Add questionnaire reset functionality

Author: reppuli92

exercise/cache/exercise.py

@@ -44,6 +44,10 @@ def __init__( # pylint: disable=too-many-arguments
         super().__init__(exercise, modifiers=[language])
 
     def _needs_generation(self, data: Dict[str, Any]) -> bool:
+        if data and 'exercise_version' not in data:
+            # Cache entries created before exercise version stamping was added
+            # must be refreshed so update detection can work.
+            return True
         expires = data['expires'] if data else None
         return not expires or time.time() > expires
     # pylint: disable-next=arguments-differ
@@ -60,6 +64,7 @@ def _generate_data(self, exercise: 'BaseExercise', data: Optional[Dict[str, Any]
                 'head': page.head,
                 'content': content,
                 'last_modified': page.last_modified,
+                'exercise_version': page.exercise_version,
                 'expires': page.expires if page.is_loaded else 0,
             }
         except RemotePageNotModified as e:
@@ -74,6 +79,9 @@ def content(self) -> str:
         content = decompress(self.data['content']).decode('utf-8')
         return content
 
+    def exercise_version(self) -> str:
+        return self.data.get('exercise_version') or ''
+
 
 def invalidate_instance(instance: 'CourseInstance') -> None:
     for module in instance.course_modules.all():

exercise/protocol/aplus.py

@@ -181,4 +181,5 @@ def parse_page_content(
     id_attrs_to_remove = ('exercise', 'chapter', 'aplus')
     page.content, page.clean_content = remote_page.element_or_body(element_selectors, id_attrs_to_remove)
     page.last_modified = remote_page.last_modified()
+    page.exercise_version = remote_page.meta("x-aplus-exercise-version") or ""
     page.expires = remote_page.expires()

exercise/protocol/exercise_page.py

@@ -23,6 +23,7 @@ def __init__(self, exercise):
         self.content = ""
         self.clean_content = ""
         self.last_modified = ""
+        self.exercise_version = ""  # content hash supplied by mooc-grader
         self.expires = 0
         self.meta = {
             "title": exercise.name,

exercise/submission_models.py

@@ -31,6 +31,7 @@
 from lti_tool.utils import has_lti_access_to_course
 from userprofile.models import UserProfile
 from aplus.celery import retry_submissions
+from .cache.exercise import ExerciseCache
 from . import exercise_models
 from .exercise_models import LearningObjectProto
 
@@ -255,6 +256,20 @@ def create_from_post(self, exercise, submitters, request):
         if 'lang' not in meta_data_dict:
             meta_data_dict['lang'] = get_language()
 
+        # Store the current exercise page version for later compatibility checks
+        # when deciding whether old feedback can be shown.
+
+        exercise_cache = ExerciseCache(
+            exercise,
+            meta_data_dict['lang'],
+            request,
+            submitters,
+            'exercise',
+        )
+        version = exercise_cache.exercise_version()
+        if version:
+            meta_data_dict['exercise_version'] = version
+
         try:
             if ('lti-launch-id' in request.session
                     and has_lti_access_to_course(request, None, exercise.course_instance)):

exercise/views.py

@@ -25,6 +25,7 @@
 from lib.remote_page import RemotePageNotFound, request_for_response
 from lib.viewbase import BaseFormView, BaseRedirectMixin, BaseView
 from userprofile.models import UserProfile
+from .cache.exercise import ExerciseCache
 from .cache.points import CachedPoints, ModulePoints, ExercisePoints
 from .models import BaseExercise, LearningObject, LearningObjectDisplay
 from .protocol.exercise_page import ExercisePage
@@ -296,6 +297,16 @@ def submission_check(self, request=None):
         )
         return submission_status, submission_allowed, issues, students
 
+    def _get_current_exercise_version(self, request: HttpRequest, students: List[UserProfile]) -> Optional[str]:
+        cache = ExerciseCache(
+            self.exercise,
+            get_language(),
+            request,
+            students,
+            self.post_url_name,
+        )
+        return cache.exercise_version() or None
+
     def get_page(self, request: HttpRequest, students: List[UserProfile]) -> ExercisePage:
         """
         Determines which page should be displayed for this exercise:
@@ -338,6 +349,21 @@ def get_page(self, request: HttpRequest, students: List[UserProfile]) -> Exercis
                             url_name=self.post_url_name,
                         )
                     if self.feedback_revealed:
+                        submission_version = (submission.meta_data or {}).get('exercise_version')
+                        submission_language = submission.lang
+                        current_language = get_language()
+                        current_version = self._get_current_exercise_version(request, students)
+                        if (
+                            (submission_language is not None
+                                and submission_language != current_language)
+                            or (current_version is not None
+                                and submission_version != current_version)
+                        ):
+                            return self.exercise.load(
+                                request,
+                                students,
+                                url_name=self.post_url_name,
+                            )
                         page = ExercisePage(self.exercise)
                         page.content = submission.feedback
                         page.is_loaded = True