使用模块使用"has_many"扩展插件中的模型

Question

我在引擎样式插件中有一些代码,其中包含一些模型.在我的应用程序中,我想扩展其中一个模型.我已经设法通过在初始化程序中包含一个模块,将实例和类方法添加到相关模型中.

但是,我似乎无法添加关联,回调等.我得到'找不到方法'错误.

/libs/qwerty/core.rb

module Qwerty
  module Core
    module Extensions

      module User
        # Instance Methods Go Here 

        # Class Methods
        module ClassMethods
          has_many  :hits, :uniq => true # no method found

          before_validation_on_create :generate_code # no method found

          def something # works!
            "something"
          end
        end

        def self.included(base)
          base.extend(ClassMethods)
        end
      end
    end
  end
end

/initializers/qwerty.rb

require 'qwerty/core/user'

User.send :include, Qwerty::Core::Extensions::User

Answer 1

你应该能够做到这一点.更简洁恕我直言.

module Qwerty::Core::Extensions::User
  def self.included(base)
    base.class_eval do
      has_many  :hits, :uniq => true
      before_validation_on_create :generate_code
    end
  end
end

Answer 2

我认为这应该有效

module Qwerty
  module Core
    module Extensions
      module User
      # Instance Methods Go Here 

        # Class Methods
        module ClassMethods
          def relate
            has_many  :hits, :uniq => true # no method found

            before_validation_on_create :generate_code # no method found
          end

          def something # works!
            "something"
          end
        end

        def self.included(base)
          base.extend(ClassMethods).relate
        end
      end
    end
  end
end

旧代码是错误的,因为验证和关联是在模块加载时调用的,并且此模块对ActiveRecord一无所知.这是Ruby的一般方面,类或模块体内的代码在加载时直接调用.你不希望这样.要解决这个问题,您可以使用上述解决方案.

Answer 3

在Rails 3中,这听起来像ActiveSupport :: Concern的一个很好的用例:

module Qwerty::Core::Extensions::User

  extend ActiveSupport::Concern

  included do
    has_many  :hits, :uniq => true
    before_validation_on_create :generate_code 
  end
end

class User
  include Querty::Core::Extensions::User
  # ...
end

以下是我发现的ActiveSupport :: Concern文档和最有用的博客文章.