Rails 4 - Nested Routes and Form Parameters - ruby-on-rails

Question

When I'm trying to create a new "participation" in my Rails4 application and it seems like there is something wrong with my parameters. Actually this is not causing any problems in application (or I didn't notice it) but still I would like to fix it. You can see 2 "examination_id" parameters one of them is null and the other one is equal to 1.
REQUEST PARAMETERS:
{"utf8"=>"✓",
"authenticity_token"=>"XZ71eV0zxrnTBilzvEtLlHLwoAb+qKdDfxOHjrAHUPg=",
"participation"=>
{
"language_preference"=>"Türkçe",
"exam_center_preference"=>"1",
"disability"=>"1",
"user_id"=>"1",
"examination_id"=>""
},
"commit"=>"Sınava Başvur",
"examination_id"=>"1"
}
routes.rb:
resources :examinations do
resources :participations do
member do
get :update_profile_information
end
end
end
participation.rb:
class Participation < ActiveRecord::Base
belongs_to :user
belongs_to :examination
before_save :verification_key_generator
end
participations_controller.rb:
class ParticipationsController < ApplicationController
before_filter :authenticate_user!
before_action :set_participation, only: [:show, :edit, :update, :destroy]
before_filter :get_examination
def get_examination
#examination = Examination.find(params[:examination_id])
end
def index
#participations = #examination.participations
end
def show
#participation = #examination.participations.find(params[:id])
end
def new
#participation = Participation.new
end
def create
#participation = #examination.participations.new(participation_params)
#participation.user = current_user
respond_to do |format|
if #participation.save
format.html { redirect_to [#examination, #participation], notice: 'Başvuru işlemi başarıyla tamamlandı!' }
format.json { render action: 'show', status: :created, location: [#examination, #participation] }
else
render 'new'
format.html { render action: 'new' }
format.json { render json: #participation.errors, status: :unprocessable_entity }
end
end
end
def update
respond_to do |format|
if #participation.update(participation_params)
format.html { redirect_to [#examination, #participation], notice: 'Başvurunuz Başarıyla Güncellendi!' }
format.json { head :no_content }
else
format.html { render action: 'edit' }
format.json { render json: participation.errors, status: :unprocessable_entity }
end
end
end
private
def set_participation
#participation = Participation.find(params[:id])
end
def participation_params
params.require(:participation).permit(:user_id, :examination_id, :payment_status, :language_preference, :exam_center_preference, :disability)
end
end
app/views/participations/_form.html.erb:
<%= simple_form_for([#examination, #participation], html:{class: "well"}) do |f| %>
<%= f.input :user_id, :as => :hidden, :input_html => { :value => current_user.id } %>
<%= f.input :examination_id, as: :hidden %>
<%= f.input :language_preference, collection: ["Türkçe", "İngilizce", "Rusça"], label: 'Sınav Dili Tercihi' %>
<%= f.input :exam_center_preference, collection:ExamCenter.all, label: 'Sınav Merkezi Seçiniz', label_method: :city %>
<%= f.input :disability, inline_label: 'Yardımcı İstiyorum', label: false %>
<%= f.button :submit, "Sınava Başvur" %>
<% end %>
app/views/participations/new.html.erb:
<%= simple_form_for([#examination, #participation]) do |f| %>
<%= f.error_notification %>
<%= f.input :language_preference, collection: ["Türkçe", "İngilizce", "Rusça"], label: 'Sınav Dili Tercihi' %>
<%= f.input :exam_center_preference, collection:ExamCenter.all, label: 'Sınav Merkezi Seçiniz', label_method: :city %>
<%= f.input :disability, inline_label: 'Yardımcı İstiyorum', label: false %>
<%= f.input :user_id, :as => :hidden, :input_html => { :value => current_user.id } %>
<%= f.input :examination_id, as: :hidden %>
<%= f.button :submit, "Sınava Başvur" %>
<% end %>
sa

Answer 1

When you're using
<%= simple_form_for([#examination, #participation], html:{class: "well"}) do |f| %>
to generate the form, it will set the action to be /examinations/[examination_id]/participations so the routes/action will know the examination_id from the url itself.
So, you don't need to pass examination_id separately as hidden field that you're setting as
<%= f.input :examination_id, as: :hidden %>
Once you remove this hidden field the request parameters will look like:
{"utf8"=>"✓",
"authenticity_token"=>"XZ71eV0zxrnTBilzvEtLlHLwoAb+qKdDfxOHjrAHUPg=",
"participation"=>
{
"language_preference"=>"Türkçe",
"exam_center_preference"=>"1",
"disability"=>"1",
"user_id"=>"1"
},
"commit"=>"Sınava Başvur",
"examination_id"=>"1"
}