133 lines
4.1 KiB
Python
133 lines
4.1 KiB
Python
# -*- coding: utf-8 -*-
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"""
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Interface class for the Bleak representation of a GATT Characteristic
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Created on 2019-03-19 by hbldh <henrik.blidh@nedomkull.com>
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"""
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import abc
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import enum
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from typing import Any, Callable, List, Union
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from uuid import UUID
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from ..uuids import uuidstr_to_str
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from .descriptor import BleakGATTDescriptor
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class GattCharacteristicsFlags(enum.Enum):
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broadcast = 0x0001
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read = 0x0002
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write_without_response = 0x0004
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write = 0x0008
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notify = 0x0010
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indicate = 0x0020
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authenticated_signed_writes = 0x0040
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extended_properties = 0x0080
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reliable_write = 0x0100
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writable_auxiliaries = 0x0200
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class BleakGATTCharacteristic(abc.ABC):
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"""Interface for the Bleak representation of a GATT Characteristic"""
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def __init__(self, obj: Any, max_write_without_response_size: Callable[[], int]):
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"""
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Args:
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obj:
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A platform-specific object for this characteristic.
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max_write_without_response_size:
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The maximum size in bytes that can be written to the
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characteristic in a single write without response command.
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"""
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self.obj = obj
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self._max_write_without_response_size = max_write_without_response_size
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def __str__(self):
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return f"{self.uuid} (Handle: {self.handle}): {self.description}"
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@property
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@abc.abstractmethod
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def service_uuid(self) -> str:
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"""The UUID of the Service containing this characteristic"""
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raise NotImplementedError()
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@property
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@abc.abstractmethod
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def service_handle(self) -> int:
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"""The integer handle of the Service containing this characteristic"""
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raise NotImplementedError()
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@property
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@abc.abstractmethod
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def handle(self) -> int:
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"""The handle for this characteristic"""
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raise NotImplementedError()
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@property
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@abc.abstractmethod
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def uuid(self) -> str:
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"""The UUID for this characteristic"""
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raise NotImplementedError()
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@property
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def description(self) -> str:
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"""Description for this characteristic"""
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return uuidstr_to_str(self.uuid)
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@property
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@abc.abstractmethod
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def properties(self) -> List[str]:
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"""Properties of this characteristic"""
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raise NotImplementedError()
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@property
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def max_write_without_response_size(self) -> int:
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"""
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Gets the maximum size in bytes that can be used for the *data* argument
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of :meth:`BleakClient.write_gatt_char()` when ``response=False``.
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In rare cases, a device may take a long time to update this value, so
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reading this property may return the default value of ``20`` and reading
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it again after a some time may return the expected higher value.
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If you *really* need to wait for a higher value, you can do something
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like this:
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.. code-block:: python
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async with asyncio.timeout(10):
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while char.max_write_without_response_size == 20:
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await asyncio.sleep(0.5)
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.. warning:: Linux quirk: For BlueZ versions < 5.62, this property
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will always return ``20``.
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.. versionadded:: 0.16
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"""
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# for backwards compatibility
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if isinstance(self._max_write_without_response_size, int):
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return self._max_write_without_response_size
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return self._max_write_without_response_size()
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@property
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@abc.abstractmethod
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def descriptors(self) -> List[BleakGATTDescriptor]:
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"""List of descriptors for this service"""
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raise NotImplementedError()
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@abc.abstractmethod
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def get_descriptor(
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self, specifier: Union[int, str, UUID]
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) -> Union[BleakGATTDescriptor, None]:
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"""Get a descriptor by handle (int) or UUID (str or uuid.UUID)"""
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raise NotImplementedError()
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@abc.abstractmethod
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def add_descriptor(self, descriptor: BleakGATTDescriptor) -> None:
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"""Add a :py:class:`~BleakGATTDescriptor` to the characteristic.
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Should not be used by end user, but rather by `bleak` itself.
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"""
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raise NotImplementedError()
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