added etags on prepare_for_display items and menuitems

front-api/Gemfile

@@ -21,3 +21,4 @@ gem "json"
 gem 'puma'
 gem "sinatra-contrib"
 gem 'rerun'
+gem 'xxhash', '~> 0.3.0'

front-api/Gemfile.lock

@@ -88,6 +88,7 @@ GEM
       hitimes
     tzinfo (1.2.2)
       thread_safe (~> 0.1)
+    xxhash (0.3.0)
 
 PLATFORMS
   java
@@ -106,6 +107,7 @@ DEPENDENCIES
   sinatra
   sinatra-activerecord
   sinatra-contrib
+  xxhash (~> 0.3.0)
 
 BUNDLED WITH
    1.10.3

front-api/app.rb

@@ -4,6 +4,7 @@ require './config'
 require 'json'
 require 'sinatra/cookies'
 require 'elasticsearch'
+require 'xxhash'
 
 
 Dir[File.dirname(__FILE__) + '/models/*.rb'].each {|file| require file }
@@ -31,11 +32,14 @@ before do
 end
 
 
-
-
-
 helpers Sinatra::Cookies
 
+def xxhash(text)
+  seed = 31337
+  XXhash.xxh32(text, seed)
+end
+
+
 
 
 Dir[File.dirname(__FILE__) + '/controllers/*.rb'].each {|file| require file }

front-api/controllers/item.rb

@@ -1,5 +1,5 @@
 def prepare_items_for_mass_display(items)
-  items.to_json(
+  items_json = items.to_json(
      :except => [:created_at, :current_input_price, :stock, :on_display],
      :include => [
       :unit ,
@@ -7,6 +7,8 @@ def prepare_items_for_mass_display(items)
       :sub_category,
       :brand
   ])
+  etag xxhash(items_json)
+  items_json
 end
 
 def offset_and_limit_invalid?(offset, limit)

front-api/controllers/menu_item.rb

@@ -1,6 +1,8 @@
 get '/menuitem' do
     # list all menu items
-    MenuItem.eager_load(menu_sub_items: :menu_sub_sub_items)
+    menu_items_json = MenuItem.eager_load(menu_sub_items: :menu_sub_sub_items)
     .order("menu_items.ordinal, menu_sub_items.ordinal, menu_sub_sub_items.ordinal")
     .to_json(:include => [:menu_sub_items => {:include => :menu_sub_sub_items}])
+    etag xxhash(menu_items)
+    menu_items_json
 end