未初始化的常量ActiveSupport ::关注

Question

我得到以下链接来解决与类和实例方法相关的问题。 http://www.fakingfantastic.com/2010/09/20/concerning-yourself-with-active-support-concern/

module NotificationsHelper
  extend ActiveSupport::Concern

  module ClassMethods
    def my_class_method
      # ...
    end
  end

  module InstanceMethods
    def my_instance_method
      # ...
    end
  end
end

但是我得到未初始化的常量ActiveSupport :: Concern 错误。我正在使用Rails 2.3.5和Ruby 1.9.2p180

Answer 1

此模块仅适用于Rails 3以后