Rails 4 : has_many through association on an belongs_to polymorphic association

Question

I try to have a has_many through association on an belongs_to polymorphic association. For this I created, 3 class :

opinion.rb :

class Opinion < ActiveRecord::Base

  has_many :opinion_types
  has_many :name_applications, through: :opinion_types, source: :typeapplication, source_type: "NameApplication"

  accepts_nested_attributes_for :opinion_types
end

opinion_type.rb :

class OpinionType < ActiveRecord::Base

  belongs_to :opinion
  belongs_to :typeapplication, polymorphic: true

  accepts_nested_attributes_for :typeapplication
end

name_application.rb :

class NameApplication < ActiveRecord::Base

  has_one :opinion_type, as: :typeapplication
  has_one :opinion, through: :opinion_type
end

my OpinionsController :

class OpinionsController < ApplicationController

  def new
    @opinion = Opinion.new
    3.times do
      @opinion.name_applications << NameApplication.new
    end
  end

  def create
    @opinion = Opinion.new(params[opinions_params])
    @opinion.save

    redirect_to root_path
  end

private
  def opinions_params
    params.require(:opinion).permit(opinion_types_attributes: [name_applications: [:name]])
  end
end

my new.html.erb

<%= form_for @opinion do |o| %>
  <%= o.fields_for :opinion_types do |ot| %>
    <%= ot.fields_for :name_applications do |na| %>
      <%= na.label :name, "Name" %><br />
      <%= na.text_field :name %><br />
    <% end %>
  <% end %>
  <%= o.submit %>
<% end %>

After submitting the form with 3 names, I receive:

{"utf8"=>"✓",
 "authenticity_token"=>"blablabla",
 "opinion"=>{"opinion_types_attributes"=>{"0"=>{"name_applications"=>{"name"=>"name test"}},
 "1"=>{"name_applications"=>{"name"=>"name test 2"}},
 "2"=>{"name_applications"=>{"name"=>"name test 3"}}}},
 "commit"=>"Create Opinion"}

The problem is : I have a error unknown attribute: name_applications

When I write in Rails Console :

a = Opinion.new
a.name_applications << NameApplication.new(name: :"test")
a.name_applications << NameApplication.new(name: :"test 2")
a.name_applications << NameApplication.new(name: :"test 3")
a.save

My Opinion model and my NameApplication models associate to my Opinion model are correctly save.

I used different posts for try to find a solution but without succes :

I don't know if my problem is :

my accepts_nested_attributes_for :typeapplication in my opinion_type model (Because it a polymorphic association)
my strong parameters : params.require(:opinion).permit(opinion_types_attributes: [name_applications: [:name]])
or other

Thank you for your help

UPDATE : I find a solution but not very clean:

In my OpinionsController I changed my create action by this

  def create
    @opinion = Opinion.new
    opinions_params[:opinion_types_attributes].each do |f, index|
      @opinion.name_applications << NameApplication.new(opinions_params[:opinion_types_attributes][:"#{index}"][:name_applications])
    end

    @opinion.save

    redirect_to root_path
  end

I still do not understand why I can't just use @opinion = Opinion.new(opinions_params)

I will be grateful for any proposal that could help me to understand.

Rails 4 : has_many through association on an belongs_to polymorphic association

0 Answers0