undefined method '_path' with references - ruby-on-rails-4

Question

I'm looking for make draw lesson with a differente gallery link with each lessons for the users can uplaod there work in.
I have a controller, model and view named "lesson" and the linked gallery is "illst_repot"
I have linked the illust_repot with references.
lesson:references and user:references
I have no problem on the index page, but I have a problem on new page
undefined method `illust_reports_path'
localhost:3000/lessons/1/illust_reports/new
This is my routes
lesson_illust_reports GET /lessons/:lesson_id/illust_reports(.:format) illust_reports#index
POST /lessons/:lesson_id/illust_reports(.:format) illust_reports#create
new_lesson_illust_report GET /lessons/:lesson_id/illust_reports/new(.:format) illust_reports#new
edit_lesson_illust_report GET /lessons/:lesson_id/illust_reports/:id/edit(.:format) illust_reports#edit
lesson_illust_report GET /lessons/:lesson_id/illust_reports/:id(.:format) illust_reports#show
PATCH /lessons/:lesson_id/illust_reports/:id(.:format) illust_reports#update
PUT /lessons/:lesson_id/illust_reports/:id(.:format) illust_reports#update
DELETE /lessons/:lesson_id/illust_reports/:id(.:format) illust_reports#destroy
lessons GET /lessons(.:format) lessons#index
POST /lessons(.:format) lessons#create
new_lesson GET /lessons/new(.:format) lessons#new
edit_lesson GET /lessons/:id/edit(.:format) lessons#edit
lesson GET /lessons/:id(.:format) lessons#show
PATCH /lessons/:id(.:format) lessons#update
PUT /lessons/:id(.:format) lessons#update
DELETE /lessons/:id(.:format) lessons#destroy
routes.rb
resources :lessons do
resources :illust_reports
end
illust_reports_controller.rb
class IllustReportsController < ApplicationController
before_action :set_illust_report, only: [:show, :edit, :update, :destroy]
before_action :authenticate_user!, except: [:index, :show]
before_action :illust_report_owner, only: [:edit, :update, :destroy]
# GET /illust_reports
# GET /illust_reports.json
def index
#illust_reports = IllustReport.all
end
def illust_report_owner
unless #illust_report.user_id == current_user.id
flash[:notice] = "Accès refusé car tu n'es pas l'auteur de ce billet."
redirect_to illust_reports_path
end
end
# GET /illust_reports/1
# GET /illust_reports/1.json
def show
end
# GET /illust_reports/new
def new
#illust_report = current_user.illust_reports.build
end
# GET /illust_reports/1/edit
def edit
end
# POST /illust_reports
# POST /illust_reports.json
def create
#illust_report = current_user.illust_reports.build(illust_report_params)
respond_to do |format|
if #illust_report.save
format.html { redirect_to #illust_report, notice: 'Illust report was successfully created.' }
format.json { render :show, status: :created, location: #illust_report }
else
format.html { render :new }
format.json { render json: #illust_report.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /illust_reports/1
# PATCH/PUT /illust_reports/1.json
def update
respond_to do |format|
if #illust_report.update(illust_report_params)
format.html { redirect_to #illust_report, notice: 'Illust report was successfully updated.' }
format.json { render :show, status: :ok, location: #illust_report }
else
format.html { render :edit }
format.json { render json: #illust_report.errors, status: :unprocessable_entity }
end
end
end
# DELETE /illust_reports/1
# DELETE /illust_reports/1.json
def destroy
#illust_report.destroy
respond_to do |format|
format.html { redirect_to illust_reports_url, notice: 'Illust report was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_illust_report
#illust_report = IllustReport.find_by(id: params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def illust_report_params
params.require(:illust_report).permit(:title, :image, :commentaire, :lesson_id, :user_id)
end
end
_form.html.erb
<%= form_for(#illust_report) do |f| %>
<% if #illust_report.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#illust_report.errors.count, "error") %> prohibited this illust_report from being saved:</h2>
<ul>
<% #illust_report.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
The model are linked.
I'm beginner with rails, I have searched a long time on google, and stack, and make many test before write this message.
Where is the problem ?
Thank you very much for your time.

Answer 1

undefined method `illust_reports_path'
You have nested resources. So the form_for should look like below
<%= form_for [#lesson, #illust_report] do |f| %>
and change the illust_reports_controller's new method like below
def new
#lesson = Lesson.find(params[:lesson_id])
#illust_report = current_user.illust_reports.build
end

Answer 2

Does lesson_illust_reports_path work?
As your illust_report resource is namespaced inside your lessons resource, you have to prepend lesson.