权限和角色存储在 DB、rails 3.1 中

Question

在我的应用程序中，我想以这样的方式实现角色和权限，以便用户管理员可以在他们的浏览器中创建新角色。所以我需要权限表和角色表，其中每个角色都是权限的组合。现在我使用 CanCan gem，但这种行为不是这个 gem 的默认行为，最后我得到了非常复杂的角色结构和检查权限。谁能告诉我什么宝石提供了这种行为，或者也许我应该在没有任何宝石的情况下实现它？

Answer 1

请参阅数据库中的功能和来自 CanCan wiki 的其他用户的能力：

class Ability
  include CanCan::Ability

  def initialize(user)
    can do |action, subject_class, subject|
      user.permissions.find_all_by_action(aliases_for_action(action)).any? do |permission|
        permission.subject_class == subject_class.to_s &&
          (subject.nil? || permission.subject_id.nil? || permission.subject_id == subject.id)
      end
    end
  end
end

编辑
一些负载优化：

class Ability
  include CanCan::Ability

  def initialize(user, context = nil)
    if context.nil?
      can do |action, subject_class, subject|
        user.permissions.find_all_by_action(aliases_for_action(action)).any? do |permission|
          permission.subject_class == subject_class.to_s &&
           (subject.nil? || permission.subject_id.nil? || permission.subject_id == subject.id)
      end
    elsif context == :post
      can :manage, Post, :id => y
    elsif context == :users
      can :manage, User, :id => x
    end
  ...

在控制器中：

class UsersController
  protected
  def current_ability
    Ability.new(current_user, :users)

class PostsController
  protected
  def current_ability
    Ability.new(current_user, :posts)