how to run code when embedded document is created

Question

I have the following models:

class User
  include Mongoid::Document

  embeds_one :courier, class_name: "Users::Courier"
  validates_associated :courier
  accepts_nested_attributes_for :courier
end

module Users
  class Courier
    include Mongoid::Document

    embedded_in :user
    after_create :foo

    def foo
        puts "courier created"
    end
end

but this callback is only run if i call save directly on the courier object, not when i save the parent object.

Thus having a nested form and a controller that creates the user including the courier does not run the create callback of the courier.

The mongoid documentation says that this is by design:

Callbacks are available on any document, whether it is embedded within another document or not. Note that to be efficient, Mongoid only fires the callback of the document that the persistence action was executed on. This is that Mongoid aims to support large hierarchies and to handle optimized atomic updates callbacks can't be firing all over the document hierarchy.

But how can i write code that gets executed whenever a courier is created? In my case i cannot run the code in the user's after_create callback, because there are users that do not have the embedded document courier. But when a courier gets added i want to run a callback.

Whats the best option to do so?

Answer 1

found the answer:

embeds_one :courier, class_name: "Users::Courier", cascade_callbacks: true