RAILS : uninitialized constant PhotosController::Photo [Ruby on rails]

Question

He, I have a problem with my code and I'm looking for a solution for 2 hours now. I'm new on ruby on rails ( and rails .. ) and I have this error : NameError in PhotosController#new uninitialized constant PhotosController::Photo

here my code so you can help me on it !

photos_controller.rb :

 class PhotosController < ApplicationController
  before_action :set_photo, only: [:show, :edit, :update, :destroy]

  # GET /photos
  # GET /photos.json
  def index
    @photos = Photo.all 
  end

  # GET /photos/1
  # GET /photos/1.json
  def show
  end

  # GET /photos/new
  def new
    @photo = Photo.new
  end

  # GET /photos/1/edit
  def edit
  end

  # POST /photos
  # POST /photos.json
  def create
    @photo = Photo.new(photo_params)

    respond_to do |format|
      if @photo.save
        format.html { redirect_to @photo, notice: 'Photo was successfully created.' }
        format.json { render action: 'show', status: :created, location: @photo }
      else
        format.html { render action: 'new' }
        format.json { render json: @photo.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /photos/1
  # PATCH/PUT /photos/1.json
  def update
    respond_to do |format|
      if @photo.update(photo_params)
        format.html { redirect_to @photo, notice: 'Photo was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @photo.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /photos/1
  # DELETE /photos/1.json
  def destroy
    @photo.destroy
    respond_to do |format|
      format.html { redirect_to photos_url }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_photo
      @photo = Photo.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def photo_params
      params.require(:photo).permit(:image)
    end
end

photo.rb :

class Photo < ActiveRecord::Base
has_attached_file :image
end

The page I temp to reach ( //.../photos/new ) : new.html.erb :

<h1>New photo</h1>

and my route file :

PYL::Application.routes.draw do
  get "photos/test"
  get "photos/update"
  get "photos/show"
  get "photos/new"
  resources :photos
  get "photos/new"
  # The priority is based upon order of creation: first created -> highest priority.
  # See how all your routes lay out with "rake routes".

  # You can have the root of your site routed with "root"
   root 'photo#index'

  # Example of regular route:
  #   get 'products/:id' => 'catalog#view'

  # Example of named route that can be invoked with purchase_url(id: product.id)
  #   get 'products/:id/purchase' => 'catalog#purchase', as: :purchase

  # Example resource route (maps HTTP verbs to controller actions automatically):
  #   resources :products

  # Example resource route with options:
  #   resources :products do
  #     member do
  #       get 'short'
  #       post 'toggle'
  #     end
  #
  #     collection do
  #       get 'sold'
  #     end
  #   end

  # Example resource route with sub-resources:
  #   resources :products do
  #     resources :comments, :sales
  #     resource :seller
  #   end

  # Example resource route with more complex sub-resources:
  #   resources :products do
  #     resources :comments
  #     resources :sales do
  #       get 'recent', on: :collection
  #     end
  #   end

  # Example resource route with concerns:
  #   concern :toggleable do
  #     post 'toggle'
  #   end
  #   resources :posts, concerns: :toggleable
  #   resources :photos, concerns: :toggleable

  # Example resource route within a namespace:
  #   namespace :admin do
  #     # Directs /admin/products/* to Admin::ProductsController
  #     # (app/controllers/admin/products_controller.rb)
  #     resources :products
  #   end
end

If you have an idea, please help me :)

Answer 1

You named your model class Photos instead of Photo. It should be:

class Photo < ActiveRecord::Base
  has_attached_file :image
end