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/>.
190 For those who want to get going quickly, here is a short "cookbook-style
191 recipe" to quickly get you up and running. Although there are many
192 different ways to get a Catalyst environment going, this tutorial has
193 been written with and tested against Debian 5 Live CD, using the steps
196 If you want, you can follow the directions in this section and then jump
197 right to L<Chapter 2|Catalyst::Manual::Tutorial::02_CatalystBasics> of
198 the tutorial. However, it would be a good idea to come back and read the
199 sections below the Quick Start when you have time. Or, continue reading
200 those other sections for suggestions if you do not wish to use the
208 Download the C<debian-live-503-i386-rescue.iso> image from
209 L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-cd/>.
213 Boot this disk, either in a physical machine, or possibly some sort
214 of virtual machine (can be a very handy way to practice).
218 Select "C<Live>" from the initial boot menu.
222 At the "C<user@debian:~$>" prompt, type:
224 sudo aptitude -y install subversion
228 If you want to be able to remotely SSH to this system, set a
236 Add the "unstable" Debian package repository:
238 sudo vi /etc/apt/sources.list
240 Add the following line to the bottom of this file:
242 deb http://ftp.us.debian.org/debian/ unstable main
246 Install Catalyst and related libraries:
249 sudo aptitude -y install sqlite3 libdbd-sqlite3-perl libcatalyst-perl \
250 libcatalyst-modules-perl libdbix-class-timestamp-perl \
251 libdatetime-format-sqlite-perl libconfig-general-perl \
252 libhtml-formfu-model-dbic-perl libterm-readline-perl-perl \
253 libdbix-class-encodedcolumn-perl libperl6-junction-perl \
263 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
264 cd MyApp_Chapter8/MyApp
265 CATALYST_DEBUG=0 prove -wl t
271 =head1 VERSIONS AND CONVENTIONS USED IN THIS TUTORIAL
273 This tutorial was built using the following resources. Please note that
274 you may need to make adjustments for different environments and
275 versions (note that trailing zeros in version numbers are not
276 significant and may get dropped with techniques for viewing them;
277 for example, Catalyst v5.80020 might show up as 5.8002):
287 Catalyst v5.80020 (note: may show up as '5.8002' without the trailing zero)
291 Catalyst::Devel v1.26
299 Catalyst::Model::DBIC::Schema v0.40
303 Template Toolkit v2.20
310 The plugins used in this tutorial all have sufficiently stable APIs that
311 you shouldn't need to worry about versions. However, there could be
312 cases where the tutorial is affected by what version of plugins you
313 use. This tutorial has been tested against the following set of plugins:
319 Catalyst::Plugin::Authentication -- v0.10016
323 Catalyst::Plugin::Authorization::Roles -- v0.08
327 Catalyst::Plugin::ConfigLoader -- v0.27
331 Catalyst::Plugin::Session -- v0.29
335 Catalyst::Plugin::Session::State::Cookie -- v0.17
339 Catalyst::Plugin::Session::Store::FastMmap -- v0.13
343 Catalyst::Plugin::StackTrace -- v0.11
347 Catalyst::Plugin::Static::Simple -- v0.29
353 HTML::FormFu -- v0.06001
357 B<NOTE:> You can check the versions you have installed with the
360 perl -M<_mod_name_> -e 'print "$<_mod_name_>::VERSION\n"'
364 perl -MCatalyst -e 'print "$Catalyst::VERSION\n";'
368 perl -MCatalyst::Devel -e 'print "$Catalyst::Devel::VERSION\n";'
372 This tutorial will assume that the web browser is located on the same
373 system where the Catalyst development server is running, and
374 therefore use a URL of C<http://localhost:3000> (the Catalyst
375 development server defaults to port 3000). If you are running Perl on
376 a different box than where your web browser is located (or using a
377 different port number via the C<-p> I<port_number> option to the
378 development server), then you will need to update the URL you use
381 Please Note: Depending on the web browser you are using, you might
382 need to hit C<Shift+Reload> or C<Ctrl+Reload> to pull a fresh page
383 when testing your application at various points (see
384 L<http://en.wikipedia.org/wiki/Bypass_your_cache> for a comprehensive
385 list of options for each browser). Also, the C<-k> keepalive option
386 to the development server can be necessary with some browsers
387 (especially Internet Explorer).
392 =head1 CATALYST INSTALLATION
394 Although Catalyst installation has been a challenge in the past, the
395 good news is that there are a growing number of options to eliminate
396 (or at least dramatically simplify) this concern. Although a
397 compelling strength of Catalyst is that it makes use of many of the
398 modules in the vast repository that is CPAN, this can complicate the
399 installation process if you approach it in the wrong way. Consider
400 the following suggestions on the most common ways to get started with
401 a Catalyst development environment:
409 The Debian 5 live CD represents a great way for newcomers to
410 experiment with Catalyst. As a "live CD," you can simple boot from
411 the CD, run a few commands, and in a matter of minutes you should have
412 a fully function environment in which do this tutorial. B<The tutorial
413 was fully tested to work under Debian 5. Although it SHOULD work
414 under any Catalyst installation method you might choose, it can be
415 hard to guarantee this.>
421 Download one of the ISO files from
422 L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-cd/>
423 (the current version at the time this was written was 5.0.3).
424 You can pick any one of the live CD variations will work, but
425 you may wish to consider the following points:
431 "C<debian-live-503-i386-rescue.iso>" is probably the best all-around
432 option for most people because it includes many extra tools such as
433 the GCC compiler, therefore saving RAM (every package you need to
434 install when running from live CD consumes memory because RAM disk is
435 being used in lieu of real disk space). When initially booting under
436 this image, you may see some cryptic warning messages having to do
437 with various diagnostic tools it tries to load or enable, but you
438 should be able to safely ignore these.
442 "C<debian-live-503-i386-standard.iso>" is a great option because of
443 its compact size, but you will probably need approximately 1 GB of RAM
444 in the computer where you will run the tutorial. Because the
445 "standard" live CD comes with with a minimal set of tools, we will
446 have to install extra packages (such as the GCC compiler), all of
447 which will require RAM when running from a live CD.
451 The other ISO images include different flavors of X-Windows desktop
452 managers. You can select one of these if you don't mind the larger
453 download size and prefer a graphical environment. Be aware that these
454 disks do not come with the extra tools found on the "rescue" image, so
455 you will need adequate RAM to be able to install them just as you
456 would under the "standard" image. B<Use one of the "graphical" ISO
457 images if you want a graphical web browser on the same machine as
458 where you will run the tutorial.> (If you are using one of the non-
459 graphical images discussed above, you can still use a graphical web
460 browser from another machine and point it to your Catalyst development
471 Select "C<Live>" from the initial boot menu.
475 Once the system has booted to a "C<user@debian:~$>" prompt, first
476 install the Subversion client in case you want to check out the
477 completed chapter example code:
479 sudo aptitude -y install subversion
481 If you want to be able to remotely SSH to this system, set a
487 Then enter the following command to add the more current "unstable"
488 package repository so we get the latest versions of Catalyst and
491 sudo vi /etc/apt/sources.list
493 Add the following line to the bottom of this file:
495 deb http://ftp.us.debian.org/debian/ unstable main
497 If you are not familiar with VI, you can move to the bottom of this
498 file and press the "o" key to insert a new line and type the line
499 above. Then press the "Esc" key followed by a colon (":"), the
500 letters "wq" and then the "Enter" key. The rest of the tutorial will
501 assume that you know how to use some editor that is available from the
502 Linux command-line environment.
509 sudo aptitude -y install sqlite3 libdbd-sqlite3-perl libcatalyst-perl \
510 libcatalyst-modules-perl libdbix-class-timestamp-perl \
511 libdatetime-format-sqlite-perl libconfig-general-perl \
512 libhtml-formfu-model-dbic-perl libterm-readline-perl-perl \
513 libdbix-class-encodedcolumn-perl libperl6-junction-perl \
516 Let it install (normally about a 30 to 90-second operaton) and you are
517 done. (Note the '\' above. Depending on your environment, you might
518 be able to cut and paste the text as shown or need to remove the '\'
519 characters to that the command is all on a single line.)
521 If you are using an image other than the "rescue" ISO, you will also need
522 to run the following command to install additional packages:
524 sudo aptitude -y install gcc make libc6-dev
526 If you are running from the Live CD, you probably also want to free up
527 some RAM disk space with the following:
531 NOTE: While the instructions above mention the Live CD because that
532 makes it easy for people new to Linux, you can obviously pick a
533 different Debian ISO image and install it to your hard drive.
534 Although there are many different ways to download and install Debian,
535 the "netinst" ISO image (such as "C<debian-500-i386-netinst.iso>"
536 represents a great option because it keeps your initial download small
537 (but still let's you install anything you want "over the network").
539 Here are some tips if you are running from a live CD and are running
540 out of disk space (which really means you are running out of RAM):
546 Always run "C<aptitude clean>" after you install new packages to
547 delete the original .deb files (the files installed B<by> the .deb
548 package B<will> remain available, just the .deb package itself is
553 If you are installing modules from CPAN, you can free up some space
554 with "C<rm -rf /root/.cpan/*>" (change "/root/" in the previous
555 command to match your home directory or the location where CPAN
556 has been configured to perform build operations).
560 If necessary, you can remove the cached package information with the
561 command "C<rm -f /var/lib/apt/lists/*>". You can later pull this
562 information again via the command "C<aptitude update>".
566 You can save a small amount of space by commenting out the lines in
567 C</etc/apt/sources.list> that reference "deb-src" and
568 "security.debian.org". If you have already done an "C<aptitude
569 update>" with these repositories enabled, you can use the tip in the
570 previous bullet to free the space up (and then do another "C<aptitude
575 Although you can free up space by removing packages you installed
576 since you last booted (check out "C<aptitude remove _pkg_name>"),
577 don't bother trying to remove packages already available at the time
578 of boot. Instead of freeing up space, it will actual I<consume> some
579 space. (The live CD uses these "burn in" packages right from the CD
580 disk vs. first loading them on the virtual RAM disk. However, if you
581 remove them, the system has to update various files, something that
582 I<does> consume some space on the virtual RAM disk.)
592 Ubuntu is an extremely popular offshoot of Debian. It provides
593 cutting edge versions of many common tools, application and libraries
594 in an easy-to-run live CD configuration (and because a single download
595 option can be used for both live CD and install-to-disk usage, it
596 keeps your download options nice and simple). As with Debian 5, you
597 should be able to generate a fully function Catalyst environment in a
598 matter of minutes. Here are quick instructions on how to use Ubuntu
599 to prepare for the tutorial:
605 Download the Ubuntu Desktop edition and boot from the CD and/or image
606 file, select your language, and then "Try Ubuntu without any changes
611 Open a terminal session (click "Applications" in the upper-left
612 corner, then "Accessories," then "Terminal").
616 Add the 'universe' repositories:
618 sudo gedit /etc/apt/sources.list
620 And remove the comments from the lines under the comments about the
621 'universe' repositories.
628 sudo aptitude install libdbd-sqlite3-perl libcatalyst-perl libcatalyst-modules-perl libconfig-general-perl
630 Accept all of the dependencies. Done.
632 If you are running from the Live CD, you probably also want to free up
633 some disk space with the following:
637 NOTE: While the instructions above mention the live CD because that
638 makes it easy for people new to Linux, you can obviously also use one
639 of the options to install Ubuntu on your drive.
645 Matt Trout's C<cat-install>
647 Available at L<http://www.shadowcat.co.uk/static/cat-install>,
648 C<cat-install> can be a fairly painless way to get Catalyst up and
649 running. Just download the script from the link above and type C<perl
650 cat-install>. Depending on the speed of your Internet connection and
651 your computer, it will probably take 30 to 60 minutes to install because
652 it downloads, makes, compiles, and tests every module. But this is an
653 excellent way to automate the installation of all the latest modules
654 used by Catalyst from CPAN.
667 The 2008 Advent Day 4 entry has more information on using OpenBSD
668 packages to quickly build a system:
669 L<http://www.catalystframework.org/calendar/2008/4>.
673 NetBSD Package Collection on Solaris
675 The 2008 Advent Day 15 entry has more information on using C<pkgsrc> and
676 NetBSD packages on Solaris:
677 L<http://www.catalystframework.org/calendar/2008/15>.
683 You can get more information at
684 L<http://www.catalystframework.org/calendar/2008/7>
685 or L<Perl::Dist::CatInABox|Perl::Dist::CatInABox>.
689 Frank Speiser's Amazon EC2 Catalyst SDK
691 There are currently two flavors of publicly available Amazon Machine
692 Images (AMI) that include all the elements you'd need to begin
693 developing in a fully functional Catalyst environment within minutes.
694 See L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>
701 For additional information and recommendations on Catalyst installation,
703 L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>.
708 This tutorial will primarily focus on SQLite because of its simplicity
709 of installation and use; however, modifications in the script required
710 to support MySQL and PostgreSQL will be presented in Appendix.
712 B<Note:> One of the advantages of the MVC design patterns is that
713 applications become much more database independent. As such, you will
714 notice that only the C<.sql> files used to initialize the database
715 change between database systems: the Catalyst code generally remains the
719 =head1 WHERE TO GET WORKING CODE
721 Each chapter of the tutorial has complete code available as a tarball in
722 the main Catalyst Subversion repository (see the note at the beginning
723 of each part for the appropriate svn command to use).
725 B<NOTE:> You can run the test cases for the final code through Chapter 8
726 with the following commands:
728 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
729 cd MyApp_Chapter8/MyApp
730 CATALYST_DEBUG=0 prove -wl t
732 If you wish to include the L<HTML::FormFu|HTML::FormFu> section in your tests,
733 substitute C<MyApp_Chapter9_FormFu> for C<MyApp_Chapter8> in the URL
734 above (don't forget to "cd" out of the Ch8 directory if you ran the code above).
736 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter9_FormFu
737 cd MyApp_Chapter9_FormFu/MyApp
738 CATALYST_DEBUG=0 prove -wl t
740 You can also fire up the application under the development server that is conveniently
741 built in to Catalyst. Just issue this command from the C<MyApp> directory where you
742 ran the test suite above:
744 script/myapp_server.pl
746 And the application will start. You can try out the application by
747 pulling up C<http://localhost:3000> in your web browser (as mentioned
748 earlier, change C<localhost> to a different IP address or DNS name if
749 you are running your web browser and your Catalyst development on
750 different boxes). We will obviously see more about how to use the
751 application as we go through the remaining chapters of the tutorial, but
752 for now you can log in using the username "test01" and a password of
758 Kennedy Clark, C<hkclark@gmail.com>
760 Please report any errors, issues or suggestions to the author. The
761 most recent version of the Catalyst Tutorial can be found at
762 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
764 Copyright 2006-2010, Kennedy Clark, under Creative Commons License
765 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).