hrforward.py

import logging
import asyncio
import threading

from bleak import BleakScanner
#from typing import Any

def uuid16(n):
    return "0000%04X-0000-1000-8000-00805F9B34FB" % n

hrAddress = "[deleted]"

from bless import (
        BlessServer,
        BlessGATTCharacteristic,
        GATTCharacteristicProperties,
        GATTAttributePermissions
        )

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(name=__name__)

async def run(loop):
    # Instantiate the server
    my_service_name = "Heart Service"
    server = BlessServer(name=my_service_name, loop=loop)

    hr_service_uuid = uuid16(0x180d)
    await server.add_new_service(hr_service_uuid)

    measurement_char_uuid = uuid16(0x2a37)
    measurement_flags = GATTCharacteristicProperties.notify
    
    permissions = (
            GATTAttributePermissions.readable |
            GATTAttributePermissions.writeable
            )
    logger.info("adding characteristic")
    await server.add_new_characteristic(
            hr_service_uuid,
            measurement_char_uuid,
            measurement_flags,
            None,
            permissions)
            
    logger.info("waiting for start")

    await server.start()
    
    logger.info("started")
    
    hr_char = server.get_characteristic(measurement_char_uuid)

    def callback(device, advertising_data):
        if device.address == hrAddress.upper():
            try:
                sd = advertising_data.service_data[uuid16(0xFEE0).lower()]
                if len(sd) == 5:
                    hr = sd[4]
                    logger.info("hr = %d" % hr)
                    hr_char.value = bytearray((0,hr))
                    server.update_value(hr_service_uuid, measurement_char_uuid)
            except:
                pass
                
    async with BleakScanner(callback) as scanner:
        await stop_event.wait()    
    
    await server.stop()

loop = asyncio.get_event_loop()
loop.run_until_complete(run(loop))