Relationships with ActiveModelSerializers::Model

[andrewferk]

I'm using version 0.10.2 and attempting to create a relationship (belongs_to) with ActiveModelSerializers::Model (and not ActiveRecord::Model). The relationship output keeps returning null.

Thanks!

Model

class User::Registration < ActiveModelSerializers::Model

  attr_reader :user
  attr_accessor :email

  def save
    register_user
  end

  def email=(value)
    # Follow Devise's configuration to check if email is case insensitive
    @email = Devise.case_insensitive_keys.include?(:email) ? value.try(:downcase) : value
  end

  def id
    email
  end

  private

  def register_user
    @user = User.new(email: email)
    @user.provider = 'email'

    @user.send_confirmation_instructions if @user.save
    @user.clean_up_passwords

    @user.persisted?
  end
end

Resource

class User::RegistrationSerializer < ApplicationSerializer
  attributes :email
  belongs_to :user
end

Controller

def create
  @registration = User::Registration.new(email: @request[:email])
  @registration.save
  render json: @registration, status: :created
end

Ouptut

{"data": {"id":"a@b.co","type":"user-registrations","attributes":{"email":"a@b.co"},"relationships":{"user":{"data":null}}}}

I'd expect the relationships output to not be null.

[beauby]

What is the output of @registration.user before the save call?

[andrewferk]

What is the output of @registration.user before the save call?

It is nil.

It looks like I'm having problems with ActiveModelSerializers::Model as it sets @attributes in the initializers and uses it for serialization. That doesn't work for me because I'm setting the user using @user.

My model has been updated to the following:

class User::Registration < ActiveModelSerializers::Model
  include ActiveModel::Model
  include ActiveModel::Serialization
end

ActiveModel::Serialization sets alias :read_attribute_for_serialization :send.

[beauby]

As far as I can tell, you're not setting the user, so I do not understand why it would be surprising that the user is nil in the serialized document?

[andrewferk]

It's set in the User::Registration#register_user method.

[beauby]

As far as I can tell it is never called though.

[beauby]

Oops – it is indeed called in the save method.

[beauby]

What is the value of @registration.user after the save call?

[andrewferk]

It's a User, and it did save successfully. I think the change I did will allow this to work, although I haven't gotten around to checking yet.

[groyoh]

I guess this is related to #1953. @andrewferk you are right in #1961 (comment). When @user = ... is set, the @attributes value is not actually changed and @attributes is the value used for serializing the object (ref). That's an issue with the AMS::Model class itself. As mentioned in #1953 I'm not entirely aware of the purpose of AMS::Model and if it's really meant to be used outside AMS. @beauby what's your thoughts about that?

[bf4]

@andrewferk This is a known bug in AMS::Model that no one has fixed yet. see #1903 until it is fixed, you can either roll your own poro, using AMS::Model as a reference doc (which is part of its intention), or call attributes[:user] = self.user = User.new(email: email) instead of self.user = User.new(email: email) :(

[bf4]

Looks like I've implemented a good chunk of this in #1984

[axsuul]

@bf4 Sorry, I did some digging but still not quite sure if this has been fixed or not by your pull request

[bf4]

Also see

active_model_serializers/test/fixtures/poro.rb

Lines 6 to 26 in 3c5e11b

	# At this time, just for organization of intent
	class_attribute :association_names
	self.association_names = []
	def self.associations(*names)
	self.association_names |= names.map(&:to_sym)
	# Silence redefinition of methods warnings
	ActiveModelSerializers.silence_warnings do
	attr_accessor(*names)
	end
	end
	def associations
	association_names.each_with_object({}) do |association_name, result|
	result[association_name] = public_send(association_name).freeze
	end.with_indifferent_access.freeze
	end
	def attributes
	super.except(*association_names)
	end