( request('/')->is_success );
2360 The first line declares how many tests we are going to run, in this case
2361 two. The second line tests and loads our application in test mode. The
2362 fourth line verifies that our application returns a successful response.
2364 C<Catalyst::Test> exports two functions, C<request> and C<get>. Each can
2365 take three different arguments:
2369 =item A string which is a relative or absolute URI.
2371 request('/my/path');
2372 request('http://www.host.com/my/path');
2374 =item An instance of C<URI>.
2376 request( URI->new('http://www.host.com/my/path') );
2378 =item An instance of C<HTTP::Request>.
2380 request( HTTP::Request->new( GET => 'http://www.host.com/my/path') );
2384 C<request> returns an instance of C<HTTP::Response> and C<get> returns the
2385 content (body) of the response.
2387 =head3 Running tests locally
2389 mundus:~/MyApp chansen$ CATALYST_DEBUG=0 TEST_POD=1 prove --lib lib/ t/
2390 t/01app............ok
2391 t/02pod............ok
2392 t/03podcoverage....ok
2393 All tests successful.
2394 Files=3, Tests=4, 2 wallclock secs ( 1.60 cusr + 0.36 csys = 1.96 CPU)
2396 C<CATALYST_DEBUG=0> ensures that debugging is off; if it's enabled you
2397 will see debug logs between tests.
2399 C<TEST_POD=1> enables POD checking and coverage.
2401 C<prove> A command-line tool that makes it easy to run tests. You can
2402 find out more about it from the links below.
2404 =head3 Running tests remotely
2406 mundus:~/MyApp chansen$ CATALYST_SERVER=http://localhost:3000/ prove --lib lib/ t/01app.t
2408 All tests successful.
2409 Files=1, Tests=2, 0 wallclock secs ( 0.40 cusr + 0.01 csys = 0.41 CPU)
2411 C<CATALYST_SERVER=http://localhost:3000/> is the absolute deployment URI of
2412 your application. In C<CGI> or C<FastCGI> it should be the host and path
2415 =head3 C<Test::WWW::Mechanize> and Catalyst
2417 Be sure to check out C<Test::WWW::Mechanize::Catalyst>. It makes it easy to
2418 test HTML, forms and links. A short example of usage:
2420 use Test::More tests => 6;
2421 use_ok( Test::WWW::Mechanize::Catalyst, 'MyApp' );
2423 my $mech = Test::WWW::Mechanize::Catalyst->new;
2424 $mech->get_ok("http://localhost/", 'Got index page');
2425 $mech->title_like( qr/^MyApp on Catalyst/, 'Got right index title' );
2426 ok( $mech->find_link( text_regex => qr/^Wiki/i ), 'Found link to Wiki' );
2427 ok( $mech->find_link( text_regex => qr/^Mailing-List/i ), 'Found link to Mailing-List' );
2428 ok( $mech->find_link( text_regex => qr/^IRC channel/i ), 'Found link to IRC channel' );
2430 =head3 Further Reading
2434 =item Catalyst::Test
2436 L<http://search.cpan.org/dist/Catalyst/lib/Catalyst/Test.pm>
2438 =item Test::WWW::Mechanize::Catalyst
2440 L<http://search.cpan.org/dist/Test-WWW-Mechanize-Catalyst/lib/Test/WWW/Mechanize/Catalyst.pm>
2442 =item Test::WWW::Mechanize
2444 L<http://search.cpan.org/dist/Test-WWW-Mechanize/Mechanize.pm>
2446 =item WWW::Mechanize
2448 L<http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm>
2450 =item LWP::UserAgent
2452 L<http://search.cpan.org/dist/libwww-perl/lib/LWP/UserAgent.pm>
2456 L<http://search.cpan.org/dist/libwww-perl/lib/HTML/Form.pm>
2460 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Message.pm>
2464 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request.pm>
2466 =item HTTP::Request::Common
2468 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request/Common.pm>
2470 =item HTTP::Response
2472 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Response.pm>
2476 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Status.pm>
2480 L<http://search.cpan.org/dist/URI/URI.pm>
2484 L<http://search.cpan.org/dist/Test-Simple/lib/Test/More.pm>
2488 L<http://search.cpan.org/dist/Test-Pod/Pod.pm>
2490 =item Test::Pod::Coverage
2492 L<http://search.cpan.org/dist/Test-Pod-Coverage/Coverage.pm>
2494 =item prove (Test::Harness)
2496 L<http://search.cpan.org/dist/Test-Harness/bin/prove>
2500 =head3 More Information
2502 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::Roles>
2503 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::ACL>
2507 Sebastian Riedel C<sri@oook.de>
2509 Danijel Milicevic C<me@danijel.de>
2511 Viljo Marrandi C<vilts@yahoo.com>
2513 Marcus Ramberg C<mramberg@cpan.org>
2515 Jesse Sheidlower C<jester@panix.com>
2517 Andy Grundman C<andy@hybridized.org>
2519 Chisel Wright C<pause@herlpacker.co.uk>
2521 Will Hawes C<info@whawes.co.uk>
2523 Gavin Henry C<ghenry@perl.me.uk>
2525 Kieren Diment C<kd@totaldatasolution.com>
2529 This document is free, you can redistribute it and/or modify it
2530 under the same terms as Perl itself.