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> (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> or L<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 the Debian 6 Live CD, using the
191 steps in this Quick Start.
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
204 Download the C<debian-live-6.0.1-i386-rescue.iso> image from
205 L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-hybrid/>.
209 Boot this disk, either in a physical machine, or possibly some sort
210 of virtual machine (using a VM can be a very handy way to practice).
214 Select "C<Live>" from the initial boot menu.
218 At the "C<user@debian:~$>" prompt, type:
220 sudo aptitude -y install subversion
224 If you want to be able to remotely SSH to this system, set a
225 password for root (you might want to do "dpkg -l | grep openssh-server"
226 to be sure the ISO image you downloaded has the SSH daemon installed...
227 if it's missing, do a "sudo aptitude -y install openssh-server"):
234 Add the "unstable" Debian package repository:
236 sudo vi /etc/apt/sources.list
238 Add the following line to the bottom of this file:
240 deb http://ftp.us.debian.org/debian/ unstable main
244 Install Catalyst and related libraries:
247 sudo aptitude -y install libcatalyst-perl libdatetime-format-sqlite-perl \
248 libdbix-class-encodedcolumn-perl sqlite3 libcatalyst-modules-perl \
249 libperl6-junction-perl libcatalyst-modules-extra-perl \
250 libdbix-class-timestamp-perl
259 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
260 cd MyApp_Chapter8/MyApp
261 CATALYST_DEBUG=0 prove -wl t
267 =head1 VERSIONS AND CONVENTIONS USED IN THIS TUTORIAL
269 This tutorial was built using the following resources. Please note that
270 you may need to make adjustments for different environments and versions
271 (note that trailing zeros in version numbers are not significant and may
272 get dropped with some techniques for viewing them; for example, Catalyst
273 v5.80020 might show up as 5.8002):
287 Catalyst::Devel v1.28
295 Catalyst::Model::DBIC::Schema v0.41
299 Template Toolkit v2.22
304 HTML::FormFu -- v0.07002
308 B<NOTE:> You can check the versions you have installed with the
309 following command (note the slash before the space):
311 perl -M<_mod_name_>\ 999
315 perl -M<_mod_name_> -e 'print "$<_mod_name_>::VERSION\n"'
319 perl -MCatalyst::Devel\ 999
323 perl -MCatalyst::Devel -e 'print "$Catalyst::Devel::VERSION\n";'
327 This tutorial will assume that the web browser is located on the same
328 system where the Catalyst development server is running, and therefore
329 use a URL of C<http://localhost:3000> (the Catalyst development server
330 defaults to port 3000, but can be changed with the "-p" option to the
331 development server). If you are running Perl on a different box than
332 where your web browser is located (or using a different port number via
333 the C<-p> I<port_number> option to the development server), then you
334 will need to update the URL you use accordingly.
336 Please Note: Depending on the web browser you are using, you might need
337 to hit C<Shift+Reload> or C<Ctrl+Reload> to pull a fresh page when
338 testing your application at various points (see
339 L<http://en.wikipedia.org/wiki/Bypass_your_cache> for a comprehensive
340 list of options for each browser). Also, the C<-k> keepalive option to
341 the development server can be necessary with some browsers (especially
342 Internet Explorer). ***Todo: is this still true?
347 =head1 CATALYST INSTALLATION
349 Although Catalyst installation has been a challenge in the past, the
350 good news is that there are a growing number of options to eliminate (or
351 at least dramatically simplify) this concern. Although a compelling
352 strength of Catalyst is that it makes use of many of the modules in the
353 vast repository that is CPAN, this can complicate the installation
354 process if you approach it in the wrong way. Consider the following
355 suggestions on the most common ways to get started with a Catalyst
356 development environment:
364 The Debian 6 Live CD represents a great way for newcomers to experiment
365 with Catalyst. As a "live CD," you can simple boot from the CD, run a
366 few commands, and in a matter of minutes you should have a fully
367 function environment in which do this tutorial. B<The tutorial was fully
368 tested to work under Debian 6. Although it SHOULD work under any
369 Catalyst installation method you might choose, it can be hard to
376 Download one of the ISO files from
377 L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-hybrid/>
378 (the current version at the time this was written was 6.0.1). You can
379 pick any one of the live CD variations will work, but you may wish to
380 consider the following points:
386 "C<debian-live-6.0.1-i386-rescue.iso>" is probably the best all-around
387 option for most people because it includes many extra tools such as the
388 GCC compiler, therefore saving RAM (every package you need to install
389 when running from a Live CD consumes memory because RAM disk is being
390 used in lieu of real disk space). When initially booting under this
391 image, you may see some cryptic warning messages having to do with
392 various diagnostic tools it tries to load or enable, but you should be
393 able to safely ignore these.
397 "C<debian-live-6.0.1-i386-standard.iso>" is a great option because of
398 its compact size, but you will probably need approximately 1 GB of RAM
399 in the computer where you will run the tutorial. Because the "standard"
400 live CD comes with with a minimal set of tools, we will have to install
401 extra packages (such as the GCC compiler), all of which will require RAM
402 when running from a live CD.
406 The other ISO images include different flavors of X-Windows desktop
407 managers. You can select one of these if you don't mind the larger
408 download size and prefer a graphical environment. Be aware that these
409 disks do not come with the extra tools found on the "rescue" image, so
410 you will need adequate RAM to be able to install them just as you would
411 under the "standard" image. B<Use one of the "graphical" ISO images if
412 you want a graphical web browser on the same machine as where you will
413 run the tutorial.> (If you are using one of the non- graphical images
414 discussed above, you can still use a graphical web browser from another
415 machine and point it to your Catalyst development machine.)
425 Select "C<Live>" from the initial boot menu.
429 Once the system has booted to a "C<user@debian:~$>" prompt, first
430 install the Subversion client in case you want to check out the
431 completed chapter example code:
433 sudo aptitude -y install subversion
435 If you want to be able to remotely SSH to this system, set a
441 Then enter the following command to add the more current "unstable"
442 package repository so we get the latest versions of Catalyst and related
445 sudo vi /etc/apt/sources.list
447 Add the following line to the bottom of this file:
449 deb http://ftp.us.debian.org/debian/ unstable main
451 If you are not familiar with VI, you can move to the bottom of this file
452 and press the "o" key to insert a new line and type the line above.
453 Then press the "Esc" key followed by a colon (":"), the letters "wq" and
454 then the "Enter" key. The rest of the tutorial will assume that you
455 know how to use some editor that is available from the Linux
456 command-line environment.
463 sudo aptitude -y install libcatalyst-perl libdatetime-format-sqlite-perl \
464 libdbix-class-encodedcolumn-perl sqlite3 libcatalyst-modules-perl \
465 libperl6-junction-perl libcatalyst-modules-extra-perl \
466 libdbix-class-timestamp-perl
468 Let it install (normally about a 30 to 90-second operation) and you are
469 done. (Note the '\' above. Depending on your environment, you might be
470 able to cut and paste the text as shown or need to remove the '\'
471 characters to that the command is all on a single line.)
473 If you are using an image other than the "rescue" ISO, you will also need
474 to run the following command to install additional packages:
476 sudo aptitude -y install gcc make libc6-dev
478 If you are running from the Live CD, you probably also want to free up
479 some RAM disk space with the following:
483 NOTE: While the instructions above mention the Live CD because that
484 makes it easy for people new to Linux, you can obviously pick a
485 different Debian ISO image and install it to your hard drive. Although
486 there are many different ways to download and install Debian, the
487 "netinst" ISO image (such as "C<debian-500-i386-netinst.iso>" represents
488 a great option because it keeps your initial download small (but still
489 lets you install anything you want "over the network").
491 Here are some tips if you are running from a live CD and are running
492 out of disk space (which really means you are running out of RAM):
498 Always run "C<aptitude clean>" after you install new packages to delete
499 the original .deb files (the files installed B<by> the .deb package
500 B<will> remain available, just the .deb package itself is deleted).
504 If you are installing modules from CPAN, you can free up some space with
505 "C<rm -rf /root/.cpan/*>" (change "/root/" in the previous command to
506 match your home directory or the location where CPAN has been configured
507 to perform build operations).
511 If necessary, you can remove the cached package information with the
512 command "C<rm -f /var/lib/apt/lists/*>". You can later pull this
513 information again via the command "C<aptitude update>".
517 You can save a small amount of space by commenting out the lines in
518 C</etc/apt/sources.list> that reference "deb-src" and
519 "security.debian.org". If you have already done an "C<aptitude update>"
520 with these repositories enabled, you can use the tip in the previous
521 bullet to free the space up (and then do another "C<aptitude update>").
525 Although you can free up space by removing packages you installed since
526 you last booted (check out "C<aptitude remove _pkg_name_>"), don't bother
527 trying to remove packages already available at the time of boot. Instead
528 of freeing up space, it will actual consume I<more> space. (The live CD
529 uses these "burn in" packages right from the CD disk vs. first loading
530 them on the virtual RAM disk. However, if you remove them, the system
531 has to update various files, something that I<does> consume some space
532 on the virtual RAM disk.)
542 Ubuntu is a popular offshoot of Debian. It provides cutting edge
543 versions of many common tools, application and libraries in an
544 easy-to-run live CD configuration (and because a single download option
545 can be used for both live CD and install-to-disk usage, it keeps your
546 download options nice and simple). As with Debian 6, you should be able
547 to generate a fully function Catalyst environment in a matter of
548 minutes. Here are quick instructions on how to use Ubuntu to prepare
555 Download the Ubuntu Desktop edition and boot from the CD and/or image
556 file, select your language, and then "Try Ubuntu without any changes to
561 Open a terminal session (click "Applications" in the upper-left corner,
562 then "Accessories," then "Terminal").
566 Add the 'universe' repositories:
568 sudo gedit /etc/apt/sources.list
570 And remove the comments from the lines under the comments about the
571 'universe' repositories.
578 sudo aptitude install libdbd-sqlite3-perl libcatalyst-perl libcatalyst-modules-perl libconfig-general-perl
580 Accept all of the dependencies. Done.
582 If you are running from the Live CD, you probably also want to free up
583 some disk space with the following:
587 NOTE: While the instructions above mention the live CD because that
588 makes it easy for people new to Linux, you can obviously also use one of
589 the options to install Ubuntu on your drive.
595 Matt Trout's C<cat-install>
597 Available at L<http://www.shadowcat.co.uk/static/cat-install>,
598 C<cat-install> can be a fairly painless way to get Catalyst up and
599 running. Just download the script from the link above and type
600 C<perl cat-install>. Depending on the speed of your Internet connection
601 and your computer, it will probably take 30 to 60 minutes to install
602 because it downloads, makes, compiles, and tests every module. But this
603 is an excellent way to automate the installation of all the latest
604 modules used by Catalyst from CPAN.
617 The 2008 Advent Day 4 entry has more information on using OpenBSD
618 packages to quickly build a system:
619 L<http://www.catalystframework.org/calendar/2008/4>.
623 NetBSD Package Collection on Solaris
625 The 2008 Advent Day 15 entry has more information on using C<pkgsrc> and
626 NetBSD packages on Solaris:
627 L<http://www.catalystframework.org/calendar/2008/15>.
633 You can get more information at
634 L<http://www.catalystframework.org/calendar/2008/7> or
635 L<Perl::Dist::CatInABox>.
639 Frank Speiser's Amazon EC2 Catalyst SDK
641 There are currently two flavors of publicly available Amazon Machine
642 Images (AMI) that include all the elements you'd need to begin
643 developing in a fully functional Catalyst environment within minutes.
644 See L<Catalyst::Manual::Installation>
651 For additional information and recommendations on Catalyst installation,
653 L<Catalyst::Manual::Installation>.
658 This tutorial will primarily focus on SQLite because of its simplicity
659 of installation and use; however, modifications in the script required
660 to support MySQL and PostgreSQL will be presented in the Appendix.
662 B<Note:> One of the advantages of using tools like Catalyst and DBIC is
663 that applications become much more database independent. As such, you
664 will notice that only the C<.sql> files used to initialize the database
665 change between database systems: most of the code generally remains the
669 =head1 WHERE TO GET WORKING CODE
671 Each chapter of the tutorial has complete code available as a tarball in
672 the main Catalyst Subversion repository (see the note at the beginning
673 of each part for the appropriate svn command to use).
675 B<NOTE:> You can run the test cases for the final code through Chapter 8
676 with the following commands:
678 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
679 cd MyApp_Chapter8/MyApp
680 CATALYST_DEBUG=0 prove -wl t
682 If you wish to include the L<HTML::FormFu> section in your tests,
683 substitute C<MyApp_Chapter9_FormFu> for C<MyApp_Chapter8> in the URL
684 above (don't forget to "cd" out of the Ch8 directory if you ran the code above).
686 svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter9_FormFu
687 cd MyApp_Chapter9_FormFu/MyApp
688 CATALYST_DEBUG=0 prove -wl t
690 You can also fire up the application under the development server that is conveniently
691 built in to Catalyst. Just issue this command from the C<MyApp> directory where you
692 ran the test suite above:
694 script/myapp_server.pl
696 And the application will start. You can try out the application by
697 pulling up C<http://localhost:3000> in your web browser (as mentioned
698 earlier, change C<localhost> to a different IP address or DNS name if
699 you are running your web browser and your Catalyst development on
700 different boxes). We will obviously see more about how to use the
701 application as we go through the remaining chapters of the tutorial, but
702 for now you can log in using the username "test01" and a password of
708 Kennedy Clark, C<hkclark@gmail.com>
710 Please report any errors, issues or suggestions to the author. The
711 most recent version of the Catalyst Tutorial can be found at
712 L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
714 Copyright 2006-2010, Kennedy Clark, under the
715 Creative Commons Attribution Share-Alike License Version 3.0
716 (L<http://creativecommons.org/licenses/by-sa/3.0/us/>).