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.
163 =head3 Using Config::General
165 L<Config::General|Config::General> is a method for creating flexible
166 and readable configuration files. It's a great way to keep your
167 Catalyst application configuration in one easy-to-understand location.
169 Now create C<myapp.conf> in your application home:
173 # session; perldoc Catalyst::Plugin::Session::FastMmap
177 storage /tmp/myapp.session
180 # emails; perldoc Catalyst::Plugin::Email
181 # this passes options as an array :(
185 This is equivalent to:
187 # configure base package
188 __PACKAGE__->config( name => MyApp );
189 # configure authentication
190 __PACKAGE__->config->{authentication} = {
191 user_class => 'MyApp::Model::MyDB::Customer',
195 __PACKAGE__->config->{session} = {
199 # configure email sending
200 __PACKAGE__->config->{email} = [qw/SMTP localhost/];
202 See also L<Config::General|Config::General>.
204 =head1 Skipping your VCS's directories
206 Catalyst uses Module::Pluggable to load Models, Views and Controllers.
207 Module::Pluggable will scan through all directories and load modules
208 it finds. Sometimes you might want to skip some of these directories,
209 for example when your version control system makes a subdirectory with
210 meta-information in every version-controlled directory. While
211 Catalyst skips subversion and CVS directories already, there are other
212 source control systems. Here is the configuration you need to add
213 their directories to the list to skip.
215 You can make catalyst skip these directories using the Catalyst config:
217 # Configure the application
220 setup_components => { except => qr/SCCS/ },
223 See the Module::Pluggable manual page for more information on B<except>
226 =head1 Users and Access Control
228 Most multiuser, and some single user web applications require that
229 users identify themselves, and the application is often required to
230 define those roles. The recipes below describe some ways of doing
233 =head2 Authentication (logging in)
235 This is extensively covered in other documentation; see in particular
236 L<Catalyst::Plugin::Authentication> and the Authentication chapter
237 of the Tutorial at L<Catalyst::Manual::Tutorial::Authorization>.
239 =head2 Pass-through login (and other actions)
241 An easy way of having assorted actions that occur during the processing
242 of a request that are orthogonal to its actual purpose - logins, silent
243 commands etc. Provide actions for these, but when they're required for
244 something else fill e.g. a form variable __login and have a sub begin
247 sub begin : Private {
249 foreach my $action (qw/login docommand foo bar whatever/) {
250 if ($c->req->params->{"__${action}"}) {
251 $c->forward($action);
257 =head2 Role-based Authorization
259 For more advanced access control, you may want to consider using role-based
260 authorization. This means you can assign different roles to each user, e.g.
261 "user", "admin", etc.
263 The C<login> and C<logout> methods and view template are exactly the same as
264 in the previous example.
266 The L<Catalyst::Plugin::Authorization::Roles> plugin is required when
271 Authentication::Credential::Password
272 Authentication::Store::Htpasswd
276 Roles are implemented automatically when using
277 L<Catalyst::Authentication::Store::Htpasswd>:
279 # no additional role configuration required
280 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
282 Or can be set up manually when using L<Catalyst::Authentication::Store::DBIC>:
284 # Authorization using a many-to-many role relationship
285 __PACKAGE__->config->{authorization}{dbic} = {
286 'role_class' => 'My::Model::DBIC::Role',
287 'role_field' => 'name',
288 'user_role_user_field' => 'user',
290 # DBIx::Class only (omit if using Class::DBI)
291 'role_rel' => 'user_role',
293 # Class::DBI only, (omit if using DBIx::Class)
294 'user_role_class' => 'My::Model::CDBI::UserRole'
295 'user_role_role_field' => 'role',
298 To restrict access to any action, you can use the C<check_user_roles> method:
300 sub restricted : Local {
301 my ( $self, $c ) = @_;
303 $c->detach("unauthorized")
304 unless $c->check_user_roles( "admin" );
306 # do something restricted here
309 You can also use the C<assert_user_roles> method. This just gives an
310 error if the current user does not have one of the required roles:
312 sub also_restricted : Global {
313 my ( $self, $c ) = @_;
314 $c->assert_user_roles( qw/ user admin / );
317 =head2 Authentication/Authorization
319 This is done in several steps:
325 Getting the user to identify themselves, by giving you some piece of
326 information known only to you and the user. Then you can assume that
327 the user is who they say they are. This is called B<credential
332 Making sure the user only accesses functions you want them to
333 access. This is done by checking the verified users data against your
334 internal list of groups, or allowed persons for the current page.
340 The Catalyst Authentication system is made up of many interacting
341 modules, to give you the most flexibility possible.
343 =head4 Credential verifiers
345 A Credential module tables the user input, and passes it to a Store,
346 or some other system, for verification. Typically, a user object is
347 created by either this module or the Store and made accessible by a
348 C<< $c->user >> call.
352 Password - Simple username/password checking.
353 HTTPD - Checks using basic HTTP auth.
354 TypeKey - Check using the typekey system.
356 =head3 Storage backends
358 A Storage backend contains the actual data representing the users. It
359 is queried by the credential verifiers. Updating the store is not done
360 within this system, you will need to do it yourself.
364 DBIC - Storage using a database.
365 Minimal - Storage using a simple hash (for testing).
369 A User object is created by either the storage backend or the
370 credential verifier, and filled with the retrieved user information.
374 Hash - A simple hash of keys and values.
376 =head3 ACL authorization
378 ACL stands for Access Control List. The ACL plugin allows you to
379 regulate access on a path by path basis, by listing which users, or
380 roles, have access to which paths.
382 =head3 Roles authorization
384 Authorization by roles is for assigning users to groups, which can
385 then be assigned to ACLs, or just checked when needed.
389 When you have chosen your modules, all you need to do is call the C<<
390 $c->login >> method. If called with no parameters, it will try to find
391 suitable parameters, such as B<username> and B<password>, or you can
392 pass it these values.
394 =head3 Checking roles
396 Role checking is done by using the C<< $c->check_user_roles >> method,
397 this will check using the currently logged in user (via C<< $c->user
398 >>). You pass it the name of a role to check, and it returns true if
399 the user is a member.
403 use Catalyst qw/Authentication
404 Authentication::Credential::Password
405 Authentication::Store::Htpasswd
406 Authorization::Roles/;
408 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
413 if ( my $user = $c->req->param("user")
414 and my $password = $c->req->param("password") )
416 if ( $c->login( $user, $password ) ) {
417 $c->res->body( "hello " . $c->user->name );
427 sub restricted : Local {
428 my ( $self, $c ) = @_;
430 $c->detach("unauthorized")
431 unless $c->check_user_roles( "admin" );
433 # do something restricted here
436 =head3 Using authentication in a testing environment
438 Ideally, to write tests for authentication/authorization code one
439 would first set up a test database with known data, then use
440 L<Test::WWW::Mechanize::Catalyst> to simulate a user logging
441 in. Unfortunately the former can be rather awkward, which is why it's
442 a good thing that the authentication framework is so flexible.
444 Instead of using a test database, one can simply change the
445 authentication store to something a bit easier to deal with in a
446 testing environment. Additionally, this has the advantage of not
447 modifying one's database, which can be problematic if one forgets to
448 use the testing instead of production database.
452 use Catalyst::Plugin::Authentication::Store::Minimal::Backend;
454 # Sets up the user `test_user' with password `test_pass'
455 MyApp->default_auth_store(
456 Catalyst::Plugin::Authentication::Store::Minimal::Backend->new({
457 test_user => { password => 'test_pass' },
461 Now, your test code can call C<$c->login('test_user', 'test_pass')> and
462 successfully login, without messing with the database at all.
464 =head3 More information
466 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authentication> has a longer explanation.
472 Authorization is the step that comes after
473 authentication. Authentication establishes that the user agent is
474 really representing the user we think it's representing, and then
475 authorization determines what this user is allowed to do.
477 =head3 Role Based Access Control
479 Under role based access control each user is allowed to perform any
480 number of roles. For example, at a zoo no one but specially trained
481 personnel can enter the moose cage (Mynd you, møøse bites kan be
482 pretty nasti!). For example:
484 package Zoo::Controller::MooseCage;
486 sub feed_moose : Local {
487 my ( $self, $c ) = @_;
489 $c->model( "Moose" )->eat( $c->req->param("food") );
492 With this action, anyone can just come into the moose cage and feed
493 the moose, which is a very dangerous thing. We need to restrict this
494 action, so that only a qualified moose feeder can perform that action.
496 The Authorization::Roles plugin let's us perform role based access
497 control checks. Let's load it:
500 Authentication # yadda yadda
504 And now our action should look like this:
506 sub feed_moose : Local {
507 my ( $self, $c ) = @_;
509 if ( $c->check_roles( "moose_feeder" ) ) {
510 $c->model( "Moose" )->eat( $c->req->param("food") );
512 $c->stash->{error} = "unauthorized";
516 This checks C<< $c->user >>, and only if the user has B<all> the roles
517 in the list, a true value is returned.
519 C<check_roles> has a sister method, C<assert_roles>, which throws an
520 exception if any roles are missing.
522 Some roles that might actually make sense in, say, a forum application:
536 each with a distinct task (system administration versus content
539 =head3 Access Control Lists
541 Checking for roles all the time can be tedious and error prone.
543 The Authorization::ACL plugin let's us declare where we'd like checks
544 to be done automatically for us.
546 For example, we may want to completely block out anyone who isn't a
547 C<moose_feeder> from the entire C<MooseCage> controller:
549 Zoo->deny_access_unless( "/moose_cage", [qw/moose_feeder/] );
551 The role list behaves in the same way as C<check_roles>. However, the
552 ACL plugin isn't limited to just interacting with the Roles plugin. We
553 can use a code reference instead. For example, to allow either moose
554 trainers or moose feeders into the moose cage, we can create a more
557 Zoo->deny_access_unless( "/moose_cage", sub {
559 $c->check_roles( "moose_trainer" ) || $c->check_roles( "moose_feeder" );
562 The more specific a role, the earlier it will be checked. Let's say
563 moose feeders are now restricted to only the C<feed_moose> action,
564 while moose trainers get access everywhere:
566 Zoo->deny_access_unless( "/moose_cage", [qw/moose_trainer/] );
567 Zoo->allow_access_if( "/moose_cage/feed_moose", [qw/moose_feeder/]);
569 When the C<feed_moose> action is accessed the second check will be
570 made. If the user is a C<moose_feeder>, then access will be
571 immediately granted. Otherwise, the next rule in line will be tested -
572 the one checking for a C<moose_trainer>. If this rule is not
573 satisfied, access will be immediately denied.
575 Rules applied to the same path will be checked in the order they were
578 Lastly, handling access denial events is done by creating an
579 C<access_denied> private action:
581 sub access_denied : Private {
582 my ( $self, $c, $action ) = @_;
585 This action works much like auto, in that it is inherited across
586 namespaces (not like object oriented code). This means that the
587 C<access_denied> action which is B<nearest> to the action which was
588 blocked will be triggered.
590 If this action does not exist, an error will be thrown, which you can
591 clean up in your C<end> private action instead.
593 Also, it's important to note that if you restrict access to "/" then
594 C<end>, C<default>, etc will also be restricted.
596 MyApp->acl_allow_root_internals;
598 will create rules that permit access to C<end>, C<begin>, and C<auto> in the
599 root of your app (but not in any other controller).
603 Models are where application data belongs. Catalyst is exteremely
604 flexible with the kind of models that it can use. The recipes here
607 =head2 Using existing DBIC (etc.) classes with Catalyst
609 Many people have existing Model classes that they would like to use
610 with Catalyst (or, conversely, they want to write Catalyst models that
611 can be used outside of Catalyst, e.g. in a cron job). It's trivial to
612 write a simple component in Catalyst that slurps in an outside Model:
614 package MyApp::Model::DB;
615 use base qw/Catalyst::Model::DBIC::Schema/;
617 schema_class => 'Some::DBIC::Schema',
618 connect_info => ['dbi:SQLite:foo.db', '', '', {AutoCommit=>1}];
622 and that's it! Now C<Some::DBIC::Schema> is part of your
623 Cat app as C<MyApp::Model::DB>.
625 =head2 DBIx::Class as a Catalyst Model
627 See L<Catalyst::Model::DBIC::Schema>.
629 =head2 Create accessors to preload static data once per server instance
631 When you have data that you want to load just once from the model at
632 server load instead of for each request, use mk_group_accessors to
633 create accessors and tie them to resultsets in your package that
634 inherits from DBIx::Class::Schema
637 use base qw/DBIx::Class::Schema/;
638 __PACKAGE__->register_class('RESULTSOURCEMONIKER',
639 'My::Schema::RESULTSOURCE');
640 __PACKAGE__->mk_group_accessors('simple' =>
641 qw(ACCESSORNAME1 ACCESSORNAME2 ACCESSORNAMEn));
644 my ($self, @rest) = @_;
645 $self->next::method(@rest);
646 # $self is now a live My::Schema object, complete with DB connection
648 $self->ACCESSORNAME1([ $self->resultset('RESULTSOURCEMONIKER')->all ]);
649 $self->ACCESSORNAME2([ $self->resultset('RESULTSOURCEMONIKER')->search({ COLUMN => { '<' => '30' } })->all ]);
650 $self->ACCESSORNAMEn([ $self->resultset('RESULTSOURCEMONIKER')->find(1) ]);
655 and now in the controller, you can now access any of these without a
658 $c->stash->{something} = $c->model('My::Schema')->schema->ACCESSORNAMEn;
663 Unlike SOAP, XMLRPC is a very simple (and imo elegant) web-services
664 protocol, exchanging small XML messages like these:
669 TE: deflate,gzip;q=0.3
670 Connection: TE, close
674 User-Agent: SOAP::Lite/Perl/0.60
676 Content-Type: text/xml
678 <?xml version="1.0" encoding="UTF-8"?>
680 <methodName>add</methodName>
682 <param><value><int>1</int></value></param>
683 <param><value><int>2</int></value></param>
690 Date: Tue, 20 Dec 2005 07:45:55 GMT
692 Content-Type: text/xml
696 <?xml version="1.0" encoding="us-ascii"?>
699 <param><value><int>3</int></value></param>
703 Now follow these few steps to implement the application:
705 1. Install Catalyst (5.61 or later), Catalyst::Plugin::XMLRPC (0.06 or
706 later) and SOAP::Lite (for XMLRPCsh.pl).
708 2. Create an application framework:
714 3. Add the XMLRPC plugin to MyApp.pm
716 use Catalyst qw/-Debug Static::Simple XMLRPC/;
718 4. Add an API controller
720 % ./script/myapp_create.pl controller API
722 5. Add a XMLRPC redispatch method and an add method with Remote
723 attribute to lib/MyApp/Controller/API.pm
725 sub default : Private {
726 my ( $self, $c ) = @_;
731 my ( $self, $c, $a, $b ) = @_;
735 The default action is the entry point for each XMLRPC request. It will
736 redispatch every request to methods with Remote attribute in the same
739 The C<add> method is not a traditional action; it has no private or
740 public path. Only the XMLRPC dispatcher knows it exists.
742 6. That's it! You have built your first web service. Let's test it with
743 XMLRPCsh.pl (part of SOAP::Lite):
745 % ./script/myapp_server.pl
747 % XMLRPCsh.pl http://127.0.0.1:3000/api
748 Usage: method[(parameters)]
750 --- XMLRPC RESULT ---
755 Your return data type is usually auto-detected, but you can easily
756 enforce a specific one.
759 my ( $self, $c, $a, $b ) = @_;
760 return RPC::XML::int->new( $a + $b );
767 Views pertain to the display of your application. As with models,
768 catalyst is uncommonly flexible. The recipes below are just a start.
770 =head2 Catalyst::View::TT
772 One of the first things you probably want to do when starting a new
773 Catalyst application is set up your View. Catalyst doesn't care how you
774 display your data; you can choose to generate HTML, PDF files, or plain
777 Most Catalyst applications use a template system to generate their HTML,
778 and though there are several template systems available, Template
779 Toolkit is probably the most popular.
781 Once again, the Catalyst developers have done all the hard work, and
782 made things easy for the rest of us. Catalyst::View::TT provides the
783 interface to Template Toolkit, and provides Helpers which let us set it
784 up that much more easily.
786 =head3 Creating your View
788 Catalyst::View::TT provides two different helpers for us to use: TT and
793 Create a basic Template Toolkit View using the provided helper script:
795 script/myapp_create.pl view TT TT
797 This will create lib/MyApp/View/MyView.pm, which is going to be pretty
798 empty to start. However, it sets everything up that you need to get
799 started. You can now define which template you want and forward to your
803 my ( $self, $c ) = @_;
805 $c->stash->{template} = 'hello.tt';
807 $c->forward( $c->view('TT') );
810 In practice you wouldn't do the forwarding manually, but would
811 use L<Catalyst::Action::RenderView>.
815 Although the TT helper does create a functional, working view, you may
816 find yourself having to create the same template files and changing the
817 same options every time you create a new application. The TTSite helper
818 saves us even more time by creating the basic templates and setting some
819 common options for us.
821 Once again, you can use the helper script:
823 script/myapp_create.pl view TT TTSite
825 This time, the helper sets several options for us in the generated View.
827 __PACKAGE__->config({
828 CATALYST_VAR => 'Catalyst',
830 MyApp->path_to( 'root', 'src' ),
831 MyApp->path_to( 'root', 'lib' )
833 PRE_PROCESS => 'config/main',
834 WRAPPER => 'site/wrapper',
835 ERROR => 'error.tt2',
843 INCLUDE_PATH defines the directories that Template Toolkit should search
844 for the template files.
848 PRE_PROCESS is used to process configuration options which are common to
853 WRAPPER is a file which is processed with each template, usually used to
854 easily provide a common header and footer for every page.
858 In addition to setting these options, the TTSite helper also created the
859 template and config files for us! In the 'root' directory, you'll notice
860 two new directories: src and lib.
862 Several configuration files in root/lib/config are called by PRE_PROCESS.
864 The files in root/lib/site are the site-wide templates, called by
865 WRAPPER, and display the html framework, control the layout, and provide
866 the templates for the header and footer of your page. Using the template
867 organization provided makes it much easier to standardize pages and make
868 changes when they are (inevitably) needed.
870 The template files that you will create for your application will go
871 into root/src, and you don't need to worry about putting the the <html>
872 or <head> sections; just put in the content. The WRAPPER will the rest
873 of the page around your template for you.
878 Of course, having the template system include the header and footer for
879 you isn't all that we want our templates to do. We need to be able to
880 put data into our templates, and have it appear where and how we want
881 it, right? That's where the stash comes in.
883 In our controllers, we can add data to the stash, and then access it
884 from the template. For instance:
887 my ( $self, $c ) = @_;
889 $c->stash->{name} = 'Adam';
891 $c->stash->{template} = 'hello.tt';
893 $c->forward( $c->view('TT') );
898 <strong>Hello, [% name %]!</strong>
900 When you view this page, it will display "Hello, Adam!"
902 All of the information in your stash is available, by its name/key, in
903 your templates. And your data don't have to be plain, old, boring
904 scalars. You can pass array references and hash references, too.
909 my ( $self, $c ) = @_;
911 $c->stash->{names} = [ 'Adam', 'Dave', 'John' ];
913 $c->stash->{template} = 'hello.tt';
915 $c->forward( $c->view('TT') );
920 [% FOREACH name IN names %]
921 <strong>Hello, [% name %]!</strong><br />
924 This allowed us to loop through each item in the arrayref, and display a
925 line for each name that we have.
927 This is the most basic usage, but Template Toolkit is quite powerful,
928 and allows you to truly keep your presentation logic separate from the
929 rest of your application.
933 One of my favorite things about Catalyst is the ability to move an
934 application around without having to worry that everything is going to
935 break. One of the areas that used to be a problem was with the http
936 links in your template files. For example, suppose you have an
937 application installed at http://www.domain.com/Calendar. The links point
938 to "/Calendar", "/Calendar/2005", "/Calendar/2005/10", etc. If you move
939 the application to be at http://www.mydomain.com/Tools/Calendar, then
940 all of those links will suddenly break.
942 That's where $c->uri_for() comes in. This function will merge its
943 parameters with either the base location for the app, or its current
944 namespace. Let's take a look at a couple of examples.
946 In your template, you can use the following:
948 <a href="[% c.uri_for('/login') %]">Login Here</a>
950 Although the parameter starts with a forward slash, this is relative
951 to the application root, not the webserver root. This is important to
952 remember. So, if your application is installed at
953 http://www.domain.com/Calendar, then the link would be
954 http://www.mydomain.com/Calendar/Login. If you move your application
955 to a different domain or path, then that link will still be correct.
959 <a href="[% c.uri_for('2005','10', '24') %]">October, 24 2005</a>
961 The first parameter does NOT have a forward slash, and so it will be
962 relative to the current namespace. If the application is installed at
963 http://www.domain.com/Calendar. and if the template is called from
964 MyApp::Controller::Display, then the link would become
965 http://www.domain.com/Calendar/Display/2005/10/24.
967 If you want to link to a parent uri of your current namespace you can
968 prefix the arguments with multiple '../':
970 <a href="[% c.uri_for('../../view', stashed_object.id) %]">User view</a>
972 Once again, this allows you to move your application around without
973 having to worry about broken links. But there's something else, as
974 well. Since the links are generated by uri_for, you can use the same
975 template file by several different controllers, and each controller
976 will get the links that its supposed to. Since we believe in Don't
977 Repeat Yourself, this is particularly helpful if you have common
978 elements in your site that you want to keep in one file.
982 L<http://search.cpan.org/perldoc?Catalyst>
984 L<http://search.cpan.org/perldoc?Catalyst%3A%3AView%3A%3ATT>
986 L<http://search.cpan.org/perldoc?Template>
988 =head2 Adding RSS feeds
990 Adding RSS feeds to your Catalyst applications is simple. We'll see two
991 different aproaches here, but the basic premise is that you forward to
992 the normal view action first to get the objects, then handle the output
995 =head3 Using TT templates
997 This is the aproach used in Agave (L<http://dev.rawmode.org/>).
1001 $c->forward('view');
1002 $c->stash->{template}='rss.tt';
1005 Then you need a template. Here's the one from Agave:
1007 <?xml version="1.0" encoding="UTF-8"?>
1008 <rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/">
1010 <title>[ [% blog.name || c.config.name || "Agave" %] ] RSS Feed</title>
1011 <link>[% base %]</link>
1012 <description>Recent posts</description>
1013 <language>en-us</language>
1015 [% WHILE (post = posts.next) %]
1017 <title>[% post.title %]</title>
1018 <description>[% post.formatted_teaser|html%]</description>
1019 <pubDate>[% post.pub_date %]</pubDate>
1020 <guid>[% post.full_uri %]</guid>
1021 <link>[% post.full_uri %]</link>
1022 <dc:creator>[% post.author.screenname %]</dc:creator>
1028 =head3 Using XML::Feed
1030 A more robust solution is to use XML::Feed, as was done in the Catalyst
1031 Advent Calendar. Assuming we have a C<view> action that populates
1032 'entries' with some DBIx::Class iterator, the code would look something
1037 $c->forward('view'); # get the entries
1039 my $feed = XML::Feed->new('RSS');
1040 $feed->title( $c->config->{name} . ' RSS Feed' );
1041 $feed->link( $c->req->base ); # link to the site.
1042 $feed->description('Catalyst advent calendar'); Some description
1044 # Process the entries
1045 while( my $entry = $c->stash->{entries}->next ) {
1046 my $feed_entry = XML::Feed::Entry->new('RSS');
1047 $feed_entry->title($entry->title);
1048 $feed_entry->link( $c->uri_for($entry->link) );
1049 $feed_entry->issued( DateTime->from_epoch(epoch => $entry->created) );
1050 $feed->add_entry($feed_entry);
1052 $c->res->body( $feed->as_xml );
1055 A little more code in the controller, but with this approach you're
1056 pretty sure to get something that validates.
1058 Note that for both of the above aproaches, you'll need to set the
1059 content type like this:
1061 $c->res->content_type('application/rss+xml');
1065 You could generalize the second variant easily by replacing 'RSS' with a
1066 variable, so you can generate Atom feeds with the same code.
1068 Now, go ahead and make RSS feeds for all your stuff. The world *needs*
1069 updates on your goldfish!
1071 =head2 Forcing the browser to download content
1073 Sometimes you need your application to send content for download. For
1074 example, you can generate a comma-separated values (CSV) file for your
1075 users to download and import into their spreadsheet program.
1077 Let's say you have an C<Orders> controller which generates a CSV file
1078 in the C<export> action (i.e., C<http://localhost:3000/orders/export>):
1080 sub export : Local Args(0) {
1081 my ( $self, $c ) = @_;
1083 # In a real application, you'd generate this from the database
1084 my $csv = "1,5.99\n2,29.99\n3,3.99\n";
1086 $c->res->content_type('text/comma-separated-values');
1087 $c->res->body($csv);
1090 Normally the browser uses the last part of the URI to generate a
1091 filename for data it cannot display. In this case your browser would
1092 likely ask you to save a file named C<export>.
1094 Luckily you can have the browser download the content with a specific
1095 filename by setting the C<Content-Disposition> header:
1097 my $filename = 'Important Orders.csv';
1098 $c->res->header('Content-Disposition', qq[attachment; filename="$filename"]);
1100 Note the use of quotes around the filename; this ensures that any
1101 spaces in the filename are handled by the browser.
1103 Put this right before calling C<< $c->res->body >> and your browser
1104 will download a file named C<Important Orders.csv> instead of
1107 You can also use this to have the browser download content which it
1108 normally displays, such as JPEG images or even HTML. Just be sure to
1109 set the appropriate content type and disposition.
1114 Controllers are the main point of communication between the web server
1115 and your application. Here we explore some aspects of how they work.
1117 =head2 Extending RenderView (formerly DefaultEnd)
1119 The recommended approach for an C<end> action is to use
1120 L<Catalyst::Action::RenderView> (taking the place of
1121 L<Catalyst::Plugin::DefaultEnd>), which does what you usually need.
1122 However there are times when you need to add a bit to it, but don't want
1123 to write your own C<end> action.
1125 You can extend it like this:
1127 To add something to an C<end> action that is called before rendering
1128 (this is likely to be what you want), simply place it in the C<end>
1131 sub end : ActionClass('RenderView') {
1132 my ( $self, $c ) = @_;
1133 # do stuff here; the RenderView action is called afterwards
1136 To add things to an C<end> action that are called I<after> rendering,
1137 you can set it up like this:
1139 sub render : ActionClass('RenderView') { }
1142 my ( $self, $c ) = @_;
1143 $c->forward('render');
1151 A Catalyst application is driven by one or more Controller
1152 modules. There are a number of ways that Catalyst can decide which of
1153 the methods in your controller modules it should call. Controller
1154 methods are also called actions, because they determine how your
1155 catalyst application should (re-)act to any given URL. When the
1156 application is started up, catalyst looks at all your actions, and
1157 decides which URLs they map to.
1159 =head3 Type attributes
1161 Each action is a normal method in your controller, except that it has an
1162 L<attribute|http://search.cpan.org/~nwclark/perl-5.8.7/lib/attributes.pm>
1163 attached. These can be one of several types.
1165 Assume our Controller module starts with the following package declaration:
1167 package MyApp::Controller::Buckets;
1169 and we are running our application on localhost, port 3000 (the test
1176 A Path attribute also takes an argument, this can be either a relative
1177 or an absolute path. A relative path will be relative to the
1178 controller namespace, an absolute path will represent an exact
1181 sub my_handles : Path('handles') { .. }
1185 http://localhost:3000/buckets/handles
1189 sub my_handles : Path('/handles') { .. }
1193 http://localhost:3000/handles
1197 When using a Local attribute, no parameters are needed, instead, the
1198 name of the action is matched in the URL. The namespaces created by
1199 the name of the controller package is always part of the URL.
1201 sub my_handles : Local { .. }
1205 http://localhost:3000/buckets/my_handles
1209 A Global attribute is similar to a Local attribute, except that the
1210 namespace of the controller is ignored, and matching starts at root.
1212 sub my_handles : Global { .. }
1216 http://localhost:3000/my_handles
1220 By now you should have figured that a Regex attribute is just what it
1221 sounds like. This one takes a regular expression, and matches starting
1222 from root. These differ from the rest as they can match multiple URLs.
1224 sub my_handles : Regex('^handles') { .. }
1228 http://localhost:3000/handles
1232 http://localhost:3000/handles_and_other_parts
1238 A LocalRegex is similar to a Regex, except it only matches below the current
1239 controller namespace.
1241 sub my_handles : LocalRegex(^handles') { .. }
1245 http://localhost:3000/buckets/handles
1249 http://localhost:3000/buckets/handles_and_other_parts
1255 Last but not least, there is the Private attribute, which allows you
1256 to create your own internal actions, which can be forwarded to, but
1257 won't be matched as URLs.
1259 sub my_handles : Private { .. }
1261 becomes nothing at all..
1263 Catalyst also predefines some special Private actions, which you can
1264 override, these are:
1270 The default action will be called, if no other matching action is
1271 found. If you don't have one of these in your namespace, or any sub
1272 part of your namespace, you'll get an error page instead. If you want
1273 to find out where it was the user was trying to go, you can look in
1274 the request object using C<< $c->req->path >>.
1276 sub default : Private { .. }
1278 works for all unknown URLs, in this controller namespace, or every one
1279 if put directly into MyApp.pm.
1283 The index action is called when someone tries to visit the exact
1284 namespace of your controller. If index, default and matching Path
1285 actions are defined, then index will be used instead of default and
1288 sub index : Private { .. }
1292 http://localhost:3000/buckets
1296 The begin action is called at the beginning of every request involving
1297 this namespace directly, before other matching actions are called. It
1298 can be used to set up variables/data for this particular part of your
1299 app. A single begin action is called, its always the one most relevant
1300 to the current namespace.
1302 sub begin : Private { .. }
1306 http://localhost:3000/bucket/(anything)?
1312 Like begin, this action is always called for the namespace it is in,
1313 after every other action has finished. It is commonly used to forward
1314 processing to the View component. A single end action is called, its
1315 always the one most relevant to the current namespace.
1318 sub end : Private { .. }
1320 is called once after any actions when
1322 http://localhost:3000/bucket/(anything)?
1328 Lastly, the auto action is magic in that B<every> auto action in the
1329 chain of paths up to and including the ending namespace, will be
1330 called. (In contrast, only one of the begin/end/default actions will
1331 be called, the relevant one).
1334 sub auto : Private { .. }
1338 sub auto : Private { .. }
1340 will both be called when visiting
1342 http://localhost:3000/bucket/(anything)?
1348 =head3 A word of warning
1350 Due to possible namespace conflicts with Plugins, it is advised to
1351 only put the pre-defined Private actions in your main MyApp.pm file,
1352 all others should go in a Controller module.
1354 =head3 More Information
1356 L<http://search.cpan.org/author/SRI/Catalyst-5.61/lib/Catalyst/Manual/Intro.pod>
1358 L<http://dev.catalyst.perl.org/wiki/FlowChart>
1360 =head2 Component-based Subrequests
1362 See L<Catalyst::Plugin::SubRequest>.
1366 =head3 Single file upload with Catalyst
1368 To implement uploads in Catalyst, you need to have a HTML form similar to
1371 <form action="/upload" method="post" enctype="multipart/form-data">
1372 <input type="hidden" name="form_submit" value="yes">
1373 <input type="file" name="my_file">
1374 <input type="submit" value="Send">
1377 It's very important not to forget C<enctype="multipart/form-data"> in
1380 Catalyst Controller module 'upload' action:
1382 sub upload : Global {
1383 my ($self, $c) = @_;
1385 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1387 if ( my $upload = $c->request->upload('my_file') ) {
1389 my $filename = $upload->filename;
1390 my $target = "/tmp/upload/$filename";
1392 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1393 die( "Failed to copy '$filename' to '$target': $!" );
1398 $c->stash->{template} = 'file_upload.html';
1401 =head3 Multiple file upload with Catalyst
1403 Code for uploading multiple files from one form needs a few changes:
1405 The form should have this basic structure:
1407 <form action="/upload" method="post" enctype="multipart/form-data">
1408 <input type="hidden" name="form_submit" value="yes">
1409 <input type="file" name="file1" size="50"><br>
1410 <input type="file" name="file2" size="50"><br>
1411 <input type="file" name="file3" size="50"><br>
1412 <input type="submit" value="Send">
1415 And in the controller:
1417 sub upload : Local {
1418 my ($self, $c) = @_;
1420 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1422 for my $field ( $c->req->upload ) {
1424 my $upload = $c->req->upload($field);
1425 my $filename = $upload->filename;
1426 my $target = "/tmp/upload/$filename";
1428 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1429 die( "Failed to copy '$filename' to '$target': $!" );
1434 $c->stash->{template} = 'file_upload.html';
1437 C<for my $field ($c-E<gt>req->upload)> loops automatically over all file
1438 input fields and gets input names. After that is basic file saving code,
1439 just like in single file upload.
1441 Notice: C<die>ing might not be what you want to do, when an error
1442 occurs, but it works as an example. A better idea would be to store
1443 error C<$!> in $c->stash->{error} and show a custom error template
1444 displaying this message.
1446 For more information about uploads and usable methods look at
1447 L<Catalyst::Request::Upload> and L<Catalyst::Request>.
1449 =head2 Forwarding with arguments
1451 Sometimes you want to pass along arguments when forwarding to another
1452 action. As of version 5.30, arguments can be passed in the call to
1453 C<forward>; in earlier versions, you can manually set the arguments in
1454 the Catalyst Request object:
1456 # version 5.30 and later:
1457 $c->forward('/wherever', [qw/arg1 arg2 arg3/]);
1460 $c->req->args([qw/arg1 arg2 arg3/]);
1461 $c->forward('/wherever');
1463 (See the L<Catalyst::Manual::Intro> Flow_Control section for more
1464 information on passing arguments via C<forward>.)
1469 The recipes below describe aspects of the deployment process,
1470 including web server engines and tips to improve application efficiency.
1472 =head2 mod_perl Deployment
1474 mod_perl is the best solution for many applications, but we'll list some pros
1475 and cons so you can decide for yourself. The other production deployment
1476 option is FastCGI, for which see below.
1482 mod_perl is very fast and your app will benefit from being loaded in memory
1483 within each Apache process.
1485 =head4 Shared memory for multiple apps
1487 If you need to run several Catalyst apps on the same server, mod_perl will
1488 share the memory for common modules.
1494 Since your application is fully loaded in memory, every Apache process will
1495 be rather large. This means a large Apache process will be tied up while
1496 serving static files, large files, or dealing with slow clients. For this
1497 reason, it is best to run a two-tiered web architecture with a lightweight
1498 frontend server passing dynamic requests to a large backend mod_perl
1503 Any changes made to the core code of your app require a full Apache restart.
1504 Catalyst does not support Apache::Reload or StatINC. This is another good
1505 reason to run a frontend web server where you can set up an
1506 C<ErrorDocument 502> page to report that your app is down for maintenance.
1508 =head4 Cannot run multiple versions of the same app
1510 It is not possible to run two different versions of the same application in
1511 the same Apache instance because the namespaces will collide.
1515 Now that we have that out of the way, let's talk about setting up mod_perl
1516 to run a Catalyst app.
1518 =head4 1. Install Catalyst::Engine::Apache
1520 You should install the latest versions of both Catalyst and
1521 Catalyst::Engine::Apache. The Apache engines were separated from the
1522 Catalyst core in version 5.50 to allow for updates to the engine without
1523 requiring a new Catalyst release.
1525 =head4 2. Install Apache with mod_perl
1527 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
1528 recommended. With Apache 2, make sure you are using the prefork MPM and not
1529 the worker MPM. The reason for this is that many Perl modules are not
1530 thread-safe and may have problems running within the threaded worker
1531 environment. Catalyst is thread-safe however, so if you know what you're
1532 doing, you may be able to run using worker.
1534 In Debian, the following commands should get you going.
1536 apt-get install apache2-mpm-prefork
1537 apt-get install libapache2-mod-perl2
1539 =head4 3. Configure your application
1541 Every Catalyst application will automagically become a mod_perl handler
1542 when run within mod_perl. This makes the configuration extremely easy.
1543 Here is a basic Apache 2 configuration.
1545 PerlSwitches -I/var/www/MyApp/lib
1550 PerlResponseHandler MyApp
1553 The most important line here is C<PerlModule MyApp>. This causes mod_perl
1554 to preload your entire application into shared memory, including all of your
1555 controller, model, and view classes and configuration. If you have -Debug
1556 mode enabled, you will see the startup output scroll by when you first
1559 For an example Apache 1.3 configuration, please see the documentation for
1560 L<Catalyst::Engine::Apache::MP13>.
1564 That's it, your app is now a full-fledged mod_perl application! Try it out
1565 by going to http://your.server.com/.
1567 =head3 Other Options
1569 =head4 Non-root location
1571 You may not always want to run your app at the root of your server or virtual
1572 host. In this case, it's a simple change to run at any non-root location
1577 PerlResponseHandler MyApp
1580 When running this way, it is best to make use of the C<uri_for> method in
1581 Catalyst for constructing correct links.
1583 =head4 Static file handling
1585 Static files can be served directly by Apache for a performance boost.
1587 DocumentRoot /var/www/MyApp/root
1589 SetHandler default-handler
1592 This will let all files within root/static be handled directly by Apache. In
1593 a two-tiered setup, the frontend server should handle static files.
1594 The configuration to do this on the frontend will vary.
1596 The same is accomplished in lighttpd with the following snippet:
1598 $HTTP["url"] !~ "^/(?:img/|static/|css/|favicon.ico$)" {
1602 "socket" => "/tmp/myapp.socket",
1603 "check-local" => "disable",
1609 Which serves everything in the img, static, css directories
1610 statically, as well as the favicon file.
1612 Note the path of the application needs to be stated explicitly in the
1613 web server configuration for both these recipes.
1615 =head2 Catalyst on shared hosting
1617 So, you want to put your Catalyst app out there for the whole world to
1618 see, but you don't want to break the bank. There is an answer - if you
1619 can get shared hosting with FastCGI and a shell, you can install your
1620 Catalyst app in a local directory on your shared host. First, run
1622 perl -MCPAN -e shell
1624 and go through the standard CPAN configuration process. Then exit out
1625 without installing anything. Next, open your .bashrc and add
1627 export PATH=$HOME/local/bin:$HOME/local/script:$PATH
1628 perlversion=`perl -v | grep 'built for' | awk '{print $4}' | sed -e 's/v//;'`
1629 export PERL5LIB=$HOME/local/share/perl/$perlversion:$HOME/local/lib/perl/$perlversion:$HOME/local/lib:$PERL5LIB
1631 and log out, then back in again (or run C<". .bashrc"> if you
1632 prefer). Finally, edit C<.cpan/CPAN/MyConfig.pm> and add
1634 'make_install_arg' => qq[SITEPREFIX=$ENV{HOME}/local],
1635 'makepl_arg' => qq[INSTALLDIRS=site install_base=$ENV{HOME}/local],
1637 Now you can install the modules you need using CPAN as normal; they
1638 will be installed into your local directory, and perl will pick them
1639 up. Finally, change directory into the root of your virtual host and
1640 symlink your application's script directory in:
1642 cd path/to/mydomain.com
1643 ln -s ~/lib/MyApp/script script
1645 And add the following lines to your .htaccess file (assuming the server
1646 is setup to handle .pl as fcgi - you may need to rename the script to
1647 myapp_fastcgi.fcgi and/or use a SetHandler directive):
1650 RewriteCond %{REQUEST_URI} !^/?script/myapp_fastcgi.pl
1651 RewriteRule ^(.*)$ script/myapp_fastcgi.pl/$1 [PT,L]
1653 Now C<http://mydomain.com/> should now Just Work. Congratulations, now
1654 you can tell your friends about your new website (or in our case, tell
1655 the client it's time to pay the invoice :) )
1657 =head2 FastCGI Deployment
1659 FastCGI is a high-performance extension to CGI. It is suitable
1660 for production environments.
1666 FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you;
1667 your app runs as multiple persistent processes ready to receive connections
1668 from the web server.
1672 When using external FastCGI servers, your application runs as a standalone
1673 application server. It may be restarted independently from the web server.
1674 This allows for a more robust environment and faster reload times when
1675 pushing new app changes. The frontend server can even be configured to
1676 display a friendly "down for maintenance" page while the application is
1679 =head4 Load-balancing
1681 You can launch your application on multiple backend servers and allow the
1682 frontend web server to load-balance between all of them. And of course, if
1683 one goes down, your app continues to run fine.
1685 =head4 Multiple versions of the same app
1687 Each FastCGI application is a separate process, so you can run different
1688 versions of the same app on a single server.
1690 =head4 Can run with threaded Apache
1692 Since your app is not running inside of Apache, the faster mpm_worker module
1693 can be used without worrying about the thread safety of your application.
1697 =head4 More complex environment
1699 With FastCGI, there are more things to monitor and more processes running
1700 than when using mod_perl.
1704 =head4 1. Install Apache with mod_fastcgi
1706 mod_fastcgi for Apache is a third party module, and can be found at
1707 L<http://www.fastcgi.com/>. It is also packaged in many distributions,
1708 for example, libapache2-mod-fastcgi in Debian.
1710 =head4 2. Configure your application
1712 # Serve static content directly
1713 DocumentRoot /var/www/MyApp/root
1714 Alias /static /var/www/MyApp/root/static
1716 FastCgiServer /var/www/MyApp/script/myapp_fastcgi.pl -processes 3
1717 Alias /myapp/ /var/www/MyApp/script/myapp_fastcgi.pl/
1719 # Or, run at the root
1720 Alias / /var/www/MyApp/script/myapp_fastcgi.pl/
1722 The above commands will launch 3 app processes and make the app available at
1725 =head3 Standalone server mode
1727 While not as easy as the previous method, running your app as an external
1728 server gives you much more flexibility.
1730 First, launch your app as a standalone server listening on a socket.
1732 script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5 -p /tmp/myapp.pid -d
1734 You can also listen on a TCP port if your web server is not on the same
1737 script/myapp_fastcgi.pl -l :8080 -n 5 -p /tmp/myapp.pid -d
1739 You will probably want to write an init script to handle starting/stopping
1740 of the app using the pid file.
1742 Now, we simply configure Apache to connect to the running server.
1744 # 502 is a Bad Gateway error, and will occur if the backend server is down
1745 # This allows us to display a friendly static page that says "down for
1747 Alias /_errors /var/www/MyApp/root/error-pages
1748 ErrorDocument 502 /_errors/502.html
1750 FastCgiExternalServer /tmp/myapp.fcgi -socket /tmp/myapp.socket
1751 Alias /myapp/ /tmp/myapp.fcgi/
1753 # Or, run at the root
1754 Alias / /tmp/myapp.fcgi/
1758 L<Catalyst::Engine::FastCGI>.
1760 =head2 Development server deployment
1762 The development server is a mini web server written in perl. If you
1763 expect a low number of hits or you don't need mod_perl/FastCGI speed,
1764 you could use the development server as the application server with a
1765 lightweight proxy web server at the front. However, consider using
1766 L<Catalyst::Engine::HTTP::POE> for this kind of deployment instead, since
1767 it can better handle multiple concurrent requests without forking, or can
1768 prefork a set number of servers for improved performance.
1772 As this is an application server setup, the pros are the same as
1773 FastCGI (with the exception of speed).
1778 The development server is what you create your code on, so if it works
1779 here, it should work in production!
1785 Not as fast as mod_perl or FastCGI. Needs to fork for each request
1786 that comes in - make sure static files are served by the web server to
1791 =head4 Start up the development server
1793 script/myapp_server.pl -p 8080 -k -f -pidfile=/tmp/myapp.pid
1795 You will probably want to write an init script to handle stop/starting
1796 the app using the pid file.
1798 =head4 Configuring Apache
1800 Make sure mod_proxy is enabled and add:
1802 # Serve static content directly
1803 DocumentRoot /var/www/MyApp/root
1804 Alias /static /var/www/MyApp/root/static
1811 ProxyPass / http://localhost:8080/
1812 ProxyPassReverse / http://localhost:8080/
1814 You can wrap the above within a VirtualHost container if you want
1815 different apps served on the same host.
1817 =head2 Quick deployment: Building PAR Packages
1819 You have an application running on your development box, but then you
1820 have to quickly move it to another one for
1821 demonstration/deployment/testing...
1823 PAR packages can save you from a lot of trouble here. They are usual Zip
1824 files that contain a blib tree; you can even include all prereqs and a
1825 perl interpreter by setting a few flags!
1827 =head3 Follow these few points to try it out!
1829 1. Install Catalyst and PAR 0.89 (or later)
1831 % perl -MCPAN -e 'install Catalyst'
1833 % perl -MCPAN -e 'install PAR'
1836 2. Create a application
1842 Recent versions of Catalyst (5.62 and up) include
1843 L<Module::Install::Catalyst>, which simplifies the process greatly. From the shell in your application directory:
1848 Congratulations! Your package "myapp.par" is ready, the following
1849 steps are just optional.
1851 3. Test your PAR package with "parl" (no typo)
1855 [parl] myapp[.par] [script] [arguments]
1858 parl myapp.par myapp_server.pl -r
1868 % parl myapp.par myapp_server.pl
1869 You can connect to your server at http://localhost:3000
1871 Yes, this nifty little starter application gets automatically included.
1872 You can also use "catalyst_par_script('myapp_server.pl')" to set a
1873 default script to execute.
1875 6. Want to create a binary that includes the Perl interpreter?
1877 % pp -o myapp myapp.par
1878 % ./myapp myapp_server.pl
1879 You can connect to your server at http://localhost:3000
1881 =head2 Serving static content
1883 Serving static content in Catalyst used to be somewhat tricky; the use
1884 of L<Catalyst::Plugin::Static::Simple> makes everything much easier.
1885 This plugin will automatically serve your static content during development,
1886 but allows you to easily switch to Apache (or other server) in a
1887 production environment.
1889 =head3 Introduction to Static::Simple
1891 Static::Simple is a plugin that will help to serve static content for your
1892 application. By default, it will serve most types of files, excluding some
1893 standard Template Toolkit extensions, out of your B<root> file directory. All
1894 files are served by path, so if B<images/me.jpg> is requested, then
1895 B<root/images/me.jpg> is found and served.
1899 Using the plugin is as simple as setting your use line in MyApp.pm to include:
1901 use Catalyst qw/Static::Simple/;
1903 and already files will be served.
1907 Static content is best served from a single directory within your root
1908 directory. Having many different directories such as C<root/css> and
1909 C<root/images> requires more code to manage, because you must separately
1910 identify each static directory--if you decide to add a C<root/js>
1911 directory, you'll need to change your code to account for it. In
1912 contrast, keeping all static directories as subdirectories of a main
1913 C<root/static> directory makes things much easier to manage. Here's an
1914 example of a typical root directory structure:
1918 root/controller/stuff.tt
1921 root/static/css/main.css
1922 root/static/images/logo.jpg
1923 root/static/js/code.js
1926 All static content lives under C<root/static>, with everything else being
1927 Template Toolkit files.
1933 You may of course want to change the default locations, and make
1934 Static::Simple look somewhere else, this is as easy as:
1936 MyApp->config->{static}->{include_path} = [
1937 MyApp->config->{root},
1941 When you override include_path, it will not automatically append the
1942 normal root path, so you need to add it yourself if you still want
1943 it. These will be searched in order given, and the first matching file
1946 =item Static directories
1948 If you want to force some directories to be only static, you can set
1949 them using paths relative to the root dir, or regular expressions:
1951 MyApp->config->{static}->{dirs} = [
1956 =item File extensions
1958 By default, the following extensions are not served (that is, they will
1959 be processed by Catalyst): B<tmpl, tt, tt2, html, xhtml>. This list can
1962 MyApp->config->{static}->{ignore_extensions} = [
1963 qw/tmpl tt tt2 html xhtml/
1966 =item Ignoring directories
1968 Entire directories can be ignored. If used with include_path,
1969 directories relative to the include_path dirs will also be ignored:
1971 MyApp->config->{static}->{ignore_dirs} = [ qw/tmpl css/ ];
1975 =head3 More information
1977 L<http://search.cpan.org/dist/Catalyst-Plugin-Static-Simple/>
1979 =head3 Serving manually with the Static plugin with HTTP::Daemon (myapp_server.pl)
1981 In some situations you might want to control things more directly,
1982 using L<Catalyst::Plugin::Static>.
1984 In your main application class (MyApp.pm), load the plugin:
1986 use Catalyst qw/-Debug FormValidator Static OtherPlugin/;
1988 You will also need to make sure your end method does I<not> forward
1989 static content to the view, perhaps like this:
1992 my ( $self, $c ) = @_;
1994 $c->forward( 'MyApp::View::TT' )
1995 unless ( $c->res->body || !$c->stash->{template} );
1998 This code will only forward to the view if a template has been
1999 previously defined by a controller and if there is not already data in
2000 C<$c-E<gt>res-E<gt>body>.
2002 Next, create a controller to handle requests for the /static path. Use
2003 the Helper to save time. This command will create a stub controller as
2004 C<lib/MyApp/Controller/Static.pm>.
2006 $ script/myapp_create.pl controller Static
2008 Edit the file and add the following methods:
2010 # serve all files under /static as static files
2011 sub default : Path('/static') {
2012 my ( $self, $c ) = @_;
2014 # Optional, allow the browser to cache the content
2015 $c->res->headers->header( 'Cache-Control' => 'max-age=86400' );
2017 $c->serve_static; # from Catalyst::Plugin::Static
2020 # also handle requests for /favicon.ico
2021 sub favicon : Path('/favicon.ico') {
2022 my ( $self, $c ) = @_;
2027 You can also define a different icon for the browser to use instead of
2028 favicon.ico by using this in your HTML header:
2030 <link rel="icon" href="/static/myapp.ico" type="image/x-icon" />
2032 =head3 Common problems with the Static plugin
2034 The Static plugin makes use of the C<shared-mime-info> package to
2035 automatically determine MIME types. This package is notoriously
2036 difficult to install, especially on win32 and OS X. For OS X the easiest
2037 path might be to install Fink, then use C<apt-get install
2038 shared-mime-info>. Restart the server, and everything should be fine.
2040 Make sure you are using the latest version (>= 0.16) for best
2041 results. If you are having errors serving CSS files, or if they get
2042 served as text/plain instead of text/css, you may have an outdated
2043 shared-mime-info version. You may also wish to simply use the following
2044 code in your Static controller:
2046 if ($c->req->path =~ /css$/i) {
2047 $c->serve_static( "text/css" );
2052 =head3 Serving Static Files with Apache
2054 When using Apache, you can bypass Catalyst and any Static
2055 plugins/controllers controller by intercepting requests for the
2056 C<root/static> path at the server level. All that is required is to
2057 define a DocumentRoot and add a separate Location block for your static
2058 content. Here is a complete config for this application under mod_perl
2062 use lib qw(/var/www/MyApp/lib);
2067 ServerName myapp.example.com
2068 DocumentRoot /var/www/MyApp/root
2070 SetHandler perl-script
2073 <LocationMatch "/(static|favicon.ico)">
2074 SetHandler default-handler
2078 And here's a simpler example that'll get you started:
2080 Alias /static/ "/my/static/files/"
2081 <Location "/static">
2087 Catalyst makes it easy to employ several different types of caching to
2088 speed up your applications.
2090 =head3 Cache Plugins
2092 There are three wrapper plugins around common CPAN cache modules:
2093 Cache::FastMmap, Cache::FileCache, and Cache::Memcached. These can be
2094 used to cache the result of slow operations.
2096 This very page you're viewing makes use of the FileCache plugin to cache the
2097 rendered XHTML version of the source POD document. This is an ideal
2098 application for a cache because the source document changes infrequently but
2099 may be viewed many times.
2101 use Catalyst qw/Cache::FileCache/;
2106 sub render_pod : Local {
2107 my ( self, $c ) = @_;
2109 # the cache is keyed on the filename and the modification time
2110 # to check for updates to the file.
2111 my $file = $c->path_to( 'root', '2005', '11.pod' );
2112 my $mtime = ( stat $file )->mtime;
2114 my $cached_pod = $c->cache->get("$file $mtime");
2115 if ( !$cached_pod ) {
2116 $cached_pod = do_slow_pod_rendering();
2117 # cache the result for 12 hours
2118 $c->cache->set( "$file $mtime", $cached_pod, '12h' );
2120 $c->stash->{pod} = $cached_pod;
2123 We could actually cache the result forever, but using a value such as 12 hours
2124 allows old entries to be automatically expired when they are no longer needed.
2128 Another method of caching is to cache the entire HTML page. While this is
2129 traditionally handled by a front-end proxy server like Squid, the Catalyst
2130 PageCache plugin makes it trivial to cache the entire output from
2131 frequently-used or slow actions.
2133 Many sites have a busy content-filled front page that might look something
2134 like this. It probably takes a while to process, and will do the exact same
2135 thing for every single user who views the page.
2137 sub front_page : Path('/') {
2138 my ( $self, $c ) = @_;
2140 $c->forward( 'get_news_articles' );
2141 $c->forward( 'build_lots_of_boxes' );
2142 $c->forward( 'more_slow_stuff' );
2144 $c->stash->{template} = 'index.tt';
2147 We can add the PageCache plugin to speed things up.
2149 use Catalyst qw/Cache::FileCache PageCache/;
2151 sub front_page : Path ('/') {
2152 my ( $self, $c ) = @_;
2154 $c->cache_page( 300 );
2156 # same processing as above
2159 Now the entire output of the front page, from <html> to </html>, will be
2160 cached for 5 minutes. After 5 minutes, the next request will rebuild the
2161 page and it will be re-cached.
2163 Note that the page cache is keyed on the page URI plus all parameters, so
2164 requests for / and /?foo=bar will result in different cache items. Also,
2165 only GET requests will be cached by the plugin.
2167 You can even get that front-end Squid proxy to help out by enabling HTTP
2168 headers for the cached page.
2170 MyApp->config->{page_cache}->{set_http_headers} = 1;
2172 This would now set the following headers so proxies and browsers may cache
2173 the content themselves.
2175 Cache-Control: max-age=($expire_time - time)
2176 Expires: $expire_time
2177 Last-Modified: $cache_created_time
2179 =head3 Template Caching
2181 Template Toolkit provides support for caching compiled versions of your
2182 templates. To enable this in Catalyst, use the following configuration.
2183 TT will cache compiled templates keyed on the file mtime, so changes will
2184 still be automatically detected.
2186 package MyApp::View::TT;
2190 use base 'Catalyst::View::TT';
2192 __PACKAGE__->config(
2193 COMPILE_DIR => '/tmp/template_cache',
2200 See the documentation for each cache plugin for more details and other
2201 available configuration options.
2203 L<Catalyst::Plugin::Cache::FastMmap>
2204 L<Catalyst::Plugin::Cache::FileCache>
2205 L<Catalyst::Plugin::Cache::Memcached>
2206 L<Catalyst::Plugin::PageCache>
2207 L<http://search.cpan.org/dist/Template-Toolkit/lib/Template/Manual/Config.pod#Caching_and_Compiling_Options>
2211 Testing is an integral part of the web application development
2212 process. Tests make multi developer teams easier to coordinate, and
2213 they help ensure that there are no nasty surprises after upgrades or
2218 Catalyst provides a convenient way of testing your application during
2219 development and before deployment in a real environment.
2221 C<Catalyst::Test> makes it possible to run the same tests both locally
2222 (without an external daemon) and against a remote server via HTTP.
2226 Let's examine a skeleton application's C<t/> directory:
2228 mundus:~/MyApp chansen$ ls -l t/
2230 -rw-r--r-- 1 chansen chansen 95 18 Dec 20:50 01app.t
2231 -rw-r--r-- 1 chansen chansen 190 18 Dec 20:50 02pod.t
2232 -rw-r--r-- 1 chansen chansen 213 18 Dec 20:50 03podcoverage.t
2238 Verifies that the application loads, compiles, and returns a successful
2243 Verifies that all POD is free from errors. Only executed if the C<TEST_POD>
2244 environment variable is true.
2246 =item C<03podcoverage.t>
2248 Verifies that all methods/functions have POD coverage. Only executed if the
2249 C<TEST_POD> environment variable is true.
2253 =head3 Creating tests
2255 mundus:~/MyApp chansen$ cat t/01app.t | perl -ne 'printf( "%2d %s", $., $_ )'
2256 1 use Test::More tests => 2;
2257 2 use_ok( Catalyst::Test, 'MyApp' );
2259 4 ok( request('/')->is_success );
2261 The first line declares how many tests we are going to run, in this case
2262 two. The second line tests and loads our application in test mode. The
2263 fourth line verifies that our application returns a successful response.
2265 C<Catalyst::Test> exports two functions, C<request> and C<get>. Each can
2266 take three different arguments:
2270 =item A string which is a relative or absolute URI.
2272 request('/my/path');
2273 request('http://www.host.com/my/path');
2275 =item An instance of C<URI>.
2277 request( URI->new('http://www.host.com/my/path') );
2279 =item An instance of C<HTTP::Request>.
2281 request( HTTP::Request->new( GET => 'http://www.host.com/my/path') );
2285 C<request> returns an instance of C<HTTP::Response> and C<get> returns the
2286 content (body) of the response.
2288 =head3 Running tests locally
2290 mundus:~/MyApp chansen$ CATALYST_DEBUG=0 TEST_POD=1 prove --lib lib/ t/
2291 t/01app............ok
2292 t/02pod............ok
2293 t/03podcoverage....ok
2294 All tests successful.
2295 Files=3, Tests=4, 2 wallclock secs ( 1.60 cusr + 0.36 csys = 1.96 CPU)
2297 C<CATALYST_DEBUG=0> ensures that debugging is off; if it's enabled you
2298 will see debug logs between tests.
2300 C<TEST_POD=1> enables POD checking and coverage.
2302 C<prove> A command-line tool that makes it easy to run tests. You can
2303 find out more about it from the links below.
2305 =head3 Running tests remotely
2307 mundus:~/MyApp chansen$ CATALYST_SERVER=http://localhost:3000/ prove --lib lib/ t/01app.t
2309 All tests successful.
2310 Files=1, Tests=2, 0 wallclock secs ( 0.40 cusr + 0.01 csys = 0.41 CPU)
2312 C<CATALYST_SERVER=http://localhost:3000/> is the absolute deployment URI of
2313 your application. In C<CGI> or C<FastCGI> it should be the host and path
2316 =head3 C<Test::WWW::Mechanize> and Catalyst
2318 Be sure to check out C<Test::WWW::Mechanize::Catalyst>. It makes it easy to
2319 test HTML, forms and links. A short example of usage:
2321 use Test::More tests => 6;
2322 use_ok( Test::WWW::Mechanize::Catalyst, 'MyApp' );
2324 my $mech = Test::WWW::Mechanize::Catalyst->new;
2325 $mech->get_ok("http://localhost/", 'Got index page');
2326 $mech->title_like( qr/^MyApp on Catalyst/, 'Got right index title' );
2327 ok( $mech->find_link( text_regex => qr/^Wiki/i ), 'Found link to Wiki' );
2328 ok( $mech->find_link( text_regex => qr/^Mailing-List/i ), 'Found link to Mailing-List' );
2329 ok( $mech->find_link( text_regex => qr/^IRC channel/i ), 'Found link to IRC channel' );
2331 =head3 Further Reading
2335 =item Catalyst::Test
2337 L<http://search.cpan.org/dist/Catalyst/lib/Catalyst/Test.pm>
2339 =item Test::WWW::Mechanize::Catalyst
2341 L<http://search.cpan.org/dist/Test-WWW-Mechanize-Catalyst/lib/Test/WWW/Mechanize/Catalyst.pm>
2343 =item Test::WWW::Mechanize
2345 L<http://search.cpan.org/dist/Test-WWW-Mechanize/Mechanize.pm>
2347 =item WWW::Mechanize
2349 L<http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm>
2351 =item LWP::UserAgent
2353 L<http://search.cpan.org/dist/libwww-perl/lib/LWP/UserAgent.pm>
2357 L<http://search.cpan.org/dist/libwww-perl/lib/HTML/Form.pm>
2361 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Message.pm>
2365 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request.pm>
2367 =item HTTP::Request::Common
2369 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request/Common.pm>
2371 =item HTTP::Response
2373 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Response.pm>
2377 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Status.pm>
2381 L<http://search.cpan.org/dist/URI/URI.pm>
2385 L<http://search.cpan.org/dist/Test-Simple/lib/Test/More.pm>
2389 L<http://search.cpan.org/dist/Test-Pod/Pod.pm>
2391 =item Test::Pod::Coverage
2393 L<http://search.cpan.org/dist/Test-Pod-Coverage/Coverage.pm>
2395 =item prove (Test::Harness)
2397 L<http://search.cpan.org/dist/Test-Harness/bin/prove>
2401 =head3 More Information
2403 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::Roles>
2404 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::ACL>
2408 Sebastian Riedel C<sri@oook.de>
2410 Danijel Milicevic C<me@danijel.de>
2412 Viljo Marrandi C<vilts@yahoo.com>
2414 Marcus Ramberg C<mramberg@cpan.org>
2416 Jesse Sheidlower C<jester@panix.com>
2418 Andy Grundman C<andy@hybridized.org>
2420 Chisel Wright C<pause@herlpacker.co.uk>
2422 Will Hawes C<info@whawes.co.uk>
2424 Gavin Henry C<ghenry@perl.me.uk>
2426 Kieren Diment C<kd@totaldatasolution.com>
2430 This document is free, you can redistribute it and/or modify it
2431 under the same terms as Perl itself.