ruby-on-rails - 使用 mixins 初始化类变量

Question

我有

class Fruit < ActiveRecord::Base
    includes Skin
end

和mixin模块

module Skin
    def initialize
        self.skin = "fuzzy"
    end
end

我想要这样

>> Fruit.new
#<Fruit skin: "fuzzy", created_at: nil, updated_at: nil>

Answer 1

使用 ActiveRecord after_initialize 回调。

module Skin
  def self.included(base)
     base.after_initialize :skin_init
  end

  def skin_init
    self.skin = ...
  end
end

class Fruit < AR::Base
  include Skin
  ...
end