Unpermitted parameters for double-nested models in Rails 4

Question

I\'m new to Rails and built something based on this, but it needed small updates to make it compatible with Rails 4\'s strong parameters:

http://railscasts.com/episo

Answer 1

I found out the fix is that the whitelist needs to match the nesting of attributes. So to fix the above I changed this:

class SurveysController < ApplicationController
  def survey_params
    params.require(:survey).permit(:name, questions_attributes: [:id, :survey_id,    :content])
  end

to this:

class SurveysController < ApplicationController
  def survey_params
    params.require(:survey).permit(:name, questions_attributes: [:id, :survey_id,    :content, answers_attributes: [:id, :question_id, :content]])
  end

E.g. simply copy the whitelist of the answers_attributes and insert it inside before the closing "]" for the questions_attributes.

Hopefully this will help others with the same problem.