是否在事务开始之前在Rails ActiveRecord中运行了一个回调？

Question

I just want to manipulate a model level object when it is newly created or it is updated. For example, consider there is a test table with name attribute:

class Test < ActiveRecord::Base
  custom_callback :hi
  def hi
    name = "h"
  end
end
m = Test.new(:name => "hello")
m.save

I just want to write a custom callback which should get executed before_validation and should get executed whenever a save or save! is called. Ideally, I want some callback in rails 2.3 which should get executed and hook into ActiveRecord::Base. is there any gem to do this or does anyone know how to write a callback which get executed before 'before_validation' callback?

Answer 1

You could override the save and save! methods to effectively inject the code. There's also the initialize method that might be appropriate depending on what you're trying to do. Also, before_validation runs before validate , so how much earlier do you need it to run exactly, and why?

Can you say more about why you want to do this? It sounds like you may have a design problem and you're trying to find a hack instead of addressing a more fundamental issue.

Answer 2

It seems you are looking for before_save, which runs after validation: http://api.rubyonrails.org/classes/ActiveRecord/Callbacks.html

Please refer to This answer