paging done, needs some additional refactoring

front-api/app.rb

@@ -16,6 +16,7 @@ before do
   headers 'Access-Control-Allow-Origin' => 'http://localhost:3001',
     'Access-Control-Allow-Methods' => ['OPTIONS', 'GET', 'POST','PUT'],
     'Access-Control-Allow-Headers' => 'Origin, X-Requested-With, Content-Type, Accept',
+    'Access-Control-Expose-Headers' => 'X-Total-Count',
     'Access-Control-Allow-Credentials' => 'true'
 
   request.body.rewind

front-api/controllers/common_for_controllers.rb

@@ -3,6 +3,10 @@ def get_querystring_hash()
    Rack::Utils.parse_nested_query(request.query_string)
 end
 
+def add_total_count_header(total)
+  response.headers['X-Total-Count'] = total
+end
+
 # converts list of parameters to array of integers
 def mass_to_i(*id_strings)
   id_strings.map(&:to_i)

front-api/controllers/item.rb

@@ -21,7 +21,7 @@ end
 
 def filter_by_traits(items)
   get_querystring_hash.each do |k,v|
-    items = items.where(["traits ->> '#{k}' = '#{v}'"])
+    items = items.where(["traits ->> ? = ?", k, v])
   end
   items
 end
@@ -54,9 +54,12 @@ get '/item/category/:category_id/offset/:offset/limit/:limit' do |category_id_s,
   input_invalid = offset_and_limit_invalid?(offset,limit) or category_id <= 0
   return [].to_json if input_invalid 
 
+  all_in_cat = filter_by_traits(Item.all_in_category(category_id))
   items = Item.best_selling_in_category(category_id, offset,limit)
   items = filter_by_traits(items)
 
+  add_total_count_header(all_in_cat.count)
+
   prepare_items_for_mass_display(items)
 end
 

front-api/models/item.rb

@@ -10,7 +10,13 @@ class Item < ActiveRecord::Base
 
   # TODO: change "best selling" algorithm when get some data - currently it's only sorted by earnings
   scope :best_selling, -> (offset, limit) { where(:on_display => true).order("(list_price - current_input_price) DESC").limit(limit).offset(offset) }
+
   scope :best_selling_in_sub_category, -> (sub_category_id, offset, limit) {  best_selling(offset, limit).where(sub_category_id: sub_category_id) }
+
   scope :best_selling_in_category, -> (category_id, offset, limit) {  best_selling(offset, limit).joins( sub_category: [:category] ).where(["category_id = ?", category_id]) }
+
   scope :best_selling_in_section, -> (section_id, offset, limit) {  best_selling(offset, limit).joins( sub_category: [category: [ :section ]] ).where( ["section_id = ?", section_id] ) }
+
+  scope :all_in_category, -> (category_id) { where(on_display: true).joins( sub_category: [:category]).where(["category_id = ?", category_id]) }
+
 end

front-api/models/sub_category.rb

@@ -1,6 +1,7 @@
 class SubCategory < ActiveRecord::Base
   belongs_to :category
   has_many :filter_criterias, as: :owner
+  has_many :items
 end