Rails 4 Standard CRUD Controller

books_controller.rb

# No flash messages are set with this controller.
#
# This is a fairly basic / bare controller which does only the basic CRUD.
class BooksController < ApplicationController
  respond_to :html, :xml, :json

  before_action :set_book, only: [:show, :edit, :update, :destroy]

  def index
    respond_with @books = Book.all
  end

  def show
    respond_with @book
  end

  def new
    respond_with @book = Book.new
  end

  def edit
    respond_with @book
  end

  def create
    respond_with @book = Book.create(book_params)
  end

  def update
    @book.update(book_params)

    respond_with @book
  end

  def destroy
    # Destroy returns the object (i.e. self); though I believe Mongoid returns a boolean - need to double check this
    @book.destroy
    
    respond_with @book.destroy
  end

  private

  def set_book
    @book = Book.find(params[:id])
  end

  def book_params
    params[:book].permit(:title, :isbn, :price)
  end
end

books_customized_controller.rb

class BooksController < ApplicationController
  respond_to :html, :xml, :json

  before_action :set_book, only: [:show, :edit, :update, :destroy]

  def index
    respond_with @books = Book.all
  end

  def show
    respond_with @book
  end

  def new
    respond_with @book = Book.new
  end

  def edit
    respond_with @book
  end

  def create
    # In order to set the flash, we need to know if the create was successful.
    # Since `create` always returns an object we won't know if it's successful,
    # without re-validating or checking the errors.
    #
    # The cleaner way is to just initialize a new object, then check the call
    # to save; which will be truthy on a valid model and successful save.
    @book = Book.new(book_params)

    if @book.save
      flash[:notice] = "Book was successfully created."
    end

    respond_with @book
  end

  def update
    # Update returns truthy if the model was valid and the save successful.
    # So it's fine to just make the call.
    if @book.update(book_params)
      flash[:notice] = "Book was successfully updated."
    end

    # respond_with is very smart / magical. It knows that only on a
    # successful update should the location option be used as a
    # redirect.
    respond_with @book, location: root_url
  end

  def destroy
    @book.destroy
    
    flash[:notice] = "Book was successfully destroyed."
    
    respond_with @book
  end

  private

  def set_book
    @book = Book.find(params[:id])
  end

  def book_params
    params[:book].permit(:title, :isbn, :price)
  end
end