覆蓋類和實例方法的method_missing？

Question

我正在嘗試編寫一個通用模塊，將dynamic_missing模式應用於我的一些Rails模型中。 這些模型具有類方法和實例方法。 雖然我可以相當直接地為類案例編寫一個模塊：

  module ClassVersion
    extend ActiveSupport::Concern

    module ClassMethods
      def method_missing(meth, *args, &block)
        if meth.to_s =~ /^(.+)_async$/
          Async::handle_async self, $1, *args, &block
        else
          super meth, *args, &block
        end
      end

      # Logic for this method MUST match that of the detection in method_missing
      def respond_to_missing?(method_name, include_private = false)
        Async::async?(method_name) || super
      end
    end
  end

或實例案例：

  module InstanceVersion
    extend ActiveSupport::Concern

    def method_missing(meth, *args, &block)
      if meth.to_s =~ /^(.+)_async$/
        Async::handle_async self, $1, *args, &block
      else
        super meth, *args, &block
      end
    end

    # Logic for this method MUST match that of the detection in method_missing
    def respond_to_missing?(method_name, include_private = false)
      Async::async?(method_name) || super
    end
  end

......我似乎無法在同一個班級支持這兩種情況。 有沒有更好的方法來覆蓋method_missing，以便支持這兩種情況？ 我在Rails 3.2上....

Answer 1

你想要達到的目標非常簡單，同時又不同尋常。 ActiveSupport::Concern讓您可以定義嵌套的ClassMethods模塊，該模塊在included模塊掛鈎上擴展基類。 通常這很方便，因為您不希望使用相同的方法擴充類及其實例。

您需要做的是停止使用ActiveSupport::Concern並編寫included鈎子以滿足您的特定需求：

module AsyncModule
  def method_missing(meth, *args, &block)
    if meth.to_s =~ /^(.+)_async$/
      Async::handle_async self, $1, *args, &block
    else
      super meth, *args, &block
    end
  end

  # Logic for this method MUST match that of the detection in method_missing
  def respond_to_missing?(method_name, include_private = false)
    Async::async?(method_name) || super
  end

  private

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

Answer 2

你試過以下嗎？

  module ClassAndInstanceVersion
    extend ActiveSupport::Concern

    def method_missing(meth, *args, &block)
      self.class.method_missing(meth, *args, &block)
    end

    def respond_to_missing?(method_name, include_private = false)
      self.class.respond_to_missing?(method_name, include_private)
    end

    module ClassMethods
      def method_missing(meth, *args, &block)
        if meth.to_s =~ /^(.+)_async$/
          Async::handle_async self, $1, *args, &block
        else
          super meth, *args, &block
        end
      end

      # Logic for this method MUST match that of the detection in method_missing
      def respond_to_missing?(method_name, include_private = false)
        Async::async?(method_name) || super
      end
    end
  end