single method for updating cart item state / fixed problems with sinatra contrib

front-api/app.rb

@@ -2,7 +2,7 @@ require 'sinatra'
 require 'sinatra/activerecord'
 require './config'
 require 'json'
-require 'sinatra/contrib'
+require 'sinatra/cookies'
 
 Dir[File.dirname(__FILE__) + '/models/*.rb'].each {|file| require file }
 
@@ -15,16 +15,14 @@ before do
   #       domain is allowed
   headers 'Access-Control-Allow-Origin' => '*', 
           'Access-Control-Allow-Methods' => ['OPTIONS', 'GET', 'POST']  
+  
+  request.body.rewind
+  json_string = request.body.read 
+  @json_params = JSON.parse json_string if json_string.length > 1
 end
 
-helpers do
-  def json_params
-    request.body.read
-    JSON.parse request.body.read
-  end
-end
 
-register Sinatra::Contrib
+
 helpers Sinatra::Cookies
 
 

front-api/controllers/cart.rb

@@ -21,10 +21,9 @@ get '/cart/item' do
   Cart.find_or_create(anonymous_id, -1).item_in_carts.to_json
 end
 
-post '/cart/item/add' do
-  #cart_id = Cart.find_or_create(anonymous_id, -1).id
-  #item_id = params[:id].to_i
-  #ItemInCart.add(cart_id, item_id)
-  #json_params.to_json
-  "not ready yet".to_json
+post '/cart/item' do
+  cart_id = Cart.find_or_create(anonymous_id, -1).id
+  item_id = @json_params["item_id"]
+  count = @json_params["count"]
+  ItemInCart.update_state(cart_id, item_id, count).to_json
 end

front-api/models/cart.rb

@@ -1,6 +1,5 @@
 class Cart < ActiveRecord::Base
-  has_many :item_in_carts
-
+  has_many :item_in_carts, -> { order "created_at" }
   def self.find_or_create(anonymous_id, user_id)
     cart = Cart.where(user_id: user_id).where(ordered: false).first
     cart ||= Cart.where(anonymous_id_string: anonymous_id).where(ordered: false).first

front-api/models/item_in_cart.rb

@@ -1,4 +1,20 @@
 class ItemInCart < ActiveRecord::Base
-  belongs_to :cart 
-  belongs_to :item 
-end
+  belongs_to :cart
+  belongs_to :item
+
+  validates_uniqueness_of :item_id, scope: :cart_id
+  validates :item_id, presence: true
+  validates :cart_id, presence: true
+
+  def self.update_state(cart_id, item_id, count)
+    item_in_cart = nil
+    ItemInCart.transaction do
+      item_in_cart = ItemInCart.where(cart_id: cart_id, item_id: item_id).first
+      item_in_cart ||= ItemInCart.new(cart_id: cart_id, item_id: item_id)
+      item_in_cart.count = count
+      item_in_cart.save!
+      item_in_cart.destroy! if count <= 0
+    end
+    return item_in_cart
+  end
+end