enable_notifications.py

# -*- coding: utf-8 -*-
"""
Notifications
-------------

Example showing how to add notifications to a characteristic and handle the responses.

Updated on 2019-07-03 by hbldh <henrik.blidh@gmail.com>

"""

import argparse
import asyncio
import logging

from bleak import BleakClient, BleakScanner
from bleak.backends.characteristic import BleakGATTCharacteristic

logger = logging.getLogger(__name__)


def notification_handler(characteristic: BleakGATTCharacteristic, data: bytearray):
    """Simple notification handler which prints the data received."""
    logger.info("%s: %r", characteristic.description, data)


async def main(args: argparse.Namespace):
    logger.info("starting scan...")

    if args.address:
        device = await BleakScanner.find_device_by_address(
            args.address, cb=dict(use_bdaddr=args.macos_use_bdaddr)
        )
        if device is None:
            logger.error("could not find device with address '%s'", args.address)
            return
    else:
        device = await BleakScanner.find_device_by_name(
            args.name, cb=dict(use_bdaddr=args.macos_use_bdaddr)
        )
        if device is None:
            logger.error("could not find device with name '%s'", args.name)
            return

    logger.info("connecting to device...")

    async with BleakClient(device) as client:
        logger.info("Connected")

        await client.start_notify(args.characteristic, notification_handler)
        await asyncio.sleep(5.0)
        await client.stop_notify(args.characteristic)


if __name__ == "__main__":
    parser = argparse.ArgumentParser()

    device_group = parser.add_mutually_exclusive_group(required=True)

    device_group.add_argument(
        "--name",
        metavar="<name>",
        help="the name of the bluetooth device to connect to",
    )
    device_group.add_argument(
        "--address",
        metavar="<address>",
        help="the address of the bluetooth device to connect to",
    )

    parser.add_argument(
        "--macos-use-bdaddr",
        action="store_true",
        help="when true use Bluetooth address instead of UUID on macOS",
    )

    parser.add_argument(
        "characteristic",
        metavar="<notify uuid>",
        help="UUID of a characteristic that supports notifications",
    )

    parser.add_argument(
        "-d",
        "--debug",
        action="store_true",
        help="sets the log level to debug",
    )

    args = parser.parse_args()

    log_level = logging.DEBUG if args.debug else logging.INFO
    logging.basicConfig(
        level=log_level,
        format="%(asctime)-15s %(name)-8s %(levelname)s: %(message)s",
    )

    asyncio.run(main(args))