ひとつのモデルを立場の違うユーザで閲覧する場合のベストプラクティスを探る

#books_controller.rb
# GET books#index
def index
  if current_user.is_admin?
    @books = Book.all
  elsif params[:publisher_id]
    @publisher = Publisher.find params[:publisher_id]
    @books = @publisher.books # <= Publisher has_many :books, through: :publisher_users な感じ。
  else
    @books = current_user.books
  end
end

- #index.html.haml
%table.table
  %thead
    %tr
      %th
        Title
      %th
        Author
      %th
        Delete
  %tbody
    - @books.each do |b|
      %tr
        %td
          = link_to b do
            = b.title
        %td
          = link_to b.user do
            = b.user.name
        %td
          - if current_user.is_author?(b) || current_user.is_admin?
            = link_to b, method: :delete, class: 'btn btn-danger' do
              %i.icon-trash
              Delete

# spec/routing/books_routing_spec.rb
require "spec_helper"

describe BooksController do
  describe "routing" do
    it "recognizes and generates #index" do
      get("/books").should route_to("books#index")
    end
  end
end

# spec/routing/publishers/books_routing_spec.rb
require "spec_helper"

describe Publishers::BooksController do
  describe "routing" do
    it "recognizes and generates #index" do
      get("/publishers/1/books").should route_to("publishers/books#index", publisher_id: '1')
    end
  end
end

# spec/routing/admin/books_routing_spec.rb
require "spec_helper"

describe Admin::BooksController do
  describe "routing" do
    it "recognizes and generates #index" do
      get("/admin/books").should route_to("admin/books#index")
    end
  end
end

# routes.rb
Publisher::Application.routes.draw do
  resources :books
  resources :publishers do
    resources :books, module: :publishers, only: [:index]
  end
  namespace :admin do
    resources :books, only: [:index]
  end
end

#controller_specs.rb
require 'spec_helper'

describe BooksController do
  before :all do
    @user = FactoryGirl.create :user
    @user.confirm!

    @other = FactoryGirl.create :user
    @other.confirm!
  end

  before :each do
    sign_in @user
  end

  context '自分のbooks' do
    describe 'GET index' do
      before :all do
        my_book1 = FactoryGirl.create :book, user_id: @user.id
        my_book2 = FactoryGirl.create :book, user_id: @user.id
        not_my_book1 = FactoryGirl.create :book, user_id: @other.id
        not_my_book2 = FactoryGirl.create :book, user_id: @other.id
      end

      it '@booksのauthorがすべて自分であること' do
        get :index
        assigns(:books).should eq([my_book1, my_book2])
      end
    end
  end
end

# TODO あとの2つ
# ...

# app/controllers/books_controller.rb
class BooksController < ApplicationController
  def index
    @books = current_user.books
  end
end

# app/controllers/publishers/books_controller.rb
class Publishers::BooksController < ApplicationController
  # 権限とか例外とかはちょっと省略
  def index
    @publisher = Publisher.find params[:publisher_id]
    @books = @publisher.books
  end
end

# app/controllers/admin/books_controller.rb
class Admin::BooksController < ApplicationController
  def index
    @books = Books.all
  end
end

mkdir -p app/views/books
touch app/views/books/index.html.haml
mkdir -p app/views/publishers/books
touch app/views/publishers/books/index.html.haml
mkdir -p app/views/admin/books
touch app/views/admin/books/index.html.haml

# routes.rb
Publisher::Application.routes.draw do
  resources :books
  resources :publishers do
    resources :books, module: :publishers, only: [:index]
  end
  namespace :admin do
    resources :books, only: [:index]
  end

  # Add This !
  resources :users do
    resources :books, module: :users, only: [:index]
  end
end