Corrected Cache Key Encoding Issues

- Using Unicode when formatting strings that might have Unicode values
- Properly encoding cache keys before hashing to MD5

analytics_dashboard/core/utils.py

@@ -18,4 +18,4 @@ def sanitize_cache_key(key):
     """
     Returns a memcached-safe (no spaces or control characters) key.
     """
-    return md5(key).hexdigest()
+    return md5(key.encode("utf-8")).hexdigest()

analytics_dashboard/courses/presenters/performance.py

@@ -165,7 +165,7 @@ class CoursePerformancePresenter(BasePresenter):
         return answer_distributions
 
     def get_cache_key(self, name):
-        return sanitize_cache_key('{}_{}'.format(self.course_id, name))
+        return sanitize_cache_key(u'{}_{}'.format(self.course_id, name))
 
     @property
     def last_updated(self):
@@ -298,11 +298,11 @@ class CoursePerformancePresenter(BasePresenter):
     def assignments(self, assignment_type=None):
         """ Returns the assignments (and problems) for the represented course. """
 
-        assignment_type_key = self.get_cache_key('assignments_{}'.format(assignment_type))
+        assignment_type_key = self.get_cache_key(u'assignments_{}'.format(assignment_type))
         assignments = cache.get(assignment_type_key)
 
         if not assignments:
-            all_assignments_key = '{}_assignments'.format(self.course_id)
+            all_assignments_key = self.get_cache_key(u'assignments')
             assignments = cache.get(all_assignments_key)
 
             if not assignments:

analytics_dashboard/courses/views/__init__.py

@@ -56,7 +56,7 @@ class CourseAPIMixin(object):
         return super(CourseAPIMixin, self).dispatch(request, *args, **kwargs)
 
     def _course_detail_cache_key(self, course_id):
-        return sanitize_cache_key('course_{}_details'.format(course_id))
+        return sanitize_cache_key(u'course_{}_details'.format(course_id))
 
     def get_course_info(self, course_id):
         """
@@ -83,7 +83,7 @@ class CourseAPIMixin(object):
 
     def get_courses(self):
         # Check the cache for the user's courses
-        key = sanitize_cache_key('user_{}_courses'.format(self.request.user.pk))
+        key = sanitize_cache_key(u'user_{}_courses'.format(self.request.user.pk))
         courses = cache.get(key)
 
         # If no cached courses, iterate over the data from the course API.

analytics_dashboard/courses/views/csv.py

@@ -20,7 +20,7 @@ class CSVResponseMixin(object):
     # pylint: disable=unused-argument
     def render_to_response(self, context, **response_kwargs):
         response = HttpResponse(self.get_data(), content_type='text/csv', **response_kwargs)
-        response['Content-Disposition'] = 'attachment; filename="{0}"'.format(self._get_filename())
+        response['Content-Disposition'] = u'attachment; filename="{0}"'.format(self._get_filename())
         return response
 
     def get_data(self):
@@ -29,7 +29,7 @@ class CSVResponseMixin(object):
     def _get_filename(self):
         course_key = self.course_key
         course_id = '-'.join([course_key.org, course_key.course, course_key.run])
-        filename = '{0}--{1}.csv'.format(course_id, self.csv_filename_suffix)
+        filename = u'{0}--{1}.csv'.format(course_id, self.csv_filename_suffix)
         return urllib.quote(filename)
 
 

analytics_dashboard/courses/views/performance.py

@@ -106,8 +106,8 @@ class PerformanceAnswerDistributionView(PerformanceTemplateView):
         view_live_url = None
 
         if settings.LMS_COURSE_SHORTCUT_BASE_URL:
-            view_live_url = '{0}/{1}/jump_to/{2}'.format(settings.LMS_COURSE_SHORTCUT_BASE_URL, self.course_id,
-                                                         problem_id)
+            view_live_url = u'{0}/{1}/jump_to/{2}'.format(settings.LMS_COURSE_SHORTCUT_BASE_URL, self.course_id,
+                                                          problem_id)
 
         answer_distribution_entry = presenter.get_answer_distribution(problem_id, part_id)