Question

I’ve got the following (sanitized) models:

 class Person < ActiveRecord::Base

      attr_accessible :name, :first_name, :last_name, :age, :job_title, :salary, :ssn, :prison_convictions, :addresses_attributes

      has_many :addresses, inverse_of: :person

      accepts_nested_attributes_for :addresses, allow_destroy: true

 end



 class Address < ActiveRecord::Base

      attr_accessible :zip_code, :street,:house_number,
 :unique_per_person_government_id

      belongs_to :person, inverse_of: :addresses

      validates_uniqueness_of :unique_per_person_government_id, scope: :person_id
 end

The problem is as follows,

Lets say Person Joe Shmoe has two addresses currently attached to himself

666 Foo Street, 12345 with unique id: “ABCDEFG”
and
777 Lucky Avenue, 54321 with unique id: “GFEDCBA”

And lets say that the following post comes through from a form:

 {:addresses_attributes =>
 { [0] => {:unique_per_person_government_id => “ABCDEFG”, :street=> “Foo Street”, :house_number => 666, :zip_code=>12345, _destroy => 1}
 [1] => {:unique_per_person_government_id => “ABCDEFG”, :street=>”Bar Street”, :house_number => 888, :zip_code => 12345, _destroy => 0}
 }

The behavior appears to be that the second (ie the new) record is validated for uniqueness first, failing validation.

The behavior I would like is to quite simply remove all elements that are marked_for_destruction? before conducting any further validation.

How can I rewire the lifecycle in this way? Is there a better way to achieve this?

Thanks!

Answer 1

I’ve solved this as follows:

class Person < ActiveRecord::Base
  attr_accessible :name, :first_name, :last_name, :age, :job_title, :salary, :ssn, :prison_convictions, :addresses_attributes

  has_many :addresses, inverse_of: :person

  accepts_nested_attributes_for :addresses, allow_destroy: true

  def validate_addresses
    codes = {}
    addresses.each do |a|
      if codes.key?(a.unique_per_person_government_id) and not a.marked_for_destruction?
        codes[a.unique_per_person_government_id] = codes[a.unique_per_person_government_id]+1
        if codes[a.unique_per_person_government_id] > 1
          return false
        end
      elsif not codes.key?(a.unique_per_person_government_id) and a.marked_for_destruction?
        codes[a.code] = 0
      elsif not codes.key?(a.unique_per_person_government_id) and not a.marked_for_destruction?
        codes[dacode] = 1
      end
    end
    return true
  end
end


class Address < ActiveRecord::Base
  before_save :validate_addresses

  attr_accessible :zip_code, :street,:house_number, :unique_per_person_government_id

  belongs_to :person, inverse_of: :addresses

  validates_uniqueness_of :unique_per_person_government_id, scope: :person_id, unless: :skip_validation?

  def skip_validation?
    person.addresses.each do |a|
      if unique_per_person_government_id == a.code and id != a.id
        return false unless a.marked_for_destruction?
      elsif id == a.id and a.marked_for_destruction?
        return false
      end
    end
    return true
  end
end

Thus enforcing uniqueness, and preventing a person with invalid addresses from saving, but ignoring items that are marked for destruction. If anybody has had a similiar problem and has a better/algorithmically simpler/easier to read solution, and would like to share it, that would be awesome 😀