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Catalyst::Manual::Tutorial::01_Intro - Catalyst Tutorial - Chapter 1: Introduction


This is Chapter 1 of 10 for the Catalyst tutorial.

Tutorial Overview

  1. 01_Introduction
  2. Catalyst Basics
  3. More Catalyst Basics
  4. Basic CRUD
  5. Authentication
  6. Authorization
  7. Debugging
  8. Testing
  9. Advanced CRUD
  10. Appendices


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 CatalystTutorial

This will download the most recent code for each chapter of the tutorial into the CatalystTutorial directory on your machine.

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.

NOTE: You can use any Perl-supported OS and environment to run Catalyst. It should make little or no difference to Catalyst's operation, 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 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), 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 "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 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:

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 examples area of the Catalyst Subversion repository at


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 Chapter 2 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.

  1. Download the debian-live-503-i386-rescue.iso image from
  2. Boot this disk, either in a physical machine, or possibly some sort of virtual machine (can be a very handy way to practice).
  3. Select "Live" from the initial boot menu.
  4. At the "user@debian:~$" prompt, type:
        sudo aptitude -y install subversion
  5. If you want to be able to remotely SSH to this system, set a password for root:
        sudo passwd
  6. Add the "unstable" Debian package repository:
        sudo vi /etc/apt/sources.list

    Add the following line to the bottom of this file:

        deb unstable main
  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 \
        sudo aptitude clean
  8. Test example code:
        mkdir test
        cd test
        svn co
        cd MyApp_Chapter8/MyApp
        CATALYST_DEBUG=0 prove -wl t


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):


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:

For additional information and recommendations on Catalyst installation, please refer to Catalyst::Manual::Installation.


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.

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 .sql files used to initialize the database change between database systems: the Catalyst code generally remains the same.


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).

NOTE: You can run the test cases for the final code through Chapter 8 with the following commands:

    svn co
    cd MyApp_Chapter8/MyApp
    CATALYST_DEBUG=0 prove -wl t

If you wish to include the HTML::FormFu section in your tests, substitute MyApp_Chapter9_FormFu for MyApp_Chapter8 in the URL above (don't forget to "cd" out of the Ch8 directory if you ran the code above).

    svn co
    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 MyApp directory where you ran the test suite above:


And the application will start. You can try out the application by pulling up http://localhost:3000 in your web browser (as mentioned earlier, change 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".


Kennedy Clark,

Please report any errors, issues or suggestions to the author. The most recent version of the Catalyst Tutorial can be found at

Copyright 2006-2008, Kennedy Clark, under Creative Commons License (

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