3 Catalyst::Manual::Tutorial::MoreCatalystBasics - Catalyst Tutorial - Part 3: More Catalyst Application Development Basics
8 This is B<Part 3 of 10> for the Catalyst tutorial.
10 L<Tutorial Overview|Catalyst::Manual::Tutorial>
16 L<Introduction|Catalyst::Manual::Tutorial::Intro>
20 L<Catalyst Basics|Catalyst::Manual::Tutorial::CatalystBasics>
24 B<More Catalyst Basics>
28 L<Basic CRUD|Catalyst::Manual::Tutorial::BasicCRUD>
32 L<Authentication|Catalyst::Manual::Tutorial::Authentication>
36 L<Authorization|Catalyst::Manual::Tutorial::Authorization>
40 L<Debugging|Catalyst::Manual::Tutorial::Debugging>
44 L<Testing|Catalyst::Manual::Tutorial::Testing>
48 L<Advanced CRUD|Catalyst::Manual::Tutorial::AdvancedCRUD>
52 L<Appendices|Catalyst::Manual::Tutorial::Appendices>
59 This part of the tutorial builds on the work done in Part 2 to explore
60 some features that are more typical of "real world" web applications.
61 From this part of the tutorial onward, we will be building a simple
62 book database application. Although the application will be too
63 limited to be of use to anyone, it should provide a basic environment
64 where we can explore a variety of features used in virtually all web
67 You can checkout the source code for this example from the catalyst
68 subversion repository as per the instructions in
69 L<Catalyst::Manual::Tutorial::Intro|Catalyst::Manual::Tutorial::Intro>.
72 =head1 CREATE A NEW APPLICATION
74 The remainder of the tutorial will build an application called C<MyApp>.
75 First use the Catalyst C<catalyst.pl> script to initialize the framework
76 for the C<MyApp> application (make sure you aren't still inside the
77 directory of the C<Hello> application from the previous part of the
82 created "MyApp/script"
86 created "MyApp/script/myapp_create.pl"
89 This creates a similar skeletal structure to what we saw in Part 2 of
90 the tutorial, except with C<MyApp> and C<myapp> substituted for
91 C<Hello> and C<hello>.
94 =head1 EDIT THE LIST OF CATALYST PLUGINS
96 One of the greatest benefits of Catalyst is that it has such a large
97 library of plugins and base classes available. Plugins are used to
98 seamlessly integrate existing Perl modules into the overall Catalyst
99 framework. In general, they do this by adding additional methods to the
100 C<context> object (generally written as C<$c>) that Catalyst passes to
101 every component throughout the framework.
103 By default, Catalyst enables three plugins/flags:
111 Enables the Catalyst debug output you saw when we started the
112 C<script/myapp_server.pl> development server earlier. You can remove
113 this item when you place your application into production.
115 As you may have noticed, C<-Debug> is not a plugin, but a I<flag>.
116 Although most of the items specified on the C<__PACKAGE__-E<gt>setup>
117 line of your application class will be plugins, Catalyst supports a
118 limited number of flag options (of these, C<-Debug> is the most
119 common). See the documentation for C<Catalyst.pm> to get details on
120 other flags (currently C<-Engine>, C<-Home>, and C<-Log>).
122 If you prefer, you can use the C<$c-E<gt>debug> method to enable debug
125 B<TIP>: Depending on your needs, it can be helpful to permanently
126 remove C<-Debug> from C<lib/MyApp.pm> and then use the C<-d> option
127 to C<script/myapp_server.pl> to re-enable it just for the development
128 server. We will not be using that approach in the tutorial, but feel
129 free to make use of it in your own projects.
133 L<Catalyst::Plugin::ConfigLoader|Catalyst::Plugin::ConfigLoader>
135 C<ConfigLoader> provides an automatic way to load configurable
136 parameters for your application from a central
137 L<Config::General|Config::General> file (versus having the values
138 hard-coded inside your Perl modules). Config::General uses syntax
139 very similar to Apache configuration files. We will see how to use
140 this feature of Catalyst during the authentication and authorization
141 sections (Part 5 and Part 6).
143 B<IMPORTANT NOTE:> If you are using a version of
144 L<Catalyst::Devel|Catalyst::Devel> prior to version 1.06, you need to
145 be aware that Catalyst changed from a default format of YAML to the
146 more straightforward C<Config::General> format. This tutorial use the
147 newer C<myapp.conf> configuration file for C<Config::General> instead
148 of C<myapp.yml> for YAML. However, Catalyst has long supported both
149 formats and Catalyst will automatically use either C<myapp.conf> or
150 C<myapp.yml> (or any other format supported by
151 L<Catalyst::Plugin::ConfigLoader|Catalyst::Plugin::ConfigLoader> and
152 L<Config::Any|Config::Any>). If you are using a versions of
153 Catalyst::Devel prior to 1.06, you can convert to the newer format by
154 simply creating the C<myapp.conf> file manually and deleting
155 C<myapp.yml>. The default contents of C<myapp.conf> should only
156 consist of one line: C<name MyApp>.
158 B<TIP>: This script can be useful for converting between configuration
161 perl -Ilib -e 'use MyApp; use Config::General;
162 Config::General->new->save_file("myapp.conf", MyApp->config);'
164 B<NOTE:> The default C<myapp.conf> should look like:
170 L<Catalyst::Plugin::Static::Simple|Catalyst::Plugin::Static::Simple>
172 C<Static::Simple> provides an easy method of serving static content such
173 as images and CSS files under the development server.
177 For our application, we want to add one new plugin into the mix. To
178 do this, edit C<lib/MyApp.pm> (this file is generally referred to as
179 your I<application class>) and delete the line with:
181 __PACKAGE__->setup(qw/-Debug ConfigLoader Static::Simple/);
183 Then replace it with:
185 __PACKAGE__->setup(qw/
193 B<Note:> Recent versions of C<Catalyst::Devel> have used a variety of
194 techniques to load these plugins/flags. If you are following along in
195 Ubuntu 8.10, you should have C<Catalyst::Devel> v1.07 and see the
196 default code shown above. If you are using v1.08, you should see the
197 following by default:
199 use Catalyst qw/-Debug
203 __PACKAGE__->setup();
205 Don't let these variations confuse you -- they all accomplish the same
208 This tells Catalyst to start using one new plugin,
209 L<Catalyst::Plugin::StackTrace|Catalyst::Plugin::StackTrace>, to add a
210 stack trace to the standard Catalyst "debug screen" (the screen
211 Catalyst sends to your browser when an error occurs). Be aware that
212 L<StackTrace|Catalyst::Plugin::StackTrace> output appears in your
213 browser, not in the console window from which you're running your
214 application, which is where logging output usually goes.
222 C<__PACKAGE__> is just a shorthand way of referencing the name of the
223 package where it is used. Therefore, in C<MyApp.pm>, C<__PACKAGE__>
224 is equivalent to C<MyApp>.
228 You will want to disable L<StackTrace|Catalyst::Plugin::StackTrace>
229 before you put your application into production, but it can be helpful
234 When specifying plugins on the C<__PACKAGE__-E<gt>setup> line, you can
235 omit C<Catalyst::Plugin::> from the name. Additionally, you can
236 spread the plugin names across multiple lines as shown here, or place
237 them all on one (or more) lines as with the default configuration.
242 =head1 CREATE A CATALYST CONTROLLER
244 As discussed earlier, controllers are where you write methods that
245 interact with user input. Typically, controller methods respond to
246 C<GET> and C<POST> messages from the user's web browser.
248 Use the Catalyst C<create> script to add a controller for book-related
251 $ script/myapp_create.pl controller Books
252 exists "/home/me/MyApp/script/../lib/MyApp/Controller"
253 exists "/home/me/MyApp/script/../t"
254 created "/home/me/MyApp/script/../lib/MyApp/Controller/Books.pm"
255 created "/home/me/MyApp/script/../t/controller_Books.t"
257 Then edit C<lib/MyApp/Controller/Books.pm> (as discussed in Part 2 of
258 the Tutorial, Catalyst has a separate directory under C<lib/MyApp> for
259 each of the three parts of MVC: C<Model>, C<View>, and C<Controller>)
260 and add the following method to the controller:
264 Fetch all book objects and pass to books/list.tt2 in stash to be displayed
269 # Retrieve the usual Perl OO '$self' for this object. $c is the Catalyst
270 # 'Context' that's used to 'glue together' the various components
271 # that make up the application
274 # Retrieve all of the book records as book model objects and store in the
275 # stash where they can be accessed by the TT template
276 # $c->stash->{books} = [$c->model('DB::Books')->all];
277 # But, for now, use this code until we create the model later
278 $c->stash->{books} = '';
280 # Set the TT template to use. You will almost always want to do this
281 # in your action methods (action methods respond to user input in
283 $c->stash->{template} = 'books/list.tt2';
286 B<TIP>: See Appendix 1 for tips on removing the leading spaces when
287 cutting and pasting example code from POD-based documents.
289 Programmers experienced with object-oriented Perl should recognize
290 C<$self> as a reference to the object where this method was called.
291 On the other hand, C<$c> will be new to many Perl programmers who have
292 not used Catalyst before (it's sometimes written as C<$context>). The
293 Context object is automatically passed to all Catalyst components. It
294 is used to pass information between components and provide access to
295 Catalyst and plugin functionality.
297 Catalyst actions are regular Perl methods, but they make use
298 of attributes (the "C<: Local>" next to the "C<sub list>" in the code
299 above) to provide additional information to the Catalyst dispatcher
300 logic (note that the space between the colon and the attribute name is
301 optional... you will see them written both ways). Over time, the
302 recommended style for most Catalyst applications has changed:
306 =item * From "C<:Local>" and "C<:Private>"
308 =item * To "C<:Path>" and "C<:Args>"
310 =item * To "C<:Chained>"
314 Although all three styles work just fine, the newer forms offer more
315 advanced capbilities and allow you to be more expressive with the URIs
316 that your application uses.
318 Here is a quick summary of the most commonly used action types:
319 C<Local>, C<Private>, C<Path> and C<Chained>:
325 B<Local and Private> -- In the past, the majority of applications have
326 traditionally used C<Local> actions for items that respond to user
327 requests and C<Private> actions for those that do not directly respond
332 There are five types of build-in C<Private> actions: C<begin>,
333 C<end>, C<default>, C<index>, and C<auto>.
337 With C<begin>, C<end>, C<default>, C<index> private actions, only the
338 most specific action of each type will be called. For example, if you
339 define a C<begin> action in your controller it will I<override> a
340 C<begin> action in your application/root controller -- I<only> the
341 action in your controller will be called.
345 Unlike the other actions where only a single method is called for each
346 request, I<every> auto action along the chain of namespaces will be
347 called. Each C<auto> action will be called I<from the application/root
348 controller down through the most specific class>.
354 B<Path> -- C<Path> actions were the next style of action types to
355 become popular and essentially provide a limited subset of what can be
356 found done with Chained actions. You can match on different portions
357 of the URI (for example C<Path('list')> in
358 C<lib/MyApp/Controller/Books.pm> would match on the URL
359 C<http://localhost:3000/books/list> but C<Path('/list')> would match
360 on C<http://localhost:3000/list>) and it let's you be very specific with
361 what arguments each controller method will accept. See
362 L<Catalyst::Manual::Intro/Action_types> for more information and a few
367 B<Chained> -- Newer Catalyst applications tend to use the Chained
368 dispatch form of action types because of its power and flexibility.
369 It allows a series of controller methods to automatically be dispatched
370 to service a single user request. See
371 L<Catalyst::Manual::Tutorial::BasicCRUD|Catalyst::Manual::Tutorial::BasicCRUD>
372 and L<Catalyst::DispatchType::Chained|Catalyst::DispatchType::Chained>
373 for more information on chained actions.
377 You should refer to L<Catalyst::Manual::Intro/Action_types> for
378 additional information and for coverage of some lesser-used action
379 types not discussed here (C<Regex>, C<LocalRegex> and C<Global>).
382 =head1 CATALYST VIEWS
384 As mentioned in Part 2 of the tutorial, views are where you render
385 output, typically for display in the user's web browser (but also
386 possibly using other display output-generation systems). The code in
387 C<lib/MyApp/View> selects the I<type> of view to use, with the actual
388 rendering template found in the C<root> directory. As with virtually
389 every aspect of Catalyst, options abound when it comes to the specific
390 view technology you adopt inside your application. However, most
391 Catalyst applications use the Template Toolkit, known as TT (for more
392 information on TT, see L<http://www.template-toolkit.org>). Other
393 somewhat popular view technologies include Mason
394 (L<http://www.masonhq.com> and L<http://www.masonbook.com>) and
395 L<HTML::Template> (L<http://html-template.sourceforge.net>).
398 =head2 Create a Catalyst View
400 When using TT for the Catalyst view, there are two main helper scripts:
406 L<Catalyst::Helper::View::TT|Catalyst::Helper::View::TT>
410 L<Catalyst::Helper::View::TTSite|Catalyst::Helper::View::TTSite>
414 Both helpers are similar. C<TT> creates the C<lib/MyApp/View/TT.pm>
415 file and leaves the creation of any hierarchical template organization
416 entirely up to you. (It also creates a C<t/view_TT.t> file for testing;
417 test cases will be discussed in Part 8.) C<TTSite>, on the other hand,
418 creates a modular and hierarchical view layout with
419 separate Template Toolkit (TT) files for common header and footer
420 information, configuration values, a CSS stylesheet, and more.
422 While C<TTSite> was useful to bootstrap a project, its use is now
423 deprecated and to be considered historical. For most Catalyst
424 applications it adds redundant functionality and structure; many in the
425 Catalyst community recommend that it's easier to learn both Catalyst and
426 Template Toolkit if you use the more basic C<TT> approach.
427 Consequently, this tutorial will use "plain old TT."
429 Enter the following command to enable the C<TT> style of view
430 rendering for this tutorial:
432 $ script/myapp_create.pl view TT TT
433 exists "/home/me/MyApp/script/../lib/MyApp/View"
434 exists "/home/me/MyApp/script/../t"
435 created "/home/me/MyApp/script/../lib/MyApp/View/TT.pm"
436 created "/home/me/MyApp/script/../t/view_TT.t"
438 This simply creates a view called C<TT> (the second 'TT' argument) in
439 a file called C<TT.pm> (the first 'TT' argument). It is now up to you
440 to decide how you want to structure your view layout. For the
441 tutorial, we will start with a very simple TT template to initially
442 demonstrate the concepts, but quickly migrate to a more typical
443 "wrapper page" type of configuration (where the "wrapper" controls the
444 overall "look and feel" of your site from a single file or set of
447 Edit C<lib/MyApp/View/TT.pm> and you should see that the default
448 contents contains something similar to the following:
450 __PACKAGE__->config(TEMPLATE_EXTENSION => '.tt');
452 And update it to match:
455 # Change default TT extension
456 TEMPLATE_EXTENSION => '.tt2',
457 # Set the location for TT files
459 MyApp->path_to( 'root', 'src' ),
463 B<NOTE:> Make sure to add a comma after '.tt2' outside the single
466 This changes the default extension for Template Toolkit from '.tt' to
467 '.tt2' and changes the base directory for your template files from
468 C<root> to C<root/src>. These changes from the default are done mostly
469 to facilitate the application we're developing in this tutorial; as with
470 most things Perl, there's more than one way to do it...
473 =head2 Create a TT Template Page
475 First create a directory for book-related TT templates:
477 $ mkdir -p root/src/books
479 Then create C<root/src/books/list.tt2> in your editor and enter:
481 [% # This is a TT comment. The '-' at the end "chomps" the newline. You won't -%]
482 [% # see this "chomping" in your browser because HTML ignores blank lines, but -%]
483 [% # it WILL eliminate a blank line if you view the HTML source. It's purely -%]
484 [%- # optional, but both the beginning and the ending TT tags support chomping. -%]
486 [% # Provide a title -%]
487 [% META title = 'Book List' -%]
490 <tr><th>Title</th><th>Rating</th><th>Author(s)</th></tr>
491 [% # Display each book in a table row %]
492 [% FOREACH book IN books -%]
494 <td>[% book.title %]</td>
495 <td>[% book.rating %]</td>
500 As indicated by the inline comments above, the C<META title> line uses
501 TT's META feature to provide a title to the "wrapper" that we will
502 create later. Meanwhile, the C<FOREACH> loop iterates through each
503 C<book> model object and prints the C<title> and C<rating> fields.
505 If you are new to TT, the C<[%> and C<%]> tags are used to delimit TT
506 code. TT supports a wide variety of directives for "calling" other
507 files, looping, conditional logic, etc. In general, TT simplifies the
508 usual range of Perl operators down to the single dot (C<.>) operator.
509 This applies to operations as diverse as method calls, hash lookups, and
510 list index values (see
511 L<http://search.cpan.org/perldoc?Template::Manual::Variables>
512 for details and examples). In addition to the usual C<Template> module
513 Pod documentation, you can access the TT manual at
514 L<http://search.cpan.org/perldoc?Template::Manual>.
516 B<TIP:> While you can build all sorts of complex logic into your TT
517 templates, you should in general keep the "code" part of your templates
518 as simple as possible. If you need more complex logic, create helper
519 methods in your model that abstract out a set of code into a single call
520 from your TT template. (Note that the same is true of your controller
521 logic as well -- complex sections of code in your controllers should
522 often be pulled out and placed into your model objects.)
525 =head2 Test Run The Application
527 To test your work so far, first start the development server:
529 $ script/myapp_server.pl
531 Then point your browser to L<http://localhost:3000> and you should
532 still get the Catalyst welcome page. Next, change the URL in your
533 browser to L<http://localhost:3000/books/list>. If you have
534 everything working so far, you should see a web page that displays
535 nothing other than our column headers for "Title", "Rating", and
536 "Author(s)" -- we will not see any books until we get the database and
539 If you run into problems getting your application to run correctly, it
540 might be helpful to refer to some of the debugging techniques covered in
541 the L<Debugging|Catalyst::Manual::Tutorial::Debugging> part of the
545 =head1 CREATE A SQLITE DATABASE
547 In this step, we make a text file with the required SQL commands to
548 create a database table and load some sample data. We will use SQLite,
549 a popular database that is lightweight and easy to use. Open
550 C<myapp01.sql> in your editor and enter:
553 -- Create a very simple database to hold book and author information
556 id INTEGER PRIMARY KEY,
560 -- 'book_authors' is a many-to-many join table between books & authors
561 CREATE TABLE book_authors (
564 PRIMARY KEY (book_id, author_id)
566 CREATE TABLE authors (
567 id INTEGER PRIMARY KEY,
572 --- Load some sample data
574 INSERT INTO books VALUES (1, 'CCSP SNRS Exam Certification Guide', 5);
575 INSERT INTO books VALUES (2, 'TCP/IP Illustrated, Volume 1', 5);
576 INSERT INTO books VALUES (3, 'Internetworking with TCP/IP Vol.1', 4);
577 INSERT INTO books VALUES (4, 'Perl Cookbook', 5);
578 INSERT INTO books VALUES (5, 'Designing with Web Standards', 5);
579 INSERT INTO authors VALUES (1, 'Greg', 'Bastien');
580 INSERT INTO authors VALUES (2, 'Sara', 'Nasseh');
581 INSERT INTO authors VALUES (3, 'Christian', 'Degu');
582 INSERT INTO authors VALUES (4, 'Richard', 'Stevens');
583 INSERT INTO authors VALUES (5, 'Douglas', 'Comer');
584 INSERT INTO authors VALUES (6, 'Tom', 'Christiansen');
585 INSERT INTO authors VALUES (7, 'Nathan', 'Torkington');
586 INSERT INTO authors VALUES (8, 'Jeffrey', 'Zeldman');
587 INSERT INTO book_authors VALUES (1, 1);
588 INSERT INTO book_authors VALUES (1, 2);
589 INSERT INTO book_authors VALUES (1, 3);
590 INSERT INTO book_authors VALUES (2, 4);
591 INSERT INTO book_authors VALUES (3, 5);
592 INSERT INTO book_authors VALUES (4, 6);
593 INSERT INTO book_authors VALUES (4, 7);
594 INSERT INTO book_authors VALUES (5, 8);
596 Then use the following command to build a C<myapp.db> SQLite database:
598 $ sqlite3 myapp.db < myapp01.sql
600 If you need to create the database more than once, you probably want to
601 issue the C<rm myapp.db> command to delete the database before you use
602 the C<sqlite3 myapp.db E<lt> myapp01.sql> command.
604 Once the C<myapp.db> database file has been created and initialized, you
605 can use the SQLite command line environment to do a quick dump of the
610 Enter ".help" for instructions
611 sqlite> select * from books;
612 1|CCSP SNRS Exam Certification Guide|5
613 2|TCP/IP Illustrated, Volume 1|5
614 3|Internetworking with TCP/IP Vol.1|4
616 5|Designing with Web Standards|5
622 $ sqlite3 myapp.db "select * from books"
623 1|CCSP SNRS Exam Certification Guide|5
624 2|TCP/IP Illustrated, Volume 1|5
625 3|Internetworking with TCP/IP Vol.1|4
627 5|Designing with Web Standards|5
629 As with most other SQL tools, if you are using the full "interactive"
630 environment you need to terminate your SQL commands with a ";" (it's not
631 required if you do a single SQL statement on the command line). Use
632 ".q" to exit from SQLite from the SQLite interactive mode and return to
633 your OS command prompt.
635 For using other databases, such as PostgreSQL or MySQL, see
636 L<Appendix 2|Catalyst::Manual::Tutorial::Appendices>.
638 =head1 DATABASE ACCESS WITH C<DBIx::Class>
640 Catalyst can be used with virtually any form of persistent datastore
641 available via Perl. For example,
642 L<Catalyst::Model::DBI|Catalyst::Model::DBI> can be used to easily
643 access databases through the traditional Perl C<DBI> interface. However,
644 most Catalyst applications use some form of ORM technology to
645 automatically create and save model objects as they are used. Although
646 L<Class::DBI|Class::DBI> has been a popular choice in the past, Matt
647 Trout's L<DBIx::Class|DBIx::Class> (abbreviated as "DBIC") has rapidly
648 emerged as the Perl-based ORM technology of choice. Most new Catalyst
649 applications rely on DBIC, as will this tutorial.
652 =head2 Create a Dynamic DBIC Model
654 Use the C<create=dynamic> model helper option to build a model that
655 dynamically reads your database structure every time the application
658 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema create=dynamic dbi:SQLite:myapp.db
659 exists "/home/me/MyApp/script/../lib/MyApp/Model"
660 exists "/home/me/MyApp/script/../t"
661 exists "/home/me/MyApp/script/../lib/MyApp"
662 created "/home/me/MyApp/script/../lib/MyApp/Schema.pm"
663 created "/home/me/MyApp/script/../lib/MyApp/Model/DB.pm"
664 created "/home/me/MyApp/script/../t/model_DB.t"
667 C<DB> is the name of the model class to be created by the helper in
668 C<lib/MyApp/Model>. C<DBIC::Schema> is the type of the model to
669 create. C<MyApp::Schema> is the name of the DBIC schema file written
670 to C<lib/MyApp/Schema.pm>. Because we specified C<create=dynamic> to
672 L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> to
673 dynamically load the schema information from the database every time
674 the application starts. DBIC uses the schema to load other classes
675 that represent the tables in your database (DBIC refers to these
676 "table objects" as "result sources," see
677 L<DBIx::Class::ResultSource|DBIx::Class::ResultSource>). And finally,
678 C<dbi:SQLite:myapp.db> is the standard DBI connect string for use with
681 B<NOTE:> Although the C<create=dynamic> option to the DBIC helper
682 makes for a nifty demonstration, is only really suitable for very
683 small applications. After this demonstration, you should almost always
684 use the C<create=static> option that we switch to below.
687 =head1 ENABLE THE MODEL IN THE CONTROLLER
689 Open C<lib/MyApp/Controller/Books.pm> and un-comment the model code we
690 left disabled earlier (un-comment the line containing
691 C<[$c-E<gt>model('DB::Books')-E<gt>all]> and delete the next 2 lines):
695 Fetch all book objects and pass to books/list.tt2 in stash to be displayed
700 # Retrieve the usual Perl OO '$self' for this object. $c is the Catalyst
701 # 'Context' that's used to 'glue together' the various components
702 # that make up the application
705 # Retrieve all of the book records as book model objects and store in the
706 # stash where they can be accessed by the TT template
707 $c->stash->{books} = [$c->model('DB::Books')->all];
709 # Set the TT template to use. You will almost always want to do this
710 # in your action methods (action methods respond to user input in
712 $c->stash->{template} = 'books/list.tt2';
715 B<TIP>: You may see the C<$c-E<gt>model('DB::Book')> un-commented
716 above written as C<$c-E<gt>model('DB')-E<gt>resultset('Book')>. The
717 two are equivalent. Either way, C<$c-E<gt>model> returns a
718 L<DBIx::Class::ResultSet|DBIx::Class::ResultSet> which handles queries
719 against the database and iterating over the set of results that are
722 We are using the C<-E<gt>all> to fetch all of the books. DBIC
723 supports a wide variety of more advanced operations to easily do
724 things like filtering and sorting the results. For example, the
725 following could be used to sort the results by descending title:
727 $c->model('DB::Books')->search({}, {order_by => 'title DESC'});
729 Some other examples are provided in
730 L<DBIx::Class::Manual::Cookbook/Complex WHERE clauses>, with
731 additional information found at L<DBIx::Class::ResultSet/search>,
732 L<DBIx::Class::Manual::FAQ/Searching>,
733 L<DBIx::Class::Manual::Intro|DBIx::Class::Manual::Intro>
734 and L<Catalyst::Model::DBIC::Schema|Catalyst::Model::DBIC::Schema>.
737 =head2 Test Run The Application
739 First, let's enable an environment variable option that causes
740 DBIx::Class to dump the SQL statements it's using to access the database
741 (this option can provide extremely helpful troubleshooting information):
743 $ export DBIC_TRACE=1
745 This assumes you are using BASH as your shell -- adjust accordingly if
746 you are using a different shell (for example, under tcsh, use
747 C<setenv DBIC_TRACE 1>).
749 B<NOTE:> You can also set this in your code using
750 C<$class-E<gt>storage-E<gt>debug(1);>. See
751 L<DBIx::Class::Manual::Troubleshooting> for details (including options
752 to log to file instead of displaying to the Catalyst development server
755 Then launch the Catalyst development server. The log output should
756 display something like:
758 $script/myapp_server.pl
759 [debug] Debug messages enabled
760 [debug] Statistics enabled
761 [debug] Loaded plugins:
762 .----------------------------------------------------------------------------.
763 | Catalyst::Plugin::ConfigLoader 0.20 |
764 | Catalyst::Plugin::StackTrace 0.08 |
765 | Catalyst::Plugin::Static::Simple 0.20 |
766 '----------------------------------------------------------------------------'
768 [debug] Loaded dispatcher "Catalyst::Dispatcher"
769 [debug] Loaded engine "Catalyst::Engine::HTTP"
770 [debug] Found home "/home/me/MyApp"
771 [debug] Loaded Config "/home/me/MyApp/myapp.conf"
772 [debug] Loaded components:
773 .-----------------------------------------------------------------+----------.
775 +-----------------------------------------------------------------+----------+
776 | MyApp::Controller::Books | instance |
777 | MyApp::Controller::Root | instance |
778 | MyApp::Model::DB | instance |
779 | MyApp::Model::DB::Authors | class |
780 | MyApp::Model::DB::BookAuthors | class |
781 | MyApp::Model::DB::Books | class |
782 | MyApp::View::TT | instance |
783 '-----------------------------------------------------------------+----------'
785 [debug] Loaded Private actions:
786 .----------------------+--------------------------------------+--------------.
787 | Private | Class | Method |
788 +----------------------+--------------------------------------+--------------+
789 | /default | MyApp::Controller::Root | default |
790 | /end | MyApp::Controller::Root | end |
791 | /index | MyApp::Controller::Root | index |
792 | /books/index | MyApp::Controller::Books | index |
793 | /books/list | MyApp::Controller::Books | list |
794 '----------------------+--------------------------------------+--------------'
796 [debug] Loaded Path actions:
797 .-------------------------------------+--------------------------------------.
799 +-------------------------------------+--------------------------------------+
802 | /books | /books/index |
803 | /books/list | /books/list |
804 '-------------------------------------+--------------------------------------'
806 [info] MyApp powered by Catalyst 5.7014
807 You can connect to your server at http://localhost:3000
809 B<NOTE:> Be sure you run the C<script/myapp_server.pl> command from
810 the 'base' directory of your application, not inside the C<script>
811 directory itself or it will not be able to locate the C<myapp.db>
812 database file. You can use a fully qualified or a relative path to
813 locate the database file, but we did not specify that when we ran the
814 model helper earlier.
816 Some things you should note in the output above:
822 Catalyst::Model::DBIC::Schema dynamically created three model classes,
823 one to represent each of the three tables in our database
824 (C<MyApp::Model::DB::Authors>, C<MyApp::Model::DB::BookAuthors>,
825 and C<MyApp::Model::DB::Books>).
829 The "list" action in our Books controller showed up with a path of
834 Point your browser to L<http://localhost:3000> and you should still get
835 the Catalyst welcome page.
837 Next, to view the book list, change the URL in your browser to
838 L<http://localhost:3000/books/list>. You should get a list of the five
839 books loaded by the C<myapp01.sql> script above without any formatting.
840 The rating for each book should appear on each row, but the "Author(s)"
841 column will still be blank (we will fill that in later).
843 Also notice in the output of the C<script/myapp_server.pl> that DBIC
844 used the following SQL to retrieve the data:
846 SELECT me.id, me.title, me.rating FROM books me
848 because we enabled DBIC_TRACE.
850 You now have the beginnings of a simple but workable web application.
851 Continue on to future sections and we will develop the application
855 =head1 CREATE A WRAPPER FOR THE VIEW
857 When using TT, you can (and should!) create a wrapper that will
858 literally wrap content around each of your templates. This is
859 certainly useful as you have one main source for changing things that
860 will appear across your entire site/application instead of having to
861 edit many individual files.
864 =head2 Configure TT.pm For The Wrapper
866 In order to create a wrapper, you must first edit your TT view and
867 tell it where to find your wrapper file. Your TT view is located in
868 C<lib/MyApp/View/TT.pm>.
870 Edit C<lib/MyApp/View/TT.pm> and change it to match the following:
873 # Change default TT extension
874 TEMPLATE_EXTENSION => '.tt2',
875 # Set the location for TT files
877 MyApp->path_to( 'root', 'src' ),
879 # Set to 1 for detailed timer stats in your HTML as comments
881 # This is your wrapper template located in the 'root/src'
882 WRAPPER => 'wrapper.tt2',
886 =head2 Create the Wrapper Template File and Stylesheet
888 Next you need to set up your wrapper template. Basically, you'll want
889 to take the overall layout of your site and put it into this file.
890 For the tutorial, open C<root/src/wrapper.tt2> and input the following:
892 <?xml version="1.0" encoding="UTF-8"?>
893 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
894 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
896 <title>[% template.title or "My Catalyst App!" %]</title>
897 <link rel="stylesheet" href="[% c.uri_for('/static/css/main.css') %]" />
903 [%# Your logo could go here -%]
904 <img src="[% c.uri_for('/static/images/btn_88x31_powered.png') %]" />
905 [%# Insert the page title -%]
906 <h1>[% template.title or site.title %]</h1>
913 <li><a href="[% c.uri_for('/books/list') %]">Home</a></li>
914 <li><a href="[% c.uri_for('/') %]" title="Catalyst Welcome Page">Welcome</a></li>
915 <li><a href="mailto:nobody@nowhere.com" title="Contact Us">Contact Us</a></li>
917 </div><!-- end menu -->
920 [%# Status and error messages %]
921 <span class="message">[% status_msg %]</span>
922 <span class="error">[% error_msg %]</span>
923 [%# This is where TT will stick all of your template's contents. -%]
925 </div><!-- end content -->
926 </div><!-- end bodyblock -->
928 <div id="footer">Copyright (c) your name goes here</div>
929 </div><!-- end outer -->
934 Notice the status and error message sections in the code above:
936 <span class="status">[% status_msg %]</span>
937 <span class="error">[% error_msg %]</span>
939 If we set either message in the Catalyst stash (e.g.,
940 C<$c-E<gt>stash-E<gt>{status_msg} = 'Request was successful!'>) it
941 will be displayed whenever any view used by that request is rendered.
942 The C<message> and C<error> CSS styles can be customized to suit your
943 needs in the C<root/static/css/main.css> file we create below.
951 The Catalyst stash only lasts for a single HTTP request. If
952 you need to retain information across requests you can use
953 L<Catalyst::Plugin::Session|Catalyst::Plugin::Session> (we will use
954 Catalyst sessions in the Authentication part of the tutorial).
958 Although it is beyond the scope of this tutorial, you may wish to use
959 a JavaScript or AJAX tool such as jQuery (L<http://www.jquery.com>) or
960 Dojo (L<http://www.dojotoolkit.org>).
965 =head3 Create A Basic Stylesheet
967 First create a central location for stylesheets under the static
970 $ mkdir root/static/css
972 Then open the file C<root/static/css/main.css> (the file referenced in
973 the stylesheet href link of our wrapper above) and add the following
992 background-color: #ddd;
998 padding: 0 0 50% 5px;
1000 background-color: #ddd;
1013 You may wish to check out a "CSS Framework" like Emastic
1014 (L<http://code.google.com/p/emastic/>) as a way to quickly
1015 provide lots of high-quality CSS functionality.
1018 =head2 Test Run The Application
1020 Restart the development server and hit "Reload" in your web browser
1021 and you should now see a formatted version of our basic book list.
1022 Although our wrapper and stylesheet are obviously very simple, you
1023 should see how it allows us to control the overall look of an entire
1024 website from two central files. To add new pages to the site, just
1025 provide a template that fills in the C<content> section of our wrapper
1026 template -- the wrapper will provide the overall feel of the page.
1029 =head1 A STATIC DATABASE MODEL WITH C<DBIx::Class>
1031 =head2 Create Static DBIC Schema Files
1033 Unlike the previous DBIC section where we had C<create=dynamic>
1034 automatically discover the structure of the database every time the
1035 application started, here we will use static schema files for more
1036 control. This is typical of most "real world" applications.
1038 One option would be to manually create a separate schema file for each
1039 table in the database, however, lets use the same
1040 L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> used
1041 earlier with C<create=dynamic> to build the static files for us.
1042 First, lets remove the schema file created earlier:
1044 $ rm lib/MyApp/Schema.pm
1046 Now regenerate the schema using the C<create=static> option:
1048 $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema create=static dbi:SQLite:myapp.db
1049 exists "/home/kclark/dev/MyApp/script/../lib/MyApp/Model"
1050 exists "/home/kclark/dev/MyApp/script/../t"
1051 Dumping manual schema for MyApp::Schema to directory /home/kclark/dev/MyApp/script/../lib ...
1052 Schema dump completed.
1053 exists "/home/kclark/dev/MyApp/script/../lib/MyApp/Model/DB.pm"
1055 We could have also deleted C<lib/MyApp/Model/DB.pm>, but it would
1056 have regenerated the same file (note the C<exists> in the output above).
1057 If you take a look at C<lib/MyApp/Model/DB.pm>, it simply contains
1058 a reference to the actual schema file in C<lib/MyApp/Schema.pm>
1059 along with the database connect string.
1061 If you look in the C<lib/MyApp/Schema.pm> file, you will find that it
1063 L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> as its base
1064 class (L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> is
1065 only being used by the helper to load the schema once and then create
1066 the static files for us) and C<Schema.pm> only contains a call to the
1067 C<load_classes> method. You will also find that C<lib/MyApp>
1068 contains a C<Schema> subdirectory, with one file inside this directory
1069 for each of the tables in our simple database (C<Authors.pm>,
1070 C<BookAuthors.pm>, and C<Books.pm>). These three files were created
1071 based on the information found by
1072 L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> as the
1075 The idea with all of the files created under C<lib/MyApp/Schema> by
1076 the C<create=static> option is to only edit the files below the C<# DO
1077 NOT MODIFY THIS OR ANYTHING ABOVE!> warning. If you place all of your
1078 changes below that point in the file, you can regenerate the
1079 automatically created information at the top of each file should your
1080 database structure get updated.
1082 Also note the "flow" of the model information across the various files
1083 and directories. Catalyst will initially load the model from
1084 C<lib/MyApp/Model/DB.pm>. This file contains a reference to
1085 C<lib/MyApp/Schema.pm>, so that file is loaded next. Finally,
1086 the call to C<load_classes> in C<Schema.pm> will load each of the
1087 table-specific "results source" files from the C<lib/MyApp/Schema>
1088 subdirectory. These three table-specific DBIC schema files will then be
1089 used to create three table-specific Catalyst models every time the
1090 application starts (you can see these three model files listed in
1091 the debug output generated when you launch the application).
1094 =head2 Updating the Generated DBIC Schema Files
1096 Let's manually add some relationship information to the auto-generated
1097 schema files. First edit C<lib/MyApp/Schema/Books.pm> and
1098 add the following text below the C<# You can replace this text...>
1102 # Set relationships:
1107 # 1) Name of relationship, DBIC will create accessor with this name
1108 # 2) Name of the model class referenced by this relationship
1109 # 3) Column name in *foreign* table
1110 __PACKAGE__->has_many(book_authors => 'MyApp::Schema::BookAuthors', 'book_id');
1114 # 1) Name of relationship, DBIC will create accessor with this name
1115 # 2) Name of has_many() relationship this many_to_many() is shortcut for
1116 # 3) Name of belongs_to() relationship in model class of has_many() above
1117 # You must already have the has_many() defined to use a many_to_many().
1118 __PACKAGE__->many_to_many(authors => 'book_authors', 'author');
1121 B<Note:> Be careful to put this code I<above> the C<1;> at the end of the
1122 file. As with any Perl package, we need to end the last line with
1123 a statement that evaluates to C<true>. This is customarily done with
1124 C<1;> on a line by itself.
1126 This code defines both a C<has_many> and a C<many_to_many> relationship.
1127 The C<many_to_many> relationship is optional, but it makes it easier to
1128 map a book to its collection of authors. Without it, we would have to
1129 "walk" though the C<book_authors> table as in
1130 C<$book-E<gt>book_authors-E<gt>first-E<gt>author-E<gt>last_name>
1131 (we will see examples on how to use DBIC objects in your code soon,
1132 but note that because C<$book-E<gt>book_authors> can return multiple
1133 authors, we have to use C<first> to display a single author).
1134 C<many_to_many> allows us to use the shorter
1135 C<$book-E<gt>authors-E<gt>first-E<gt>last_name>.
1136 Note that you cannot define a C<many_to_many> relationship without
1137 also having the C<has_many> relationship in place.
1139 Then edit C<lib/MyApp/Schema/Authors.pm> and add relationship
1140 information as follows (again, be careful to put in above the C<1;> but
1141 below the C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!> comment):
1144 # Set relationships:
1149 # 1) Name of relationship, DBIC will create accessor with this name
1150 # 2) Name of the model class referenced by this relationship
1151 # 3) Column name in *foreign* table
1152 __PACKAGE__->has_many(book_author => 'MyApp::Schema::BookAuthors', 'author_id');
1156 # 1) Name of relationship, DBIC will create accessor with this name
1157 # 2) Name of has_many() relationship this many_to_many() is shortcut for
1158 # 3) Name of belongs_to() relationship in model class of has_many() above
1159 # You must already have the has_many() defined to use a many_to_many().
1160 __PACKAGE__->many_to_many(books => 'book_author', 'book');
1162 Finally, do the same for the "join table,"
1163 C<lib/MyApp/Schema/BookAuthors.pm>:
1166 # Set relationships:
1171 # 1) Name of relationship, DBIC will create accessor with this name
1172 # 2) Name of the model class referenced by this relationship
1173 # 3) Column name in *this* table
1174 __PACKAGE__->belongs_to(book => 'MyApp::Schema::Books', 'book_id');
1178 # 1) Name of relationship, DBIC will create accessor with this name
1179 # 2) Name of the model class referenced by this relationship
1180 # 3) Column name in *this* table
1181 __PACKAGE__->belongs_to(author => 'MyApp::Schema::Authors', 'author_id');
1184 =head2 Run The Application
1186 Run the Catalyst "demo server" script with the C<DBIC_TRACE> option
1187 (it might still be enabled from earlier in the tutorial, but here
1188 is an alternate way to specify the option just in case):
1190 $ DBIC_TRACE=1 script/myapp_server.pl
1192 Make sure that the application loads correctly and that you see the
1193 three dynamically created model class (one for each of the
1194 table-specific schema classes we created).
1196 Then hit the URL L<http://localhost:3000/books/list> and be sure that
1197 the book list is displayed via the relationships established above. You
1198 can leave the development server running for the next step if you wish.
1200 B<Note:> You will not see the authors yet because the view does not yet
1201 use the new relations. Read on to the next section where we update the
1202 template to do that.
1205 =head1 UPDATING THE VIEW
1207 Let's add a new column to our book list page that takes advantage of
1208 the relationship information we manually added to our schema files
1209 in the previous section. Edit C<root/src/books/list.tt2> add add the
1210 following code below the existing table cell that contains
1211 C<book.rating> (IOW, add a new table cell below the existing two
1215 [% # First initialize a TT variable to hold a list. Then use a TT FOREACH -%]
1216 [% # loop in 'side effect notation' to load just the last names of the -%]
1217 [% # authors into the list. Note that the 'push' TT vmethod does not print -%]
1218 [% # a value, so nothing will be printed here. But, if you have something -%]
1219 [% # in TT that does return a method and you don't want it printed, you -%]
1220 [% # can: 1) assign it to a bogus value, or 2) use the CALL keyword to -%]
1221 [% # call it and discard the return value. -%]
1222 [% tt_authors = [ ];
1223 tt_authors.push(author.last_name) FOREACH author = book.authors %]
1224 [% # Now use a TT 'virtual method' to display the author count in parens -%]
1225 [% # Note the use of the TT filter "| html" to escape dangerous characters -%]
1226 ([% tt_authors.size | html %])
1227 [% # Use another TT vmethod to join & print the names & comma separators -%]
1228 [% tt_authors.join(', ') | html %]
1231 Then hit "Reload" in your browser (note that you don't need to reload
1232 the development server or use the C<-r> option when updating TT
1233 templates) and you should now see the number of authors each book has
1234 along with a comma-separated list of the authors' last names. (If you
1235 didn't leave the development server running from the previous step,
1236 you will obviously need to start it before you can refresh your
1239 If you are still running the development server with C<DBIC_TRACE>
1240 enabled, you should also now see five more C<SELECT> statements in the
1241 debug output (one for each book as the authors are being retrieved by
1244 SELECT me.id, me.title, me.rating FROM books me:
1245 SELECT me.book_id, me.author_id FROM book_authors me WHERE ( me.book_id = ? ): '1'
1246 SELECT me.book_id, me.author_id FROM book_authors me WHERE ( me.book_id = ? ): '2'
1247 SELECT me.book_id, me.author_id FROM book_authors me WHERE ( me.book_id = ? ): '3'
1248 SELECT me.book_id, me.author_id FROM book_authors me WHERE ( me.book_id = ? ): '4'
1249 SELECT me.book_id, me.author_id FROM book_authors me WHERE ( me.book_id = ? ): '5'
1251 Also note in C<root/src/books/list.tt2> that we are using "| html", a
1252 type of TT filter, to escape characters such as E<lt> and E<gt> to <
1253 and > and avoid various types of dangerous hacks against your
1254 application. In a real application, you would probably want to put
1255 "| html" at the end of every field where a user has control over the
1256 information that can appear in that field (and can therefore inject
1257 markup or code if you don't "neutralize" those fields). In addition to
1258 "| html", Template Toolkit has a variety of other useful filters that
1259 can found in the documentation for
1260 L<Template::Filters|Template::Filters>.
1263 =head1 RUNNING THE APPLICATION FROM THE COMMAND LINE
1265 In some situations, it can be useful to run your application and
1266 display a page without using a browser. Catalyst lets you do this
1267 using the C<scripts/myapp_test.pl> script. Just supply the URL you
1268 wish to display and it will run that request through the normal
1269 controller dispatch logic and use the appropriate view to render the
1270 output (obviously, complex pages may dump a lot of text to your
1271 terminal window). For example, if you type:
1273 $ script/myapp_test.pl "/books/list"
1275 You should get the same text as if you visited
1276 L<http://localhost:3000/books/list> with the normal development server
1277 and asked your browser to view the page source.
1280 =head1 OPTIONAL INFORMATION
1282 B<NOTE: The rest of this part of the tutorial is optional. You can
1283 skip to Part 4, L<Basic CRUD|Catalyst::Manual::Tutorial::BasicCRUD>,
1286 =head2 Using C<RenderView> for the Default View
1288 Once your controller logic has processed the request from a user, it
1289 forwards processing to your view in order to generate the appropriate
1290 response output. Catalyst uses
1291 L<Catalyst::Action::RenderView|Catalyst::Action::RenderView> by
1292 default to automatically performs this operation. If you look in
1293 C<lib/MyApp/Controller/Root.pm>, you should see the empty
1294 definition for the C<sub end> method:
1296 sub end : ActionClass('RenderView') {}
1298 The following bullet points provide a quick overview of the
1299 C<RenderView> process:
1305 C<Root.pm> is designed to hold application-wide logic.
1309 At the end of a given user request, Catalyst will call the most specific
1310 C<end> method that's appropriate. For example, if the controller for a
1311 request has an C<end> method defined, it will be called. However, if
1312 the controller does not define a controller-specific C<end> method, the
1313 "global" C<end> method in C<Root.pm> will be called.
1317 Because the definition includes an C<ActionClass> attribute, the
1318 L<Catalyst::Action::RenderView|Catalyst::Action::RenderView> logic
1319 will be executed B<after> any code inside the definition of C<sub end>
1320 is run. See L<Catalyst::Manual::Actions|Catalyst::Manual::Actions>
1321 for more information on C<ActionClass>.
1325 Because C<sub end> is empty, this effectively just runs the default
1326 logic in C<RenderView>. However, you can easily extend the
1327 C<RenderView> logic by adding your own code inside the empty method body
1328 (C<{}>) created by the Catalyst Helpers when we first ran the
1329 C<catalyst.pl> to initialize our application. See
1330 L<Catalyst::Action::RenderView|Catalyst::Action::RenderView> for more
1331 detailed information on how to extended C<RenderView> in C<sub end>.
1336 =head2 Using The Default Template Name
1338 By default, C<Catalyst::View::TT> will look for a template that uses the
1339 same name as your controller action, allowing you to save the step of
1340 manually specifying the template name in each action. For example, this
1341 would allow us to remove the
1342 C<$c-E<gt>stash-E<gt>{template} = 'books/list.tt2';> line of our
1343 C<list> action in the Books controller. Open
1344 C<lib/MyApp/Controller/Books.pm> in your editor and comment out this line
1345 to match the following (only the C<$c-E<gt>stash-E<gt>{template}> line
1350 Fetch all book objects and pass to books/list.tt2 in stash to be displayed
1355 # Retrieve the usual Perl OO '$self' for this object. $c is the Catalyst
1356 # 'Context' that's used to 'glue together' the various components
1357 # that make up the application
1358 my ($self, $c) = @_;
1360 # Retrieve all of the book records as book model objects and store in the
1361 # stash where they can be accessed by the TT template
1362 $c->stash->{books} = [$c->model('DB::Books')->all];
1364 # Set the TT template to use. You will almost always want to do this
1365 # in your action methods (actions methods respond to user input in
1366 # your controllers).
1367 #$c->stash->{template} = 'books/list.tt2';
1371 You should now be able to restart the development server as per the
1372 previous section and access the L<http://localhost:3000/books/list>
1375 B<NOTE:> Please note that if you use the default template technique,
1376 you will B<not> be able to use either the C<$c-E<gt>forward> or
1377 the C<$c-E<gt>detach> mechanisms (these are discussed in Part 2 and
1378 Part 9 of the Tutorial).
1381 =head2 Return To A Manually-Specified Template
1383 In order to be able to use C<$c-E<gt>forward> and C<$c-E<gt>detach>
1384 later in the tutorial, you should remove the comment from the
1385 statement in C<sub list> in C<lib/MyApp/Controller/Books.pm>:
1387 $c->stash->{template} = 'books/list.tt2';
1389 Then delete the C<TEMPLATE_EXTENSION> line in
1390 C<lib/MyApp/View/TT.pm>.
1392 You should then be able to restart the development server and
1393 access L<http://localhost:3000/books/list> in the same manner as
1394 with earlier sections.
1399 Kennedy Clark, C<hkclark@gmail.com>
1401 Please report any errors, issues or suggestions to the author. The
1402 most recent version of the Catalyst Tutorial can be found at
1403 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.70/trunk/lib/Catalyst/Manual/Tutorial/>.
1405 Copyright 2006-2008, Kennedy Clark, under Creative Commons License
1406 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).