Two different controller patterns

_rails_controller_comparison.md

Rails Controller Comparison

This Gist compares two different patterns to writing your controllers. My personal preference is orders_first_controller.rb, please feel free to comment with pros and cons of both patterns.

Notes

For this example we are using locals in both examples since instance variables encourage a leaky controller and views.

Machine comparisons were performed with flog and flay

Both scored a 0 on flay.

orders_first_controller.rb

class OrdersFirstController < ApplicationController
  def create
    render_new unless new_order.save

    redirect_to orders_path
  end

  def edit
    render_edit
  end

  def index
    render locals: { orders: orders }
  end

  def new
    render_new
  end

  def show
    render locals: { order: order }
  end

  def update
    render_edit unless order.update_attributes(order_params)

    redirect_to orders_path
  end

  def render_new
    render :new, locals: { locations: locations, order: new_order }
  end

  def render_edit
    render :edit, locals: { locations: locations, order: order }
  end

  private

  def new_order
    @order ||= Order.new(order_params)
  end

  def order
    @order ||= Order.find(params[:id])
  end

  def orders
    @orders ||= Order.all
  end

  def order_params
    return {} unless params[:order]

    params
      .require(:order)
      .permit(:destination_location_id,
              :requested_delivery_date,
              :time_slot)
  end

  def locations
    @locations ||= Location.all
  end
end

# flog output
#    41.4: flog total
#     3.0: flog/method average
#
#     6.8: OrdersFirstController#update     app/controllers/orders_first_controller.rb:24
#     5.9: OrdersFirstController#order_params app/controllers/orders_first_controller.rb:52
#     5.6: OrdersFirstController#create     app/controllers/orders_first_controller.rb:2
#     3.7: OrdersFirstController#order      app/controllers/orders_first_controller.rb:44
#     3.4: OrdersFirstController#render_edit app/controllers/orders_first_controller.rb:34

orders_second_controller.rb

class OrdersSecondController < ApplicationController
  def create
    order = Order.new(order_params)

    if order.save
      redirect_to orders_path
    else
      render :new, locals: { order: order, locations: locations }
    end
  end

  def edit
    order = Order.find(params[:id])

    render locals: { order: order, locations: locations }
  end

  def index
    render locals: { orders: Order.all }
  end

  def new
    order = Order.new

    render locals: { order: order, locations: locations }
  end

  def show
    order = Order.find(params[:id])

    render locals: { order: order }
  end

  def update
    order = Order.find(params[:id])

    if order.update_attributes(order_params)
      redirect_to orders_path
    else
      render :edit, locals: { order: order, locations: locations }
    end
  end

  private

  def order_params
    return {} unless params[:order]

    params
      .require(:order)
      .permit(:destination_location_id,
              :requested_delivery_date,
              :time_slot)
  end

  def locations
    @locations ||= Location.all
  end
end

# flog output
#    43.3: flog total
#     4.8: flog/method average
#
#    10.7: OrdersSecondController#update    app/controllers/orders_second_controller.rb:34
#     8.1: OrdersSecondController#create    app/controllers/orders_second_controller.rb:2
#     5.9: OrdersSecondController#edit      app/controllers/orders_second_controller.rb:12
#     5.9: OrdersSecondController#order_params app/controllers/orders_second_controller.rb:46

class OrdersController < ApplicationController
  def create
    order = new_order(order_params: order_params)

    render_new(order: order) and return unless order.save

    redirect_to orders_path
  end

  def edit
    render_edit
  end

  def index
    render locals: { orders: orders }
  end

  def new
    render_new
  end

  def show
    render locals: { order: order }
  end

  def update
    render_edit and return unless order.update_attributes(order_params)

    redirect_to orders_path
  end

  private

  def order_params
    params
      .require(:order)
      .permit(:destination_location_id,
              :requested_delivery_date,
              :time_slot)
  end

  def locations
    @_locations ||= Location.all
  end

  def new_order(order_params: {})
    @_order ||= Order.new(order_params)
  end

  def order
    @_order ||= Order.find(params[:id])
  end

  def orders
    @_orders ||= Order.all
  end

  def render_new(order: new_order)
    render :new, locals: { order: order, locations: locations }
  end

  def render_edit
    render :edit, locals: { order: order, locations: locations }
  end
end