Wtf cancan?

ability.rb

# Article is a normal AR class, no methods, just attributes. free is a boolean attribute.
# 
# /articles/1 is free, /articles/2 is not. 
# 
# I want only logged in users to read non-free articles. But the :free => true line seems to be enabling 
# reading all of them; when I comment it out, non-logged-in users can't read anything. But with it
# uncommented, they can read everything. WTF?
#
# User.new.is? :user is false, and so is User.new.is? :admin.

class Ability
  include CanCan::Ability

  def initialize(user)
    user ||= User.new

    if user.is? :user
      can :show, Article
    elsif user.is? :admin
      can [:show, :create, :update], Article
    else
      can :show, Article, :free => true
      cannot :show, Article, :free => false
    end
  end
end

article_repository.rb

class ArticleRepository
  class << self
    delegate :find, :new, :to => Article

    def root
      Article.first
    end
  end
end

articles_controller.rb

class ArticlesController < ApplicationController
  def new
    @article = ArticleRepository.new
  end

  def create
    @article = ArticleRepository.new params[:article]
    @article.update_attributes(params[:article])
    @article.save
    redirect_to article_path(@article)
  end

  def show
    #begin
      @article = ArticleRepository.find(params[:id])
      authorize!(:show, @article)

    #rescue ActiveRecord::RecordNotFound
    #  render :create
    #  return
    #end
  end

user.rb

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :token_authenticatable, :encryptable, :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  # Setup accessible (or protected) attributes for your model
  attr_accessible :email, :password, :password_confirmation, :remember_me

  include RoleModel
  roles :admin, :user
end

@steveklabnik, i've been thinking about why use the repository pattern instead of access directly into ActiveRecord? http://martinfowler.com/eaaCatalog/repository.html it says that repository is about to mediate the domain and data mapping layer(active record in this case). but in practice what are the benefits of using this? thank you.

@guilherme ... pay attention to my blog sometime next week.

@steveklanik i'm curious about it .. i can't wait until next week. :( :~

Here's the one sentence answer: It decreases the coupling in your code.