rails4中的多態關聯

Question

我正在關注本教程http://blog.endpoint.com/2012/01/ruby-on-rails-rights-attributes.html以爲我的rails4應用程序設置授權機制。

我已經創建了數據模型，但不管理（從控制檯）獲取用戶的權限（通過all_rights方法）。

在用戶模型中，User對象如何通過RightAssignment調用「self.rights」權限，而不是直接來自User？

我的模型：

class User < ActiveRecord::Base 
    has_many :right_assignments, as: :subject 
    has_and_belongs_to_many :groups 
    has_and_belongs_to_many :roles 

    def all_rights 
    rights = [self.rights + 
      self.groups.collect { |g| g.allowed_rights } + 
      self.roles.collect { |r| r.rights }] 
    rights = rights.flatten.uniq.collect { |r| r.action } 
    rights 
    end 
end 

class Group < ActiveRecord::Base 
    has_many :right_assignments, as: :subject 
    has_and_belongs_to_many :users 

    def allowed_rights 
    self.assignable_rights ? self.rights : [] 
    end 
end 

class Role < ActiveRecord::Base 
    has_many :right_assignments, as: :subject 
    has_and_belongs_to_many :users 
end 

class RightAssignment < ActiveRecord::Base 
    belongs_to :right 
    belongs_to :subject, polymorphic: true 
end 

class Right < ActiveRecord::Base 
    has_many :right_assignments 
end 

任何想法？

Answer 1

可以使用:through

class User < ActiveRecord::Base 
    has_many :right_assignments, as: :subject 
    has_many :rights, :through => :right_assignments 
    has_and_belongs_to_many :groups 
    has_and_belongs_to_many :roles