335 lines
9.7 KiB
Python
335 lines
9.7 KiB
Python
import abc
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import asyncio
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import inspect
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import os
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import platform
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from typing import (
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Any,
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Callable,
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Coroutine,
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Dict,
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Hashable,
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List,
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NamedTuple,
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Optional,
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Set,
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Tuple,
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Type,
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)
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from ..exc import BleakError
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from .device import BLEDevice
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# prevent tasks from being garbage collected
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_background_tasks: Set[asyncio.Task] = set()
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class AdvertisementData(NamedTuple):
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"""
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Wrapper around the advertisement data that each platform returns upon discovery
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"""
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local_name: Optional[str]
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"""
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The local name of the device or ``None`` if not included in advertising data.
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"""
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manufacturer_data: Dict[int, bytes]
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"""
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Dictionary of manufacturer data in bytes from the received advertisement data or empty dict if not present.
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The keys are Bluetooth SIG assigned Company Identifiers and the values are bytes.
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https://www.bluetooth.com/specifications/assigned-numbers/company-identifiers/
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"""
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service_data: Dict[str, bytes]
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"""
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Dictionary of service data from the received advertisement data or empty dict if not present.
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"""
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service_uuids: List[str]
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"""
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List of service UUIDs from the received advertisement data or empty list if not present.
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"""
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tx_power: Optional[int]
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"""
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TX Power Level of the remote device from the received advertising data or ``None`` if not present.
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.. versionadded:: 0.17
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"""
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rssi: int
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"""
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The Radio Receive Signal Strength (RSSI) in dBm.
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.. versionadded:: 0.19
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"""
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platform_data: Tuple
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"""
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Tuple of platform specific data.
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This is not a stable API. The actual values may change between releases.
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"""
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def __repr__(self) -> str:
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kwargs = []
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if self.local_name:
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kwargs.append(f"local_name={repr(self.local_name)}")
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if self.manufacturer_data:
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kwargs.append(f"manufacturer_data={repr(self.manufacturer_data)}")
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if self.service_data:
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kwargs.append(f"service_data={repr(self.service_data)}")
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if self.service_uuids:
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kwargs.append(f"service_uuids={repr(self.service_uuids)}")
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if self.tx_power is not None:
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kwargs.append(f"tx_power={repr(self.tx_power)}")
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kwargs.append(f"rssi={repr(self.rssi)}")
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return f"AdvertisementData({', '.join(kwargs)})"
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AdvertisementDataCallback = Callable[
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[BLEDevice, AdvertisementData],
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Optional[Coroutine[Any, Any, None]],
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]
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"""
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Type alias for callback called when advertisement data is received.
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"""
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AdvertisementDataFilter = Callable[
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[BLEDevice, AdvertisementData],
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bool,
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]
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"""
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Type alias for an advertisement data filter function.
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Implementations should return ``True`` for matches, otherwise ``False``.
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"""
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class BaseBleakScanner(abc.ABC):
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"""
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Interface for Bleak Bluetooth LE Scanners
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Args:
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detection_callback:
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Optional function that will be called each time a device is
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discovered or advertising data has changed.
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service_uuids:
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Optional list of service UUIDs to filter on. Only advertisements
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containing this advertising data will be received.
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"""
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seen_devices: Dict[str, Tuple[BLEDevice, AdvertisementData]]
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"""
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Map of device identifier to BLEDevice and most recent advertisement data.
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This map must be cleared when scanning starts.
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"""
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def __init__(
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self,
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detection_callback: Optional[AdvertisementDataCallback],
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service_uuids: Optional[List[str]],
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):
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super(BaseBleakScanner, self).__init__()
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self._ad_callbacks: Dict[
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Hashable, Callable[[BLEDevice, AdvertisementData], None]
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] = {}
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"""
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List of callbacks to call when an advertisement is received.
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"""
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if detection_callback is not None:
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self.register_detection_callback(detection_callback)
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self._service_uuids: Optional[List[str]] = (
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[u.lower() for u in service_uuids] if service_uuids is not None else None
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)
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self.seen_devices = {}
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def register_detection_callback(
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self, callback: Optional[AdvertisementDataCallback]
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) -> Callable[[], None]:
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"""
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Register a callback that is called when an advertisement event from the
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OS is received.
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The ``callback`` is a function or coroutine that takes two arguments: :class:`BLEDevice`
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and :class:`AdvertisementData`.
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Args:
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callback: A function, coroutine or ``None``.
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Returns:
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A method that can be called to unregister the callback.
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"""
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error_text = "callback must be callable with 2 parameters"
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if not callable(callback):
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raise TypeError(error_text)
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handler_signature = inspect.signature(callback)
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if len(handler_signature.parameters) != 2:
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raise TypeError(error_text)
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if inspect.iscoroutinefunction(callback):
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def detection_callback(s: BLEDevice, d: AdvertisementData) -> None:
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task = asyncio.create_task(callback(s, d))
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_background_tasks.add(task)
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task.add_done_callback(_background_tasks.discard)
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else:
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detection_callback = callback
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token = object()
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self._ad_callbacks[token] = detection_callback
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def remove() -> None:
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self._ad_callbacks.pop(token, None)
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return remove
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def is_allowed_uuid(self, service_uuids: Optional[List[str]]) -> bool:
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"""
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Check if the advertisement data contains any of the service UUIDs
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matching the filter. If no filter is set, this will always return
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``True``.
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Args:
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service_uuids: The service UUIDs from the advertisement data.
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Returns:
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``True`` if the advertisement data should be allowed or ``False``
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if the advertisement data should be filtered out.
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"""
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# Backends will make best effort to filter out advertisements that
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# don't match the service UUIDs, but if other apps are scanning at the
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# same time or something like that, we may still receive advertisements
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# that don't match. So we need to do more filtering here to get the
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# expected behavior.
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if not self._service_uuids:
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# if there is no filter, everything is allowed
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return True
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if not service_uuids:
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# if there is a filter the advertisement data doesn't contain any
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# service UUIDs, filter it out
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return False
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for uuid in service_uuids:
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if uuid in self._service_uuids:
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# match was found, keep this advertisement
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return True
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# there were no matching service uuids, filter this one out
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return False
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def call_detection_callbacks(
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self, device: BLEDevice, advertisement_data: AdvertisementData
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) -> None:
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"""
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Calls all registered detection callbacks.
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Backend implementations should call this method when an advertisement
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event is received from the OS.
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"""
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for callback in self._ad_callbacks.values():
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callback(device, advertisement_data)
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def create_or_update_device(
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self, address: str, name: str, details: Any, adv: AdvertisementData
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) -> BLEDevice:
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"""
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Creates or updates a device in :attr:`seen_devices`.
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Args:
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address: The Bluetooth address of the device (UUID on macOS).
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name: The OS display name for the device.
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details: The platform-specific handle for the device.
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adv: The most recent advertisement data received.
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Returns:
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The updated device.
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"""
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# for backwards compatibility, see https://github.com/hbldh/bleak/issues/1025
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metadata = dict(
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uuids=adv.service_uuids,
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manufacturer_data=adv.manufacturer_data,
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)
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try:
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device, _ = self.seen_devices[address]
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device.name = name
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device._rssi = adv.rssi
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device._metadata = metadata
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except KeyError:
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device = BLEDevice(
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address,
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name,
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details,
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adv.rssi,
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**metadata,
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)
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self.seen_devices[address] = (device, adv)
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return device
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@abc.abstractmethod
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async def start(self) -> None:
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"""Start scanning for devices"""
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raise NotImplementedError()
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@abc.abstractmethod
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async def stop(self) -> None:
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"""Stop scanning for devices"""
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raise NotImplementedError()
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@abc.abstractmethod
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def set_scanning_filter(self, **kwargs) -> None:
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"""Set scanning filter for the BleakScanner.
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Args:
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**kwargs: The filter details. This will differ a lot between backend implementations.
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"""
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raise NotImplementedError()
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def get_platform_scanner_backend_type() -> Type[BaseBleakScanner]:
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"""
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Gets the platform-specific :class:`BaseBleakScanner` type.
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"""
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if os.environ.get("P4A_BOOTSTRAP") is not None:
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from bleak.backends.p4android.scanner import BleakScannerP4Android
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return BleakScannerP4Android
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if platform.system() == "Linux":
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from bleak.backends.bluezdbus.scanner import BleakScannerBlueZDBus
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return BleakScannerBlueZDBus
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if platform.system() == "Darwin":
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from bleak.backends.corebluetooth.scanner import BleakScannerCoreBluetooth
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return BleakScannerCoreBluetooth
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if platform.system() == "Windows":
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from bleak.backends.winrt.scanner import BleakScannerWinRT
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return BleakScannerWinRT
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raise BleakError(f"Unsupported platform: {platform.system()}")
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