对于Rails问题,我可以通过包含它们来通过模块提供我的模型类方法和实例方法.我发现没有博客条目或帖子提到我如何在我的模型中包含变量.
具体来说,我想给我的包含模型一个类实例变量@question,但我不知道在模块中将声明放在何处以便应用它.如果模型本身声明该变量,我还希望覆盖类实例变量.
ActiveSupport :: Concern模块是否真的关心变量？
- module ContentAttribute
- extend ActiveSupport::Concern
- def foo
- p "hi"
- end
- module ClassMethods
- # @question = "I am a generic question." [doesn't work]
- def bar
- p "yo"
- end
- end
- end
- class Video < ActiveRecord::Base
- include ContentAttribute
- # @question = "Specific question"; [should override the generic question]
- end
解决方法
- module ContentAttribute
- extend ActiveSupport::Concern
- included do
- self.question = "I am a generic question."
- end
- module ClassMethods
- attr_accessor :question
- end
- end
那么,在视频中……
- class Video < ActiveRecord::Base
- include ContentAttribute
- self.question = "Specific question"
- end