Creating a collection of nested resources in roar-rails

Question

I am trying to create new objects with a collection of nested resources. When I POST my json, I get:

ActiveRecord::AssociationTypeMismatch: FormLabel(#70306552439440) expected, got Hash(#70306480154920)

Here's my code:

# form.rb
class Form < ActiveRecord::Base
  has_many :form_labels
  validates_presence_of :name
end

# form_label.rb
class FormLabel < ActiveRecord::Base
  belongs_to :form
  validates_presence_of :form
  validates_presence_of :text
end

# form_representer.rb
module FormRepresenter
  include Roar::JSON
  property :id
  property :name
  collection :form_labels
end

# form_label_representer.rb
module FormLabelRepresenter
  include Roar::JSON
  property :text  
end

# form_controller.rb
class FormsController < ApplicationController
  include Roar::Rails::ControllerAdditions
  def create
    form = Form.new
    consume!(form)
    respond_with(form)
  end

When I debug, these are the params:

0> params
=> {"name"=>"Address", "form_labels"=>[{"text"=>"foo"}], "format"=>"json", "controller"=>"forms", "action"=>"create", "form"=>{"name"=>"Address"}}

and the error is:

ActiveRecord::AssociationTypeMismatch: FormLabel(#70237358584300) expected, got Hash(#70237286721880)

Answer 1

The error is in the line:

collection :form_labels

It needs to be:

collection :form_labels, decorator: FormLabelRepresenter, class: FormLabel

See https://github.com/apotonick/roar-rails/issues/125#issuecomment-172175231