Add a config option to change whether unread push notification counts are per-message or per-room (#8820)

This PR adds a new config option to the `push` section of the homeserver config, `group_unread_count_by_room`. By default Synapse will group push notifications by room (so if you have 1000 unread messages, if they lie in 55 rooms, you'll see an unread count on your phone of 55).

However, it is also useful to be able to send out the true count of unread messages if desired. If `group_unread_count_by_room` is set to `false`, then with the above example, one would see an unread count of 1000 (email anyone?).

3 files changed, 35 insertions, 7 deletions

diff --git a/synapse/config/push.py b/synapse/config/push.py
index a71baac89c..3adbfb73e6 100644
--- a/synapse/config/push.py
+++ b/synapse/config/push.py
@@ -23,6 +23,9 @@ class PushConfig(Config):
     def read_config(self, config, **kwargs):
         push_config = config.get("push") or {}
         self.push_include_content = push_config.get("include_content", True)
+        self.push_group_unread_count_by_room = push_config.get(
+            "group_unread_count_by_room", True
+        )
 
         pusher_instances = config.get("pusher_instances") or []
         self.pusher_shard_config = ShardedWorkerHandlingConfig(pusher_instances)
@@ -68,4 +71,14 @@ class PushConfig(Config):
           # include the event ID and room ID in push notification payloads.
           #
           #include_content: false
+
+          # When a push notification is received, an unread count is also sent.
+          # This number can either be calculated as the number of unread messages
+          # for the user, or the number of *rooms* the user has unread messages in.
+          #
+          # The default value is "true", meaning push clients will see the number of
+          # rooms with unread messages in them. Uncomment to instead send the number
+          # of unread messages.
+          #
+          #group_unread_count_by_room: false
         """
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index 793d0db2d9..eff0975b6a 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -75,6 +75,7 @@ class HttpPusher:
         self.failing_since = pusherdict["failing_since"]
         self.timed_call = None
         self._is_processing = False
+        self._group_unread_count_by_room = hs.config.push_group_unread_count_by_room
 
         # This is the highest stream ordering we know it's safe to process.
         # When new events arrive, we'll be given a window of new events: we
@@ -136,7 +137,11 @@ class HttpPusher:
     async def _update_badge(self):
         # XXX as per https://github.com/matrix-org/matrix-doc/issues/2627, this seems
         # to be largely redundant. perhaps we can remove it.
-        badge = await push_tools.get_badge_count(self.hs.get_datastore(), self.user_id)
+        badge = await push_tools.get_badge_count(
+            self.hs.get_datastore(),
+            self.user_id,
+            group_by_room=self._group_unread_count_by_room,
+        )
         await self._send_badge(badge)
 
     def on_timer(self):
@@ -283,7 +288,11 @@ class HttpPusher:
             return True
 
         tweaks = push_rule_evaluator.tweaks_for_actions(push_action["actions"])
-        badge = await push_tools.get_badge_count(self.hs.get_datastore(), self.user_id)
+        badge = await push_tools.get_badge_count(
+            self.hs.get_datastore(),
+            self.user_id,
+            group_by_room=self._group_unread_count_by_room,
+        )
 
         event = await self.store.get_event(push_action["event_id"], allow_none=True)
         if event is None:
diff --git a/synapse/push/push_tools.py b/synapse/push/push_tools.py
index d0145666bf..6e7c880dc0 100644
--- a/synapse/push/push_tools.py
+++ b/synapse/push/push_tools.py
@@ -12,12 +12,12 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 from synapse.push.presentable_names import calculate_room_name, name_from_member_event
 from synapse.storage import Storage
+from synapse.storage.databases.main import DataStore
 
 
-async def get_badge_count(store, user_id):
+async def get_badge_count(store: DataStore, user_id: str, group_by_room: bool) -> int:
     invites = await store.get_invited_rooms_for_local_user(user_id)
     joins = await store.get_rooms_for_user(user_id)
 
@@ -34,9 +34,15 @@ async def get_badge_count(store, user_id):
                     room_id, user_id, last_unread_event_id
                 )
             )
-            # return one badge count per conversation, as count per
-            # message is so noisy as to be almost useless
-            badge += 1 if notifs["notify_count"] else 0
+            if notifs["notify_count"] == 0:
+                continue
+
+            if group_by_room:
+                # return one badge count per conversation
+                badge += 1
+            else:
+                # increment the badge count by the number of unread messages in the room
+                badge += notifs["notify_count"]
     return badge