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 tarball 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
206 Catalyst::Devel v1.21
214 Template Toolkit v2.20
220 The plugins used in this tutorial all have sufficiently stable APIs that
221 you shouldn't need to worry about versions. However, there could be
222 cases where the tutorial is affected by what version of plugins you
223 use. This tutorial has been tested against the following set of plugins:
229 Catalyst::Plugin::Authentication -- v0.10015
233 Catalyst::Plugin::Authorization::Roles -- v0.07
237 Catalyst::Plugin::ConfigLoader -- v0.27
241 Catalyst::Plugin::Session -- v0.29
245 Catalyst::Plugin::Session::State::Cookie -- v0.17
249 Catalyst::Plugin::Session::Store::FastMmap -- v0.13
253 Catalyst::Plugin::StackTrace -- v0.11
257 Catalyst::Plugin::Static::Simple -- v0.25
263 B<NOTE:> You can check the versions you have installed with the
266 perl -M<_mod_name_> -e '"print $<_mod_name_>::VERSION\n"'
270 perl -MCatalyst -e 'print "$Catalyst::VERSION\n";'
274 perl -MCatalyst::Devel -e 'print "$Catalyst::Devel::VERSION\n";'
278 This tutorial will assume that the web browser is located on the same
279 system where the Catalyst development server is running, and
280 therefore use a URL of C<http://localhost:3000> (the Catalyst
281 development server defaults to port 3000). If you are running Perl on
282 a different box than where your web browser is located (or using a
283 different port number via the C<-p> I<port_number> option to the
284 development server), then you will need to update the URL you use
287 Please Note: Depending on the web browser you are using, you might
288 need to hit C<Shift+Reload> or C<Ctrl+Reload> to pull a fresh page
289 when testing your application at various points (see
290 L<http://en.wikipedia.org/wiki/Bypass_your_cache> for a comprehensive
291 list of options for each browser). Also, the C<-k> keepalive option
292 to the development server can be necessary with some browsers
293 (especially Internet Explorer).
298 =head1 CATALYST INSTALLATION
300 Although Catalyst installation has been a challenge in the past, the
301 good news is that there are a growing number of options to eliminate
302 (or at least dramatically simplify) this concern. Although a
303 compelling strength of Catalyst is that it makes use of many of the
304 modules in the vast repository that is CPAN, this can complicate the
305 installation process if you approach it in the wrong way. Consider
306 the following suggestions on the most common ways to get started with
307 a Catalyst development environment:
315 The Debian 5 live CD represents a great way for newcomers to
316 experiment with Catalyst. As a "live CD," you can simple boot from
317 the CD, run a few commands, and in a matter of minutes you should have
318 a fully function environment in which do this tutorial. B<The tutorial
319 was fully tested to work under Debian 5. Although it SHOULD work
320 under any Catalyst installation method you might choose, it can be
321 hard to guarantee this.>
327 Download one of the ISO files from
328 L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-cd/>.
329 You can pick any one of the live CD variations will work, but
330 you may wish to consider the following points:
336 "C<debian-live-500-i386-rescue.iso>" is probably the best all-around
337 option for most people because it includes many extra tools such as
338 the GCC compiler, therefore saving RAM (every package you need to
339 install when running from live CD consumes memory because RAM disk is
340 being used in lieu of real disk space). When initially booting under
341 this image, you may see some cryptic warning messages having to do
342 with various diagnostic tools it tries to load or enable, but you
343 should be able to safely ignore these.
347 "C<debian-live-500-i386-standard.iso>" is a great option because of
348 its compact size, but you will probably need approximately 1 GB of RAM
349 in the computer where you will run the tutorial. Because the
350 "standard" live CD comes with with a minimal set of tools, we will
351 have to install extra packages (such as the GCC compiler), all of
352 which will require RAM when running from a live CD.
356 The other ISO images include different flavors of X-Windows desktop
357 managers. You can select one of these if you don't mind the larger
358 download size and prefer a graphical environment. Be aware that these
359 disks do not come with the extra tools found on the "rescue" image, so
360 you will need adequate RAM to be able to install them just as you
361 would under the "standard" image. B<Use one of the "graphical" ISO
362 images if you want a graphical web browser on the same machine as
363 where you will run the tutorial.> (If you are using one of the non-
364 graphical images discussed above, you can still use a graphical web
365 browser from another machine and point it to your Catalyst development
376 Select "C<Live>" from the initial boot menu.
380 Once the system has booted to a "C<user@debian:~$>" prompt, enter the
381 following command to add the more current "unstable" package
384 sudo vi /etc/apt/sources.list
386 Add the following line to the bottom of this file:
388 deb http://ftp.us.debian.org/debian/ unstable main
390 If you are not familiar with VI, you can move to the bottom of this
391 file and press the "o" key to insert a new line and type the line
392 above. Then press the "Esc" key followed by a colon (":"), the
393 letters "wq" and then the "Enter" key. The rest of the tutorial will
394 assume that you know how to use some editor that is available from the
395 Linux command-line environment.
402 sudo aptitude -y install sqlite3 libdbd-sqlite3-perl libcatalyst-perl \
403 libcatalyst-modules-perl libdbix-class-timestamp-perl \
404 libdbix-class-encodedcolumn-perl libperl6-junction-perl \
405 libdatetime-format-sqlite-perl libconfig-general-perl
407 Let it install (normally about a 30 to 90-second operaton) and you are
408 done. (Note the '\' above. Depending on your environment, you might
409 be able to cut and paste the text as shown or need to remove the '\'
410 characters to that the command is all on a single line.)
412 If you are using an image other than the "rescue" ISO, you will also need
413 to run the following command to install additional packages:
415 sudo aptitude -y install gcc make libc6-dev
417 If you are running from the Live CD, you probably also want to free up
418 some RAM disk space with the following:
422 NOTE: While the instructions above mention the Live CD because that
423 makes it easy for people new to Linux, you can obviously pick a
424 different Debian ISO image and install it to your hard drive.
425 Although there are many different ways to download and install Debian,
426 the "netinst" ISO image (such as "C<debian-500-i386-netinst.iso>"
427 represents a great option because it keeps your initial download small
428 (but still let's you install anything you want "over the network").
430 Here are some tips if you are running from a live CD and are running
431 out of disk space (which really means you are running out of RAM):
437 Always run "C<aptitude clean>" after you install new packages to
438 delete the original .deb files (the files installed B<by> the .deb
439 package B<will> remain available, just the .deb package itself is
444 If you are installing modules from CPAN, you can free up some space
445 with "C<rm -rf /root/.cpan/*>" (change "/root/" in the previous
446 command to match your home directory or the location where CPAN
447 has been configured to perform build operations).
451 If necessary, you can remove the cached package information with the
452 command "C<rm -f /var/lib/apt/lists/*>". You can later pull this
453 information again via the command "C<aptitude update>".
457 You can save a small amount of space by commenting out the lines in
458 C</etc/apt/sources.list> that reference "deb-src" and
459 "security.debian.org". If you have already done an "C<aptitude
460 update>" with these repositories enabled, you can use the tip in the
461 previous bullet to free the space up (and then do another "C<aptitude
466 Although you can free up space by removing packages you installed
467 since you last booted (check out "C<aptitude remove _pkg_name>"),
468 don't bother trying to remove packages already available at the time
469 of boot. Instead of freeing up space, it will actual I<consume> some
470 space. (The live CD uses these "burn in" packages right from the CD
471 disk vs. first loading them on the virtual RAM disk. However, if you
472 remove them, the system has to update various files, something that
473 I<does> consume some space on the virtual RAM disk.)
483 Ubuntu is an extremely popular offshoot of Debian. It provides
484 cutting edge versions of many common tools, application and libraries
485 in an easy-to-run live CD configuration (and because a single download
486 option can be used for both live CD and install-to-disk usage, it
487 keeps your download options nice and simple). As with Debian 5, you
488 should be able to generate a fully function Catalyst environment in a
489 matter of minutes. Here are quick instructions on how to use Ubuntu
490 to prepare for the tutorial:
496 Download the Ubuntu Desktop edition and boot from the CD and/or image
497 file, select your language, and then "Try Ubuntu without any changes
502 Open a terminal session (click "Applications" in the upper-left
503 corner, then "Accessories," then "Terminal").
507 Add the 'universe' repositories:
509 sudo gedit /etc/apt/sources.list
511 And remove the comments from the lines under the comments about the
512 'universe' repositories.
519 sudo aptitude install libdbd-sqlite3-perl libcatalyst-perl libcatalyst-modules-perl libconfig-general-perl
521 Accept all of the dependencies. Done.
523 If you are running from the Live CD, you probably also want to free up
524 some disk space with the following:
528 NOTE: While the instructions above mention the live CD because that
529 makes it easy for people new to Linux, you can obviously also use one
530 of the options to install Ubuntu on your drive.
536 Matt Trout's C<cat-install>
538 Available at L<http://www.shadowcat.co.uk/static/cat-install>,
539 C<cat-install> can be a fairly painless way to get Catalyst up and
540 running. Just download the script from the link above and type C<perl
541 cat-install>. Depending on the speed of your Internet connection and
542 your computer, it will probably take 30 to 60 minutes to install because
543 it downloads, makes, compiles, and tests every module. But this is an
544 excellent way to automate the installation of all the latest modules
545 used by Catalyst from CPAN.
558 The 2008 Advent Day 4 entry has more information on using OpenBSD
559 packages to quickly build a system:
560 L<http://www.catalystframework.org/calendar/2008/4>.
564 NetBSD Package Collection on Solaris
566 The 2008 Advent Day 15 entry has more information on using C<pkgsrc> and
567 NetBSD packages on Solaris:
568 L<http://www.catalystframework.org/calendar/2008/15>.
574 You can get more information at
575 L<http://www.catalystframework.org/calendar/2008/7>
576 or L<Perl::Dist::CatInABox|Perl::Dist::CatInABox>.
580 Frank Speiser's Amazon EC2 Catalyst SDK
582 There are currently two flavors of publicly available Amazon Machine
583 Images (AMI) that include all the elements you'd need to begin
584 developing in a fully functional Catalyst environment within minutes.
585 See L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>
592 For additional information and recommendations on Catalyst installation,
594 L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>.
599 This tutorial will primarily focus on SQLite because of its simplicity
600 of installation and use; however, modifications in the script required
601 to support MySQL and PostgreSQL will be presented in Appendix.
603 B<Note:> One of the advantages of the MVC design patterns is that
604 applications become much more database independent. As such, you will
605 notice that only the C<.sql> files used to initialize the database
606 change between database systems: the Catalyst code generally remains the
610 =head1 WHERE TO GET WORKING CODE
612 Each chapter of the tutorial has complete code available as a tarball in
613 the main Catalyst Subversion repository (see the note at the beginning
614 of each part for the appropriate svn command to use).
616 B<NOTE:> You can run the test cases for the final code through Chapter 8
617 with the following commands:
619 wget http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8.tgz
620 tar zxvf MyApp_Chapter8.tgz
622 CATALYST_DEBUG=0 prove --lib lib t
624 If you wish to include the L<HTML::FormFu|HTML::FormFu> section in
625 your tests, substitute C<MyApp_Chapter9_FormFu.tgz> for
626 C<MyApp_Chapter8.tgz> in the URL above.
628 wget http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter9_FormFu.tgz
629 tar zxvf MyApp_Chapter8.tgz
631 CATALYST_DEBUG=0 prove --lib lib t
633 You can also fire up the application under the development server that is conveniently
634 built in to Catalyst. Just issue this command from the C<MyApp> directory where you
635 ran the test suite above:
637 script/myapp_server.pl
639 And the application will start. You can try out the application by
640 pulling up C<http://localhost:3000> in your web browser (as mentioned
641 earlier, change C<localhost> to a different IP address or DNS name if
642 you are running your web browser and your Catalyst development on
643 different boxes). We will obviously see more about how to use the
644 application as we go through the remaining chapters of the tutorial, but
645 for now you can log in using the username "test01" and a password of
651 Kennedy Clark, C<hkclark@gmail.com>
653 Please report any errors, issues or suggestions to the author. The
654 most recent version of the Catalyst Tutorial can be found at
655 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
657 Copyright 2006-2008, Kennedy Clark, under Creative Commons License
658 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).