MA-668 Mobile Push Notification payload update

Support iOS receiving the update even when in the background.
Support Android detecting duplicates.

cms/djangoapps/contentstore/push_notification.py

@@ -2,6 +2,7 @@
 Helper methods for push notifications from Studio.
 """
 
+from uuid import uuid4
 from django.conf import settings
 from logging import exception as log_exception
 
@@ -46,17 +47,36 @@ def send_push_course_update(course_key_string, course_subscription_id, course_di
                 settings.PARSE_KEYS["APPLICATION_ID"],
                 settings.PARSE_KEYS["REST_API_KEY"],
             )
+            push_payload = {
+                "action": "course.announcement",
+                "notification-id": unicode(uuid4()),
+
+                "course-id": course_key_string,
+                "course-name": course_display_name,
+            }
+            push_channels = [course_subscription_id]
+
+            # Push to all Android devices
+            Push.alert(
+                data=push_payload,
+                channels={"$in": push_channels},
+                where={"deviceType": "android"},
+            )
+
+            # Push to all iOS devices
+            # With additional payload so that
+            # 1. The push is displayed automatically
+            # 2. The app gets it even in the background.
+            # See http://stackoverflow.com/questions/19239737/silent-push-notification-in-ios-7-does-not-work
+            push_payload.update({
+                "alert": "",
+                "content-available": 1
+            })
             Push.alert(
-                data={
-                    "course-id": course_key_string,
-                    "action": "course.announcement",
-                    "action-loc-key": "VIEW_BUTTON",
-                    "loc-key": "COURSE_ANNOUNCEMENT_NOTIFICATION_BODY",
-                    "loc-args": [course_display_name],
-                    "title-loc-key": "COURSE_ANNOUNCEMENT_NOTIFICATION_TITLE",
-                    "title-loc-args": [],
-                },
-                channels=[course_subscription_id],
+                data=push_payload,
+                channels={"$in": push_channels},
+                where={"deviceType": "ios"},
             )
+
         except ParseError as error:
             log_exception(error.message)

cms/djangoapps/contentstore/views/tests/test_course_updates.py

@@ -303,4 +303,14 @@ class CourseUpdateTest(CourseTestCase):
     def test_notifications_sent_to_parse(self, mock_parse_push):
         PushNotificationConfig(enabled=True).save()
         self.post_course_update(send_push_notification=True)
-        self.assertTrue(mock_parse_push.alert.called)
+        self.assertEquals(mock_parse_push.alert.call_count, 2)
+
+    @override_settings(PARSE_KEYS={"APPLICATION_ID": "TEST_APPLICATION_ID", "REST_API_KEY": "TEST_REST_API_KEY"})
+    @patch("contentstore.push_notification.log_exception")
+    @patch("contentstore.push_notification.Push")
+    def test_notifications_error_from_parse(self, mock_parse_push, mock_log_exception):
+        PushNotificationConfig(enabled=True).save()
+        from parse_rest.core import ParseError
+        mock_parse_push.alert.side_effect = ParseError
+        self.post_course_update(send_push_notification=True)
+        self.assertTrue(mock_log_exception.called)