Re: RFC: Apache::Controller

[sri]

Funny, this looks a bit similar to a project i'll release very soon called Catalyst.

I started the project while i maintained Maypole, it was supposed to fix some design flaws and become Maypole 3.0.

But it has fast grown into something very different from Maypole, so it became a subproject which now completely aims at enterprise class applications.

There are still lots of features from Maypole present but i also added many things from Struts, Struts-Chain, Struts-Delegate(Action mapping, Chain of Responsibility, Forms, Decorators, Filters), Tomcat(Contexts, Sessions, elegant api for headers, cookies and uploads...), SpringMVC(AOP features...), Ruby on Rails (Multiple controller support) and WebWork2.

Stuff like exception handling, roles based security, i18n, mod_perl1/mod_perl2/CGI support with unified api, simple debugging and profiling is naturally built in.

It also has many benefits for development in big teams and refactoring. (separation of flow and code, splitting code into small pieces...)

Here is an example for a Controller class.

package PetStore;

use strict;
use Catalyst '-Debug';

# Application name
PetStore->config->name('Catalyst PetStore');

# Root directory for additional files
PetStore->config->root('/home/sri/PetStore/web');

# Base uri for our application
PetStore->config->base('http://localhost/petstore');

# Session settings
PetStore->config->session(
    class   => 'Apache::Session::Postgres',
    options => {
        DataSource => 'dbi:Pg:dbname=petstore',
        TableName  => 'session',
        UserName   => 'postgres',
        Password   => 0,
        Commit     => 1
    }
);

# Actions
PetStore->action(


    # Built in action that'll get called at the end of a request,

    # we use it for the view here,
    # which in this case is YAML REST or TT2
    _end => sub {

        # form() returns a Data::FormValidator::Results object that
        # will be automatically initialised when you use it
        if ( form->valid('rest') ) {

            # trunk is our universal data container to exchange
            # informations between actions and methods
            trunk( content_type => 'text/plain' );
            call('PetStore::View::REST');
        }
        else {

            # Set a default template
            trunk( template => 'index.tt' );
            call('PetStore::View::TT');
        }
    },
    # Built in action that'll get called once at startup time to
    # initialze your environment
    '_setup' => sub {

        # setup initializes a Catalyst component for you
        setup('PetStore::Model::Cart');
        setup(
            'PetStore::Model::CDBI',
            base     => 'Catalyst::Model::CDBI',
            dsn      => 'dbi:Pg:dbname=petstore',
            user     => 'postgres',
            password => '',
            options  => { AutoCommit => 1 }
        );
        setup( 'PetStore::View::REST',
          base => 'Catalyst::View::REST::YAML' );
        setup( 'PetStore::View::TT',   base => 'Catalyst::View::TT' );
    },

    # Private action to publish the cart
    _cart_to_objects => sub {
        call(qw(PetStore::Model::Cart items_to_objects));
        call(qw(PetStore::Model::CDBI::Item describe_cart_items));

        call(qw(PetStore::Model::CDBI::Category describe_cart_items));
    },

    # Private action to to publish categories
    _categories_to_objects => sub {

        call(qw(PetStore::Model::CDBI::Category list));
    },

    # Start page
    'index.html' => sub {
        trunk( template => 'index.tt' );

        # Merge with the existing Data::FormValidator::Results object
        # or create a new one
        form( required => ['yada'] );

        # Include a private action at this point
        include('_categories_to_objects');
    },

    # Show and edit the cart
    'cart.html' => sub {
        trunk( template => 'cart.tt' );
        call(qw(PetStore::Model::Cart add))    if form->valid('add');
        call(qw(PetStore::Model::Cart update))
          if form->valid('update');
        include('_cart_to_objects');
    },

    # Show products in category
    'category.html' => sub {
        roles(qw(foo bar));
        trunk( template => 'category.tt' );
        call(qw(PetStore::Controller::CDBI::Product list));
    }
);

1;

The code is almost done and i'm currently writing documentation and examples for it, so if you're interested just hang out at #maypole on irc.perl.org (i'm searching testers;) or wait for the release, which will happen soon.

[revdiablo]

Funny, this looks a bit similar to a project i'll release very soon called Catalyst.

Only if you would say a jetliner is "a bit similar" to a hang glider. :-) I must say, your project is much more ambitious than mine. I was attempting to be one humble piece of a very small pie, but what you have seems to be an entire pie with ice cream and chocolate sauce on the side. [Hmm, what other strained metaphors can I come up with?]

What you've shown looks very nice, and it would probably save a lot of time and effort in a large project, but for some projects it would be major overkill. I was trying to build the module that's useful for the smaller projects. It works well with the small, extremely simple application that I'm building, and attempts to follow the "do one thing and do it well" philosophy.

The problem is, I don't know if the small, simple solution would really be useful for anyone else. Based on the replies to this Meditation, the answer is "nah, we're happy with what we've already got." So I'll avoid releasing it unless someone asks.