backends/scanner: always filter by service_uuids

CHANGELOG.rst

@@ -34,6 +34,7 @@ Fixed
 * Fixed using wrong value for ``tx_power`` in Android backend. Fixes #1532.
 * Fixed 4-character UUIDs not working on ``BleakClient.*_gatt_char`` methods. Fixes #1498.
 * Fixed race condition with getting max PDU size on Windows. Fixes #1497.
+* Fixed filtering advertisement data by service UUID when multiple apps are scanning. Fixes #1534.
 
 `0.21.1`_ (2023-09-08)
 ======================

bleak/backends/scanner.py

@@ -206,6 +206,24 @@ def call_detection_callbacks(
         Backend implementations should call this method when an advertisement
         event is received from the OS.
         """
+
+        # Backends will make best effort to filter out advertisements that
+        # don't match the service UUIDs, but if other apps are scanning at the
+        # same time or something like that, we may still receive advertisements
+        # that don't match. So we need to do more filtering here to get the
+        # expected behavior.
+
+        if self._service_uuids:
+            if not advertisement_data.service_uuids:
+                return
+
+            for uuid in advertisement_data.service_uuids:
+                if uuid in self._service_uuids:
+                    break
+            else:
+                # if there were no matching service uuids, the don't call the callback
+                return
+
         for callback in self._ad_callbacks.values():
             callback(device, advertisement_data)
 

bleak/backends/winrt/scanner.py

@@ -96,6 +96,11 @@ def __init__(
         else:
             self._scanning_mode = BluetoothLEScanningMode.ACTIVE
 
+        # Unfortunately, due to the way Windows handles filtering, we can't
+        # make use of the service_uuids filter here. If we did we would only
+        # get the advertisement data or the scan data, but not both, so would
+        # miss out on other essential data. Advanced users can pass their own
+        # filters though if they want to.
         self._signal_strength_filter = kwargs.get("SignalStrengthFilter", None)
         self._advertisement_filter = kwargs.get("AdvertisementFilter", None)
 
@@ -198,20 +203,6 @@ def _received_handler(
             bdaddr, local_name, raw_data, advertisement_data
         )
 
-        # On Windows, we have to fake service UUID filtering. If we were to pass
-        # a BluetoothLEAdvertisementFilter to the BluetoothLEAdvertisementWatcher
-        # with the service UUIDs appropriately set, we would no longer receive
-        # scan response data (which commonly contains the local device name).
-        # So we have to do it like this instead.
-
-        if self._service_uuids:
-            for uuid in uuids:
-                if uuid in self._service_uuids:
-                    break
-            else:
-                # if there were no matching service uuids, the don't call the callback
-                return
-
         self.call_detection_callbacks(device, advertisement_data)
 
     def _stopped_handler(self, sender, e):