Show a friendlier error message when the submission API reports a request error

Show a more specific error message for answer too long errors

openassessment/xblock/submission_mixin.py

@@ -26,14 +26,15 @@ class SubmissionMixin(object):
 
     """
 
-    submit_errors = {
+    SUBMIT_ERRORS = {
         # Reported to user sometimes, and useful in tests
-        'ENODATA':  _(u'API returned an empty response.'),
-        'EBADFORM': _(u'API Submission Request Error.'),
-        'EUNKNOWN': _(u'API returned unclassified exception.'),
+        'ENODATA':  _(u'An unexpected error occurred.'),
+        'EBADFORM': _(u'An unexpected error occurred.'),
+        'EUNKNOWN': _(u'An unexpected error occurred.'),
         'ENOMULTI': _(u'Multiple submissions are not allowed.'),
         'ENOPREVIEW': _(u'To submit a response, view this component in Preview or Live mode.'),
-        'EBADARGS': _(u'"submission" required to submit answer.')
+        'EBADARGS': _(u'An unexpected error occurred.'),
+        'EANSWERLENGTH': _(u'This response exceeds the size limit.')
     }
 
     @XBlock.json_handler
@@ -57,7 +58,7 @@ class SubmissionMixin(object):
 
         """
         if 'submission' not in data:
-            return False, 'EBADARGS', self.submit_errors['EBADARGS']
+            return False, 'EBADARGS', self.SUBMIT_ERRORS['EBADARGS']
 
         status = False
         status_text = None
@@ -67,7 +68,7 @@ class SubmissionMixin(object):
         # Short-circuit if no user is defined (as in Studio Preview mode)
         # Since students can't submit, they will never be able to progress in the workflow
         if self.in_studio_preview:
-            return False, 'ENOPREVIEW', self.submit_errors['ENOPREVIEW']
+            return False, 'ENOPREVIEW', self.SUBMIT_ERRORS['ENOPREVIEW']
 
         workflow = self.get_workflow_info()
 
@@ -80,10 +81,35 @@ class SubmissionMixin(object):
                     student_sub
                 )
             except api.SubmissionRequestError as err:
-                status_tag = 'EBADFORM'
-                status_text = unicode(err.field_errors)
+
+                # Handle the case of an answer that's too long as a special case,
+                # so we can display a more specific error message.
+                # Although we limit the number of characters the user can
+                # enter on the client side, the submissions API uses the JSON-serialized
+                # submission to calculate length.  If each character submitted
+                # by the user takes more than 1 byte to encode (for example, double-escaped
+                # newline characters or non-ASCII unicode), then the user might
+                # exceed the limits set by the submissions API.  In that case,
+                # we display an error message indicating that the answer is too long.
+                answer_too_long = any(
+                    "maximum answer size exceeded" in answer_err.lower()
+                    for answer_err in err.field_errors.get('answer', [])
+                )
+                if answer_too_long:
+                    status_tag = 'EANSWERLENGTH'
+                else:
+                    msg = (
+                        u"The submissions API reported an invalid request error "
+                        u"when submitting a response for the user: {student_item}"
+                    ).format(student_item=student_item_dict)
+                    logger.exception(msg)
+                    status_tag = 'EBADFORM'
             except (api.SubmissionError, AssessmentWorkflowError):
-                logger.exception("This response was not submitted.")
+                msg = (
+                    u"An unknown error occurred while submitting "
+                    u"a response for the user: {student_item}"
+                ).format(student_item=student_item_dict)
+                logger.exception(msg)
                 status_tag = 'EUNKNOWN'
             else:
                 status = True
@@ -91,7 +117,7 @@ class SubmissionMixin(object):
                 status_text = submission.get('attempt_number')
 
         # relies on success being orthogonal to errors
-        status_text = status_text if status_text else self.submit_errors[status_tag]
+        status_text = status_text if status_text else self.SUBMIT_ERRORS[status_tag]
         return status, status_tag, status_text
 
     @XBlock.json_handler

openassessment/xblock/test/test_submission.py

@@ -9,7 +9,6 @@ import pytz
 from mock import patch, Mock
 from submissions import api as sub_api
 from submissions.api import SubmissionRequestError, SubmissionInternalError
-from openassessment.xblock.submission_mixin import SubmissionMixin
 from .base import XBlockHandlerTestCase, scenario
 
 
@@ -23,6 +22,17 @@ class SubmissionTest(XBlockHandlerTestCase):
         self.assertTrue(resp[0])
 
     @scenario('data/basic_scenario.xml', user_id='Bob')
+    def test_submit_answer_too_long(self, xblock):
+        # Maximum answer length is 100K, once the answer has been JSON-encoded
+        long_submission = json.dumps({
+            'submission': 'longcat is long ' * 100000
+        })
+        resp = self.request(xblock, 'submit', long_submission, response_format='json')
+        self.assertFalse(resp[0])
+        self.assertEqual(resp[1], "EANSWERLENGTH")
+        self.assertEqual(resp[2], xblock.SUBMIT_ERRORS["EANSWERLENGTH"])
+
+    @scenario('data/basic_scenario.xml', user_id='Bob')
     def test_submission_multisubmit_failure(self, xblock):
         # We don't care about return value of first one
         self.request(xblock, 'submit', self.SUBMISSION, response_format='json')
@@ -31,7 +41,7 @@ class SubmissionTest(XBlockHandlerTestCase):
         resp = self.request(xblock, 'submit', self.SUBMISSION, response_format='json')
         self.assertFalse(resp[0])
         self.assertEqual(resp[1], "ENOMULTI")
-        self.assertEqual(resp[2], xblock.submit_errors["ENOMULTI"])
+        self.assertEqual(resp[2], xblock.SUBMIT_ERRORS["ENOMULTI"])
 
     @scenario('data/basic_scenario.xml', user_id='Bob')
     @patch.object(sub_api, 'create_submission')
@@ -40,15 +50,16 @@ class SubmissionTest(XBlockHandlerTestCase):
         resp = self.request(xblock, 'submit', self.SUBMISSION, response_format='json')
         self.assertFalse(resp[0])
         self.assertEqual(resp[1], "EUNKNOWN")
-        self.assertEqual(resp[2], SubmissionMixin().submit_errors["EUNKNOWN"])
+        self.assertEqual(resp[2], xblock.SUBMIT_ERRORS["EUNKNOWN"])
 
     @scenario('data/basic_scenario.xml', user_id='Bob')
     @patch.object(sub_api, 'create_submission')
     def test_submission_API_failure(self, xblock, mock_submit):
-        mock_submit.side_effect = SubmissionRequestError("Cat on fire.")
+        mock_submit.side_effect = SubmissionRequestError(msg="Cat on fire.")
         resp = self.request(xblock, 'submit', self.SUBMISSION, response_format='json')
         self.assertFalse(resp[0])
         self.assertEqual(resp[1], "EBADFORM")
+        self.assertEqual(resp[2], xblock.SUBMIT_ERRORS["EBADFORM"])
 
     # In Studio preview mode, the runtime sets the user ID to None
     @scenario('data/basic_scenario.xml', user_id=None)
@@ -65,7 +76,7 @@ class SubmissionTest(XBlockHandlerTestCase):
         resp = self.request(xblock, 'submit', self.SUBMISSION, response_format='json')
         self.assertFalse(resp[0])
         self.assertEqual(resp[1], "ENOPREVIEW")
-        self.assertEqual(resp[2], "To submit a response, view this component in Preview or Live mode.")
+        self.assertEqual(resp[2], xblock.SUBMIT_ERRORS["ENOPREVIEW"])
 
     @scenario('data/over_grade_scenario.xml', user_id='Alice')
     def test_closed_submissions(self, xblock):

requirements/base.txt

@@ -6,7 +6,7 @@
 git+https://github.com/edx/XBlock.git@fc5fea25c973ec66d8db63cf69a817ce624f5ef5#egg=XBlock
 git+https://github.com/edx/xblock-sdk.git@643900aadcb18aaeb7fe67271ca9dbf36e463ee6#egg=xblock-sdk
 
-edx-submissions==0.0.3
+edx-submissions==0.0.5
 
 # Third Party Requirements
 boto==2.13.3