3 Catalyst::Manual::Cookbook - Cooking with Catalyst
7 Yummy code like your mum used to bake!
13 These recipes cover some basic stuff that is worth knowing for
16 =head2 Delivering a Custom Error Page
18 By default, Catalyst will display its own error page whenever it
19 encounters an error in your application. When running under C<-Debug>
20 mode, the error page is a useful screen including the error message
21 and L<Data::Dump> output of the relevant parts of the C<$c> context
22 object. When not in C<-Debug>, users see a simple "Please come back
25 To use a custom error page, use a special C<end> method to
26 short-circuit the error processing. The following is an example; you
27 might want to adjust it further depending on the needs of your
28 application (for example, any calls to C<fillform> will probably need
29 to go into this C<end> method; see L<Catalyst::Plugin::FillInForm>).
32 my ( $self, $c ) = @_;
34 if ( scalar @{ $c->error } ) {
35 $c->stash->{errors} = $c->error;
36 for my $error ( @{ $c->error } ) {
37 $c->log->error($error);
39 $c->stash->{template} = 'errors.tt';
40 $c->forward('MyApp::View::TT');
44 return 1 if $c->response->status =~ /^3\d\d$/;
45 return 1 if $c->response->body;
47 unless ( $c->response->content_type ) {
48 $c->response->content_type('text/html; charset=utf-8');
51 $c->forward('MyApp::View::TT');
54 You can manually set errors in your code to trigger this page by calling
56 $c->error( 'You broke me!' );
58 =head2 Disable statistics
60 Just add this line to your application class if you don't want those
61 nifty statistics in your debug messages.
63 sub Catalyst::Log::info { }
65 =head2 Enable debug status in the environment
67 Normally you enable the debugging info by adding the C<-Debug> flag to
68 your C<use Catalyst> statement . However, you can also enable it using
69 environment variable, so you can (for example) get debug info without
70 modifying your application scripts. Just set C<CATALYST_DEBUG> or
71 C<E<lt>MYAPPE<gt>_DEBUG> to a true value.
75 When you have your users identified, you will want to somehow remember
76 that fact, to save them from having to identify themselves for every
77 single page. One way to do this is to send the username and password
78 parameters in every single page, but that's ugly, and won't work for
81 Sessions are a method of saving data related to some transaction, and
82 giving the whole collection a single ID. This ID is then given to the
83 user to return to us on every page they visit while logged in. The
84 usual way to do this is using a browser cookie.
86 Catalyst uses two types of plugins to represent sessions:
90 A State module is used to keep track of the state of the session
91 between the users browser, and your application.
93 A common example is the Cookie state module, which sends the browser a
94 cookie containing the session ID. It will use default value for the
95 cookie name and domain, so will "just work" when used.
99 A Store module is used to hold all the data relating to your session,
100 for example the users ID, or the items for their shopping cart. You
101 can store data in memory (FastMmap), in a file (File) or in a database
104 =head3 Authentication magic
106 If you have included the session modules in your application, the
107 Authentication modules will automagically use your session to save and
108 retrieve the user data for you.
110 =head3 Using a session
112 Once the session modules are loaded, the session is available as C<<
113 $c->session >>, and can be writen to and read from as a simple hash
120 use namespace::autoclean;
124 Session::Store::FastMmap
125 Session::State::Cookie
130 package MyApp::Controller::Foo;
132 use namespace::autoclean;
133 BEGIN { extends 'Catalyst::Controller' };
134 ## Write data into the session
136 sub add_item : Local {
137 my ( $self, $c ) = @_;
139 my $item_id = $c->req->params->{item};
141 push @{ $c->session->{items} }, $item_id;
145 ## A page later we retrieve the data from the session:
147 sub get_items : Local {
148 my ( $self, $c ) = @_;
150 $c->stash->{items_to_display} = $c->session->{items};
155 =head3 More information
157 L<http://search.cpan.org/dist/Catalyst-Plugin-Session>
159 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-Cookie>
161 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-URI>
163 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-FastMmap>
165 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-File>
167 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-DBI>
169 =head2 Configure your application
171 You configure your application with the C<config> method in your
172 application class. This can be hard-coded, or brought in from a
173 separate configuration file.
175 =head3 Using Config::General
177 L<Config::General|Config::General> is a method for creating flexible
178 and readable configuration files. It's a great way to keep your
179 Catalyst application configuration in one easy-to-understand location.
181 Now create C<myapp.conf> in your application home:
185 # session; perldoc Catalyst::Plugin::Session::FastMmap
189 storage /tmp/myapp.session
192 # emails; perldoc Catalyst::Plugin::Email
193 # this passes options as an array :(
197 This is equivalent to:
199 # configure base package
200 __PACKAGE__->config( name => MyApp );
201 # configure authentication
202 __PACKAGE__->config->{authentication} = {
203 user_class => 'MyApp::Model::MyDB::Customer',
207 __PACKAGE__->config->{session} = {
211 # configure email sending
212 __PACKAGE__->config->{email} = [qw/SMTP localhost/];
214 See also L<Config::General|Config::General>.
216 =head1 Skipping your VCS's directories
218 Catalyst uses Module::Pluggable to load Models, Views, and Controllers.
219 Module::Pluggable will scan through all directories and load modules
220 it finds. Sometimes you might want to skip some of these directories,
221 for example when your version control system makes a subdirectory with
222 meta-information in every version-controlled directory. While
223 Catalyst skips subversion and CVS directories already, there are other
224 source control systems. Here is the configuration you need to add
225 their directories to the list to skip.
227 You can make Catalyst skip these directories using the Catalyst config:
229 # Configure the application
232 setup_components => { except => qr/SCCS/ },
235 See the Module::Pluggable manual page for more information on B<except>
238 =head1 Users and Access Control
240 Most multiuser, and some single-user web applications require that
241 users identify themselves, and the application is often required to
242 define those roles. The recipes below describe some ways of doing
245 =head2 Authentication (logging in)
247 This is extensively covered in other documentation; see in particular
248 L<Catalyst::Plugin::Authentication> and the Authentication chapter
249 of the Tutorial at L<Catalyst::Manual::Tutorial::06_Authorization>.
251 =head2 Pass-through login (and other actions)
253 An easy way of having assorted actions that occur during the processing
254 of a request that are orthogonal to its actual purpose - logins, silent
255 commands etc. Provide actions for these, but when they're required for
256 something else fill e.g. a form variable __login and have a sub begin
259 sub begin : Private {
261 foreach my $action (qw/login docommand foo bar whatever/) {
262 if ($c->req->params->{"__${action}"}) {
263 $c->forward($action);
268 =head2 Authentication/Authorization
270 This is done in several steps:
276 Getting the user to identify themselves, by giving you some piece of
277 information known only to you and the user. Then you can assume that
278 the user is who they say they are. This is called B<credential
283 Making sure the user only accesses functions you want them to
284 access. This is done by checking the verified user's data against your
285 internal list of groups, or allowed persons for the current page.
291 The Catalyst Authentication system is made up of many interacting
292 modules, to give you the most flexibility possible.
294 =head4 Credential verifiers
296 A Credential module tables the user input, and passes it to a Store,
297 or some other system, for verification. Typically, a user object is
298 created by either this module or the Store and made accessible by a
299 C<< $c->user >> call.
303 Password - Simple username/password checking.
304 HTTPD - Checks using basic HTTP auth.
305 TypeKey - Check using the typekey system.
307 =head3 Storage backends
309 A Storage backend contains the actual data representing the users. It
310 is queried by the credential verifiers. Updating the store is not done
311 within this system; you will need to do it yourself.
315 DBIC - Storage using a database via DBIx::Class.
316 Minimal - Storage using a simple hash (for testing).
320 A User object is created by either the storage backend or the
321 credential verifier, and is filled with the retrieved user information.
325 Hash - A simple hash of keys and values.
327 =head3 ACL authorization
329 ACL stands for Access Control List. The ACL plugin allows you to
330 regulate access on a path-by-path basis, by listing which users, or
331 roles, have access to which paths.
333 =head3 Roles authorization
335 Authorization by roles is for assigning users to groups, which can
336 then be assigned to ACLs, or just checked when needed.
340 When you have chosen your modules, all you need to do is call the C<<
341 $c->authenticate >> method. If called with no parameters, it will try to find
342 suitable parameters, such as B<username> and B<password>, or you can
343 pass it these values.
345 =head3 Checking roles
347 Role checking is done by using the C<< $c->check_user_roles >> method.
348 This will check using the currently logged-in user (via C<< $c->user
349 >>). You pass it the name of a role to check, and it returns true if
350 the user is a member.
356 use namespace::autoclean;
357 extends qw/Catalyst/;
365 default_realm => 'test',
370 password_field => 'password',
371 password_type => 'self_check',
382 package MyApp::Controller::Root;
384 use namespace::autoclean;
386 BEGIN { extends 'Catalyst::Controller' }
388 __PACKAGE__->config(namespace => '');
393 if ( my $user = $c->req->params->{user}
394 and my $password = $c->req->param->{password} )
396 if ( $c->authenticate( username => $user, password => $password ) ) {
397 $c->res->body( "hello " . $c->user->name );
407 sub restricted : Local {
408 my ( $self, $c ) = @_;
410 $c->detach("unauthorized")
411 unless $c->check_user_roles( "admin" );
413 # do something restricted here
416 =head3 Using authentication in a testing environment
418 Ideally, to write tests for authentication/authorization code one would
419 first set up a test database with known data, then use
420 L<Test::WWW::Mechanize::Catalyst> to simulate a user logging
421 in. Unfortunately this can be rather awkward, which is why it's a good
422 thing that the authentication framework is so flexible.
424 Instead of using a test database, one can simply change the
425 authentication store to something a bit easier to deal with in a
426 testing environment. Additionally, this has the advantage of not
427 modifying one's database, which can be problematic if one forgets to
428 use the testing instead of production database.
430 Alternatively, if you want to authenticate real users, but not have to
431 worry about their passwords, you can use
432 L<Catalyst::Authentication::Credential::Testing> to force all users to
433 authenticate with a global password.
435 =head3 More information
437 L<Catalyst::Plugin::Authentication> has a longer explanation.
443 Authorization is the step that comes after
444 authentication. Authentication establishes that the user agent is really
445 representing the user we think it's representing, and then authorization
446 determines what this user is allowed to do.
448 =head3 Role Based Access Control
450 Under role based access control each user is allowed to perform any
451 number of roles. For example, at a zoo no one but specially trained
452 personnel can enter the moose cage (Mynd you, møøse bites kan be
453 pretty nasti!). For example:
455 package Zoo::Controller::MooseCage;
457 sub feed_moose : Local {
458 my ( $self, $c ) = @_;
460 $c->model( "Moose" )->eat( $c->req->params->{food} );
463 With this action, anyone can just come into the moose cage and feed
464 the moose, which is a very dangerous thing. We need to restrict this
465 action, so that only a qualified moose feeder can perform that action.
467 The Authorization::Roles plugin lets us perform role based access
468 control checks. Let's load it:
470 use parent qw/Catalyst/;
476 And now our action should look like this:
478 sub feed_moose : Local {
479 my ( $self, $c ) = @_;
481 if ( $c->check_roles( "moose_feeder" ) ) {
482 $c->model( "Moose" )->eat( $c->req->params->{food} );
484 $c->stash->{error} = "unauthorized";
488 This checks C<< $c->user >>, and only if the user has B<all> the roles
489 in the list, a true value is returned.
491 C<check_roles> has a sister method, C<assert_roles>, which throws an
492 exception if any roles are missing.
494 Some roles that might actually make sense in, say, a forum application:
508 each with a distinct task (system administration versus content
511 =head3 Access Control Lists
513 Checking for roles all the time can be tedious and error prone.
515 The Authorization::ACL plugin lets us declare where we'd like checks
516 to be done automatically for us.
518 For example, we may want to completely block out anyone who isn't a
519 C<moose_feeder> from the entire C<MooseCage> controller:
521 Zoo->deny_access_unless( "/moose_cage", [qw/moose_feeder/] );
523 The role list behaves in the same way as C<check_roles>. However, the
524 ACL plugin isn't limited to just interacting with the Roles plugin. We
525 can use a code reference instead. For example, to allow either moose
526 trainers or moose feeders into the moose cage, we can create a more
529 Zoo->deny_access_unless( "/moose_cage", sub {
531 $c->check_roles( "moose_trainer" ) || $c->check_roles( "moose_feeder" );
534 The more specific a role, the earlier it will be checked. Let's say
535 moose feeders are now restricted to only the C<feed_moose> action,
536 while moose trainers get access everywhere:
538 Zoo->deny_access_unless( "/moose_cage", [qw/moose_trainer/] );
539 Zoo->allow_access_if( "/moose_cage/feed_moose", [qw/moose_feeder/]);
541 When the C<feed_moose> action is accessed the second check will be
542 made. If the user is a C<moose_feeder>, then access will be
543 immediately granted. Otherwise, the next rule in line will be tested -
544 the one checking for a C<moose_trainer>. If this rule is not
545 satisfied, access will be immediately denied.
547 Rules applied to the same path will be checked in the order they were
550 Lastly, handling access denial events is done by creating an
551 C<access_denied> private action:
553 sub access_denied : Private {
554 my ( $self, $c, $action ) = @_;
557 This action works much like auto, in that it is inherited across
558 namespaces (not like object oriented code). This means that the
559 C<access_denied> action which is B<nearest> to the action which was
560 blocked will be triggered.
562 If this action does not exist, an error will be thrown, which you can
563 clean up in your C<end> private action instead.
565 Also, it's important to note that if you restrict access to "/" then
566 C<end>, C<default>, etc. will also be restricted.
568 MyApp->acl_allow_root_internals;
570 will create rules that permit access to C<end>, C<begin>, and C<auto> in the
571 root of your app (but not in any other controller).
575 Models are where application data belongs. Catalyst is extremely
576 flexible with the kind of models that it can use. The recipes here
579 =head2 Using existing DBIC (etc.) classes with Catalyst
581 Many people have existing Model classes that they would like to use
582 with Catalyst (or, conversely, they want to write Catalyst models that
583 can be used outside of Catalyst, e.g. in a cron job). It's trivial to
584 write a simple component in Catalyst that slurps in an outside Model:
586 package MyApp::Model::DB;
588 use base qw/Catalyst::Model::DBIC::Schema/;
591 schema_class => 'Some::DBIC::Schema',
592 connect_info => ['dbi:SQLite:foo.db', '', '', {AutoCommit=>1}],
597 and that's it! Now C<Some::DBIC::Schema> is part of your
598 Cat app as C<MyApp::Model::DB>.
600 =head2 DBIx::Class as a Catalyst Model
602 See L<Catalyst::Model::DBIC::Schema>.
604 =head2 Create accessors to preload static data once per server instance
606 When you have data that you want to load just once from the model at
607 startup, instead of for each request, use mk_group_accessors to
608 create accessors and tie them to resultsets in your package that
609 inherits from DBIx::Class::Schema:
612 use base qw/DBIx::Class::Schema/;
613 __PACKAGE__->register_class('RESULTSOURCEMONIKER',
614 'My::Schema::RESULTSOURCE');
615 __PACKAGE__->mk_group_accessors('simple' =>
616 qw(ACCESSORNAME1 ACCESSORNAME2 ACCESSORNAMEn));
619 my ($self, @rest) = @_;
620 $self->next::method(@rest);
621 # $self is now a live My::Schema object, complete with DB connection
623 $self->ACCESSORNAME1([ $self->resultset('RESULTSOURCEMONIKER')->all ]);
624 $self->ACCESSORNAME2([ $self->resultset('RESULTSOURCEMONIKER')->search({ COLUMN => { '<' => '30' } })->all ]);
625 $self->ACCESSORNAMEn([ $self->resultset('RESULTSOURCEMONIKER')->find(1) ]);
630 and now in the controller, you can now access any of these without a
633 $c->stash->{something} = $c->model('My::Schema')->schema->ACCESSORNAME;
638 Unlike SOAP, XMLRPC is a very simple (and elegant) web-services
639 protocol, exchanging small XML messages like these:
644 TE: deflate,gzip;q=0.3
645 Connection: TE, close
649 User-Agent: SOAP::Lite/Perl/0.60
651 Content-Type: text/xml
653 <?xml version="1.0" encoding="UTF-8"?>
655 <methodName>add</methodName>
657 <param><value><int>1</int></value></param>
658 <param><value><int>2</int></value></param>
665 Date: Tue, 20 Dec 2005 07:45:55 GMT
667 Content-Type: text/xml
671 <?xml version="1.0" encoding="us-ascii"?>
674 <param><value><int>3</int></value></param>
678 Now follow these few steps to implement the application:
680 1. Install Catalyst (5.61 or later), Catalyst::Plugin::XMLRPC (0.06 or
681 later) and SOAP::Lite (for XMLRPCsh.pl).
683 2. Create an application framework:
689 3. Add the XMLRPC plugin to MyApp.pm
691 use Catalyst qw/-Debug Static::Simple XMLRPC/;
693 4. Add an API controller
695 % ./script/myapp_create.pl controller API
697 5. Add a XMLRPC redispatch method and an add method with Remote
698 attribute to lib/MyApp/Controller/API.pm
701 my ( $self, $c ) = @_;
706 my ( $self, $c, $a, $b ) = @_;
710 The default action is the entry point for each XMLRPC request. It will
711 redispatch every request to methods with Remote attribute in the same
714 The C<add> method is not a traditional action; it has no private or
715 public path. Only the XMLRPC dispatcher knows it exists.
717 6. That's it! You have built your first web service. Let's test it with
718 XMLRPCsh.pl (part of SOAP::Lite):
720 % ./script/myapp_server.pl
722 % XMLRPCsh.pl http://127.0.0.1:3000/api
723 Usage: method[(parameters)]
725 --- XMLRPC RESULT ---
730 Your return data type is usually auto-detected, but you can easily
731 enforce a specific one.
734 my ( $self, $c, $a, $b ) = @_;
735 return RPC::XML::int->new( $a + $b );
740 Views pertain to the display of your application. As with models,
741 Catalyst is uncommonly flexible. The recipes below are just a start.
743 =head2 Catalyst::View::TT
745 One of the first things you probably want to do when starting a new
746 Catalyst application is set up your View. Catalyst doesn't care how you
747 display your data; you can choose to generate HTML, PDF files, or plain
750 Most Catalyst applications use a template system to generate their HTML,
751 and though there are several template systems available,
752 L<Template Toolkit|Template> is probably the most popular.
754 Once again, the Catalyst developers have done all the hard work, and
755 made things easy for the rest of us. Catalyst::View::TT provides the
756 interface to Template Toolkit, and provides Helpers which let us set it
757 up that much more easily.
759 =head3 Creating your View
761 Catalyst::View::TT provides two different helpers for us to use: TT and
766 Create a basic Template Toolkit View using the provided helper script:
768 script/myapp_create.pl view TT TT
770 This will create lib/MyApp/View/MyView.pm, which is going to be pretty
771 empty to start. However, it sets everything up that you need to get
772 started. You can now define which template you want and forward to your
776 my ( $self, $c ) = @_;
778 $c->stash->{template} = 'hello.tt';
780 $c->forward( $c->view('TT') );
783 In practice you wouldn't do the forwarding manually, but would
784 use L<Catalyst::Action::RenderView>.
788 Although the TT helper does create a functional, working view, you may
789 find yourself having to create the same template files and changing the
790 same options every time you create a new application. The TTSite helper
791 saves us even more time by creating the basic templates and setting some
792 common options for us.
794 Once again, you can use the helper script:
796 script/myapp_create.pl view TT TTSite
798 This time, the helper sets several options for us in the generated View.
800 __PACKAGE__->config({
801 CATALYST_VAR => 'Catalyst',
803 MyApp->path_to( 'root', 'src' ),
804 MyApp->path_to( 'root', 'lib' )
806 PRE_PROCESS => 'config/main',
807 WRAPPER => 'site/wrapper',
808 ERROR => 'error.tt2',
816 INCLUDE_PATH defines the directories that Template Toolkit should search
817 for the template files.
821 PRE_PROCESS is used to process configuration options which are common to
826 WRAPPER is a file which is processed with each template, usually used to
827 easily provide a common header and footer for every page.
831 In addition to setting these options, the TTSite helper also created the
832 template and config files for us! In the 'root' directory, you'll notice
833 two new directories: src and lib.
835 Several configuration files in root/lib/config are called by PRE_PROCESS.
837 The files in root/lib/site are the site-wide templates, called by
838 WRAPPER, and display the html framework, control the layout, and provide
839 the templates for the header and footer of your page. Using the template
840 organization provided makes it much easier to standardize pages and make
841 changes when they are (inevitably) needed.
843 The template files that you will create for your application will go
844 into root/src, and you don't need to worry about putting the the <html>
845 or <head> sections; just put in the content. The WRAPPER will the rest
846 of the page around your template for you.
851 Of course, having the template system include the header and footer for
852 you isn't all that we want our templates to do. We need to be able to
853 put data into our templates, and have it appear where and how we want
854 it, right? That's where the stash comes in.
856 In our controllers, we can add data to the stash, and then access it
857 from the template. For instance:
860 my ( $self, $c ) = @_;
862 $c->stash->{name} = 'Adam';
864 $c->stash->{template} = 'hello.tt';
866 $c->forward( $c->view('TT') );
871 <strong>Hello, [% name %]!</strong>
873 When you view this page, it will display "Hello, Adam!"
875 All of the information in your stash is available, by its name/key, in
876 your templates. And your data don't have to be plain, old, boring
877 scalars. You can pass array references and hash references, too.
882 my ( $self, $c ) = @_;
884 $c->stash->{names} = [ 'Adam', 'Dave', 'John' ];
886 $c->stash->{template} = 'hello.tt';
888 $c->forward( $c->view('TT') );
893 [% FOREACH name IN names %]
894 <strong>Hello, [% name %]!</strong><br />
897 This allowed us to loop through each item in the arrayref, and display a
898 line for each name that we have.
900 This is the most basic usage, but Template Toolkit is quite powerful,
901 and allows you to truly keep your presentation logic separate from the
902 rest of your application.
906 One of my favorite things about Catalyst is the ability to move an
907 application around without having to worry that everything is going to
908 break. One of the areas that used to be a problem was with the http
909 links in your template files. For example, suppose you have an
910 application installed at http://www.domain.com/Calendar. The links point
911 to "/Calendar", "/Calendar/2005", "/Calendar/2005/10", etc. If you move
912 the application to be at http://www.mydomain.com/Tools/Calendar, then
913 all of those links will suddenly break.
915 That's where $c->uri_for() comes in. This function will merge its
916 parameters with either the base location for the app, or its current
917 namespace. Let's take a look at a couple of examples.
919 In your template, you can use the following:
921 <a href="[% c.uri_for('/login') %]">Login Here</a>
923 Although the parameter starts with a forward slash, this is relative
924 to the application root, not the webserver root. This is important to
925 remember. So, if your application is installed at
926 http://www.domain.com/Calendar, then the link would be
927 http://www.mydomain.com/Calendar/Login. If you move your application
928 to a different domain or path, then that link will still be correct.
932 <a href="[% c.uri_for('2005','10', '24') %]">October, 24 2005</a>
934 The first parameter does NOT have a forward slash, and so it will be
935 relative to the current namespace. If the application is installed at
936 http://www.domain.com/Calendar. and if the template is called from
937 MyApp::Controller::Display, then the link would become
938 http://www.domain.com/Calendar/Display/2005/10/24.
940 If you want to link to a parent uri of your current namespace you can
941 prefix the arguments with multiple '../':
943 <a href="[% c.uri_for('../../view', stashed_object.id) %]">User view</a>
945 Once again, this allows you to move your application around without
946 having to worry about broken links. But there's something else, as
947 well. Since the links are generated by uri_for, you can use the same
948 template file by several different controllers, and each controller
949 will get the links that its supposed to. Since we believe in Don't
950 Repeat Yourself, this is particularly helpful if you have common
951 elements in your site that you want to keep in one file.
955 L<http://search.cpan.org/perldoc?Catalyst>
957 L<http://search.cpan.org/perldoc?Catalyst%3A%3AView%3A%3ATT>
959 L<http://search.cpan.org/perldoc?Template>
961 =head2 Adding RSS feeds
963 Adding RSS feeds to your Catalyst applications is simple. We'll see two
964 different approaches here, but the basic premise is that you forward to
965 the normal view action first to get the objects, then handle the output
968 =head3 Using TT templates
970 This is the approach used in Agave (L<http://dev.rawmode.org/>).
975 $c->stash->{template}='rss.tt';
978 Then you need a template. Here's the one from Agave:
980 <?xml version="1.0" encoding="UTF-8"?>
981 <rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/">
983 <title>[ [% blog.name || c.config.name || "Agave" %] ] RSS Feed</title>
984 <link>[% base %]</link>
985 <description>Recent posts</description>
986 <language>en-us</language>
988 [% WHILE (post = posts.next) %]
990 <title>[% post.title %]</title>
991 <description>[% post.formatted_teaser|html%]</description>
992 <pubDate>[% post.pub_date %]</pubDate>
993 <guid>[% post.full_uri %]</guid>
994 <link>[% post.full_uri %]</link>
995 <dc:creator>[% post.author.screenname %]</dc:creator>
1001 =head3 Using XML::Feed
1003 A more robust solution is to use L<XML::Feed>, as was done in the Catalyst
1004 Advent Calendar. Assuming we have a C<view> action that populates
1005 'entries' with some DBIx::Class iterator, the code would look something
1010 $c->forward('view'); # get the entries
1012 my $feed = XML::Feed->new('RSS');
1013 $feed->title( $c->config->{name} . ' RSS Feed' );
1014 $feed->link( $c->req->base ); # link to the site.
1015 $feed->description('Catalyst advent calendar'); Some description
1017 # Process the entries
1018 while( my $entry = $c->stash->{entries}->next ) {
1019 my $feed_entry = XML::Feed::Entry->new('RSS');
1020 $feed_entry->title($entry->title);
1021 $feed_entry->link( $c->uri_for($entry->link) );
1022 $feed_entry->issued( DateTime->from_epoch(epoch => $entry->created) );
1023 $feed->add_entry($feed_entry);
1025 $c->res->body( $feed->as_xml );
1028 A little more code in the controller, but with this approach you're
1029 pretty sure to get something that validates.
1031 Note that for both of the above approaches, you'll need to set the
1032 content type like this:
1034 $c->res->content_type('application/rss+xml');
1038 You could generalize the second variant easily by replacing 'RSS' with a
1039 variable, so you can generate Atom feeds with the same code.
1041 Now, go ahead and make RSS feeds for all your stuff. The world *needs*
1042 updates on your goldfish!
1044 =head2 Forcing the browser to download content
1046 Sometimes you need your application to send content for download. For
1047 example, you can generate a comma-separated values (CSV) file for your
1048 users to download and import into their spreadsheet program.
1050 Let's say you have an C<Orders> controller which generates a CSV file
1051 in the C<export> action (i.e., C<http://localhost:3000/orders/export>):
1053 sub export : Local Args(0) {
1054 my ( $self, $c ) = @_;
1056 # In a real application, you'd generate this from the database
1057 my $csv = "1,5.99\n2,29.99\n3,3.99\n";
1059 $c->res->content_type('text/comma-separated-values');
1060 $c->res->body($csv);
1063 Normally the browser uses the last part of the URI to generate a
1064 filename for data it cannot display. In this case your browser would
1065 likely ask you to save a file named C<export>.
1067 Luckily you can have the browser download the content with a specific
1068 filename by setting the C<Content-Disposition> header:
1070 my $filename = 'Important Orders.csv';
1071 $c->res->header('Content-Disposition', qq[attachment; filename="$filename"]);
1073 Note the use of quotes around the filename; this ensures that any
1074 spaces in the filename are handled by the browser.
1076 Put this right before calling C<< $c->res->body >> and your browser
1077 will download a file named C<Important Orders.csv> instead of
1080 You can also use this to have the browser download content which it
1081 normally displays, such as JPEG images or even HTML. Just be sure to
1082 set the appropriate content type and disposition.
1087 Controllers are the main point of communication between the web server
1088 and your application. Here we explore some aspects of how they work.
1094 A Catalyst application is driven by one or more Controller
1095 modules. There are a number of ways that Catalyst can decide which of
1096 the methods in your controller modules it should call. Controller
1097 methods are also called actions, because they determine how your
1098 catalyst application should (re-)act to any given URL. When the
1099 application is started up, catalyst looks at all your actions, and
1100 decides which URLs they map to.
1102 =head3 Type attributes
1104 Each action is a normal method in your controller, except that it has an
1105 L<attribute|attributes>
1106 attached. These can be one of several types.
1108 Assume our Controller module starts with the following package declaration:
1110 package MyApp::Controller::Buckets;
1112 and we are running our application on localhost, port 3000 (the test
1119 A Path attribute also takes an argument, this can be either a relative
1120 or an absolute path. A relative path will be relative to the
1121 controller namespace, an absolute path will represent an exact
1124 sub my_handles : Path('handles') { .. }
1128 http://localhost:3000/buckets/handles
1132 sub my_handles : Path('/handles') { .. }
1136 http://localhost:3000/handles
1138 See also: L<Catalyst::DispatchType::Path>
1142 When using a Local attribute, no parameters are needed, instead, the
1143 name of the action is matched in the URL. The namespaces created by
1144 the name of the controller package is always part of the URL.
1146 sub my_handles : Local { .. }
1150 http://localhost:3000/buckets/my_handles
1154 A Global attribute is similar to a Local attribute, except that the
1155 namespace of the controller is ignored, and matching starts at root.
1157 sub my_handles : Global { .. }
1161 http://localhost:3000/my_handles
1165 By now you should have figured that a Regex attribute is just what it
1166 sounds like. This one takes a regular expression, and matches starting
1167 from root. These differ from the rest as they can match multiple URLs.
1169 sub my_handles : Regex('^handles') { .. }
1173 http://localhost:3000/handles
1177 http://localhost:3000/handles_and_other_parts
1181 See also: L<Catalyst::DispatchType::Regex>
1185 A LocalRegex is similar to a Regex, except it only matches below the current
1186 controller namespace.
1188 sub my_handles : LocalRegex(^handles') { .. }
1192 http://localhost:3000/buckets/handles
1196 http://localhost:3000/buckets/handles_and_other_parts
1202 See L<Catalyst::DispatchType::Chained> for a description of how the chained
1203 dispatch type works.
1207 Last but not least, there is the Private attribute, which allows you
1208 to create your own internal actions, which can be forwarded to, but
1209 won't be matched as URLs.
1211 sub my_handles : Private { .. }
1213 becomes nothing at all..
1215 Catalyst also predefines some special Private actions, which you can
1216 override, these are:
1222 The default action will be called, if no other matching action is
1223 found. If you don't have one of these in your namespace, or any sub
1224 part of your namespace, you'll get an error page instead. If you want
1225 to find out where it was the user was trying to go, you can look in
1226 the request object using C<< $c->req->path >>.
1228 sub default :Path { .. }
1230 works for all unknown URLs, in this controller namespace, or every one
1231 if put directly into MyApp.pm.
1235 The index action is called when someone tries to visit the exact
1236 namespace of your controller. If index, default and matching Path
1237 actions are defined, then index will be used instead of default and
1240 sub index :Path :Args(0) { .. }
1244 http://localhost:3000/buckets
1248 The begin action is called at the beginning of every request involving
1249 this namespace directly, before other matching actions are called. It
1250 can be used to set up variables/data for this particular part of your
1251 app. A single begin action is called, its always the one most relevant
1252 to the current namespace.
1254 sub begin : Private { .. }
1258 http://localhost:3000/bucket/(anything)?
1264 Like begin, this action is always called for the namespace it is in,
1265 after every other action has finished. It is commonly used to forward
1266 processing to the View component. A single end action is called, its
1267 always the one most relevant to the current namespace.
1270 sub end : Private { .. }
1272 is called once after any actions when
1274 http://localhost:3000/bucket/(anything)?
1280 Lastly, the auto action is magic in that B<every> auto action in the
1281 chain of paths up to and including the ending namespace, will be
1282 called. (In contrast, only one of the begin/end/default actions will
1283 be called, the relevant one).
1285 package MyApp::Controller::Root;
1286 sub auto : Private { .. }
1290 sub auto : Private { .. }
1292 will both be called when visiting
1294 http://localhost:3000/bucket/(anything)?
1300 =head3 A word of warning
1302 You can put root actions in your main MyApp.pm file, but this is deprecated,
1303 please put your actions into your Root controller.
1307 A graphical flowchart of how the dispatcher works can be found on the wiki at
1308 L<http://dev.catalyst.perl.org/attachment/wiki/WikiStart/catalyst-flow.png>.
1310 =head2 DRY Controllers with Chained actions
1312 Imagine that you would like the following paths in your application:
1316 =item B<< /cd/<ID>/track/<ID> >>
1318 Displays info on a particular track.
1320 In the case of a multi-volume CD, this is the track sequence.
1322 =item B<< /cd/<ID>/volume/<ID>/track/<ID> >>
1324 Displays info on a track on a specific volume.
1328 Here is some example code, showing how to do this with chained controllers:
1330 package CD::Controller;
1331 use base qw/Catalyst::Controller/;
1333 sub root : Chained('/') PathPart('/cd') CaptureArgs(1) {
1334 my ($self, $c, $cd_id) = @_;
1335 $c->stash->{cd_id} = $cd_id;
1336 $c->stash->{cd} = $self->model('CD')->find_by_id($cd_id);
1339 sub trackinfo : Chained('track') PathPart('') Args(0) RenderView {
1340 my ($self, $c) = @_;
1343 package CD::Controller::ByTrackSeq;
1344 use base qw/CD::Controller/;
1346 sub track : Chained('root') PathPart('track') CaptureArgs(1) {
1347 my ($self, $c, $track_seq) = @_;
1348 $c->stash->{track} = $self->stash->{cd}->find_track_by_seq($track_seq);
1351 package CD::Controller::ByTrackVolNo;
1352 use base qw/CD::Controller/;
1354 sub volume : Chained('root') PathPart('volume') CaptureArgs(1) {
1355 my ($self, $c, $volume) = @_;
1356 $c->stash->{volume} = $volume;
1359 sub track : Chained('volume') PathPart('track') CaptureArgs(1) {
1360 my ($self, $c, $track_no) = @_;
1361 $c->stash->{track} = $self->stash->{cd}->find_track_by_vol_and_track_no(
1362 $c->stash->{volume}, $track_no
1366 Note that adding other actions (i.e. chain endpoints) which operate on a track
1367 is simply a matter of adding a new sub to CD::Controller - no code is duplicated,
1368 even though there are two different methods of looking up a track.
1370 This technique can be expanded as needed to fulfil your requirements - for example,
1371 if you inherit the first action of a chain from a base class, then mixing in a
1372 different base class can be used to duplicate an entire URL hierarchy at a different
1373 point within your application.
1375 =head2 Component-based Subrequests
1377 See L<Catalyst::Plugin::SubRequest>.
1381 =head3 Single file upload with Catalyst
1383 To implement uploads in Catalyst, you need to have a HTML form similar to
1386 <form action="/upload" method="post" enctype="multipart/form-data">
1387 <input type="hidden" name="form_submit" value="yes">
1388 <input type="file" name="my_file">
1389 <input type="submit" value="Send">
1392 It's very important not to forget C<enctype="multipart/form-data"> in
1395 Catalyst Controller module 'upload' action:
1397 sub upload : Global {
1398 my ($self, $c) = @_;
1400 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1402 if ( my $upload = $c->request->upload('my_file') ) {
1404 my $filename = $upload->filename;
1405 my $target = "/tmp/upload/$filename";
1407 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1408 die( "Failed to copy '$filename' to '$target': $!" );
1413 $c->stash->{template} = 'file_upload.html';
1416 =head3 Multiple file upload with Catalyst
1418 Code for uploading multiple files from one form needs a few changes:
1420 The form should have this basic structure:
1422 <form action="/upload" method="post" enctype="multipart/form-data">
1423 <input type="hidden" name="form_submit" value="yes">
1424 <input type="file" name="file1" size="50"><br>
1425 <input type="file" name="file2" size="50"><br>
1426 <input type="file" name="file3" size="50"><br>
1427 <input type="submit" value="Send">
1430 And in the controller:
1432 sub upload : Local {
1433 my ($self, $c) = @_;
1435 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1437 for my $field ( $c->req->upload ) {
1439 my $upload = $c->req->upload($field);
1440 my $filename = $upload->filename;
1441 my $target = "/tmp/upload/$filename";
1443 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1444 die( "Failed to copy '$filename' to '$target': $!" );
1449 $c->stash->{template} = 'file_upload.html';
1452 C<for my $field ($c-E<gt>req->upload)> loops automatically over all file
1453 input fields and gets input names. After that is basic file saving code,
1454 just like in single file upload.
1456 Notice: C<die>ing might not be what you want to do, when an error
1457 occurs, but it works as an example. A better idea would be to store
1458 error C<$!> in $c->stash->{error} and show a custom error template
1459 displaying this message.
1461 For more information about uploads and usable methods look at
1462 L<Catalyst::Request::Upload> and L<Catalyst::Request>.
1464 =head2 Forwarding with arguments
1466 Sometimes you want to pass along arguments when forwarding to another
1467 action. As of version 5.30, arguments can be passed in the call to
1468 C<forward>; in earlier versions, you can manually set the arguments in
1469 the Catalyst Request object:
1471 # version 5.30 and later:
1472 $c->forward('/wherever', [qw/arg1 arg2 arg3/]);
1475 $c->req->args([qw/arg1 arg2 arg3/]);
1476 $c->forward('/wherever');
1478 (See the L<Catalyst::Manual::Intro> Flow_Control section for more
1479 information on passing arguments via C<forward>.)
1481 =head2 Chained dispatch using base classes, and inner packages.
1483 package MyApp::Controller::Base;
1484 use base qw/Catalyst::Controller/;
1486 sub key1 : Chained('/')
1488 =head2 Extending RenderView (formerly DefaultEnd)
1490 The recommended approach for an C<end> action is to use
1491 L<Catalyst::Action::RenderView> (taking the place of
1492 L<Catalyst::Plugin::DefaultEnd>), which does what you usually need.
1493 However there are times when you need to add a bit to it, but don't want
1494 to write your own C<end> action.
1496 You can extend it like this:
1498 To add something to an C<end> action that is called before rendering
1499 (this is likely to be what you want), simply place it in the C<end>
1502 sub end : ActionClass('RenderView') {
1503 my ( $self, $c ) = @_;
1504 # do stuff here; the RenderView action is called afterwards
1507 To add things to an C<end> action that are called I<after> rendering,
1508 you can set it up like this:
1510 sub render : ActionClass('RenderView') { }
1513 my ( $self, $c ) = @_;
1514 $c->forward('render');
1522 The recipes below describe aspects of the deployment process,
1523 including web server engines and tips to improve application efficiency.
1525 =head2 mod_perl Deployment
1527 mod_perl is not the best solution for many applications, but we'll list some
1528 pros and cons so you can decide for yourself. The other (recommended)
1529 deployment option is FastCGI, for which see below.
1535 mod_perl is fast and your app will be loaded in memory
1536 within each Apache process.
1538 =head4 Shared memory for multiple apps
1540 If you need to run several Catalyst apps on the same server, mod_perl will
1541 share the memory for common modules.
1547 Since your application is fully loaded in memory, every Apache process will
1548 be rather large. This means a large Apache process will be tied up while
1549 serving static files, large files, or dealing with slow clients. For this
1550 reason, it is best to run a two-tiered web architecture with a lightweight
1551 frontend server passing dynamic requests to a large backend mod_perl
1556 Any changes made to the core code of your app require a full Apache restart.
1557 Catalyst does not support Apache::Reload or StatINC. This is another good
1558 reason to run a frontend web server where you can set up an
1559 C<ErrorDocument 502> page to report that your app is down for maintenance.
1561 =head4 Cannot run multiple versions of the same app
1563 It is not possible to run two different versions of the same application in
1564 the same Apache instance because the namespaces will collide.
1566 =head4 Cannot run different versions of libraries.
1568 If you have two different applications which run on the same machine,
1569 which need two different versions of a library then the only way to do
1570 this is to have per-vhost perl interpreters (with different library paths).
1571 This is entirely possible, but nullifies all the memory sharing benefits that
1572 you get from having multiple applications sharing the same interpreter.
1576 Now that we have that out of the way, let's talk about setting up mod_perl
1577 to run a Catalyst app.
1579 =head4 1. Install Catalyst::Engine::Apache
1581 You should install the latest versions of both Catalyst and
1582 Catalyst::Engine::Apache. The Apache engines were separated from the
1583 Catalyst core in version 5.50 to allow for updates to the engine without
1584 requiring a new Catalyst release.
1586 =head4 2. Install Apache with mod_perl
1588 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
1589 recommended. With Apache 2, make sure you are using the prefork MPM and not
1590 the worker MPM. The reason for this is that many Perl modules are not
1591 thread-safe and may have problems running within the threaded worker
1592 environment. Catalyst is thread-safe however, so if you know what you're
1593 doing, you may be able to run using worker.
1595 In Debian, the following commands should get you going.
1597 apt-get install apache2-mpm-prefork
1598 apt-get install libapache2-mod-perl2
1600 =head4 3. Configure your application
1602 Every Catalyst application will automagically become a mod_perl handler
1603 when run within mod_perl. This makes the configuration extremely easy.
1604 Here is a basic Apache 2 configuration.
1606 PerlSwitches -I/var/www/MyApp/lib
1611 PerlResponseHandler MyApp
1614 The most important line here is C<PerlModule MyApp>. This causes mod_perl
1615 to preload your entire application into shared memory, including all of your
1616 controller, model, and view classes and configuration. If you have -Debug
1617 mode enabled, you will see the startup output scroll by when you first
1620 For an example Apache 1.3 configuration, please see the documentation for
1621 L<Catalyst::Engine::Apache::MP13>.
1625 That's it, your app is now a full-fledged mod_perl application! Try it out
1626 by going to http://your.server.com/.
1628 =head3 Other Options
1630 =head4 Non-root location
1632 You may not always want to run your app at the root of your server or virtual
1633 host. In this case, it's a simple change to run at any non-root location
1638 PerlResponseHandler MyApp
1641 When running this way, it is best to make use of the C<uri_for> method in
1642 Catalyst for constructing correct links.
1644 =head4 Static file handling
1646 Static files can be served directly by Apache for a performance boost.
1648 DocumentRoot /var/www/MyApp/root
1650 SetHandler default-handler
1653 This will let all files within root/static be handled directly by Apache. In
1654 a two-tiered setup, the frontend server should handle static files.
1655 The configuration to do this on the frontend will vary.
1657 The same is accomplished in lighttpd with the following snippet:
1659 $HTTP["url"] !~ "^/(?:img/|static/|css/|favicon.ico$)" {
1663 "socket" => "/tmp/myapp.socket",
1664 "check-local" => "disable",
1670 Which serves everything in the img, static, css directories
1671 statically, as well as the favicon file.
1673 Note the path of the application needs to be stated explicitly in the
1674 web server configuration for both these recipes.
1676 =head2 Catalyst on shared hosting
1678 So, you want to put your Catalyst app out there for the whole world to
1679 see, but you don't want to break the bank. There is an answer - if you
1680 can get shared hosting with FastCGI and a shell, you can install your
1681 Catalyst app in a local directory on your shared host. First, run
1683 perl -MCPAN -e shell
1685 and go through the standard CPAN configuration process. Then exit out
1686 without installing anything. Next, open your .bashrc and add
1688 export PATH=$HOME/local/bin:$HOME/local/script:$PATH
1689 perlversion=`perl -v | grep 'built for' | awk '{print $4}' | sed -e 's/v//;'`
1690 export PERL5LIB=$HOME/local/share/perl/$perlversion:$HOME/local/lib/perl/$perlversion:$HOME/local/lib:$PERL5LIB
1692 and log out, then back in again (or run C<". .bashrc"> if you
1693 prefer). Finally, edit C<.cpan/CPAN/MyConfig.pm> and add
1695 'make_install_arg' => qq[SITEPREFIX=$ENV{HOME}/local],
1696 'makepl_arg' => qq[INSTALLDIRS=site install_base=$ENV{HOME}/local],
1698 Now you can install the modules you need using CPAN as normal; they
1699 will be installed into your local directory, and perl will pick them
1700 up. Finally, change directory into the root of your virtual host and
1701 symlink your application's script directory in:
1703 cd path/to/mydomain.com
1704 ln -s ~/lib/MyApp/script script
1706 And add the following lines to your .htaccess file (assuming the server
1707 is setup to handle .pl as fcgi - you may need to rename the script to
1708 myapp_fastcgi.fcgi and/or use a SetHandler directive):
1711 RewriteCond %{REQUEST_URI} !^/?script/myapp_fastcgi.pl
1712 RewriteRule ^(.*)$ script/myapp_fastcgi.pl/$1 [PT,L]
1714 Now C<http://mydomain.com/> should now Just Work. Congratulations, now
1715 you can tell your friends about your new website (or in our case, tell
1716 the client it's time to pay the invoice :) )
1718 =head2 FastCGI Deployment
1720 FastCGI is a high-performance extension to CGI. It is suitable
1721 for production environments.
1727 FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you;
1728 your app runs as multiple persistent processes ready to receive connections
1729 from the web server.
1733 When using external FastCGI servers, your application runs as a standalone
1734 application server. It may be restarted independently from the web server.
1735 This allows for a more robust environment and faster reload times when
1736 pushing new app changes. The frontend server can even be configured to
1737 display a friendly "down for maintenance" page while the application is
1740 =head4 Load-balancing
1742 You can launch your application on multiple backend servers and allow the
1743 frontend web server to load-balance between all of them. And of course, if
1744 one goes down, your app continues to run fine.
1746 =head4 Multiple versions of the same app
1748 Each FastCGI application is a separate process, so you can run different
1749 versions of the same app on a single server.
1751 =head4 Can run with threaded Apache
1753 Since your app is not running inside of Apache, the faster mpm_worker module
1754 can be used without worrying about the thread safety of your application.
1758 You may have to disable mod_deflate. If you experience page hangs with
1759 mod_fastcgi then remove deflate.load and deflate.conf from mods-enabled/
1761 =head4 More complex environment
1763 With FastCGI, there are more things to monitor and more processes running
1764 than when using mod_perl.
1768 =head4 1. Install Apache with mod_fastcgi
1770 mod_fastcgi for Apache is a third party module, and can be found at
1771 L<http://www.fastcgi.com/>. It is also packaged in many distributions,
1772 for example, libapache2-mod-fastcgi in Debian. You will also need to install
1773 the L<FCGI> module from cpan.
1775 Important Note! If you experience difficulty properly rendering pages,
1776 try disabling Apache's mod_deflate (Deflate Module), e.g. 'a2dismod deflate'.
1778 =head4 2. Configure your application
1780 # Serve static content directly
1781 DocumentRoot /var/www/MyApp/root
1782 Alias /static /var/www/MyApp/root/static
1784 FastCgiServer /var/www/MyApp/script/myapp_fastcgi.pl -processes 3
1785 Alias /myapp/ /var/www/MyApp/script/myapp_fastcgi.pl/
1787 # Or, run at the root
1788 Alias / /var/www/MyApp/script/myapp_fastcgi.pl/
1790 The above commands will launch 3 app processes and make the app available at
1793 =head3 Standalone server mode
1795 While not as easy as the previous method, running your app as an external
1796 server gives you much more flexibility.
1798 First, launch your app as a standalone server listening on a socket.
1800 script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5 -p /tmp/myapp.pid -d
1802 You can also listen on a TCP port if your web server is not on the same
1805 script/myapp_fastcgi.pl -l :8080 -n 5 -p /tmp/myapp.pid -d
1807 You will probably want to write an init script to handle starting/stopping
1808 of the app using the pid file.
1810 Now, we simply configure Apache to connect to the running server.
1812 # 502 is a Bad Gateway error, and will occur if the backend server is down
1813 # This allows us to display a friendly static page that says "down for
1815 Alias /_errors /var/www/MyApp/root/error-pages
1816 ErrorDocument 502 /_errors/502.html
1818 FastCgiExternalServer /tmp/myapp.fcgi -socket /tmp/myapp.socket
1819 Alias /myapp/ /tmp/myapp.fcgi/
1821 # Or, run at the root
1822 Alias / /tmp/myapp.fcgi/
1826 L<Catalyst::Engine::FastCGI>.
1828 =head2 Development server deployment
1830 The development server is a mini web server written in perl. If you
1831 expect a low number of hits or you don't need mod_perl/FastCGI speed,
1832 you could use the development server as the application server with a
1833 lightweight proxy web server at the front. However, consider using
1834 L<Catalyst::Engine::HTTP::Prefork> for this kind of deployment instead, since
1835 it can better handle multiple concurrent requests without forking, or can
1836 prefork a set number of servers for improved performance.
1840 As this is an application server setup, the pros are the same as
1841 FastCGI (with the exception of speed).
1846 The development server is what you create your code on, so if it works
1847 here, it should work in production!
1853 Not as fast as mod_perl or FastCGI. Needs to fork for each request
1854 that comes in - make sure static files are served by the web server to
1859 =head4 Start up the development server
1861 script/myapp_server.pl -p 8080 -k -f -pidfile=/tmp/myapp.pid
1863 You will probably want to write an init script to handle stop/starting
1864 the app using the pid file.
1866 =head4 Configuring Apache
1868 Make sure mod_proxy is enabled and add:
1870 # Serve static content directly
1871 DocumentRoot /var/www/MyApp/root
1872 Alias /static /var/www/MyApp/root/static
1880 # Need to specifically stop these paths from being passed to proxy
1882 ProxyPass /favicon.ico !
1884 ProxyPass / http://localhost:8080/
1885 ProxyPassReverse / http://localhost:8080/
1887 # This is optional if you'd like to show a custom error page
1888 # if the proxy is not available
1889 ErrorDocument 502 /static/error_pages/http502.html
1891 You can wrap the above within a VirtualHost container if you want
1892 different apps served on the same host.
1894 =head2 Quick deployment: Building PAR Packages
1896 You have an application running on your development box, but then you
1897 have to quickly move it to another one for
1898 demonstration/deployment/testing...
1900 PAR packages can save you from a lot of trouble here. They are usual Zip
1901 files that contain a blib tree; you can even include all prereqs and a
1902 perl interpreter by setting a few flags!
1904 =head3 Follow these few points to try it out!
1906 1. Install Catalyst and PAR 0.89 (or later)
1908 % perl -MCPAN -e 'install Catalyst'
1910 % perl -MCPAN -e 'install PAR'
1913 2. Create a application
1919 Recent versions of Catalyst (5.62 and up) include
1920 L<Module::Install::Catalyst>, which simplifies the process greatly. From the shell in your application directory:
1925 You can customise the PAR creation process by special "catalyst_par_*" commands
1926 available from L<Module::Install::Catalyst>. You can add these commands in your
1927 Makefile.PL just before the line containing "catalyst;"
1929 #Makefile.PL example with extra PAR options
1930 use inc::Module::Install;
1933 all_from 'lib\MyApp.pm';
1935 requires 'Catalyst::Runtime' => '5.80005';
1940 catalyst_par_core(1); # bundle perl core modules in the resulting PAR
1941 catalyst_par_multiarch(1); # build a multi-architecture PAR file
1942 catalyst_par_classes(qw/
1943 Some::Additional::Module
1945 /); # specify additional modules you want to be included into PAR
1948 install_script glob('script/*.pl');
1952 Congratulations! Your package "myapp.par" is ready, the following
1953 steps are just optional.
1955 3. Test your PAR package with "parl" (no typo)
1959 [parl] myapp[.par] [script] [arguments]
1962 parl myapp.par myapp_server.pl -r
1972 % parl myapp.par myapp_server.pl
1973 You can connect to your server at http://localhost:3000
1975 Yes, this nifty little starter application gets automatically included.
1976 You can also use "catalyst_par_script('myapp_server.pl')" to set a
1977 default script to execute.
1979 6. Want to create a binary that includes the Perl interpreter?
1981 % pp -o myapp myapp.par
1982 % ./myapp myapp_server.pl
1983 You can connect to your server at http://localhost:3000
1985 =head2 Serving static content
1987 Serving static content in Catalyst used to be somewhat tricky; the use
1988 of L<Catalyst::Plugin::Static::Simple> makes everything much easier.
1989 This plugin will automatically serve your static content during development,
1990 but allows you to easily switch to Apache (or other server) in a
1991 production environment.
1993 =head3 Introduction to Static::Simple
1995 Static::Simple is a plugin that will help to serve static content for your
1996 application. By default, it will serve most types of files, excluding some
1997 standard Template Toolkit extensions, out of your B<root> file directory. All
1998 files are served by path, so if B<images/me.jpg> is requested, then
1999 B<root/images/me.jpg> is found and served.
2003 Using the plugin is as simple as setting your use line in MyApp.pm to include:
2005 use Catalyst qw/Static::Simple/;
2007 and already files will be served.
2011 Static content is best served from a single directory within your root
2012 directory. Having many different directories such as C<root/css> and
2013 C<root/images> requires more code to manage, because you must separately
2014 identify each static directory--if you decide to add a C<root/js>
2015 directory, you'll need to change your code to account for it. In
2016 contrast, keeping all static directories as subdirectories of a main
2017 C<root/static> directory makes things much easier to manage. Here's an
2018 example of a typical root directory structure:
2022 root/controller/stuff.tt
2025 root/static/css/main.css
2026 root/static/images/logo.jpg
2027 root/static/js/code.js
2030 All static content lives under C<root/static>, with everything else being
2031 Template Toolkit files.
2037 You may of course want to change the default locations, and make
2038 Static::Simple look somewhere else, this is as easy as:
2040 MyApp->config->{static}->{include_path} = [
2041 MyApp->config->{root},
2045 When you override include_path, it will not automatically append the
2046 normal root path, so you need to add it yourself if you still want
2047 it. These will be searched in order given, and the first matching file
2050 =item Static directories
2052 If you want to force some directories to be only static, you can set
2053 them using paths relative to the root dir, or regular expressions:
2055 MyApp->config->{static}->{dirs} = [
2060 =item File extensions
2062 By default, the following extensions are not served (that is, they will
2063 be processed by Catalyst): B<tmpl, tt, tt2, html, xhtml>. This list can
2066 MyApp->config->{static}->{ignore_extensions} = [
2067 qw/tmpl tt tt2 html xhtml/
2070 =item Ignoring directories
2072 Entire directories can be ignored. If used with include_path,
2073 directories relative to the include_path dirs will also be ignored:
2075 MyApp->config->{static}->{ignore_dirs} = [ qw/tmpl css/ ];
2079 =head3 More information
2081 L<http://search.cpan.org/dist/Catalyst-Plugin-Static-Simple/>
2083 =head3 Serving manually with the Static plugin with HTTP::Daemon (myapp_server.pl)
2085 In some situations you might want to control things more directly,
2086 using L<Catalyst::Plugin::Static>.
2088 In your main application class (MyApp.pm), load the plugin:
2090 use Catalyst qw/-Debug FormValidator Static OtherPlugin/;
2092 You will also need to make sure your end method does I<not> forward
2093 static content to the view, perhaps like this:
2096 my ( $self, $c ) = @_;
2098 $c->forward( 'MyApp::View::TT' )
2099 unless ( $c->res->body || !$c->stash->{template} );
2102 This code will only forward to the view if a template has been
2103 previously defined by a controller and if there is not already data in
2104 C<$c-E<gt>res-E<gt>body>.
2106 Next, create a controller to handle requests for the /static path. Use
2107 the Helper to save time. This command will create a stub controller as
2108 C<lib/MyApp/Controller/Static.pm>.
2110 $ script/myapp_create.pl controller Static
2112 Edit the file and add the following methods:
2114 # serve all files under /static as static files
2115 sub default : Path('/static') {
2116 my ( $self, $c ) = @_;
2118 # Optional, allow the browser to cache the content
2119 $c->res->headers->header( 'Cache-Control' => 'max-age=86400' );
2121 $c->serve_static; # from Catalyst::Plugin::Static
2124 # also handle requests for /favicon.ico
2125 sub favicon : Path('/favicon.ico') {
2126 my ( $self, $c ) = @_;
2131 You can also define a different icon for the browser to use instead of
2132 favicon.ico by using this in your HTML header:
2134 <link rel="icon" href="/static/myapp.ico" type="image/x-icon" />
2136 =head3 Common problems with the Static plugin
2138 The Static plugin makes use of the C<shared-mime-info> package to
2139 automatically determine MIME types. This package is notoriously
2140 difficult to install, especially on win32 and OS X. For OS X the easiest
2141 path might be to install Fink, then use C<apt-get install
2142 shared-mime-info>. Restart the server, and everything should be fine.
2144 Make sure you are using the latest version (>= 0.16) for best
2145 results. If you are having errors serving CSS files, or if they get
2146 served as text/plain instead of text/css, you may have an outdated
2147 shared-mime-info version. You may also wish to simply use the following
2148 code in your Static controller:
2150 if ($c->req->path =~ /css$/i) {
2151 $c->serve_static( "text/css" );
2156 =head3 Serving Static Files with Apache
2158 When using Apache, you can bypass Catalyst and any Static
2159 plugins/controllers controller by intercepting requests for the
2160 C<root/static> path at the server level. All that is required is to
2161 define a DocumentRoot and add a separate Location block for your static
2162 content. Here is a complete config for this application under mod_perl
2166 use lib qw(/var/www/MyApp/lib);
2171 ServerName myapp.example.com
2172 DocumentRoot /var/www/MyApp/root
2174 SetHandler perl-script
2177 <LocationMatch "/(static|favicon.ico)">
2178 SetHandler default-handler
2182 And here's a simpler example that'll get you started:
2184 Alias /static/ "/my/static/files/"
2185 <Location "/static">
2191 Catalyst makes it easy to employ several different types of caching to
2192 speed up your applications.
2194 =head3 Cache Plugins
2196 There are three wrapper plugins around common CPAN cache modules:
2197 Cache::FastMmap, Cache::FileCache, and Cache::Memcached. These can be
2198 used to cache the result of slow operations.
2200 The Catalyst Advent Calendar uses the FileCache plugin to cache the
2201 rendered XHTML version of the source POD document. This is an ideal
2202 application for a cache because the source document changes
2203 infrequently but may be viewed many times.
2205 use Catalyst qw/Cache::FileCache/;
2210 sub render_pod : Local {
2211 my ( self, $c ) = @_;
2213 # the cache is keyed on the filename and the modification time
2214 # to check for updates to the file.
2215 my $file = $c->path_to( 'root', '2005', '11.pod' );
2216 my $mtime = ( stat $file )->mtime;
2218 my $cached_pod = $c->cache->get("$file $mtime");
2219 if ( !$cached_pod ) {
2220 $cached_pod = do_slow_pod_rendering();
2221 # cache the result for 12 hours
2222 $c->cache->set( "$file $mtime", $cached_pod, '12h' );
2224 $c->stash->{pod} = $cached_pod;
2227 We could actually cache the result forever, but using a value such as 12 hours
2228 allows old entries to be automatically expired when they are no longer needed.
2232 Another method of caching is to cache the entire HTML page. While this is
2233 traditionally handled by a front-end proxy server like Squid, the Catalyst
2234 PageCache plugin makes it trivial to cache the entire output from
2235 frequently-used or slow actions.
2237 Many sites have a busy content-filled front page that might look something
2238 like this. It probably takes a while to process, and will do the exact same
2239 thing for every single user who views the page.
2241 sub front_page : Path('/') {
2242 my ( $self, $c ) = @_;
2244 $c->forward( 'get_news_articles' );
2245 $c->forward( 'build_lots_of_boxes' );
2246 $c->forward( 'more_slow_stuff' );
2248 $c->stash->{template} = 'index.tt';
2251 We can add the PageCache plugin to speed things up.
2253 use Catalyst qw/Cache::FileCache PageCache/;
2255 sub front_page : Path ('/') {
2256 my ( $self, $c ) = @_;
2258 $c->cache_page( 300 );
2260 # same processing as above
2263 Now the entire output of the front page, from <html> to </html>, will be
2264 cached for 5 minutes. After 5 minutes, the next request will rebuild the
2265 page and it will be re-cached.
2267 Note that the page cache is keyed on the page URI plus all parameters, so
2268 requests for / and /?foo=bar will result in different cache items. Also,
2269 only GET requests will be cached by the plugin.
2271 You can even get that front-end Squid proxy to help out by enabling HTTP
2272 headers for the cached page.
2274 MyApp->config->{page_cache}->{set_http_headers} = 1;
2276 This would now set the following headers so proxies and browsers may cache
2277 the content themselves.
2279 Cache-Control: max-age=($expire_time - time)
2280 Expires: $expire_time
2281 Last-Modified: $cache_created_time
2283 =head3 Template Caching
2285 Template Toolkit provides support for caching compiled versions of your
2286 templates. To enable this in Catalyst, use the following configuration.
2287 TT will cache compiled templates keyed on the file mtime, so changes will
2288 still be automatically detected.
2290 package MyApp::View::TT;
2294 use base 'Catalyst::View::TT';
2296 __PACKAGE__->config(
2297 COMPILE_DIR => '/tmp/template_cache',
2304 See the documentation for each cache plugin for more details and other
2305 available configuration options.
2307 L<Catalyst::Plugin::Cache::FastMmap>
2308 L<Catalyst::Plugin::Cache::FileCache>
2309 L<Catalyst::Plugin::Cache::Memcached>
2310 L<Catalyst::Plugin::PageCache>
2311 L<http://search.cpan.org/dist/Template-Toolkit/lib/Template/Manual/Config.pod#Caching_and_Compiling_Options>
2315 Testing is an integral part of the web application development
2316 process. Tests make multi developer teams easier to coordinate, and
2317 they help ensure that there are no nasty surprises after upgrades or
2322 Catalyst provides a convenient way of testing your application during
2323 development and before deployment in a real environment.
2325 C<Catalyst::Test> makes it possible to run the same tests both locally
2326 (without an external daemon) and against a remote server via HTTP.
2330 Let's examine a skeleton application's C<t/> directory:
2332 mundus:~/MyApp chansen$ ls -l t/
2334 -rw-r--r-- 1 chansen chansen 95 18 Dec 20:50 01app.t
2335 -rw-r--r-- 1 chansen chansen 190 18 Dec 20:50 02pod.t
2336 -rw-r--r-- 1 chansen chansen 213 18 Dec 20:50 03podcoverage.t
2342 Verifies that the application loads, compiles, and returns a successful
2347 Verifies that all POD is free from errors. Only executed if the C<TEST_POD>
2348 environment variable is true.
2350 =item C<03podcoverage.t>
2352 Verifies that all methods/functions have POD coverage. Only executed if the
2353 C<TEST_POD> environment variable is true.
2357 =head3 Creating tests
2359 mundus:~/MyApp chansen$ cat t/01app.t | perl -ne 'printf( "%2d %s", $., $_ )'
2360 1 use Test::More tests => 2;
2361 2 BEGIN { use_ok( Catalyst::Test, 'MyApp' ) }
2363 4 ok( request('/')->is_success );
2365 The first line declares how many tests we are going to run, in this case
2366 two. The second line tests and loads our application in test mode. The
2367 fourth line verifies that our application returns a successful response.
2369 C<Catalyst::Test> exports two functions, C<request> and C<get>. Each can
2370 take three different arguments:
2374 =item A string which is a relative or absolute URI.
2376 request('/my/path');
2377 request('http://www.host.com/my/path');
2379 =item An instance of C<URI>.
2381 request( URI->new('http://www.host.com/my/path') );
2383 =item An instance of C<HTTP::Request>.
2385 request( HTTP::Request->new( GET => 'http://www.host.com/my/path') );
2389 C<request> returns an instance of C<HTTP::Response> and C<get> returns the
2390 content (body) of the response.
2392 =head3 Running tests locally
2394 mundus:~/MyApp chansen$ CATALYST_DEBUG=0 TEST_POD=1 prove --lib lib/ t/
2395 t/01app............ok
2396 t/02pod............ok
2397 t/03podcoverage....ok
2398 All tests successful.
2399 Files=3, Tests=4, 2 wallclock secs ( 1.60 cusr + 0.36 csys = 1.96 CPU)
2401 C<CATALYST_DEBUG=0> ensures that debugging is off; if it's enabled you
2402 will see debug logs between tests.
2404 C<TEST_POD=1> enables POD checking and coverage.
2406 C<prove> A command-line tool that makes it easy to run tests. You can
2407 find out more about it from the links below.
2409 =head3 Running tests remotely
2411 mundus:~/MyApp chansen$ CATALYST_SERVER=http://localhost:3000/ prove --lib lib/ t/01app.t
2413 All tests successful.
2414 Files=1, Tests=2, 0 wallclock secs ( 0.40 cusr + 0.01 csys = 0.41 CPU)
2416 C<CATALYST_SERVER=http://localhost:3000/> is the absolute deployment URI of
2417 your application. In C<CGI> or C<FastCGI> it should be the host and path
2420 =head3 C<Test::WWW::Mechanize> and Catalyst
2422 Be sure to check out C<Test::WWW::Mechanize::Catalyst>. It makes it easy to
2423 test HTML, forms and links. A short example of usage:
2425 use Test::More tests => 6;
2426 BEGIN { use_ok( Test::WWW::Mechanize::Catalyst, 'MyApp' ) }
2428 my $mech = Test::WWW::Mechanize::Catalyst->new;
2429 $mech->get_ok("http://localhost/", 'Got index page');
2430 $mech->title_like( qr/^MyApp on Catalyst/, 'Got right index title' );
2431 ok( $mech->find_link( text_regex => qr/^Wiki/i ), 'Found link to Wiki' );
2432 ok( $mech->find_link( text_regex => qr/^Mailing-List/i ), 'Found link to Mailing-List' );
2433 ok( $mech->find_link( text_regex => qr/^IRC channel/i ), 'Found link to IRC channel' );
2435 =head3 Further Reading
2439 =item Catalyst::Test
2443 =item Test::WWW::Mechanize::Catalyst
2445 L<http://search.cpan.org/dist/Test-WWW-Mechanize-Catalyst/lib/Test/WWW/Mechanize/Catalyst.pm>
2447 =item Test::WWW::Mechanize
2449 L<http://search.cpan.org/dist/Test-WWW-Mechanize/Mechanize.pm>
2451 =item WWW::Mechanize
2453 L<http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm>
2455 =item LWP::UserAgent
2457 L<http://search.cpan.org/dist/libwww-perl/lib/LWP/UserAgent.pm>
2461 L<http://search.cpan.org/dist/libwww-perl/lib/HTML/Form.pm>
2465 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Message.pm>
2469 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request.pm>
2471 =item HTTP::Request::Common
2473 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request/Common.pm>
2475 =item HTTP::Response
2477 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Response.pm>
2481 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Status.pm>
2485 L<http://search.cpan.org/dist/URI/URI.pm>
2489 L<http://search.cpan.org/dist/Test-Simple/lib/Test/More.pm>
2493 L<http://search.cpan.org/dist/Test-Pod/Pod.pm>
2495 =item Test::Pod::Coverage
2497 L<http://search.cpan.org/dist/Test-Pod-Coverage/Coverage.pm>
2499 =item prove (Test::Harness)
2501 L<http://search.cpan.org/dist/Test-Harness/bin/prove>
2505 =head3 More Information
2507 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::Roles>
2508 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::ACL>
2512 Catalyst Contributors, see Catalyst.pm
2516 This library is free software. You can redistribute it and/or modify it under
2517 the same terms as Perl itself.