(Very Brief) Intro to Catalyst

http://www.catalystframework.org/

What's a Web Framework?

a software framework for developming dynamic websites

E.g. Ruby on Rails (Ruby) Django (Python)

Catalyst (Perl)

How Does It Fit?

Perl application using Catalyst

Databasee.g. MySql

Web Browser

Select * FROM.. HTTP Requests

What Is Its Structure?

Each app has a directory structure that separates model, view, and controller modules.

/lib/AppName/Model/

/lib/AppName/View/

/lib/AppName/Controller/Root.pm

/root/static/

/script/hello_server.pl

Makefile.PL

Model-View-Controller

Model: Stores and retrieves data (e.g. in a database).

Controller Receives/processes HTTP requests,

reading/manipulating data from the Model and forwarding it to the View for presentation to the user.

View Formats data for presentation to the user (usually

by generating HTML, but could also generate PDF, PNG, etc).

●Install Catalyst (Ubuntu)

sudo aptitude install libcatalyst­perl libcatalyst­modules­perl libconfig­general­perl

Create an Application

The ”catalyst.pl” script is used to create the initial application structure:

$ catalyst.pl Hello

$ cd Hello

Start the Application

$ script/hello_server.pl

View the Application

Navigate to:

http://localhost:3000

How it Works

When you access http://localhost:3000/, Catalyst calls index() in /lib/Hello/Controller/Root.pm:

sub index :Path :Args(0) {

  my ( $self, $c ) = @_;

        

  # Hello World

  $c­>response­>body( $c­>welcome_message );

}

Extending the App

Add http://localhost:3000/hello Just add a new subroutine called ”hello” to

Root.pm:

sub hello :Local {

  my ( $self, $c ) = @_;

  $c­>response­>body( ”Hello!!!!” );

}

What We've Got

If in a web browser, you query http://localhost:3000/foo,

in lib/Hello/Controller/Root.pm, a subroutine called ”foo()” is executed, and

foo() generates HTML that is sent back to the web browser.

What Else Can Catalyst Do?

Access a database (e.g. MySql) Object-Relation Mapping

Retrieve user-entered data from HTML forms Generate nice HTML using templates

E.g. Using Template::Toolkit

Integrate with the Apache web server FastCGI protocol

Questions?

http://www.catalystframework.org/ Catalyst::Manual

Thank You!

Zachary D. Blair

http://www.sfu.ca/~zblair