Don't show peer grading button unless there is a peer grading element in the course

lms/djangoapps/open_ended_grading/views.py

@@ -89,21 +89,15 @@ def staff_grading(request, course_id):
         # Checked above
         'staff_access': True, })
 
+def find_peer_grading_module(course):
+    #Reverse the base course url
+    base_course_url = reverse('courses')
+    found_module = False
+    problem_url = ""
 
-@cache_control(no_cache=True, no_store=True, must_revalidate=True)
-def peer_grading(request, course_id):
-    '''
-    Show a peer grading interface
-    '''
-
-    #Get the current course
-    course = get_course_with_access(request.user, course_id, 'load')
+    #Get the course id and split it
     course_id_parts = course.id.split("/")
     false_dict = [False, "False", "false", "FALSE"]
-
-    #Reverse the base course url
-    base_course_url = reverse('courses')
-    try:
     #TODO:  This will not work with multiple runs of a course.  Make it work.  The last key in the Location passed
     #to get_items is called revision.  Is this the same as run?
     #Get the peer grading modules currently in the course
@@ -111,19 +105,33 @@ def peer_grading(request, course_id):
     #See if any of the modules are centralized modules (ie display info from multiple problems)
     items = [i for i in items if getattr(i,"use_for_single_location", True) in false_dict]
     #Get the first one
+    if len(items)>0:
         item_location = items[0].location
         #Generate a url for the first module and redirect the user to it
         problem_url_parts = search.path_to_location(modulestore(), course.id, item_location)
         problem_url = generate_problem_url(problem_url_parts, base_course_url)
+        found_module = True
 
-        return HttpResponseRedirect(problem_url)
-    except:
+    return found_module, problem_url
+
+@cache_control(no_cache=True, no_store=True, must_revalidate=True)
+def peer_grading(request, course_id):
+    '''
+    Show a peer grading interface
+    '''
+
+    #Get the current course
+    course = get_course_with_access(request.user, course_id, 'load')
+
+    found_module, problem_url = find_peer_grading_module(course)
+    if not found_module:
         #This is a student_facing_error
         error_message = "Error with initializing peer grading.  Centralized module does not exist.  Please contact course staff."
         #This is a dev_facing_error
         log.exception(error_message + "Current course is: {0}".format(course_id))
         return HttpResponse(error_message)
 
+    return HttpResponseRedirect(problem_url)
 
 def generate_problem_url(problem_url_parts, base_course_url):
     """
@@ -300,6 +308,11 @@ def combined_notifications(request, course_id):
                 'description': description,
                 'alert_message': alert_message
             }
+            if human_name == "Peer Grading":
+                found_module, problem_url = find_peer_grading_module(course)
+                if found_module:
+                    notification_list.append(notification_item)
+            else:
                 notification_list.append(notification_item)
 
     ajax_url = _reverse_with_slash('open_ended_notifications', course_id)