update read_marker so receipts aren't sent to large rooms

Author: incognitobeeper

synapse/rest/client/read_marker.py

@@ -15,7 +15,7 @@
 import logging
 from typing import TYPE_CHECKING, Tuple
 
-from synapse.api.constants import ReceiptTypes
+from synapse.api.constants import RECEIPTS_MAX_ROOM_SIZE, ReceiptTypes
 from synapse.http.server import HttpServer
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.http.site import SynapseRequest
@@ -38,6 +38,7 @@ def __init__(self, hs: "HomeServer"):
         self.config = hs.config
         self.receipts_handler = hs.get_receipts_handler()
         self.read_marker_handler = hs.get_read_marker_handler()
+        self.store = hs.get_datastores().main
         self.presence_handler = hs.get_presence_handler()
 
         self._known_receipt_types = {
@@ -55,6 +56,14 @@ async def on_POST(
 
         body = parse_json_object_from_request(request)
 
+        # Beeper: we don't want to send read receipts to large rooms,
+        # so we convert messages to private, that are over RECEIPT_MAX_ROOM_SIZE.
+        if ReceiptTypes.READ in body:
+            num_users = await self.store.get_number_joined_users_in_room(room_id)
+            if num_users > RECEIPTS_MAX_ROOM_SIZE:
+                body[ReceiptTypes.READ_PRIVATE] = body[ReceiptTypes.READ]
+                del body[ReceiptTypes.READ]
+
         unrecognized_types = set(body.keys()) - self._known_receipt_types
         if unrecognized_types:
             # It's fine if there are unrecognized receipt types, but let's log

tests/rest/client/test_sync.py

@@ -530,6 +530,53 @@ def test_read_receipt_not_sent_to_large_rooms(self) -> None:
             # Test that we didn't get a read receipt.
             self.assertIsNone(self._get_read_receipt())
 
+    def test_read_marker_doesnt_send_receipt_to_large_rooms(self) -> None:
+        # Beeper: we don't send read receipts on rooms with over 100 users
+        # add another 100 users to the room
+        for i in range(RECEIPTS_MAX_ROOM_SIZE):
+            user = self.register_user(f"user_{i}", f"secure_password_{i}")
+            tok = self.login(f"user_{i}", f"secure_password_{i}")
+            self.helper.join(room=self.room_id, user=user, tok=tok)
+
+        res = self.helper.send(
+            self.room_id, body="woah, this is a big room!", tok=self.tok
+        )
+
+        # Send a read receipt
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/read_markers",
+            {
+                ReceiptTypes.FULLY_READ: res["event_id"],
+                ReceiptTypes.READ: res["event_id"],
+            },
+            access_token=self.tok2,
+        )
+
+        self.assertEqual(channel.code, 200, channel.json_body)
+        # Test that we didn't get a read receipt.
+        self.assertIsNone(self._get_read_receipt())
+
+    def test_read_marker_does_send_receipt_to_small_rooms(self) -> None:
+        res = self.helper.send(
+            self.room_id, body="woah, this is room is tiny!", tok=self.tok
+        )
+
+        # Send a read receipt
+        channel = self.make_request(
+            "POST",
+            f"/rooms/{self.room_id}/read_markers",
+            {
+                ReceiptTypes.FULLY_READ: res["event_id"],
+                ReceiptTypes.READ: res["event_id"],
+            },
+            access_token=self.tok2,
+        )
+
+        self.assertEqual(channel.code, 200, channel.json_body)
+        # Test that we didn't get a read receipt.
+        self.assertIsNotNone(self._get_read_receipt())
+
     def _get_read_receipt(self) -> Optional[JsonDict]:
         """Syncs and returns the read receipt."""