N + 1 query fix

Gemfile

@@ -93,6 +93,8 @@ group :development do
   gem 'spring-watcher-listen', '~> 2.0.0'
   # When mail is sent from your application, Letter Opener will open a preview in the browser instead of sending.
   gem 'letter_opener', '~> 1.4', '>= 1.4.1'
+  # help to kill N+1 queries and unused eager loading.
+  gem 'bullet', '~> 5.5', '>= 5.5.1'
 end
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem

Gemfile.lock

@@ -54,6 +54,9 @@ GEM
       autoprefixer-rails (>= 5.2.1)
       sass (>= 3.3.4)
     builder (3.2.3)
+    bullet (5.5.1)
+      activesupport (>= 3.0.0)
+      uniform_notifier (~> 1.10.0)
     byebug (9.0.6)
     capybara (2.14.0)
       addressable
@@ -287,6 +290,7 @@ GEM
     uglifier (3.2.0)
       execjs (>= 0.3.0, < 3)
     unicode-display_width (1.2.1)
+    uniform_notifier (1.10.0)
     warden (1.2.7)
       rack (>= 1.0)
     web-console (3.5.1)
@@ -307,6 +311,7 @@ PLATFORMS
 DEPENDENCIES
   active_link_to (~> 1.0, >= 1.0.4)
   bootstrap-sass (~> 3.3.6)
+  bullet (~> 5.5, >= 5.5.1)
   byebug
   capybara (~> 2.13)
   carrierwave (~> 1.0)

app/controllers/admin_controller.rb

@@ -8,7 +8,7 @@ class AdminController < ApplicationController
 
   # GET /admin/orders
   def orders
-    @orders = Order.page(params[:page]).per(5)
+    @orders = Order.includes(:product_items).page(params[:page]).per(5)
   end
 
   private

app/controllers/categories_controller.rb

 class CategoriesController < ApplicationController
   def show
     @category = Category.find(params[:id])
-    @products = @category.products.page(params[:page]).per(5)
+    @products = @category.products.includes(:user).page(params[:page]).per(5)
   end
 end
\ No newline at end of file

app/controllers/static_pages_controller.rb

 class StaticPagesController < ApplicationController
   def index
-    @latest_products = Product.page(params[:page]).per(5)
+    @latest_products = Product.includes(:user).page(params[:page]).per(5)
     # @TODO: Get recommended products
     @recommended_products = Product.last(6)
     # session.clear

app/controllers/users_controller.rb

@@ -13,6 +13,6 @@ class UsersController < ApplicationController
 
   # GET /users/orders
   def orders
-    @orders = current_user.orders.page(params[:page]).per(5)
+    @orders = current_user.orders.includes(:product_items).page(params[:page]).per(5)
   end
 end
\ No newline at end of file

app/models/product.rb

@@ -10,7 +10,7 @@ class Product < ApplicationRecord
   validates :user_id, presence: true
 
   def in_stock?(required_quantity)
-    return false if required_quantity <= 0
+    return false if required_quantity.to_i < 0
     quantity >= required_quantity.to_i
   end
 

app/services/search.rb

@@ -19,6 +19,6 @@ class Search
 
   def matched_products(products)
     product_ids = products.map { |product| product[:id.to_s] }
-    Product.find(product_ids)
+    Product.includes(:user).find(product_ids)
   end
 end
\ No newline at end of file

config/environments/development.rb

@@ -53,4 +53,13 @@ Rails.application.configure do
   config.file_watcher = ActiveSupport::EventedFileUpdateChecker
 
   config.action_mailer.delivery_method = :letter_opener
+
+  config.after_initialize do
+    Bullet.enable = true
+    Bullet.alert = true
+    Bullet.bullet_logger = true
+    Bullet.console = true
+    Bullet.rails_logger = true
+    Bullet.add_footer = true
+  end
 end