=head1 NAME
Catalyst::Manual::Tutorial::01_Intro - Catalyst Tutorial - Chapter 1: Introduction
=head1 OVERVIEW
This is B<Chapter 1 of 10> for the Catalyst tutorial.
L<Tutorial Overview|Catalyst::Manual::Tutorial>
=over 4
=item 1
B<01_Introduction>
=item 2
L<Catalyst Basics|Catalyst::Manual::Tutorial::02_CatalystBasics>
=item 3
L<More Catalyst Basics|Catalyst::Manual::Tutorial::03_MoreCatalystBasics>
=item 4
L<Basic CRUD|Catalyst::Manual::Tutorial::04_BasicCRUD>
=item 5
L<Authentication|Catalyst::Manual::Tutorial::05_Authentication>
=item 6
L<Authorization|Catalyst::Manual::Tutorial::06_Authorization>
=item 7
L<Debugging|Catalyst::Manual::Tutorial::07_Debugging>
=item 8
L<Testing|Catalyst::Manual::Tutorial::08_Testing>
=item 9
L<Advanced CRUD|Catalyst::Manual::Tutorial::09_AdvancedCRUD>
=item 10
L<Appendices|Catalyst::Manual::Tutorial::10_Appendices>
=back
=head1 DESCRIPTION
This tutorial provides a multi-part introduction to the Catalyst web
framework. It seeks to provide a rapid overview of many of its most
commonly used features. The focus is on the real-world best practices
required in the construction of nearly all Catalyst applications.
Although the primary target of the tutorial is users new to the Catalyst
framework, experienced users may wish to review specific sections (for
example, how to use DBIC for their model classes, how to add
authentication and authorization to an existing application, or form
management).
You can obtain the code for all the tutorial examples from the
catalyst subversion repository by issuing the command:
svn co http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial/ CatalystTutorial
This will download the most recent code for each chapter of the
tutorial into the CatalystTutorial directory on your machine.
B<These reference implementations are provided so that when you follow
the tutorial, you can use the code from the subversion repository to
ensure that your system is set up correctly, and that you have not
inadvertently made any typographic errors, or accidentally skipped
part of the tutorial.>
B<NOTE: You can use any Perl-supported OS and environment to run
Catalyst.> It should make little or no difference to Catalyst's
operation, B<but this tutorial has been written using the Debian 5
live CD> because that represents a quick and easy way for most people to
try out Catalyst with virtually zero setup time and hassles. Also,
the tutorial has been tested to work correctly with the versions of
Catalyst and all the supporting modules in Debian 5 (see "VERSIONS
AND CONVENTIONS USED IN THIS TUTORIAL" below for the specific versions
for some of the key modules), so B<if you think you might be running
into an issue related to versions> (for example, a module changed its
behavior in a newer version or a bug was introduced), B<it might be
worth giving Debian 5 a try>.
If you plan to follow along with Debian 5, you can jump down to the
"Debian" section under L</"CATALYST INSTALLATION"> below and it will walk you
though the setup of a fully functional Catalyst environment. If you
would prefer to install directly from CPAN, you can download the example
program and all the necessary dependencies to your local machine by
installing the C<Task::Catalyst::Tutorial> distribution:
cpan Task::Catalyst::Tutorial
This will also test to make sure the dependencies are working. If you
have trouble installing these, please ask for help on the #catalyst
IRC channel, or the Catalyst mailing list.
Subjects covered by the tutorial include:
=over 4
=item *
A simple application that lists and adds books.
=item *
The use of L<DBIx::Class|DBIx::Class> (DBIC) for the model (including
some of the more advanced techniques you will probably want to use in
your applications).
=item *
How to write CRUD (Create, Read, Update, and Delete) operations in
Catalyst.
=item *
Authentication ("auth").
=item *
Role-based authorization ("authz").
=item *
Attempts to provide an example showing current (5.8XXX) Catalyst
practices. For example, the use of
L<Catalyst::Action::RenderView|Catalyst::Action::RenderView>,
DBIC, L<Catalyst::Plugin::ConfigLoader|Catalyst::Plugin::ConfigLoader>
with C<myapp.conf>, the use of C<lib/MyApp/Controller/Root.pm>
vs. C<lib/MyApp.pm>, etc.
=item *
The use of Template Toolkit (TT).
=item *
Useful techniques for troubleshooting and debugging Catalyst
applications.
=item *
The use of SQLite as a database (with code also provided for MySQL and
PostgreSQL). (Note: Because we make use of the DBIx::Class Object
Relational Mapping [ORM] layer, out our application will be database
agnostic and can easily be used by any of the databases supported
by DBIx::Class.)
=item *
The use of L<HTML::FormFu|HTML::FormFu> or L<HTML::FormHandler|HTML::FormHandler>
for automated form processing and validation.
=back
This tutorial makes the learning process its main priority. For
example, the level of comments in the code found here would likely be
considered excessive in a "normal project." Because of their contextual
value, this tutorial will generally favor inline comments over a
separate discussion in the text. It also deliberately tries to
demonstrate multiple approaches to various features (in general, you
should try to be as consistent as possible with your own production
code).
Furthermore, this tutorial tries to minimize the number of controllers,
models, TT templates, and database tables. Although this does result in
things being a bit contrived at times, the concepts should be applicable
to more complex environments. More complete and complicated example
applications can be found in the C<examples> area of the Catalyst
Subversion repository at
L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/>.
=head1 QUICK START
For those who want to get going quickly, here is a short "cookbook-style
recipe" to quickly get you up and running. Although there are many
different ways to get a Catalyst environment going, this tutorial has
been written with and tested against Debian 5 Live CD, using the steps
in this Quick Start.
If you want, you can follow the directions in this section and then jump
right to L<Chapter 2|Catalyst::Manual::Tutorial::02_CatalystBasics> of
the tutorial. However, it would be a good idea to come back and read the
sections below the Quick Start when you have time. Or, continue reading
those other sections for suggestions if you do not wish to use the
Debian 5 Live CD.
=over 4
=item 1
Download the C<debian-live-503-i386-rescue.iso> image from
L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-cd/>.
=item 2
Boot this disk, either in a physical machine, or possibly some sort
of virtual machine (can be a very handy way to practice).
=item 3
Select "C<Live>" from the initial boot menu.
=item 4
At the "C<user@debian:~$>" prompt, type:
sudo aptitude -y install subversion
=item 5
If you want to be able to remotely SSH to this system, set a
password for root:
sudo passwd
...
=item 6
Add the "unstable" Debian package repository:
sudo vi /etc/apt/sources.list
Add the following line to the bottom of this file:
deb http://ftp.us.debian.org/debian/ unstable main
=item 7
Install Catalyst and related libraries:
sudo aptitude update
sudo aptitude -y install sqlite3 libdbd-sqlite3-perl libcatalyst-perl \
libcatalyst-modules-perl libdbix-class-timestamp-perl \
libdatetime-format-sqlite-perl libconfig-general-perl \
libhtml-formfu-model-dbic-perl libterm-readline-perl-perl \
libdbix-class-encodedcolumn-perl libperl6-junction-perl \
libtest-pod-perl
sudo aptitude clean
=item 8
Test example code:
mkdir test
cd test
svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
cd MyApp_Chapter8/MyApp
CATALYST_DEBUG=0 prove -wl t
cd
=back
=head1 VERSIONS AND CONVENTIONS USED IN THIS TUTORIAL
This tutorial was built using the following resources. Please note that
you may need to make adjustments for different environments and
versions (note that trailing zeros in version numbers are not
significant and may get dropped with techniques for viewing them;
for example, Catalyst v5.80020 might show up as 5.8002):
=over 4
=item *
Debian 5 (Lenny)
=item *
Catalyst v5.80020 (note: may show up as '5.8002' without the trailing zero)
=item *
Catalyst::Devel v1.26
=item *
DBIx::Class v0.08115
=item *
Catalyst::Model::DBIC::Schema v0.40
=item *
Template Toolkit v2.20
=item *
Catalyst Plugins
The plugins used in this tutorial all have sufficiently stable APIs that
you shouldn't need to worry about versions. However, there could be
cases where the tutorial is affected by what version of plugins you
use. This tutorial has been tested against the following set of plugins:
=over 4
=item *
Catalyst::Plugin::Authentication -- v0.10016
=item *
Catalyst::Plugin::Authorization::Roles -- v0.08
=item *
Catalyst::Plugin::ConfigLoader -- v0.27
=item *
Catalyst::Plugin::Session -- v0.29
=item *
Catalyst::Plugin::Session::State::Cookie -- v0.17
=item *
Catalyst::Plugin::Session::Store::FastMmap -- v0.13
=item *
Catalyst::Plugin::StackTrace -- v0.11
=item *
Catalyst::Plugin::Static::Simple -- v0.29
=back
=item *
HTML::FormFu -- v0.06001
=item *
B<NOTE:> You can check the versions you have installed with the
following command:
perl -M<_mod_name_> -e '"print $<_mod_name_>::VERSION\n"'
For example:
perl -MCatalyst -e 'print "$Catalyst::VERSION\n";'
or:
perl -MCatalyst::Devel -e 'print "$Catalyst::Devel::VERSION\n";'
=item *
This tutorial will assume that the web browser is located on the same
system where the Catalyst development server is running, and
therefore use a URL of C<http://localhost:3000> (the Catalyst
development server defaults to port 3000). If you are running Perl on
a different box than where your web browser is located (or using a
different port number via the C<-p> I<port_number> option to the
development server), then you will need to update the URL you use
accordingly.
Please Note: Depending on the web browser you are using, you might
need to hit C<Shift+Reload> or C<Ctrl+Reload> to pull a fresh page
when testing your application at various points (see
L<http://en.wikipedia.org/wiki/Bypass_your_cache> for a comprehensive
list of options for each browser). Also, the C<-k> keepalive option
to the development server can be necessary with some browsers
(especially Internet Explorer).
=back
=head1 CATALYST INSTALLATION
Although Catalyst installation has been a challenge in the past, the
good news is that there are a growing number of options to eliminate
(or at least dramatically simplify) this concern. Although a
compelling strength of Catalyst is that it makes use of many of the
modules in the vast repository that is CPAN, this can complicate the
installation process if you approach it in the wrong way. Consider
the following suggestions on the most common ways to get started with
a Catalyst development environment:
=over 4
=item *
Debian
The Debian 5 live CD represents a great way for newcomers to
experiment with Catalyst. As a "live CD," you can simple boot from
the CD, run a few commands, and in a matter of minutes you should have
a fully function environment in which do this tutorial. B<The tutorial
was fully tested to work under Debian 5. Although it SHOULD work
under any Catalyst installation method you might choose, it can be
hard to guarantee this.>
=over 4
=item *
Download one of the ISO files from
L<http://cdimage.debian.org/cdimage/release/current-live/i386/iso-cd/>
(the current version at the time this was written was 5.0.3).
You can pick any one of the live CD variations will work, but
you may wish to consider the following points:
=over 4
=item *
"C<debian-live-503-i386-rescue.iso>" is probably the best all-around
option for most people because it includes many extra tools such as
the GCC compiler, therefore saving RAM (every package you need to
install when running from live CD consumes memory because RAM disk is
being used in lieu of real disk space). When initially booting under
this image, you may see some cryptic warning messages having to do
with various diagnostic tools it tries to load or enable, but you
should be able to safely ignore these.
=item *
"C<debian-live-503-i386-standard.iso>" is a great option because of
its compact size, but you will probably need approximately 1 GB of RAM
in the computer where you will run the tutorial. Because the
"standard" live CD comes with with a minimal set of tools, we will
have to install extra packages (such as the GCC compiler), all of
which will require RAM when running from a live CD.
=item *
The other ISO images include different flavors of X-Windows desktop
managers. You can select one of these if you don't mind the larger
download size and prefer a graphical environment. Be aware that these
disks do not come with the extra tools found on the "rescue" image, so
you will need adequate RAM to be able to install them just as you
would under the "standard" image. B<Use one of the "graphical" ISO
images if you want a graphical web browser on the same machine as
where you will run the tutorial.> (If you are using one of the non-
graphical images discussed above, you can still use a graphical web
browser from another machine and point it to your Catalyst development
machine.)
=back
=item *
Boot off the CD.
=item *
Select "C<Live>" from the initial boot menu.
=item *
Once the system has booted to a "C<user@debian:~$>" prompt, first
install the Subversion client in case you want to check out the
completed chapter example code:
sudo aptitude -y install subversion
If you want to be able to remotely SSH to this system, set a
password for root:
sudo passwd
...
Then enter the following command to add the more current "unstable"
package repository so we get the latest versions of Catalyst and
related packages:
sudo vi /etc/apt/sources.list
Add the following line to the bottom of this file:
deb http://ftp.us.debian.org/debian/ unstable main
If you are not familiar with VI, you can move to the bottom of this
file and press the "o" key to insert a new line and type the line
above. Then press the "Esc" key followed by a colon (":"), the
letters "wq" and then the "Enter" key. The rest of the tutorial will
assume that you know how to use some editor that is available from the
Linux command-line environment.
=item *
Install Catalyst:
sudo aptitude update
sudo aptitude -y install sqlite3 libdbd-sqlite3-perl libcatalyst-perl \
libcatalyst-modules-perl libdbix-class-timestamp-perl \
libdatetime-format-sqlite-perl libconfig-general-perl \
libhtml-formfu-model-dbic-perl libterm-readline-perl-perl \
libdbix-class-encodedcolumn-perl libperl6-junction-perl \
libtest-pod-perl
Let it install (normally about a 30 to 90-second operaton) and you are
done. (Note the '\' above. Depending on your environment, you might
be able to cut and paste the text as shown or need to remove the '\'
characters to that the command is all on a single line.)
If you are using an image other than the "rescue" ISO, you will also need
to run the following command to install additional packages:
sudo aptitude -y install gcc make libc6-dev
If you are running from the Live CD, you probably also want to free up
some RAM disk space with the following:
sudo aptitude clean
NOTE: While the instructions above mention the Live CD because that
makes it easy for people new to Linux, you can obviously pick a
different Debian ISO image and install it to your hard drive.
Although there are many different ways to download and install Debian,
the "netinst" ISO image (such as "C<debian-500-i386-netinst.iso>"
represents a great option because it keeps your initial download small
(but still let's you install anything you want "over the network").
Here are some tips if you are running from a live CD and are running
out of disk space (which really means you are running out of RAM):
=over 4
=item *
Always run "C<aptitude clean>" after you install new packages to
delete the original .deb files (the files installed B<by> the .deb
package B<will> remain available, just the .deb package itself is
deleted).
=item *
If you are installing modules from CPAN, you can free up some space
with "C<rm -rf /root/.cpan/*>" (change "/root/" in the previous
command to match your home directory or the location where CPAN
has been configured to perform build operations).
=item *
If necessary, you can remove the cached package information with the
command "C<rm -f /var/lib/apt/lists/*>". You can later pull this
information again via the command "C<aptitude update>".
=item *
You can save a small amount of space by commenting out the lines in
C</etc/apt/sources.list> that reference "deb-src" and
"security.debian.org". If you have already done an "C<aptitude
update>" with these repositories enabled, you can use the tip in the
previous bullet to free the space up (and then do another "C<aptitude
update>").
=item *
Although you can free up space by removing packages you installed
since you last booted (check out "C<aptitude remove _pkg_name>"),
don't bother trying to remove packages already available at the time
of boot. Instead of freeing up space, it will actual I<consume> some
space. (The live CD uses these "burn in" packages right from the CD
disk vs. first loading them on the virtual RAM disk. However, if you
remove them, the system has to update various files, something that
I<does> consume some space on the virtual RAM disk.)
=back
=back
=item *
Ubuntu
Ubuntu is an extremely popular offshoot of Debian. It provides
cutting edge versions of many common tools, application and libraries
in an easy-to-run live CD configuration (and because a single download
option can be used for both live CD and install-to-disk usage, it
keeps your download options nice and simple). As with Debian 5, you
should be able to generate a fully function Catalyst environment in a
matter of minutes. Here are quick instructions on how to use Ubuntu
to prepare for the tutorial:
=over 4
=item *
Download the Ubuntu Desktop edition and boot from the CD and/or image
file, select your language, and then "Try Ubuntu without any changes
to your computer."
=item *
Open a terminal session (click "Applications" in the upper-left
corner, then "Accessories," then "Terminal").
=item *
Add the 'universe' repositories:
sudo gedit /etc/apt/sources.list
And remove the comments from the lines under the comments about the
'universe' repositories.
=item *
Install Catalyst:
sudo aptitude update
sudo aptitude install libdbd-sqlite3-perl libcatalyst-perl libcatalyst-modules-perl libconfig-general-perl
Accept all of the dependencies. Done.
If you are running from the Live CD, you probably also want to free up
some disk space with the following:
sudo aptitude clean
NOTE: While the instructions above mention the live CD because that
makes it easy for people new to Linux, you can obviously also use one
of the options to install Ubuntu on your drive.
=back
=item *
Matt Trout's C<cat-install>
Available at L<http://www.shadowcat.co.uk/static/cat-install>,
C<cat-install> can be a fairly painless way to get Catalyst up and
running. Just download the script from the link above and type C<perl
cat-install>. Depending on the speed of your Internet connection and
your computer, it will probably take 30 to 60 minutes to install because
it downloads, makes, compiles, and tests every module. But this is an
excellent way to automate the installation of all the latest modules
used by Catalyst from CPAN.
=item *
Other Possibilities
=over 4
=item *
OpenBSD Packages
The 2008 Advent Day 4 entry has more information on using OpenBSD
packages to quickly build a system:
L<http://www.catalystframework.org/calendar/2008/4>.
=item *
NetBSD Package Collection on Solaris
The 2008 Advent Day 15 entry has more information on using C<pkgsrc> and
NetBSD packages on Solaris:
L<http://www.catalystframework.org/calendar/2008/15>.
=item *
CatInABox
You can get more information at
L<http://www.catalystframework.org/calendar/2008/7>
or L<Perl::Dist::CatInABox|Perl::Dist::CatInABox>.
=item *
Frank Speiser's Amazon EC2 Catalyst SDK
There are currently two flavors of publicly available Amazon Machine
Images (AMI) that include all the elements you'd need to begin
developing in a fully functional Catalyst environment within minutes.
See L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>
for more details.
=back
=back
For additional information and recommendations on Catalyst installation,
please refer to
L<Catalyst::Manual::Installation|Catalyst::Manual::Installation>.
=head1 DATABASES
This tutorial will primarily focus on SQLite because of its simplicity
of installation and use; however, modifications in the script required
to support MySQL and PostgreSQL will be presented in Appendix.
B<Note:> One of the advantages of the MVC design patterns is that
applications become much more database independent. As such, you will
notice that only the C<.sql> files used to initialize the database
change between database systems: the Catalyst code generally remains the
same.
=head1 WHERE TO GET WORKING CODE
Each chapter of the tutorial has complete code available as a tarball in
the main Catalyst Subversion repository (see the note at the beginning
of each part for the appropriate svn command to use).
B<NOTE:> You can run the test cases for the final code through Chapter 8
with the following commands:
svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter8
cd MyApp_Chapter8/MyApp
CATALYST_DEBUG=0 prove -wl t
If you wish to include the L<HTML::FormFu|HTML::FormFu> section in your tests,
substitute C<MyApp_Chapter9_FormFu> for C<MyApp_Chapter8> in the URL
above (don't forget to "cd" out of the Ch8 directory if you ran the code above).
svn co http://dev.catalystframework.org/repos/Catalyst/trunk/examples/Tutorial/MyApp_Chapter9_FormFu
cd MyApp_Chapter9_FormFu/MyApp
CATALYST_DEBUG=0 prove -wl t
You can also fire up the application under the development server that is conveniently
built in to Catalyst. Just issue this command from the C<MyApp> directory where you
ran the test suite above:
script/myapp_server.pl
And the application will start. You can try out the application by
pulling up C<http://localhost:3000> in your web browser (as mentioned
earlier, change C<localhost> to a different IP address or DNS name if
you are running your web browser and your Catalyst development on
different boxes). We will obviously see more about how to use the
application as we go through the remaining chapters of the tutorial, but
for now you can log in using the username "test01" and a password of
"mypass".
=head1 AUTHOR
Kennedy Clark, C<hkclark@gmail.com>
Please report any errors, issues or suggestions to the author. The
most recent version of the Catalyst Tutorial can be found at
L<http://dev.catalyst.perl.org/repos/Catalyst/Catalyst-Manual/5.80/trunk/lib/Catalyst/Manual/Tutorial/>.
Copyright 2006-2008, Kennedy Clark, under Creative Commons License
(L<http://creativecommons.org/licenses/by-sa/3.0/us/>).