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
115 use parent qw/Catalyst/;
118 Session::Store::FastMmap
119 Session::State::Cookie
123 ## Write data into the session
125 sub add_item : Local {
126 my ( $self, $c ) = @_;
128 my $item_id = $c->req->param("item");
130 push @{ $c->session->{items} }, $item_id;
134 ## A page later we retrieve the data from the session:
136 sub get_items : Local {
137 my ( $self, $c ) = @_;
139 $c->stash->{items_to_display} = $c->session->{items};
144 =head3 More information
146 L<http://search.cpan.org/dist/Catalyst-Plugin-Session>
148 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-Cookie>
150 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-URI>
152 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-FastMmap>
154 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-File>
156 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-DBI>
158 =head2 Configure your application
160 You configure your application with the C<config> method in your
161 application class. This can be hard-coded, or brought in from a
162 separate configuration file.
164 =head3 Using Config::General
166 L<Config::General|Config::General> is a method for creating flexible
167 and readable configuration files. It's a great way to keep your
168 Catalyst application configuration in one easy-to-understand location.
170 Now create C<myapp.conf> in your application home:
174 # session; perldoc Catalyst::Plugin::Session::FastMmap
178 storage /tmp/myapp.session
181 # emails; perldoc Catalyst::Plugin::Email
182 # this passes options as an array :(
186 This is equivalent to:
188 # configure base package
189 __PACKAGE__->config( name => MyApp );
190 # configure authentication
191 __PACKAGE__->config->{authentication} = {
192 user_class => 'MyApp::Model::MyDB::Customer',
196 __PACKAGE__->config->{session} = {
200 # configure email sending
201 __PACKAGE__->config->{email} = [qw/SMTP localhost/];
203 See also L<Config::General|Config::General>.
205 =head1 Skipping your VCS's directories
207 Catalyst uses Module::Pluggable to load Models, Views and Controllers.
208 Module::Pluggable will scan through all directories and load modules
209 it finds. Sometimes you might want to skip some of these directories,
210 for example when your version control system makes a subdirectory with
211 meta-information in every version-controlled directory. While
212 Catalyst skips subversion and CVS directories already, there are other
213 source control systems. Here is the configuration you need to add
214 their directories to the list to skip.
216 You can make catalyst skip these directories using the Catalyst config:
218 # Configure the application
221 setup_components => { except => qr/SCCS/ },
224 See the Module::Pluggable manual page for more information on B<except>
227 =head1 Users and Access Control
229 Most multiuser, and some single user web applications require that
230 users identify themselves, and the application is often required to
231 define those roles. The recipes below describe some ways of doing
234 =head2 Authentication (logging in)
236 This is extensively covered in other documentation; see in particular
237 L<Catalyst::Plugin::Authentication> and the Authentication chapter
238 of the Tutorial at L<Catalyst::Manual::Tutorial::Authorization>.
240 =head2 Pass-through login (and other actions)
242 An easy way of having assorted actions that occur during the processing
243 of a request that are orthogonal to its actual purpose - logins, silent
244 commands etc. Provide actions for these, but when they're required for
245 something else fill e.g. a form variable __login and have a sub begin
248 sub begin : Private {
250 foreach my $action (qw/login docommand foo bar whatever/) {
251 if ($c->req->params->{"__${action}"}) {
252 $c->forward($action);
258 =head2 Role-based Authorization
260 For more advanced access control, you may want to consider using role-based
261 authorization. This means you can assign different roles to each user, e.g.
262 "user", "admin", etc.
264 The C<login> and C<logout> methods and view template are exactly the same as
265 in the previous example.
267 The L<Catalyst::Plugin::Authorization::Roles> plugin is required when
270 use parent qw/Catalyst/;
273 Authentication::Credential::Password
274 Authentication::Store::Htpasswd
275 Authorization::Roles/;
277 Roles are implemented automatically when using
278 L<Catalyst::Authentication::Store::Htpasswd>:
280 # no additional role configuration required
281 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
283 Or can be set up manually when using L<Catalyst::Authentication::Store::DBIC>:
285 # Authorization using a many-to-many role relationship
286 __PACKAGE__->config->{authorization}{dbic} = {
287 'role_class' => 'My::Model::DBIC::Role',
288 'role_field' => 'name',
289 'user_role_user_field' => 'user',
291 # DBIx::Class only (omit if using Class::DBI)
292 'role_rel' => 'user_role',
294 # Class::DBI only, (omit if using DBIx::Class)
295 'user_role_class' => 'My::Model::CDBI::UserRole'
296 'user_role_role_field' => 'role',
299 To restrict access to any action, you can use the C<check_user_roles> method:
301 sub restricted : Local {
302 my ( $self, $c ) = @_;
304 $c->detach("unauthorized")
305 unless $c->check_user_roles( "admin" );
307 # do something restricted here
310 You can also use the C<assert_user_roles> method. This just gives an
311 error if the current user does not have one of the required roles:
313 sub also_restricted : Global {
314 my ( $self, $c ) = @_;
315 $c->assert_user_roles( qw/ user admin / );
318 =head2 Authentication/Authorization
320 This is done in several steps:
326 Getting the user to identify themselves, by giving you some piece of
327 information known only to you and the user. Then you can assume that
328 the user is who they say they are. This is called B<credential
333 Making sure the user only accesses functions you want them to
334 access. This is done by checking the verified users data against your
335 internal list of groups, or allowed persons for the current page.
341 The Catalyst Authentication system is made up of many interacting
342 modules, to give you the most flexibility possible.
344 =head4 Credential verifiers
346 A Credential module tables the user input, and passes it to a Store,
347 or some other system, for verification. Typically, a user object is
348 created by either this module or the Store and made accessible by a
349 C<< $c->user >> call.
353 Password - Simple username/password checking.
354 HTTPD - Checks using basic HTTP auth.
355 TypeKey - Check using the typekey system.
357 =head3 Storage backends
359 A Storage backend contains the actual data representing the users. It
360 is queried by the credential verifiers. Updating the store is not done
361 within this system, you will need to do it yourself.
365 DBIC - Storage using a database.
366 Minimal - Storage using a simple hash (for testing).
370 A User object is created by either the storage backend or the
371 credential verifier, and filled with the retrieved user information.
375 Hash - A simple hash of keys and values.
377 =head3 ACL authorization
379 ACL stands for Access Control List. The ACL plugin allows you to
380 regulate access on a path by path basis, by listing which users, or
381 roles, have access to which paths.
383 =head3 Roles authorization
385 Authorization by roles is for assigning users to groups, which can
386 then be assigned to ACLs, or just checked when needed.
390 When you have chosen your modules, all you need to do is call the C<<
391 $c->login >> method. If called with no parameters, it will try to find
392 suitable parameters, such as B<username> and B<password>, or you can
393 pass it these values.
395 =head3 Checking roles
397 Role checking is done by using the C<< $c->check_user_roles >> method,
398 this will check using the currently logged in user (via C<< $c->user
399 >>). You pass it the name of a role to check, and it returns true if
400 the user is a member.
404 use parent qw/Catalyst/;
405 use Catalyst qw/Authentication
406 Authentication::Credential::Password
407 Authentication::Store::Htpasswd
408 Authorization::Roles/;
410 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
415 if ( my $user = $c->req->param("user")
416 and my $password = $c->req->param("password") )
418 if ( $c->login( $user, $password ) ) {
419 $c->res->body( "hello " . $c->user->name );
429 sub restricted : Local {
430 my ( $self, $c ) = @_;
432 $c->detach("unauthorized")
433 unless $c->check_user_roles( "admin" );
435 # do something restricted here
438 =head3 Using authentication in a testing environment
440 Ideally, to write tests for authentication/authorization code one
441 would first set up a test database with known data, then use
442 L<Test::WWW::Mechanize::Catalyst> to simulate a user logging
443 in. Unfortunately the former can be rather awkward, which is why it's
444 a good thing that the authentication framework is so flexible.
446 Instead of using a test database, one can simply change the
447 authentication store to something a bit easier to deal with in a
448 testing environment. Additionally, this has the advantage of not
449 modifying one's database, which can be problematic if one forgets to
450 use the testing instead of production database.
454 use Catalyst::Plugin::Authentication::Store::Minimal::Backend;
456 # Sets up the user `test_user' with password `test_pass'
457 MyApp->default_auth_store(
458 Catalyst::Plugin::Authentication::Store::Minimal::Backend->new({
459 test_user => { password => 'test_pass' },
463 Now, your test code can call C<$c->login('test_user', 'test_pass')> and
464 successfully login, without messing with the database at all.
466 =head3 More information
468 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authentication> has a longer explanation.
474 Authorization is the step that comes after
475 authentication. Authentication establishes that the user agent is
476 really representing the user we think it's representing, and then
477 authorization determines what this user is allowed to do.
479 =head3 Role Based Access Control
481 Under role based access control each user is allowed to perform any
482 number of roles. For example, at a zoo no one but specially trained
483 personnel can enter the moose cage (Mynd you, møøse bites kan be
484 pretty nasti!). For example:
486 package Zoo::Controller::MooseCage;
488 sub feed_moose : Local {
489 my ( $self, $c ) = @_;
491 $c->model( "Moose" )->eat( $c->req->param("food") );
494 With this action, anyone can just come into the moose cage and feed
495 the moose, which is a very dangerous thing. We need to restrict this
496 action, so that only a qualified moose feeder can perform that action.
498 The Authorization::Roles plugin let's us perform role based access
499 control checks. Let's load it:
501 use parent qw/Catalyst/;
503 Authentication # yadda yadda
507 And now our action should look like this:
509 sub feed_moose : Local {
510 my ( $self, $c ) = @_;
512 if ( $c->check_roles( "moose_feeder" ) ) {
513 $c->model( "Moose" )->eat( $c->req->param("food") );
515 $c->stash->{error} = "unauthorized";
519 This checks C<< $c->user >>, and only if the user has B<all> the roles
520 in the list, a true value is returned.
522 C<check_roles> has a sister method, C<assert_roles>, which throws an
523 exception if any roles are missing.
525 Some roles that might actually make sense in, say, a forum application:
539 each with a distinct task (system administration versus content
542 =head3 Access Control Lists
544 Checking for roles all the time can be tedious and error prone.
546 The Authorization::ACL plugin let's us declare where we'd like checks
547 to be done automatically for us.
549 For example, we may want to completely block out anyone who isn't a
550 C<moose_feeder> from the entire C<MooseCage> controller:
552 Zoo->deny_access_unless( "/moose_cage", [qw/moose_feeder/] );
554 The role list behaves in the same way as C<check_roles>. However, the
555 ACL plugin isn't limited to just interacting with the Roles plugin. We
556 can use a code reference instead. For example, to allow either moose
557 trainers or moose feeders into the moose cage, we can create a more
560 Zoo->deny_access_unless( "/moose_cage", sub {
562 $c->check_roles( "moose_trainer" ) || $c->check_roles( "moose_feeder" );
565 The more specific a role, the earlier it will be checked. Let's say
566 moose feeders are now restricted to only the C<feed_moose> action,
567 while moose trainers get access everywhere:
569 Zoo->deny_access_unless( "/moose_cage", [qw/moose_trainer/] );
570 Zoo->allow_access_if( "/moose_cage/feed_moose", [qw/moose_feeder/]);
572 When the C<feed_moose> action is accessed the second check will be
573 made. If the user is a C<moose_feeder>, then access will be
574 immediately granted. Otherwise, the next rule in line will be tested -
575 the one checking for a C<moose_trainer>. If this rule is not
576 satisfied, access will be immediately denied.
578 Rules applied to the same path will be checked in the order they were
581 Lastly, handling access denial events is done by creating an
582 C<access_denied> private action:
584 sub access_denied : Private {
585 my ( $self, $c, $action ) = @_;
588 This action works much like auto, in that it is inherited across
589 namespaces (not like object oriented code). This means that the
590 C<access_denied> action which is B<nearest> to the action which was
591 blocked will be triggered.
593 If this action does not exist, an error will be thrown, which you can
594 clean up in your C<end> private action instead.
596 Also, it's important to note that if you restrict access to "/" then
597 C<end>, C<default>, etc will also be restricted.
599 MyApp->acl_allow_root_internals;
601 will create rules that permit access to C<end>, C<begin>, and C<auto> in the
602 root of your app (but not in any other controller).
606 Models are where application data belongs. Catalyst is exteremely
607 flexible with the kind of models that it can use. The recipes here
610 =head2 Using existing DBIC (etc.) classes with Catalyst
612 Many people have existing Model classes that they would like to use
613 with Catalyst (or, conversely, they want to write Catalyst models that
614 can be used outside of Catalyst, e.g. in a cron job). It's trivial to
615 write a simple component in Catalyst that slurps in an outside Model:
617 package MyApp::Model::DB;
618 use base qw/Catalyst::Model::DBIC::Schema/;
620 schema_class => 'Some::DBIC::Schema',
621 connect_info => ['dbi:SQLite:foo.db', '', '', {AutoCommit=>1}];
625 and that's it! Now C<Some::DBIC::Schema> is part of your
626 Cat app as C<MyApp::Model::DB>.
628 =head2 DBIx::Class as a Catalyst Model
630 See L<Catalyst::Model::DBIC::Schema>.
632 =head2 Create accessors to preload static data once per server instance
634 When you have data that you want to load just once from the model at
635 server load instead of for each request, use mk_group_accessors to
636 create accessors and tie them to resultsets in your package that
637 inherits from DBIx::Class::Schema
640 use base qw/DBIx::Class::Schema/;
641 __PACKAGE__->register_class('RESULTSOURCEMONIKER',
642 'My::Schema::RESULTSOURCE');
643 __PACKAGE__->mk_group_accessors('simple' =>
644 qw(ACCESSORNAME1 ACCESSORNAME2 ACCESSORNAMEn));
647 my ($self, @rest) = @_;
648 $self->next::method(@rest);
649 # $self is now a live My::Schema object, complete with DB connection
651 $self->ACCESSORNAME1([ $self->resultset('RESULTSOURCEMONIKER')->all ]);
652 $self->ACCESSORNAME2([ $self->resultset('RESULTSOURCEMONIKER')->search({ COLUMN => { '<' => '30' } })->all ]);
653 $self->ACCESSORNAMEn([ $self->resultset('RESULTSOURCEMONIKER')->find(1) ]);
658 and now in the controller, you can now access any of these without a
661 $c->stash->{something} = $c->model('My::Schema')->schema->ACCESSORNAMEn;
666 Unlike SOAP, XMLRPC is a very simple (and imo elegant) web-services
667 protocol, exchanging small XML messages like these:
672 TE: deflate,gzip;q=0.3
673 Connection: TE, close
677 User-Agent: SOAP::Lite/Perl/0.60
679 Content-Type: text/xml
681 <?xml version="1.0" encoding="UTF-8"?>
683 <methodName>add</methodName>
685 <param><value><int>1</int></value></param>
686 <param><value><int>2</int></value></param>
693 Date: Tue, 20 Dec 2005 07:45:55 GMT
695 Content-Type: text/xml
699 <?xml version="1.0" encoding="us-ascii"?>
702 <param><value><int>3</int></value></param>
706 Now follow these few steps to implement the application:
708 1. Install Catalyst (5.61 or later), Catalyst::Plugin::XMLRPC (0.06 or
709 later) and SOAP::Lite (for XMLRPCsh.pl).
711 2. Create an application framework:
717 3. Add the XMLRPC plugin to MyApp.pm
719 use Catalyst qw/-Debug Static::Simple XMLRPC/;
721 4. Add an API controller
723 % ./script/myapp_create.pl controller API
725 5. Add a XMLRPC redispatch method and an add method with Remote
726 attribute to lib/MyApp/Controller/API.pm
729 my ( $self, $c ) = @_;
734 my ( $self, $c, $a, $b ) = @_;
738 The default action is the entry point for each XMLRPC request. It will
739 redispatch every request to methods with Remote attribute in the same
742 The C<add> method is not a traditional action; it has no private or
743 public path. Only the XMLRPC dispatcher knows it exists.
745 6. That's it! You have built your first web service. Let's test it with
746 XMLRPCsh.pl (part of SOAP::Lite):
748 % ./script/myapp_server.pl
750 % XMLRPCsh.pl http://127.0.0.1:3000/api
751 Usage: method[(parameters)]
753 --- XMLRPC RESULT ---
758 Your return data type is usually auto-detected, but you can easily
759 enforce a specific one.
762 my ( $self, $c, $a, $b ) = @_;
763 return RPC::XML::int->new( $a + $b );
770 Views pertain to the display of your application. As with models,
771 catalyst is uncommonly flexible. The recipes below are just a start.
773 =head2 Catalyst::View::TT
775 One of the first things you probably want to do when starting a new
776 Catalyst application is set up your View. Catalyst doesn't care how you
777 display your data; you can choose to generate HTML, PDF files, or plain
780 Most Catalyst applications use a template system to generate their HTML,
781 and though there are several template systems available, Template
782 Toolkit is probably the most popular.
784 Once again, the Catalyst developers have done all the hard work, and
785 made things easy for the rest of us. Catalyst::View::TT provides the
786 interface to Template Toolkit, and provides Helpers which let us set it
787 up that much more easily.
789 =head3 Creating your View
791 Catalyst::View::TT provides two different helpers for us to use: TT and
796 Create a basic Template Toolkit View using the provided helper script:
798 script/myapp_create.pl view TT TT
800 This will create lib/MyApp/View/MyView.pm, which is going to be pretty
801 empty to start. However, it sets everything up that you need to get
802 started. You can now define which template you want and forward to your
806 my ( $self, $c ) = @_;
808 $c->stash->{template} = 'hello.tt';
810 $c->forward( $c->view('TT') );
813 In practice you wouldn't do the forwarding manually, but would
814 use L<Catalyst::Action::RenderView>.
818 Although the TT helper does create a functional, working view, you may
819 find yourself having to create the same template files and changing the
820 same options every time you create a new application. The TTSite helper
821 saves us even more time by creating the basic templates and setting some
822 common options for us.
824 Once again, you can use the helper script:
826 script/myapp_create.pl view TT TTSite
828 This time, the helper sets several options for us in the generated View.
830 __PACKAGE__->config({
831 CATALYST_VAR => 'Catalyst',
833 MyApp->path_to( 'root', 'src' ),
834 MyApp->path_to( 'root', 'lib' )
836 PRE_PROCESS => 'config/main',
837 WRAPPER => 'site/wrapper',
838 ERROR => 'error.tt2',
846 INCLUDE_PATH defines the directories that Template Toolkit should search
847 for the template files.
851 PRE_PROCESS is used to process configuration options which are common to
856 WRAPPER is a file which is processed with each template, usually used to
857 easily provide a common header and footer for every page.
861 In addition to setting these options, the TTSite helper also created the
862 template and config files for us! In the 'root' directory, you'll notice
863 two new directories: src and lib.
865 Several configuration files in root/lib/config are called by PRE_PROCESS.
867 The files in root/lib/site are the site-wide templates, called by
868 WRAPPER, and display the html framework, control the layout, and provide
869 the templates for the header and footer of your page. Using the template
870 organization provided makes it much easier to standardize pages and make
871 changes when they are (inevitably) needed.
873 The template files that you will create for your application will go
874 into root/src, and you don't need to worry about putting the the <html>
875 or <head> sections; just put in the content. The WRAPPER will the rest
876 of the page around your template for you.
881 Of course, having the template system include the header and footer for
882 you isn't all that we want our templates to do. We need to be able to
883 put data into our templates, and have it appear where and how we want
884 it, right? That's where the stash comes in.
886 In our controllers, we can add data to the stash, and then access it
887 from the template. For instance:
890 my ( $self, $c ) = @_;
892 $c->stash->{name} = 'Adam';
894 $c->stash->{template} = 'hello.tt';
896 $c->forward( $c->view('TT') );
901 <strong>Hello, [% name %]!</strong>
903 When you view this page, it will display "Hello, Adam!"
905 All of the information in your stash is available, by its name/key, in
906 your templates. And your data don't have to be plain, old, boring
907 scalars. You can pass array references and hash references, too.
912 my ( $self, $c ) = @_;
914 $c->stash->{names} = [ 'Adam', 'Dave', 'John' ];
916 $c->stash->{template} = 'hello.tt';
918 $c->forward( $c->view('TT') );
923 [% FOREACH name IN names %]
924 <strong>Hello, [% name %]!</strong><br />
927 This allowed us to loop through each item in the arrayref, and display a
928 line for each name that we have.
930 This is the most basic usage, but Template Toolkit is quite powerful,
931 and allows you to truly keep your presentation logic separate from the
932 rest of your application.
936 One of my favorite things about Catalyst is the ability to move an
937 application around without having to worry that everything is going to
938 break. One of the areas that used to be a problem was with the http
939 links in your template files. For example, suppose you have an
940 application installed at http://www.domain.com/Calendar. The links point
941 to "/Calendar", "/Calendar/2005", "/Calendar/2005/10", etc. If you move
942 the application to be at http://www.mydomain.com/Tools/Calendar, then
943 all of those links will suddenly break.
945 That's where $c->uri_for() comes in. This function will merge its
946 parameters with either the base location for the app, or its current
947 namespace. Let's take a look at a couple of examples.
949 In your template, you can use the following:
951 <a href="[% c.uri_for('/login') %]">Login Here</a>
953 Although the parameter starts with a forward slash, this is relative
954 to the application root, not the webserver root. This is important to
955 remember. So, if your application is installed at
956 http://www.domain.com/Calendar, then the link would be
957 http://www.mydomain.com/Calendar/Login. If you move your application
958 to a different domain or path, then that link will still be correct.
962 <a href="[% c.uri_for('2005','10', '24') %]">October, 24 2005</a>
964 The first parameter does NOT have a forward slash, and so it will be
965 relative to the current namespace. If the application is installed at
966 http://www.domain.com/Calendar. and if the template is called from
967 MyApp::Controller::Display, then the link would become
968 http://www.domain.com/Calendar/Display/2005/10/24.
970 If you want to link to a parent uri of your current namespace you can
971 prefix the arguments with multiple '../':
973 <a href="[% c.uri_for('../../view', stashed_object.id) %]">User view</a>
975 Once again, this allows you to move your application around without
976 having to worry about broken links. But there's something else, as
977 well. Since the links are generated by uri_for, you can use the same
978 template file by several different controllers, and each controller
979 will get the links that its supposed to. Since we believe in Don't
980 Repeat Yourself, this is particularly helpful if you have common
981 elements in your site that you want to keep in one file.
985 L<http://search.cpan.org/perldoc?Catalyst>
987 L<http://search.cpan.org/perldoc?Catalyst%3A%3AView%3A%3ATT>
989 L<http://search.cpan.org/perldoc?Template>
991 =head2 Adding RSS feeds
993 Adding RSS feeds to your Catalyst applications is simple. We'll see two
994 different aproaches here, but the basic premise is that you forward to
995 the normal view action first to get the objects, then handle the output
998 =head3 Using TT templates
1000 This is the aproach used in Agave (L<http://dev.rawmode.org/>).
1004 $c->forward('view');
1005 $c->stash->{template}='rss.tt';
1008 Then you need a template. Here's the one from Agave:
1010 <?xml version="1.0" encoding="UTF-8"?>
1011 <rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/">
1013 <title>[ [% blog.name || c.config.name || "Agave" %] ] RSS Feed</title>
1014 <link>[% base %]</link>
1015 <description>Recent posts</description>
1016 <language>en-us</language>
1018 [% WHILE (post = posts.next) %]
1020 <title>[% post.title %]</title>
1021 <description>[% post.formatted_teaser|html%]</description>
1022 <pubDate>[% post.pub_date %]</pubDate>
1023 <guid>[% post.full_uri %]</guid>
1024 <link>[% post.full_uri %]</link>
1025 <dc:creator>[% post.author.screenname %]</dc:creator>
1031 =head3 Using XML::Feed
1033 A more robust solution is to use XML::Feed, as was done in the Catalyst
1034 Advent Calendar. Assuming we have a C<view> action that populates
1035 'entries' with some DBIx::Class iterator, the code would look something
1040 $c->forward('view'); # get the entries
1042 my $feed = XML::Feed->new('RSS');
1043 $feed->title( $c->config->{name} . ' RSS Feed' );
1044 $feed->link( $c->req->base ); # link to the site.
1045 $feed->description('Catalyst advent calendar'); Some description
1047 # Process the entries
1048 while( my $entry = $c->stash->{entries}->next ) {
1049 my $feed_entry = XML::Feed::Entry->new('RSS');
1050 $feed_entry->title($entry->title);
1051 $feed_entry->link( $c->uri_for($entry->link) );
1052 $feed_entry->issued( DateTime->from_epoch(epoch => $entry->created) );
1053 $feed->add_entry($feed_entry);
1055 $c->res->body( $feed->as_xml );
1058 A little more code in the controller, but with this approach you're
1059 pretty sure to get something that validates.
1061 Note that for both of the above aproaches, you'll need to set the
1062 content type like this:
1064 $c->res->content_type('application/rss+xml');
1068 You could generalize the second variant easily by replacing 'RSS' with a
1069 variable, so you can generate Atom feeds with the same code.
1071 Now, go ahead and make RSS feeds for all your stuff. The world *needs*
1072 updates on your goldfish!
1074 =head2 Forcing the browser to download content
1076 Sometimes you need your application to send content for download. For
1077 example, you can generate a comma-separated values (CSV) file for your
1078 users to download and import into their spreadsheet program.
1080 Let's say you have an C<Orders> controller which generates a CSV file
1081 in the C<export> action (i.e., C<http://localhost:3000/orders/export>):
1083 sub export : Local Args(0) {
1084 my ( $self, $c ) = @_;
1086 # In a real application, you'd generate this from the database
1087 my $csv = "1,5.99\n2,29.99\n3,3.99\n";
1089 $c->res->content_type('text/comma-separated-values');
1090 $c->res->body($csv);
1093 Normally the browser uses the last part of the URI to generate a
1094 filename for data it cannot display. In this case your browser would
1095 likely ask you to save a file named C<export>.
1097 Luckily you can have the browser download the content with a specific
1098 filename by setting the C<Content-Disposition> header:
1100 my $filename = 'Important Orders.csv';
1101 $c->res->header('Content-Disposition', qq[attachment; filename="$filename"]);
1103 Note the use of quotes around the filename; this ensures that any
1104 spaces in the filename are handled by the browser.
1106 Put this right before calling C<< $c->res->body >> and your browser
1107 will download a file named C<Important Orders.csv> instead of
1110 You can also use this to have the browser download content which it
1111 normally displays, such as JPEG images or even HTML. Just be sure to
1112 set the appropriate content type and disposition.
1117 Controllers are the main point of communication between the web server
1118 and your application. Here we explore some aspects of how they work.
1120 =head2 Extending RenderView (formerly DefaultEnd)
1122 The recommended approach for an C<end> action is to use
1123 L<Catalyst::Action::RenderView> (taking the place of
1124 L<Catalyst::Plugin::DefaultEnd>), which does what you usually need.
1125 However there are times when you need to add a bit to it, but don't want
1126 to write your own C<end> action.
1128 You can extend it like this:
1130 To add something to an C<end> action that is called before rendering
1131 (this is likely to be what you want), simply place it in the C<end>
1134 sub end : ActionClass('RenderView') {
1135 my ( $self, $c ) = @_;
1136 # do stuff here; the RenderView action is called afterwards
1139 To add things to an C<end> action that are called I<after> rendering,
1140 you can set it up like this:
1142 sub render : ActionClass('RenderView') { }
1145 my ( $self, $c ) = @_;
1146 $c->forward('render');
1154 A Catalyst application is driven by one or more Controller
1155 modules. There are a number of ways that Catalyst can decide which of
1156 the methods in your controller modules it should call. Controller
1157 methods are also called actions, because they determine how your
1158 catalyst application should (re-)act to any given URL. When the
1159 application is started up, catalyst looks at all your actions, and
1160 decides which URLs they map to.
1162 =head3 Type attributes
1164 Each action is a normal method in your controller, except that it has an
1165 L<attribute|http://search.cpan.org/~nwclark/perl-5.8.7/lib/attributes.pm>
1166 attached. These can be one of several types.
1168 Assume our Controller module starts with the following package declaration:
1170 package MyApp::Controller::Buckets;
1172 and we are running our application on localhost, port 3000 (the test
1179 A Path attribute also takes an argument, this can be either a relative
1180 or an absolute path. A relative path will be relative to the
1181 controller namespace, an absolute path will represent an exact
1184 sub my_handles : Path('handles') { .. }
1188 http://localhost:3000/buckets/handles
1192 sub my_handles : Path('/handles') { .. }
1196 http://localhost:3000/handles
1198 See also: L<Catalyst::DispatchType::Path>
1202 When using a Local attribute, no parameters are needed, instead, the
1203 name of the action is matched in the URL. The namespaces created by
1204 the name of the controller package is always part of the URL.
1206 sub my_handles : Local { .. }
1210 http://localhost:3000/buckets/my_handles
1214 A Global attribute is similar to a Local attribute, except that the
1215 namespace of the controller is ignored, and matching starts at root.
1217 sub my_handles : Global { .. }
1221 http://localhost:3000/my_handles
1225 By now you should have figured that a Regex attribute is just what it
1226 sounds like. This one takes a regular expression, and matches starting
1227 from root. These differ from the rest as they can match multiple URLs.
1229 sub my_handles : Regex('^handles') { .. }
1233 http://localhost:3000/handles
1237 http://localhost:3000/handles_and_other_parts
1241 See also: L<Catalyst::DispatchType::Regex>
1245 A LocalRegex is similar to a Regex, except it only matches below the current
1246 controller namespace.
1248 sub my_handles : LocalRegex(^handles') { .. }
1252 http://localhost:3000/buckets/handles
1256 http://localhost:3000/buckets/handles_and_other_parts
1262 See L<Catalyst::DispatchType::Chained> for a description of how the chained
1263 dispatch type works.
1267 Last but not least, there is the Private attribute, which allows you
1268 to create your own internal actions, which can be forwarded to, but
1269 won't be matched as URLs.
1271 sub my_handles : Private { .. }
1273 becomes nothing at all..
1275 Catalyst also predefines some special Private actions, which you can
1276 override, these are:
1282 The default action will be called, if no other matching action is
1283 found. If you don't have one of these in your namespace, or any sub
1284 part of your namespace, you'll get an error page instead. If you want
1285 to find out where it was the user was trying to go, you can look in
1286 the request object using C<< $c->req->path >>.
1288 sub default :Path { .. }
1290 works for all unknown URLs, in this controller namespace, or every one
1291 if put directly into MyApp.pm.
1295 The index action is called when someone tries to visit the exact
1296 namespace of your controller. If index, default and matching Path
1297 actions are defined, then index will be used instead of default and
1300 sub index :Path :Args(0) { .. }
1304 http://localhost:3000/buckets
1308 The begin action is called at the beginning of every request involving
1309 this namespace directly, before other matching actions are called. It
1310 can be used to set up variables/data for this particular part of your
1311 app. A single begin action is called, its always the one most relevant
1312 to the current namespace.
1314 sub begin : Private { .. }
1318 http://localhost:3000/bucket/(anything)?
1324 Like begin, this action is always called for the namespace it is in,
1325 after every other action has finished. It is commonly used to forward
1326 processing to the View component. A single end action is called, its
1327 always the one most relevant to the current namespace.
1330 sub end : Private { .. }
1332 is called once after any actions when
1334 http://localhost:3000/bucket/(anything)?
1340 Lastly, the auto action is magic in that B<every> auto action in the
1341 chain of paths up to and including the ending namespace, will be
1342 called. (In contrast, only one of the begin/end/default actions will
1343 be called, the relevant one).
1346 sub auto : Private { .. }
1350 sub auto : Private { .. }
1352 will both be called when visiting
1354 http://localhost:3000/bucket/(anything)?
1360 =head3 A word of warning
1362 Due to possible namespace conflicts with Plugins, it is advised to
1363 only put the pre-defined Private actions in your main MyApp.pm file,
1364 all others should go in a Controller module.
1366 =head3 More Information
1368 L<http://search.cpan.org/author/SRI/Catalyst-5.61/lib/Catalyst/Manual/Intro.pod>
1370 L<http://dev.catalyst.perl.org/wiki/FlowChart>
1372 =head2 DRY Controllers with Chained actions.
1374 Imagine that you would like the following paths in your application:
1378 =item B</cd/<ID>/track/<ID>>
1380 Displays info on a particular track.
1382 In the case of a multi-volume CD, this is the track sequence.
1384 =item B</cd/<ID>/volume/<ID>/track/<ID>>
1386 Displays info on a track on a specific volume.
1390 Here is some example code, showing how to do this with chained controllers:
1392 package CD::Controller;
1393 use base qw/Catalyst::Controller/;
1395 sub root : Chained('/') PathPart('/cd') CaptureArgs(1) {
1396 my ($self, $c, $cd_id) = @_;
1397 $c->stash->{cd_id} = $cd_id;
1398 $c->stash->{cd} = $self->model('CD')->find_by_id($cd_id);
1401 sub trackinfo : Chained('track') PathPart('') Args(0) RenderView {
1402 my ($self, $c) = @_;
1405 package CD::Controller::ByTrackSeq;
1406 use base qw/CD::Controller/;
1408 sub track : Chained('root') PathPart('track') CaptureArgs(1) {
1409 my ($self, $c, $track_seq) = @_;
1410 $c->stash->{track} = $self->stash->{cd}->find_track_by_seq($track_seq);
1413 package CD::Controller::ByTrackVolNo;
1414 use base qw/CD::Controller/;
1416 sub volume : Chained('root') PathPart('volume') CaptureArgs(1) {
1417 my ($self, $c, $volume) = @_;
1418 $c->stash->{volume} = $volume;
1421 sub track : Chained('volume') PathPart('track') CaptureArgs(1) {
1422 my ($self, $c, $track_no) = @_;
1423 $c->stash->{track} = $self->stash->{cd}->find_track_by_vol_and_track_no(
1424 $c->stash->{volume}, $track_no
1428 Note that adding other actions (i.e. chain endpoints) which operate on a track
1429 is simply a matter of adding a new sub to CD::Controller - no code is duplicated,
1430 even though there are two different methods of looking up a track.
1432 This technique can be expanded as needed to fulfil your requirements - for example,
1433 if you inherit the first action of a chain from a base class, then mixing in a
1434 different base class can be used to duplicate an entire URL hieratchy at a different
1435 point within your application.
1437 =head2 Component-based Subrequests
1439 See L<Catalyst::Plugin::SubRequest>.
1443 =head3 Single file upload with Catalyst
1445 To implement uploads in Catalyst, you need to have a HTML form similar to
1448 <form action="/upload" method="post" enctype="multipart/form-data">
1449 <input type="hidden" name="form_submit" value="yes">
1450 <input type="file" name="my_file">
1451 <input type="submit" value="Send">
1454 It's very important not to forget C<enctype="multipart/form-data"> in
1457 Catalyst Controller module 'upload' action:
1459 sub upload : Global {
1460 my ($self, $c) = @_;
1462 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1464 if ( my $upload = $c->request->upload('my_file') ) {
1466 my $filename = $upload->filename;
1467 my $target = "/tmp/upload/$filename";
1469 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1470 die( "Failed to copy '$filename' to '$target': $!" );
1475 $c->stash->{template} = 'file_upload.html';
1478 =head3 Multiple file upload with Catalyst
1480 Code for uploading multiple files from one form needs a few changes:
1482 The form should have this basic structure:
1484 <form action="/upload" method="post" enctype="multipart/form-data">
1485 <input type="hidden" name="form_submit" value="yes">
1486 <input type="file" name="file1" size="50"><br>
1487 <input type="file" name="file2" size="50"><br>
1488 <input type="file" name="file3" size="50"><br>
1489 <input type="submit" value="Send">
1492 And in the controller:
1494 sub upload : Local {
1495 my ($self, $c) = @_;
1497 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
1499 for my $field ( $c->req->upload ) {
1501 my $upload = $c->req->upload($field);
1502 my $filename = $upload->filename;
1503 my $target = "/tmp/upload/$filename";
1505 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
1506 die( "Failed to copy '$filename' to '$target': $!" );
1511 $c->stash->{template} = 'file_upload.html';
1514 C<for my $field ($c-E<gt>req->upload)> loops automatically over all file
1515 input fields and gets input names. After that is basic file saving code,
1516 just like in single file upload.
1518 Notice: C<die>ing might not be what you want to do, when an error
1519 occurs, but it works as an example. A better idea would be to store
1520 error C<$!> in $c->stash->{error} and show a custom error template
1521 displaying this message.
1523 For more information about uploads and usable methods look at
1524 L<Catalyst::Request::Upload> and L<Catalyst::Request>.
1526 =head2 Forwarding with arguments
1528 Sometimes you want to pass along arguments when forwarding to another
1529 action. As of version 5.30, arguments can be passed in the call to
1530 C<forward>; in earlier versions, you can manually set the arguments in
1531 the Catalyst Request object:
1533 # version 5.30 and later:
1534 $c->forward('/wherever', [qw/arg1 arg2 arg3/]);
1537 $c->req->args([qw/arg1 arg2 arg3/]);
1538 $c->forward('/wherever');
1540 (See the L<Catalyst::Manual::Intro> Flow_Control section for more
1541 information on passing arguments via C<forward>.)
1543 =head2 Chained dispatch using base classes, and inner packages.
1545 package MyApp::Controller::Base;
1546 use base qw/Catalyst::Controller/;
1548 sub key1 : Chained('/')
1552 The recipes below describe aspects of the deployment process,
1553 including web server engines and tips to improve application efficiency.
1555 =head2 mod_perl Deployment
1557 mod_perl is the best solution for many applications, but we'll list some pros
1558 and cons so you can decide for yourself. The other production deployment
1559 option is FastCGI, for which see below.
1565 mod_perl is very fast and your app will benefit from being loaded in memory
1566 within each Apache process.
1568 =head4 Shared memory for multiple apps
1570 If you need to run several Catalyst apps on the same server, mod_perl will
1571 share the memory for common modules.
1577 Since your application is fully loaded in memory, every Apache process will
1578 be rather large. This means a large Apache process will be tied up while
1579 serving static files, large files, or dealing with slow clients. For this
1580 reason, it is best to run a two-tiered web architecture with a lightweight
1581 frontend server passing dynamic requests to a large backend mod_perl
1586 Any changes made to the core code of your app require a full Apache restart.
1587 Catalyst does not support Apache::Reload or StatINC. This is another good
1588 reason to run a frontend web server where you can set up an
1589 C<ErrorDocument 502> page to report that your app is down for maintenance.
1591 =head4 Cannot run multiple versions of the same app
1593 It is not possible to run two different versions of the same application in
1594 the same Apache instance because the namespaces will collide.
1598 Now that we have that out of the way, let's talk about setting up mod_perl
1599 to run a Catalyst app.
1601 =head4 1. Install Catalyst::Engine::Apache
1603 You should install the latest versions of both Catalyst and
1604 Catalyst::Engine::Apache. The Apache engines were separated from the
1605 Catalyst core in version 5.50 to allow for updates to the engine without
1606 requiring a new Catalyst release.
1608 =head4 2. Install Apache with mod_perl
1610 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
1611 recommended. With Apache 2, make sure you are using the prefork MPM and not
1612 the worker MPM. The reason for this is that many Perl modules are not
1613 thread-safe and may have problems running within the threaded worker
1614 environment. Catalyst is thread-safe however, so if you know what you're
1615 doing, you may be able to run using worker.
1617 In Debian, the following commands should get you going.
1619 apt-get install apache2-mpm-prefork
1620 apt-get install libapache2-mod-perl2
1622 =head4 3. Configure your application
1624 Every Catalyst application will automagically become a mod_perl handler
1625 when run within mod_perl. This makes the configuration extremely easy.
1626 Here is a basic Apache 2 configuration.
1628 PerlSwitches -I/var/www/MyApp/lib
1633 PerlResponseHandler MyApp
1636 The most important line here is C<PerlModule MyApp>. This causes mod_perl
1637 to preload your entire application into shared memory, including all of your
1638 controller, model, and view classes and configuration. If you have -Debug
1639 mode enabled, you will see the startup output scroll by when you first
1642 For an example Apache 1.3 configuration, please see the documentation for
1643 L<Catalyst::Engine::Apache::MP13>.
1647 That's it, your app is now a full-fledged mod_perl application! Try it out
1648 by going to http://your.server.com/.
1650 =head3 Other Options
1652 =head4 Non-root location
1654 You may not always want to run your app at the root of your server or virtual
1655 host. In this case, it's a simple change to run at any non-root location
1660 PerlResponseHandler MyApp
1663 When running this way, it is best to make use of the C<uri_for> method in
1664 Catalyst for constructing correct links.
1666 =head4 Static file handling
1668 Static files can be served directly by Apache for a performance boost.
1670 DocumentRoot /var/www/MyApp/root
1672 SetHandler default-handler
1675 This will let all files within root/static be handled directly by Apache. In
1676 a two-tiered setup, the frontend server should handle static files.
1677 The configuration to do this on the frontend will vary.
1679 The same is accomplished in lighttpd with the following snippet:
1681 $HTTP["url"] !~ "^/(?:img/|static/|css/|favicon.ico$)" {
1685 "socket" => "/tmp/myapp.socket",
1686 "check-local" => "disable",
1692 Which serves everything in the img, static, css directories
1693 statically, as well as the favicon file.
1695 Note the path of the application needs to be stated explicitly in the
1696 web server configuration for both these recipes.
1698 =head2 Catalyst on shared hosting
1700 So, you want to put your Catalyst app out there for the whole world to
1701 see, but you don't want to break the bank. There is an answer - if you
1702 can get shared hosting with FastCGI and a shell, you can install your
1703 Catalyst app in a local directory on your shared host. First, run
1705 perl -MCPAN -e shell
1707 and go through the standard CPAN configuration process. Then exit out
1708 without installing anything. Next, open your .bashrc and add
1710 export PATH=$HOME/local/bin:$HOME/local/script:$PATH
1711 perlversion=`perl -v | grep 'built for' | awk '{print $4}' | sed -e 's/v//;'`
1712 export PERL5LIB=$HOME/local/share/perl/$perlversion:$HOME/local/lib/perl/$perlversion:$HOME/local/lib:$PERL5LIB
1714 and log out, then back in again (or run C<". .bashrc"> if you
1715 prefer). Finally, edit C<.cpan/CPAN/MyConfig.pm> and add
1717 'make_install_arg' => qq[SITEPREFIX=$ENV{HOME}/local],
1718 'makepl_arg' => qq[INSTALLDIRS=site install_base=$ENV{HOME}/local],
1720 Now you can install the modules you need using CPAN as normal; they
1721 will be installed into your local directory, and perl will pick them
1722 up. Finally, change directory into the root of your virtual host and
1723 symlink your application's script directory in:
1725 cd path/to/mydomain.com
1726 ln -s ~/lib/MyApp/script script
1728 And add the following lines to your .htaccess file (assuming the server
1729 is setup to handle .pl as fcgi - you may need to rename the script to
1730 myapp_fastcgi.fcgi and/or use a SetHandler directive):
1733 RewriteCond %{REQUEST_URI} !^/?script/myapp_fastcgi.pl
1734 RewriteRule ^(.*)$ script/myapp_fastcgi.pl/$1 [PT,L]
1736 Now C<http://mydomain.com/> should now Just Work. Congratulations, now
1737 you can tell your friends about your new website (or in our case, tell
1738 the client it's time to pay the invoice :) )
1740 =head2 FastCGI Deployment
1742 FastCGI is a high-performance extension to CGI. It is suitable
1743 for production environments.
1749 FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you;
1750 your app runs as multiple persistent processes ready to receive connections
1751 from the web server.
1755 When using external FastCGI servers, your application runs as a standalone
1756 application server. It may be restarted independently from the web server.
1757 This allows for a more robust environment and faster reload times when
1758 pushing new app changes. The frontend server can even be configured to
1759 display a friendly "down for maintenance" page while the application is
1762 =head4 Load-balancing
1764 You can launch your application on multiple backend servers and allow the
1765 frontend web server to load-balance between all of them. And of course, if
1766 one goes down, your app continues to run fine.
1768 =head4 Multiple versions of the same app
1770 Each FastCGI application is a separate process, so you can run different
1771 versions of the same app on a single server.
1773 =head4 Can run with threaded Apache
1775 Since your app is not running inside of Apache, the faster mpm_worker module
1776 can be used without worrying about the thread safety of your application.
1780 =head4 More complex environment
1782 With FastCGI, there are more things to monitor and more processes running
1783 than when using mod_perl.
1787 =head4 1. Install Apache with mod_fastcgi
1789 mod_fastcgi for Apache is a third party module, and can be found at
1790 L<http://www.fastcgi.com/>. It is also packaged in many distributions,
1791 for example, libapache2-mod-fastcgi in Debian.
1793 =head4 2. Configure your application
1795 # Serve static content directly
1796 DocumentRoot /var/www/MyApp/root
1797 Alias /static /var/www/MyApp/root/static
1799 FastCgiServer /var/www/MyApp/script/myapp_fastcgi.pl -processes 3
1800 Alias /myapp/ /var/www/MyApp/script/myapp_fastcgi.pl/
1802 # Or, run at the root
1803 Alias / /var/www/MyApp/script/myapp_fastcgi.pl/
1805 The above commands will launch 3 app processes and make the app available at
1808 =head3 Standalone server mode
1810 While not as easy as the previous method, running your app as an external
1811 server gives you much more flexibility.
1813 First, launch your app as a standalone server listening on a socket.
1815 script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5 -p /tmp/myapp.pid -d
1817 You can also listen on a TCP port if your web server is not on the same
1820 script/myapp_fastcgi.pl -l :8080 -n 5 -p /tmp/myapp.pid -d
1822 You will probably want to write an init script to handle starting/stopping
1823 of the app using the pid file.
1825 Now, we simply configure Apache to connect to the running server.
1827 # 502 is a Bad Gateway error, and will occur if the backend server is down
1828 # This allows us to display a friendly static page that says "down for
1830 Alias /_errors /var/www/MyApp/root/error-pages
1831 ErrorDocument 502 /_errors/502.html
1833 FastCgiExternalServer /tmp/myapp.fcgi -socket /tmp/myapp.socket
1834 Alias /myapp/ /tmp/myapp.fcgi/
1836 # Or, run at the root
1837 Alias / /tmp/myapp.fcgi/
1841 L<Catalyst::Engine::FastCGI>.
1843 =head2 Development server deployment
1845 The development server is a mini web server written in perl. If you
1846 expect a low number of hits or you don't need mod_perl/FastCGI speed,
1847 you could use the development server as the application server with a
1848 lightweight proxy web server at the front. However, consider using
1849 L<Catalyst::Engine::HTTP::Prefork> for this kind of deployment instead, since
1850 it can better handle multiple concurrent requests without forking, or can
1851 prefork a set number of servers for improved performance.
1855 As this is an application server setup, the pros are the same as
1856 FastCGI (with the exception of speed).
1861 The development server is what you create your code on, so if it works
1862 here, it should work in production!
1868 Not as fast as mod_perl or FastCGI. Needs to fork for each request
1869 that comes in - make sure static files are served by the web server to
1874 =head4 Start up the development server
1876 script/myapp_server.pl -p 8080 -k -f -pidfile=/tmp/myapp.pid
1878 You will probably want to write an init script to handle stop/starting
1879 the app using the pid file.
1881 =head4 Configuring Apache
1883 Make sure mod_proxy is enabled and add:
1885 # Serve static content directly
1886 DocumentRoot /var/www/MyApp/root
1887 Alias /static /var/www/MyApp/root/static
1895 # Need to specifically stop these paths from being passed to proxy
1897 ProxyPass /favicon.ico !
1899 ProxyPass / http://localhost:8080/
1900 ProxyPassReverse / http://localhost:8080/
1902 # This is optional if you'd like to show a custom error page
1903 # if the proxy is not available
1904 ErrorDocument 502 /static/error_pages/http502.html
1906 You can wrap the above within a VirtualHost container if you want
1907 different apps served on the same host.
1909 =head2 Quick deployment: Building PAR Packages
1911 You have an application running on your development box, but then you
1912 have to quickly move it to another one for
1913 demonstration/deployment/testing...
1915 PAR packages can save you from a lot of trouble here. They are usual Zip
1916 files that contain a blib tree; you can even include all prereqs and a
1917 perl interpreter by setting a few flags!
1919 =head3 Follow these few points to try it out!
1921 1. Install Catalyst and PAR 0.89 (or later)
1923 % perl -MCPAN -e 'install Catalyst'
1925 % perl -MCPAN -e 'install PAR'
1928 2. Create a application
1934 Recent versions of Catalyst (5.62 and up) include
1935 L<Module::Install::Catalyst>, which simplifies the process greatly. From the shell in your application directory:
1940 Congratulations! Your package "myapp.par" is ready, the following
1941 steps are just optional.
1943 3. Test your PAR package with "parl" (no typo)
1947 [parl] myapp[.par] [script] [arguments]
1950 parl myapp.par myapp_server.pl -r
1960 % parl myapp.par myapp_server.pl
1961 You can connect to your server at http://localhost:3000
1963 Yes, this nifty little starter application gets automatically included.
1964 You can also use "catalyst_par_script('myapp_server.pl')" to set a
1965 default script to execute.
1967 6. Want to create a binary that includes the Perl interpreter?
1969 % pp -o myapp myapp.par
1970 % ./myapp myapp_server.pl
1971 You can connect to your server at http://localhost:3000
1973 =head2 Serving static content
1975 Serving static content in Catalyst used to be somewhat tricky; the use
1976 of L<Catalyst::Plugin::Static::Simple> makes everything much easier.
1977 This plugin will automatically serve your static content during development,
1978 but allows you to easily switch to Apache (or other server) in a
1979 production environment.
1981 =head3 Introduction to Static::Simple
1983 Static::Simple is a plugin that will help to serve static content for your
1984 application. By default, it will serve most types of files, excluding some
1985 standard Template Toolkit extensions, out of your B<root> file directory. All
1986 files are served by path, so if B<images/me.jpg> is requested, then
1987 B<root/images/me.jpg> is found and served.
1991 Using the plugin is as simple as setting your use line in MyApp.pm to include:
1993 use Catalyst qw/Static::Simple/;
1995 and already files will be served.
1999 Static content is best served from a single directory within your root
2000 directory. Having many different directories such as C<root/css> and
2001 C<root/images> requires more code to manage, because you must separately
2002 identify each static directory--if you decide to add a C<root/js>
2003 directory, you'll need to change your code to account for it. In
2004 contrast, keeping all static directories as subdirectories of a main
2005 C<root/static> directory makes things much easier to manage. Here's an
2006 example of a typical root directory structure:
2010 root/controller/stuff.tt
2013 root/static/css/main.css
2014 root/static/images/logo.jpg
2015 root/static/js/code.js
2018 All static content lives under C<root/static>, with everything else being
2019 Template Toolkit files.
2025 You may of course want to change the default locations, and make
2026 Static::Simple look somewhere else, this is as easy as:
2028 MyApp->config->{static}->{include_path} = [
2029 MyApp->config->{root},
2033 When you override include_path, it will not automatically append the
2034 normal root path, so you need to add it yourself if you still want
2035 it. These will be searched in order given, and the first matching file
2038 =item Static directories
2040 If you want to force some directories to be only static, you can set
2041 them using paths relative to the root dir, or regular expressions:
2043 MyApp->config->{static}->{dirs} = [
2048 =item File extensions
2050 By default, the following extensions are not served (that is, they will
2051 be processed by Catalyst): B<tmpl, tt, tt2, html, xhtml>. This list can
2054 MyApp->config->{static}->{ignore_extensions} = [
2055 qw/tmpl tt tt2 html xhtml/
2058 =item Ignoring directories
2060 Entire directories can be ignored. If used with include_path,
2061 directories relative to the include_path dirs will also be ignored:
2063 MyApp->config->{static}->{ignore_dirs} = [ qw/tmpl css/ ];
2067 =head3 More information
2069 L<http://search.cpan.org/dist/Catalyst-Plugin-Static-Simple/>
2071 =head3 Serving manually with the Static plugin with HTTP::Daemon (myapp_server.pl)
2073 In some situations you might want to control things more directly,
2074 using L<Catalyst::Plugin::Static>.
2076 In your main application class (MyApp.pm), load the plugin:
2078 use Catalyst qw/-Debug FormValidator Static OtherPlugin/;
2080 You will also need to make sure your end method does I<not> forward
2081 static content to the view, perhaps like this:
2084 my ( $self, $c ) = @_;
2086 $c->forward( 'MyApp::View::TT' )
2087 unless ( $c->res->body || !$c->stash->{template} );
2090 This code will only forward to the view if a template has been
2091 previously defined by a controller and if there is not already data in
2092 C<$c-E<gt>res-E<gt>body>.
2094 Next, create a controller to handle requests for the /static path. Use
2095 the Helper to save time. This command will create a stub controller as
2096 C<lib/MyApp/Controller/Static.pm>.
2098 $ script/myapp_create.pl controller Static
2100 Edit the file and add the following methods:
2102 # serve all files under /static as static files
2103 sub default : Path('/static') {
2104 my ( $self, $c ) = @_;
2106 # Optional, allow the browser to cache the content
2107 $c->res->headers->header( 'Cache-Control' => 'max-age=86400' );
2109 $c->serve_static; # from Catalyst::Plugin::Static
2112 # also handle requests for /favicon.ico
2113 sub favicon : Path('/favicon.ico') {
2114 my ( $self, $c ) = @_;
2119 You can also define a different icon for the browser to use instead of
2120 favicon.ico by using this in your HTML header:
2122 <link rel="icon" href="/static/myapp.ico" type="image/x-icon" />
2124 =head3 Common problems with the Static plugin
2126 The Static plugin makes use of the C<shared-mime-info> package to
2127 automatically determine MIME types. This package is notoriously
2128 difficult to install, especially on win32 and OS X. For OS X the easiest
2129 path might be to install Fink, then use C<apt-get install
2130 shared-mime-info>. Restart the server, and everything should be fine.
2132 Make sure you are using the latest version (>= 0.16) for best
2133 results. If you are having errors serving CSS files, or if they get
2134 served as text/plain instead of text/css, you may have an outdated
2135 shared-mime-info version. You may also wish to simply use the following
2136 code in your Static controller:
2138 if ($c->req->path =~ /css$/i) {
2139 $c->serve_static( "text/css" );
2144 =head3 Serving Static Files with Apache
2146 When using Apache, you can bypass Catalyst and any Static
2147 plugins/controllers controller by intercepting requests for the
2148 C<root/static> path at the server level. All that is required is to
2149 define a DocumentRoot and add a separate Location block for your static
2150 content. Here is a complete config for this application under mod_perl
2154 use lib qw(/var/www/MyApp/lib);
2159 ServerName myapp.example.com
2160 DocumentRoot /var/www/MyApp/root
2162 SetHandler perl-script
2165 <LocationMatch "/(static|favicon.ico)">
2166 SetHandler default-handler
2170 And here's a simpler example that'll get you started:
2172 Alias /static/ "/my/static/files/"
2173 <Location "/static">
2179 Catalyst makes it easy to employ several different types of caching to
2180 speed up your applications.
2182 =head3 Cache Plugins
2184 There are three wrapper plugins around common CPAN cache modules:
2185 Cache::FastMmap, Cache::FileCache, and Cache::Memcached. These can be
2186 used to cache the result of slow operations.
2188 The Catalyst Advent Calendar uses the FileCache plugin to cache the
2189 rendered XHTML version of the source POD document. This is an ideal
2190 application for a cache because the source document changes
2191 infrequently but may be viewed many times.
2193 use Catalyst qw/Cache::FileCache/;
2198 sub render_pod : Local {
2199 my ( self, $c ) = @_;
2201 # the cache is keyed on the filename and the modification time
2202 # to check for updates to the file.
2203 my $file = $c->path_to( 'root', '2005', '11.pod' );
2204 my $mtime = ( stat $file )->mtime;
2206 my $cached_pod = $c->cache->get("$file $mtime");
2207 if ( !$cached_pod ) {
2208 $cached_pod = do_slow_pod_rendering();
2209 # cache the result for 12 hours
2210 $c->cache->set( "$file $mtime", $cached_pod, '12h' );
2212 $c->stash->{pod} = $cached_pod;
2215 We could actually cache the result forever, but using a value such as 12 hours
2216 allows old entries to be automatically expired when they are no longer needed.
2220 Another method of caching is to cache the entire HTML page. While this is
2221 traditionally handled by a front-end proxy server like Squid, the Catalyst
2222 PageCache plugin makes it trivial to cache the entire output from
2223 frequently-used or slow actions.
2225 Many sites have a busy content-filled front page that might look something
2226 like this. It probably takes a while to process, and will do the exact same
2227 thing for every single user who views the page.
2229 sub front_page : Path('/') {
2230 my ( $self, $c ) = @_;
2232 $c->forward( 'get_news_articles' );
2233 $c->forward( 'build_lots_of_boxes' );
2234 $c->forward( 'more_slow_stuff' );
2236 $c->stash->{template} = 'index.tt';
2239 We can add the PageCache plugin to speed things up.
2241 use Catalyst qw/Cache::FileCache PageCache/;
2243 sub front_page : Path ('/') {
2244 my ( $self, $c ) = @_;
2246 $c->cache_page( 300 );
2248 # same processing as above
2251 Now the entire output of the front page, from <html> to </html>, will be
2252 cached for 5 minutes. After 5 minutes, the next request will rebuild the
2253 page and it will be re-cached.
2255 Note that the page cache is keyed on the page URI plus all parameters, so
2256 requests for / and /?foo=bar will result in different cache items. Also,
2257 only GET requests will be cached by the plugin.
2259 You can even get that front-end Squid proxy to help out by enabling HTTP
2260 headers for the cached page.
2262 MyApp->config->{page_cache}->{set_http_headers} = 1;
2264 This would now set the following headers so proxies and browsers may cache
2265 the content themselves.
2267 Cache-Control: max-age=($expire_time - time)
2268 Expires: $expire_time
2269 Last-Modified: $cache_created_time
2271 =head3 Template Caching
2273 Template Toolkit provides support for caching compiled versions of your
2274 templates. To enable this in Catalyst, use the following configuration.
2275 TT will cache compiled templates keyed on the file mtime, so changes will
2276 still be automatically detected.
2278 package MyApp::View::TT;
2282 use base 'Catalyst::View::TT';
2284 __PACKAGE__->config(
2285 COMPILE_DIR => '/tmp/template_cache',
2292 See the documentation for each cache plugin for more details and other
2293 available configuration options.
2295 L<Catalyst::Plugin::Cache::FastMmap>
2296 L<Catalyst::Plugin::Cache::FileCache>
2297 L<Catalyst::Plugin::Cache::Memcached>
2298 L<Catalyst::Plugin::PageCache>
2299 L<http://search.cpan.org/dist/Template-Toolkit/lib/Template/Manual/Config.pod#Caching_and_Compiling_Options>
2303 Testing is an integral part of the web application development
2304 process. Tests make multi developer teams easier to coordinate, and
2305 they help ensure that there are no nasty surprises after upgrades or
2310 Catalyst provides a convenient way of testing your application during
2311 development and before deployment in a real environment.
2313 C<Catalyst::Test> makes it possible to run the same tests both locally
2314 (without an external daemon) and against a remote server via HTTP.
2318 Let's examine a skeleton application's C<t/> directory:
2320 mundus:~/MyApp chansen$ ls -l t/
2322 -rw-r--r-- 1 chansen chansen 95 18 Dec 20:50 01app.t
2323 -rw-r--r-- 1 chansen chansen 190 18 Dec 20:50 02pod.t
2324 -rw-r--r-- 1 chansen chansen 213 18 Dec 20:50 03podcoverage.t
2330 Verifies that the application loads, compiles, and returns a successful
2335 Verifies that all POD is free from errors. Only executed if the C<TEST_POD>
2336 environment variable is true.
2338 =item C<03podcoverage.t>
2340 Verifies that all methods/functions have POD coverage. Only executed if the
2341 C<TEST_POD> environment variable is true.
2345 =head3 Creating tests
2347 mundus:~/MyApp chansen$ cat t/01app.t | perl -ne 'printf( "%2d %s", $., $_ )'
2348 1 use Test::More tests => 2;
2349 2 use_ok( Catalyst::Test, 'MyApp' );
2351 4 ok( request('/')->is_success );
2353 The first line declares how many tests we are going to run, in this case
2354 two. The second line tests and loads our application in test mode. The
2355 fourth line verifies that our application returns a successful response.
2357 C<Catalyst::Test> exports two functions, C<request> and C<get>. Each can
2358 take three different arguments:
2362 =item A string which is a relative or absolute URI.
2364 request('/my/path');
2365 request('http://www.host.com/my/path');
2367 =item An instance of C<URI>.
2369 request( URI->new('http://www.host.com/my/path') );
2371 =item An instance of C<HTTP::Request>.
2373 request( HTTP::Request->new( GET => 'http://www.host.com/my/path') );
2377 C<request> returns an instance of C<HTTP::Response> and C<get> returns the
2378 content (body) of the response.
2380 =head3 Running tests locally
2382 mundus:~/MyApp chansen$ CATALYST_DEBUG=0 TEST_POD=1 prove --lib lib/ t/
2383 t/01app............ok
2384 t/02pod............ok
2385 t/03podcoverage....ok
2386 All tests successful.
2387 Files=3, Tests=4, 2 wallclock secs ( 1.60 cusr + 0.36 csys = 1.96 CPU)
2389 C<CATALYST_DEBUG=0> ensures that debugging is off; if it's enabled you
2390 will see debug logs between tests.
2392 C<TEST_POD=1> enables POD checking and coverage.
2394 C<prove> A command-line tool that makes it easy to run tests. You can
2395 find out more about it from the links below.
2397 =head3 Running tests remotely
2399 mundus:~/MyApp chansen$ CATALYST_SERVER=http://localhost:3000/ prove --lib lib/ t/01app.t
2401 All tests successful.
2402 Files=1, Tests=2, 0 wallclock secs ( 0.40 cusr + 0.01 csys = 0.41 CPU)
2404 C<CATALYST_SERVER=http://localhost:3000/> is the absolute deployment URI of
2405 your application. In C<CGI> or C<FastCGI> it should be the host and path
2408 =head3 C<Test::WWW::Mechanize> and Catalyst
2410 Be sure to check out C<Test::WWW::Mechanize::Catalyst>. It makes it easy to
2411 test HTML, forms and links. A short example of usage:
2413 use Test::More tests => 6;
2414 use_ok( Test::WWW::Mechanize::Catalyst, 'MyApp' );
2416 my $mech = Test::WWW::Mechanize::Catalyst->new;
2417 $mech->get_ok("http://localhost/", 'Got index page');
2418 $mech->title_like( qr/^MyApp on Catalyst/, 'Got right index title' );
2419 ok( $mech->find_link( text_regex => qr/^Wiki/i ), 'Found link to Wiki' );
2420 ok( $mech->find_link( text_regex => qr/^Mailing-List/i ), 'Found link to Mailing-List' );
2421 ok( $mech->find_link( text_regex => qr/^IRC channel/i ), 'Found link to IRC channel' );
2423 =head3 Further Reading
2427 =item Catalyst::Test
2429 L<http://search.cpan.org/dist/Catalyst/lib/Catalyst/Test.pm>
2431 =item Test::WWW::Mechanize::Catalyst
2433 L<http://search.cpan.org/dist/Test-WWW-Mechanize-Catalyst/lib/Test/WWW/Mechanize/Catalyst.pm>
2435 =item Test::WWW::Mechanize
2437 L<http://search.cpan.org/dist/Test-WWW-Mechanize/Mechanize.pm>
2439 =item WWW::Mechanize
2441 L<http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm>
2443 =item LWP::UserAgent
2445 L<http://search.cpan.org/dist/libwww-perl/lib/LWP/UserAgent.pm>
2449 L<http://search.cpan.org/dist/libwww-perl/lib/HTML/Form.pm>
2453 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Message.pm>
2457 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request.pm>
2459 =item HTTP::Request::Common
2461 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request/Common.pm>
2463 =item HTTP::Response
2465 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Response.pm>
2469 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Status.pm>
2473 L<http://search.cpan.org/dist/URI/URI.pm>
2477 L<http://search.cpan.org/dist/Test-Simple/lib/Test/More.pm>
2481 L<http://search.cpan.org/dist/Test-Pod/Pod.pm>
2483 =item Test::Pod::Coverage
2485 L<http://search.cpan.org/dist/Test-Pod-Coverage/Coverage.pm>
2487 =item prove (Test::Harness)
2489 L<http://search.cpan.org/dist/Test-Harness/bin/prove>
2493 =head3 More Information
2495 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::Roles>
2496 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::ACL>
2500 Sebastian Riedel C<sri@oook.de>
2502 Danijel Milicevic C<me@danijel.de>
2504 Viljo Marrandi C<vilts@yahoo.com>
2506 Marcus Ramberg C<mramberg@cpan.org>
2508 Jesse Sheidlower C<jester@panix.com>
2510 Andy Grundman C<andy@hybridized.org>
2512 Chisel Wright C<pause@herlpacker.co.uk>
2514 Will Hawes C<info@whawes.co.uk>
2516 Gavin Henry C<ghenry@perl.me.uk>
2518 Kieren Diment C<kd@totaldatasolution.com>
2522 This document is free, you can redistribute it and/or modify it
2523 under the same terms as Perl itself.