Rails after_initialize only on "new"

Question

I have the following 2 models

class Sport < ActiveRecord::Base   has_many :charts, order: "sortWeight ASC"   has_one :product, :as => :productable   accepts_nested_attributes_for :product, :allow_destroy => true end  class Product < ActiveRecord::Base   belongs_to :category   belongs_to :productable, :polymorphic => true end 

A sport can't exist without the product, so in my sports_controller.rb I had:

def new   @sport = Sport.new   @sport.product = Product.new ... end 

I tried to move the creation of the product to the sport model, using after_initialize:

after_initialize :create_product  def create_product  self.product = Product.new end 

I quickly learned that after_initialize is called whenever a model is instantiated (i.e., from a find call). So that wasn't the behavior I was looking for.

Whats the way I should be modeling the requirement that all sport have a product?

Thanks

Answer 1

Putting the logic in the controller could be the best answer as you stated, but you could get the after_initialize to work by doing the following:

after_initialize :add_product  def add_product   self.product ||= Product.new end 

That way, it only sets product if no product exists. It may not be worth the overhead and/or be less clear than having the logic in the controller.

Edit: Per Ryan's answer, performance-wise the following would likely be better:

after_initialize :add_product  def add_product   self.product ||= Product.new if self.new_record? end 

Answer 2

Surely after_initialize :add_product, if: :new_record? is the cleanest way here.

Keep the conditional out of the add_product function