add sort direction support

app/api/mobile/apis/project_packages.rb

@@ -21,6 +21,7 @@ module Mobile
           optional :category, type: String, desc: '类型'
           optional :keyword, type: String, desc: '搜索关键字'
           optional :sort_by, type: String, desc: '排序'
+          optional :sort_direction, type: String, desc: '排序方向'
           optional :page, type: Integer, desc: '页数'
           optional :per_page, type: Integer, desc: '分页大小'
         end
@@ -34,11 +35,10 @@ module Mobile
 
           count = packages.count
 
-          if params[:sort_by] == 'price'
-            packages = packages.order('min_price desc')
-          else
-            packages = packages.order('published_at desc')
-          end
+          direction = params[:sort_direction] == 'asc' ? 'asc' : 'desc'
+          sort      = params[:sort_by] == 'price' ? 'min_price' : 'published_at'
+          packages  = packages.order("#{sort} #{direction}")
+
           packages = paginate packages.includes(:creator, :attachments, bidding_users: :user)
 
           present :count, count