Add completed flag to only publish the grade once

drag_and_drop_v2/drag_and_drop_v2.py

@@ -10,7 +10,7 @@ import copy
 import urllib
 
 from xblock.core import XBlock
-from xblock.fields import Scope, String, Dict, Float
+from xblock.fields import Scope, String, Dict, Float, Boolean
 from xblock.fragment import Fragment
 
 from .utils import render_template, load_resource
@@ -62,6 +62,12 @@ class DragAndDropBlock(XBlock):
         default={}
     )
 
+    completed = Boolean(
+        help="The student has completed the problem at least once",
+        scope=Scope.user_state,
+        default=False
+    )
+
     has_score = True
 
     def student_view(self, context):
@@ -173,6 +179,9 @@ class DragAndDropBlock(XBlock):
             if self._is_finished():
                 final_feedback = self.data['feedback']['finish']
 
+            # only publish the grade once
+            if not self.completed:
+                self.completed = True
                 try:
                     self.runtime.publish(self, 'grade', {
                         'value': len(self.item_state) / float(tot_items) * self.weight,