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, and/or
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 6 live
87 CD> because that represents a quick and easy way for most people to try
88 out Catalyst with virtually zero setup time and hassles. Also, the
89 tutorial has been tested to work correctly with the versions of Catalyst
90 and all the supporting modules in Debian 6 (see "VERSIONS AND
91 CONVENTIONS USED IN THIS TUTORIAL" below for the specific versions for
92 some of the key modules), so B<if you think you might be running into an
93 issue related to versions> (for example, a module changed its behavior
94 in a newer version or a bug was introduced), B<it might be worth giving
97 If you plan to follow along with Debian 6, you can jump down to the
98 "Debian" section under L</"CATALYST INSTALLATION"> below and it will
99 walk you though the setup of a fully functional Catalyst environment. If
100 you would prefer to install directly from CPAN, you can download the
101 example program and all the necessary dependencies to your local machine
102 by 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 (5.9) Catalyst
144 The use of Template Toolkit (TT).
148 Useful techniques for troubleshooting and debugging Catalyst
153 The use of SQLite as a database (with code also provided for MySQL and
154 PostgreSQL). (Note: Because we make use of the DBIx::Class Object
155 Relational Mapping [ORM] layer, out our application will be database
156 agnostic and can easily be used by any of the databases supported by
161 The use of L<HTML::FormFu|HTML::FormFu> or L<HTML::FormHandler|HTML::FormHandler>
162 for automated form processing and validation.
166 This tutorial makes the learning process its main priority. For
167 example, the level of comments in the code found here would likely be
168 considered excessive in a "normal project." Because of their contextual
169 value, this tutorial will generally favor inline comments over a
170 separate discussion in the text. It also deliberately tries to
171 demonstrate multiple approaches to various features (in general, you
172 should try to be as consistent as possible with your own production
175 Furthermore, this tutorial tries to minimize the number of controllers,
176 models, TT templates, and database tables. Although this does result in
177 things being a bit contrived at times, the concepts should be applicable
178 to more complex environments. More complete and complicated example
179 applications can be found in the C<examples> area of the Catalyst
180 Subversion repository at
181 L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/>.
182 ***Todo: update link above?
187 For those who want to get going quickly, here is a short "cookbook-style
188 recipe" to quickly get you up and running. Although there are many
189 different ways to get a Catalyst environment going, this tutorial has
190 been written with and tested against Debian 6 Live CD, using the steps
193 If you want, you can follow the directions in this section and then jump
194 right to L<Chapter 2|Catalyst::Manual::Tutorial::02_CatalystBasics> of
195 the tutorial. However, it would be a good idea to come back and read the
196 sections below the Quick Start when you have time. Or, continue reading
197 those other sections for suggestions if you do not wish to use the
205 Download the C<debian-live-6.0.1-i386-rescue.iso> image from
206 L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-hybrid/>.
210 Boot this disk, either in a physical machine, or possibly some sort
211 of virtual machine (using a VM can be a very handy way to practice).
215 Select "C<Live>" from the initial boot menu.
219 At the "C<user@debian:~$>" prompt, type:
221 sudo aptitude -y install subversion
225 If you want to be able to remotely SSH to this system, set a
233 Add the "unstable" Debian package repository:
235 sudo vi /etc/apt/sources.list
237 Add the following line to the bottom of this file:
239 deb http://ftp.us.debian.org/debian/ unstable main
243 Install Catalyst and related libraries:
246 sudo aptitude -y install sqlite3 libdbd-sqlite3-perl libcatalyst-perl \
247 libcatalyst-modules-perl libdbix-class-timestamp-perl \
248 libdatetime-format-sqlite-perl libconfig-general-perl \
249 libhtml-formfu-model-dbic-perl libterm-readline-perl-perl \
250 libdbix-class-encodedcolumn-perl libperl6-junction-perl \
260 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
261 cd MyApp_Chapter8/MyApp
262 CATALYST_DEBUG=0 prove -wl t
268 =head1 VERSIONS AND CONVENTIONS USED IN THIS TUTORIAL
270 This tutorial was built using the following resources. Please note that
271 you may need to make adjustments for different environments and
272 versions (note that trailing zeros in version numbers are not
273 significant and may get dropped with techniques for viewing them;
274 for example, Catalyst v5.80020 might show up as 5.8002):
284 Catalyst v5.80020 (note: may show up as '5.8002' without the trailing zero)
288 Catalyst::Devel v1.26
296 Catalyst::Model::DBIC::Schema v0.40
300 Template Toolkit v2.20
307 The plugins used in this tutorial all have sufficiently stable APIs that
308 you shouldn't need to worry about versions. However, there could be
309 cases where the tutorial is affected by what version of plugins you
310 use. This tutorial has been tested against the following set of plugins:
316 Catalyst::Plugin::Authentication -- v0.10016
320 Catalyst::Plugin::Authorization::Roles -- v0.08
324 Catalyst::Plugin::ConfigLoader -- v0.27
328 Catalyst::Plugin::Session -- v0.29
332 Catalyst::Plugin::Session::State::Cookie -- v0.17
336 Catalyst::Plugin::Session::Store::File -- v0.18
340 Catalyst::Plugin::StackTrace -- v0.11
344 Catalyst::Plugin::Static::Simple -- v0.29
350 HTML::FormFu -- v0.06001
354 B<NOTE:> You can check the versions you have installed with the
357 perl -M<_mod_name_> -e 'print "$<_mod_name_>::VERSION\n"'
361 perl -MCatalyst -e 'print "$Catalyst::VERSION\n";'
365 perl -MCatalyst::Devel -e 'print "$Catalyst::Devel::VERSION\n";'
369 This tutorial will assume that the web browser is located on the same
370 system where the Catalyst development server is running, and therefore
371 use a URL of C<http://localhost:3000> (the Catalyst development server
372 defaults to port 3000). If you are running Perl on a different box than
373 where your web browser is located (or using a different port number via
374 the C<-p> I<port_number> option to the development server), then you
375 will need to update the URL you use accordingly.
377 Please Note: Depending on the web browser you are using, you might need
378 to hit C<Shift+Reload> or C<Ctrl+Reload> to pull a fresh page when
379 testing your application at various points (see
380 L<http://en.wikipedia.org/wiki/Bypass_your_cache> for a comprehensive
381 list of options for each browser). Also, the C<-k> keepalive option to
382 the development server can be necessary with some browsers (especially
383 Internet Explorer). ***Todo: is this still true?
388 =head1 CATALYST INSTALLATION
390 Although Catalyst installation has been a challenge in the past, the
391 good news is that there are a growing number of options to eliminate (or
392 at least dramatically simplify) this concern. Although a compelling
393 strength of Catalyst is that it makes use of many of the modules in the
394 vast repository that is CPAN, this can complicate the installation
395 process if you approach it in the wrong way. Consider the following
396 suggestions on the most common ways to get started with a Catalyst
397 development environment:
405 The Debian 6 Live CD represents a great way for newcomers to experiment
406 with Catalyst. As a "live CD," you can simple boot from the CD, run a
407 few commands, and in a matter of minutes you should have a fully
408 function environment in which do this tutorial. B<The tutorial was fully
409 tested to work under Debian 6. Although it SHOULD work under any
410 Catalyst installation method you might choose, it can be hard to
417 Download one of the ISO files from
418 L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-hybrid/>
419 (the current version at the time this was written was 6.0.1). You can
420 pick any one of the live CD variations will work, but you may wish to
421 consider the following points:
427 "C<debian-live-6.0.1-i386-rescue.iso>" is probably the best all-around
428 option for most people because it includes many extra tools such as the
429 GCC compiler, therefore saving RAM (every package you need to install
430 when running from live CD consumes memory because RAM disk is being used
431 in lieu of real disk space). When initially booting under this image,
432 you may see some cryptic warning messages having to do with various
433 diagnostic tools it tries to load or enable, but you should be able to
438 "C<debian-live-6.0.1-i386-standard.iso>" is a great option because of
439 its compact size, but you will probably need approximately 1 GB of RAM
440 in the computer where you will run the tutorial. Because the "standard"
441 live CD comes with with a minimal set of tools, we will have to install
442 extra packages (such as the GCC compiler), all of which will require RAM
443 when running from a live CD.
447 The other ISO images include different flavors of X-Windows desktop
448 managers. You can select one of these if you don't mind the larger
449 download size and prefer a graphical environment. Be aware that these
450 disks do not come with the extra tools found on the "rescue" image, so
451 you will need adequate RAM to be able to install them just as you would
452 under the "standard" image. B<Use one of the "graphical" ISO images if
453 you want a graphical web browser on the same machine as where you will
454 run the tutorial.> (If you are using one of the non- graphical images
455 discussed above, you can still use a graphical web browser from another
456 machine and point it to your Catalyst development machine.)
466 Select "C<Live>" from the initial boot menu.
470 Once the system has booted to a "C<user@debian:~$>" prompt, first
471 install the Subversion client in case you want to check out the
472 completed chapter example code:
474 sudo aptitude -y install subversion
476 If you want to be able to remotely SSH to this system, set a
482 Then enter the following command to add the more current "unstable"
483 package repository so we get the latest versions of Catalyst and related
486 sudo vi /etc/apt/sources.list
488 Add the following line to the bottom of this file:
490 deb http://ftp.us.debian.org/debian/ unstable main
492 If you are not familiar with VI, you can move to the bottom of this file
493 and press the "o" key to insert a new line and type the line above.
494 Then press the "Esc" key followed by a colon (":"), the letters "wq" and
495 then the "Enter" key. The rest of the tutorial will assume that you
496 know how to use some editor that is available from the Linux
497 command-line environment.
504 sudo aptitude -y install sqlite3 libdbd-sqlite3-perl libcatalyst-perl \
505 libcatalyst-modules-perl libdbix-class-timestamp-perl \
506 libdatetime-format-sqlite-perl libconfig-general-perl \
507 libhtml-formfu-model-dbic-perl libterm-readline-perl-perl \
508 libdbix-class-encodedcolumn-perl libperl6-junction-perl \
511 Let it install (normally about a 30 to 90-second operaton) and you are
512 done. (Note the '\' above. Depending on your environment, you might
513 be able to cut and paste the text as shown or need to remove the '\'
514 characters to that the command is all on a single line.)
516 If you are using an image other than the "rescue" ISO, you will also need
517 to run the following command to install additional packages:
519 sudo aptitude -y install gcc make libc6-dev
521 If you are running from the Live CD, you probably also want to free up
522 some RAM disk space with the following:
526 NOTE: While the instructions above mention the Live CD because that
527 makes it easy for people new to Linux, you can obviously pick a
528 different Debian ISO image and install it to your hard drive. Although
529 there are many different ways to download and install Debian, the
530 "netinst" ISO image (such as "C<debian-500-i386-netinst.iso>" represents
531 a great option because it keeps your initial download small (but still
532 lets you install anything you want "over the network").
534 Here are some tips if you are running from a live CD and are running
535 out of disk space (which really means you are running out of RAM):
541 Always run "C<aptitude clean>" after you install new packages to delete
542 the original .deb files (the files installed B<by> the .deb package
543 B<will> remain available, just the .deb package itself is deleted).
547 If you are installing modules from CPAN, you can free up some space with
548 "C<rm -rf /root/.cpan/*>" (change "/root/" in the previous command to
549 match your home directory or the location where CPAN has been configured
550 to perform build operations).
554 If necessary, you can remove the cached package information with the
555 command "C<rm -f /var/lib/apt/lists/*>". You can later pull this
556 information again via the command "C<aptitude update>".
560 You can save a small amount of space by commenting out the lines in
561 C</etc/apt/sources.list> that reference "deb-src" and
562 "security.debian.org". If you have already done an "C<aptitude update>"
563 with these repositories enabled, you can use the tip in the previous
564 bullet to free the space up (and then do another "C<aptitude update>").
568 Although you can free up space by removing packages you installed since
569 you last booted (check out "C<aptitude remove _pkg_name>"), don't bother
570 trying to remove packages already available at the time of boot. Instead
571 of freeing up space, it will actual I<consume> some space. (The live CD
572 uses these "burn in" packages right from the CD disk vs. first loading
573 them on the virtual RAM disk. However, if you remove them, the system
574 has to update various files, something that I<does> consume some space
575 on the virtual RAM disk.)
585 Ubuntu is an extremely popular offshoot of Debian. It provides cutting
586 edge versions of many common tools, application and libraries in an
587 easy-to-run live CD configuration (and because a single download option
588 can be used for both live CD and install-to-disk usage, it keeps your
589 download options nice and simple). As with Debian 6, you should be able
590 to generate a fully function Catalyst environment in a matter of
591 minutes. Here are quick instructions on how to use Ubuntu to prepare
598 Download the Ubuntu Desktop edition and boot from the CD and/or image
599 file, select your language, and then "Try Ubuntu without any changes to
604 Open a terminal session (click "Applications" in the upper-left corner,
605 then "Accessories," then "Terminal").
609 Add the 'universe' repositories:
611 sudo gedit /etc/apt/sources.list
613 And remove the comments from the lines under the comments about the
614 'universe' repositories.
621 sudo aptitude install libdbd-sqlite3-perl libcatalyst-perl libcatalyst-modules-perl libconfig-general-perl
623 Accept all of the dependencies. Done.
625 If you are running from the Live CD, you probably also want to free up
626 some disk space with the following:
630 NOTE: While the instructions above mention the live CD because that
631 makes it easy for people new to Linux, you can obviously also use one of
632 the options to install Ubuntu on your drive.
638 Matt Trout's C<cat-install>
640 Available at L<http://www.shadowcat.co.uk/static/cat-install>,
641 C<cat-install> can be a fairly painless way to get Catalyst up and
642 running. Just download the script from the link above and type C<perl
643 cat-install>. Depending on the speed of your Internet connection and
644 your computer, it will probably take 30 to 60 minutes to install because
645 it downloads, makes, compiles, and tests every module. But this is an
646 excellent way to automate the installation of all the latest modules
647 used by Catalyst from CPAN.
660 The 2008 Advent Day 4 entry has more information on using OpenBSD
661 packages to quickly build a system:
662 L<http://www.catalystframework.org/calendar/2008/4>.
666 NetBSD Package Collection on Solaris
668 The 2008 Advent Day 15 entry has more information on using C<pkgsrc> and
669 NetBSD packages on Solaris:
670 L<http://www.catalystframework.org/calendar/2008/15>.
676 You can get more information at
677 L<http://www.catalystframework.org/calendar/2008/7> or
678 L<Perl::Dist::CatInABox|Perl::Dist::CatInABox>.
682 Frank Speiser's Amazon EC2 Catalyst SDK
684 There are currently two flavors of publicly available Amazon Machine
685 Images (AMI) that include all the elements you'd need to begin
686 developing in a fully functional Catalyst environment within minutes.
687 See L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>
694 For additional information and recommendations on Catalyst installation,
696 L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>.
701 This tutorial will primarily focus on SQLite because of its simplicity
702 of installation and use; however, modifications in the script required
703 to support MySQL and PostgreSQL will be presented in Appendix.
705 B<Note:> One of the advantages of the MVC design patterns is that
706 applications become much more database independent. As such, you will
707 notice that only the C<.sql> files used to initialize the database
708 change between database systems: the Catalyst code generally remains the
712 =head1 WHERE TO GET WORKING CODE
714 Each chapter of the tutorial has complete code available as a tarball in
715 the main Catalyst Subversion repository (see the note at the beginning
716 of each part for the appropriate svn command to use).
718 B<NOTE:> You can run the test cases for the final code through Chapter 8
719 with the following commands:
721 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
722 cd MyApp_Chapter8/MyApp
723 CATALYST_DEBUG=0 prove -wl t
725 If you wish to include the L<HTML::FormFu|HTML::FormFu> section in your tests,
726 substitute C<MyApp_Chapter9_FormFu> for C<MyApp_Chapter8> in the URL
727 above (don't forget to "cd" out of the Ch8 directory if you ran the code above).
729 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter9_FormFu
730 cd MyApp_Chapter9_FormFu/MyApp
731 CATALYST_DEBUG=0 prove -wl t
733 You can also fire up the application under the development server that is conveniently
734 built in to Catalyst. Just issue this command from the C<MyApp> directory where you
735 ran the test suite above:
737 script/myapp_server.pl
739 And the application will start. You can try out the application by
740 pulling up C<http://localhost:3000> in your web browser (as mentioned
741 earlier, change C<localhost> to a different IP address or DNS name if
742 you are running your web browser and your Catalyst development on
743 different boxes). We will obviously see more about how to use the
744 application as we go through the remaining chapters of the tutorial, but
745 for now you can log in using the username "test01" and a password of
751 Kennedy Clark, C<hkclark@gmail.com>
753 Please report any errors, issues or suggestions to the author. The
754 most recent version of the Catalyst Tutorial can be found at
755 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
757 Copyright 2006-2010, Kennedy Clark, under the
758 Creative Commons Attribution Share-Alike License Version 3.0
759 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).