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 Session::Store::FastMmap
118 Session::State::Cookie
122 ## Write data into the session
124 sub add_item : Local {
125 my ( $self, $c ) = @_;
127 my $item_id = $c->req->param("item");
129 push @{ $c->session->{items} }, $item_id;
133 ## A page later we retrieve the data from the session:
135 sub get_items : Local {
136 my ( $self, $c ) = @_;
138 $c->stash->{items_to_display} = $c->session->{items};
143 =head3 More information
145 L<http://search.cpan.org/dist/Catalyst-Plugin-Session>
147 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-Cookie>
149 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-URI>
151 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-FastMmap>
153 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-File>
155 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-DBI>
157 =head2 Configure your application
159 You configure your application with the C<config> method in your
160 application class. This can be hard-coded, or brought in from a
161 separate configuration file.
165 YAML is a method for creating flexible and readable configuration
166 files. It's a great way to keep your Catalyst application
167 configuration in one easy-to-understand location.
169 In your application class (e.g. C<lib/MyApp.pm>):
173 __PACKAGE__->config( YAML::LoadFile(__PACKAGE__->config->{'home'} . '/myapp.yml') );
176 Now create C<myapp.yml> in your application home:
179 # DO NOT USE TABS FOR INDENTATION OR label/value SEPARATION!!!
182 # session; perldoc Catalyst::Plugin::Session::FastMmap
186 storage: '/tmp/myapp.session'
188 # emails; perldoc Catalyst::Plugin::Email
189 # 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/];
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);
266 =head2 Role-based Authorization
268 For more advanced access control, you may want to consider using role-based
269 authorization. This means you can assign different roles to each user, e.g.
270 "user", "admin", etc.
272 The C<login> and C<logout> methods and view template are exactly the same as
273 in the previous example.
275 The L<Catalyst::Plugin::Authorization::Roles> plugin is required when
280 Authentication::Credential::Password
281 Authentication::Store::Htpasswd
285 Roles are implemented automatically when using
286 L<Catalyst::Authentication::Store::Htpasswd>:
288 # no additional role configuration required
289 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
291 Or can be set up manually when using L<Catalyst::Authentication::Store::DBIC>:
293 # Authorization using a many-to-many role relationship
294 __PACKAGE__->config->{authorization}{dbic} = {
295 'role_class' => 'My::Model::DBIC::Role',
296 'role_field' => 'name',
297 'user_role_user_field' => 'user',
299 # DBIx::Class only (omit if using Class::DBI)
300 'role_rel' => 'user_role',
302 # Class::DBI only, (omit if using DBIx::Class)
303 'user_role_class' => 'My::Model::CDBI::UserRole'
304 'user_role_role_field' => 'role',
307 To restrict access to any action, you can use the C<check_user_roles> method:
309 sub restricted : Local {
310 my ( $self, $c ) = @_;
312 $c->detach("unauthorized")
313 unless $c->check_user_roles( "admin" );
315 # do something restricted here
318 You can also use the C<assert_user_roles> method. This just gives an
319 error if the current user does not have one of the required roles:
321 sub also_restricted : Global {
322 my ( $self, $c ) = @_;
323 $c->assert_user_roles( qw/ user admin / );
326 =head2 Authentication/Authorization
328 This is done in several steps:
334 Getting the user to identify themselves, by giving you some piece of
335 information known only to you and the user. Then you can assume that
336 the user is who they say they are. This is called B<credential
341 Making sure the user only accesses functions you want them to
342 access. This is done by checking the verified users data against your
343 internal list of groups, or allowed persons for the current page.
349 The Catalyst Authentication system is made up of many interacting
350 modules, to give you the most flexibility possible.
352 =head4 Credential verifiers
354 A Credential module tables the user input, and passes it to a Store,
355 or some other system, for verification. Typically, a user object is
356 created by either this module or the Store and made accessible by a
357 C<< $c->user >> call.
361 Password - Simple username/password checking.
362 HTTPD - Checks using basic HTTP auth.
363 TypeKey - Check using the typekey system.
365 =head3 Storage backends
367 A Storage backend contains the actual data representing the users. It
368 is queried by the credential verifiers. Updating the store is not done
369 within this system, you will need to do it yourself.
373 DBIC - Storage using a database.
374 Minimal - Storage using a simple hash (for testing).
378 A User object is created by either the storage backend or the
379 credential verifier, and filled with the retrieved user information.
383 Hash - A simple hash of keys and values.
385 =head3 ACL authorization
387 ACL stands for Access Control List. The ACL plugin allows you to
388 regulate access on a path by path basis, by listing which users, or
389 roles, have access to which paths.
391 =head3 Roles authorization
393 Authorization by roles is for assigning users to groups, which can
394 then be assigned to ACLs, or just checked when needed.
398 When you have chosen your modules, all you need to do is call the C<<
399 $c->login >> method. If called with no parameters, it will try to find
400 suitable parameters, such as B<username> and B<password>, or you can
401 pass it these values.
403 =head3 Checking roles
405 Role checking is done by using the C<< $c->check_user_roles >> method,
406 this will check using the currently logged in user (via C<< $c->user
407 >>). You pass it the name of a role to check, and it returns true if
408 the user is a member.
412 use Catalyst qw/Authentication
413 Authentication::Credential::Password
414 Authentication::Store::Htpasswd
415 Authorization::Roles/;
417 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
422 if ( my $user = $c->req->param("user")
423 and my $password = $c->req->param("password") )
425 if ( $c->login( $user, $password ) ) {
426 $c->res->body( "hello " . $c->user->name );
436 sub restricted : Local {
437 my ( $self, $c ) = @_;
439 $c->detach("unauthorized")
440 unless $c->check_user_roles( "admin" );
442 # do something restricted here
445 =head3 Using authentication in a testing environment
447 Ideally, to write tests for authentication/authorization code one
448 would first set up a test database with known data, then use
449 L<Test::WWW::Mechanize::Catalyst> to simulate a user logging
450 in. Unfortunately the former can be rather awkward, which is why it's
451 a good thing that the authentication framework is so flexible.
453 Instead of using a test database, one can simply change the
454 authentication store to something a bit easier to deal with in a
455 testing environment. Additionally, this has the advantage of not
456 modifying one's database, which can be problematic if one forgets to
457 use the testing instead of production database.
461 use Catalyst::Plugin::Authentication::Store::Minimal::Backend;
463 # Sets up the user `test_user' with password `test_pass'
464 MyApp->default_auth_store(
465 Catalyst::Plugin::Authentication::Store::Minimal::Backend->new({
466 test_user => { password => 'test_pass' },
470 Now, your test code can call C<$c->login('test_user', 'test_pass')> and
471 successfully login, without messing with the database at all.
473 =head3 More information
475 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authentication> has a longer explanation.
481 Authorization is the step that comes after
482 authentication. Authentication establishes that the user agent is
483 really representing the user we think it's representing, and then
484 authorization determines what this user is allowed to do.
486 =head3 Role Based Access Control
488 Under role based access control each user is allowed to perform any
489 number of roles. For example, at a zoo no one but specially trained
490 personnel can enter the moose cage (Mynd you, møøse bites kan be
491 pretty nasti!). For example:
493 package Zoo::Controller::MooseCage;
495 sub feed_moose : Local {
496 my ( $self, $c ) = @_;
498 $c->model( "Moose" )->eat( $c->req->param("food") );
501 With this action, anyone can just come into the moose cage and feed
502 the moose, which is a very dangerous thing. We need to restrict this
503 action, so that only a qualified moose feeder can perform that action.
505 The Authorization::Roles plugin let's us perform role based access
506 control checks. Let's load it:
509 Authentication # yadda yadda
513 And now our action should look like this:
515 sub feed_moose : Local {
516 my ( $self, $c ) = @_;
518 if ( $c->check_roles( "moose_feeder" ) ) {
519 $c->model( "Moose" )->eat( $c->req->param("food") );
521 $c->stash->{error} = "unauthorized";
525 This checks C<< $c->user >>, and only if the user has B<all> the roles
526 in the list, a true value is returned.
528 C<check_roles> has a sister method, C<assert_roles>, which throws an
529 exception if any roles are missing.
531 Some roles that might actually make sense in, say, a forum application:
545 each with a distinct task (system administration versus content
548 =head3 Access Control Lists
550 Checking for roles all the time can be tedious and error prone.
552 The Authorization::ACL plugin let's us declare where we'd like checks
553 to be done automatically for us.
555 For example, we may want to completely block out anyone who isn't a
556 C<moose_feeder> from the entire C<MooseCage> controller:
558 Zoo->deny_access_unless( "/moose_cage", [qw/moose_feeder/] );
560 The role list behaves in the same way as C<check_roles>. However, the
561 ACL plugin isn't limited to just interacting with the Roles plugin. We
562 can use a code reference instead. For example, to allow either moose
563 trainers or moose feeders into the moose cage, we can create a more
566 Zoo->deny_access_unless( "/moose_cage", sub {
568 $c->check_roles( "moose_trainer" ) || $c->check_roles( "moose_feeder" );
571 The more specific a role, the earlier it will be checked. Let's say
572 moose feeders are now restricted to only the C<feed_moose> action,
573 while moose trainers get access everywhere:
575 Zoo->deny_access_unless( "/moose_cage", [qw/moose_trainer/] );
576 Zoo->allow_access_if( "/moose_cage/feed_moose", [qw/moose_feeder/]);
578 When the C<feed_moose> action is accessed the second check will be
579 made. If the user is a C<moose_feeder>, then access will be
580 immediately granted. Otherwise, the next rule in line will be tested -
581 the one checking for a C<moose_trainer>. If this rule is not
582 satisfied, access will be immediately denied.
584 Rules applied to the same path will be checked in the order they were
587 Lastly, handling access denial events is done by creating an
588 C<access_denied> private action:
590 sub access_denied : Private {
591 my ( $self, $c, $action ) = @_;
594 This action works much like auto, in that it is inherited across
595 namespaces (not like object oriented code). This means that the
596 C<access_denied> action which is B<nearest> to the action which was
597 blocked will be triggered.
599 If this action does not exist, an error will be thrown, which you can
600 clean up in your C<end> private action instead.
602 Also, it's important to note that if you restrict access to "/" then
603 C<end>, C<default>, etc will also be restricted.
605 MyApp->acl_allow_root_internals;
607 will create rules that permit access to C<end>, C<begin>, and C<auto> in the
608 root of your app (but not in any other controller).
612 Models are where application data belongs. Catalyst is exteremely
613 flexible with the kind of models that it can use. The recipes here
616 =head2 Using existing DBIC (etc.) classes with Catalyst
618 Many people have existing Model classes that they would like to use
619 with Catalyst (or, conversely, they want to write Catalyst models that
620 can be used outside of Catalyst, e.g. in a cron job). It's trivial to
621 write a simple component in Catalyst that slurps in an outside Model:
623 package MyApp::Model::DB;
624 use base qw/Catalyst::Model::DBIC::Schema/;
626 schema_class => 'Some::DBIC::Schema',
627 connect_info => ['dbi:SQLite:foo.db', '', '', {AutoCommit=>1}];
631 and that's it! Now C<Some::DBIC::Schema> is part of your
632 Cat app as C<MyApp::Model::DB>.
634 =head2 DBIx::Class as a Catalyst Model
636 See L<Catalyst::Model::DBIC::Schema>.
638 =head2 Create accessors to preload static data once per server instance
640 When you have data that you want to load just once from the model at
641 server load instead of for each request, use mk_group_accessors to
642 create accessors and tie them to resultsets in your package that
643 inherits from DBIx::Class::Schema
646 use base qw/DBIx::Class::Schema/;
647 __PACKAGE__->register_class('RESULTSOURCEMONIKER',
648 'My::Schema::RESULTSOURCE');
649 __PACKAGE__->mk_group_accessors('simple' =>
650 qw(ACCESSORNAME1 ACCESSORNAME2 ACCESSORNAMEn));
653 my ($self, @rest) = @_;
654 $self->next::method(@rest);
655 # $self is now a live My::Schema object, complete with DB connection
657 $self->ACCESSORNAME1([ $self->resultset('RESULTSOURCEMONIKER')->all ]);
658 $self->ACCESSORNAME2([ $self->resultset('RESULTSOURCEMONIKER')->search({ COLUMN => { '<' => '30' } })->all ]);
659 $self->ACCESSORNAMEn([ $self->resultset('RESULTSOURCEMONIKER')->find(1) ]);
664 and now in the controller, you can now access any of these without a
667 $c->stash->{something} = $c->model('My::Schema')->schema->ACCESSORNAMEn;
672 Unlike SOAP, XMLRPC is a very simple (and imo elegant) web-services
673 protocol, exchanging small XML messages like these:
678 TE: deflate,gzip;q=0.3
679 Connection: TE, close
683 User-Agent: SOAP::Lite/Perl/0.60
685 Content-Type: text/xml
687 <?xml version="1.0" encoding="UTF-8"?>
689 <methodName>add</methodName>
691 <param><value><int>1</int></value></param>
692 <param><value><int>2</int></value></param>
699 Date: Tue, 20 Dec 2005 07:45:55 GMT
701 Content-Type: text/xml
705 <?xml version="1.0" encoding="us-ascii"?>
708 <param><value><int>3</int></value></param>
712 Now follow these few steps to implement the application:
714 1. Install Catalyst (5.61 or later), Catalyst::Plugin::XMLRPC (0.06 or
715 later) and SOAP::Lite (for XMLRPCsh.pl).
717 2. Create an application framework:
723 3. Add the XMLRPC plugin to MyApp.pm
725 use Catalyst qw/-Debug Static::Simple XMLRPC/;
727 4. Add an API controller
729 % ./script/myapp_create.pl controller API
731 5. Add a XMLRPC redispatch method and an add method with Remote
732 attribute to lib/MyApp/Controller/API.pm
734 sub default : Private {
735 my ( $self, $c ) = @_;
740 my ( $self, $c, $a, $b ) = @_;
744 The default action is the entry point for each XMLRPC request. It will
745 redispatch every request to methods with Remote attribute in the same
748 The C<add> method is not a traditional action; it has no private or
749 public path. Only the XMLRPC dispatcher knows it exists.
751 6. That's it! You have built your first web service. Let's test it with
752 XMLRPCsh.pl (part of SOAP::Lite):
754 % ./script/myapp_server.pl
756 % XMLRPCsh.pl http://127.0.0.1:3000/api
757 Usage: method[(parameters)]
759 --- XMLRPC RESULT ---
764 Your return data type is usually auto-detected, but you can easily
765 enforce a specific one.
768 my ( $self, $c, $a, $b ) = @_;
769 return RPC::XML::int->new( $a + $b );
776 Views pertain to the display of your application. As with models,
777 catalyst is uncommonly flexible. The recipes below are just a start.
779 =head2 Catalyst::View::TT
781 One of the first things you probably want to do when starting a new
782 Catalyst application is set up your View. Catalyst doesn't care how you
783 display your data; you can choose to generate HTML, PDF files, or plain
786 Most Catalyst applications use a template system to generate their HTML,
787 and though there are several template systems available, Template
788 Toolkit is probably the most popular.
790 Once again, the Catalyst developers have done all the hard work, and
791 made things easy for the rest of us. Catalyst::View::TT provides the
792 interface to Template Toolkit, and provides Helpers which let us set it
793 up that much more easily.
795 =head3 Creating your View
797 Catalyst::View::TT provides two different helpers for us to use: TT and
802 Create a basic Template Toolkit View using the provided helper script:
804 script/myapp_create.pl view TT TT
806 This will create lib/MyApp/View/MyView.pm, which is going to be pretty
807 empty to start. However, it sets everything up that you need to get
808 started. You can now define which template you want and forward to your
812 my ( $self, $c ) = @_;
814 $c->stash->{template} = 'hello.tt';
816 $c->forward( $c->view('TT') );
819 In practice you wouldn't do the forwarding manually, but would
820 use L<Catalyst::Action::RenderView>.
824 Although the TT helper does create a functional, working view, you may
825 find yourself having to create the same template files and changing the
826 same options every time you create a new application. The TTSite helper
827 saves us even more time by creating the basic templates and setting some
828 common options for us.
830 Once again, you can use the helper script:
832 script/myapp_create.pl view TT TTSite
834 This time, the helper sets several options for us in the generated View.
836 __PACKAGE__->config({
837 CATALYST_VAR => 'Catalyst',
839 MyApp->path_to( 'root', 'src' ),
840 MyApp->path_to( 'root', 'lib' )
842 PRE_PROCESS => 'config/main',
843 WRAPPER => 'site/wrapper',
844 ERROR => 'error.tt2',
852 INCLUDE_PATH defines the directories that Template Toolkit should search
853 for the template files.
857 PRE_PROCESS is used to process configuration options which are common to
862 WRAPPER is a file which is processed with each template, usually used to
863 easily provide a common header and footer for every page.
867 In addition to setting these options, the TTSite helper also created the
868 template and config files for us! In the 'root' directory, you'll notice
869 two new directories: src and lib.
871 Several configuration files in root/lib/config are called by PRE_PROCESS.
873 The files in root/lib/site are the site-wide templates, called by
874 WRAPPER, and display the html framework, control the layout, and provide
875 the templates for the header and footer of your page. Using the template
876 organization provided makes it much easier to standardize pages and make
877 changes when they are (inevitably) needed.
879 The template files that you will create for your application will go
880 into root/src, and you don't need to worry about putting the the <html>
881 or <head> sections; just put in the content. The WRAPPER will the rest
882 of the page around your template for you.
887 Of course, having the template system include the header and footer for
888 you isn't all that we want our templates to do. We need to be able to
889 put data into our templates, and have it appear where and how we want
890 it, right? That's where the stash comes in.
892 In our controllers, we can add data to the stash, and then access it
893 from the template. For instance:
896 my ( $self, $c ) = @_;
898 $c->stash->{name} = 'Adam';
900 $c->stash->{template} = 'hello.tt';
902 $c->forward( $c->view('TT') );
907 <strong>Hello, [% name %]!</strong>
909 When you view this page, it will display "Hello, Adam!"
911 All of the information in your stash is available, by its name/key, in
912 your templates. And your data don't have to be plain, old, boring
913 scalars. You can pass array references and hash references, too.
918 my ( $self, $c ) = @_;
920 $c->stash->{names} = [ 'Adam', 'Dave', 'John' ];
922 $c->stash->{template} = 'hello.tt';
924 $c->forward( $c->view('TT') );
929 [% FOREACH name IN names %]
930 <strong>Hello, [% name %]!</strong><br />
933 This allowed us to loop through each item in the arrayref, and display a
934 line for each name that we have.
936 This is the most basic usage, but Template Toolkit is quite powerful,
937 and allows you to truly keep your presentation logic separate from the
938 rest of your application.
942 One of my favorite things about Catalyst is the ability to move an
943 application around without having to worry that everything is going to
944 break. One of the areas that used to be a problem was with the http
945 links in your template files. For example, suppose you have an
946 application installed at http://www.domain.com/Calendar. The links point
947 to "/Calendar", "/Calendar/2005", "/Calendar/2005/10", etc. If you move
948 the application to be at http://www.mydomain.com/Tools/Calendar, then
949 all of those links will suddenly break.
951 That's where $c->uri_for() comes in. This function will merge its
952 parameters with either the base location for the app, or its current
953 namespace. Let's take a look at a couple of examples.
955 In your template, you can use the following:
957 <a href="[% c.uri_for('/login') %]">Login Here</a>
959 Although the parameter starts with a forward slash, this is relative
960 to the application root, not the webserver root. This is important to
961 remember. So, if your application is installed at
962 http://www.domain.com/Calendar, then the link would be
963 http://www.mydomain.com/Calendar/Login. If you move your application
964 to a different domain or path, then that link will still be correct.
968 <a href="[% c.uri_for('2005','10', '24') %]">October, 24 2005</a>
970 The first parameter does NOT have a forward slash, and so it will be
971 relative to the current namespace. If the application is installed at
972 http://www.domain.com/Calendar. and if the template is called from
973 MyApp::Controller::Display, then the link would become
974 http://www.domain.com/Calendar/Display/2005/10/24.
976 If you want to link to a parent uri of your current namespace you can
977 prefix the arguments with multiple '../':
979 <a href="[% c.uri_for('../../view', stashed_object.id) %]">User view</a>
981 Once again, this allows you to move your application around without
982 having to worry about broken links. But there's something else, as
983 well. Since the links are generated by uri_for, you can use the same
984 template file by several different controllers, and each controller
985 will get the links that its supposed to. Since we believe in Don't
986 Repeat Yourself, this is particularly helpful if you have common
987 elements in your site that you want to keep in one file.
991 L<http://search.cpan.org/perldoc?Catalyst>
993 L<http://search.cpan.org/perldoc?Catalyst%3A%3AView%3A%3ATT>
995 L<http://search.cpan.org/perldoc?Template>
997 =head2 Adding RSS feeds
999 Adding RSS feeds to your Catalyst applications is simple. We'll see two
1000 different aproaches here, but the basic premise is that you forward to
1001 the normal view action first to get the objects, then handle the output
1004 =head3 Using TT templates
1006 This is the aproach used in Agave (L<http://dev.rawmode.org/>).
1010 $c->forward('view');
1011 $c->stash->{template}='rss.tt';
1014 Then you need a template. Here's the one from Agave:
1016 <?xml version="1.0" encoding="UTF-8"?>
1017 <rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/">
1019 <title>[ [% blog.name || c.config.name || "Agave" %] ] RSS Feed</title>
1020 <link>[% base %]</link>
1021 <description>Recent posts</description>
1022 <language>en-us</language>
1024 [% WHILE (post = posts.next) %]
1026 <title>[% post.title %]</title>
1027 <description>[% post.formatted_teaser|html%]</description>
1028 <pubDate>[% post.pub_date %]</pubDate>
1029 <guid>[% post.full_uri %]</guid>
1030 <link>[% post.full_uri %]</link>
1031 <dc:creator>[% post.author.screenname %]</dc:creator>
1037 =head3 Using XML::Feed
1039 A more robust solution is to use XML::Feed, as was done in the Catalyst
1040 Advent Calendar. Assuming we have a C<view> action that populates
1041 'entries' with some DBIx::Class iterator, the code would look something
1046 $c->forward('view'); # get the entries
1048 my $feed = XML::Feed->new('RSS');
1049 $feed->title( $c->config->{name} . ' RSS Feed' );
1050 $feed->link( $c->req->base ); # link to the site.
1051 $feed->description('Catalyst advent calendar'); Some description
1053 # Process the entries
1054 while( my $entry = $c->stash->{entries}->next ) {
1055 my $feed_entry = XML::Feed::Entry->new('RSS');
1056 $feed_entry->title($entry->title);
1057 $feed_entry->link( $c->uri_for($entry->link) );
1058 $feed_entry->issued( DateTime->from_epoch(epoch => $entry->created) );
1059 $feed->add_entry($feed_entry);
1061 $c->res->body( $feed->as_xml );
1064 A little more code in the controller, but with this approach you're
1065 pretty sure to get something that validates.
1067 Note that for both of the above aproaches, you'll need to set the
1068 content type like this:
1070 $c->res->content_type('application/rss+xml');
1074 You could generalize the second variant easily by replacing 'RSS' with a
1075 variable, so you can generate Atom feeds with the same code.
1077 Now, go ahead and make RSS feeds for all your stuff. The world *needs*
1078 updates on your goldfish!
1080 =head2 Forcing the browser to download content
1082 Sometimes you need your application to send content for download. For
1083 example, you can generate a comma-separated values (CSV) file for your
1084 users to download and import into their spreadsheet program.
1086 Let's say you have an C<Orders> controller which generates a CSV file
1087 in the C<export> action (i.e., C<http://localhost:3000/orders/export>):
1089 sub export : Local Args(0) {
1090 my ( $self, $c ) = @_;
1092 # In a real application, you'd generate this from the database
1093 my $csv = "1,5.99\n2,29.99\n3,3.99\n";
1095 $c->res->content_type('text/comma-separated-values');
1096 $c->res->body($csv);
1099 Normally the browser uses the last part of the URI to generate a
1100 filename for data it cannot display. In this case your browser would
1101 likely ask you to save a file named C<export>.
1103 Luckily you can have the browser download the content with a specific
1104 filename by setting the C<Content-Disposition> header:
1106 my $filename = 'Important Orders.csv';
1107 $c->res->header('Content-Disposition', qq[attachment; filename="$filename"]);
1109 Note the use of quotes around the filename; this ensures that any
1110 spaces in the filename are handled by the browser.
1112 Put this right before calling C<< $c->res->body >> and your browser
1113 will download a file named C<Important Orders.csv> instead of
1116 You can also use this to have the browser download content which it
1117 normally displays, such as JPEG images or even HTML. Just be sure to
1118 set the appropriate content type and disposition.
1123 Controllers are the main point of communication between the web server
1124 and your application. Here we explore some aspects of how they work.
1126 =head2 Extending RenderView (formerly DefaultEnd)
1128 The recommended approach for an C<end> action is to use
1129 L<Catalyst::Action::RenderView> (taking the place of
1130 L<Catalyst::Plugin::DefaultEnd>), which does what you usually need.
1131 However there are times when you need to add a bit to it, but don't want
1132 to write your own C<end> action.
1134 You can extend it like this:
1136 To add something to an C<end> action that is called before rendering
1137 (this is likely to be what you want), simply place it in the C<end>
1140 sub end : ActionClass('RenderView') {
1141 my ( $self, $c ) = @_;
1142 # do stuff here; the RenderView action is called afterwards
1145 To add things to an C<end> action that are called I<after> rendering,
1146 you can set it up like this:
1148 sub render : ActionClass('RenderView') { }
1151 my ( $self, $c ) = @_;
1152 $c->forward('render');
1160 A Catalyst application is driven by one or more Controller
1161 modules. There are a number of ways that Catalyst can decide which of
1162 the methods in your controller modules it should call. Controller
1163 methods are also called actions, because they determine how your
1164 catalyst application should (re-)act to any given URL. When the
1165 application is started up, catalyst looks at all your actions, and
1166 decides which URLs they map to.
1168 =head3 Type attributes
1170 Each action is a normal method in your controller, except that it has an
1171 L<attribute|http://search.cpan.org/~nwclark/perl-5.8.7/lib/attributes.pm>
1172 attached. These can be one of several types.
1174 Assume our Controller module starts with the following package declaration:
1176 package MyApp::Controller::Buckets;
1178 and we are running our application on localhost, port 3000 (the test
1185 A Path attribute also takes an argument, this can be either a relative
1186 or an absolute path. A relative path will be relative to the
1187 controller namespace, an absolute path will represent an exact
1190 sub my_handles : Path('handles') { .. }
1194 http://localhost:3000/buckets/handles
1198 sub my_handles : Path('/handles') { .. }
1202 http://localhost:3000/handles
1206 When using a Local attribute, no parameters are needed, instead, the
1207 name of the action is matched in the URL. The namespaces created by
1208 the name of the controller package is always part of the URL.
1210 sub my_handles : Local { .. }
1214 http://localhost:3000/buckets/my_handles
1218 A Global attribute is similar to a Local attribute, except that the
1219 namespace of the controller is ignored, and matching starts at root.
1221 sub my_handles : Global { .. }
1225 http://localhost:3000/my_handles
1229 By now you should have figured that a Regex attribute is just what it
1230 sounds like. This one takes a regular expression, and matches starting
1231 from root. These differ from the rest as they can match multiple URLs.
1233 sub my_handles : Regex('^handles') { .. }
1237 http://localhost:3000/handles
1241 http://localhost:3000/handles_and_other_parts
1247 A LocalRegex is similar to a Regex, except it only matches below the current
1248 controller namespace.
1250 sub my_handles : LocalRegex(^handles') { .. }
1254 http://localhost:3000/buckets/handles
1258 http://localhost:3000/buckets/handles_and_other_parts
1264 Last but not least, there is the Private attribute, which allows you
1265 to create your own internal actions, which can be forwarded to, but
1266 won't be matched as URLs.
1268 sub my_handles : Private { .. }
1270 becomes nothing at all..
1272 Catalyst also predefines some special Private actions, which you can
1273 override, these are:
1279 The default action will be called, if no other matching action is
1280 found. If you don't have one of these in your namespace, or any sub
1281 part of your namespace, you'll get an error page instead. If you want
1282 to find out where it was the user was trying to go, you can look in
1283 the request object using C<< $c->req->path >>.
1285 sub default : Private { .. }
1287 works for all unknown URLs, in this controller namespace, or every one
1288 if put directly into MyApp.pm.
1292 The index action is called when someone tries to visit the exact
1293 namespace of your controller. If index, default and matching Path
1294 actions are defined, then index will be used instead of default and
1297 sub index : Private { .. }
1301 http://localhost:3000/buckets
1305 The begin action is called at the beginning of every request involving
1306 this namespace directly, before other matching actions are called. It
1307 can be used to set up variables/data for this particular part of your
1308 app. A single begin action is called, its always the one most relevant
1309 to the current namespace.
1311 sub begin : Private { .. }
1315 http://localhost:3000/bucket/(anything)?
1321 Like begin, this action is always called for the namespace it is in,
1322 after every other action has finished. It is commonly used to forward
1323 processing to the View component. A single end action is called, its
1324 always the one most relevant to the current namespace.
1327 sub end : Private { .. }
1329 is called once after any actions when
1331 http://localhost:3000/bucket/(anything)?
1337 Lastly, the auto action is magic in that B<every> auto action in the
1338 chain of paths up to and including the ending namespace, will be
1339 called. (In contrast, only one of the begin/end/default actions will
1340 be called, the relevant one).
1343 sub auto : Private { .. }
1347 sub auto : Private { .. }
1349 will both be called when visiting
1351 http://localhost:3000/bucket/(anything)?
1357 =head3 A word of warning
1359 Due to possible namespace conflicts with Plugins, it is advised to
1360 only put the pre-defined Private actions in your main MyApp.pm file,
1361 all others should go in a Controller module.
1363 =head3 More Information
1365 L<http://search.cpan.org/author/SRI/Catalyst-5.61/lib/Catalyst/Manual/Intro.pod>
1367 L<http://dev.catalyst.perl.org/wiki/FlowChart>
1369 =head2 Component-based Subrequests
1371 See L<Catalyst::Plugin::SubRequest>.
1375 =head3 Single file upload with Catalyst
1377 To implement uploads in Catalyst, you need to have a HTML form similar to
1380 <form action="/upload" method="post" enctype="multipart/form-data">
1381 <input type="hidden" name="form_submit" value="yes">
1382 <input type="file" name="my_file">
1383 <input type="submit" value="Send">
1386 It's very important not to forget C<enctype="multipart/form-data"> in
1389 Catalyst Controller module 'upload' action:
1391 sub upload : Global {
1392 my ($self, $c) = @_;
1394 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1396 if ( my $upload = $c->request->upload('my_file') ) {
1398 my $filename = $upload->filename;
1399 my $target = "/tmp/upload/$filename";
1401 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1402 die( "Failed to copy '$filename' to '$target': $!" );
1407 $c->stash->{template} = 'file_upload.html';
1410 =head3 Multiple file upload with Catalyst
1412 Code for uploading multiple files from one form needs a few changes:
1414 The form should have this basic structure:
1416 <form action="/upload" method="post" enctype="multipart/form-data">
1417 <input type="hidden" name="form_submit" value="yes">
1418 <input type="file" name="file1" size="50"><br>
1419 <input type="file" name="file2" size="50"><br>
1420 <input type="file" name="file3" size="50"><br>
1421 <input type="submit" value="Send">
1424 And in the controller:
1426 sub upload : Local {
1427 my ($self, $c) = @_;
1429 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1431 for my $field ( $c->req->upload ) {
1433 my $upload = $c->req->upload($field);
1434 my $filename = $upload->filename;
1435 my $target = "/tmp/upload/$filename";
1437 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1438 die( "Failed to copy '$filename' to '$target': $!" );
1443 $c->stash->{template} = 'file_upload.html';
1446 C<for my $field ($c-E<gt>req->upload)> loops automatically over all file
1447 input fields and gets input names. After that is basic file saving code,
1448 just like in single file upload.
1450 Notice: C<die>ing might not be what you want to do, when an error
1451 occurs, but it works as an example. A better idea would be to store
1452 error C<$!> in $c->stash->{error} and show a custom error template
1453 displaying this message.
1455 For more information about uploads and usable methods look at
1456 L<Catalyst::Request::Upload> and L<Catalyst::Request>.
1458 =head2 Forwarding with arguments
1460 Sometimes you want to pass along arguments when forwarding to another
1461 action. As of version 5.30, arguments can be passed in the call to
1462 C<forward>; in earlier versions, you can manually set the arguments in
1463 the Catalyst Request object:
1465 # version 5.30 and later:
1466 $c->forward('/wherever', [qw/arg1 arg2 arg3/]);
1469 $c->req->args([qw/arg1 arg2 arg3/]);
1470 $c->forward('/wherever');
1472 (See the L<Catalyst::Manual::Intro> Flow_Control section for more
1473 information on passing arguments via C<forward>.)
1478 The recipes below describe aspects of the deployment process,
1479 including web server engines and tips to improve application efficiency.
1481 =head2 mod_perl Deployment
1483 mod_perl is the best solution for many applications, but we'll list some pros
1484 and cons so you can decide for yourself. The other production deployment
1485 option is FastCGI, for which see below.
1491 mod_perl is very fast and your app will benefit from being loaded in memory
1492 within each Apache process.
1494 =head4 Shared memory for multiple apps
1496 If you need to run several Catalyst apps on the same server, mod_perl will
1497 share the memory for common modules.
1503 Since your application is fully loaded in memory, every Apache process will
1504 be rather large. This means a large Apache process will be tied up while
1505 serving static files, large files, or dealing with slow clients. For this
1506 reason, it is best to run a two-tiered web architecture with a lightweight
1507 frontend server passing dynamic requests to a large backend mod_perl
1512 Any changes made to the core code of your app require a full Apache restart.
1513 Catalyst does not support Apache::Reload or StatINC. This is another good
1514 reason to run a frontend web server where you can set up an
1515 C<ErrorDocument 502> page to report that your app is down for maintenance.
1517 =head4 Cannot run multiple versions of the same app
1519 It is not possible to run two different versions of the same application in
1520 the same Apache instance because the namespaces will collide.
1524 Now that we have that out of the way, let's talk about setting up mod_perl
1525 to run a Catalyst app.
1527 =head4 1. Install Catalyst::Engine::Apache
1529 You should install the latest versions of both Catalyst and
1530 Catalyst::Engine::Apache. The Apache engines were separated from the
1531 Catalyst core in version 5.50 to allow for updates to the engine without
1532 requiring a new Catalyst release.
1534 =head4 2. Install Apache with mod_perl
1536 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
1537 recommended. With Apache 2, make sure you are using the prefork MPM and not
1538 the worker MPM. The reason for this is that many Perl modules are not
1539 thread-safe and may have problems running within the threaded worker
1540 environment. Catalyst is thread-safe however, so if you know what you're
1541 doing, you may be able to run using worker.
1543 In Debian, the following commands should get you going.
1545 apt-get install apache2-mpm-prefork
1546 apt-get install libapache2-mod-perl2
1548 =head4 3. Configure your application
1550 Every Catalyst application will automagically become a mod_perl handler
1551 when run within mod_perl. This makes the configuration extremely easy.
1552 Here is a basic Apache 2 configuration.
1554 PerlSwitches -I/var/www/MyApp/lib
1559 PerlResponseHandler MyApp
1562 The most important line here is C<PerlModule MyApp>. This causes mod_perl
1563 to preload your entire application into shared memory, including all of your
1564 controller, model, and view classes and configuration. If you have -Debug
1565 mode enabled, you will see the startup output scroll by when you first
1568 For an example Apache 1.3 configuration, please see the documentation for
1569 L<Catalyst::Engine::Apache::MP13>.
1573 That's it, your app is now a full-fledged mod_perl application! Try it out
1574 by going to http://your.server.com/.
1576 =head3 Other Options
1578 =head4 Non-root location
1580 You may not always want to run your app at the root of your server or virtual
1581 host. In this case, it's a simple change to run at any non-root location
1586 PerlResponseHandler MyApp
1589 When running this way, it is best to make use of the C<uri_for> method in
1590 Catalyst for constructing correct links.
1592 =head4 Static file handling
1594 Static files can be served directly by Apache for a performance boost.
1596 DocumentRoot /var/www/MyApp/root
1598 SetHandler default-handler
1601 This will let all files within root/static be handled directly by Apache. In
1602 a two-tiered setup, the frontend server should handle static files.
1603 The configuration to do this on the frontend will vary.
1605 The same is accomplished in lighttpd with the following snippet:
1607 $HTTP["url"] !~ "^/(?:img/|static/|css/|favicon.ico$)" {
1611 "socket" => "/tmp/myapp.socket",
1612 "check-local" => "disable",
1618 Which serves everything in the img, static, css directories
1619 statically, as well as the favicon file.
1621 Note the path of the application needs to be stated explicitly in the
1622 web server configuration for both these recipes.
1624 =head2 Catalyst on shared hosting
1626 So, you want to put your Catalyst app out there for the whole world to
1627 see, but you don't want to break the bank. There is an answer - if you
1628 can get shared hosting with FastCGI and a shell, you can install your
1629 Catalyst app in a local directory on your shared host. First, run
1631 perl -MCPAN -e shell
1633 and go through the standard CPAN configuration process. Then exit out
1634 without installing anything. Next, open your .bashrc and add
1636 export PATH=$HOME/local/bin:$HOME/local/script:$PATH
1637 perlversion=`perl -v | grep 'built for' | awk '{print $4}' | sed -e 's/v//;'`
1638 export PERL5LIB=$HOME/local/share/perl/$perlversion:$HOME/local/lib/perl/$perlversion:$HOME/local/lib:$PERL5LIB
1640 and log out, then back in again (or run C<". .bashrc"> if you
1641 prefer). Finally, edit C<.cpan/CPAN/MyConfig.pm> and add
1643 'make_install_arg' => qq[SITEPREFIX=$ENV{HOME}/local],
1644 'makepl_arg' => qq[INSTALLDIRS=site install_base=$ENV{HOME}/local],
1646 Now you can install the modules you need using CPAN as normal; they
1647 will be installed into your local directory, and perl will pick them
1648 up. Finally, change directory into the root of your virtual host and
1649 symlink your application's script directory in:
1651 cd path/to/mydomain.com
1652 ln -s ~/lib/MyApp/script script
1654 And add the following lines to your .htaccess file (assuming the server
1655 is setup to handle .pl as fcgi - you may need to rename the script to
1656 myapp_fastcgi.fcgi and/or use a SetHandler directive):
1659 RewriteCond %{REQUEST_URI} !^/?script/myapp_fastcgi.pl
1660 RewriteRule ^(.*)$ script/myapp_fastcgi.pl/$1 [PT,L]
1662 Now C<http://mydomain.com/> should now Just Work. Congratulations, now
1663 you can tell your friends about your new website (or in our case, tell
1664 the client it's time to pay the invoice :) )
1666 =head2 FastCGI Deployment
1668 FastCGI is a high-performance extension to CGI. It is suitable
1669 for production environments.
1675 FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you;
1676 your app runs as multiple persistent processes ready to receive connections
1677 from the web server.
1681 When using external FastCGI servers, your application runs as a standalone
1682 application server. It may be restarted independently from the web server.
1683 This allows for a more robust environment and faster reload times when
1684 pushing new app changes. The frontend server can even be configured to
1685 display a friendly "down for maintenance" page while the application is
1688 =head4 Load-balancing
1690 You can launch your application on multiple backend servers and allow the
1691 frontend web server to load-balance between all of them. And of course, if
1692 one goes down, your app continues to run fine.
1694 =head4 Multiple versions of the same app
1696 Each FastCGI application is a separate process, so you can run different
1697 versions of the same app on a single server.
1699 =head4 Can run with threaded Apache
1701 Since your app is not running inside of Apache, the faster mpm_worker module
1702 can be used without worrying about the thread safety of your application.
1706 =head4 More complex environment
1708 With FastCGI, there are more things to monitor and more processes running
1709 than when using mod_perl.
1713 =head4 1. Install Apache with mod_fastcgi
1715 mod_fastcgi for Apache is a third party module, and can be found at
1716 L<http://www.fastcgi.com/>. It is also packaged in many distributions,
1717 for example, libapache2-mod-fastcgi in Debian.
1719 =head4 2. Configure your application
1721 # Serve static content directly
1722 DocumentRoot /var/www/MyApp/root
1723 Alias /static /var/www/MyApp/root/static
1725 FastCgiServer /var/www/MyApp/script/myapp_fastcgi.pl -processes 3
1726 Alias /myapp/ /var/www/MyApp/script/myapp_fastcgi.pl/
1728 # Or, run at the root
1729 Alias / /var/www/MyApp/script/myapp_fastcgi.pl/
1731 The above commands will launch 3 app processes and make the app available at
1734 =head3 Standalone server mode
1736 While not as easy as the previous method, running your app as an external
1737 server gives you much more flexibility.
1739 First, launch your app as a standalone server listening on a socket.
1741 script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5 -p /tmp/myapp.pid -d
1743 You can also listen on a TCP port if your web server is not on the same
1746 script/myapp_fastcgi.pl -l :8080 -n 5 -p /tmp/myapp.pid -d
1748 You will probably want to write an init script to handle starting/stopping
1749 of the app using the pid file.
1751 Now, we simply configure Apache to connect to the running server.
1753 # 502 is a Bad Gateway error, and will occur if the backend server is down
1754 # This allows us to display a friendly static page that says "down for
1756 Alias /_errors /var/www/MyApp/root/error-pages
1757 ErrorDocument 502 /_errors/502.html
1759 FastCgiExternalServer /tmp/myapp.fcgi -socket /tmp/myapp.socket
1760 Alias /myapp/ /tmp/myapp.fcgi/
1762 # Or, run at the root
1763 Alias / /tmp/myapp.fcgi/
1767 L<Catalyst::Engine::FastCGI>.
1769 =head2 Development server deployment
1771 The development server is a mini web server written in perl. If you
1772 expect a low number of hits or you don't need mod_perl/FastCGI speed,
1773 you could use the development server as the application server with a
1774 lightweight proxy web server at the front. However, consider using
1775 L<Catalyst::Engine::HTTP::POE> for this kind of deployment instead, since
1776 it can better handle multiple concurrent requests without forking, or can
1777 prefork a set number of servers for improved performance.
1781 As this is an application server setup, the pros are the same as
1782 FastCGI (with the exception of speed).
1787 The development server is what you create your code on, so if it works
1788 here, it should work in production!
1794 Not as fast as mod_perl or FastCGI. Needs to fork for each request
1795 that comes in - make sure static files are served by the web server to
1800 =head4 Start up the development server
1802 script/myapp_server.pl -p 8080 -k -f -pidfile=/tmp/myapp.pid
1804 You will probably want to write an init script to handle stop/starting
1805 the app using the pid file.
1807 =head4 Configuring Apache
1809 Make sure mod_proxy is enabled and add:
1811 # Serve static content directly
1812 DocumentRoot /var/www/MyApp/root
1813 Alias /static /var/www/MyApp/root/static
1820 ProxyPass / http://localhost:8080/
1821 ProxyPassReverse / http://localhost:8080/
1823 You can wrap the above within a VirtualHost container if you want
1824 different apps served on the same host.
1826 =head2 Quick deployment: Building PAR Packages
1828 You have an application running on your development box, but then you
1829 have to quickly move it to another one for
1830 demonstration/deployment/testing...
1832 PAR packages can save you from a lot of trouble here. They are usual Zip
1833 files that contain a blib tree; you can even include all prereqs and a
1834 perl interpreter by setting a few flags!
1836 =head3 Follow these few points to try it out!
1838 1. Install Catalyst and PAR 0.89 (or later)
1840 % perl -MCPAN -e 'install Catalyst'
1842 % perl -MCPAN -e 'install PAR'
1845 2. Create a application
1851 Recent versions of Catalyst (5.62 and up) include
1852 L<Module::Install::Catalyst>, which simplifies the process greatly. From the shell in your application directory:
1857 Congratulations! Your package "myapp.par" is ready, the following
1858 steps are just optional.
1860 3. Test your PAR package with "parl" (no typo)
1864 [parl] myapp[.par] [script] [arguments]
1867 parl myapp.par myapp_server.pl -r
1877 % parl myapp.par myapp_server.pl
1878 You can connect to your server at http://localhost:3000
1880 Yes, this nifty little starter application gets automatically included.
1881 You can also use "catalyst_par_script('myapp_server.pl')" to set a
1882 default script to execute.
1884 6. Want to create a binary that includes the Perl interpreter?
1886 % pp -o myapp myapp.par
1887 % ./myapp myapp_server.pl
1888 You can connect to your server at http://localhost:3000
1890 =head2 Serving static content
1892 Serving static content in Catalyst used to be somewhat tricky; the use
1893 of L<Catalyst::Plugin::Static::Simple> makes everything much easier.
1894 This plugin will automatically serve your static content during development,
1895 but allows you to easily switch to Apache (or other server) in a
1896 production environment.
1898 =head3 Introduction to Static::Simple
1900 Static::Simple is a plugin that will help to serve static content for your
1901 application. By default, it will serve most types of files, excluding some
1902 standard Template Toolkit extensions, out of your B<root> file directory. All
1903 files are served by path, so if B<images/me.jpg> is requested, then
1904 B<root/images/me.jpg> is found and served.
1908 Using the plugin is as simple as setting your use line in MyApp.pm to include:
1910 use Catalyst qw/Static::Simple/;
1912 and already files will be served.
1916 Static content is best served from a single directory within your root
1917 directory. Having many different directories such as C<root/css> and
1918 C<root/images> requires more code to manage, because you must separately
1919 identify each static directory--if you decide to add a C<root/js>
1920 directory, you'll need to change your code to account for it. In
1921 contrast, keeping all static directories as subdirectories of a main
1922 C<root/static> directory makes things much easier to manage. Here's an
1923 example of a typical root directory structure:
1927 root/controller/stuff.tt
1930 root/static/css/main.css
1931 root/static/images/logo.jpg
1932 root/static/js/code.js
1935 All static content lives under C<root/static>, with everything else being
1936 Template Toolkit files.
1942 You may of course want to change the default locations, and make
1943 Static::Simple look somewhere else, this is as easy as:
1945 MyApp->config->{static}->{include_path} = [
1946 MyApp->config->{root},
1950 When you override include_path, it will not automatically append the
1951 normal root path, so you need to add it yourself if you still want
1952 it. These will be searched in order given, and the first matching file
1955 =item Static directories
1957 If you want to force some directories to be only static, you can set
1958 them using paths relative to the root dir, or regular expressions:
1960 MyApp->config->{static}->{dirs} = [
1965 =item File extensions
1967 By default, the following extensions are not served (that is, they will
1968 be processed by Catalyst): B<tmpl, tt, tt2, html, xhtml>. This list can
1971 MyApp->config->{static}->{ignore_extensions} = [
1972 qw/tmpl tt tt2 html xhtml/
1975 =item Ignoring directories
1977 Entire directories can be ignored. If used with include_path,
1978 directories relative to the include_path dirs will also be ignored:
1980 MyApp->config->{static}->{ignore_dirs} = [ qw/tmpl css/ ];
1984 =head3 More information
1986 L<http://search.cpan.org/dist/Catalyst-Plugin-Static-Simple/>
1988 =head3 Serving manually with the Static plugin with HTTP::Daemon (myapp_server.pl)
1990 In some situations you might want to control things more directly,
1991 using L<Catalyst::Plugin::Static>.
1993 In your main application class (MyApp.pm), load the plugin:
1995 use Catalyst qw/-Debug FormValidator Static OtherPlugin/;
1997 You will also need to make sure your end method does I<not> forward
1998 static content to the view, perhaps like this:
2001 my ( $self, $c ) = @_;
2003 $c->forward( 'MyApp::View::TT' )
2004 unless ( $c->res->body || !$c->stash->{template} );
2007 This code will only forward to the view if a template has been
2008 previously defined by a controller and if there is not already data in
2009 C<$c-E<gt>res-E<gt>body>.
2011 Next, create a controller to handle requests for the /static path. Use
2012 the Helper to save time. This command will create a stub controller as
2013 C<lib/MyApp/Controller/Static.pm>.
2015 $ script/myapp_create.pl controller Static
2017 Edit the file and add the following methods:
2019 # serve all files under /static as static files
2020 sub default : Path('/static') {
2021 my ( $self, $c ) = @_;
2023 # Optional, allow the browser to cache the content
2024 $c->res->headers->header( 'Cache-Control' => 'max-age=86400' );
2026 $c->serve_static; # from Catalyst::Plugin::Static
2029 # also handle requests for /favicon.ico
2030 sub favicon : Path('/favicon.ico') {
2031 my ( $self, $c ) = @_;
2036 You can also define a different icon for the browser to use instead of
2037 favicon.ico by using this in your HTML header:
2039 <link rel="icon" href="/static/myapp.ico" type="image/x-icon" />
2041 =head3 Common problems with the Static plugin
2043 The Static plugin makes use of the C<shared-mime-info> package to
2044 automatically determine MIME types. This package is notoriously
2045 difficult to install, especially on win32 and OS X. For OS X the easiest
2046 path might be to install Fink, then use C<apt-get install
2047 shared-mime-info>. Restart the server, and everything should be fine.
2049 Make sure you are using the latest version (>= 0.16) for best
2050 results. If you are having errors serving CSS files, or if they get
2051 served as text/plain instead of text/css, you may have an outdated
2052 shared-mime-info version. You may also wish to simply use the following
2053 code in your Static controller:
2055 if ($c->req->path =~ /css$/i) {
2056 $c->serve_static( "text/css" );
2061 =head3 Serving Static Files with Apache
2063 When using Apache, you can bypass Catalyst and any Static
2064 plugins/controllers controller by intercepting requests for the
2065 C<root/static> path at the server level. All that is required is to
2066 define a DocumentRoot and add a separate Location block for your static
2067 content. Here is a complete config for this application under mod_perl
2071 use lib qw(/var/www/MyApp/lib);
2076 ServerName myapp.example.com
2077 DocumentRoot /var/www/MyApp/root
2079 SetHandler perl-script
2082 <LocationMatch "/(static|favicon.ico)">
2083 SetHandler default-handler
2087 And here's a simpler example that'll get you started:
2089 Alias /static/ "/my/static/files/"
2090 <Location "/static">
2096 Catalyst makes it easy to employ several different types of caching to
2097 speed up your applications.
2099 =head3 Cache Plugins
2101 There are three wrapper plugins around common CPAN cache modules:
2102 Cache::FastMmap, Cache::FileCache, and Cache::Memcached. These can be
2103 used to cache the result of slow operations.
2105 This very page you're viewing makes use of the FileCache plugin to cache the
2106 rendered XHTML version of the source POD document. This is an ideal
2107 application for a cache because the source document changes infrequently but
2108 may be viewed many times.
2110 use Catalyst qw/Cache::FileCache/;
2115 sub render_pod : Local {
2116 my ( self, $c ) = @_;
2118 # the cache is keyed on the filename and the modification time
2119 # to check for updates to the file.
2120 my $file = $c->path_to( 'root', '2005', '11.pod' );
2121 my $mtime = ( stat $file )->mtime;
2123 my $cached_pod = $c->cache->get("$file $mtime");
2124 if ( !$cached_pod ) {
2125 $cached_pod = do_slow_pod_rendering();
2126 # cache the result for 12 hours
2127 $c->cache->set( "$file $mtime", $cached_pod, '12h' );
2129 $c->stash->{pod} = $cached_pod;
2132 We could actually cache the result forever, but using a value such as 12 hours
2133 allows old entries to be automatically expired when they are no longer needed.
2137 Another method of caching is to cache the entire HTML page. While this is
2138 traditionally handled by a front-end proxy server like Squid, the Catalyst
2139 PageCache plugin makes it trivial to cache the entire output from
2140 frequently-used or slow actions.
2142 Many sites have a busy content-filled front page that might look something
2143 like this. It probably takes a while to process, and will do the exact same
2144 thing for every single user who views the page.
2146 sub front_page : Path('/') {
2147 my ( $self, $c ) = @_;
2149 $c->forward( 'get_news_articles' );
2150 $c->forward( 'build_lots_of_boxes' );
2151 $c->forward( 'more_slow_stuff' );
2153 $c->stash->{template} = 'index.tt';
2156 We can add the PageCache plugin to speed things up.
2158 use Catalyst qw/Cache::FileCache PageCache/;
2160 sub front_page : Path ('/') {
2161 my ( $self, $c ) = @_;
2163 $c->cache_page( 300 );
2165 # same processing as above
2168 Now the entire output of the front page, from <html> to </html>, will be
2169 cached for 5 minutes. After 5 minutes, the next request will rebuild the
2170 page and it will be re-cached.
2172 Note that the page cache is keyed on the page URI plus all parameters, so
2173 requests for / and /?foo=bar will result in different cache items. Also,
2174 only GET requests will be cached by the plugin.
2176 You can even get that front-end Squid proxy to help out by enabling HTTP
2177 headers for the cached page.
2179 MyApp->config->{page_cache}->{set_http_headers} = 1;
2181 This would now set the following headers so proxies and browsers may cache
2182 the content themselves.
2184 Cache-Control: max-age=($expire_time - time)
2185 Expires: $expire_time
2186 Last-Modified: $cache_created_time
2188 =head3 Template Caching
2190 Template Toolkit provides support for caching compiled versions of your
2191 templates. To enable this in Catalyst, use the following configuration.
2192 TT will cache compiled templates keyed on the file mtime, so changes will
2193 still be automatically detected.
2195 package MyApp::View::TT;
2199 use base 'Catalyst::View::TT';
2201 __PACKAGE__->config(
2202 COMPILE_DIR => '/tmp/template_cache',
2209 See the documentation for each cache plugin for more details and other
2210 available configuration options.
2212 L<Catalyst::Plugin::Cache::FastMmap>
2213 L<Catalyst::Plugin::Cache::FileCache>
2214 L<Catalyst::Plugin::Cache::Memcached>
2215 L<Catalyst::Plugin::PageCache>
2216 L<http://search.cpan.org/dist/Template-Toolkit/lib/Template/Manual/Config.pod#Caching_and_Compiling_Options>
2220 Testing is an integral part of the web application development
2221 process. Tests make multi developer teams easier to coordinate, and
2222 they help ensure that there are no nasty surprises after upgrades or
2227 Catalyst provides a convenient way of testing your application during
2228 development and before deployment in a real environment.
2230 C<Catalyst::Test> makes it possible to run the same tests both locally
2231 (without an external daemon) and against a remote server via HTTP.
2235 Let's examine a skeleton application's C<t/> directory:
2237 mundus:~/MyApp chansen$ ls -l t/
2239 -rw-r--r-- 1 chansen chansen 95 18 Dec 20:50 01app.t
2240 -rw-r--r-- 1 chansen chansen 190 18 Dec 20:50 02pod.t
2241 -rw-r--r-- 1 chansen chansen 213 18 Dec 20:50 03podcoverage.t
2247 Verifies that the application loads, compiles, and returns a successful
2252 Verifies that all POD is free from errors. Only executed if the C<TEST_POD>
2253 environment variable is true.
2255 =item C<03podcoverage.t>
2257 Verifies that all methods/functions have POD coverage. Only executed if the
2258 C<TEST_POD> environment variable is true.
2262 =head3 Creating tests
2264 mundus:~/MyApp chansen$ cat t/01app.t | perl -ne 'printf( "%2d %s", $., $_ )'
2265 1 use Test::More tests => 2;
2266 2 use_ok( Catalyst::Test, 'MyApp' );
2268 4 ok( request('/')->is_success );
2270 The first line declares how many tests we are going to run, in this case
2271 two. The second line tests and loads our application in test mode. The
2272 fourth line verifies that our application returns a successful response.
2274 C<Catalyst::Test> exports two functions, C<request> and C<get>. Each can
2275 take three different arguments:
2279 =item A string which is a relative or absolute URI.
2281 request('/my/path');
2282 request('http://www.host.com/my/path');
2284 =item An instance of C<URI>.
2286 request( URI->new('http://www.host.com/my/path') );
2288 =item An instance of C<HTTP::Request>.
2290 request( HTTP::Request->new( GET => 'http://www.host.com/my/path') );
2294 C<request> returns an instance of C<HTTP::Response> and C<get> returns the
2295 content (body) of the response.
2297 =head3 Running tests locally
2299 mundus:~/MyApp chansen$ CATALYST_DEBUG=0 TEST_POD=1 prove --lib lib/ t/
2300 t/01app............ok
2301 t/02pod............ok
2302 t/03podcoverage....ok
2303 All tests successful.
2304 Files=3, Tests=4, 2 wallclock secs ( 1.60 cusr + 0.36 csys = 1.96 CPU)
2306 C<CATALYST_DEBUG=0> ensures that debugging is off; if it's enabled you
2307 will see debug logs between tests.
2309 C<TEST_POD=1> enables POD checking and coverage.
2311 C<prove> A command-line tool that makes it easy to run tests. You can
2312 find out more about it from the links below.
2314 =head3 Running tests remotely
2316 mundus:~/MyApp chansen$ CATALYST_SERVER=http://localhost:3000/ prove --lib lib/ t/01app.t
2318 All tests successful.
2319 Files=1, Tests=2, 0 wallclock secs ( 0.40 cusr + 0.01 csys = 0.41 CPU)
2321 C<CATALYST_SERVER=http://localhost:3000/> is the absolute deployment URI of
2322 your application. In C<CGI> or C<FastCGI> it should be the host and path
2325 =head3 C<Test::WWW::Mechanize> and Catalyst
2327 Be sure to check out C<Test::WWW::Mechanize::Catalyst>. It makes it easy to
2328 test HTML, forms and links. A short example of usage:
2330 use Test::More tests => 6;
2331 use_ok( Test::WWW::Mechanize::Catalyst, 'MyApp' );
2333 my $mech = Test::WWW::Mechanize::Catalyst->new;
2334 $mech->get_ok("http://localhost/", 'Got index page');
2335 $mech->title_like( qr/^MyApp on Catalyst/, 'Got right index title' );
2336 ok( $mech->find_link( text_regex => qr/^Wiki/i ), 'Found link to Wiki' );
2337 ok( $mech->find_link( text_regex => qr/^Mailing-List/i ), 'Found link to Mailing-List' );
2338 ok( $mech->find_link( text_regex => qr/^IRC channel/i ), 'Found link to IRC channel' );
2340 =head3 Further Reading
2344 =item Catalyst::Test
2346 L<http://search.cpan.org/dist/Catalyst/lib/Catalyst/Test.pm>
2348 =item Test::WWW::Mechanize::Catalyst
2350 L<http://search.cpan.org/dist/Test-WWW-Mechanize-Catalyst/lib/Test/WWW/Mechanize/Catalyst.pm>
2352 =item Test::WWW::Mechanize
2354 L<http://search.cpan.org/dist/Test-WWW-Mechanize/Mechanize.pm>
2356 =item WWW::Mechanize
2358 L<http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm>
2360 =item LWP::UserAgent
2362 L<http://search.cpan.org/dist/libwww-perl/lib/LWP/UserAgent.pm>
2366 L<http://search.cpan.org/dist/libwww-perl/lib/HTML/Form.pm>
2370 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Message.pm>
2374 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request.pm>
2376 =item HTTP::Request::Common
2378 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request/Common.pm>
2380 =item HTTP::Response
2382 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Response.pm>
2386 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Status.pm>
2390 L<http://search.cpan.org/dist/URI/URI.pm>
2394 L<http://search.cpan.org/dist/Test-Simple/lib/Test/More.pm>
2398 L<http://search.cpan.org/dist/Test-Pod/Pod.pm>
2400 =item Test::Pod::Coverage
2402 L<http://search.cpan.org/dist/Test-Pod-Coverage/Coverage.pm>
2404 =item prove (Test::Harness)
2406 L<http://search.cpan.org/dist/Test-Harness/bin/prove>
2410 =head3 More Information
2412 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::Roles>
2413 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::ACL>
2417 Sebastian Riedel C<sri@oook.de>
2419 Danijel Milicevic C<me@danijel.de>
2421 Viljo Marrandi C<vilts@yahoo.com>
2423 Marcus Ramberg C<mramberg@cpan.org>
2425 Jesse Sheidlower C<jester@panix.com>
2427 Andy Grundman C<andy@hybridized.org>
2429 Chisel Wright C<pause@herlpacker.co.uk>
2431 Will Hawes C<info@whawes.co.uk>
2433 Gavin Henry C<ghenry@perl.me.uk>
2435 Kieren Diment C<kd@totaldatasolution.com>
2439 This document is free, you can redistribute it and/or modify it
2440 under the same terms as Perl itself.