Upload sync filter & use filter ID for syncs

rather than passing an entire filter dict for every single syncs.
This shortens the request URL and prevents troubles with some servers
that have an absurdly low max URL length (e.g. halogen.city).

src/backend/matrix_client.py

@@ -75,6 +75,12 @@ REPLY_FALLBACK = (
 )
 
 
+class SyncFilterIds(NamedTuple):
+    """Uploaded filter IDs for various API."""
+
+    first:  str
+    others: str
+
 class UploadReturn(NamedTuple):
     """Details for an uploaded file."""
 
@@ -185,10 +191,12 @@ class MatrixClient(nio.AsyncClient):
         self.upload_tasks:       Dict[UUID, asyncio.Task]        = {}
         self.send_message_tasks: Dict[UUID, asyncio.Task]        = {}
 
-        self._presence:       str                 = ""
+        self._presence:             str                     = ""
-        self.first_sync_done: asyncio.Event       = asyncio.Event()
+        self._sync_filter_ids:      Optional[SyncFilterIds] = None
-        self.first_sync_date: Optional[datetime]  = None
+        self._sync_filter_ids_lock: asyncio.Lock            = asyncio.Lock()
-        self.last_sync_error: Optional[Exception] = None
+        self.first_sync_done:       asyncio.Event           = asyncio.Event()
+        self.first_sync_date:       Optional[datetime]      = None
+        self.last_sync_error:       Optional[Exception]     = None
 
         self.past_tokens:          Dict[str, str] = {}     # {room_id: token}
         self.fully_loaded_rooms:   Set[str]       = set()  # {room_id}
@@ -370,25 +378,17 @@ class MatrixClient(nio.AsyncClient):
         )
         self.server_config_task.add_done_callback(on_server_config_response)
 
-        filter1 = deepcopy(self.lazy_load_filter)
-        utils.dict_update_recursive(filter1, self.low_limit_filter)
-
-        cfg = self.backend.ui_settings
-
-        if cfg["hideUnknownEvents"]:
-            filter1["room"]["timeline"]["not_types"].extend(
-                self.no_unknown_events_filter["room"]["timeline"]["not_types"],
-            )
-
         await self.auto_verify_all_other_accounts()
 
         while True:
             try:
+                sync_filter_ids = await self.sync_filter_ids()
+
                 self.sync_task = asyncio.ensure_future(self.sync_forever(
                     timeout           = 10_000,
                     loop_sleep_time   = 1000,
-                    sync_filter       = self.lazy_load_filter,
+                    first_sync_filter = sync_filter_ids.first,
-                    first_sync_filter = filter1,
+                    sync_filter       = sync_filter_ids.others,
                 ))
                 await self.sync_task
                 break  # task cancelled
@@ -454,6 +454,35 @@ class MatrixClient(nio.AsyncClient):
         return (await self.content_repository_config()).upload_size
 
 
+    async def sync_filter_ids(self) -> SyncFilterIds:
+        """Return our sync/messages filter IDs, upload them if needed."""
+
+        async with self._sync_filter_ids_lock:
+            if self._sync_filter_ids:
+                return self._sync_filter_ids
+
+            others = deepcopy(self.lazy_load_filter)
+            first  = deepcopy(others)
+
+            utils.dict_update_recursive(first, self.low_limit_filter)
+
+            if self.backend.ui_settings["hideUnknownEvents"]:
+                first["room"]["timeline"]["not_types"].extend(
+                    self.no_unknown_events_filter
+                    ["room"]["timeline"]["not_types"],
+                )
+
+            others_id = (await self.upload_filter(**others)).filter_id
+            first_id  = others_id
+
+            if others != first:
+                resp     = await self.upload_filter(**first)
+                first_id = resp.filter_id
+
+            self._sync_filter_ids = SyncFilterIds(others_id, first_id)
+            return self._sync_filter_ids
+
+
     async def pause_while_offline(self) -> None:
         """Block until our account is online."""
         while (