How can I handle InvalidOperationException thrown internally in response to connecting to existing peripheral after toggling Bluetooth off/on?

[vchelaru]

I unfortunately cannot send a demo app because this is part of our commercial product. I am encountering the following callstack when I attempt to re-connect to a peripheral after having connected/subscribed previously. This appears to be all internal Shiny code - it's not called explicitly by my app:

System.InvalidOperationException: No service found with uuid: 0000fff0-0000-1000-8000-00805f9b34fb
  File "Peripheral_Services.cs", line 62, in IObservable<BluetoothGattService> Peripheral.GetNativeService(string serviceUuid)+(IReadOnlyList<BluetoothGattService> x) => { }
    throw new InvalidOperationException("No service found with uuid: " + serviceUuid);
  ?, in void _.OnNext(IReadOnlyList<BluetoothGattService>)
  ?, in void ExceptionServicesImpl.Rethrow(Exception)
  ?, in void ExceptionHelpers.Throw(Exception)
  ?, in void Stubs.Throw(Exception ex)
  ?, in void AnonymousSafeObserver<BleCharacteristicResult>.OnError(Exception)
  ?, in void Sink<BleCharacteristicResult>.ForwardOnError(Exception)
  ?, in void Sink<BleCharacteristicResult, BleCharacteristicResult>.OnError(Exception)
  ?, in void Subject<BleCharacteristicResult>.OnError(Exception)
  ?, in void Sink<BleCharacteristicResult>.ForwardOnError(Exception)
  ?, in void Sink<BleCharacteristicResult, BleCharacteristicResult>.OnError(Exception)
  ?, in void AutoDetachObserver<BleCharacteristicResult>.OnErrorCore(Exception)
  ?, in void ObserverBase<BleCharacteristicResult>.OnError(Exception)
  ?, in void AnonymousSafeObserver<BleCharacteristicResult>.OnError(Exception)
  ?, in void Sink<BleCharacteristicResult>.ForwardOnError(Exception)
  ?, in void _.OnError(Exception)
  ?, in void Sink<IObservable<BleCharacteristicResult>>.ForwardOnError(Exception)
  ?, in void Sink<BluetoothGattCharacteristic, IObservable<BleCharacteristicResult>>.OnError(Exception)
  ?, in void Sink<BluetoothGattCharacteristic>.ForwardOnError(Exception)
  ?, in void _.OnError(Exception)
  ?, in void Sink<IObservable<BluetoothGattCharacteristic>>.ForwardOnError(Exception)
  ?, in void Sink<BluetoothGattCharacteristic, IObservable<BluetoothGattCharacteristic>>.OnError(Exception)
  ?, in void Sink<BluetoothGattCharacteristic>.ForwardOnError(Exception)
  ?, in void InnerObserver.OnError(Exception)
  ?, in void Sink<BluetoothGattCharacteristic>.ForwardOnError(Exception)
  ?, in void Sink<BluetoothGattService, BluetoothGattCharacteristic>.OnError(Exception)
  ?, in void Sink<BluetoothGattService>.ForwardOnError(Exception)
  ?, in void _.OnNext(IReadOnlyList<BluetoothGattService>)
  ?, in void Sink<IReadOnlyList<BluetoothGattService>>.ForwardOnNext(IReadOnlyList<BluetoothGattService>)
  ?, in void IdentitySink<IReadOnlyList<BluetoothGattService>>.OnNext(IReadOnlyList<BluetoothGattService>)
  ?, in void AutoDetachObserver<IReadOnlyList<BluetoothGattService>>.OnNextCore(IReadOnlyList<BluetoothGattService>)
  ?, in void ObserverBase<IReadOnlyList<BluetoothGattService>>.OnNext(IReadOnlyList<BluetoothGattService>)
  ?, in void WrappingSafeObserver.OnNext(IReadOnlyList<BluetoothGattService>)
  ?, in void Sink<IReadOnlyList<BluetoothGattService>>.ForwardOnNext(IReadOnlyList<BluetoothGattService>)
  ?, in void _.Invoke()
  ?, in void <>c.<Run>b__2_0(?)+(_ this) => { }
  ?, in IDisposable <>c__75<_>.<ScheduleAction>b__75_0(?)+(IScheduler _, ValueTuple<Action<_>, _> tuple) => { }
  ?, in IDisposable ImmediateScheduler.Schedule<ValueTuple<Action<_>, _>>(ValueTuple<Action<_>, _>, Func<IScheduler, ValueTuple<Action<_>, _>, IDisposable>)
  ?, in IDisposable Scheduler.ScheduleAction<_>(IScheduler, _, Action<_>)
  ?, in void _.Run(IScheduler)
  ?, in void Return<IReadOnlyList<BluetoothGattService>>.Run(_)
  ?, in IDisposable Producer<IReadOnlyList<BluetoothGattService>, _>.SubscribeRaw(IObserver<IReadOnlyList<BluetoothGattService>>, bool)
  ?, in IDisposable Producer<IReadOnlyList<BluetoothGattService>, _>.Subscribe(IObserver<IReadOnlyList<BluetoothGattService>>)
  ?, in IDisposable StartAsyncObservable<IReadOnlyList<BluetoothGattService>>.SubscribeCore(IObserver<IReadOnlyList<BluetoothGattService>>)
  ?, in IDisposable ObservableBase<IReadOnlyList<BluetoothGattService>>.Subscribe(IObserver<IReadOnlyList<BluetoothGattService>>)
  ?, in IDisposable ObservableExtensions.SubscribeSafe<IReadOnlyList<BluetoothGattService>>(IObservable<IReadOnlyList<BluetoothGattService>>, IObserver<IReadOnlyList<BluetoothGattService>>)
  ?, in void Sink<IReadOnlyList<BluetoothGattService>, IReadOnlyList<BluetoothGattService>>.Run(IObservable<IReadOnlyList<BluetoothGattService>>)
  ?, in void _.Run()
  ?, in void Defer<IReadOnlyList<BluetoothGattService>>.Run(_)
  ?, in IDisposable Producer<IReadOnlyList<BluetoothGattService>, _>.SubscribeRaw(IObserver<IReadOnlyList<BluetoothGattService>>, bool)
  ?, in IDisposable ObservableExtensions.SubscribeSafe<IReadOnlyList<BluetoothGattService>>(IObservable<IReadOnlyList<BluetoothGattService>>, IObserver<IReadOnlyList<BluetoothGattService>>)
  ?, in void Sink<IReadOnlyList<BluetoothGattService>, BluetoothGattService>.Run(IObservable<IReadOnlyList<BluetoothGattService>>)
  ?, in void Selector.Run(_)
  ?, in IDisposable Producer<BluetoothGattService, _>.SubscribeRaw(IObserver<BluetoothGattService>, bool)
  ?, in IDisposable ObservableExtensions.SubscribeSafe<BluetoothGattService>(IObservable<BluetoothGattService>, IObserver<BluetoothGattService>)
  ?, in void Sink<BluetoothGattService, BluetoothGattCharacteristic>.Run(IObservable<BluetoothGattService>)
  ?, in void Selector.Run(_)
  ?, in IDisposable Producer<TTarget, TSink>.SubscribeRaw(IObserver<TTarget>, bool)+(ValueTuple<Producer<BluetoothGattCharacteristic, _>, _> tuple) => { }
  ?, in IDisposable <>c__75<ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>.<ScheduleAction>b__75_0(?)+(IScheduler _, ValueTuple<Action<ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>, ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>> tuple) => { }
  ?, in IDisposable CurrentThreadScheduler.Schedule<ValueTuple<Action<ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>, ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>>(ValueTuple<Action<ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>,...
  ?, in IDisposable LocalScheduler.Schedule<ValueTuple<Action<ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>, ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>>(ValueTuple<Action<ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>, ValueTu...
  ?, in IDisposable Scheduler.ScheduleAction<ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>(IScheduler, ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>, Action<ValueTuple<Producer<BluetoothGattCharacteristic, _>, _>>)
  ?, in IDisposable Producer<BluetoothGattCharacteristic, _>.SubscribeRaw(IObserver<BluetoothGattCharacteristic>, bool)
  ?, in IDisposable ObservableExtensions.SubscribeSafe<BluetoothGattCharacteristic>(IObservable<BluetoothGattCharacteristic>, IObserver<BluetoothGattCharacteristic>)
  ?, in void _.OnNext(IObservable<BluetoothGattCharacteristic>)
  ?, in void Sink<IObservable<BluetoothGattCharacteristic>>.ForwardOnNext(IObservable<BluetoothGattCharacteristic>)
  ?, in void _.OnNext(IPeripheral)
  ?, in void Sink<IPeripheral>.ForwardOnNext(IPeripheral)
  ?, in void _.OnNext(ConnectionState)
  ?, in void Sink<ConnectionState>.ForwardOnNext(ConnectionState)
  ?, in void _.OnNext(ConnectionState)
  ?, in void Sink<ConnectionState>.ForwardOnNext(ConnectionState)
  ?, in void IdentitySink<ConnectionState>.OnNext(ConnectionState)
  ?, in void Subject<ConnectionState>.OnNext(ConnectionState)
  File "Peripheral.cs", line 159, in void Peripheral.OnConnectionStateChange(BluetoothGatt gatt, GattStatus status, ProfileState newState)
    this.connSubj.OnNext(newState.ToStatus());
  ?, in void BluetoothGattCallback.n_OnConnectionStateChange_Landroid_bluetooth_BluetoothGatt_II(IntPtr jnienv, IntPtr native__this, IntPtr native_gatt, int native_status, int native_newState)
  ?, in void JNINativeWrapper.Wrap_JniMarshal_PPLII_V(_JniMarshal_PPLII_V callback, IntPtr jnienv, IntPtr klazz, IntPtr p0, int p1, int p2)

I believe the repro steps are:

1. Scan for a peripheral
2. Connect to the peripheral
3. Subscribe to a characteristic which can notify
4. Verify the characteristic is subscribed
5. Turn off BLE on the Android operating system
6. Return to the app to verify the peripheral is no longer connected
7. Turn bluetooth back on at the operating system level
8. Call Connect on the perhipheral
9. Wait...

The exception is thrown. I expect I should be able to (and should be required to) re-connect to the device after having turned off bluetooth, and I'm not sure why I'm getting this exception.

Update 1

If I connect without subscribing, the error does not occur. This is to be expected because the error indicates a particular service UUID which could only be obtained through the subscribe call.

If I subscribe with the following code...

Peripheral.NotifyCharacteristic(WriteServiceUuid, NotificationCharacteristicUuid)
    .Subscribe(HandleNotificationSubscription);

...then the connection attempt after toggling OS-level bluetooth off/on seems to fail. Does this mean I must somehow unsubscribe from the characteristic? Or should I not be doing a connect explicitly after I've successfully notified?

Any help would be appreciated, thanks in advance.

[aritchie]

Subscribe has an overload to trap errors. Please read on reactive extensions in order to use RX properly

[vchelaru]

For future readers:

Peripheral.NotifyCharacteristic(WriteServiceUuid, NotificationCharacteristicUuid)
   .Subscribe(HandleNotificationSubscription, HandleException);

// ...
private void HandleException(Exception exception)
{
    // do we care to do anything here? I think we just tolerate it...
}