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<Catlyst::Plugin::DefaultEnd>.
36 =head2 Disable statistics
38 Just add this line to your application class if you don't want those nifty
39 statistics in your debug messages.
41 sub Catalyst::Log::info { }
43 =head2 Enable debug status in the environment
45 Normally you enable the debugging info by adding the C<-Debug> flag to
46 your C<use Catalyst> statement. However, you can also enable it using
47 environment variable, so you can (for example) get debug info without
48 modifying your application scripts. Just set C<CATALYST_DEBUG> or
49 C<E<LT>MYAPPE<GT>_DEBUG> to a true value.
53 =head3 Single file upload with Catalyst
55 To implement uploads in Catalyst, you need to have a HTML form similar to
58 <form action="/upload" method="post" enctype="multipart/form-data">
59 <input type="hidden" name="form_submit" value="yes">
60 <input type="file" name="my_file">
61 <input type="submit" value="Send">
64 It's very important not to forget C<enctype="multipart/form-data"> in
67 Catalyst Controller module 'upload' action:
72 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
74 if ( my $upload = $c->request->upload('my_file') ) {
76 my $filename = $upload->filename;
77 my $target = "/tmp/upload/$filename";
79 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
80 die( "Failed to copy '$filename' to '$target': $!" );
85 $c->stash->{template} = 'file_upload.html';
88 =head3 Multiple file upload with Catalyst
90 Code for uploading multiple files from one form needs a few changes:
92 The form should have this basic structure:
94 <form action="/upload" method="post" enctype="multipart/form-data">
95 <input type="hidden" name="form_submit" value="yes">
96 <input type="file" name="file1" size="50"><br>
97 <input type="file" name="file2" size="50"><br>
98 <input type="file" name="file3" size="50"><br>
99 <input type="submit" value="Send">
102 And in the controller:
107 if ( $c->request->parameters->{form_submit} eq 'yes' ) {
109 for my $field ( $c->req->upload ) {
111 my $upload = $c->req->upload($field);
112 my $filename = $upload->filename;
113 my $target = "/tmp/upload/$filename";
115 unless ( $upload->link_to($target) || $upload->copy_to($target) ) {
116 die( "Failed to copy '$filename' to '$target': $!" );
121 $c->stash->{template} = 'file_upload.html';
124 C<for my $field ($c-E<gt>req->upload)> loops automatically over all file
125 input fields and gets input names. After that is basic file saving code,
126 just like in single file upload.
128 Notice: C<die>ing might not be what you want to do, when an error
129 occurs, but it works as an example. A better idea would be to store
130 error C<$!> in $c->stash->{error} and show a custom error template
131 displaying this message.
133 For more information about uploads and usable methods look at
134 L<Catalyst::Request::Upload> and L<Catalyst::Request>.
136 =head2 Authentication (logging in)
138 This is extensively covered in other documentation; see in particular
139 L<Catalyst::Plugin::Authentication> and the Authentication chapter
140 of the Tutorial at L<Catalyst::Manual::Tutorial::Authorization>.
142 =head2 Pass-through login (and other actions)
144 An easy way of having assorted actions that occur during the processing
145 of a request that are orthogonal to its actual purpose - logins, silent
146 commands etc. Provide actions for these, but when they're required for
147 something else fill e.g. a form variable __login and have a sub begin
150 sub begin : Private {
152 foreach my $action (qw/login docommand foo bar whatever/) {
153 if ($c->req->params->{"__${action}"}) {
154 $c->forward($action);
160 =head2 Serving static content
162 Serving static content in Catalyst used to be somewhat tricky; the use
163 of L<Catalyst::Plugin::Static::Simple> makes everything much easier.
164 This plugin will automatically serve your static content during development,
165 but allows you to easily switch to Apache (or other server) in a
166 production environment.
168 =head3 Introduction to Static::Simple
170 Static::Simple is a plugin that will help to serve static content for your
171 application. By default, it will serve most types of files, excluding some
172 standard Template Toolkit extensions, out of your B<root> file directory. All
173 files are served by path, so if B<images/me.jpg> is requested, then
174 B<root/images/me.jpg> is found and served.
178 Using the plugin is as simple as setting your use line in MyApp.pm to include:
180 use Catalyst qw/Static::Simple/;
182 and already files will be served.
186 Static content is best served from a single directory within your root
187 directory. Having many different directories such as C<root/css> and
188 C<root/images> requires more code to manage, because you must separately
189 identify each static directory--if you decide to add a C<root/js>
190 directory, you'll need to change your code to account for it. In
191 contrast, keeping all static directories as subdirectories of a main
192 C<root/static> directory makes things much easier to manage. Here's an
193 example of a typical root directory structure:
197 root/controller/stuff.tt
200 root/static/css/main.css
201 root/static/images/logo.jpg
202 root/static/js/code.js
205 All static content lives under C<root/static>, with everything else being
206 Template Toolkit files.
212 You may of course want to change the default locations, and make
213 Static::Simple look somewhere else, this is as easy as:
215 MyApp->config->{static}->{include_path} = [
216 MyApp->config->{root},
220 When you override include_path, it will not automatically append the
221 normal root path, so you need to add it yourself if you still want
222 it. These will be searched in order given, and the first matching file
225 =item Static directories
227 If you want to force some directories to be only static, you can set
228 them using paths relative to the root dir, or regular expressions:
230 MyApp->config->{static}->{dirs} = [
235 =item File extensions
237 By default, the following extensions are not served (that is, they will
238 be processed by Catalyst): B<tmpl, tt, tt2, html, xhtml>. This list can
241 MyApp->config->{static}->{ignore_extensions} = [
242 qw/tmpl tt tt2 html xhtml/
245 =item Ignoring directories
247 Entire directories can be ignored. If used with include_path,
248 directories relative to the include_path dirs will also be ignored:
250 MyApp->config->{static}->{ignore_dirs} = [ qw/tmpl css/ ];
254 =head3 More information
256 L<http://search.cpan.org/dist/Catalyst-Plugin-Static-Simple/>
258 =head3 Serving manually with the Static plugin with HTTP::Daemon (myapp_server.pl)
260 In some situations you might want to control things more directly,
261 using L<Catalyst::Plugin::Static>.
263 In your main application class (MyApp.pm), load the plugin:
265 use Catalyst qw/-Debug FormValidator Static OtherPlugin/;
267 You will also need to make sure your end method does I<not> forward
268 static content to the view, perhaps like this:
271 my ( $self, $c ) = @_;
273 $c->forward( 'MyApp::View::TT' )
274 unless ( $c->res->body || !$c->stash->{template} );
277 This code will only forward to the view if a template has been
278 previously defined by a controller and if there is not already data in
279 C<$c-E<gt>res-E<gt>body>.
281 Next, create a controller to handle requests for the /static path. Use
282 the Helper to save time. This command will create a stub controller as
283 C<lib/MyApp/Controller/Static.pm>.
285 $ script/myapp_create.pl controller Static
287 Edit the file and add the following methods:
289 # serve all files under /static as static files
290 sub default : Path('/static') {
291 my ( $self, $c ) = @_;
293 # Optional, allow the browser to cache the content
294 $c->res->headers->header( 'Cache-Control' => 'max-age=86400' );
296 $c->serve_static; # from Catalyst::Plugin::Static
299 # also handle requests for /favicon.ico
300 sub favicon : Path('/favicon.ico') {
301 my ( $self, $c ) = @_;
306 You can also define a different icon for the browser to use instead of
307 favicon.ico by using this in your HTML header:
309 <link rel="icon" href="/static/myapp.ico" type="image/x-icon" />
311 =head3 Common problems with the Static plugin
313 The Static plugin makes use of the C<shared-mime-info> package to
314 automatically determine MIME types. This package is notoriously
315 difficult to install, especially on win32 and OS X. For OS X the easiest
316 path might be to install Fink, then use C<apt-get install
317 shared-mime-info>. Restart the server, and everything should be fine.
319 Make sure you are using the latest version (>= 0.16) for best
320 results. If you are having errors serving CSS files, or if they get
321 served as text/plain instead of text/css, you may have an outdated
322 shared-mime-info version. You may also wish to simply use the following
323 code in your Static controller:
325 if ($c->req->path =~ /css$/i) {
326 $c->serve_static( "text/css" );
331 =head3 Serving Static Files with Apache
333 When using Apache, you can bypass Catalyst and any Static
334 plugins/controllers controller by intercepting requests for the
335 C<root/static> path at the server level. All that is required is to
336 define a DocumentRoot and add a separate Location block for your static
337 content. Here is a complete config for this application under mod_perl
341 use lib qw(/var/www/MyApp/lib);
346 ServerName myapp.example.com
347 DocumentRoot /var/www/MyApp/root
349 SetHandler perl-script
352 <LocationMatch "/(static|favicon.ico)">
353 SetHandler default-handler
357 And here's a simpler example that'll get you started:
359 Alias /static/ "/my/static/files/"
364 =head2 Forwarding with arguments
366 Sometimes you want to pass along arguments when forwarding to another
367 action. As of version 5.30, arguments can be passed in the call to
368 C<forward>; in earlier versions, you can manually set the arguments in
369 the Catalyst Request object:
371 # version 5.30 and later:
372 $c->forward('/wherever', [qw/arg1 arg2 arg3/]);
375 $c->req->args([qw/arg1 arg2 arg3/]);
376 $c->forward('/wherever');
378 (See the L<Catalyst::Manual::Intro> Flow_Control section for more
379 information on passing arguments via C<forward>.)
381 =head2 Configure your application
383 You configure your application with the C<config> method in your
384 application class. This can be hard-coded, or brought in from a
385 separate configuration file.
389 YAML is a method for creating flexible and readable configuration
390 files. It's a great way to keep your Catalyst application configuration
391 in one easy-to-understand location.
393 In your application class (e.g. C<lib/MyApp.pm>):
397 __PACKAGE__->config( YAML::LoadFile(__PACKAGE__->config->{'home'} . '/myapp.yml') );
400 Now create C<myapp.yml> in your application home:
403 # DO NOT USE TABS FOR INDENTATION OR label/value SEPARATION!!!
406 # session; perldoc Catalyst::Plugin::Session::FastMmap
410 storage: '/tmp/myapp.session'
412 # emails; perldoc Catalyst::Plugin::Email
413 # this passes options as an array :(
418 This is equivalent to:
420 # configure base package
421 __PACKAGE__->config( name => MyApp );
422 # configure authentication
423 __PACKAGE__->config->{authentication} = {
424 user_class => 'MyApp::Model::MyDB::Customer',
428 __PACKAGE__->config->{session} = {
432 # configure email sending
433 __PACKAGE__->config->{email} = [qw/SMTP localhost/];
437 =head2 Using existing DBIC (etc.) classes with Catalyst
439 Many people have existing Model classes that they would like to use with
440 Catalyst (or, conversely, they want to write Catalyst models that can be
441 used outside of Catalyst, e.g. in a cron job). It's trivial to write a
442 simple component in Catalyst that slurps in an outside Model:
444 package MyApp::Model::DB;
445 use base qw/Catalyst::Model::DBIC::Schema/;
447 schema_class => 'Some::DBIC::Schema',
448 connect_info => ['dbi:SQLite:foo.db', '', '', {AutoCommit=>1}];
452 and that's it! Now C<Some::DBIC::Schema> is part of your
453 Cat app as C<MyApp::Model::DB>.
455 =head2 Delivering a Custom Error Page
457 By default, Catalyst will display its own error page whenever it
458 encounters an error in your application. When running under C<-Debug>
459 mode, the error page is a useful screen including the error message and
460 L<Data::Dump> output of the relevant parts of the C<$c> context object.
461 When not in C<-Debug>, users see a simple "Please come back later" screen.
463 To use a custom error page, use a special C<end> method to short-circuit
464 the error processing. The following is an example; you might want to
465 adjust it further depending on the needs of your application (for
466 example, any calls to C<fillform> will probably need to go into this
467 C<end> method; see L<Catalyst::Plugin::FillInForm>).
470 my ( $self, $c ) = @_;
472 if ( scalar @{ $c->error } ) {
473 $c->stash->{errors} = $c->error;
474 $c->stash->{template} = 'errors.tt';
475 $c->forward('MyApp::View::TT');
479 return 1 if $c->response->status =~ /^3\d\d$/;
480 return 1 if $c->response->body;
482 unless ( $c->response->content_type ) {
483 $c->response->content_type('text/html; charset=utf-8');
486 $c->forward('MyApp::View::TT');
489 You can manually set errors in your code to trigger this page by calling
491 $c->error( 'You broke me!' );
493 =head2 Role-based Authorization
495 For more advanced access control, you may want to consider using role-based
496 authorization. This means you can assign different roles to each user, e.g.
497 "user", "admin", etc.
499 The C<login> and C<logout> methods and view template are exactly the same as
500 in the previous example.
502 The L<Catalyst::Plugin::Authorization::Roles> plugin is required when
507 Authentication::Credential::Password
508 Authentication::Store::Htpasswd
512 Roles are implemented automatically when using
513 L<Catalyst::Authentication::Store::Htpasswd>:
515 # no additional role configuration required
516 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
518 Or can be set up manually when using L<Catalyst::Authentication::Store::DBIC>:
520 # Authorization using a many-to-many role relationship
521 __PACKAGE__->config->{authorization}{dbic} = {
522 'role_class' => 'My::Model::DBIC::Role',
523 'role_field' => 'name',
524 'user_role_user_field' => 'user',
526 # DBIx::Class only (omit if using Class::DBI)
527 'role_rel' => 'user_role',
529 # Class::DBI only, (omit if using DBIx::Class)
530 'user_role_class' => 'My::Model::CDBI::UserRole'
531 'user_role_role_field' => 'role',
534 To restrict access to any action, you can use the C<check_user_roles> method:
536 sub restricted : Local {
537 my ( $self, $c ) = @_;
539 $c->detach("unauthorized")
540 unless $c->check_user_roles( "admin" );
542 # do something restricted here
545 You can also use the C<assert_user_roles> method. This just gives an error if
546 the current user does not have one of the required roles:
548 sub also_restricted : Global {
549 my ( $self, $c ) = @_;
550 $c->assert_user_roles( qw/ user admin / );
553 =head2 Quick deployment: Building PAR Packages
555 You have an application running on your development box, but then you
556 have to quickly move it to another one for
557 demonstration/deployment/testing...
559 PAR packages can save you from a lot of trouble here. They are usual Zip
560 files that contain a blib tree; you can even include all prereqs and a
561 perl interpreter by setting a few flags!
563 =head3 Follow these few points to try it out!
565 1. Install Catalyst and PAR 0.89 (or later)
567 % perl -MCPAN -e 'install Catalyst'
569 % perl -MCPAN -e 'install PAR'
572 2. Create a application
578 3. Add these lines to Makefile.PL (below "catalyst_files();")
580 catalyst_par_core(); # Include modules that are also included
581 # in the standard Perl distribution,
582 # this is optional but highly suggested
584 catalyst_par(); # Generate a PAR as soon as the blib
587 4. Prepare the Makefile, test your app, create a PAR (the two
588 Makefile.PL calls are no typo)
597 Recent versions of Catalyst include L<Module::Install::Catalyst>, which
598 simplifies the process greatly.
605 Congratulations! Your package "myapp.par" is ready, the following
606 steps are just optional.
608 5. Test your PAR package with "parl" (no typo)
612 [parl] myapp[.par] [script] [arguments]
615 parl myapp.par myapp_server.pl -r
625 % parl myapp.par myapp_server.pl
626 You can connect to your server at http://localhost:3000
628 Yes, this nifty little starter application gets automatically included.
629 You can also use "catalyst_par_script('myapp_server.pl')" to set a
630 default script to execute.
632 6. Want to create a binary that includes the Perl interpreter?
634 % pp -o myapp myapp.par
635 % ./myapp myapp_server.pl
636 You can connect to your server at http://localhost:3000
638 =head2 mod_perl Deployment
640 In today's entry, I'll be talking about deploying an application in
641 production using Apache and mod_perl.
645 mod_perl is the best solution for many applications, but I'll list some pros
646 and cons so you can decide for yourself. The other production deployment
647 option is FastCGI, which I'll talk about in a future calendar article.
653 mod_perl is very fast and your app will benefit from being loaded in memory
654 within each Apache process.
656 =head4 Shared memory for multiple apps
658 If you need to run several Catalyst apps on the same server, mod_perl will
659 share the memory for common modules.
665 Since your application is fully loaded in memory, every Apache process will
666 be rather large. This means a large Apache process will be tied up while
667 serving static files, large files, or dealing with slow clients. For this
668 reason, it is best to run a two-tiered web architecture with a lightweight
669 frontend server passing dynamic requests to a large backend mod_perl
674 Any changes made to the core code of your app require a full Apache restart.
675 Catalyst does not support Apache::Reload or StatINC. This is another good
676 reason to run a frontend web server where you can set up an
677 C<ErrorDocument 502> page to report that your app is down for maintenance.
679 =head4 Cannot run multiple versions of the same app
681 It is not possible to run two different versions of the same application in
682 the same Apache instance because the namespaces will collide.
686 Now that we have that out of the way, let's talk about setting up mod_perl
687 to run a Catalyst app.
689 =head4 1. Install Catalyst::Engine::Apache
691 You should install the latest versions of both Catalyst and
692 Catalyst::Engine::Apache. The Apache engines were separated from the
693 Catalyst core in version 5.50 to allow for updates to the engine without
694 requiring a new Catalyst release.
696 =head4 2. Install Apache with mod_perl
698 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
699 recommended. With Apache 2, make sure you are using the prefork MPM and not
700 the worker MPM. The reason for this is that many Perl modules are not
701 thread-safe and may have problems running within the threaded worker
702 environment. Catalyst is thread-safe however, so if you know what you're
703 doing, you may be able to run using worker.
705 In Debian, the following commands should get you going.
707 apt-get install apache2-mpm-prefork
708 apt-get install libapache2-mod-perl2
710 =head4 3. Configure your application
712 Every Catalyst application will automagically become a mod_perl handler
713 when run within mod_perl. This makes the configuration extremely easy.
714 Here is a basic Apache 2 configuration.
716 PerlSwitches -I/var/www/MyApp/lib
721 PerlResponseHandler MyApp
724 The most important line here is C<PerlModule MyApp>. This causes mod_perl
725 to preload your entire application into shared memory, including all of your
726 controller, model, and view classes and configuration. If you have -Debug
727 mode enabled, you will see the startup output scroll by when you first
730 For an example Apache 1.3 configuration, please see the documentation for
731 L<Catalyst::Engine::Apache::MP13>.
735 That's it, your app is now a full-fledged mod_perl application! Try it out
736 by going to http://your.server.com/.
740 =head4 Non-root location
742 You may not always want to run your app at the root of your server or virtual
743 host. In this case, it's a simple change to run at any non-root location
748 PerlResponseHandler MyApp
751 When running this way, it is best to make use of the C<uri_for> method in
752 Catalyst for constructing correct links.
754 =head4 Static file handling
756 Static files can be served directly by Apache for a performance boost.
758 DocumentRoot /var/www/MyApp/root
760 SetHandler default-handler
763 This will let all files within root/static be handled directly by Apache. In
764 a two-tiered setup, the frontend server should handle static files.
765 The configuration to do this on the frontend will vary.
767 =head2 Extending DefaultEnd
769 Most people use L<Catalyst::Plugin::DefaultEnd> as their
770 end action; it does what you usually need. However there are
771 times when you need to add a bit to it, but don't want to
772 write your own C<end> action.
774 Simply extend it like this:
776 use Catalyst qw/DefaultEnd/;
781 my ( $self, $c ) = @_;
783 ... # code before view
787 ... # code after view
790 =head2 Catalyst on shared hosting
792 So, you want to put your Catalyst app out there for the whole world to
793 see, but you don't want to break the bank. There is an answer - if you
794 can get shared hosting with FastCGI and a shell, you can install your
795 Catalyst app in a local directory on your shared host. First, run
799 and go through the standard CPAN configuration process. Then exit out
800 without installing anything. Next, open your .bashrc and add
802 export PATH=$HOME/local/bin:$HOME/local/script:$PATH
803 perlversion=`perl -v | grep 'built for' | awk '{print $4}' | sed -e 's/v//;'`
804 export PERL5LIB=$HOME/local/share/perl/$perlversion:$HOME/local/lib/perl/$perlversion:$HOME/local/lib:$PERL5LIB
806 and log out, then back in again (or run C<". .bashrc"> if you
807 prefer). Finally, edit C<.cpan/CPAN/MyConfig.pm> and add
809 'make_install_arg' => qq[SITEPREFIX=$ENV{HOME}/local],
810 'makepl_arg' => qq[INSTALLDIRS=site install_base=$ENV{HOME}/local],
812 Now you can install the modules you need using CPAN as normal; they
813 will be installed into your local directory, and perl will pick them
814 up. Finally, change directory into the root of your virtual host and
815 symlink your application's script directory in:
817 cd path/to/mydomain.com
818 ln -s ~/lib/MyApp/script script
820 And add the following lines to your .htaccess file (assuming the server
821 is setup to handle .pl as fcgi - you may need to rename the script to
822 myapp_fastcgi.fcgi and/or use a SetHandler directive):
825 RewriteCond %{REQUEST_URI} !^/?script/myapp_fastcgi.pl
826 RewriteRule ^(.*)$ script/myapp_fastcgi.pl/$1 [PT,L]
828 Now C<http://mydomain.com/> should now Just Work. Congratulations, now
829 you can tell your friends about your new website (or in our case, tell
830 the client it's time to pay the invoice :) )
834 Catalyst makes it easy to employ several different types of caching to
835 speed up your applications.
839 There are three wrapper plugins around common CPAN cache modules:
840 Cache::FastMmap, Cache::FileCache, and Cache::Memcached. These can be
841 used to cache the result of slow operations.
843 This very page you're viewing makes use of the FileCache plugin to cache the
844 rendered XHTML version of the source POD document. This is an ideal
845 application for a cache because the source document changes infrequently but
846 may be viewed many times.
848 use Catalyst qw/Cache::FileCache/;
853 sub render_pod : Local {
854 my ( self, $c ) = @_;
856 # the cache is keyed on the filename and the modification time
857 # to check for updates to the file.
858 my $file = $c->path_to( 'root', '2005', '11.pod' );
859 my $mtime = ( stat $file )->mtime;
861 my $cached_pod = $c->cache->get("$file $mtime");
862 if ( !$cached_pod ) {
863 $cached_pod = do_slow_pod_rendering();
864 # cache the result for 12 hours
865 $c->cache->set( "$file $mtime", $cached_pod, '12h' );
867 $c->stash->{pod} = $cached_pod;
870 We could actually cache the result forever, but using a value such as 12 hours
871 allows old entries to be automatically expired when they are no longer needed.
875 Another method of caching is to cache the entire HTML page. While this is
876 traditionally handled by a front-end proxy server like Squid, the Catalyst
877 PageCache plugin makes it trivial to cache the entire output from
878 frequently-used or slow actions.
880 Many sites have a busy content-filled front page that might look something
881 like this. It probably takes a while to process, and will do the exact same
882 thing for every single user who views the page.
884 sub front_page : Path('/') {
885 my ( $self, $c ) = @_;
887 $c->forward( 'get_news_articles' );
888 $c->forward( 'build_lots_of_boxes' );
889 $c->forward( 'more_slow_stuff' );
891 $c->stash->{template} = 'index.tt';
894 We can add the PageCache plugin to speed things up.
896 use Catalyst qw/Cache::FileCache PageCache/;
898 sub front_page : Path ('/') {
899 my ( $self, $c ) = @_;
901 $c->cache_page( 300 );
903 # same processing as above
906 Now the entire output of the front page, from <html> to </html>, will be
907 cached for 5 minutes. After 5 minutes, the next request will rebuild the
908 page and it will be re-cached.
910 Note that the page cache is keyed on the page URI plus all parameters, so
911 requests for / and /?foo=bar will result in different cache items. Also,
912 only GET requests will be cached by the plugin.
914 You can even get that front-end Squid proxy to help out by enabling HTTP
915 headers for the cached page.
917 MyApp->config->{page_cache}->{set_http_headers} = 1;
919 This would now set the following headers so proxies and browsers may cache
920 the content themselves.
922 Cache-Control: max-age=($expire_time - time)
923 Expires: $expire_time
924 Last-Modified: $cache_created_time
926 =head3 Template Caching
928 Template Toolkit provides support for caching compiled versions of your
929 templates. To enable this in Catalyst, use the following configuration.
930 TT will cache compiled templates keyed on the file mtime, so changes will
931 still be automatically detected.
933 package MyApp::View::TT;
937 use base 'Catalyst::View::TT';
940 COMPILE_DIR => '/tmp/template_cache',
947 See the documentation for each cache plugin for more details and other
948 available configuration options.
950 L<Catalyst::Plugin::Cache::FastMmap>
951 L<Catalyst::Plugin::Cache::FileCache>
952 L<Catalyst::Plugin::Cache::Memcached>
953 L<Catalyst::Plugin::PageCache>
954 L<http://search.cpan.org/dist/Template-Toolkit/lib/Template/Manual/Config.pod#Caching_and_Compiling_Options>
956 =head2 Component-based Subrequests
958 See L<Catalyst::Plugin::SubRequest>.
960 =head2 DBIx::Class as a Catalyst Model
962 See L<Catalyst::Model::DBIC::Schema>.
964 =head2 Authentication/Authorization
966 This is done in several steps:
972 Getting the user to identify themselves, by giving you some piece of
973 information known only to you and the user. Then you can assume that the user
974 is who they say they are. This is called B<credential verification>.
978 Making sure the user only accesses functions you want them to access. This is
979 done by checking the verified users data against your internal list of groups,
980 or allowed persons for the current page.
986 The Catalyst Authentication system is made up of many interacting modules, to
987 give you the most flexibility possible.
989 =head4 Credential verifiers
991 A Credential module tables the user input, and passes it to a Store, or some
992 other system, for verification. Typically, a user object is created by either
993 this module or the Store and made accessible by a C<< $c->user >> call.
997 Password - Simple username/password checking.
998 HTTPD - Checks using basic HTTP auth.
999 TypeKey - Check using the typekey system.
1001 =head3 Storage backends
1003 A Storage backend contains the actual data representing the users. It is
1004 queried by the credential verifiers. Updating the store is not done within
1005 this system, you will need to do it yourself.
1009 DBIC - Storage using a database.
1010 Minimal - Storage using a simple hash (for testing).
1014 A User object is created by either the storage backend or the credential
1015 verifier, and filled with the retrieved user information.
1019 Hash - A simple hash of keys and values.
1021 =head3 ACL authorization
1023 ACL stands for Access Control List. The ACL plugin allows you to regulate
1024 access on a path by path basis, by listing which users, or roles, have access
1027 =head3 Roles authorization
1029 Authorization by roles is for assigning users to groups, which can then be
1030 assigned to ACLs, or just checked when needed.
1034 When you have chosen your modules, all you need to do is call the C<<
1035 $c->login >> method. If called with no parameters, it will try to find
1036 suitable parameters, such as B<username> and B<password>, or you can pass it
1039 =head3 Checking roles
1041 Role checking is done by using the C<< $c->check_user_roles >> method, this will
1042 check using the currently logged in user (via C<< $c->user >>). You pass it
1043 the name of a role to check, and it returns true if the user is a member.
1047 use Catalyst qw/Authentication
1048 Authentication::Credential::Password
1049 Authentication::Store::Htpasswd
1050 Authorization::Roles/;
1052 __PACKAGE__->config->{authentication}{htpasswd} = "passwdfile";
1055 my ($self, $c) = @_;
1057 if ( my $user = $c->req->param("user")
1058 and my $password = $c->req->param("password") )
1060 if ( $c->login( $user, $password ) ) {
1061 $c->res->body( "hello " . $c->user->name );
1067 # invalid form input
1071 sub restricted : Local {
1072 my ( $self, $c ) = @_;
1074 $c->detach("unauthorized")
1075 unless $c->check_user_roles( "admin" );
1077 # do something restricted here
1080 =head3 Using authentication in a testing environment
1082 Ideally, to write tests for authentication/authorization code one would first
1083 set up a test database with known data, then use
1084 L<Test::WWW::Mechanize::Catalyst> to simulate a user logging in. Unfortunately
1085 the former can be rather awkward, which is why it's a good thing that the
1086 authentication framework is so flexible.
1088 Instead of using a test database, one can simply change the authentication
1089 store to something a bit easier to deal with in a testing
1090 environment. Additionally, this has the advantage of not modifying one's
1091 database, which can be problematic if one forgets to use the testing instead of
1092 production database.
1096 use Catalyst::Plugin::Authentication::Store::Minimal::Backend;
1098 # Sets up the user `test_user' with password `test_pass'
1099 MyApp->default_auth_store(
1100 Catalyst::Plugin::Authentication::Store::Minimal::Backend->new({
1101 test_user => { password => 'test_pass' },
1105 Now, your test code can call C<$c->login('test_user', 'test_pass')> and
1106 successfully login, without messing with the database at all.
1108 =head3 More information
1110 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authentication> has a longer explanation.
1114 When you have your users identified, you will want to somehow remember that
1115 fact, to save them from having to identify themselves for every single
1116 page. One way to do this is to send the username and password parameters in
1117 every single page, but that's ugly, and won't work for static pages.
1119 Sessions are a method of saving data related to some transaction, and giving
1120 the whole collection a single ID. This ID is then given to the user to return
1121 to us on every page they visit while logged in. The usual way to do this is
1122 using a browser cookie.
1124 Catalyst uses two types of plugins to represent sessions:
1128 A State module is used to keep track of the state of the session between the
1129 users browser, and your application.
1131 A common example is the Cookie state module, which sends the browser a cookie
1132 containing the session ID. It will use default value for the cookie name and
1133 domain, so will "just work" when used.
1137 A Store module is used to hold all the data relating to your session, for
1138 example the users ID, or the items for their shopping cart. You can store data
1139 in memory (FastMmap), in a file (File) or in a database (DBI).
1141 =head3 Authentication magic
1143 If you have included the session modules in your application, the
1144 Authentication modules will automagically use your session to save and
1145 retrieve the user data for you.
1147 =head3 Using a session
1149 Once the session modules are loaded, the session is available as C<<
1150 $c->session >>, and can be writen to and read from as a simple hash reference.
1156 Session::Store::FastMmap
1157 Session::State::Cookie
1161 ## Write data into the session
1163 sub add_item : Local {
1164 my ( $self, $c ) = @_;
1166 my $item_id = $c->req->param("item");
1168 push @{ $c->session->{items} }, $item_id;
1172 ## A page later we retrieve the data from the session:
1174 sub get_items : Local {
1175 my ( $self, $c ) = @_;
1177 $c->stash->{items_to_display} = $c->session->{items};
1182 =head3 More information
1184 L<http://search.cpan.org/dist/Catalyst-Plugin-Session>
1186 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-Cookie>
1188 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-State-URI>
1190 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-FastMmap>
1192 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-File>
1194 L<http://search.cpan.org/dist/Catalyst-Plugin-Session-Store-DBI>
1196 =head2 Adding RSS feeds
1198 Adding RSS feeds to your stuff in Catalyst is really simple. I'll show two
1199 different aproaches here, but the basic premise is that you forward to the
1200 normal view action first to get the objects, then handle the output differently
1202 =head3 Using TT templates
1204 This is the aproach we chose in Agave (L<http://dev.rawmode.org/>).
1208 $c->forward('view');
1209 $c->stash->{template}='rss.tt';
1212 Then you need a template. Here's the one from Agave:
1213 L<http://svn.rawmode.org/repos/Agave/trunk/root/base/blog/rss.tt>
1215 As you can see, it's pretty simple.
1217 =head3 Using XML::Feed
1219 However, a more robust solution is to use XML::Feed, as we've done in this
1220 Advent Calendar. Assuming we have a 'view' action that populates 'entries'
1221 with some DBIx::Class/Class::DBI iterator, the code would look something like
1226 $c->forward('view'); # get the entries
1228 my $feed = XML::Feed->new('RSS');
1229 $feed->title( $c->config->{name} . ' RSS Feed' );
1230 $feed->link( $c->req->base ); # link to the site.
1231 $feed->description('Catalyst advent calendar'); Some description
1233 # Process the entries
1234 while( my $entry=$c->stash->{entries}->next ) {
1235 my $feed_entry = XML::Feed::Entry->new('RSS');
1236 $feed_entry->title($entry->title);
1237 $feed_entry->link( $c->uri_for($entry->link) );
1238 $feed_entry->issued( DateTime->from_epoch(epoch => $entry->created) );
1239 $feed->add_entry($feed_entry);
1241 $c->res->body( $feed->as_xml );
1245 A little more code in the controller, but with this approach you're pretty sure
1246 to get something that validates. One little note regarding that tho, for both
1247 of the above aproaches, you'll need to set the content type like this:
1249 $c->res->content_type('application/rss+xml');
1253 Note that you could generalize the second variant easily by replacing 'RSS'
1254 with a variable, so you can generate Atom feeds with the same code.
1256 Now, go ahead and make RSS feeds for all your stuff. The world *needs* updates
1259 =head2 FastCGI Deployment
1261 As a companion to Day 7's mod_perl article, today's article is about
1262 production FastCGI deployment.
1268 FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you;
1269 your app runs as multiple persistent processes ready to receive connections
1270 from the web server.
1274 When using external FastCGI servers, your application runs as a standalone
1275 application server. It may be restarted independently from the web server.
1276 This allows for a more robust environment and faster reload times when
1277 pushing new app changes. The frontend server can even be configured to
1278 display a friendly "down for maintenance" page while the application is
1281 =head4 Load-balancing
1283 You can launch your application on multiple backend servers and allow the
1284 frontend web server to load-balance between all of them. And of course, if
1285 one goes down, your app continues to run fine.
1287 =head4 Multiple versions of the same app
1289 Each FastCGI application is a separate process, so you can run different
1290 versions of the same app on a single server.
1292 =head4 Can run with threaded Apache
1294 Since your app is not running inside of Apache, the faster mpm_worker module
1295 can be used without worrying about the thread safety of your application.
1299 =head4 More complex environment
1301 With FastCGI, there are more things to monitor and more processes running
1302 than when using mod_perl.
1306 =head4 1. Install Apache with mod_fastcgi
1308 mod_fastcgi for Apache is a third party module, and can be found at
1309 L<http://www.fastcgi.com/>. It is also packaged in many distributions, for
1310 example, libapache2-mod-fastcgi in Debian.
1312 =head4 2. Configure your application
1314 # Serve static content directly
1315 DocumentRoot /var/www/MyApp/root
1316 Alias /static /var/www/MyApp/root/static
1318 FastCgiServer /var/www/MyApp/script/myapp_fastcgi.pl -processes 3
1319 Alias /myapp/ /var/www/MyApp/script/myapp_fastcgi.pl/
1321 # Or, run at the root
1322 Alias / /var/www/MyApp/script/myapp_fastcgi.pl/
1324 The above commands will launch 3 app processes and make the app available at
1327 =head3 Standalone server mode
1329 While not as easy as the previous method, running your app as an external
1330 server gives you much more flexibility.
1332 First, launch your app as a standalone server listening on a socket.
1334 script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5 -p /tmp/myapp.pid -d
1336 You can also listen on a TCP port if your web server is not on the same
1339 script/myapp_fastcgi.pl -l :8080 -n 5 -p /tmp/myapp.pid -d
1341 You will probably want to write an init script to handle starting/stopping
1342 of the app using the pid file.
1344 Now, we simply configure Apache to connect to the running server.
1346 # 502 is a Bad Gateway error, and will occur if the backend server is down
1347 # This allows us to display a friendly static page that says "down for
1349 Alias /_errors /var/www/MyApp/root/error-pages
1350 ErrorDocument 502 /_errors/502.html
1352 FastCgiExternalServer /tmp/myapp -socket /tmp/myapp.socket
1353 Alias /myapp/ /tmp/myapp/
1355 # Or, run at the root
1360 Lots more information is available in the new and expanded FastCGI docs that
1361 will be part of Catalyst 5.62. For now you may read them here:
1362 L<http://dev.catalyst.perl.org/file/trunk/Catalyst/lib/Catalyst/Engine/FastCGI.pm>
1364 =head2 Catalyst::View::TT
1366 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.
1368 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.
1370 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.
1372 =head3 Creating your View
1374 Catalyst::View::TT provides two different helpers for use to use: TT and TTSite.
1378 Create a basic Template Toolkit View using the provided helper script:
1380 script/myapp_create.pl view TT TT
1382 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:
1385 my ( $self, $c ) = @_;
1387 $c->stash->{template} = 'hello.tt';
1389 $c->forward( $c->view('TT') );
1392 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.
1396 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.
1398 Once again, you can use the helper script:
1400 script/myapp_create.pl view TT TTSite
1402 This time, the helper sets several options for us in the generated View.
1404 __PACKAGE__->config({
1405 CATALYST_VAR => 'Catalyst',
1407 MyApp->path_to( 'root', 'src' ),
1408 MyApp->path_to( 'root', 'lib' )
1410 PRE_PROCESS => 'config/main',
1411 WRAPPER => 'site/wrapper',
1412 ERROR => 'error.tt2',
1419 INCLUDE_PATH defines the directories that Template Toolkit should search for the template files.
1422 PRE_PROCESS is used to process configuration options which are common to every template file.
1425 WRAPPER is a file which is processed with each template, usually used to easily provide a common header and footer for every page.
1429 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.
1431 Several configuration files in root/lib/config are called by PRE_PROCESS.
1433 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.
1435 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.
1439 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.
1441 In our controllers, we can add data to the stash, and then access it from the template. For instance:
1444 my ( $self, $c ) = @_;
1446 $c->stash->{name} = 'Adam';
1448 $c->stash->{template} = 'hello.tt';
1450 $c->forward( $c->view('TT') );
1455 <strong>Hello, [% name %]!</strong>
1457 When you view this page, it will display "Hello, Adam!"
1459 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.
1464 my ( $self, $c ) = @_;
1466 $c->stash->{names} = [ 'Adam', 'Dave', 'John' ];
1468 $c->stash->{template} = 'hello.tt';
1470 $c->forward( $c->view('TT') );
1475 [% FOREACH name IN names %]
1476 <strong>Hello, [% name %]!</strong><br />
1479 This allowed us to loop through each item in the arrayref, and display a line for each name that we have.
1481 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.
1483 =head3 $c->uri_for()
1485 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.
1487 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.
1489 In your template, you can use the following:
1491 <a href="[% c.uri_for('/login') %]">Login Here</a>
1493 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.
1497 <a href="[% c.uri_for('2005','10', '24') %]">October, 24 2005</a>
1499 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.
1501 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.
1505 L<http://search.cpan.org/perldoc?Catalyst>
1507 L<http://search.cpan.org/perldoc?Catalyst%3A%3AView%3A%3ATT>
1509 L<http://search.cpan.org/perldoc?Template>
1513 Catalyst provides a convenient way of testing your application during
1514 development and before deployment in a real environment.
1516 C<Catalyst::Test> makes it possible to run the same tests both locally
1517 (without an external daemon) and against a remote server via HTTP.
1521 Let's examine a skeleton application's C<t/> directory:
1523 mundus:~/MyApp chansen$ ls -l t/
1525 -rw-r--r-- 1 chansen chansen 95 18 Dec 20:50 01app.t
1526 -rw-r--r-- 1 chansen chansen 190 18 Dec 20:50 02pod.t
1527 -rw-r--r-- 1 chansen chansen 213 18 Dec 20:50 03podcoverage.t
1533 Verifies that the application loads, compiles, and returns a successful
1538 Verifies that all POD is free from errors. Only executed if the C<TEST_POD>
1539 environment variable is true.
1541 =item C<03podcoverage.t>
1543 Verifies that all methods/functions have POD coverage. Only executed if the
1544 C<TEST_POD> environment variable is true.
1548 =head3 Creating tests
1550 mundus:~/MyApp chansen$ cat t/01app.t | perl -ne 'printf( "%2d %s", $., $_ )'
1551 1 use Test::More tests => 2;
1552 2 use_ok( Catalyst::Test, 'MyApp' );
1554 4 ok( request('/')->is_success );
1556 The first line declares how many tests we are going to run, in this case
1557 two. The second line tests and loads our application in test mode. The
1558 fourth line verifies that our application returns a successful response.
1560 C<Catalyst::Test> exports two functions, C<request> and C<get>. Each can
1561 take three different arguments:
1565 =item A string which is a relative or absolute URI.
1567 request('/my/path');
1568 request('http://www.host.com/my/path');
1570 =item An instance of C<URI>.
1572 request( URI->new('http://www.host.com/my/path') );
1574 =item An instance of C<HTTP::Request>.
1576 request( HTTP::Request->new( GET => 'http://www.host.com/my/path') );
1580 C<request> returns an instance of C<HTTP::Response> and C<get> returns the
1581 content (body) of the response.
1583 =head3 Running tests locally
1585 mundus:~/MyApp chansen$ CATALYST_DEBUG=0 TEST_POD=1 prove --lib lib/ t/
1586 t/01app............ok
1587 t/02pod............ok
1588 t/03podcoverage....ok
1589 All tests successful.
1590 Files=3, Tests=4, 2 wallclock secs ( 1.60 cusr + 0.36 csys = 1.96 CPU)
1592 C<CATALYST_DEBUG=0> ensures that debugging is off; if it's enabled you
1593 will see debug logs between tests.
1595 C<TEST_POD=1> enables POD checking and coverage.
1597 C<prove> A command-line tool that makes it easy to run tests. You can
1598 find out more about it from the links below.
1600 =head3 Running tests remotely
1602 mundus:~/MyApp chansen$ CATALYST_SERVER=http://localhost:3000/ prove --lib lib/ t/01app.t
1604 All tests successful.
1605 Files=1, Tests=2, 0 wallclock secs ( 0.40 cusr + 0.01 csys = 0.41 CPU)
1607 C<CATALYST_SERVER=http://localhost:3000/> is the absolute deployment URI of
1608 your application. In C<CGI> or C<FastCGI> it should be the host and path
1611 =head3 C<Test::WWW::Mechanize> and Catalyst
1613 Be sure to check out C<Test::WWW::Mechanize::Catalyst>. It makes it easy to
1614 test HTML, forms and links. A short example of usage:
1616 use Test::More tests => 6;
1617 use_ok( Test::WWW::Mechanize::Catalyst, 'MyApp' );
1619 my $mech = Test::WWW::Mechanize::Catalyst->new;
1620 $mech->get_ok("http://localhost/", 'Got index page');
1621 $mech->title_like( qr/^MyApp on Catalyst/, 'Got right index title' );
1622 ok( $mech->find_link( text_regex => qr/^Wiki/i ), 'Found link to Wiki' );
1623 ok( $mech->find_link( text_regex => qr/^Mailing-List/i ), 'Found link to Mailing-List' );
1624 ok( $mech->find_link( text_regex => qr/^IRC channel/i ), 'Found link to IRC channel' );
1626 =head3 Further Reading
1630 =item Catalyst::Test
1632 L<http://search.cpan.org/dist/Catalyst/lib/Catalyst/Test.pm>
1634 =item Test::WWW::Mechanize::Catalyst
1636 L<http://search.cpan.org/dist/Test-WWW-Mechanize-Catalyst/lib/Test/WWW/Mechanize/Catalyst.pm>
1638 =item Test::WWW::Mechanize
1640 L<http://search.cpan.org/dist/Test-WWW-Mechanize/Mechanize.pm>
1642 =item WWW::Mechanize
1644 L<http://search.cpan.org/dist/WWW-Mechanize/lib/WWW/Mechanize.pm>
1646 =item LWP::UserAgent
1648 L<http://search.cpan.org/dist/libwww-perl/lib/LWP/UserAgent.pm>
1652 L<http://search.cpan.org/dist/libwww-perl/lib/HTML/Form.pm>
1656 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Message.pm>
1660 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request.pm>
1662 =item HTTP::Request::Common
1664 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Request/Common.pm>
1666 =item HTTP::Response
1668 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Response.pm>
1672 L<http://search.cpan.org/dist/libwww-perl/lib/HTTP/Status.pm>
1676 L<http://search.cpan.org/dist/URI/URI.pm>
1680 L<http://search.cpan.org/dist/Test-Simple/lib/Test/More.pm>
1684 L<http://search.cpan.org/dist/Test-Pod/Pod.pm>
1686 =item Test::Pod::Coverage
1688 L<http://search.cpan.org/dist/Test-Pod-Coverage/Coverage.pm>
1690 =item prove (Test::Harness)
1692 L<http://search.cpan.org/dist/Test-Harness/bin/prove>
1698 Today we'll discover the wonderful world of web services.
1699 XMLRPC is unlike SOAP a very simple (and imo elegant) protocol,
1700 exchanging small XML messages like these.
1705 TE: deflate,gzip;q=0.3
1706 Connection: TE, close
1709 Host: 127.0.0.1:3000
1710 User-Agent: SOAP::Lite/Perl/0.60
1712 Content-Type: text/xml
1714 <?xml version="1.0" encoding="UTF-8"?>
1716 <methodName>add</methodName>
1718 <param><value><int>1</int></value></param>
1719 <param><value><int>2</int></value></param>
1726 Date: Tue, 20 Dec 2005 07:45:55 GMT
1728 Content-Type: text/xml
1732 <?xml version="1.0" encoding="us-ascii"?>
1735 <param><value><int>3</int></value></param>
1739 Sweet little protocol, isn't it? :)
1741 Now follow these few steps to implement the application.
1743 1. Install Catalyst (5.61 or later), Catalyst::Plugin::XMLRPC (0.06 or later) and SOAP::Lite (for XMLRPCsh.pl)
1745 % perl -MCPAN -e'install Catalyst'
1747 % perl -MCPAN -e'install Catalyst::Plugin::XMLRPC'
1756 3. Add the XMLRPC plugin to MyApp.pm
1758 use Catalyst qw/-Debug Static::Simple XMLRPC/;
1760 4. Add a api controller
1762 % ./script/myapp_create.pl controller API
1764 5. Add a XMLRPC redispatch method and a add method with Remote attribute
1765 to lib/MyApp/Controller/API.pm
1767 sub default : Private {
1768 my ( $self, $c ) = @_;
1773 my ( $self, $c, $a, $b ) = @_;
1777 The default action is the entry point for each XMLRPC request, it will
1778 redispatch every request to methods with Remote attribute in the same class.
1780 The add method is no traditional action, it has no private or public path.
1781 Only the XMLRPC dispatcher knows it exists.
1783 6. Thats it! You have built your first web service, lets test it with
1784 XMLRPCsh.pl (part of SOAP::Lite)
1786 % ./script/myapp_server.pl
1788 % XMLRPCsh.pl http://127.0.0.1:3000/api
1789 Usage: method[(parameters)]
1791 --- XMLRPC RESULT ---
1794 =head3 Tip Of The Day
1796 Your return data type is usually auto-detected, but you can easily
1797 enforce a specific one.
1800 my ( $self, $c, $a, $b ) = @_;
1801 return RPC::XML::int->new( $a + $b );
1808 A Catalyst application is driven by one or more Controller modules. There are
1809 a number of ways that Catalyst can decide which of the methods in your
1810 controller modules it should call. Controller methods are also called actions,
1811 because they determine how your catalyst application should (re-)act to any
1812 given URL. When the application is started up, catalyst looks at all your
1813 actions, and decides which URLs they map to.
1815 =head3 Type attributes
1817 Each action is a normal method in your controller, except that it has an
1818 L<attribute|http://search.cpan.org/~nwclark/perl-5.8.7/lib/attributes.pm>
1819 attached. These can be one of several types.
1821 Assume our Controller module starts with the following package declaration:
1823 package MyApp::Controller::Buckets;
1825 and we are running our application on localhost, port 3000 (the test server default).
1831 A Path attribute also takes an argument, this can be either a relative or an
1832 absolute path. A relative path will be relative to the controller namespace,
1833 an absolute path will represent an exact matching URL.
1835 sub my_handles : Path('handles') { .. }
1839 http://localhost:3000/buckets/handles
1843 sub my_handles : Path('/handles') { .. }
1847 http://localhost:3000/handles
1851 When using a Local attribute, no parameters are needed, instead, the name of
1852 the action is matched in the URL. The namespaces created by the name of the
1853 controller package is always part of the URL.
1855 sub my_handles : Local { .. }
1859 http://localhost:3000/buckets/my_handles
1863 A Global attribute is similar to a Local attribute, except that the namespace
1864 of the controller is ignored, and matching starts at root.
1866 sub my_handles : Global { .. }
1870 http://localhost:3000/my_handles
1874 By now you should have figured that a Regex attribute is just what it sounds
1875 like. This one takes a regular expression, and matches starting from
1876 root. These differ from the rest as they can match multiple URLs.
1878 sub my_handles : Regex('^handles') { .. }
1882 http://localhost:3000/handles
1886 http://localhost:3000/handles_and_other_parts
1892 A LocalRegex is similar to a Regex, except it only matches below the current
1893 controller namespace.
1895 sub my_handles : LocalRegex(^handles') { .. }
1899 http://localhost:3000/buckets/handles
1903 http://localhost:3000/buckets/handles_and_other_parts
1909 Last but not least, there is the Private attribute, which allows you to create
1910 your own internal actions, which can be forwarded to, but won't be matched as
1913 sub my_handles : Private { .. }
1915 becomes nothing at all..
1917 Catalyst also predefines some special Private actions, which you can override,
1924 The default action will be called, if no other matching action is found. If
1925 you don't have one of these in your namespace, or any sub part of your
1926 namespace, you'll get an error page instead. If you want to find out where it
1927 was the user was trying to go, you can look in the request object using
1928 C<< $c->req->path >>.
1930 sub default : Private { .. }
1932 works for all unknown URLs, in this controller namespace, or every one if put
1933 directly into MyApp.pm.
1937 The index action is called when someone tries to visit the exact namespace of
1938 your controller. If index, default and matching Path actions are defined, then
1939 index will be used instead of default and Path.
1941 sub index : Private { .. }
1945 http://localhost:3000/buckets
1949 The begin action is called at the beginning of every request involving this
1950 namespace directly, before other matching actions are called. It can be used
1951 to set up variables/data for this particular part of your app. A single begin
1952 action is called, its always the one most relevant to the current namespace.
1954 sub begin : Private { .. }
1958 http://localhost:3000/bucket/(anything)?
1964 Like begin, this action is always called for the namespace it is in, after
1965 every other action has finished. It is commonly used to forward processing to
1966 the View component. A single end action is called, its always the one most
1967 relevant to the current namespace.
1970 sub end : Private { .. }
1972 is called once after any actions when
1974 http://localhost:3000/bucket/(anything)?
1980 Lastly, the auto action is magic in that B<every> auto action in
1981 the chain of paths up to and including the ending namespace, will be
1982 called. (In contrast, only one of the begin/end/default actions will be
1983 called, the relevant one).
1986 sub auto : Private { .. }
1990 sub auto : Private { .. }
1992 will both be called when visiting
1994 http://localhost:3000/bucket/(anything)?
2000 =head3 A word of warning
2002 Due to possible namespace conflicts with Plugins, it is advised to only put the
2003 pre-defined Private actions in your main MyApp.pm file, all others should go
2004 in a Controller module.
2006 =head3 More Information
2008 L<http://search.cpan.org/author/SRI/Catalyst-5.61/lib/Catalyst/Manual/Intro.pod>
2010 L<http://dev.catalyst.perl.org/wiki/FlowChart>
2013 =head2 Authorization
2017 Authorization is the step that comes after authentication. Authentication
2018 establishes that the user agent is really representing the user we think it's
2019 representing, and then authorization determines what this user is allowed to
2022 =head3 Role Based Access Control
2024 Under role based access control each user is allowed to perform any number of
2025 roles. For example, at a zoo no one but specially trained personnel can enter
2026 the moose cage (Mynd you, møøse bites kan be pretty nasti!). For example:
2028 package Zoo::Controller::MooseCage;
2030 sub feed_moose : Local {
2031 my ( $self, $c ) = @_;
2033 $c->model( "Moose" )->eat( $c->req->param("food") );
2036 With this action, anyone can just come into the moose cage and feed the moose,
2037 which is a very dangerous thing. We need to restrict this action, so that only
2038 a qualified moose feeder can perform that action.
2040 The Authorization::Roles plugin let's us perform role based access control
2041 checks. Let's load it:
2044 Authentication # yadda yadda
2045 Authorization::Roles
2048 And now our action should look like this:
2050 sub feed_moose : Local {
2051 my ( $self, $c ) = @_;
2053 if ( $c->check_roles( "moose_feeder" ) ) {
2054 $c->model( "Moose" )->eat( $c->req->param("food") );
2056 $c->stash->{error} = "unauthorized";
2060 This checks C<< $c->user >>, and only if the user has B<all> the roles in the
2061 list, a true value is returned.
2063 C<check_roles> has a sister method, C<assert_roles>, which throws an exception
2064 if any roles are missing.
2066 Some roles that might actually make sense in, say, a forum application:
2080 each with a distinct task (system administration versus content administration).
2082 =head3 Access Control Lists
2084 Checking for roles all the time can be tedious and error prone.
2086 The Authorization::ACL plugin let's us declare where we'd like checks to be
2087 done automatically for us.
2089 For example, we may want to completely block out anyone who isn't a
2090 C<moose_feeder> from the entire C<MooseCage> controller:
2092 Zoo->deny_access_unless( "/moose_cage", [qw/moose_feeder/] );
2094 The role list behaves in the same way as C<check_roles>. However, the ACL
2095 plugin isn't limited to just interacting with the Roles plugin. We can use a
2096 code reference instead. For example, to allow either moose trainers or moose
2097 feeders into the moose cage, we can create a more complex check:
2099 Zoo->deny_access_unless( "/moose_cage", sub {
2101 $c->check_roles( "moose_trainer" ) || $c->check_roles( "moose_feeder" );
2104 The more specific a role, the earlier it will be checked. Let's say moose
2105 feeders are now restricted to only the C<feed_moose> action, while moose
2106 trainers get access everywhere:
2108 Zoo->deny_access_unless( "/moose_cage", [qw/moose_trainer/] );
2109 Zoo->allow_access_if( "/moose_cage/feed_moose", [qw/moose_feeder/]);
2111 When the C<feed_moose> action is accessed the second check will be made. If the
2112 user is a C<moose_feeder>, then access will be immediately granted. Otherwise,
2113 the next rule in line will be tested - the one checking for a C<moose_trainer>.
2114 If this rule is not satisfied, access will be immediately denied.
2116 Rules applied to the same path will be checked in the order they were added.
2118 Lastly, handling access denial events is done by creating an C<access_denied>
2121 sub access_denied : Private {
2122 my ( $self, $c, $action ) = @_;
2127 This action works much like auto, in that it is inherited across namespaces
2128 (not like object oriented code). This means that the C<access_denied> action
2129 which is B<nearest> to the action which was blocked will be triggered.
2131 If this action does not exist, an error will be thrown, which you can clean up
2132 in your C<end> private action instead.
2134 Also, it's important to note that if you restrict access to "/" then C<end>,
2135 C<default>, etc will also be restricted.
2137 MyApp->acl_allow_root_internals;
2139 will create rules that permit access to C<end>, C<begin>, and C<auto> in the
2140 root of your app (but not in any other controller).
2142 =head3 More Information
2144 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::Roles>
2145 L<http://search.cpan.org/perldoc?Catalyst::Plugin::Authorization::ACL>
2149 Sebastian Riedel, C<sri@oook.de>
2150 Danijel Milicevic, C<me@danijel.de>
2151 Viljo Marrandi, C<vilts@yahoo.com>
2152 Marcus Ramberg, C<mramberg@cpan.org>
2153 Jesse Sheidlower, C<jester@panix.com>
2154 Andy Grundman, C<andy@hybridized.org>
2155 Chisel Wright, C<pause@herlpacker.co.uk>
2156 Will Hawes, C<info@whawes.co.uk>
2157 Gavin Henry, C<ghenry@perl.me.uk>
2162 This program is free software, you can redistribute it and/or modify it
2163 under the same terms as Perl itself.