Fix lis_outcome_service_url sending.

common/djangoapps/student/models.py

@@ -46,8 +46,8 @@ class AnonymousUserId(models.Model):
 
     Purpose of this table is to provide user by anonymous_user_id.
 
-    We are generating anonymous_user_id using md5 algorithm, so resulting length will always be 16 bytes.
-    http://docs.python.org/2/library/md5.html#md5.digest_size
+    We generate anonymous_user_id using md5 algorithm,
+    and use result in hex form, so its length is equal to 32 bytes.
     """
     user = models.ForeignKey(User, db_index=True)
     anonymous_user_id = models.CharField(unique=True, max_length=32)

common/lib/xmodule/xmodule/lti_module.py

@@ -355,11 +355,15 @@ class LTIModule(LTIFields, XModule):
 
             # Parameters required for grading:
             u'resource_link_id': self.get_resource_link_id(),
-            u'lis_outcome_service_url': self.get_outcome_service_url(),
             u'lis_result_sourcedid': self.get_lis_result_sourcedid(),
 
         }
 
+        if self.has_score:
+            body.update({
+                u'lis_outcome_service_url': self.get_outcome_service_url()
+            })
+
         # Appending custom parameter for signing.
         body.update(custom_parameters)
 
@@ -483,6 +487,8 @@ oauth_consumer_key="", oauth_signature="frVp4JuvT1mVXlxktiAUjQ7%2F1cw%3D"'}
         try:
             imsx_messageIdentifier, sourcedId, score, action = self.parse_grade_xml_body(request.body)
         except Exception:
+            log.debug("[LTI]: Request body XML parsing error.")
+            failure_values['imsx_description'] = 'Request body XML parsing error.'
             return Response(response_xml_template.format(**failure_values), content_type="application/xml")
 
         # Verify OAuth signing.
@@ -490,10 +496,15 @@ oauth_consumer_key="", oauth_signature="frVp4JuvT1mVXlxktiAUjQ7%2F1cw%3D"'}
             self.verify_oauth_body_sign(request)
         except (ValueError, LTIError):
             failure_values['imsx_messageIdentifier'] = escape(imsx_messageIdentifier)
+            failure_values['imsx_description'] = 'OAuth verification error.'
             return Response(response_xml_template.format(**failure_values), content_type="application/xml")
 
-
         real_user = self.system.get_real_user(urllib.unquote(sourcedId.split(':')[-1]))
+        if not real_user:  # that means we can't save to database, as we do not have real user id.
+            failure_values['imsx_messageIdentifier'] = escape(imsx_messageIdentifier)
+            failure_values['imsx_description'] = 'User not found.'
+            return Response(response_xml_template.format(**failure_values), content_type="application/xml")
+
         if action == 'replaceResultRequest':
             self.system.publish(
                 event={
@@ -510,9 +521,11 @@ oauth_consumer_key="", oauth_signature="frVp4JuvT1mVXlxktiAUjQ7%2F1cw%3D"'}
                 'imsx_messageIdentifier': escape(imsx_messageIdentifier),
                 'response': '<replaceResultResponse/>'
             }
+            log.debug("[LTI]: Grade is saved.")
             return Response(response_xml_template.format(**values), content_type="application/xml")
 
         unsupported_values['imsx_messageIdentifier'] = escape(imsx_messageIdentifier)
+        log.debug("[LTI]: Incorrect action.")
         return Response(response_xml_template.format(**unsupported_values), content_type='application/xml')
 
 
@@ -541,6 +554,7 @@ oauth_consumer_key="", oauth_signature="frVp4JuvT1mVXlxktiAUjQ7%2F1cw%3D"'}
         # Raise exception if score is not float or not in range 0.0-1.0 regarding spec.
         score = float(score)
         if not 0 <= score <= 1:
+            log.debug("[LTI]: Score not in range.")
             raise LTIError
 
         return imsx_messageIdentifier, sourcedId, score, action
@@ -582,8 +596,11 @@ oauth_consumer_key="", oauth_signature="frVp4JuvT1mVXlxktiAUjQ7%2F1cw%3D"'}
             params=oauth_headers.items(),
             signature=oauth_signature
         )
-        if (oauth_body_hash != oauth_headers.get('oauth_body_hash') or
-            not signature.verify_hmac_sha1(mock_request, client_secret)):
+        if oauth_body_hash != oauth_headers.get('oauth_body_hash'):
+            log.debug("[LTI]: OAuth body hash verification is failed.")
+            raise LTIError
+        if not signature.verify_hmac_sha1(mock_request, client_secret):
+            log.debug("[LTI]: OAuth signature verification is failed.")
             raise LTIError
 
     def get_client_key_secret(self):

common/lib/xmodule/xmodule/tests/test_lti_unit.py

@@ -112,7 +112,7 @@ class LTIModuleTest(LogicTest):
         expected_response = {
             'action': None,
             'code_major': 'failure',
-            'description': 'The request has failed.',
+            'description': 'OAuth verification error.',
             'messageIdentifier': self.DEFAULTS['messageIdentifier'],
         }
 
@@ -133,7 +133,27 @@ class LTIModuleTest(LogicTest):
         expected_response = {
             'action': None,
             'code_major': 'failure',
-            'description': 'The request has failed.',
+            'description': 'OAuth verification error.',
+            'messageIdentifier': self.DEFAULTS['messageIdentifier'],
+        }
+        self.assertEqual(response.status_code, 200)
+        self.assertDictEqual(expected_response, real_response)
+
+    def test_real_user_is_none(self):
+        """
+        If we have no real user, we should send back failure response.
+        """
+        self.xmodule.verify_oauth_body_sign = Mock()
+        self.xmodule.has_score = True
+        self.system.get_real_user = Mock(return_value=None)
+        request = Request(self.environ)
+        request.body = self.get_request_body()
+        response = self.xmodule.grade_handler(request, '')
+        real_response = self.get_response_values(response)
+        expected_response = {
+            'action': None,
+            'code_major': 'failure',
+            'description': 'User not found.',
             'messageIdentifier': self.DEFAULTS['messageIdentifier'],
         }
         self.assertEqual(response.status_code, 200)
@@ -151,7 +171,7 @@ class LTIModuleTest(LogicTest):
         expected_response = {
             'action': None,
             'code_major': 'failure',
-            'description': 'The request has failed.',
+            'description': 'Request body XML parsing error.',
             'messageIdentifier': 'unknown',
         }
         self.assertEqual(response.status_code, 200)
@@ -169,7 +189,7 @@ class LTIModuleTest(LogicTest):
         expected_response = {
             'action': None,
             'code_major': 'failure',
-            'description': 'The request has failed.',
+            'description': 'Request body XML parsing error.',
             'messageIdentifier': 'unknown',
         }
         self.assertEqual(response.status_code, 200)

common/lib/xmodule/xmodule/x_module.py

@@ -1016,6 +1016,9 @@ class ModuleSystem(ConfigurableFragmentWrapper, Runtime):  # pylint: disable=abs
 
         error_descriptor_class - The class to use to render XModules with errors
 
+        get_real_user - function that takes `anonymous_student_id` and returns real user_id,
+        associated with `anonymous_student_id`.
+
         """
 
         # Right now, usage_store is unused, and field_data is always supplanted