What's the correct way to make before_validation, etc. work in an ActiveModel

问题

Should I extend or include ActiveModel:Validations:Callbacks:ClassMethods or ActiveModel:Validations:Callbacks?

回答1:

I got it to work like this:

class Foo
  extend ActiveModel::Callbacks
  include ActiveModel::Validations
  include ActiveModel::Validations::Callbacks

  before_validation :bar

  def bar
    # callback logic here
  end
end

It's important that you have everything in that order.

来源：https://stackoverflow.com/questions/8936906/whats-the-correct-way-to-make-before-validation-etc-work-in-an-activemodel