Extracting the create action from the ProductsController. Found in Fearless Refactoring Rails Controllers, pg 31

create_product_controller.rb

# Declare the new route in routes.rb
post 'products' => 'create_product#create'
resources :products

# Intermediate state depending on inheritance to pass tests
class CreateProductController < ProductsController
  def create
    @product = Product.new(product_params)

    respond_to do |format|
      if @product.save
        format.html { redirect_to @product, notice: 'Product was successfully created.' }
        format.json { render “products/show”, status: :created, location: @product }
      else
        format.html { render “products/new” }
        format.json { render json: @product.errors, status: :unprocessable_entity }
      end
    end
  end
end

# Extracted dependencies from ProductsController. No longer relying on inheritance
class CreateProductController < ApplicationController
  before_filter :filter_the_things

  def create
    @product = Product.new(product_params)

    respond_to do |format|
      if @product.save
        format.html { redirect_to @product, notice: 'Product was successfully created.' }
        format.json { render “products/show”, status: :created, location: @product }
      else
        format.html { render “products/new” }
        format.json { render json: @product.errors, status: :unprocessable_entity }
      end
    end
  end

  private
  def product_params
    params.require(:product).permit(:name, :description)
  end

  def filter_the_things
    # contrived example code here
  end
end

# Kill the original :create route in routes.rb
post 'products' => 'create_product#create'
resources :products, except: [:create]