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
262 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
263 cd MyApp_Chapter8/MyApp
264 CATALYST_DEBUG=0 prove -wl t
270 =head1 VERSIONS AND CONVENTIONS USED IN THIS TUTORIAL
272 This tutorial was built using the following resources. Please note that
273 you may need to make adjustments for different environments and
274 versions (note that trailing zeros in version numbers are not
275 significant and may get dropped with techniques for viewing them;
276 for example, Catalyst v5.80020 might show up as 5.8002):
286 Catalyst v5.80020 (note: may show up as '5.8002' without the trailing zero)
290 Catalyst::Devel v1.26
298 Catalyst::Model::DBIC::Schema v0.40
302 Template Toolkit v2.20
309 The plugins used in this tutorial all have sufficiently stable APIs that
310 you shouldn't need to worry about versions. However, there could be
311 cases where the tutorial is affected by what version of plugins you
312 use. This tutorial has been tested against the following set of plugins:
318 Catalyst::Plugin::Authentication -- v0.10016
322 Catalyst::Plugin::Authorization::Roles -- v0.08
326 Catalyst::Plugin::ConfigLoader -- v0.27
330 Catalyst::Plugin::Session -- v0.29
334 Catalyst::Plugin::Session::State::Cookie -- v0.17
338 Catalyst::Plugin::Session::Store::FastMmap -- v0.13
342 Catalyst::Plugin::StackTrace -- v0.11
346 Catalyst::Plugin::Static::Simple -- v0.29
352 HTML::FormFu -- v0.06001
356 B<NOTE:> You can check the versions you have installed with the
359 perl -M<_mod_name_> -e '"print $<_mod_name_>::VERSION\n"'
363 perl -MCatalyst -e 'print "$Catalyst::VERSION\n";'
367 perl -MCatalyst::Devel -e 'print "$Catalyst::Devel::VERSION\n";'
371 This tutorial will assume that the web browser is located on the same
372 system where the Catalyst development server is running, and
373 therefore use a URL of C<http://localhost:3000> (the Catalyst
374 development server defaults to port 3000). If you are running Perl on
375 a different box than where your web browser is located (or using a
376 different port number via the C<-p> I<port_number> option to the
377 development server), then you will need to update the URL you use
380 Please Note: Depending on the web browser you are using, you might
381 need to hit C<Shift+Reload> or C<Ctrl+Reload> to pull a fresh page
382 when testing your application at various points (see
383 L<http://en.wikipedia.org/wiki/Bypass_your_cache> for a comprehensive
384 list of options for each browser). Also, the C<-k> keepalive option
385 to the development server can be necessary with some browsers
386 (especially Internet Explorer).
391 =head1 CATALYST INSTALLATION
393 Although Catalyst installation has been a challenge in the past, the
394 good news is that there are a growing number of options to eliminate
395 (or at least dramatically simplify) this concern. Although a
396 compelling strength of Catalyst is that it makes use of many of the
397 modules in the vast repository that is CPAN, this can complicate the
398 installation process if you approach it in the wrong way. Consider
399 the following suggestions on the most common ways to get started with
400 a Catalyst development environment:
408 The Debian 5 live CD represents a great way for newcomers to
409 experiment with Catalyst. As a "live CD," you can simple boot from
410 the CD, run a few commands, and in a matter of minutes you should have
411 a fully function environment in which do this tutorial. B<The tutorial
412 was fully tested to work under Debian 5. Although it SHOULD work
413 under any Catalyst installation method you might choose, it can be
414 hard to guarantee this.>
420 Download one of the ISO files from
421 L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-cd/>
422 (the current version at the time this was written was 5.0.3).
423 You can pick any one of the live CD variations will work, but
424 you may wish to consider the following points:
430 "C<debian-live-503-i386-rescue.iso>" is probably the best all-around
431 option for most people because it includes many extra tools such as
432 the GCC compiler, therefore saving RAM (every package you need to
433 install when running from live CD consumes memory because RAM disk is
434 being used in lieu of real disk space). When initially booting under
435 this image, you may see some cryptic warning messages having to do
436 with various diagnostic tools it tries to load or enable, but you
437 should be able to safely ignore these.
441 "C<debian-live-503-i386-standard.iso>" is a great option because of
442 its compact size, but you will probably need approximately 1 GB of RAM
443 in the computer where you will run the tutorial. Because the
444 "standard" live CD comes with with a minimal set of tools, we will
445 have to install extra packages (such as the GCC compiler), all of
446 which will require RAM when running from a live CD.
450 The other ISO images include different flavors of X-Windows desktop
451 managers. You can select one of these if you don't mind the larger
452 download size and prefer a graphical environment. Be aware that these
453 disks do not come with the extra tools found on the "rescue" image, so
454 you will need adequate RAM to be able to install them just as you
455 would under the "standard" image. B<Use one of the "graphical" ISO
456 images if you want a graphical web browser on the same machine as
457 where you will run the tutorial.> (If you are using one of the non-
458 graphical images discussed above, you can still use a graphical web
459 browser from another machine and point it to your Catalyst development
470 Select "C<Live>" from the initial boot menu.
474 Once the system has booted to a "C<user@debian:~$>" prompt, first
475 install the Subversion client in case you want to check out the
476 completed chapter example code:
478 sudo aptitude -y install subversion
480 If you want to be able to remotely SSH to this system, set a
486 Then enter the following command to add the more current "unstable"
487 package repository so we get the latest versions of Catalyst and
490 sudo vi /etc/apt/sources.list
492 Add the following line to the bottom of this file:
494 deb http://ftp.us.debian.org/debian/ unstable main
496 If you are not familiar with VI, you can move to the bottom of this
497 file and press the "o" key to insert a new line and type the line
498 above. Then press the "Esc" key followed by a colon (":"), the
499 letters "wq" and then the "Enter" key. The rest of the tutorial will
500 assume that you know how to use some editor that is available from the
501 Linux command-line environment.
508 sudo aptitude -y install sqlite3 libdbd-sqlite3-perl libcatalyst-perl \
509 libcatalyst-modules-perl libdbix-class-timestamp-perl \
510 libdatetime-format-sqlite-perl libconfig-general-perl \
511 libhtml-formfu-model-dbic-perl libterm-readline-perl-perl \
512 libdbix-class-encodedcolumn-perl libperl6-junction-perl
514 Let it install (normally about a 30 to 90-second operaton) and you are
515 done. (Note the '\' above. Depending on your environment, you might
516 be able to cut and paste the text as shown or need to remove the '\'
517 characters to that the command is all on a single line.)
519 If you are using an image other than the "rescue" ISO, you will also need
520 to run the following command to install additional packages:
522 sudo aptitude -y install gcc make libc6-dev
524 If you are running from the Live CD, you probably also want to free up
525 some RAM disk space with the following:
529 NOTE: While the instructions above mention the Live CD because that
530 makes it easy for people new to Linux, you can obviously pick a
531 different Debian ISO image and install it to your hard drive.
532 Although there are many different ways to download and install Debian,
533 the "netinst" ISO image (such as "C<debian-500-i386-netinst.iso>"
534 represents a great option because it keeps your initial download small
535 (but still let's you install anything you want "over the network").
537 Here are some tips if you are running from a live CD and are running
538 out of disk space (which really means you are running out of RAM):
544 Always run "C<aptitude clean>" after you install new packages to
545 delete the original .deb files (the files installed B<by> the .deb
546 package B<will> remain available, just the .deb package itself is
551 If you are installing modules from CPAN, you can free up some space
552 with "C<rm -rf /root/.cpan/*>" (change "/root/" in the previous
553 command to match your home directory or the location where CPAN
554 has been configured to perform build operations).
558 If necessary, you can remove the cached package information with the
559 command "C<rm -f /var/lib/apt/lists/*>". You can later pull this
560 information again via the command "C<aptitude update>".
564 You can save a small amount of space by commenting out the lines in
565 C</etc/apt/sources.list> that reference "deb-src" and
566 "security.debian.org". If you have already done an "C<aptitude
567 update>" with these repositories enabled, you can use the tip in the
568 previous bullet to free the space up (and then do another "C<aptitude
573 Although you can free up space by removing packages you installed
574 since you last booted (check out "C<aptitude remove _pkg_name>"),
575 don't bother trying to remove packages already available at the time
576 of boot. Instead of freeing up space, it will actual I<consume> some
577 space. (The live CD uses these "burn in" packages right from the CD
578 disk vs. first loading them on the virtual RAM disk. However, if you
579 remove them, the system has to update various files, something that
580 I<does> consume some space on the virtual RAM disk.)
590 Ubuntu is an extremely popular offshoot of Debian. It provides
591 cutting edge versions of many common tools, application and libraries
592 in an easy-to-run live CD configuration (and because a single download
593 option can be used for both live CD and install-to-disk usage, it
594 keeps your download options nice and simple). As with Debian 5, you
595 should be able to generate a fully function Catalyst environment in a
596 matter of minutes. Here are quick instructions on how to use Ubuntu
597 to prepare for the tutorial:
603 Download the Ubuntu Desktop edition and boot from the CD and/or image
604 file, select your language, and then "Try Ubuntu without any changes
609 Open a terminal session (click "Applications" in the upper-left
610 corner, then "Accessories," then "Terminal").
614 Add the 'universe' repositories:
616 sudo gedit /etc/apt/sources.list
618 And remove the comments from the lines under the comments about the
619 'universe' repositories.
626 sudo aptitude install libdbd-sqlite3-perl libcatalyst-perl libcatalyst-modules-perl libconfig-general-perl
628 Accept all of the dependencies. Done.
630 If you are running from the Live CD, you probably also want to free up
631 some disk space with the following:
635 NOTE: While the instructions above mention the live CD because that
636 makes it easy for people new to Linux, you can obviously also use one
637 of the options to install Ubuntu on your drive.
643 Matt Trout's C<cat-install>
645 Available at L<http://www.shadowcat.co.uk/static/cat-install>,
646 C<cat-install> can be a fairly painless way to get Catalyst up and
647 running. Just download the script from the link above and type C<perl
648 cat-install>. Depending on the speed of your Internet connection and
649 your computer, it will probably take 30 to 60 minutes to install because
650 it downloads, makes, compiles, and tests every module. But this is an
651 excellent way to automate the installation of all the latest modules
652 used by Catalyst from CPAN.
665 The 2008 Advent Day 4 entry has more information on using OpenBSD
666 packages to quickly build a system:
667 L<http://www.catalystframework.org/calendar/2008/4>.
671 NetBSD Package Collection on Solaris
673 The 2008 Advent Day 15 entry has more information on using C<pkgsrc> and
674 NetBSD packages on Solaris:
675 L<http://www.catalystframework.org/calendar/2008/15>.
681 You can get more information at
682 L<http://www.catalystframework.org/calendar/2008/7>
683 or L<Perl::Dist::CatInABox|Perl::Dist::CatInABox>.
687 Frank Speiser's Amazon EC2 Catalyst SDK
689 There are currently two flavors of publicly available Amazon Machine
690 Images (AMI) that include all the elements you'd need to begin
691 developing in a fully functional Catalyst environment within minutes.
692 See L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>
699 For additional information and recommendations on Catalyst installation,
701 L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>.
706 This tutorial will primarily focus on SQLite because of its simplicity
707 of installation and use; however, modifications in the script required
708 to support MySQL and PostgreSQL will be presented in Appendix.
710 B<Note:> One of the advantages of the MVC design patterns is that
711 applications become much more database independent. As such, you will
712 notice that only the C<.sql> files used to initialize the database
713 change between database systems: the Catalyst code generally remains the
717 =head1 WHERE TO GET WORKING CODE
719 Each chapter of the tutorial has complete code available as a tarball in
720 the main Catalyst Subversion repository (see the note at the beginning
721 of each part for the appropriate svn command to use).
723 B<NOTE:> You can run the test cases for the final code through Chapter 8
724 with the following commands:
726 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
727 cd MyApp_Chapter8/MyApp
728 CATALYST_DEBUG=0 prove -wl t
730 If you wish to include the L<HTML::FormFu|HTML::FormFu> section in your tests,
731 substitute C<MyApp_Chapter9_FormFu> for C<MyApp_Chapter8> in the URL
732 above (don't forget to "cd" out of the Ch8 directory if you ran the code above).
734 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter9_FormFu
735 cd MyApp_Chapter9_FormFu/MyApp
736 CATALYST_DEBUG=0 prove -wl t
738 You can also fire up the application under the development server that is conveniently
739 built in to Catalyst. Just issue this command from the C<MyApp> directory where you
740 ran the test suite above:
742 script/myapp_server.pl
744 And the application will start. You can try out the application by
745 pulling up C<http://localhost:3000> in your web browser (as mentioned
746 earlier, change C<localhost> to a different IP address or DNS name if
747 you are running your web browser and your Catalyst development on
748 different boxes). We will obviously see more about how to use the
749 application as we go through the remaining chapters of the tutorial, but
750 for now you can log in using the username "test01" and a password of
756 Kennedy Clark, C<hkclark@gmail.com>
758 Please report any errors, issues or suggestions to the author. The
759 most recent version of the Catalyst Tutorial can be found at
760 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
762 Copyright 2006-2008, Kennedy Clark, under Creative Commons License
763 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).