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

@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.