ruby-on-rails - 如何在插件的 before_save 回调中包含实例方法？

Question

我正在创建一个插件，但很难定义调用我刚刚定义的实例方法的 before_save 过滤器。这是一个快速示例:

module ValidatesAndFormatsPhones
  def self.included(base)
    base.send :extend, ClassMethods
  end

  module ClassMethods

    def validates_and_formats_phones(field_names = [:phone])
      send :include, InstanceMethods

      # the following variations on calls to :format_phone_fields fail

      before_save send(:format_phone_fields, field_names)

      before_save format_phone_fields(field_names)

      before_save lambda { send(:format_phone_fields, field_names) }

      # EACH OF THE ABOVE RETURNS 'undefined_method :format_phone_fields'
    end
  end

  module InstanceMethods

    def format_phone_fields(fields = [:phone], *args)
      do stuff...
    end

  end
end

ActiveRecord::Base.send :include, ValidatesAndFormatsPhones

我想问题是，如何将上下文更改为实例而不是类？

我更喜欢调用实例方法，因为该类实际上不应该有一个名为“format_phone_fields”的方法，但实例应该有。

谢谢!

Answer 1

在适当的时候包含您的方法:当您扩展基类时:

module ValidatesAndFormatsPhones
  def self.included(base)
    base.send :extend, ClassMethods
    base.send :include, InstanceMethods
  end

  module ClassMethods
    def validates_and_formats_phones(field_names = [:phone])
      before_save {|r| r.format_phone_fields(field_names)}
    end
  end

  module InstanceMethods
    def format_phone_fields(fields = [:phone], *args)
      # do stuff...
    end
  end
end

ActiveRecord::Base.send :include, ValidatesAndFormatsPhones

我还没有运行代码，但它应该可以工作。我经常做类似的事情。