How can I create an association record if it does not exist when it is accessed?

Question

How would I do this pseudocode? I want to prevent for example "undefined method zip_code for nil class" as I have existing users with our a profile yet. So when user.profile is called I would like to create it if it does not exist.

class User < ActiveRecord::Base
...
  # Associations:
  has_one :profile


  # example call current_user.profile.zip_code
  def profile
    if self.profile exists <-- use super?
      self.profile
   else
     # create association record and return it
     self.build_profile.save
     self.profile
   end
  end
...
end

Answer 1

You could use after_initialize callback:

class User
  # ..
  after_initialize do
    self.profile ||= self.build_profile
  end
  # ..
end