Unpermitted parameters & unable to display nested fields_for - ruby-on-rails

Question

I am building simple ROR app which has survey question and answers. Survey is generated using scaffolding method while question and answer are model only.
Survey.rb
class Survey < ApplicationRecord
has_many :questions
accepts_nested_attributes_for :questions, allow_destroy: true
validates :name, presence: true
end
Question.rb
class Question < ApplicationRecord
belongs_to :survey
has_many :answers
accepts_nested_attributes_for :answers
validates :question_content, presence: true
end
Answer.rb
class Answer < ApplicationRecord
belongs_to :question
end
survey_controller.rb
class SurveysController < ApplicationController
before_action :set_survey, only: [:show, :edit, :update, :destroy]
def index
#surveys = Survey.all
end
def show
#survey= Survey.find(params[:id])
end
def new
#survey = Survey.new
#questions = #survey.questions.new
#answers = #questions.answers.new
end
def edit
end
def create
#survey = Survey.new(survey_params)
Survey.create(survey_params)
respond_to do |format|
if #survey.save
format.html { redirect_to #survey, notice: 'Survey was successfully created.' }
format.json { render :show, status: :created, location: #survey }
else
format.html { render :new }
format.json { render json: #survey.errors, status: :unprocessable_entity }
end
end
end
def update
respond_to do |format|
if #survey.update(survey_params)
format.html { redirect_to #survey, notice: 'Survey was successfully updated.' }
format.json { render :show, status: :ok, location: #survey }
else
format.html { render :edit }
format.json { render json: #survey.errors, status: :unprocessable_entity }
end
end
end
def destroy
#survey.destroy
respond_to do |format|
format.html { redirect_to surveys_url, notice: 'Survey was successfully destroyed.' }
format.json { head :no_content }
end
end
private
def set_survey
#survey = Survey.find(params[:id])
end
def survey_params
params.require(:survey).permit(:name, questions_attributes: [:id, :question_content], answers_attributes: [:id, :answer_content, :answer_type])
end
end
Survey form partial
<%= form_for(#survey) do |form| %>
<% if survey.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(survey.errors.count, "error") %> prohibited this survey from being saved:</h2>
<ul>
<% survey.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= form.label :name %>
<%= form.text_field :name, id: :survey_name %>
</div>
<%= form.fields_for :questions do |builder| %>
<fieldset>
<%= builder.label :question_content, "Question" %><br/>
<%= builder.text_area :question_content %><br/>
<%= form.fields_for :answers do |f| %>
<fieldset>
<%= f.text_area :answer_type %>
<%= f.text_area :answer_content %><br/>
</fieldset>
</fieldset>
<% end %>
<%end %>
<div class="actions">
<%= form.submit %>
</div>
I want to implement question and answer in single page i.e survey. Any help will appreciated.
Problem : Unable to save answers_attributes to database but Question attributes work perfectly fine. I am probably making mistake somewhere in controller not sure.

Answer 1

You need to change the way you're building the answer fields, so that they're referenced as fields_for questions, not surveys. Try changing this piece of code:
<%= form.fields_for :questions do |builder| %>
<fieldset>
<%= builder.label :question_content, "Question" %><br/>
<%= builder.text_area :question_content %><br/>
<%= form.fields_for :answers do |f| %>
<fieldset>
<%= f.text_area :answer_type %>
<%= f.text_area :answer_content %><br/>
</fieldset>
</fieldset>
<% end %>
<%end %>
to this:
<%= form.fields_for :questions do |builder| %>
<fieldset>
<%= builder.label :question_content, "Question" %><br/>
<%= builder.text_area :question_content %><br/>
<%= builder.fields_for :answers do |f| %>
<fieldset>
<%= f.text_area :answer_type %>
<%= f.text_area :answer_content %><br/>
</fieldset>
<% end %>
</fieldset>
<% end %>
(Note: the meaningful change is changing form.fields_for to builder.fields_for)