Move query notes by user value to mixin

app/controllers/api/notes_controller.rb

@@ -256,19 +256,8 @@ module Api
       @notes = bbox_condition(@notes)
 
       # Add any user filter
-      if params[:display_name] || params[:user]
-        if params[:display_name]
-          @user = User.find_by(:display_name => params[:display_name])
-
-          raise OSM::APIBadUserInput, "User #{params[:display_name]} not known" unless @user
-        else
-          @user = User.find_by(:id => params[:user])
-
-          raise OSM::APIBadUserInput, "User #{params[:user]} not known" unless @user
-        end
-
-        @notes = @notes.joins(:comments).where(:note_comments => { :author_id => @user })
-      end
+      user = query_conditions_user_value
+      @notes = @notes.joins(:comments).where(:note_comments => { :author_id => user }) if user
 
       # Add any text filter
       if params[:q]

app/controllers/concerns/query_methods.rb

@@ -3,6 +3,33 @@ module QueryMethods
 
   private
 
+  ##
+  # Filter the resulting items by user
+  def query_conditions_user(items, filter_property)
+    user = query_conditions_user_value
+    items = items.where(filter_property => user) if user
+    items
+  end
+
+  ##
+  # Get user value for query filtering by user
+  # Raises OSM::APIBadUserInput if user not found like notes api does, changesets api raises OSM::APINotFoundError instead
+  def query_conditions_user_value
+    if params[:display_name] || params[:user]
+      if params[:display_name]
+        user = User.find_by(:display_name => params[:display_name])
+
+        raise OSM::APIBadUserInput, "User #{params[:display_name]} not known" unless user
+      else
+        user = User.find_by(:id => params[:user])
+
+        raise OSM::APIBadUserInput, "User #{params[:user]} not known" unless user
+      end
+
+      user
+    end
+  end
+
   ##
   # Restrict the resulting items to those created during a particular time period
   # Using 'to' requires specifying 'from' as well for historical reasons