4 Catalyst::Manual::Cookbook - Cooking with Catalyst
8 Yummy code like your mum used to bake!
12 =head2 Force debug screen
14 You can force Catalyst to display the debug screen at the end of the
15 request by placing a C<die()> call in the C<end> action.
18 my ( $self, $c ) = @_;
22 If you're tired of removing and adding this all the time, you can add a
23 condition in the C<end> action. For example:
26 my ( $self, $c ) = @_;
27 die "forced debug" if $c->req->params->{dump_info};
30 Then just add to your query string C<&dump_info=1> (or if there's no
31 query string for the request, add C<?dump_info=1> to the end of the URL)
32 to force debug output. This feature is included in
33 L<Catalyst::Action::RenderView> (formerly
34 L<Catalyst::Plugin::DefaultEnd>).
37 =head2 Disable statistics
39 Just add this line to your application class if you don't want those nifty
40 statistics in your debug messages.
42 sub Catalyst::Log::info { }
44 =head2 Enable debug status in the environment
46 Normally you enable the debugging info by adding the C<-Debug> flag to
47 your C<use Catalyst> statement. However, you can also enable it using
48 environment variable, so you can (for example) get debug info without
49 modifying your application scripts. Just set C<CATALYST_DEBUG> or
50 C<E<lt>MYAPPE<gt>_DEBUG> to a true value.
54 =head3 Single file upload with Catalyst
56 To implement uploads in Catalyst, you need to have a HTML form similar to
59 <form action="/upload" method="post" enctype="multipart/form-data">
60 <input type="hidden" name="form_submit" value="yes">
61 <input type="file" name="my_file">
62 <input type="submit" value="Send">
65 It's very important not to forget C<enctype="multipart/form-data"> in
68 Catalyst Controller module 'upload' action:
73 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
75 if ( my $upload = $c->request->upload('my_file') ) {
77 my $filename = $upload->filename;
78 my $target = "/tmp/upload/$filename";
80 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
81 die( "Failed to copy '$filename' to '$target': $!" );
86 $c->stash->{template} = 'file_upload.html';
89 =head3 Multiple file upload with Catalyst
91 Code for uploading multiple files from one form needs a few changes:
93 The form should have this basic structure:
95 <form action="/upload" method="post" enctype="multipart/form-data">
96 <input type="hidden" name="form_submit" value="yes">
97 <input type="file" name="file1" size="50"><br>
98 <input type="file" name="file2" size="50"><br>
99 <input type="file" name="file3" size="50"><br>
100 <input type="submit" value="Send">
103 And in the controller:
108 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
110 for my $field ( $c->req->upload ) {
112 my $upload = $c->req->upload($field);
113 my $filename = $upload->filename;
114 my $target = "/tmp/upload/$filename";
116 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
117 die( "Failed to copy '$filename' to '$target': $!" );
122 $c->stash->{template} = 'file_upload.html';
125 C<for my $field ($c-E<gt>req->upload)> loops automatically over all file
126 input fields and gets input names. After that is basic file saving code,
127 just like in single file upload.
129 Notice: C<die>ing might not be what you want to do, when an error
130 occurs, but it works as an example. A better idea would be to store
131 error C<$!> in $c->stash->{error} and show a custom error template
132 displaying this message.
134 For more information about uploads and usable methods look at
135 L<Catalyst::Request::Upload> and L<Catalyst::Request>.
137 =head2 Authentication (logging in)
139 This is extensively covered in other documentation; see in particular
140 L<Catalyst::Plugin::Authentication> and the Authentication chapter
141 of the Tutorial at L<Catalyst::Manual::Tutorial::Authorization>.
143 =head2 Pass-through login (and other actions)
145 An easy way of having assorted actions that occur during the processing
146 of a request that are orthogonal to its actual purpose - logins, silent
147 commands etc. Provide actions for these, but when they're required for
148 something else fill e.g. a form variable __login and have a sub begin
151 sub begin : Private {
153 foreach my $action (qw/login docommand foo bar whatever/) {
154 if ($c->req->params->{"__${action}"}) {
155 $c->forward($action);
161 =head2 Serving static content
163 Serving static content in Catalyst used to be somewhat tricky; the use
164 of L<Catalyst::Plugin::Static::Simple> makes everything much easier.
165 This plugin will automatically serve your static content during development,
166 but allows you to easily switch to Apache (or other server) in a
167 production environment.
169 =head3 Introduction to Static::Simple
171 Static::Simple is a plugin that will help to serve static content for your
172 application. By default, it will serve most types of files, excluding some
173 standard Template Toolkit extensions, out of your B<root> file directory. All
174 files are served by path, so if B<images/me.jpg> is requested, then
175 B<root/images/me.jpg> is found and served.
179 Using the plugin is as simple as setting your use line in MyApp.pm to include:
181 use Catalyst qw/Static::Simple/;
183 and already files will be served.
187 Static content is best served from a single directory within your root
188 directory. Having many different directories such as C<root/css> and
189 C<root/images> requires more code to manage, because you must separately
190 identify each static directory--if you decide to add a C<root/js>
191 directory, you'll need to change your code to account for it. In
192 contrast, keeping all static directories as subdirectories of a main
193 C<root/static> directory makes things much easier to manage. Here's an
194 example of a typical root directory structure:
198 root/controller/stuff.tt
201 root/static/css/main.css
202 root/static/images/logo.jpg
203 root/static/js/code.js
206 All static content lives under C<root/static>, with everything else being
207 Template Toolkit files.
213 You may of course want to change the default locations, and make
214 Static::Simple look somewhere else, this is as easy as:
216 MyApp->config->{static}->{include_path} = [
217 MyApp->config->{root},
221 When you override include_path, it will not automatically append the
222 normal root path, so you need to add it yourself if you still want
223 it. These will be searched in order given, and the first matching file
226 =item Static directories
228 If you want to force some directories to be only static, you can set
229 them using paths relative to the root dir, or regular expressions:
231 MyApp->config->{static}->{dirs} = [
236 =item File extensions
238 By default, the following extensions are not served (that is, they will
239 be processed by Catalyst): B<tmpl, tt, tt2, html, xhtml>. This list can
242 MyApp->config->{static}->{ignore_extensions} = [
243 qw/tmpl tt tt2 html xhtml/
246 =item Ignoring directories
248 Entire directories can be ignored. If used with include_path,
249 directories relative to the include_path dirs will also be ignored:
251 MyApp->config->{static}->{ignore_dirs} = [ qw/tmpl css/ ];
255 =head3 More information
257 L<http://search.cpan.org/dist/Catalyst-Plugin-Static-Simple/>
259 =head3 Serving manually with the Static plugin with HTTP::Daemon (myapp_server.pl)
261 In some situations you might want to control things more directly,
262 using L<Catalyst::Plugin::Static>.
264 In your main application class (MyApp.pm), load the plugin:
266 use Catalyst qw/-Debug FormValidator Static OtherPlugin/;
268 You will also need to make sure your end method does I<not> forward
269 static content to the view, perhaps like this:
272 my ( $self, $c ) = @_;
274 $c->forward( 'MyApp::View::TT' )
275 unless ( $c->res->body || !$c->stash->{template} );
278 This code will only forward to the view if a template has been
279 previously defined by a controller and if there is not already data in
280 C<$c-E<gt>res-E<gt>body>.
282 Next, create a controller to handle requests for the /static path. Use
283 the Helper to save time. This command will create a stub controller as
284 C<lib/MyApp/Controller/Static.pm>.
286 $ script/myapp_create.pl controller Static
288 Edit the file and add the following methods:
290 # serve all files under /static as static files
291 sub default : Path('/static') {
292 my ( $self, $c ) = @_;
294 # Optional, allow the browser to cache the content
295 $c->res->headers->header( 'Cache-Control' => 'max-age=86400' );
297 $c->serve_static; # from Catalyst::Plugin::Static
300 # also handle requests for /favicon.ico
301 sub favicon : Path('/favicon.ico') {
302 my ( $self, $c ) = @_;
307 You can also define a different icon for the browser to use instead of
308 favicon.ico by using this in your HTML header:
310 <link rel="icon" href="/static/myapp.ico" type="image/x-icon" />
312 =head3 Common problems with the Static plugin
314 The Static plugin makes use of the C<shared-mime-info> package to
315 automatically determine MIME types. This package is notoriously
316 difficult to install, especially on win32 and OS X. For OS X the easiest
317 path might be to install Fink, then use C<apt-get install
318 shared-mime-info>. Restart the server, and everything should be fine.
320 Make sure you are using the latest version (>= 0.16) for best
321 results. If you are having errors serving CSS files, or if they get
322 served as text/plain instead of text/css, you may have an outdated
323 shared-mime-info version. You may also wish to simply use the following
324 code in your Static controller:
326 if ($c->req->path =~ /css$/i) {
327 $c->serve_static( "text/css" );
332 =head3 Serving Static Files with Apache
334 When using Apache, you can bypass Catalyst and any Static
335 plugins/controllers controller by intercepting requests for the
336 C<root/static> path at the server level. All that is required is to
337 define a DocumentRoot and add a separate Location block for your static
338 content. Here is a complete config for this application under mod_perl
342 use lib qw(/var/www/MyApp/lib);
347 ServerName myapp.example.com
348 DocumentRoot /var/www/MyApp/root
350 SetHandler perl-script
353 <LocationMatch "/(static|favicon.ico)">
354 SetHandler default-handler
358 And here's a simpler example that'll get you started:
360 Alias /static/ "/my/static/files/"
365 =head2 Forwarding with arguments
367 Sometimes you want to pass along arguments when forwarding to another
368 action. As of version 5.30, arguments can be passed in the call to
369 C<forward>; in earlier versions, you can manually set the arguments in
370 the Catalyst Request object:
372 # version 5.30 and later:
373 $c->forward('/wherever', [qw/arg1 arg2 arg3/]);
376 $c->req->args([qw/arg1 arg2 arg3/]);
377 $c->forward('/wherever');
379 (See the L<Catalyst::Manual::Intro> Flow_Control section for more
380 information on passing arguments via C<forward>.)
382 =head2 Configure your application
384 You configure your application with the C<config> method in your
385 application class. This can be hard-coded, or brought in from a
386 separate configuration file.
390 YAML is a method for creating flexible and readable configuration
391 files. It's a great way to keep your Catalyst application configuration
392 in one easy-to-understand location.
394 In your application class (e.g. C<lib/MyApp.pm>):
398 __PACKAGE__->config( YAML::LoadFile(__PACKAGE__->config->{'home'} . '/myapp.yml') );
401 Now create C<myapp.yml> in your application home:
404 # DO NOT USE TABS FOR INDENTATION OR label/value SEPARATION!!!
407 # session; perldoc Catalyst::Plugin::Session::FastMmap
411 storage: '/tmp/myapp.session'
413 # emails; perldoc Catalyst::Plugin::Email
414 # this passes options as an array :(
419 This is equivalent to:
421 # configure base package
422 __PACKAGE__->config( name => MyApp );
423 # configure authentication
424 __PACKAGE__->config->{authentication} = {
425 user_class => 'MyApp::Model::MyDB::Customer',
429 __PACKAGE__->config->{session} = {
433 # configure email sending
434 __PACKAGE__->config->{email} = [qw/SMTP localhost/];
438 =head2 Using existing DBIC (etc.) classes with Catalyst
440 Many people have existing Model classes that they would like to use with
441 Catalyst (or, conversely, they want to write Catalyst models that can be
442 used outside of Catalyst, e.g. in a cron job). It's trivial to write a
443 simple component in Catalyst that slurps in an outside Model:
445 package MyApp::Model::DB;
446 use base qw/Catalyst::Model::DBIC::Schema/;
448 schema_class => 'Some::DBIC::Schema',
449 connect_info => ['dbi:SQLite:foo.db', '', '', {AutoCommit=>1}];
453 and that's it! Now C<Some::DBIC::Schema> is part of your
454 Cat app as C<MyApp::Model::DB>.
456 =head2 Delivering a Custom Error Page
458 By default, Catalyst will display its own error page whenever it
459 encounters an error in your application. When running under C<-Debug>
460 mode, the error page is a useful screen including the error message and
461 L<Data::Dump> output of the relevant parts of the C<$c> context object.
462 When not in C<-Debug>, users see a simple "Please come back later" screen.
464 To use a custom error page, use a special C<end> method to short-circuit
465 the error processing. The following is an example; you might want to
466 adjust it further depending on the needs of your application (for
467 example, any calls to C<fillform> will probably need to go into this
468 C<end> method; see L<Catalyst::Plugin::FillInForm>).
471 my ( $self, $c ) = @_;
473 if ( scalar @{ $c->error } ) {
474 $c->stash->{errors} = $c->error;
475 $c->stash->{template} = 'errors.tt';
476 $c->forward('MyApp::View::TT');
480 return 1 if $c->response->status =~ /^3\d\d$/;
481 return 1 if $c->response->body;
483 unless ( $c->response->content_type ) {
484 $c->response->content_type('text/html; charset=utf-8');
487 $c->forward('MyApp::View::TT');
490 You can manually set errors in your code to trigger this page by calling
492 $c->error( 'You broke me!' );
494 =head2 Role-based Authorization
496 For more advanced access control, you may want to consider using role-based
497 authorization. This means you can assign different roles to each user, e.g.
498 "user", "admin", etc.
500 The C<login> and C<logout> methods and view template are exactly the same as
501 in the previous example.
503 The L<Catalyst::Plugin::Authorization::Roles> plugin is required when
508 Authentication::Credential::Password
509 Authentication::Store::Htpasswd
513 Roles are implemented automatically when using
514 L<Catalyst::Authentication::Store::Htpasswd>:
516 # no additional role configuration required
517 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
519 Or can be set up manually when using L<Catalyst::Authentication::Store::DBIC>:
521 # Authorization using a many-to-many role relationship
522 __PACKAGE__->config->{authorization}{dbic} = {
523 'role_class' => 'My::Model::DBIC::Role',
524 'role_field' => 'name',
525 'user_role_user_field' => 'user',
527 # DBIx::Class only (omit if using Class::DBI)
528 'role_rel' => 'user_role',
530 # Class::DBI only, (omit if using DBIx::Class)
531 'user_role_class' => 'My::Model::CDBI::UserRole'
532 'user_role_role_field' => 'role',
535 To restrict access to any action, you can use the C<check_user_roles> method:
537 sub restricted : Local {
538 my ( $self, $c ) = @_;
540 $c->detach("unauthorized")
541 unless $c->check_user_roles( "admin" );
543 # do something restricted here
546 You can also use the C<assert_user_roles> method. This just gives an error if
547 the current user does not have one of the required roles:
549 sub also_restricted : Global {
550 my ( $self, $c ) = @_;
551 $c->assert_user_roles( qw/ user admin / );
554 =head2 Quick deployment: Building PAR Packages
556 You have an application running on your development box, but then you
557 have to quickly move it to another one for
558 demonstration/deployment/testing...
560 PAR packages can save you from a lot of trouble here. They are usual Zip
561 files that contain a blib tree; you can even include all prereqs and a
562 perl interpreter by setting a few flags!
564 =head3 Follow these few points to try it out!
566 1. Install Catalyst and PAR 0.89 (or later)
568 % perl -MCPAN -e 'install Catalyst'
570 % perl -MCPAN -e 'install PAR'
573 2. Create a application
579 3. Add these lines to Makefile.PL (below "catalyst_files();")
581 catalyst_par_core(); # Include modules that are also included
582 # in the standard Perl distribution,
583 # this is optional but highly suggested
585 catalyst_par(); # Generate a PAR as soon as the blib
588 4. Prepare the Makefile, test your app, create a PAR (the two
589 Makefile.PL calls are no typo)
598 Recent versions of Catalyst include L<Module::Install::Catalyst>, which
599 simplifies the process greatly.
606 Congratulations! Your package "myapp.par" is ready, the following
607 steps are just optional.
609 5. Test your PAR package with "parl" (no typo)
613 [parl] myapp[.par] [script] [arguments]
616 parl myapp.par myapp_server.pl -r
626 % parl myapp.par myapp_server.pl
627 You can connect to your server at http://localhost:3000
629 Yes, this nifty little starter application gets automatically included.
630 You can also use "catalyst_par_script('myapp_server.pl')" to set a
631 default script to execute.
633 6. Want to create a binary that includes the Perl interpreter?
635 % pp -o myapp myapp.par
636 % ./myapp myapp_server.pl
637 You can connect to your server at http://localhost:3000
639 =head2 mod_perl Deployment
641 In today's entry, I'll be talking about deploying an application in
642 production using Apache and mod_perl.
646 mod_perl is the best solution for many applications, but I'll list some pros
647 and cons so you can decide for yourself. The other production deployment
648 option is FastCGI, which I'll talk about in a future calendar article.
654 mod_perl is very fast and your app will benefit from being loaded in memory
655 within each Apache process.
657 =head4 Shared memory for multiple apps
659 If you need to run several Catalyst apps on the same server, mod_perl will
660 share the memory for common modules.
666 Since your application is fully loaded in memory, every Apache process will
667 be rather large. This means a large Apache process will be tied up while
668 serving static files, large files, or dealing with slow clients. For this
669 reason, it is best to run a two-tiered web architecture with a lightweight
670 frontend server passing dynamic requests to a large backend mod_perl
675 Any changes made to the core code of your app require a full Apache restart.
676 Catalyst does not support Apache::Reload or StatINC. This is another good
677 reason to run a frontend web server where you can set up an
678 C<ErrorDocument 502> page to report that your app is down for maintenance.
680 =head4 Cannot run multiple versions of the same app
682 It is not possible to run two different versions of the same application in
683 the same Apache instance because the namespaces will collide.
687 Now that we have that out of the way, let's talk about setting up mod_perl
688 to run a Catalyst app.
690 =head4 1. Install Catalyst::Engine::Apache
692 You should install the latest versions of both Catalyst and
693 Catalyst::Engine::Apache. The Apache engines were separated from the
694 Catalyst core in version 5.50 to allow for updates to the engine without
695 requiring a new Catalyst release.
697 =head4 2. Install Apache with mod_perl
699 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
700 recommended. With Apache 2, make sure you are using the prefork MPM and not
701 the worker MPM. The reason for this is that many Perl modules are not
702 thread-safe and may have problems running within the threaded worker
703 environment. Catalyst is thread-safe however, so if you know what you're
704 doing, you may be able to run using worker.
706 In Debian, the following commands should get you going.
708 apt-get install apache2-mpm-prefork
709 apt-get install libapache2-mod-perl2
711 =head4 3. Configure your application
713 Every Catalyst application will automagically become a mod_perl handler
714 when run within mod_perl. This makes the configuration extremely easy.
715 Here is a basic Apache 2 configuration.
717 PerlSwitches -I/var/www/MyApp/lib
722 PerlResponseHandler MyApp
725 The most important line here is C<PerlModule MyApp>. This causes mod_perl
726 to preload your entire application into shared memory, including all of your
727 controller, model, and view classes and configuration. If you have -Debug
728 mode enabled, you will see the startup output scroll by when you first
731 For an example Apache 1.3 configuration, please see the documentation for
732 L<Catalyst::Engine::Apache::MP13>.
736 That's it, your app is now a full-fledged mod_perl application! Try it out
737 by going to http://your.server.com/.
741 =head4 Non-root location
743 You may not always want to run your app at the root of your server or virtual
744 host. In this case, it's a simple change to run at any non-root location
749 PerlResponseHandler MyApp
752 When running this way, it is best to make use of the C<uri_for> method in
753 Catalyst for constructing correct links.
755 =head4 Static file handling
757 Static files can be served directly by Apache for a performance boost.
759 DocumentRoot /var/www/MyApp/root
761 SetHandler default-handler
764 This will let all files within root/static be handled directly by Apache. In
765 a two-tiered setup, the frontend server should handle static files.
766 The configuration to do this on the frontend will vary.
768 =head2 Extending RenderView (formerly DefaultEnd)
770 The recommended approach for an C<end> action is to use
771 L<Catalyst::Action::RenderView> (taking the place of
772 L<Catalyst::Plugin::DefaultEnd>), which does what you usually need.
773 However there are times when you need to add a bit to it, but don't want
774 to write your own C<end> action.
776 You can extend it like this:
778 To add something to an C<end> action that is called before rendering
779 (this is likely to be what you want), simply place it in the C<end>
782 sub end : ActionClass('RenderView') {
783 my ( $self, $c ) = @_;
784 # do stuff here; the RenderView action is called afterwards
787 To add things to an C<end> action that are called I<after> rendering,
788 you can set it up like this:
790 sub render : ActionClass('RenderView') { }
793 my ( $self, $c ) = @_;
794 $c->forward('render');
798 =head2 Catalyst on shared hosting
800 So, you want to put your Catalyst app out there for the whole world to
801 see, but you don't want to break the bank. There is an answer - if you
802 can get shared hosting with FastCGI and a shell, you can install your
803 Catalyst app in a local directory on your shared host. First, run
807 and go through the standard CPAN configuration process. Then exit out
808 without installing anything. Next, open your .bashrc and add
810 export PATH=$HOME/local/bin:$HOME/local/script:$PATH
811 perlversion=`perl -v | grep 'built for' | awk '{print $4}' | sed -e 's/v//;'`
812 export PERL5LIB=$HOME/local/share/perl/$perlversion:$HOME/local/lib/perl/$perlversion:$HOME/local/lib:$PERL5LIB
814 and log out, then back in again (or run C<". .bashrc"> if you
815 prefer). Finally, edit C<.cpan/CPAN/MyConfig.pm> and add
817 'make_install_arg' => qq[SITEPREFIX=$ENV{HOME}/local],
818 'makepl_arg' => qq[INSTALLDIRS=site install_base=$ENV{HOME}/local],
820 Now you can install the modules you need using CPAN as normal; they
821 will be installed into your local directory, and perl will pick them
822 up. Finally, change directory into the root of your virtual host and
823 symlink your application's script directory in:
825 cd path/to/mydomain.com
826 ln -s ~/lib/MyApp/script script
828 And add the following lines to your .htaccess file (assuming the server
829 is setup to handle .pl as fcgi - you may need to rename the script to
830 myapp_fastcgi.fcgi and/or use a SetHandler directive):
833 RewriteCond %{REQUEST_URI} !^/?script/myapp_fastcgi.pl
834 RewriteRule ^(.*)$ script/myapp_fastcgi.pl/$1 [PT,L]
836 Now C<http://mydomain.com/> should now Just Work. Congratulations, now
837 you can tell your friends about your new website (or in our case, tell
838 the client it's time to pay the invoice :) )
842 Catalyst makes it easy to employ several different types of caching to
843 speed up your applications.
847 There are three wrapper plugins around common CPAN cache modules:
848 Cache::FastMmap, Cache::FileCache, and Cache::Memcached. These can be
849 used to cache the result of slow operations.
851 This very page you're viewing makes use of the FileCache plugin to cache the
852 rendered XHTML version of the source POD document. This is an ideal
853 application for a cache because the source document changes infrequently but
854 may be viewed many times.
856 use Catalyst qw/Cache::FileCache/;
861 sub render_pod : Local {
862 my ( self, $c ) = @_;
864 # the cache is keyed on the filename and the modification time
865 # to check for updates to the file.
866 my $file = $c->path_to( 'root', '2005', '11.pod' );
867 my $mtime = ( stat $file )->mtime;
869 my $cached_pod = $c->cache->get("$file $mtime");
870 if ( !$cached_pod ) {
871 $cached_pod = do_slow_pod_rendering();
872 # cache the result for 12 hours
873 $c->cache->set( "$file $mtime", $cached_pod, '12h' );
875 $c->stash->{pod} = $cached_pod;
878 We could actually cache the result forever, but using a value such as 12 hours
879 allows old entries to be automatically expired when they are no longer needed.
883 Another method of caching is to cache the entire HTML page. While this is
884 traditionally handled by a front-end proxy server like Squid, the Catalyst
885 PageCache plugin makes it trivial to cache the entire output from
886 frequently-used or slow actions.
888 Many sites have a busy content-filled front page that might look something
889 like this. It probably takes a while to process, and will do the exact same
890 thing for every single user who views the page.
892 sub front_page : Path('/') {
893 my ( $self, $c ) = @_;
895 $c->forward( 'get_news_articles' );
896 $c->forward( 'build_lots_of_boxes' );
897 $c->forward( 'more_slow_stuff' );
899 $c->stash->{template} = 'index.tt';
902 We can add the PageCache plugin to speed things up.
904 use Catalyst qw/Cache::FileCache PageCache/;
906 sub front_page : Path ('/') {
907 my ( $self, $c ) = @_;
909 $c->cache_page( 300 );
911 # same processing as above
914 Now the entire output of the front page, from <html> to </html>, will be
915 cached for 5 minutes. After 5 minutes, the next request will rebuild the
916 page and it will be re-cached.
918 Note that the page cache is keyed on the page URI plus all parameters, so
919 requests for / and /?foo=bar will result in different cache items. Also,
920 only GET requests will be cached by the plugin.
922 You can even get that front-end Squid proxy to help out by enabling HTTP
923 headers for the cached page.
925 MyApp->config->{page_cache}->{set_http_headers} = 1;
927 This would now set the following headers so proxies and browsers may cache
928 the content themselves.
930 Cache-Control: max-age=($expire_time - time)
931 Expires: $expire_time
932 Last-Modified: $cache_created_time
934 =head3 Template Caching
936 Template Toolkit provides support for caching compiled versions of your
937 templates. To enable this in Catalyst, use the following configuration.
938 TT will cache compiled templates keyed on the file mtime, so changes will
939 still be automatically detected.
941 package MyApp::View::TT;
945 use base 'Catalyst::View::TT';
948 COMPILE_DIR => '/tmp/template_cache',
955 See the documentation for each cache plugin for more details and other
956 available configuration options.
958 L<Catalyst::Plugin::Cache::FastMmap>
959 L<Catalyst::Plugin::Cache::FileCache>
960 L<Catalyst::Plugin::Cache::Memcached>
961 L<Catalyst::Plugin::PageCache>
962 L<http://search.cpan.org/dist/Template-Toolkit/lib/Template/Manual/Config.pod#Caching_and_Compiling_Options>
964 =head2 Component-based Subrequests
966 See L<Catalyst::Plugin::SubRequest>.
968 =head2 DBIx::Class as a Catalyst Model
970 See L<Catalyst::Model::DBIC::Schema>.
972 =head2 Authentication/Authorization
974 This is done in several steps:
980 Getting the user to identify themselves, by giving you some piece of
981 information known only to you and the user. Then you can assume that the user
982 is who they say they are. This is called B<credential verification>.
986 Making sure the user only accesses functions you want them to access. This is
987 done by checking the verified users data against your internal list of groups,
988 or allowed persons for the current page.
994 The Catalyst Authentication system is made up of many interacting modules, to
995 give you the most flexibility possible.
997 =head4 Credential verifiers
999 A Credential module tables the user input, and passes it to a Store, or some
1000 other system, for verification. Typically, a user object is created by either
1001 this module or the Store and made accessible by a C<< $c->user >> call.
1005 Password - Simple username/password checking.
1006 HTTPD - Checks using basic HTTP auth.
1007 TypeKey - Check using the typekey system.
1009 =head3 Storage backends
1011 A Storage backend contains the actual data representing the users. It is
1012 queried by the credential verifiers. Updating the store is not done within
1013 this system, you will need to do it yourself.
1017 DBIC - Storage using a database.
1018 Minimal - Storage using a simple hash (for testing).
1022 A User object is created by either the storage backend or the credential
1023 verifier, and filled with the retrieved user information.
1027 Hash - A simple hash of keys and values.
1029 =head3 ACL authorization
1031 ACL stands for Access Control List. The ACL plugin allows you to regulate
1032 access on a path by path basis, by listing which users, or roles, have access
1035 =head3 Roles authorization
1037 Authorization by roles is for assigning users to groups, which can then be
1038 assigned to ACLs, or just checked when needed.
1042 When you have chosen your modules, all you need to do is call the C<<
1043 $c->login >> method. If called with no parameters, it will try to find
1044 suitable parameters, such as B<username> and B<password>, or you can pass it
1047 =head3 Checking roles
1049 Role checking is done by using the C<< $c->check_user_roles >> method, this will
1050 check using the currently logged in user (via C<< $c->user >>). You pass it
1051 the name of a role to check, and it returns true if the user is a member.
1055 use Catalyst qw/Authentication
1056 Authentication::Credential::Password
1057 Authentication::Store::Htpasswd
1058 Authorization::Roles/;
1060 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
1063 my ($self, $c) = @_;
1065 if ( my $user = $c->req->param("user")
1066 and my $password = $c->req->param("password") )
1068 if ( $c->login( $user, $password ) ) {
1069 $c->res->body( "hello " . $c->user->name );
1075 # invalid form input
1079 sub restricted : Local {
1080 my ( $self, $c ) = @_;
1082 $c->detach("unauthorized")
1083 unless $c->check_user_roles( "admin" );
1085 # do something restricted here
1088 =head3 Using authentication in a testing environment
1090 Ideally, to write tests for authentication/authorization code one would first
1091 set up a test database with known data, then use
1092 L<Test::WWW::Mechanize::Catalyst> to simulate a user logging in. Unfortunately
1093 the former can be rather awkward, which is why it's a good thing that the
1094 authentication framework is so flexible.
1096 Instead of using a test database, one can simply change the authentication
1097 store to something a bit easier to deal with in a testing
1098 environment. Additionally, this has the advantage of not modifying one's
1099 database, which can be problematic if one forgets to use the testing instead of
1100 production database.
1104 use Catalyst::Plugin::Authentication::Store::Minimal::Backend;
1106 # Sets up the user `test_user' with password `test_pass'
1107 MyApp->default_auth_store(
1108 Catalyst::Plugin::Authentication::Store::Minimal::Backend->new({
1109 test_user => { password => 'test_pass' },
1113 Now, your test code can call C<$c->login('test_user', 'test_pass')> and
1114 successfully login, without messing with the database at all.
1116 =head3 More information
1118 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authentication> has a longer explanation.
1122 When you have your users identified, you will want to somehow remember that
1123 fact, to save them from having to identify themselves for every single
1124 page. One way to do this is to send the username and password parameters in
1125 every single page, but that's ugly, and won't work for static pages.
1127 Sessions are a method of saving data related to some transaction, and giving
1128 the whole collection a single ID. This ID is then given to the user to return
1129 to us on every page they visit while logged in. The usual way to do this is
1130 using a browser cookie.
1132 Catalyst uses two types of plugins to represent sessions:
1136 A State module is used to keep track of the state of the session between the
1137 users browser, and your application.
1139 A common example is the Cookie state module, which sends the browser a cookie
1140 containing the session ID. It will use default value for the cookie name and
1141 domain, so will "just work" when used.
1145 A Store module is used to hold all the data relating to your session, for
1146 example the users ID, or the items for their shopping cart. You can store data
1147 in memory (FastMmap), in a file (File) or in a database (DBI).
1149 =head3 Authentication magic
1151 If you have included the session modules in your application, the
1152 Authentication modules will automagically use your session to save and
1153 retrieve the user data for you.
1155 =head3 Using a session
1157 Once the session modules are loaded, the session is available as C<<
1158 $c->session >>, and can be writen to and read from as a simple hash reference.
1164 Session::Store::FastMmap
1165 Session::State::Cookie
1169 ## Write data into the session
1171 sub add_item : Local {
1172 my ( $self, $c ) = @_;
1174 my $item_id = $c->req->param("item");
1176 push @{ $c->session->{items} }, $item_id;
1180 ## A page later we retrieve the data from the session:
1182 sub get_items : Local {
1183 my ( $self, $c ) = @_;
1185 $c->stash->{items_to_display} = $c->session->{items};
1190 =head3 More information
1192 L<http://search.cpan.org/dist/Catalyst-Plugin-Session>
1194 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-Cookie>
1196 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-URI>
1198 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-FastMmap>
1200 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-File>
1202 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-DBI>
1204 =head2 Adding RSS feeds
1206 Adding RSS feeds to your stuff in Catalyst is really simple. I'll show two
1207 different aproaches here, but the basic premise is that you forward to the
1208 normal view action first to get the objects, then handle the output differently
1210 =head3 Using TT templates
1212 This is the aproach we chose in Agave (L<http://dev.rawmode.org/>).
1216 $c->forward('view');
1217 $c->stash->{template}='rss.tt';
1220 Then you need a template. Here's the one from Agave:
1221 L<http://svn.rawmode.org/repos/Agave/trunk/root/base/blog/rss.tt>
1223 As you can see, it's pretty simple.
1225 =head3 Using XML::Feed
1227 However, a more robust solution is to use XML::Feed, as we've done in this
1228 Advent Calendar. Assuming we have a 'view' action that populates 'entries'
1229 with some DBIx::Class/Class::DBI iterator, the code would look something like
1234 $c->forward('view'); # get the entries
1236 my $feed = XML::Feed->new('RSS');
1237 $feed->title( $c->config->{name} . ' RSS Feed' );
1238 $feed->link( $c->req->base ); # link to the site.
1239 $feed->description('Catalyst advent calendar'); Some description
1241 # Process the entries
1242 while( my $entry=$c->stash->{entries}->next ) {
1243 my $feed_entry = XML::Feed::Entry->new('RSS');
1244 $feed_entry->title($entry->title);
1245 $feed_entry->link( $c->uri_for($entry->link) );
1246 $feed_entry->issued( DateTime->from_epoch(epoch => $entry->created) );
1247 $feed->add_entry($feed_entry);
1249 $c->res->body( $feed->as_xml );
1253 A little more code in the controller, but with this approach you're pretty sure
1254 to get something that validates. One little note regarding that tho, for both
1255 of the above aproaches, you'll need to set the content type like this:
1257 $c->res->content_type('application/rss+xml');
1261 Note that you could generalize the second variant easily by replacing 'RSS'
1262 with a variable, so you can generate Atom feeds with the same code.
1264 Now, go ahead and make RSS feeds for all your stuff. The world *needs* updates
1267 =head2 FastCGI Deployment
1269 As a companion to Day 7's mod_perl article, today's article is about
1270 production FastCGI deployment.
1276 FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you;
1277 your app runs as multiple persistent processes ready to receive connections
1278 from the web server.
1282 When using external FastCGI servers, your application runs as a standalone
1283 application server. It may be restarted independently from the web server.
1284 This allows for a more robust environment and faster reload times when
1285 pushing new app changes. The frontend server can even be configured to
1286 display a friendly "down for maintenance" page while the application is
1289 =head4 Load-balancing
1291 You can launch your application on multiple backend servers and allow the
1292 frontend web server to load-balance between all of them. And of course, if
1293 one goes down, your app continues to run fine.
1295 =head4 Multiple versions of the same app
1297 Each FastCGI application is a separate process, so you can run different
1298 versions of the same app on a single server.
1300 =head4 Can run with threaded Apache
1302 Since your app is not running inside of Apache, the faster mpm_worker module
1303 can be used without worrying about the thread safety of your application.
1307 =head4 More complex environment
1309 With FastCGI, there are more things to monitor and more processes running
1310 than when using mod_perl.
1314 =head4 1. Install Apache with mod_fastcgi
1316 mod_fastcgi for Apache is a third party module, and can be found at
1317 L<http://www.fastcgi.com/>. It is also packaged in many distributions, for
1318 example, libapache2-mod-fastcgi in Debian.
1320 =head4 2. Configure your application
1322 # Serve static content directly
1323 DocumentRoot /var/www/MyApp/root
1324 Alias /static /var/www/MyApp/root/static
1326 FastCgiServer /var/www/MyApp/script/myapp_fastcgi.pl -processes 3
1327 Alias /myapp/ /var/www/MyApp/script/myapp_fastcgi.pl/
1329 # Or, run at the root
1330 Alias / /var/www/MyApp/script/myapp_fastcgi.pl/
1332 The above commands will launch 3 app processes and make the app available at
1335 =head3 Standalone server mode
1337 While not as easy as the previous method, running your app as an external
1338 server gives you much more flexibility.
1340 First, launch your app as a standalone server listening on a socket.
1342 script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5 -p /tmp/myapp.pid -d
1344 You can also listen on a TCP port if your web server is not on the same
1347 script/myapp_fastcgi.pl -l :8080 -n 5 -p /tmp/myapp.pid -d
1349 You will probably want to write an init script to handle starting/stopping
1350 of the app using the pid file.
1352 Now, we simply configure Apache to connect to the running server.
1354 # 502 is a Bad Gateway error, and will occur if the backend server is down
1355 # This allows us to display a friendly static page that says "down for
1357 Alias /_errors /var/www/MyApp/root/error-pages
1358 ErrorDocument 502 /_errors/502.html
1360 FastCgiExternalServer /tmp/myapp -socket /tmp/myapp.socket
1361 Alias /myapp/ /tmp/myapp/
1363 # Or, run at the root
1368 Lots more information is available in the new and expanded FastCGI docs that
1369 will be part of Catalyst 5.62. For now you may read them here:
1370 L<http://dev.catalyst.perl.org/file/trunk/Catalyst/lib/Catalyst/Engine/FastCGI.pm>
1372 =head2 Catalyst::View::TT
1374 One of the first things you probably want to do when starting a new Catalyst application is set up your View. Catalyst doesn't care how you display your data; you can choose to generate HTML, PDF files, or plain text if you wanted.
1376 Most Catalyst applications use a template system to generate their HTML, and though there are several template systems available, Template Toolkit is probably the most popular.
1378 Once again, the Catalyst developers have done all the hard work, and made things easy for the rest of us. Catalyst::View::TT provides the interface to Template Toolkit, and provides Helpers which let us set it up that much more easily.
1380 =head3 Creating your View
1382 Catalyst::View::TT provides two different helpers for use to use: TT and TTSite.
1386 Create a basic Template Toolkit View using the provided helper script:
1388 script/myapp_create.pl view TT TT
1390 This will create lib/MyApp/View/MyView.pm, which is going to be pretty empty to start. However, it sets everything up that you need to get started. You can now define which template you want and forward to your view. For instance:
1393 my ( $self, $c ) = @_;
1395 $c->stash->{template} = 'hello.tt';
1397 $c->forward( $c->view('TT') );
1400 In most cases, you will put the $c->forward into end(), and then you would only have to define which template you want to use. The S<DefaultEnd> plugin discussed on Day 8 is also commonly used.
1404 Although the TT helper does create a functional, working view, you may find yourself having to create the same template files and changing the same options every time you create a new application. The TTSite helper saves us even more time by creating the basic templates and setting some common options for us.
1406 Once again, you can use the helper script:
1408 script/myapp_create.pl view TT TTSite
1410 This time, the helper sets several options for us in the generated View.
1412 __PACKAGE__->config({
1413 CATALYST_VAR => 'Catalyst',
1415 MyApp->path_to( 'root', 'src' ),
1416 MyApp->path_to( 'root', 'lib' )
1418 PRE_PROCESS => 'config/main',
1419 WRAPPER => 'site/wrapper',
1420 ERROR => 'error.tt2',
1427 INCLUDE_PATH defines the directories that Template Toolkit should search for the template files.
1430 PRE_PROCESS is used to process configuration options which are common to every template file.
1433 WRAPPER is a file which is processed with each template, usually used to easily provide a common header and footer for every page.
1437 In addition to setting these options, the TTSite helper also created the template and config files for us! In the 'root' directory, you'll notice two new directories: src and lib.
1439 Several configuration files in root/lib/config are called by PRE_PROCESS.
1441 The files in root/lib/site are the site-wide templates, called by WRAPPER, and display the html framework, control the layout, and provide the templates for the header and footer of your page. Using the template organization provided makes it much easier to standardize pages and make changes when they are (inevitably) needed.
1443 The template files that you will create for your application will go into root/src, and you don't need to worry about putting the the <html> or <head> sections; just put in the content. The WRAPPER will the rest of the page around your template for you.
1447 Of course, having the template system include the header and footer for you isn't all that we want our templates to do. We need to be able to put data into our templates, and have it appear where and how we want it, right? That's where the stash comes in.
1449 In our controllers, we can add data to the stash, and then access it from the template. For instance:
1452 my ( $self, $c ) = @_;
1454 $c->stash->{name} = 'Adam';
1456 $c->stash->{template} = 'hello.tt';
1458 $c->forward( $c->view('TT') );
1463 <strong>Hello, [% name %]!</strong>
1465 When you view this page, it will display "Hello, Adam!"
1467 All of the information in your stash is available, by its name/key, in your templates. And your data doesn't have to be plain, old, boring scalars. You can pass array references and hash references, too.
1472 my ( $self, $c ) = @_;
1474 $c->stash->{names} = [ 'Adam', 'Dave', 'John' ];
1476 $c->stash->{template} = 'hello.tt';
1478 $c->forward( $c->view('TT') );
1483 [% FOREACH name IN names %]
1484 <strong>Hello, [% name %]!</strong><br />
1487 This allowed us to loop through each item in the arrayref, and display a line for each name that we have.
1489 This is the most basic usage, but Template Toolkit is quite powerful, and allows you to truly keep your presentation logic separate from the rest of your application.
1491 =head3 $c->uri_for()
1493 One of my favorite things about Catalyst is the ability to move an application around without having to worry that everything is going to break. One of the areas that used to be a problem was with the http links in your template files. For example, suppose you have an application installed at http://www.domain.com/Calendar. The links point to "/Calendar", "/Calendar/2005", "/Calendar/2005/10", etc. If you move the application to be at http://www.mydomain.com/Tools/Calendar, then all of those links will suddenly break.
1495 That's where $c->uri_for() comes in. This function will merge its parameters with either the base location for the app, or its current namespace. Let's take a look at a couple of examples.
1497 In your template, you can use the following:
1499 <a href="[% c.uri_for('/login') %]">Login Here</a>
1501 Although the parameter starts with a forward slash, this is relative to the application root, not the webserver root. This is important to remember. So, if your application is installed at http://www.domain.com/Calendar, then the link would be http://www.mydomain.com/Calendar/Login. If you move your application to a different domain or path, then that link will still be correct.
1505 <a href="[% c.uri_for('2005','10', '24') %]">October, 24 2005</a>
1507 The first parameter does NOT have a forward slash, and so it will be relative to the current namespace. If the application is installed at http://www.domain.com/Calendar. and if the template is called from MyApp::Controller::Display, then the link would become http://www.domain.com/Calendar/Display/2005/10/24.
1509 Once again, this allows you to move your application around without having to worry about broken links. But there's something else, as well. Since the links are generated by uri_for, you can use the same template file by several different controllers, and each controller will get the links that its supposed to. Since we believe in Don't Repeat Yourself, this is particularly helpful if you have common elements in your site that you want to keep in one file.
1513 L<http://search.cpan.org/perldoc?Catalyst>
1515 L<http://search.cpan.org/perldoc?Catalyst%3A%3AView%3A%3ATT>
1517 L<http://search.cpan.org/perldoc?Template>
1521 Catalyst provides a convenient way of testing your application during
1522 development and before deployment in a real environment.
1524 C<Catalyst::Test> makes it possible to run the same tests both locally
1525 (without an external daemon) and against a remote server via HTTP.
1529 Let's examine a skeleton application's C<t/> directory:
1531 mundus:~/MyApp chansen$ ls -l t/
1533 -rw-r--r-- 1 chansen chansen 95 18 Dec 20:50 01app.t
1534 -rw-r--r-- 1 chansen chansen 190 18 Dec 20:50 02pod.t
1535 -rw-r--r-- 1 chansen chansen 213 18 Dec 20:50 03podcoverage.t
1541 Verifies that the application loads, compiles, and returns a successful
1546 Verifies that all POD is free from errors. Only executed if the C<TEST_POD>
1547 environment variable is true.
1549 =item C<03podcoverage.t>
1551 Verifies that all methods/functions have POD coverage. Only executed if the
1552 C<TEST_POD> environment variable is true.
1556 =head3 Creating tests
1558 mundus:~/MyApp chansen$ cat t/01app.t | perl -ne 'printf( "%2d %s", $., $_ )'
1559 1 use Test::More tests => 2;
1560 2 use_ok( Catalyst::Test, 'MyApp' );
1562 4 ok( request('/')->is_success );
1564 The first line declares how many tests we are going to run, in this case
1565 two. The second line tests and loads our application in test mode. The
1566 fourth line verifies that our application returns a successful response.
1568 C<Catalyst::Test> exports two functions, C<request> and C<get>. Each can
1569 take three different arguments:
1573 =item A string which is a relative or absolute URI.
1575 request('/my/path');
1576 request('http://www.host.com/my/path');
1578 =item An instance of C<URI>.
1580 request( URI->new('http://www.host.com/my/path') );
1582 =item An instance of C<HTTP::Request>.
1584 request( HTTP::Request->new( GET => 'http://www.host.com/my/path') );
1588 C<request> returns an instance of C<HTTP::Response> and C<get> returns the
1589 content (body) of the response.
1591 =head3 Running tests locally
1593 mundus:~/MyApp chansen$ CATALYST_DEBUG=0 TEST_POD=1 prove --lib lib/ t/
1594 t/01app............ok
1595 t/02pod............ok
1596 t/03podcoverage....ok
1597 All tests successful.
1598 Files=3, Tests=4, 2 wallclock secs ( 1.60 cusr + 0.36 csys = 1.96 CPU)
1600 C<CATALYST_DEBUG=0> ensures that debugging is off; if it's enabled you
1601 will see debug logs between tests.
1603 C<TEST_POD=1> enables POD checking and coverage.
1605 C<prove> A command-line tool that makes it easy to run tests. You can
1606 find out more about it from the links below.
1608 =head3 Running tests remotely
1610 mundus:~/MyApp chansen$ CATALYST_SERVER=http://localhost:3000/ prove --lib lib/ t/01app.t
1612 All tests successful.
1613 Files=1, Tests=2, 0 wallclock secs ( 0.40 cusr + 0.01 csys = 0.41 CPU)
1615 C<CATALYST_SERVER=http://localhost:3000/> is the absolute deployment URI of
1616 your application. In C<CGI> or C<FastCGI> it should be the host and path
1619 =head3 C<Test::WWW::Mechanize> and Catalyst
1621 Be sure to check out C<Test::WWW::Mechanize::Catalyst>. It makes it easy to
1622 test HTML, forms and links. A short example of usage:
1624 use Test::More tests => 6;
1625 use_ok( Test::WWW::Mechanize::Catalyst, 'MyApp' );
1627 my $mech = Test::WWW::Mechanize::Catalyst->new;
1628 $mech->get_ok("http://localhost/", 'Got index page');
1629 $mech->title_like( qr/^MyApp on Catalyst/, 'Got right index title' );
1630 ok( $mech->find_link( text_regex => qr/^Wiki/i ), 'Found link to Wiki' );
1631 ok( $mech->find_link( text_regex => qr/^Mailing-List/i ), 'Found link to Mailing-List' );
1632 ok( $mech->find_link( text_regex => qr/^IRC channel/i ), 'Found link to IRC channel' );
1634 =head3 Further Reading
1638 =item Catalyst::Test
1640 L<http://search.cpan.org/dist/Catalyst/lib/Catalyst/Test.pm>
1642 =item Test::WWW::Mechanize::Catalyst
1644 L<http://search.cpan.org/dist/Test-WWW-Mechanize-Catalyst/lib/Test/WWW/Mechanize/Catalyst.pm>
1646 =item Test::WWW::Mechanize
1648 L<http://search.cpan.org/dist/Test-WWW-Mechanize/Mechanize.pm>
1650 =item WWW::Mechanize
1652 L<http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm>
1654 =item LWP::UserAgent
1656 L<http://search.cpan.org/dist/libwww-perl/lib/LWP/UserAgent.pm>
1660 L<http://search.cpan.org/dist/libwww-perl/lib/HTML/Form.pm>
1664 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Message.pm>
1668 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request.pm>
1670 =item HTTP::Request::Common
1672 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request/Common.pm>
1674 =item HTTP::Response
1676 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Response.pm>
1680 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Status.pm>
1684 L<http://search.cpan.org/dist/URI/URI.pm>
1688 L<http://search.cpan.org/dist/Test-Simple/lib/Test/More.pm>
1692 L<http://search.cpan.org/dist/Test-Pod/Pod.pm>
1694 =item Test::Pod::Coverage
1696 L<http://search.cpan.org/dist/Test-Pod-Coverage/Coverage.pm>
1698 =item prove (Test::Harness)
1700 L<http://search.cpan.org/dist/Test-Harness/bin/prove>
1706 Today we'll discover the wonderful world of web services.
1707 XMLRPC is unlike SOAP a very simple (and imo elegant) protocol,
1708 exchanging small XML messages like these.
1713 TE: deflate,gzip;q=0.3
1714 Connection: TE, close
1717 Host: 127.0.0.1:3000
1718 User-Agent: SOAP::Lite/Perl/0.60
1720 Content-Type: text/xml
1722 <?xml version="1.0" encoding="UTF-8"?>
1724 <methodName>add</methodName>
1726 <param><value><int>1</int></value></param>
1727 <param><value><int>2</int></value></param>
1734 Date: Tue, 20 Dec 2005 07:45:55 GMT
1736 Content-Type: text/xml
1740 <?xml version="1.0" encoding="us-ascii"?>
1743 <param><value><int>3</int></value></param>
1747 Sweet little protocol, isn't it? :)
1749 Now follow these few steps to implement the application.
1751 1. Install Catalyst (5.61 or later), Catalyst::Plugin::XMLRPC (0.06 or later) and SOAP::Lite (for XMLRPCsh.pl)
1753 % perl -MCPAN -e'install Catalyst'
1755 % perl -MCPAN -e'install Catalyst::Plugin::XMLRPC'
1764 3. Add the XMLRPC plugin to MyApp.pm
1766 use Catalyst qw/-Debug Static::Simple XMLRPC/;
1768 4. Add a api controller
1770 % ./script/myapp_create.pl controller API
1772 5. Add a XMLRPC redispatch method and a add method with Remote attribute
1773 to lib/MyApp/Controller/API.pm
1775 sub default : Private {
1776 my ( $self, $c ) = @_;
1781 my ( $self, $c, $a, $b ) = @_;
1785 The default action is the entry point for each XMLRPC request, it will
1786 redispatch every request to methods with Remote attribute in the same class.
1788 The add method is no traditional action, it has no private or public path.
1789 Only the XMLRPC dispatcher knows it exists.
1791 6. Thats it! You have built your first web service, lets test it with
1792 XMLRPCsh.pl (part of SOAP::Lite)
1794 % ./script/myapp_server.pl
1796 % XMLRPCsh.pl http://127.0.0.1:3000/api
1797 Usage: method[(parameters)]
1799 --- XMLRPC RESULT ---
1802 =head3 Tip Of The Day
1804 Your return data type is usually auto-detected, but you can easily
1805 enforce a specific one.
1808 my ( $self, $c, $a, $b ) = @_;
1809 return RPC::XML::int->new( $a + $b );
1816 A Catalyst application is driven by one or more Controller modules. There are
1817 a number of ways that Catalyst can decide which of the methods in your
1818 controller modules it should call. Controller methods are also called actions,
1819 because they determine how your catalyst application should (re-)act to any
1820 given URL. When the application is started up, catalyst looks at all your
1821 actions, and decides which URLs they map to.
1823 =head3 Type attributes
1825 Each action is a normal method in your controller, except that it has an
1826 L<attribute|http://search.cpan.org/~nwclark/perl-5.8.7/lib/attributes.pm>
1827 attached. These can be one of several types.
1829 Assume our Controller module starts with the following package declaration:
1831 package MyApp::Controller::Buckets;
1833 and we are running our application on localhost, port 3000 (the test server default).
1839 A Path attribute also takes an argument, this can be either a relative or an
1840 absolute path. A relative path will be relative to the controller namespace,
1841 an absolute path will represent an exact matching URL.
1843 sub my_handles : Path('handles') { .. }
1847 http://localhost:3000/buckets/handles
1851 sub my_handles : Path('/handles') { .. }
1855 http://localhost:3000/handles
1859 When using a Local attribute, no parameters are needed, instead, the name of
1860 the action is matched in the URL. The namespaces created by the name of the
1861 controller package is always part of the URL.
1863 sub my_handles : Local { .. }
1867 http://localhost:3000/buckets/my_handles
1871 A Global attribute is similar to a Local attribute, except that the namespace
1872 of the controller is ignored, and matching starts at root.
1874 sub my_handles : Global { .. }
1878 http://localhost:3000/my_handles
1882 By now you should have figured that a Regex attribute is just what it sounds
1883 like. This one takes a regular expression, and matches starting from
1884 root. These differ from the rest as they can match multiple URLs.
1886 sub my_handles : Regex('^handles') { .. }
1890 http://localhost:3000/handles
1894 http://localhost:3000/handles_and_other_parts
1900 A LocalRegex is similar to a Regex, except it only matches below the current
1901 controller namespace.
1903 sub my_handles : LocalRegex(^handles') { .. }
1907 http://localhost:3000/buckets/handles
1911 http://localhost:3000/buckets/handles_and_other_parts
1917 Last but not least, there is the Private attribute, which allows you to create
1918 your own internal actions, which can be forwarded to, but won't be matched as
1921 sub my_handles : Private { .. }
1923 becomes nothing at all..
1925 Catalyst also predefines some special Private actions, which you can override,
1932 The default action will be called, if no other matching action is found. If
1933 you don't have one of these in your namespace, or any sub part of your
1934 namespace, you'll get an error page instead. If you want to find out where it
1935 was the user was trying to go, you can look in the request object using
1936 C<< $c->req->path >>.
1938 sub default : Private { .. }
1940 works for all unknown URLs, in this controller namespace, or every one if put
1941 directly into MyApp.pm.
1945 The index action is called when someone tries to visit the exact namespace of
1946 your controller. If index, default and matching Path actions are defined, then
1947 index will be used instead of default and Path.
1949 sub index : Private { .. }
1953 http://localhost:3000/buckets
1957 The begin action is called at the beginning of every request involving this
1958 namespace directly, before other matching actions are called. It can be used
1959 to set up variables/data for this particular part of your app. A single begin
1960 action is called, its always the one most relevant to the current namespace.
1962 sub begin : Private { .. }
1966 http://localhost:3000/bucket/(anything)?
1972 Like begin, this action is always called for the namespace it is in, after
1973 every other action has finished. It is commonly used to forward processing to
1974 the View component. A single end action is called, its always the one most
1975 relevant to the current namespace.
1978 sub end : Private { .. }
1980 is called once after any actions when
1982 http://localhost:3000/bucket/(anything)?
1988 Lastly, the auto action is magic in that B<every> auto action in
1989 the chain of paths up to and including the ending namespace, will be
1990 called. (In contrast, only one of the begin/end/default actions will be
1991 called, the relevant one).
1994 sub auto : Private { .. }
1998 sub auto : Private { .. }
2000 will both be called when visiting
2002 http://localhost:3000/bucket/(anything)?
2008 =head3 A word of warning
2010 Due to possible namespace conflicts with Plugins, it is advised to only put the
2011 pre-defined Private actions in your main MyApp.pm file, all others should go
2012 in a Controller module.
2014 =head3 More Information
2016 L<http://search.cpan.org/author/SRI/Catalyst-5.61/lib/Catalyst/Manual/Intro.pod>
2018 L<http://dev.catalyst.perl.org/wiki/FlowChart>
2021 =head2 Authorization
2025 Authorization is the step that comes after authentication. Authentication
2026 establishes that the user agent is really representing the user we think it's
2027 representing, and then authorization determines what this user is allowed to
2030 =head3 Role Based Access Control
2032 Under role based access control each user is allowed to perform any number of
2033 roles. For example, at a zoo no one but specially trained personnel can enter
2034 the moose cage (Mynd you, møøse bites kan be pretty nasti!). For example:
2036 package Zoo::Controller::MooseCage;
2038 sub feed_moose : Local {
2039 my ( $self, $c ) = @_;
2041 $c->model( "Moose" )->eat( $c->req->param("food") );
2044 With this action, anyone can just come into the moose cage and feed the moose,
2045 which is a very dangerous thing. We need to restrict this action, so that only
2046 a qualified moose feeder can perform that action.
2048 The Authorization::Roles plugin let's us perform role based access control
2049 checks. Let's load it:
2052 Authentication # yadda yadda
2053 Authorization::Roles
2056 And now our action should look like this:
2058 sub feed_moose : Local {
2059 my ( $self, $c ) = @_;
2061 if ( $c->check_roles( "moose_feeder" ) ) {
2062 $c->model( "Moose" )->eat( $c->req->param("food") );
2064 $c->stash->{error} = "unauthorized";
2068 This checks C<< $c->user >>, and only if the user has B<all> the roles in the
2069 list, a true value is returned.
2071 C<check_roles> has a sister method, C<assert_roles>, which throws an exception
2072 if any roles are missing.
2074 Some roles that might actually make sense in, say, a forum application:
2088 each with a distinct task (system administration versus content administration).
2090 =head3 Access Control Lists
2092 Checking for roles all the time can be tedious and error prone.
2094 The Authorization::ACL plugin let's us declare where we'd like checks to be
2095 done automatically for us.
2097 For example, we may want to completely block out anyone who isn't a
2098 C<moose_feeder> from the entire C<MooseCage> controller:
2100 Zoo->deny_access_unless( "/moose_cage", [qw/moose_feeder/] );
2102 The role list behaves in the same way as C<check_roles>. However, the ACL
2103 plugin isn't limited to just interacting with the Roles plugin. We can use a
2104 code reference instead. For example, to allow either moose trainers or moose
2105 feeders into the moose cage, we can create a more complex check:
2107 Zoo->deny_access_unless( "/moose_cage", sub {
2109 $c->check_roles( "moose_trainer" ) || $c->check_roles( "moose_feeder" );
2112 The more specific a role, the earlier it will be checked. Let's say moose
2113 feeders are now restricted to only the C<feed_moose> action, while moose
2114 trainers get access everywhere:
2116 Zoo->deny_access_unless( "/moose_cage", [qw/moose_trainer/] );
2117 Zoo->allow_access_if( "/moose_cage/feed_moose", [qw/moose_feeder/]);
2119 When the C<feed_moose> action is accessed the second check will be made. If the
2120 user is a C<moose_feeder>, then access will be immediately granted. Otherwise,
2121 the next rule in line will be tested - the one checking for a C<moose_trainer>.
2122 If this rule is not satisfied, access will be immediately denied.
2124 Rules applied to the same path will be checked in the order they were added.
2126 Lastly, handling access denial events is done by creating an C<access_denied>
2129 sub access_denied : Private {
2130 my ( $self, $c, $action ) = @_;
2135 This action works much like auto, in that it is inherited across namespaces
2136 (not like object oriented code). This means that the C<access_denied> action
2137 which is B<nearest> to the action which was blocked will be triggered.
2139 If this action does not exist, an error will be thrown, which you can clean up
2140 in your C<end> private action instead.
2142 Also, it's important to note that if you restrict access to "/" then C<end>,
2143 C<default>, etc will also be restricted.
2145 MyApp->acl_allow_root_internals;
2147 will create rules that permit access to C<end>, C<begin>, and C<auto> in the
2148 root of your app (but not in any other controller).
2150 =head3 More Information
2152 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::Roles>
2153 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::ACL>
2157 Sebastian Riedel, C<sri@oook.de>
2158 Danijel Milicevic, C<me@danijel.de>
2159 Viljo Marrandi, C<vilts@yahoo.com>
2160 Marcus Ramberg, C<mramberg@cpan.org>
2161 Jesse Sheidlower, C<jester@panix.com>
2162 Andy Grundman, C<andy@hybridized.org>
2163 Chisel Wright, C<pause@herlpacker.co.uk>
2164 Will Hawes, C<info@whawes.co.uk>
2165 Gavin Henry, C<ghenry@perl.me.uk>
2170 This program is free software, you can redistribute it and/or modify it
2171 under the same terms as Perl itself.