ruby-on-rails - Rails，类中未定义的方法但存在方法

Question

我正在尝试解决一个奇怪的问题。我正在使用模块扩展 ActiveRecord。

module StringyAssociationIds

  def stringy_ids(association)
    define_method("stringy_#{association}_ids=") do |comma_seperated_ids|
      self.send("#{association}_ids=", comma_seperated_ids.to_s.split(","))
    end

    define_method("stringy_#{association}_ids") do
      send("#{association}_ids").join(",")
    end
  end

end

ActiveRecord::Base.extend(StringyAssociationIds) 

我有一个类“门”，我有一个关联。

class Gate < ActiveRecord::Base
  include Productable
  stringy_ids :product
end

关联是用连接表定义的:

module Productable
  extend ActiveSupport::Concern

  included do
    has_many :productable_products, as: :productable
    has_many :products, through: :productable_products
  end

end

当我尝试创建一个新门时出现错误:

undefined method `stringy_ids' for #<Class:0x007f91e12bb7e8>

我的错在哪里？

编辑:我也尝试在 lib 目录中添加一个扩展(由 application.rb 自动加载)

module ActiveRecordExtension

  extend ActiveSupport::Concern

  def stringy_ids(association)
    define_method("stringy_#{association}_ids=") do |comma_seperated_ids|
      self.send("#{association}_ids=", comma_seperated_ids.to_s.split(","))
    end

    define_method("stringy_#{association}_ids") do
      send("#{association}_ids").join(",")
    end
  end

end

# include the extension 
ActiveRecord::Base.send(:include, ActiveRecordExtension)

我也在控制台中尝试:

ActiveRecordExtension.instance_methods
 => [:stringy_ids]

所以我的扩展程序已加载...

Answer 1

您的类方法 stringy_ids 是在 ActiveRecord::Base 上定义的，而不是 Gate。与实例方法不同，类方法不被继承，因为 Gate 单例类不是 ActiveRecord::Base 单例类的子类。