Catalyst Advent - Day 9 - YAML, YAML, YAML!

NOTE: This article was written in 2005. In the meantime, Catalyst has switched to using Config::General as the format for its configuration files. YAML files being whitespace-sensitive, copy/pasting from POD often caused problems. See also the Catalyst Wiki (

When you start a new Catalyst app you configure it directly with __PACKAGE__->config, thats ok for development but admins will hate you when they have to deploy this.

    __PACKAGE__->config( name => 'MyApp', 'View::TT' => { EVAL_PERL => 1 } );

You didn't know you could configure your view from the application class, eh? :) Thats possible for every component that inherits from Catalyst::Component or it's subclasses (Catalyst::Base, Catalyst::Controller, Catalyst::View, Catalyst::Model).

        name => 'MyApp',
        'View::TT' => {
            EVAL_PERL => 1
        'Controller::Foo' => {
            fool => 'sri'


    package MyApp::Controller::Foo;
    use base 'Catalyst::Controller';

    __PACKAGE__->config( lalala => " can't sing!" );

    sub default : Private {
        my ( $self, $c ) = @_;
        $c->res->body( $self->{fool} . $self->{lalala} );

But back to the topic, lets make our admins happy with this little idiom.

    use YAML ();

    __PACKAGE__->config( YAML::LoadFile( __PACKAGE__->path_to('myapp.yml') ) );

The path_to() method is a nice little helper that returns paths relative to the current application home.

Thats it, now just create a file myapp.yml.

    name: MyApp
      EVAL_PERL: 1
      fool: sri

Have fun!

-- sri