NAME

Catalyst::Manual::Tutorial - Getting started with Catalyst

DESCRIPTION

This document aims to get you up and running with Catalyst.

NOTE: THIS DOCUMENT IS STILL VERY MUCH AT AN ALPHA STAGE.

Please send comments, corrections and suggestions for improvements to A.Ford@ford-mason.co.uk

Installation

The first step is to install Catalyst, and the simplest way to do this is to install the Catalyst bundle from CPAN:

    $ perl -MCPAN -e 'install Bundle::Catalyst'

This will retrieve Catalyst and a number of useful extensions and install them for you.

Setting up your application

Catalyst includes a helper script, catalyst.pl, that will set up a skeleton application for you:

    $ catalyst.pl My::App
    created "My-App"
    created "My-App/script"
    created "My-App/lib"
    created "My-App/root"
    created "My-App/t"
    created "My-App/t/m"
    created "My-App/t/v"
    created "My-App/t/c"
    created "My-App/lib/My/App"
    created "My-App/lib/My/App/M"
    created "My-App/lib/My/App/V"
    created "My-App/lib/My/App/C"
    created "My-App/lib/My/App.pm"
    created "My-App/Makefile.PL"
    created "My-App/README"
    created "My-App/Changes"
    created "My-App/t/01app.t"
    created "My-App/t/02podcoverage.t"
    created "My-App/script/cgi.pl"
    created "My-App/script/nph-cgi.pl"
    created "My-App/script/fcgi.pl"
    created "My-App/script/server.pl"
    created "My-App/script/test.pl"
    created "My-App/script/create.pl"

This creates the directory structure shown.

Testing out the sample application

You can test out your new application by running the server script that catalyst provides:

    $ cd My-App
    $ script/server.pl 
    [Sun Mar 20 12:31:18 2005] [catalyst] [debug] Debug messages enabled
    [Sun Mar 20 12:31:18 2005] [catalyst] [debug] Loaded engine "Catalyst::Engine::CGI"
    [Sun Mar 20 12:31:18 2005] [catalyst] [debug] Initialized components ""
    [Sun Mar 20 12:31:18 2005] [catalyst] [info] My::App powered by Catalyst 4.26
    [Sun Mar 20 12:31:18 2005] [catalyst] [debug] "My::App" defined "!default" as "CODE(0x83fd570)"
    You can connect to your server at http://localhost:3000

The server is now waiting for you to make requests of it. Try using telnet to manually make a simple GET request of the server (when telnet responds with "Escape character is '^]'.", type "GET / HTTP/1.0" and hit return twice):

    $ telnet localhost 3000
    Trying 127.0.0.1...
    Connected to localhost.
    Escape character is '^]'.
    GET / HTTP/1.0
    
    HTTP/1.0 200
    Server: Catalyst/4.26
    Status: 200
    Date: Sun, 20 Mar 2005 12:31:55 GMT
    X-catalyst: 4.26
    Content-length: 40
    Content-Type: text/html; charset=ISO-8859-1

    Congratulations, My::App is on Catalyst!
    Connection closed by foreign host.
    $

More trace messages will appear in the original terminal window:

    [Sun Mar 20 12:31:55 2005] [catalyst] [debug] ********************************
    [Sun Mar 20 12:31:55 2005] [catalyst] [debug] * Request 1 (0.027/s) [9818]
    [Sun Mar 20 12:31:55 2005] [catalyst] [debug] ********************************
    [Sun Mar 20 12:31:55 2005] [catalyst] [debug] "GET" request for ""
    [Sun Mar 20 12:31:55 2005] [catalyst] [debug] Using default action
    [Sun Mar 20 12:31:55 2005] [catalyst] [info] Processing "!default" took 0.000033s
    [Sun Mar 20 12:31:55 2005] [catalyst] [info] Request took 0.051399s (19.456/s)

The server will continue running until you interrupt it.

The application can also be tested from the command line using the generated helper script, script/test.pl.

Getting your application invoked

Catalyst applications are intended to be run from mod_perl, but can also be run as CGI scripts. Running under mod_perl gives better performance, but for development purposes you may want to run your application as a CGI script, especially as each changes to your application code take effect under CGI without having to restart the web server.

To run from mod_perl you need to add something like this to your Apache configuration file:

    <Location /myapp>
        SetHandler  perl-script
        PerlHandler MyApp
    </Location>

To run as a CGI script you need a wrapper script like:

    #!/usr/bin/perl -w

    use strict;
    use lib '/path/to/MyApp/lib';
    use MyApp;

    MyApp->run;

Catalyst outputs a complete HTTP response, which is not what is expected of a CGI script. You need to configure the script as a so-called "Non-parsed Headers" script for it to function properly. To do this in Apache just name the script starting with nph-.

Extending the generated code

The generated application code looks like this:

    package My::App;

    use strict;
    use Catalyst qw/-Debug/;

    our $VERSION = '0.01';

    My::App->config(
        name => 'My::App',
        root => '/home/andrew/My-App/root',
    );

    My::App->action(
        '!default' => sub {
            my ( $self, $c ) = @_;
            $c->res->output('Congratulations, My::App is on Catalyst!');
        },
    );

    1;

You can start extending the application by adding new actions:

    My::App->action(
        'test1' => sub {
            my ( $self, $c ) = @_;
            $c->res->output('In a new test action #1');
        },
        'test1' => sub {
            my ( $self, $c ) = @_;
            $c->res->output('In a new test action #1');
        },
        '!default' => sub {
            my ( $self, $c ) = @_;
            $c->res->output('Congratulations, My::App is on Catalyst!');
        },
    );

AUTHOR

Andrew Ford, A.Ford@ford-mason.co.uk

COPYRIGHT

This program is free software, you can redistribute it and/or modify it under the same terms as Perl itself.