Allow JSON-serializable answers

apps/openassessment/templates/openassessmentblock/grade/oa_grade_complete.html

@@ -19,7 +19,7 @@
                 <h3 class="submission__answer__display__title">Your Submitted Response</h3>
 
                 <div class="submission__answer__display__content">
-                    {{ student_submission.answer }}
+                    {{ student_submission.answer.text|linebreaks }}
                 </div>
             </article>
 

apps/openassessment/templates/openassessmentblock/peer/oa_peer_assessment.html

@@ -56,7 +56,7 @@
                                 </header>
 
                                 <div class="peer-assessment__display__response">
-                                    {{ peer_submission.answer|linebreaks }}
+                                    {{ peer_submission.answer.text|linebreaks }}
                                 </div>
                             </div>
 

apps/openassessment/templates/openassessmentblock/response/oa_response_graded.html

@@ -22,7 +22,7 @@
                 <h3 class="submission__answer__display__title">Your Submitted Response</h3>
 
                 <div class="submission__answer__display__content">
-                    {{ student_submission.answer|linebreaks }}
+                    {{ student_submission.answer.text|linebreaks }}
                 </div>
             </article>
         </div>

apps/openassessment/templates/openassessmentblock/response/oa_response_submitted.html

@@ -22,7 +22,7 @@
                 <h3 class="submission__answer__display__title">Your Submitted Response</h3>
 
                 <div class="submission__answer__display__content">
-                    {{ student_submission.answer|linebreaks }}
+                    {{ student_submission.answer.text|linebreaks }}
                 </div>
             </article>
         </div>

apps/openassessment/templates/openassessmentblock/self/oa_self_assessment.html

@@ -39,7 +39,7 @@
                     </header>
 
                     <div class="self-assessment__display__response">
-                        {{ self_submission.answer|linebreaks }}
+                        {{ self_submission.answer.text|linebreaks }}
                     </div>
                 </article>
 

apps/openassessment/xblock/submission_mixin.py

@@ -112,7 +112,12 @@ class SubmissionMixin(object):
             return {'success': False, 'msg': _(u"Missing required key 'submission'")}
 
     def create_submission(self, student_item_dict, student_sub):
-        submission = api.create_submission(student_item_dict, student_sub)
+
+        # Store the student's response text in a JSON-encodable dict
+        # so that later we can add additional response fields.
+        student_sub_dict = {'text': student_sub}
+
+        submission = api.create_submission(student_item_dict, student_sub_dict)
         workflow = workflow_api.create_workflow(submission["uuid"])
         self.submission_uuid = submission["uuid"]
         return submission

apps/openassessment/xblock/test/test_peer.py

@@ -68,13 +68,11 @@ class TestPeerAssessment(XBlockHandlerTestCase):
         request.params = {}
         peer_response = xblock.render_peer_assessment(request)
         self.assertIsNotNone(peer_response)
-        self.assertNotIn(submission["answer"].encode('utf-8'), peer_response.body)
+        self.assertNotIn(submission["answer"]["text"].encode('utf-8'), peer_response.body)
 
         #Validate Peer Rendering.
         self.assertIn("Sally".encode('utf-8'), peer_response.body)
 
-
-
     @scenario('data/peer_assessment_scenario.xml', user_id='Bob')
     def test_assess_handler(self, xblock):
 

apps/submissions/admin.py

@@ -5,7 +5,7 @@ from submissions.models import Score, StudentItem, Submission
 class SubmissionAdmin(admin.ModelAdmin):
     list_display = (
         'student_item', 'uuid', 'attempt_number', 'submitted_at', 'created_at',
-        'answer', 'scores'
+        'raw_answer', 'scores'
     )
 
     def scores(self, obj):

apps/submissions/api.py

@@ -8,7 +8,9 @@ import logging
 from django.db import DatabaseError
 from django.utils.encoding import force_unicode
 
-from submissions.serializers import SubmissionSerializer, StudentItemSerializer, ScoreSerializer
+from submissions.serializers import (
+    SubmissionSerializer, StudentItemSerializer, ScoreSerializer, JsonFieldError
+)
 from submissions.models import Submission, StudentItem, Score, ScoreSummary
 
 logger = logging.getLogger(__name__)
@@ -67,7 +69,7 @@ def create_submission(student_item_dict, answer, submitted_at=None,
         student_item_dict (dict): The student_item this
             submission is associated with. This is used to determine which
             course, student, and location this submission belongs to.
-        answer (str): The answer given by the student to be assessed.
+        answer (JSON-serializable): The answer given by the student to be assessed.
         submitted_at (datetime): The date in which this submission was submitted.
             If not specified, defaults to the current date.
         attempt_number (int): A student may be able to submit multiple attempts
@@ -122,12 +124,6 @@ def create_submission(student_item_dict, answer, submitted_at=None,
             raise SubmissionInternalError(error_message)
         attempt_number = submissions[0].attempt_number + 1 if submissions else 1
 
-    try:
-        answer = force_unicode(answer)
-    except UnicodeDecodeError:
-        raise SubmissionRequestError(
-            u"Submission answer could not be properly decoded to unicode.")
-
     model_kwargs = {
         "student_item": student_item_model.pk,
         "answer": answer,
@@ -143,6 +139,11 @@ def create_submission(student_item_dict, answer, submitted_at=None,
         submission_serializer.save()
 
         return submission_serializer.data
+    except JsonFieldError:
+        error_message = u"Could not serialize JSON field in submission {} for student item {}".format(
+            model_kwargs, student_item_dict
+        )
+        raise SubmissionRequestError(error_message)
     except DatabaseError:
         error_message = u"An error occurred while creating submission {} for student item: {}".format(
             model_kwargs,
@@ -181,6 +182,7 @@ def get_submission(submission_uuid):
 
     try:
         submission = Submission.objects.get(uuid=submission_uuid)
+        return SubmissionSerializer(submission).data
     except Submission.DoesNotExist:
         raise SubmissionNotFoundError(
             u"No submission matching uuid {}".format(submission_uuid)
@@ -191,8 +193,6 @@ def get_submission(submission_uuid):
         logger.exception(err_msg)
         raise SubmissionInternalError(err_msg)
 
-    return SubmissionSerializer(submission).data
-
 
 def get_submission_and_student(uuid):
     """
@@ -211,8 +211,13 @@ def get_submission_and_student(uuid):
         return None
 
     # There is probably a more idiomatic way to do this using the Django REST framework
-    submission_dict = SubmissionSerializer(submission).data
-    submission_dict['student_item'] = StudentItemSerializer(submission.student_item).data
+    try:
+        submission_dict = SubmissionSerializer(submission).data
+        submission_dict['student_item'] = StudentItemSerializer(submission.student_item).data
+    except Exception as ex:
+        err_msg = "Could not get submission due to error: {}".format(ex)
+        logger.exception(err_msg)
+        raise SubmissionInternalError(err_msg)
 
     return submission_dict
 

apps/submissions/migrations/0003_auto__del_field_submission_answer__add_field_submission_raw_answer.py

+# -*- coding: utf-8 -*-
+import datetime
+from south.db import db
+from south.v2 import SchemaMigration
+from django.db import models
+
+
+class Migration(SchemaMigration):
+
+    def forwards(self, orm):
+        # Deleting field 'Submission.answer'
+        db.delete_column('submissions_submission', 'answer')
+
+        # Adding field 'Submission.raw_answer'
+        db.add_column('submissions_submission', 'raw_answer',
+                      self.gf('django.db.models.fields.TextField')(default='', blank=True),
+                      keep_default=False)
+
+
+    def backwards(self, orm):
+        # Adding field 'Submission.answer'
+        db.add_column('submissions_submission', 'answer',
+                      self.gf('django.db.models.fields.TextField')(default='', blank=True),
+                      keep_default=False)
+
+        # Deleting field 'Submission.raw_answer'
+        db.delete_column('submissions_submission', 'raw_answer')
+
+
+    models = {
+        'submissions.score': {
+            'Meta': {'object_name': 'Score'},
+            'created_at': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now', 'db_index': 'True'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'points_earned': ('django.db.models.fields.PositiveIntegerField', [], {'default': '0'}),
+            'points_possible': ('django.db.models.fields.PositiveIntegerField', [], {'default': '0'}),
+            'student_item': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['submissions.StudentItem']"}),
+            'submission': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['submissions.Submission']", 'null': 'True'})
+        },
+        'submissions.scoresummary': {
+            'Meta': {'object_name': 'ScoreSummary'},
+            'highest': ('django.db.models.fields.related.ForeignKey', [], {'related_name': "'+'", 'to': "orm['submissions.Score']"}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'latest': ('django.db.models.fields.related.ForeignKey', [], {'related_name': "'+'", 'to': "orm['submissions.Score']"}),
+            'student_item': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['submissions.StudentItem']", 'unique': 'True'})
+        },
+        'submissions.studentitem': {
+            'Meta': {'unique_together': "(('course_id', 'student_id', 'item_id'),)", 'object_name': 'StudentItem'},
+            'course_id': ('django.db.models.fields.CharField', [], {'max_length': '255', 'db_index': 'True'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'item_id': ('django.db.models.fields.CharField', [], {'max_length': '255', 'db_index': 'True'}),
+            'item_type': ('django.db.models.fields.CharField', [], {'max_length': '100'}),
+            'student_id': ('django.db.models.fields.CharField', [], {'max_length': '255', 'db_index': 'True'})
+        },
+        'submissions.submission': {
+            'Meta': {'ordering': "['-submitted_at', '-id']", 'object_name': 'Submission'},
+            'attempt_number': ('django.db.models.fields.PositiveIntegerField', [], {}),
+            'created_at': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now', 'db_index': 'True'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'raw_answer': ('django.db.models.fields.TextField', [], {'blank': 'True'}),
+            'student_item': ('django.db.models.fields.related.ForeignKey', [], {'to': "orm['submissions.StudentItem']"}),
+            'submitted_at': ('django.db.models.fields.DateTimeField', [], {'default': 'datetime.datetime.now', 'db_index': 'True'}),
+            'uuid': ('django.db.models.fields.CharField', [], {'db_index': 'True', 'max_length': '36', 'blank': 'True'})
+        }
+    }
+
+    complete_apps = ['submissions']
\ No newline at end of file

apps/submissions/models.py

@@ -9,6 +9,7 @@ need to then generate a matching migration for it using:
     ./manage.py schemamigration submissions --auto
 
 """
+import json
 import logging
 
 from django.db import models, DatabaseError
@@ -84,8 +85,8 @@ class Submission(models.Model):
     # When this row was created.
     created_at = models.DateTimeField(editable=False, default=now, db_index=True)
 
-    # The actual answer, assumed to be a JSON string
-    answer = models.TextField(blank=True)
+    # The answer (JSON-serialized)
+    raw_answer = models.TextField(blank=True)
 
     def __repr__(self):
         return repr(dict(
@@ -94,7 +95,7 @@ class Submission(models.Model):
             attempt_number=self.attempt_number,
             submitted_at=self.submitted_at,
             created_at=self.created_at,
-            answer=self.answer,
+            raw_answer=self.raw_answer,
         ))
 
     class Meta:

apps/submissions/serializers.py

@@ -2,10 +2,59 @@
 Serializers are created to ensure models do not have to be accessed outside the
 scope of the Tim APIs.
 """
+import json
 from rest_framework import serializers
 from submissions.models import StudentItem, Submission, Score
 
 
+class JsonFieldError(Exception):
+    """
+    An error occurred while serializing/deserializing JSON.
+    """
+    pass
+
+
+class JsonField(serializers.WritableField):
+    """
+    JSON-serializable field.
+    """
+    def to_native(self, obj):
+        """
+        Deserialize the JSON string.
+
+        Args:
+            obj (str): The JSON string stored in the database.
+
+        Returns:
+            JSON-serializable
+
+        Raises:
+            JsonFieldError: The field could not be deserialized.
+        """
+        try:
+            return json.loads(obj)
+        except (TypeError, ValueError):
+            raise JsonFieldError(u"Could not deserialize as JSON: {}".format(obj))
+
+    def from_native(self, data):
+        """
+        Serialize an object to JSON.
+
+        Args:
+            data (JSON-serializable): The data to serialize.
+
+        Returns:
+            str
+
+        Raises:
+            ValueError: The data could not be serialized as JSON.
+        """
+        try:
+            return json.dumps(data)
+        except (TypeError, ValueError):
+            raise JsonFieldError(u"Could not serialize as JSON: {}".format(data))
+
+
 class StudentItemSerializer(serializers.ModelSerializer):
     class Meta:
         model = StudentItem
@@ -14,6 +63,8 @@ class StudentItemSerializer(serializers.ModelSerializer):
 
 class SubmissionSerializer(serializers.ModelSerializer):
 
+    answer = JsonField(source='raw_answer')
+
     class Meta:
         model = Submission
         fields = (
@@ -22,6 +73,8 @@ class SubmissionSerializer(serializers.ModelSerializer):
             'attempt_number',
             'submitted_at',
             'created_at',
+
+            # Computed
             'answer',
         )
 

apps/submissions/tests/test_api.py

@@ -41,6 +41,7 @@ class TestSubmissionsApi(TestCase):
         student_item = self._get_student_item(STUDENT_ITEM)
         self._assert_submission(submission, ANSWER_ONE, student_item.pk, 1)
 
+
     def test_get_submission_and_student(self):
         submission = api.create_submission(STUDENT_ITEM, ANSWER_ONE)
 
@@ -143,6 +144,24 @@ class TestSubmissionsApi(TestCase):
         mock_filter.side_effect = DatabaseError("Bad things happened")
         api.create_submission(STUDENT_ITEM, ANSWER_ONE)
 
+    def test_create_non_json_answer(self):
+        with self.assertRaises(api.SubmissionRequestError):
+            api.create_submission(STUDENT_ITEM, datetime.datetime.now())
+
+    def test_load_non_json_answer(self):
+        # This should never happen, if folks are using the public API.
+        # Create a submission with a raw answer that is NOT valid JSON
+        submission = api.create_submission(STUDENT_ITEM, ANSWER_ONE)
+        sub_model = Submission.objects.get(uuid=submission['uuid'])
+        sub_model.raw_answer = ''
+        sub_model.save()
+
+        with self.assertRaises(api.SubmissionInternalError):
+            api.get_submission(sub_model.uuid)
+
+        with self.assertRaises(api.SubmissionInternalError):
+            api.get_submission_and_student(sub_model.uuid)
+
     @patch.object(StudentItemSerializer, 'save')
     @raises(api.SubmissionInternalError)
     def test_create_student_item_validation(self, mock_save):