WIP: winrt/client: implement pairing callbacks

This is a work in progress and breaks stdin pairing_agent.py causing ^C
to not work. Also, the pair() method will hang forever if the pairing
is rejected or an invalid value is returned from a pairing callback.

Author: dlech

bleak/backends/winrt/client.py

@@ -43,13 +43,21 @@
     DevicePairingKinds,
     DevicePairingResultStatus,
     DeviceUnpairingResultStatus,
+    DevicePairingRequestedEventArgs,
+    DeviceInformationCustomPairing,
 )
 from bleak_winrt.windows.foundation import EventRegistrationToken
 from bleak_winrt.windows.storage.streams import Buffer
 
 from ... import BleakScanner
 from ...agent import BaseBleakAgentCallbacks
-from ...exc import PROTOCOL_ERROR_CODES, BleakDeviceNotFoundError, BleakError
+from ...exc import (
+    PROTOCOL_ERROR_CODES,
+    BleakDeviceNotFoundError,
+    BleakError,
+    BleakPairingCancelledError,
+    BleakPairingFailedError,
+)
 from ..characteristic import BleakGATTCharacteristic
 from ..client import BaseBleakClient, NotifyCallback
 from ..device import BLEDevice
@@ -251,7 +259,7 @@ async def connect(self, **kwargs) -> bool:
 
         def handle_services_changed():
             if not self._services_changed_events:
-                logger.warn("%s: unhandled services changed event", self.address)
+                logger.warning("%s: unhandled services changed event", self.address)
             else:
                 for event in self._services_changed_events:
                     event.set()
@@ -446,52 +454,91 @@ async def pair(
         """
         Attempts to pair with the device.
         """
-        if callbacks:
-            raise NotImplementedError
-
         # New local device information object created since the object from the requester isn't updated
-        device_information = await DeviceInformation.create_from_id_async(
-            self._requester.device_information.id
+        device_information: DeviceInformation = (
+            await DeviceInformation.create_from_id_async(
+                self._requester.device_information.id
+            )
         )
-        if (
-            device_information.pairing.can_pair
-            and not device_information.pairing.is_paired
-        ):
 
-            # Currently only supporting Just Works solutions...
-            ceremony = DevicePairingKinds.CONFIRM_ONLY
-            custom_pairing = device_information.pairing.custom
+        if device_information.pairing.is_paired:
+            logger.debug("already paired")
+            return True
 
-            def handler(sender, args):
-                args.accept()
+        if not device_information.pairing.can_pair:
+            raise BleakError("device does not support pairing")
 
-            pairing_requested_token = custom_pairing.add_pairing_requested(handler)
-            try:
-                if protection_level:
-                    pairing_result = await custom_pairing.pair_async(
-                        ceremony, protection_level
-                    )
-                else:
-                    pairing_result = await custom_pairing.pair_async(ceremony)
+        if callbacks:
 
-            except Exception as e:
-                raise BleakError("Failure trying to pair with device!") from e
-            finally:
-                custom_pairing.remove_pairing_requested(pairing_requested_token)
+            loop = asyncio.get_running_loop()
 
-            if pairing_result.status not in (
-                DevicePairingResultStatus.PAIRED,
-                DevicePairingResultStatus.ALREADY_PAIRED,
+            def handle_pairing_requested(
+                sender: DeviceInformationCustomPairing,
+                args: DevicePairingRequestedEventArgs,
             ):
-                raise BleakError(f"Could not pair with device: {pairing_result.status}")
-            else:
-                logger.info(
-                    "Paired to device with protection level %d.",
-                    pairing_result.protection_level_used,
+                print(args.pairing_kind, args.pin)
+                logger.debug("kind: %r, pin: %s", args.pairing_kind, args.pin)
+
+                deferral = args.get_deferral()
+
+                async def handle_callback():
+                    print("prompt")
+                    try:
+                        ble_device = BLEDevice(
+                            args.device_information.id,
+                            args.device_information.name,
+                            args.device_information,
+                        )
+
+                        if args.pairing_kind & DevicePairingKinds.CONFIRM_PIN_MATCH:
+                            if await callbacks.confirm_pin(ble_device):
+                                args.accept()
+                        elif args.pairing_kind & DevicePairingKinds.PROVIDE_PIN:
+                            pin = await callbacks.request_pin(ble_device)
+
+                            if pin:
+                                args.accept(pin)
+                        elif args.pairing_kind & DevicePairingKinds.DISPLAY_PIN:
+                            await callbacks.display_pin(ble_device, args.pin)
+                            args.accept()
+                        elif args.pairing_kind & DevicePairingKinds.CONFIRM_ONLY:
+                            if await callbacks.confirm(ble_device):
+                                args.accept()
+                    finally:
+                        print("complete")
+                        deferral.complete()
+
+                loop.call_soon_threadsafe(loop.create_task, handle_callback())
+
+            token = device_information.pairing.custom.add_pairing_requested(
+                handle_pairing_requested
+            )
+            try:
+                result = await device_information.pairing.custom.pair_async(
+                    DevicePairingKinds.CONFIRM_ONLY
+                    | DevicePairingKinds.DISPLAY_PIN
+                    | DevicePairingKinds.PROVIDE_PIN
+                    | DevicePairingKinds.CONFIRM_PIN_MATCH
                 )
-                return True
+            finally:
+                device_information.pairing.custom.remove_pairing_requested(token)
+
         else:
-            return device_information.pairing.is_paired
+            result = await device_information.pairing.pair_async()
+
+        if result.status == DevicePairingResultStatus.PAIRING_CANCELED:
+            raise BleakPairingCancelledError
+
+        if result.status == DevicePairingResultStatus.FAILED:
+            raise BleakPairingFailedError
+
+        if result.status not in [
+            DevicePairingResultStatus.PAIRED,
+            DevicePairingResultStatus.ALREADY_PAIRED,
+        ]:
+            raise BleakError("pairing failed", result.status)
+
+        return True
 
     async def unpair(self) -> bool:
         """Attempts to unpair from the device.

examples/pairing_agent.py

@@ -1,34 +1,44 @@
 import argparse
 import asyncio
+from concurrent.futures import Future
 import sys
+import threading
 
 from bleak import BleakScanner, BleakClient, BaseBleakAgentCallbacks
 from bleak.backends.device import BLEDevice
-from bleak.exc import BleakPairingCancelledError, BleakPairingFailedError
+from bleak.exc import (
+    BleakDeviceNotFoundError,
+    BleakPairingCancelledError,
+    BleakPairingFailedError,
+)
 
 
-class AgentCallbacks(BaseBleakAgentCallbacks):
-    def __init__(self) -> None:
-        super().__init__()
-        self._reader = asyncio.StreamReader()
+async def run_as_daemon(func, *args):
+    future = Future()
+    future.set_running_or_notify_cancel()
+
+    def daemon():
+        try:
+            result = func(*args)
+            print("result", result)
+        except BaseException as e:
+            future.set_exception(e)
+        else:
+            future.set_result(result)
 
-    async def __aenter__(self):
-        loop = asyncio.get_running_loop()
-        protocol = asyncio.StreamReaderProtocol(self._reader)
-        self._input_transport, _ = await loop.connect_read_pipe(
-            lambda: protocol, sys.stdin
-        )
-        return self
+    threading.Thread(target=daemon, daemon=True).start()
+    return await asyncio.wrap_future(future)
 
-    async def __aexit__(self, *args):
-        self._input_transport.close()
 
+class AgentCallbacks(BaseBleakAgentCallbacks):
     async def _input(self, msg: str) -> str:
         """
         Async version of the builtin input function.
         """
         print(msg, end=" ", flush=True)
-        return (await self._reader.readline()).decode().strip()
+        line: str = await run_as_daemon(sys.stdin.readline)
+        print("line", line)
+        return line.strip()
 
     async def confirm(self, device: BLEDevice) -> bool:
         print(f"{device.name} wants to pair.")
@@ -52,13 +62,18 @@ async def request_pin(self, device: BLEDevice) -> str:
         print(f"{device.name} wants to pair.")
         response = await self._input("enter pin:")
 
+        print("response", response)
+
         return response
 
 
 async def main(addr: str, unpair: bool) -> None:
     if unpair:
         print("unpairing...")
-        await BleakClient(addr).unpair()
+        try:
+            await BleakClient(addr).unpair()
+        except BleakDeviceNotFoundError:
+            pass
 
     print("scanning...")
 
@@ -68,9 +83,12 @@ async def main(addr: str, unpair: bool) -> None:
         print("device was not found")
         return
 
-    async with BleakClient(device) as client, AgentCallbacks() as callbacks:
+    print("pairing...")
+    callbacks = AgentCallbacks()
+    async with BleakClient(device) as client:
         try:
             await client.pair(callbacks)
+            print("success")
         except BleakPairingCancelledError:
             print("paring was canceled")
         except BleakPairingFailedError: