Moves changed since condition to scope

app/controllers/api/v2/planning_elements_controller.rb

@@ -38,6 +38,7 @@ module Api
 
       before_filter :find_project_by_project_id,
                     :authorize, :except => [:index]
+      before_filter :parse_changed_since, only: [:index]
       before_filter :assign_planning_elements, :except => [:index, :update, :create]
 
       # Attention: find_all_projects_by_project_id needs to mimic all of the above
@@ -207,13 +208,9 @@ module Api
 
       def current_work_packages(projects)
         work_packages = WorkPackage.for_projects(projects)
+                                   .changed_since(@since)
                                    .includes(:status, :project, :type)
 
-        if params[:changed_since]
-          since = Time.at(Float(params[:changed_since]).to_i) rescue render_400
-          work_packages = work_packages.where(["updated_at >= ?", since])
-        end
-
         if params[:f]
           query = Query.new
           query.add_filters(params[:f], params[:op], params[:v])
@@ -283,6 +280,14 @@ module Api
 
 
       end
+
+      private
+
+      def parse_changed_since
+        if params[:changed_since]
+          @since = Time.at(Float(params[:changed_since]).to_i) rescue render_400
+        end
+      end
     end
   end
 end

app/models/work_package.rb

@@ -78,6 +78,10 @@ class WorkPackage < ActiveRecord::Base
     {:conditions => {:project_id => projects}}
   }
 
+  scope :changed_since, lambda { |changed_since|
+    changed_since ? { conditions: ["updated_at >= ?", changed_since] } : nil
+  }
+
   # >>> issues.rb >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
   scope :open, :conditions => ["#{Status.table_name}.is_closed = ?", false], :include => :status