Rails Controllers with DataMapper

books_controller.rb

# This class is responsible for the Books REST interface.
#
class BooksController < ApplicationController

  # Get a book by the id
  before_filter :get_book, only: [:edit, :update, :show, :destroy]

  #  Renders the form to create a new Book.
  #
  def new
    @book = Book.new
  end

  # Creates a new Book from the params and redirects to edit view.
  #
  def create
    @book = Book.create(params[:book])
    redirect_to book_path(@book)
  end

  # Renders the form for a given book. 
  #
  def edit
  end

  # Updates a Book from the params and redirects to edit view.
  #
  def update
    @book.update(params[:book])
    redirect_to edit_book_path(@book)
  end

  # Renders all books
  #
  def index
    @books = Book.all
  end

  # Renders a Book
  #
  def show
  end

  # Destroys the Book object from database
  #
  def destroy
    @book.destroy
    redirect_to action: :index
  end

  private

  def get_book
    @book = Book.get(params[:id])
  end
end