Question

My app has three models:

Thread (has_many :thread_apps)
ThreadApp (belongs_to :thread, has_many :forms, :as => :appable)
Form (belongs_to :app)

ThreadApp Fields: thread_id, form_id, appable_id, appable_type

What I want to be able to do is when creating a form, ensure that a ThreadApp record is also created to make the association:

Here is what I have:

class FormsController < ApplicationController

 def create
    @thread = Thread.find(params[:thread_id])
    @thread_app = @thread.thread_apps.new
    @form = @thread_app.forms.build(params[:form].merge(:user_id => current_user.id))
    @form.save
    ....

This is saving the form nicely, but the thread_app associated is not being made? Any ideas why?

Thank you

Answer 1

callings model.save does not save associations unless you tell it to

you can set autosave

class Form < ActiveRecord::Base
   belongs_to :thread_app , :autosave => true
end

or call save on it in the controller

@thread_app.save

or you can take it out of the controller entirely
and do this with a callback

class Form < ActiveRecord::Base
   before_create :create_thread_app
   def create_thread_app
     self.thread_app ||= ThreadApp.create(...)
   end
end

or after_create, _before_validation_on_create, or any other call back would work

—UPDATE—

this might make a difference using create inse=tead of new, and appables that you specified as ‘as’

class FormsController < ApplicationController

 def create
    @thread = Thread.find(params[:thread_id])
    @thread_app = @thread.thread_apps.create
    @form = @thread_app.appables.build(params[:form].merge(:user_id => current_user.id))
    @form.save
    ....