Ruby元编程-使用Before/After回调和aliasu方法对方法进行子类化

Posted 2021-02-25

require 'rubygems'
require 'active_model'
 
class BaseModel
  extend ActiveModel::Callbacks
 
  define_model_callbacks :save
  before_save { puts "[save:before]"}
  after_save { puts "[save:after]"}
 
  def do_save; end
  def save
    _run_save_callbacks do
      do_save
    end
  end
  alias_method :superclass_save, :save
end
 
class SomeModel < BaseModel
  def save
    puts "[saving...]"
    true
  end
end
 
SomeModel.class_eval do
  alias_method :subclass_save, :save
  alias_method :do_save, :subclass_save
  alias_method :save, :superclass_save
end
 
model = SomeModel.new
model.save