royketelaar royketelaar - 9 days ago 5
Ruby Question

Undefined method error on a nested resource index page

As a follow up to this earlier question, which has been solved

I have made a beginning with a rails app where I can create Collections. Each Collections is able to have multiple Photos. I can now create these Collections and Photos. But whenever I try to visit /collections/1/photos it has a problem with this line in my photos index

undefined method `photo_path' for #<#<Class:0x007fb8c40f1b38>:0x007fb8c88673a0>

<td><%= link_to 'Show', photo %></td>


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
redirect_to @photo
format.html { redirect_to @photo, notice: 'Photo was successfully created.' }
format.json { render :show, status: :created, location: @photo }
else
format.html { render :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 { render :show, status: :ok, location: @photo }
else
format.html { render :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, notice: 'Photo was successfully destroyed.' }
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(:name, :collection_id)
end
end


routes.rb

Rails.application.routes.draw do
resources :collections do
resources :photos
end
end


/photos/index.html

<p id="notice"><%= notice %></p>

<h1>Photos</h1>

<table>
<thead>
<tr>
<th colspan="3"></th>
</tr>
</thead>

<tbody>
<% @photos.each do |photo| %>
<tr>
<td><%= photo.name %></td>
<td><%= link_to 'Show', photo %></td>
<td><%= link_to 'Edit', edit_photo_path(photo) %></td>
<td><%= link_to 'Destroy', photo, method: :delete, data: { confirm: 'Are you sure?' } %></td>
</tr>
<% end %>
</tbody>
</table>

<br>

<%= link_to 'New Photo', new_collection_photo_path %>


collection.rb

class Collection < ApplicationRecord
has_many :photos
end


photo.rb

class Photo < ApplicationRecord
belongs_to :collection
end


I use Rails 5.0.0.1 and ruby 2.3.0

Answer

Use this your show and delete link path is wrong

<td><%= link_to 'Show', collection_photo_path(@collection, photo) %></td>
<td><%= link_to 'Edit', edit_collection_photo_path(@collection, photo) %></td>
<td><%= link_to 'Destroy', 
collection_photo_path(@collection, photo), method: :delete, data: { confirm: 'Are you sure?' } %></td>

Links should be made this , from controller you should intialize @collection

def index
  @collction = Collection.find(params[:collection_id])
  @photos = @collction.photos
end
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