Better syntax

app/controllers/cart_payments_controller.rb

@@ -12,7 +12,7 @@ class CartPaymentsController < ApplicationController
     param :path, :cart_id, :integer, :required, 'Cart ID'
     param :body, :cart, :versionCart, :required, 'Cart'
     response :ok, 'Success', :readTransaction
-    response :not_found, 'No cart with that ID'
+    response :not_found, 'No cart with that ID or it is expired'
     response :conflict, 'The user\'s balance is too low'
     response :precondition_required, 'The cart is stale'
     response :gone, 'The cart payment is already being processed'

app/controllers/carts_controller.rb

@@ -48,6 +48,9 @@ class CartsController < ApplicationController
     property :id, :integer, :optional, 'Cart ID'
     property :user_id, :integer, :optional, 'User ID'
     property :total_price, :integer, :optional, 'Total Cart price'
+    property :expires_at, :date_time, :optional,
+             'Date and time at which the cart expires, making it read-only, '\
+             'not payable for, and releasing product reservations'
     property :lock_version, :integer, :optional, 'Cart version'
     property :cart_items, :array, :optional, 'Cart Items',
       'items' => {'$ref' => 'readCartItem'}
@@ -76,7 +79,7 @@ class CartsController < ApplicationController
   before_action -> { doorkeeper_authorize! :checkout }
 
   def show
-    cart = Cart.find_by_id(params[:id])
+    cart = Cart.find_by(id: params[:id])
 
     if cart.present?
       render json: cart
@@ -103,6 +106,7 @@ def update
     if cart.save
       render json: cart, status: :ok, location: cart
     else
+      cart.reload
       render json: cart, status: :conflict, location: cart
     end
   end

app/controllers/products_controller.rb

@@ -98,7 +98,7 @@ class ProductsController < ApplicationController
   before_action -> { doorkeeper_authorize! :admin }, only: [:create, :update]
 
   def show
-    product = Product.find_by_id(params[:id])
+    product = Product.find_by(id: params[:id])
 
     if product.present?
       render json: product

app/controllers/transactions_controller.rb

@@ -69,7 +69,7 @@ class TransactionsController < ApplicationController
   before_action :doorkeeper_authorize!
 
   def show
-    transaction = Transaction.find_by_id(params[:id])
+    transaction = Transaction.find_by(id: params[:id])
 
     if transaction.present?
       renter json: transaction

app/controllers/users_controller.rb

@@ -78,7 +78,7 @@ class UsersController < ApplicationController
   before_action -> { doorkeeper_authorize! :admin }, only: [:create, :update]
 
   def show
-    user = User.find_by_id(params[:id])
+    user = User.find_by(id: params[:id])
 
     if user.present?
       render json: user

app/interactors/abort_if_expired_cart.rb

@@ -0,0 +1,7 @@
+class AbortIfExpiredCart
+  include Interactor
+
+  def call
+    context.fail!(message: 'generic.not_found') if context.cart.expired?
+  end
+end

app/interactors/pay_cart.rb

@@ -2,6 +2,7 @@ class PayCart
   include Interactor::Organizer
 
   organize ResolveCartAndUser,
+           AbortIfExpiredCart,
            MarkCartAsProcessing,
            InitializeTransaction,
            LogRequestingClientInTransaction,

app/interactors/resolve_cart_and_user.rb

@@ -3,7 +3,7 @@ class ResolveCartAndUser
 
   def call
     begin
-      context.cart = Cart.find_by_id!(context.cart_id)
+      context.cart = Cart.find_by!(id: context.cart_id)
     rescue ActiveRecord::RecordNotFound
       context.fail!(message: 'generic.not_found')
     end

app/interactors/resolve_user.rb

@@ -2,7 +2,7 @@ class ResolveUser
   include Interactor
 
   def call
-    context.user = User.find_by_id!(context.user_id)
+    context.user = User.find_by!(id: context.user_id)
   rescue ActiveRecord::RecordNotFound
     context.fail!(message: 'generic.not_found')
   end

app/models/cart.rb

@@ -1,8 +1,34 @@
 class Cart < ActiveRecord::Base
+  EXPIRE_AFTER = 300 # seconds
+
   belongs_to :user
   has_many :cart_items, dependent: :destroy, autosave: true
 
+  validate :ensure_unexpired
+
+  scope :unexpired, -> { where unexpired_condition }
+
+  def self.unexpired_condition
+    arel_table[:updated_at].gteq(EXPIRE_AFTER.seconds.ago)
+  end
+
   def total_price
     cart_items.map(&:total_price).reduce(:+)
   end
+
+  def expires_at
+    (updated_at || DateTime.current) + EXPIRE_AFTER.seconds
+  end
+
+  def expired?
+    DateTime.current > expires_at
+  end
+
+  private
+
+  def ensure_unexpired
+    if expired?
+      errors.add :expires_at, "can't be in the past"
+    end
+  end
 end

app/models/cart_item.rb

@@ -5,6 +5,8 @@ class CartItem < ActiveRecord::Base
 
   validate :enough_items_present_in_pricing
 
+  scope :unexpired, -> { joins(:cart).where(Cart.unexpired_condition) }
+
   def product_name
     product.try(:name) || ''
   end

app/models/pricing.rb

@@ -6,6 +6,6 @@ class Pricing < ActiveRecord::Base
   validates :price, numericality: { only_integer: true }
 
   def available_quantity
-    quantity - cart_items.sum(:quantity)
+    quantity - cart_items.unexpired.sum(:quantity)
   end
 end

app/representers/cart_representer.rb

@@ -4,6 +4,7 @@ class CartRepresenter < ApplicationDecorator
   property :lock_version, type: Integer
   property :user_id, type: Integer
   property :total_price, writeable: false, type: Integer
+  property :expires_at, writeable: false, type: Date
 
   collection(
     :cart_items,

spec/controllers/carts_controller_spec.rb

@@ -11,7 +11,7 @@
   }
 
   describe '#show' do
-    before {Cart.find_by_id(1) || create(:cart, id: 1)}
+    before { Cart.find_by(id: 1) || create(:cart, id: 1) }
     before { get :show, params: { id: cart_id } }
 
     context 'when the resource exists' do
@@ -49,14 +49,14 @@
 
   describe '#update via JSON' do
     before do
-      cart = Cart.find_by_id(1) || create(:cart, id: 1)
+      cart = Cart.find_by(id: 1) || create(:cart, id: 1)
       cart.update_attribute(:user_id, 2)
     end
     before {request.env['CONTENT_TYPE'] = 'application/json'}
 
     describe 'with valid parameters' do
       it 'updates the Cart 1' do
-        cart = Cart.find_by_id(1)
+        cart = Cart.find_by(id: 1)
         expect {
           put :update, body: JSON.generate(valid_attributes), params: { id: '1' }
           cart.reload

spec/controllers/products_controller_spec.rb

@@ -11,7 +11,7 @@
   }
 
   describe '#show' do
-    before {Product.find_by_id(1) || create(:product, id: 1)}
+    before { Product.find_by(id: 1) || create(:product, id: 1) }
     before { get :show, params: { id: product_id } }
 
     context 'when the resource exists' do
@@ -32,7 +32,9 @@
     before {get :index}
 
     context 'when there are products' do
-      before {(1..3).each {|y| Product.find_by_id(y) || create(:product, id: y)}}
+      before do
+        (1..3).each { |y| Product.find_by(id: y) || create(:product, id: y) }
+      end
 
       its(:content_type) {is_expected.to eq 'application/json'}
       it {is_expected.to have_http_status(:ok)}
@@ -65,14 +67,14 @@
 
   describe '#update via JSON' do
     before do
-      product = Product.find_by_id(1) || create(:product, id: 1)
+      product = Product.find_by(id: 1) || create(:product, id: 1)
       product.update_attribute(:name, 'Turbriskafil')
     end
     before { request.env['CONTENT_TYPE'] = 'application/json' }
 
     describe 'with valid parameters' do
       it 'updates the Product 1' do
-        product = Product.find_by_id(1)
+        product = Product.find_by(id: 1)
         expect {
           put :update, body: JSON.generate(valid_attributes), params: { id: '1' }
           product.reload

spec/controllers/users_controller_spec.rb

@@ -11,7 +11,7 @@
   }
 
   describe '#show' do
-    before {User.find_by_id(1) || create(:user, id: 1)}
+    before { User.find_by(id: 1) || create(:user, id: 1) }
     before { get :show, params: { id: user_id } }
 
     context 'when the resource exists' do
@@ -49,14 +49,14 @@
 
   describe '#update via JSON' do
     before do
-      user = User.find_by_id(1) || create(:user, id: 1)
+      user = User.find_by(id: 1) || create(:user, id: 1)
       user.update_attribute(:name, 'Sheldon')
     end
     before { request.env['CONTENT_TYPE'] = 'application/json' }
 
     describe 'with valid parameters' do
       it 'updates the User 1' do
-        user = User.find_by_id(1)
+        user = User.find_by(id: 1)
         expect {
           put :update, body: JSON.generate(valid_attributes), params: { id: '1' }
           user.reload

spec/interactors/pay_cart_spec.rb

@@ -31,7 +31,7 @@
     end
 
     before do
-      allow(Cart).to receive(:find_by_id!).with(cart.id).and_return(cart)
+      allow(Cart).to receive(:find_by!).with(id: cart.id).and_return(cart)
     end
 
     context 'when everything is swell' do
@@ -108,7 +108,7 @@
 
     context 'when there\'s no cart with that ID' do
       before do
-        allow(Cart).to receive(:find_by_id!).with(cart.id).
+        allow(Cart).to receive(:find_by!).with(id: cart.id).
           and_raise(ActiveRecord::RecordNotFound)
       end
 
@@ -164,7 +164,7 @@
       it 'shouldn\'t do things twice' do
         # Don't return the object in the cart variable, as this would share
         # the same instance of the object between all threads
-        allow(Cart).to receive(:find_by_id!).with(cart.id).and_call_original
+        allow(Cart).to receive(:find_by!).with(id: cart.id).and_call_original
         expect do
           threaded(3) do
             PayCart.new(

spec/interactors/resolve_cart_and_user_spec.rb

@@ -9,7 +9,7 @@
     let(:cart) { double user: user }
 
     before do
-      allow(Cart).to receive(:find_by_id!).with(1).and_return(cart)
+      allow(Cart).to receive(:find_by!).with(id: 1).and_return(cart)
     end
 
     context 'when the cart exists' do
@@ -30,7 +30,7 @@
 
     context 'when the cart doesn\'t exist' do
       before do
-        allow(Cart).to receive(:find_by_id!).with(1).
+        allow(Cart).to receive(:find_by!).with(id: 1).
           and_raise(ActiveRecord::RecordNotFound)
       end
       before { interactor.call rescue Interactor::Failure }

spec/interactors/resolve_user_spec.rb

@@ -8,7 +8,7 @@
 
   context 'when the user exists' do
     before do
-      allow(User).to receive(:find_by_id!).with(1).and_return(user)
+      allow(User).to receive(:find_by!).with(id: 1).and_return(user)
     end
 
     before { interactor.call }
@@ -24,7 +24,7 @@
 
   context 'when the user doesn\'t exist' do
     before do
-      allow(User).to receive(:find_by_id!).
+      allow(User).to receive(:find_by!).
         and_raise(ActiveRecord::RecordNotFound)
     end
 

spec/interactors/user_deposit_spec.rb

@@ -34,7 +34,7 @@
 
     context 'when there\'s no user with that ID' do
       before do
-        allow(User).to receive(:find_by_id!).
+        allow(User).to receive(:find_by!).
           and_raise(ActiveRecord::RecordNotFound)
       end
 

spec/models/pricing_spec.rb

@@ -11,7 +11,10 @@
     end
 
     context 'there are currently blocked items' do
-      before {create_list(:cart_item, 2, pricing: pricing, quantity: 2)}
+      before do
+        cart = create(:cart)
+        create_list(:cart_item, 2, cart: cart, pricing: pricing, quantity: 2)
+      end
       it {is_expected.to eq 6}
     end
   end

spec/models/product_spec.rb

@@ -28,8 +28,13 @@
 
       context 'the product is in some carts' do
         before do
-          create(:cart_item, pricing: product.pricings[0], quantity: 3)
-          create(:cart_item, pricing: product.pricings[1], quantity: 2)
+          cart = create(:cart)
+          create(
+            :cart_item, cart: cart, pricing: product.pricings[0], quantity: 3
+          )
+          create(
+            :cart_item, cart: cart, pricing: product.pricings[1], quantity: 2
+          )
         end
 
         it {is_expected.to eq 15}