Add docstring to 'score_update' path

common/lib/capa/capa/capa_problem.py

@@ -180,9 +180,15 @@ class LoncapaProblem(object):
                     'total': self.get_max_score()}
 
     def update_score(self, score_msg):
+        '''
+        Deliver grading response (e.g. from async code checking) to 
+            the specific ResponseType
+         
+        Returns an updated CorrectMap
+        '''
         newcmap = CorrectMap()
         for responder in self.responders.values():
-            if hasattr(responder,'update_score'): # Is this the best way to implement 'update_score' for CodeResponse?
+            if hasattr(responder,'update_score'): # TODO: Is this the best way to target 'update_score' of CodeResponse?
                 results = responder.update_score(score_msg)         
                 newcmap.update(results)
         self.correct_map = newcmap

common/lib/capa/capa/responsetypes.py

@@ -696,7 +696,9 @@ class SymbolicResponse(CustomResponse):
 
 class CodeResponse(LoncapaResponse):
     ''' 
-    Grade student code using an external server
+    Grade student code using an external server. Unlike ExternalResponse, CodeResponse:
+        1) Goes through a queueing system (xqueue)
+        2) Does not do external request for 'get_answers'
     '''
 
     response_tag = 'coderesponse'
@@ -704,9 +706,10 @@ class CodeResponse(LoncapaResponse):
 
     def setup_response(self):
         xml = self.xml
-        self.url = xml.get('url') or "http://ec2-50-16-59-149.compute-1.amazonaws.com/xqueue/submit/" # FIXME -- hardcoded url
+        self.url = xml.get('url', "http://ec2-50-16-59-149.compute-1.amazonaws.com/xqueue/submit/") # FIXME -- hardcoded url
 
         answer = xml.find('answer')
+
         if answer is not None:
             answer_src = answer.get('src')
             if answer_src is not None:
@@ -791,7 +794,9 @@ class CodeResponse(LoncapaResponse):
         # Prepare payload
         xmlstr = etree.tostring(self.xml, pretty_print=True)
         header = { 'return_url': self.system.xqueue_callback_url }
-        header.update({'timestamp': time.time()})
+#        header.update({'timestamp': time.time()})
+        random.seed()
+        header.update({'key': random.randint(0,2**32-1)})
         payload = {'xqueue_header': json.dumps(header), # 'xqueue_header' should eventually be derived from xqueue.queue_common.HEADER_TAG or something similar
                    'xml': xmlstr,
                    'edX_cmd': 'get_score',

common/lib/xmodule/xmodule/capa_module.py

@@ -323,6 +323,15 @@ class CapaModule(XModule):
         raise self.system.exception404
 
     def update_score(self, get):
+        """
+        Delivers grading response (e.g. from asynchronous code checking) to
+            the capa problem, so its score can be updated
+
+        'get' must have a field 'response' which is a string that contains the
+            grader's response
+
+        No ajax return is needed. Return empty dict.
+        """
         score_msg = get['response']
         self.lcp.update_score(score_msg)