3 Catalyst::Manual::Tutorial::01_Intro - Catalyst Tutorial - Chapter 1: Introduction
8 This is B<Chapter 1 of 10> for the Catalyst tutorial.
10 L<Tutorial Overview|Catalyst::Manual::Tutorial>
20 L<Catalyst Basics|Catalyst::Manual::Tutorial::02_CatalystBasics>
24 L<More Catalyst Basics|Catalyst::Manual::Tutorial::03_MoreCatalystBasics>
28 L<Basic CRUD|Catalyst::Manual::Tutorial::04_BasicCRUD>
32 L<Authentication|Catalyst::Manual::Tutorial::05_Authentication>
36 L<Authorization|Catalyst::Manual::Tutorial::06_Authorization>
40 L<Debugging|Catalyst::Manual::Tutorial::07_Debugging>
44 L<Testing|Catalyst::Manual::Tutorial::08_Testing>
48 L<Advanced CRUD|Catalyst::Manual::Tutorial::09_AdvancedCRUD>
52 L<Appendices|Catalyst::Manual::Tutorial::10_Appendices>
59 This tutorial provides a multi-part introduction to the Catalyst web
60 framework. It seeks to provide a rapid overview of many of its most
61 commonly used features. The focus is on the real-world best practices
62 required in the construction of nearly all Catalyst applications.
64 Although the primary target of the tutorial is users new to the Catalyst
65 framework, experienced users may wish to review specific sections (for
66 example, how to use DBIC for their model classes, how to add
67 authentication and authorization to an existing application, or form
70 You can obtain the code for all the tutorial examples from the
71 catalyst subversion repository by issuing the command:
73 svn co http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial/ CatalystTutorial
75 This will download the most recent code for each chapter of the
76 tutorial into the CatalystTutorial directory on your machine.
78 B<These reference implementations are provided so that when you follow
79 the tutorial, you can use the code from the subversion repository to
80 ensure that your system is set up correctly, and that you have not
81 inadvertently made any typographic errors, or accidentally skipped
82 part of the tutorial.>
84 B<NOTE: You can use any Perl-supported OS and environment to run
85 Catalyst.> It should make little or no difference to Catalyst's
86 operation, B<but this tutorial has been written using the Debian 5
87 live CD> because that represents a quick and easy way for most people to
88 try out Catalyst with virtually zero setup time and hassles. Also,
89 the tutorial has been tested to work correctly with the versions of
90 Catalyst and all the supporting modules in Debian 5 (see "VERSIONS
91 AND CONVENTIONS USED IN THIS TUTORIAL" below for the specific versions
92 for some of the key modules), so B<if you think you might be running
93 into an issue related to versions> (for example, a module changed its
94 behavior in a newer version or a bug was introduced), B<it might be
95 worth giving Debian 5 a try>.
97 If you plan to follow along with Debian 5, you can jump down to the
98 "Debian" section under L</"CATALYST INSTALLATION"> below and it will walk you
99 though the setup of a fully functional Catalyst environment. If you
100 would prefer to install directly from CPAN, you can download the example
101 program and all the necessary dependencies to your local machine by
102 installing the C<Task::Catalyst::Tutorial> distribution:
104 cpan Task::Catalyst::Tutorial
106 This will also test to make sure the dependencies are working. If you
107 have trouble installing these, please ask for help on the #catalyst
108 IRC channel, or the Catalyst mailing list.
110 Subjects covered by the tutorial include:
116 A simple application that lists and adds books.
120 The use of L<DBIx::Class|DBIx::Class> (DBIC) for the model (including
121 some of the more advanced techniques you will probably want to use in
126 How to write CRUD (Create, Read, Update, and Delete) operations in
131 Authentication ("auth").
135 Role-based authorization ("authz").
139 Attempts to provide an example showing current (5.8XXX) Catalyst
140 practices. For example, the use of
141 L<Catalyst::Action::RenderView|Catalyst::Action::RenderView>,
142 DBIC, L<Catalyst::Plugin::ConfigLoader|Catalyst::Plugin::ConfigLoader>
143 with C<myapp.conf>, the use of C<lib/MyApp/Controller/Root.pm>
144 vs. C<lib/MyApp.pm>, etc.
148 The use of Template Toolkit (TT).
152 Useful techniques for troubleshooting and debugging Catalyst
157 The use of SQLite as a database (with code also provided for MySQL and
158 PostgreSQL). (Note: Because we make use of the DBIx::Class Object
159 Relational Mapping [ORM] layer, out our application will be database
160 agnostic and can easily be used by any of the databases supported
165 The use of L<HTML::FormFu|HTML::FormFu> or L<HTML::FormHandler|HTML::FormHandler>
166 for automated form processing and validation.
170 This tutorial makes the learning process its main priority. For
171 example, the level of comments in the code found here would likely be
172 considered excessive in a "normal project." Because of their contextual
173 value, this tutorial will generally favor inline comments over a
174 separate discussion in the text. It also deliberately tries to
175 demonstrate multiple approaches to various features (in general, you
176 should try to be as consistent as possible with your own production
179 Furthermore, this tutorial tries to minimize the number of controllers,
180 models, TT templates, and database tables. Although this does result in
181 things being a bit contrived at times, the concepts should be applicable
182 to more complex environments. More complete and complicated example
183 applications can be found in the C<examples> area of the Catalyst
184 Subversion repository at
185 L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/>.
188 =head1 VERSIONS AND CONVENTIONS USED IN THIS TUTORIAL
190 This tutorial was built using the following resources. Please note that
191 you may need to make adjustments for different environments and
192 versions (note that trailing zeros in version numbers are not
193 significant and may get dropped with techniques for viewing them;
194 for example, Catalyst v5.80020 might show up as 5.8002):
204 Catalyst v5.80020 (note: may show up as '5.8002' without the trailing zero)
208 Catalyst::Devel v1.26
216 Template Toolkit v2.20
222 The plugins used in this tutorial all have sufficiently stable APIs that
223 you shouldn't need to worry about versions. However, there could be
224 cases where the tutorial is affected by what version of plugins you
225 use. This tutorial has been tested against the following set of plugins:
231 Catalyst::Plugin::Authentication -- v0.10016
235 Catalyst::Plugin::Authorization::Roles -- v0.08
239 Catalyst::Plugin::ConfigLoader -- v0.27
243 Catalyst::Plugin::Session -- v0.29
247 Catalyst::Plugin::Session::State::Cookie -- v0.17
251 Catalyst::Plugin::Session::Store::FastMmap -- v0.13
255 Catalyst::Plugin::StackTrace -- v0.11
259 Catalyst::Plugin::Static::Simple -- v0.28
265 B<NOTE:> You can check the versions you have installed with the
268 perl -M<_mod_name_> -e '"print $<_mod_name_>::VERSION\n"'
272 perl -MCatalyst -e 'print "$Catalyst::VERSION\n";'
276 perl -MCatalyst::Devel -e 'print "$Catalyst::Devel::VERSION\n";'
280 This tutorial will assume that the web browser is located on the same
281 system where the Catalyst development server is running, and
282 therefore use a URL of C<http://localhost:3000> (the Catalyst
283 development server defaults to port 3000). If you are running Perl on
284 a different box than where your web browser is located (or using a
285 different port number via the C<-p> I<port_number> option to the
286 development server), then you will need to update the URL you use
289 Please Note: Depending on the web browser you are using, you might
290 need to hit C<Shift+Reload> or C<Ctrl+Reload> to pull a fresh page
291 when testing your application at various points (see
292 L<http://en.wikipedia.org/wiki/Bypass_your_cache> for a comprehensive
293 list of options for each browser). Also, the C<-k> keepalive option
294 to the development server can be necessary with some browsers
295 (especially Internet Explorer).
300 =head1 CATALYST INSTALLATION
302 Although Catalyst installation has been a challenge in the past, the
303 good news is that there are a growing number of options to eliminate
304 (or at least dramatically simplify) this concern. Although a
305 compelling strength of Catalyst is that it makes use of many of the
306 modules in the vast repository that is CPAN, this can complicate the
307 installation process if you approach it in the wrong way. Consider
308 the following suggestions on the most common ways to get started with
309 a Catalyst development environment:
317 The Debian 5 live CD represents a great way for newcomers to
318 experiment with Catalyst. As a "live CD," you can simple boot from
319 the CD, run a few commands, and in a matter of minutes you should have
320 a fully function environment in which do this tutorial. B<The tutorial
321 was fully tested to work under Debian 5. Although it SHOULD work
322 under any Catalyst installation method you might choose, it can be
323 hard to guarantee this.>
329 Download one of the ISO files from
330 L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-cd/>
331 (the current version at the time this was written was 5.0.3).
332 You can pick any one of the live CD variations will work, but
333 you may wish to consider the following points:
339 "C<debian-live-503-i386-rescue.iso>" is probably the best all-around
340 option for most people because it includes many extra tools such as
341 the GCC compiler, therefore saving RAM (every package you need to
342 install when running from live CD consumes memory because RAM disk is
343 being used in lieu of real disk space). When initially booting under
344 this image, you may see some cryptic warning messages having to do
345 with various diagnostic tools it tries to load or enable, but you
346 should be able to safely ignore these.
350 "C<debian-live-503-i386-standard.iso>" is a great option because of
351 its compact size, but you will probably need approximately 1 GB of RAM
352 in the computer where you will run the tutorial. Because the
353 "standard" live CD comes with with a minimal set of tools, we will
354 have to install extra packages (such as the GCC compiler), all of
355 which will require RAM when running from a live CD.
359 The other ISO images include different flavors of X-Windows desktop
360 managers. You can select one of these if you don't mind the larger
361 download size and prefer a graphical environment. Be aware that these
362 disks do not come with the extra tools found on the "rescue" image, so
363 you will need adequate RAM to be able to install them just as you
364 would under the "standard" image. B<Use one of the "graphical" ISO
365 images if you want a graphical web browser on the same machine as
366 where you will run the tutorial.> (If you are using one of the non-
367 graphical images discussed above, you can still use a graphical web
368 browser from another machine and point it to your Catalyst development
379 Select "C<Live>" from the initial boot menu.
383 Once the system has booted to a "C<user@debian:~$>" prompt, first
384 install the Subversion client in case you want to check out the
385 completed chapter example code:
387 sudo aptitude -y install subversion
389 Then enter the following command to add the more current "unstable"
390 package repository so we get the latest versions of Catalyst and
393 sudo vi /etc/apt/sources.list
395 Add the following line to the bottom of this file:
397 deb http://ftp.us.debian.org/debian/ unstable main
399 If you are not familiar with VI, you can move to the bottom of this
400 file and press the "o" key to insert a new line and type the line
401 above. Then press the "Esc" key followed by a colon (":"), the
402 letters "wq" and then the "Enter" key. The rest of the tutorial will
403 assume that you know how to use some editor that is available from the
404 Linux command-line environment.
411 sudo aptitude -y install sqlite3 libdbd-sqlite3-perl libcatalyst-perl \
412 libcatalyst-modules-perl libdbix-class-timestamp-perl \
413 libdatetime-format-sqlite-perl libconfig-general-perl \
414 libhtml-formfu-model-dbic-perl libterm-readline-perl-perl \
415 libdbix-class-encodedcolumn-perl
417 Let it install (normally about a 30 to 90-second operaton) and you are
418 done. (Note the '\' above. Depending on your environment, you might
419 be able to cut and paste the text as shown or need to remove the '\'
420 characters to that the command is all on a single line.)
422 If you are using an image other than the "rescue" ISO, you will also need
423 to run the following command to install additional packages:
425 sudo aptitude -y install gcc make libc6-dev
427 If you are running from the Live CD, you probably also want to free up
428 some RAM disk space with the following:
432 NOTE: While the instructions above mention the Live CD because that
433 makes it easy for people new to Linux, you can obviously pick a
434 different Debian ISO image and install it to your hard drive.
435 Although there are many different ways to download and install Debian,
436 the "netinst" ISO image (such as "C<debian-500-i386-netinst.iso>"
437 represents a great option because it keeps your initial download small
438 (but still let's you install anything you want "over the network").
440 Here are some tips if you are running from a live CD and are running
441 out of disk space (which really means you are running out of RAM):
447 Always run "C<aptitude clean>" after you install new packages to
448 delete the original .deb files (the files installed B<by> the .deb
449 package B<will> remain available, just the .deb package itself is
454 If you are installing modules from CPAN, you can free up some space
455 with "C<rm -rf /root/.cpan/*>" (change "/root/" in the previous
456 command to match your home directory or the location where CPAN
457 has been configured to perform build operations).
461 If necessary, you can remove the cached package information with the
462 command "C<rm -f /var/lib/apt/lists/*>". You can later pull this
463 information again via the command "C<aptitude update>".
467 You can save a small amount of space by commenting out the lines in
468 C</etc/apt/sources.list> that reference "deb-src" and
469 "security.debian.org". If you have already done an "C<aptitude
470 update>" with these repositories enabled, you can use the tip in the
471 previous bullet to free the space up (and then do another "C<aptitude
476 Although you can free up space by removing packages you installed
477 since you last booted (check out "C<aptitude remove _pkg_name>"),
478 don't bother trying to remove packages already available at the time
479 of boot. Instead of freeing up space, it will actual I<consume> some
480 space. (The live CD uses these "burn in" packages right from the CD
481 disk vs. first loading them on the virtual RAM disk. However, if you
482 remove them, the system has to update various files, something that
483 I<does> consume some space on the virtual RAM disk.)
493 Ubuntu is an extremely popular offshoot of Debian. It provides
494 cutting edge versions of many common tools, application and libraries
495 in an easy-to-run live CD configuration (and because a single download
496 option can be used for both live CD and install-to-disk usage, it
497 keeps your download options nice and simple). As with Debian 5, you
498 should be able to generate a fully function Catalyst environment in a
499 matter of minutes. Here are quick instructions on how to use Ubuntu
500 to prepare for the tutorial:
506 Download the Ubuntu Desktop edition and boot from the CD and/or image
507 file, select your language, and then "Try Ubuntu without any changes
512 Open a terminal session (click "Applications" in the upper-left
513 corner, then "Accessories," then "Terminal").
517 Add the 'universe' repositories:
519 sudo gedit /etc/apt/sources.list
521 And remove the comments from the lines under the comments about the
522 'universe' repositories.
529 sudo aptitude install libdbd-sqlite3-perl libcatalyst-perl libcatalyst-modules-perl libconfig-general-perl
531 Accept all of the dependencies. Done.
533 If you are running from the Live CD, you probably also want to free up
534 some disk space with the following:
538 NOTE: While the instructions above mention the live CD because that
539 makes it easy for people new to Linux, you can obviously also use one
540 of the options to install Ubuntu on your drive.
546 Matt Trout's C<cat-install>
548 Available at L<http://www.shadowcat.co.uk/static/cat-install>,
549 C<cat-install> can be a fairly painless way to get Catalyst up and
550 running. Just download the script from the link above and type C<perl
551 cat-install>. Depending on the speed of your Internet connection and
552 your computer, it will probably take 30 to 60 minutes to install because
553 it downloads, makes, compiles, and tests every module. But this is an
554 excellent way to automate the installation of all the latest modules
555 used by Catalyst from CPAN.
568 The 2008 Advent Day 4 entry has more information on using OpenBSD
569 packages to quickly build a system:
570 L<http://www.catalystframework.org/calendar/2008/4>.
574 NetBSD Package Collection on Solaris
576 The 2008 Advent Day 15 entry has more information on using C<pkgsrc> and
577 NetBSD packages on Solaris:
578 L<http://www.catalystframework.org/calendar/2008/15>.
584 You can get more information at
585 L<http://www.catalystframework.org/calendar/2008/7>
586 or L<Perl::Dist::CatInABox|Perl::Dist::CatInABox>.
590 Frank Speiser's Amazon EC2 Catalyst SDK
592 There are currently two flavors of publicly available Amazon Machine
593 Images (AMI) that include all the elements you'd need to begin
594 developing in a fully functional Catalyst environment within minutes.
595 See L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>
602 For additional information and recommendations on Catalyst installation,
604 L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>.
609 This tutorial will primarily focus on SQLite because of its simplicity
610 of installation and use; however, modifications in the script required
611 to support MySQL and PostgreSQL will be presented in Appendix.
613 B<Note:> One of the advantages of the MVC design patterns is that
614 applications become much more database independent. As such, you will
615 notice that only the C<.sql> files used to initialize the database
616 change between database systems: the Catalyst code generally remains the
620 =head1 WHERE TO GET WORKING CODE
622 Each chapter of the tutorial has complete code available as a tarball in
623 the main Catalyst Subversion repository (see the note at the beginning
624 of each part for the appropriate svn command to use).
626 B<NOTE:> You can run the test cases for the final code through Chapter 8
627 with the following commands:
629 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
630 cd MyApp_Chapter8/MyApp
631 CATALYST_DEBUG=0 prove -wl t
633 If you wish to include the L<HTML::FormFu|HTML::FormFu> section in your tests,
634 substitute C<MyApp_Chapter9_FormFu> for C<MyApp_Chapter8> in the URL
635 above (don't forget to "cd" out of the Ch8 directory if you ran the code above).
637 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter9_FormFu
638 cd MyApp_Chapter9_FormFu/MyApp
639 CATALYST_DEBUG=0 prove -wl t
641 You can also fire up the application under the development server that is conveniently
642 built in to Catalyst. Just issue this command from the C<MyApp> directory where you
643 ran the test suite above:
645 script/myapp_server.pl
647 And the application will start. You can try out the application by
648 pulling up C<http://localhost:3000> in your web browser (as mentioned
649 earlier, change C<localhost> to a different IP address or DNS name if
650 you are running your web browser and your Catalyst development on
651 different boxes). We will obviously see more about how to use the
652 application as we go through the remaining chapters of the tutorial, but
653 for now you can log in using the username "test01" and a password of
659 Kennedy Clark, C<hkclark@gmail.com>
661 Please report any errors, issues or suggestions to the author. The
662 most recent version of the Catalyst Tutorial can be found at
663 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
665 Copyright 2006-2008, Kennedy Clark, under Creative Commons License
666 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).