address PR comments

auracast audio io

apps/auracast.py

@@ -18,14 +18,23 @@
 from __future__ import annotations
 
 import asyncio
+import asyncio.subprocess
+import collections
 import contextlib
 import dataclasses
 import functools
 import logging
 import os
-import wave
-import itertools
-from typing import cast, Any, AsyncGenerator, Coroutine, Dict, Optional, Tuple
+import struct
+from typing import (
+    cast,
+    Any,
+    AsyncGenerator,
+    Coroutine,
+    Deque,
+    Optional,
+    Tuple,
+)
 
 import click
 import pyee
@@ -33,8 +42,11 @@ import pyee
 try:
     import lc3  # type: ignore  # pylint: disable=E0401
 except ImportError as e:
-    raise ImportError("Try `python -m pip install \".[lc3]\"`.") from e
+    raise ImportError(
+        "Try `python -m pip install \"git+https://github.com/google/liblc3.git\"`."
+    ) from e
 
+from bumble.audio import io as audio_io
 from bumble.colors import color
 from bumble import company_ids
 from bumble import core
@@ -48,7 +60,6 @@ import bumble.device
 import bumble.transport
 import bumble.utils
 
-
 # -----------------------------------------------------------------------------
 # Logging
 # -----------------------------------------------------------------------------
@@ -62,6 +73,31 @@ AURACAST_DEFAULT_DEVICE_NAME = 'Bumble Auracast'
 AURACAST_DEFAULT_DEVICE_ADDRESS = hci.Address('F0:F1:F2:F3:F4:F5')
 AURACAST_DEFAULT_SYNC_TIMEOUT = 5.0
 AURACAST_DEFAULT_ATT_MTU = 256
+AURACAST_DEFAULT_FRAME_DURATION = 10000
+AURACAST_DEFAULT_SAMPLE_RATE = 48000
+AURACAST_DEFAULT_TRANSMIT_BITRATE = 80000
+
+
+# -----------------------------------------------------------------------------
+# Utils
+# -----------------------------------------------------------------------------
+def codec_config_string(
+    codec_config: bap.CodecSpecificConfiguration, indent: str
+) -> str:
+    lines = []
+    if codec_config.sampling_frequency is not None:
+        lines.append(f'Sampling Frequency: {codec_config.sampling_frequency.hz} hz')
+    if codec_config.frame_duration is not None:
+        lines.append(f'Frame Duration:     {codec_config.frame_duration.us} µs')
+    if codec_config.octets_per_codec_frame is not None:
+        lines.append(f'Frame Size:         {codec_config.octets_per_codec_frame} bytes')
+    if codec_config.codec_frames_per_sdu is not None:
+        lines.append(f'Frames Per SDU:     {codec_config.codec_frames_per_sdu}')
+    if codec_config.audio_channel_allocation is not None:
+        lines.append(
+            f'Audio Location:     {codec_config.audio_channel_allocation.name}'
+        )
+    return '\n'.join(indent + line for line in lines)
 
 
 # -----------------------------------------------------------------------------
@@ -156,18 +192,17 @@ class BroadcastScanner(pyee.EventEmitter):
             if self.public_broadcast_announcement:
                 print(
                     f'  {color("Features", "cyan")}:     '
-                    f'{self.public_broadcast_announcement.features}'
-                )
-                print(
-                    f'  {color("Metadata", "cyan")}:     '
-                    f'{self.public_broadcast_announcement.metadata}'
+                    f'{self.public_broadcast_announcement.features.name}'
                 )
+                print(f'  {color("Metadata", "cyan")}:')
+                print(self.public_broadcast_announcement.metadata.pretty_print('    '))
 
             if self.basic_audio_announcement:
                 print(color('  Audio:', 'cyan'))
                 print(
                     color('    Presentation Delay:', 'magenta'),
                     self.basic_audio_announcement.presentation_delay,
+                    "µs",
                 )
                 for subgroup in self.basic_audio_announcement.subgroups:
                     print(color('    Subgroup:', 'magenta'))
@@ -184,17 +219,22 @@ class BroadcastScanner(pyee.EventEmitter):
                         color('        Vendor Specific Codec ID:', 'green'),
                         subgroup.codec_id.vendor_specific_codec_id,
                     )
+                    print(color('      Codec Config:', 'yellow'))
                     print(
-                        color('      Codec Config:', 'yellow'),
-                        subgroup.codec_specific_configuration,
+                        codec_config_string(
+                            subgroup.codec_specific_configuration, '        '
+                        ),
                     )
-                    print(color('      Metadata:    ', 'yellow'), subgroup.metadata)
+                    print(color('      Metadata:    ', 'yellow'))
+                    print(subgroup.metadata.pretty_print('        '))
 
                     for bis in subgroup.bis:
                         print(color(f'      BIS [{bis.index}]:', 'yellow'))
+                        print(color('       Codec Config:', 'green'))
                         print(
-                            color('       Codec Config:', 'green'),
-                            bis.codec_specific_configuration,
+                            codec_config_string(
+                                bis.codec_specific_configuration, '         '
+                            ),
                         )
 
             if self.biginfo:
@@ -482,19 +522,24 @@ async def run_assist(
             return
 
         # Subscribe to and read the broadcast receive state characteristics
+        def on_broadcast_receive_state_update(
+            value: bass.BroadcastReceiveState, index: int
+        ) -> None:
+            print(
+                f"{color(f'Broadcast Receive State Update [{index}]:', 'green')} {value}"
+            )
+
         for i, broadcast_receive_state in enumerate(
             bass_client.broadcast_receive_states
         ):
             try:
                 await broadcast_receive_state.subscribe(
-                    lambda value, i=i: print(
-                        f"{color(f'Broadcast Receive State Update [{i}]:', 'green')} {value}"
-                    )
+                    functools.partial(on_broadcast_receive_state_update, index=i)
                 )
             except core.ProtocolError as error:
                 print(
                     color(
-                        f'!!! Failed to subscribe to Broadcast Receive State characteristic:',
+                        '!!! Failed to subscribe to Broadcast Receive State characteristic',
                         'red',
                     ),
                     error,
@@ -625,11 +670,20 @@ async def run_pair(transport: str, address: str) -> None:
 
 async def run_receive(
     transport: str,
-    broadcast_id: int,
+    broadcast_id: Optional[int],
+    output: str,
     broadcast_code: str | None,
     sync_timeout: float,
     subgroup_index: int,
 ) -> None:
+    # Run a pre-flight check for the output.
+    try:
+        if not audio_io.check_audio_output(output):
+            return
+    except ValueError as error:
+        print(error)
+        return
+
     async with create_device(transport) as device:
         if not device.supports_le_periodic_advertising:
             print(color('Periodic advertising not supported', 'red'))
@@ -643,7 +697,7 @@ async def run_receive(
         def on_new_broadcast(broadcast: BroadcastScanner.Broadcast) -> None:
             if scan_result.done():
                 return
-            if broadcast.broadcast_id == broadcast_id:
+            if broadcast_id is None or broadcast.broadcast_id == broadcast_id:
                 scan_result.set_result(broadcast)
 
         scanner.on('new_broadcast', on_new_broadcast)
@@ -694,57 +748,95 @@ async def run_receive(
             sample_rate_hz=sampling_frequency.hz,
             num_channels=num_bis,
         )
-        sdus = [b''] * num_bis
-        subprocess = await asyncio.create_subprocess_shell(
-            f'stdbuf -i0 ffplay -ar {sampling_frequency.hz} -ac {num_bis} -f f32le pipe:0',
-            stdin=asyncio.subprocess.PIPE,
-            stdout=asyncio.subprocess.PIPE,
-            stderr=asyncio.subprocess.PIPE,
-        )
-        for i, bis_link in enumerate(big_sync.bis_links):
-            print(f'Setup ISO for BIS {bis_link.handle}')
+        lc3_queues: list[Deque[bytes]] = [collections.deque() for i in range(num_bis)]
+        packet_stats = [0, 0]
 
-            def sink(index: int, packet: hci.HCI_IsoDataPacket):
-                nonlocal sdus
-                sdus[index] = packet.iso_sdu_fragment
-                if all(sdus) and subprocess.stdin:
-                    subprocess.stdin.write(decoder.decode(b''.join(sdus)).tobytes())
-                    sdus = [b''] * num_bis
-
-            bis_link.sink = functools.partial(sink, i)
-            await bis_link.setup_data_path(
-                direction=bis_link.Direction.CONTROLLER_TO_HOST
+        audio_output = await audio_io.create_audio_output(output)
+        # This try should be replaced with contextlib.aclosing() when python 3.9 is no
+        # longer needed.
+        try:
+            await audio_output.open(
+                audio_io.PcmFormat(
+                    audio_io.PcmFormat.Endianness.LITTLE,
+                    audio_io.PcmFormat.SampleType.FLOAT32,
+                    sampling_frequency.hz,
+                    num_bis,
+                )
             )
 
-        terminated = asyncio.Event()
-        big_sync.on(big_sync.Event.TERMINATION, lambda _: terminated.set())
-        await terminated.wait()
+            def sink(queue: Deque[bytes], packet: hci.HCI_IsoDataPacket):
+                # TODO: re-assemble fragments and detect errors
+                queue.append(packet.iso_sdu_fragment)
+
+                while all(lc3_queues):
+                    # This assumes SDUs contain one LC3 frame each, which may not
+                    # be correct for all cases. TODO: revisit this assumption.
+                    frame = b''.join([lc3_queue.popleft() for lc3_queue in lc3_queues])
+                    if not frame:
+                        print(color('!!! received empty frame', 'red'))
+                        continue
+
+                    packet_stats[0] += len(frame)
+                    packet_stats[1] += 1
+                    print(
+                        f'\rRECEIVED: {packet_stats[0]} bytes in '
+                        f'{packet_stats[1]} packets',
+                        end='',
+                    )
+
+                    try:
+                        pcm = decoder.decode(frame).tobytes()
+                    except lc3.BaseError as error:
+                        print(color(f'!!! LC3 decoding error: {error}'))
+                        continue
+
+                    audio_output.write(pcm)
+
+            for i, bis_link in enumerate(big_sync.bis_links):
+                print(f'Setup ISO for BIS {bis_link.handle}')
+                bis_link.sink = functools.partial(sink, lc3_queues[i])
+                await device.send_command(
+                    hci.HCI_LE_Setup_ISO_Data_Path_Command(
+                        connection_handle=bis_link.handle,
+                        data_path_direction=hci.HCI_LE_Setup_ISO_Data_Path_Command.Direction.CONTROLLER_TO_HOST,
+                        data_path_id=0,
+                        codec_id=hci.CodingFormat(codec_id=hci.CodecID.TRANSPARENT),
+                        controller_delay=0,
+                        codec_configuration=b'',
+                    ),
+                    check_result=True,
+                )
+
+            terminated = asyncio.Event()
+            big_sync.on(big_sync.Event.TERMINATION, lambda _: terminated.set())
+            await terminated.wait()
+        finally:
+            await audio_output.aclose()
 
 
-async def run_broadcast(
-    transport: str, broadcast_id: int, broadcast_code: str | None, wav_file_path: str
+async def run_transmit(
+    transport: str,
+    broadcast_id: int,
+    broadcast_code: str | None,
+    broadcast_name: str,
+    bitrate: int,
+    manufacturer_data: tuple[int, bytes] | None,
+    input: str,
+    input_format: str,
 ) -> None:
+    # Run a pre-flight check for the input.
+    try:
+        if not audio_io.check_audio_input(input):
+            return
+    except ValueError as error:
+        print(error)
+        return
+
     async with create_device(transport) as device:
         if not device.supports_le_periodic_advertising:
             print(color('Periodic advertising not supported', 'red'))
             return
 
-        with wave.open(wav_file_path, 'rb') as wav:
-            print('Encoding wav file into lc3...')
-            encoder = lc3.Encoder(
-                frame_duration_us=10000,
-                sample_rate_hz=48000,
-                num_channels=2,
-                input_sample_rate_hz=wav.getframerate(),
-            )
-            frames = list[bytes]()
-            while pcm := wav.readframes(encoder.get_frame_samples()):
-                frames.append(
-                    encoder.encode(pcm, num_bytes=200, bit_depth=wav.getsampwidth() * 8)
-                )
-            del encoder
-            print('Encoding complete.')
-
         basic_audio_announcement = bap.BasicAudioAnnouncement(
             presentation_delay=40000,
             subgroups=[
@@ -783,7 +875,23 @@ async def run_broadcast(
             ],
         )
         broadcast_audio_announcement = bap.BroadcastAudioAnnouncement(broadcast_id)
-        print('Start Advertising')
+
+        advertising_manufacturer_data = (
+            b''
+            if manufacturer_data is None
+            else bytes(
+                core.AdvertisingData(
+                    [
+                        (
+                            core.AdvertisingData.MANUFACTURER_SPECIFIC_DATA,
+                            struct.pack('<H', manufacturer_data[0])
+                            + manufacturer_data[1],
+                        )
+                    ]
+                )
+            )
+        )
+
         advertising_set = await device.create_advertising_set(
             advertising_parameters=bumble.device.AdvertisingParameters(
                 advertising_event_properties=bumble.device.AdvertisingEventProperties(
@@ -796,9 +904,10 @@ async def run_broadcast(
                 broadcast_audio_announcement.get_advertising_data()
                 + bytes(
                     core.AdvertisingData(
-                        [(core.AdvertisingData.BROADCAST_NAME, b'Bumble Auracast')]
+                        [(core.AdvertisingData.BROADCAST_NAME, broadcast_name.encode())]
                     )
                 )
+                + advertising_manufacturer_data
             ),
             periodic_advertising_parameters=bumble.device.PeriodicAdvertisingParameters(
                 periodic_advertising_interval_min=80,
@@ -808,47 +917,83 @@ async def run_broadcast(
             auto_restart=True,
             auto_start=True,
         )
+
         print('Start Periodic Advertising')
         await advertising_set.start_periodic()
-        print('Setup BIG')
-        big = await device.create_big(
-            advertising_set,
-            parameters=bumble.device.BigParameters(
-                num_bis=2,
-                sdu_interval=10000,
-                max_sdu=100,
-                max_transport_latency=65,
-                rtn=4,
-                broadcast_code=(
-                    bytes.fromhex(broadcast_code) if broadcast_code else None
-                ),
-            ),
-        )
-        print('Setup ISO Data Path')
 
-        def on_flow(packet_queue):
+        audio_input = await audio_io.create_audio_input(input, input_format)
+        pcm_format = await audio_input.open()
+        # This try should be replaced with contextlib.aclosing() when python 3.9 is no
+        # longer needed.
+        try:
+            if pcm_format.channels != 2:
+                print("Only 2 channels PCM configurations are supported")
+                return
+            if pcm_format.sample_type == audio_io.PcmFormat.SampleType.INT16:
+                pcm_bit_depth = 16
+            elif pcm_format.sample_type == audio_io.PcmFormat.SampleType.FLOAT32:
+                pcm_bit_depth = None
+            else:
+                print("Only INT16 and FLOAT32 sample types are supported")
+                return
+
+            encoder = lc3.Encoder(
+                frame_duration_us=AURACAST_DEFAULT_FRAME_DURATION,
+                sample_rate_hz=AURACAST_DEFAULT_SAMPLE_RATE,
+                num_channels=pcm_format.channels,
+                input_sample_rate_hz=pcm_format.sample_rate,
+            )
+            lc3_frame_samples = encoder.get_frame_samples()
+            lc3_frame_size = encoder.get_frame_bytes(bitrate)
             print(
-                f'\rPACKETS: pending={packet_queue.pending}, '
-                f'queued={packet_queue.queued}, completed={packet_queue.completed}',
-                end='',
+                f'Encoding with {lc3_frame_samples} '
+                f'PCM samples per {lc3_frame_size} byte frame'
             )
 
-        packet_queue = None
-        for bis_link in big.bis_links:
-            await bis_link.setup_data_path(
-                direction=bis_link.Direction.HOST_TO_CONTROLLER
+            print('Setup BIG')
+            big = await device.create_big(
+                advertising_set,
+                parameters=bumble.device.BigParameters(
+                    num_bis=pcm_format.channels,
+                    sdu_interval=AURACAST_DEFAULT_FRAME_DURATION,
+                    max_sdu=lc3_frame_size,
+                    max_transport_latency=65,
+                    rtn=4,
+                    broadcast_code=(
+                        bytes.fromhex(broadcast_code) if broadcast_code else None
+                    ),
+                ),
             )
-            if packet_queue is None:
-                packet_queue = bis_link.data_packet_queue
 
-        if packet_queue:
-            packet_queue.on('flow', lambda: on_flow(packet_queue))
+            iso_queues = [
+                bumble.device.IsoPacketStream(big.bis_links[0], 64),
+                bumble.device.IsoPacketStream(big.bis_links[1], 64),
+            ]
 
-        for frame in itertools.cycle(frames):
-            mid = len(frame) // 2
-            big.bis_links[0].write(frame[:mid])
-            big.bis_links[1].write(frame[mid:])
-            await asyncio.sleep(0.009)
+            def on_flow():
+                data_packet_queue = iso_queues[0].data_packet_queue
+                print(
+                    f'\rPACKETS: pending={data_packet_queue.pending}, '
+                    f'queued={data_packet_queue.queued}, '
+                    f'completed={data_packet_queue.completed}',
+                    end='',
+                )
+
+            iso_queues[0].data_packet_queue.on('flow', on_flow)
+
+            frame_count = 0
+            async for pcm_frame in audio_input.frames(lc3_frame_samples):
+                lc3_frame = encoder.encode(
+                    pcm_frame, num_bytes=2 * lc3_frame_size, bit_depth=pcm_bit_depth
+                )
+
+                mid = len(lc3_frame) // 2
+                await iso_queues[0].write(lc3_frame[:mid])
+                await iso_queues[1].write(lc3_frame[mid:])
+
+                frame_count += 1
+        finally:
+            await audio_input.aclose()
 
 
 def run_async(async_command: Coroutine) -> None:
@@ -917,7 +1062,7 @@ def scan(ctx, filter_duplicates, sync_timeout, transport):
 @click.argument('address')
 @click.pass_context
 def assist(ctx, broadcast_name, source_id, command, transport, address):
-    """Scan for broadcasts on behalf of a audio server"""
+    """Scan for broadcasts on behalf of an audio server"""
     run_async(run_assist(broadcast_name, source_id, command, transport, address))
 
 
@@ -932,7 +1077,24 @@ def pair(ctx, transport, address):
 
 @auracast.command('receive')
 @click.argument('transport')
-@click.argument('broadcast_id', type=int)
+@click.argument(
+    'broadcast_id',
+    type=int,
+    required=False,
+)
+@click.option(
+    '--output',
+    default='device',
+    help=(
+        "Audio output. "
+        "'device' -> use the host's default sound output device, "
+        "'device:<DEVICE_ID>' -> use one of the  host's sound output device "
+        "(specify 'device:?' to get a list of available sound output devices), "
+        "'stdout' -> send audio to stdout, "
+        "'file:<filename> -> write audio to a raw float32 PCM file, "
+        "'ffplay' -> pipe the audio to ffplay"
+    ),
+)
 @click.option(
     '--broadcast-code',
     metavar='BROADCAST_CODE',
@@ -954,16 +1116,57 @@ def pair(ctx, transport, address):
     help='Index of Subgroup',
 )
 @click.pass_context
-def receive(ctx, transport, broadcast_id, broadcast_code, sync_timeout, subgroup):
+def receive(
+    ctx,
+    transport,
+    broadcast_id,
+    output,
+    broadcast_code,
+    sync_timeout,
+    subgroup,
+):
     """Receive a broadcast source"""
     run_async(
-        run_receive(transport, broadcast_id, broadcast_code, sync_timeout, subgroup)
+        run_receive(
+            transport,
+            broadcast_id,
+            output,
+            broadcast_code,
+            sync_timeout,
+            subgroup,
+        )
     )
 
 
-@auracast.command('broadcast')
+@auracast.command('transmit')
 @click.argument('transport')
-@click.argument('wav_file_path', type=str)
+@click.option(
+    '--input',
+    required=True,
+    help=(
+        "Audio input. "
+        "'device' -> use the host's default sound input device, "
+        "'device:<DEVICE_ID>' -> use one of the host's sound input devices "
+        "(specify 'device:?' to get a list of available sound input devices), "
+        "'stdin' -> receive audio from stdin as int16 PCM, "
+        "'file:<filename> -> read audio from a .wav or raw int16 PCM file. "
+        "(The file: prefix may be omitted if the file path does not start with "
+        "the substring 'device:' or 'file:' and is not 'stdin')"
+    ),
+)
+@click.option(
+    '--input-format',
+    metavar="FORMAT",
+    default='auto',
+    help=(
+        "Audio input format. "
+        "Use 'auto' for .wav files, or for the default setting with the devices. "
+        "For other inputs, the format is specified as "
+        "<sample-type>,<sample-rate>,<channels> (supported <sample-type>: 'int16le' "
+        "for 16-bit signed integers with little-endian byte order or 'float32le' for "
+        "32-bit floating point with little-endian byte order)"
+    ),
+)
 @click.option(
     '--broadcast-id',
     metavar='BROADCAST_ID',
@@ -974,18 +1177,60 @@ def receive(ctx, transport, broadcast_id, broadcast_code, sync_timeout, subgroup
 @click.option(
     '--broadcast-code',
     metavar='BROADCAST_CODE',
-    type=str,
     help='Broadcast encryption code in hex format',
 )
+@click.option(
+    '--broadcast-name',
+    metavar='BROADCAST_NAME',
+    default='Bumble Auracast',
+    help='Broadcast name',
+)
+@click.option(
+    '--bitrate',
+    type=int,
+    default=AURACAST_DEFAULT_TRANSMIT_BITRATE,
+    help='Bitrate, per channel, in bps',
+)
+@click.option(
+    '--manufacturer-data',
+    metavar='VENDOR-ID:DATA-HEX',
+    help='Manufacturer data (specify as <vendor-id>:<data-hex>)',
+)
 @click.pass_context
-def broadcast(ctx, transport, broadcast_id, broadcast_code, wav_file_path):
-    """Start a broadcast as a source."""
+def transmit(
+    ctx,
+    transport,
+    broadcast_id,
+    broadcast_code,
+    manufacturer_data,
+    broadcast_name,
+    bitrate,
+    input,
+    input_format,
+):
+    """Transmit a broadcast source"""
+    if manufacturer_data:
+        vendor_id_str, data_hex = manufacturer_data.split(':')
+        vendor_id = int(vendor_id_str)
+        data = bytes.fromhex(data_hex)
+        manufacturer_data_tuple = (vendor_id, data)
+    else:
+        manufacturer_data_tuple = None
+
+    if (input == 'device' or input.startswith('device:')) and input_format == 'auto':
+        # Use a default format for device inputs
+        input_format = 'int16le,48000,1'
+
     run_async(
-        run_broadcast(
+        run_transmit(
             transport=transport,
             broadcast_id=broadcast_id,
             broadcast_code=broadcast_code,
-            wav_file_path=wav_file_path,
+            broadcast_name=broadcast_name,
+            bitrate=bitrate,
+            manufacturer_data=manufacturer_data_tuple,
+            input=input,
+            input_format=input_format,
         )
     )
 

apps/bench.py

@@ -16,6 +16,7 @@
 # Imports
 # -----------------------------------------------------------------------------
 import asyncio
+import dataclasses
 import enum
 import logging
 import os
@@ -97,34 +98,6 @@ DEFAULT_RFCOMM_MTU = 2048
 # -----------------------------------------------------------------------------
 # Utils
 # -----------------------------------------------------------------------------
-def parse_packet(packet):
-    if len(packet) < 1:
-        logging.info(
-            color(f'!!! Packet too short (got {len(packet)} bytes, need >= 1)', 'red')
-        )
-        raise ValueError('packet too short')
-
-    try:
-        packet_type = PacketType(packet[0])
-    except ValueError:
-        logging.info(color(f'!!! Invalid packet type 0x{packet[0]:02X}', 'red'))
-        raise
-
-    return (packet_type, packet[1:])
-
-
-def parse_packet_sequence(packet_data):
-    if len(packet_data) < 5:
-        logging.info(
-            color(
-                f'!!!Packet too short (got {len(packet_data)} bytes, need >= 5)',
-                'red',
-            )
-        )
-        raise ValueError('packet too short')
-    return struct.unpack_from('>bI', packet_data, 0)
-
-
 def le_phy_name(phy_id):
     return {HCI_LE_1M_PHY: '1M', HCI_LE_2M_PHY: '2M', HCI_LE_CODED_PHY: 'CODED'}.get(
         phy_id, HCI_Constant.le_phy_name(phy_id)
@@ -225,13 +198,135 @@ async def switch_roles(connection, role):
             logging.info(f'{color("### Role switch failed:", "red")} {error}')
 
 
-class PacketType(enum.IntEnum):
-    RESET = 0
-    SEQUENCE = 1
-    ACK = 2
+# -----------------------------------------------------------------------------
+# Packet
+# -----------------------------------------------------------------------------
+@dataclasses.dataclass
+class Packet:
+    class PacketType(enum.IntEnum):
+        RESET = 0
+        SEQUENCE = 1
+        ACK = 2
+
+    class PacketFlags(enum.IntFlag):
+        LAST = 1
+
+    packet_type: PacketType
+    flags: PacketFlags = PacketFlags(0)
+    sequence: int = 0
+    timestamp: int = 0
+    payload: bytes = b""
+
+    @classmethod
+    def from_bytes(cls, data: bytes):
+        if len(data) < 1:
+            logging.warning(
+                color(f'!!! Packet too short (got {len(data)} bytes, need >= 1)', 'red')
+            )
+            raise ValueError('packet too short')
+
+        try:
+            packet_type = cls.PacketType(data[0])
+        except ValueError:
+            logging.warning(color(f'!!! Invalid packet type 0x{data[0]:02X}', 'red'))
+            raise
+
+        if packet_type == cls.PacketType.RESET:
+            return cls(packet_type)
+
+        flags = cls.PacketFlags(data[1])
+        (sequence,) = struct.unpack_from("<I", data, 2)
+
+        if packet_type == cls.PacketType.ACK:
+            if len(data) < 6:
+                logging.warning(
+                    color(
+                        f'!!! Packet too short (got {len(data)} bytes, need >= 6)',
+                        'red',
+                    )
+                )
+            return cls(packet_type, flags, sequence)
+
+        if len(data) < 10:
+            logging.warning(
+                color(
+                    f'!!! Packet too short (got {len(data)} bytes, need >= 10)', 'red'
+                )
+            )
+            raise ValueError('packet too short')
+
+        (timestamp,) = struct.unpack_from("<I", data, 6)
+        return cls(packet_type, flags, sequence, timestamp, data[10:])
+
+    def __bytes__(self):
+        if self.packet_type == self.PacketType.RESET:
+            return bytes([self.packet_type])
+
+        if self.packet_type == self.PacketType.ACK:
+            return struct.pack("<BBI", self.packet_type, self.flags, self.sequence)
+
+        return (
+            struct.pack(
+                "<BBII", self.packet_type, self.flags, self.sequence, self.timestamp
+            )
+            + self.payload
+        )
 
 
-PACKET_FLAG_LAST = 1
+# -----------------------------------------------------------------------------
+# Jitter Stats
+# -----------------------------------------------------------------------------
+class JitterStats:
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        self.packets = []
+        self.receive_times = []
+        self.jitter = []
+
+    def on_packet_received(self, packet):
+        now = time.time()
+        self.packets.append(packet)
+        self.receive_times.append(now)
+
+        if packet.timestamp and len(self.packets) > 1:
+            expected_time = (
+                self.receive_times[0]
+                + (packet.timestamp - self.packets[0].timestamp) / 1000000
+            )
+            jitter = now - expected_time
+        else:
+            jitter = 0.0
+
+        self.jitter.append(jitter)
+        return jitter
+
+    def show_stats(self):
+        if len(self.jitter) < 3:
+            return
+        average = sum(self.jitter) / len(self.jitter)
+        adjusted = [jitter - average for jitter in self.jitter]
+
+        log_stats('Jitter (signed)', adjusted, 3)
+        log_stats('Jitter (absolute)', [abs(jitter) for jitter in adjusted], 3)
+
+        # Show a histogram
+        bin_count = 20
+        bins = [0] * bin_count
+        interval_min = min(adjusted)
+        interval_max = max(adjusted)
+        interval_range = interval_max - interval_min
+        bin_thresholds = [
+            interval_min + i * (interval_range / bin_count) for i in range(bin_count)
+        ]
+        for jitter in adjusted:
+            for i in reversed(range(bin_count)):
+                if jitter >= bin_thresholds[i]:
+                    bins[i] += 1
+                    break
+        for i in range(bin_count):
+            logging.info(f'@@@ >= {bin_thresholds[i]:.4f}: {bins[i]}')
 
 
 # -----------------------------------------------------------------------------
@@ -281,19 +376,37 @@ class Sender:
                 await asyncio.sleep(self.tx_start_delay)
 
             logging.info(color('=== Sending RESET', 'magenta'))
-            await self.packet_io.send_packet(bytes([PacketType.RESET]))
+            await self.packet_io.send_packet(
+                bytes(Packet(packet_type=Packet.PacketType.RESET))
+            )
+
             self.start_time = time.time()
             self.bytes_sent = 0
             for tx_i in range(self.tx_packet_count):
-                packet_flags = (
-                    PACKET_FLAG_LAST if tx_i == self.tx_packet_count - 1 else 0
+                if self.pace > 0:
+                    # Wait until it is time to send the next packet
+                    target_time = self.start_time + (tx_i * self.pace / 1000)
+                    now = time.time()
+                    if now < target_time:
+                        await asyncio.sleep(target_time - now)
+                else:
+                    await self.packet_io.drain()
+
+                packet = bytes(
+                    Packet(
+                        packet_type=Packet.PacketType.SEQUENCE,
+                        flags=(
+                            Packet.PacketFlags.LAST
+                            if tx_i == self.tx_packet_count - 1
+                            else 0
+                        ),
+                        sequence=tx_i,
+                        timestamp=int((time.time() - self.start_time) * 1000000),
+                        payload=bytes(
+                            self.tx_packet_size - 10 - self.packet_io.overhead_size
+                        ),
+                    )
                 )
-                packet = struct.pack(
-                    '>bbI',
-                    PacketType.SEQUENCE,
-                    packet_flags,
-                    tx_i,
-                ) + bytes(self.tx_packet_size - 6 - self.packet_io.overhead_size)
                 logging.info(
                     color(
                         f'Sending packet {tx_i}: {self.tx_packet_size} bytes', 'yellow'
@@ -302,14 +415,6 @@ class Sender:
                 self.bytes_sent += len(packet)
                 await self.packet_io.send_packet(packet)
 
-                if self.pace is None:
-                    continue
-
-                if self.pace > 0:
-                    await asyncio.sleep(self.pace / 1000)
-                else:
-                    await self.packet_io.drain()
-
             await self.done.wait()
 
             run_counter = f'[{run + 1} of {self.repeat + 1}]' if self.repeat else ''
@@ -321,13 +426,13 @@ class Sender:
         if self.repeat:
             logging.info(color('--- End of runs', 'blue'))
 
-    def on_packet_received(self, packet):
+    def on_packet_received(self, data):
         try:
-            packet_type, _ = parse_packet(packet)
+            packet = Packet.from_bytes(data)
         except ValueError:
             return
 
-        if packet_type == PacketType.ACK:
+        if packet.packet_type == Packet.PacketType.ACK:
             elapsed = time.time() - self.start_time
             average_tx_speed = self.bytes_sent / elapsed
             self.stats.append(average_tx_speed)
@@ -350,52 +455,53 @@ class Receiver:
     last_timestamp: float
 
     def __init__(self, packet_io, linger):
-        self.reset()
+        self.jitter_stats = JitterStats()
         self.packet_io = packet_io
         self.packet_io.packet_listener = self
         self.linger = linger
         self.done = asyncio.Event()
+        self.reset()
 
     def reset(self):
         self.expected_packet_index = 0
         self.measurements = [(time.time(), 0)]
         self.total_bytes_received = 0
+        self.jitter_stats.reset()
 
-    def on_packet_received(self, packet):
+    def on_packet_received(self, data):
         try:
-            packet_type, packet_data = parse_packet(packet)
+            packet = Packet.from_bytes(data)
         except ValueError:
+            logging.exception("invalid packet")
             return
 
-        if packet_type == PacketType.RESET:
+        if packet.packet_type == Packet.PacketType.RESET:
             logging.info(color('=== Received RESET', 'magenta'))
             self.reset()
             return
 
-        try:
-            packet_flags, packet_index = parse_packet_sequence(packet_data)
-        except ValueError:
-            return
+        jitter = self.jitter_stats.on_packet_received(packet)
         logging.info(
-            f'<<< Received packet {packet_index}: '
-            f'flags=0x{packet_flags:02X}, '
-            f'{len(packet) + self.packet_io.overhead_size} bytes'
+            f'<<< Received packet {packet.sequence}: '
+            f'flags={packet.flags}, '
+            f'jitter={jitter:.4f}, '
+            f'{len(data) + self.packet_io.overhead_size} bytes',
         )
 
-        if packet_index != self.expected_packet_index:
+        if packet.sequence != self.expected_packet_index:
             logging.info(
                 color(
                     f'!!! Unexpected packet, expected {self.expected_packet_index} '
-                    f'but received {packet_index}'
+                    f'but received {packet.sequence}'
                 )
             )
 
         now = time.time()
         elapsed_since_start = now - self.measurements[0][0]
         elapsed_since_last = now - self.measurements[-1][0]
-        self.measurements.append((now, len(packet)))
-        self.total_bytes_received += len(packet)
-        instant_rx_speed = len(packet) / elapsed_since_last
+        self.measurements.append((now, len(data)))
+        self.total_bytes_received += len(data)
+        instant_rx_speed = len(data) / elapsed_since_last
         average_rx_speed = self.total_bytes_received / elapsed_since_start
         window = self.measurements[-64:]
         windowed_rx_speed = sum(measurement[1] for measurement in window[1:]) / (
@@ -411,15 +517,17 @@ class Receiver:
             )
         )
 
-        self.expected_packet_index = packet_index + 1
+        self.expected_packet_index = packet.sequence + 1
 
-        if packet_flags & PACKET_FLAG_LAST:
+        if packet.flags & Packet.PacketFlags.LAST:
             AsyncRunner.spawn(
                 self.packet_io.send_packet(
-                    struct.pack('>bbI', PacketType.ACK, packet_flags, packet_index)
+                    bytes(Packet(Packet.PacketType.ACK, packet.flags, packet.sequence))
                 )
             )
             logging.info(color('@@@ Received last packet', 'green'))
+            self.jitter_stats.show_stats()
+
             if not self.linger:
                 self.done.set()
 
@@ -479,25 +587,32 @@ class Ping:
                 await asyncio.sleep(self.tx_start_delay)
 
             logging.info(color('=== Sending RESET', 'magenta'))
-            await self.packet_io.send_packet(bytes([PacketType.RESET]))
+            await self.packet_io.send_packet(bytes(Packet(Packet.PacketType.RESET)))
 
-            packet_interval = self.pace / 1000
             start_time = time.time()
             self.next_expected_packet_index = 0
             for i in range(self.tx_packet_count):
-                target_time = start_time + (i * packet_interval)
+                target_time = start_time + (i * self.pace / 1000)
                 now = time.time()
                 if now < target_time:
                     await asyncio.sleep(target_time - now)
+                    now = time.time()
 
-                packet = struct.pack(
-                    '>bbI',
-                    PacketType.SEQUENCE,
-                    (PACKET_FLAG_LAST if i == self.tx_packet_count - 1 else 0),
-                    i,
-                ) + bytes(self.tx_packet_size - 6)
+                packet = bytes(
+                    Packet(
+                        packet_type=Packet.PacketType.SEQUENCE,
+                        flags=(
+                            Packet.PacketFlags.LAST
+                            if i == self.tx_packet_count - 1
+                            else 0
+                        ),
+                        sequence=i,
+                        timestamp=int((now - start_time) * 1000000),
+                        payload=bytes(self.tx_packet_size - 10),
+                    )
+                )
                 logging.info(color(f'Sending packet {i}', 'yellow'))
-                self.ping_times.append(time.time())
+                self.ping_times.append(now)
                 await self.packet_io.send_packet(packet)
 
             await self.done.wait()
@@ -531,40 +646,35 @@ class Ping:
         if self.repeat:
             logging.info(color('--- End of runs', 'blue'))
 
-    def on_packet_received(self, packet):
+    def on_packet_received(self, data):
         try:
-            packet_type, packet_data = parse_packet(packet)
+            packet = Packet.from_bytes(data)
         except ValueError:
             return
 
-        try:
-            packet_flags, packet_index = parse_packet_sequence(packet_data)
-        except ValueError:
-            return
-
-        if packet_type == PacketType.ACK:
-            elapsed = time.time() - self.ping_times[packet_index]
+        if packet.packet_type == Packet.PacketType.ACK:
+            elapsed = time.time() - self.ping_times[packet.sequence]
             rtt = elapsed * 1000
             self.rtts.append(rtt)
             logging.info(
                 color(
-                    f'<<< Received ACK [{packet_index}], RTT={rtt:.2f}ms',
+                    f'<<< Received ACK [{packet.sequence}], RTT={rtt:.2f}ms',
                     'green',
                 )
             )
 
-            if packet_index == self.next_expected_packet_index:
+            if packet.sequence == self.next_expected_packet_index:
                 self.next_expected_packet_index += 1
             else:
                 logging.info(
                     color(
                         f'!!! Unexpected packet, '
                         f'expected {self.next_expected_packet_index} '
-                        f'but received {packet_index}'
+                        f'but received {packet.sequence}'
                     )
                 )
 
-        if packet_flags & PACKET_FLAG_LAST:
+        if packet.flags & Packet.PacketFlags.LAST:
             self.done.set()
             return
 
@@ -576,89 +686,56 @@ class Pong:
     expected_packet_index: int
 
     def __init__(self, packet_io, linger):
-        self.reset()
+        self.jitter_stats = JitterStats()
         self.packet_io = packet_io
         self.packet_io.packet_listener = self
         self.linger = linger
         self.done = asyncio.Event()
+        self.reset()
 
     def reset(self):
         self.expected_packet_index = 0
-        self.receive_times = []
-
-    def on_packet_received(self, packet):
-        self.receive_times.append(time.time())
+        self.jitter_stats.reset()
 
+    def on_packet_received(self, data):
         try:
-            packet_type, packet_data = parse_packet(packet)
+            packet = Packet.from_bytes(data)
         except ValueError:
             return
 
-        if packet_type == PacketType.RESET:
+        if packet.packet_type == Packet.PacketType.RESET:
             logging.info(color('=== Received RESET', 'magenta'))
             self.reset()
             return
 
-        try:
-            packet_flags, packet_index = parse_packet_sequence(packet_data)
-        except ValueError:
-            return
-        interval = (
-            self.receive_times[-1] - self.receive_times[-2]
-            if len(self.receive_times) >= 2
-            else 0
-        )
+        jitter = self.jitter_stats.on_packet_received(packet)
         logging.info(
             color(
-                f'<<< Received packet {packet_index}: '
-                f'flags=0x{packet_flags:02X}, {len(packet)} bytes, '
-                f'interval={interval:.4f}',
+                f'<<< Received packet {packet.sequence}: '
+                f'flags={packet.flags}, {len(data)} bytes, '
+                f'jitter={jitter:.4f}',
                 'green',
             )
         )
 
-        if packet_index != self.expected_packet_index:
+        if packet.sequence != self.expected_packet_index:
             logging.info(
                 color(
                     f'!!! Unexpected packet, expected {self.expected_packet_index} '
-                    f'but received {packet_index}'
+                    f'but received {packet.sequence}'
                 )
             )
 
-        self.expected_packet_index = packet_index + 1
+        self.expected_packet_index = packet.sequence + 1
 
         AsyncRunner.spawn(
             self.packet_io.send_packet(
-                struct.pack('>bbI', PacketType.ACK, packet_flags, packet_index)
+                bytes(Packet(Packet.PacketType.ACK, packet.flags, packet.sequence))
             )
         )
 
-        if packet_flags & PACKET_FLAG_LAST:
-            if len(self.receive_times) >= 3:
-                # Show basic stats
-                intervals = [
-                    self.receive_times[i + 1] - self.receive_times[i]
-                    for i in range(len(self.receive_times) - 1)
-                ]
-                log_stats('Packet intervals', intervals, 3)
-
-                # Show a histogram
-                bin_count = 20
-                bins = [0] * bin_count
-                interval_min = min(intervals)
-                interval_max = max(intervals)
-                interval_range = interval_max - interval_min
-                bin_thresholds = [
-                    interval_min + i * (interval_range / bin_count)
-                    for i in range(bin_count)
-                ]
-                for interval in intervals:
-                    for i in reversed(range(bin_count)):
-                        if interval >= bin_thresholds[i]:
-                            bins[i] += 1
-                            break
-                for i in range(bin_count):
-                    logging.info(f'@@@ >= {bin_thresholds[i]:.4f}: {bins[i]}')
+        if packet.flags & Packet.PacketFlags.LAST:
+            self.jitter_stats.show_stats()
 
             if not self.linger:
                 self.done.set()
@@ -1471,7 +1548,7 @@ def create_mode_factory(ctx, default_mode):
 def create_scenario_factory(ctx, default_scenario):
     scenario = ctx.obj['scenario']
     if scenario is None:
-        scenarion = default_scenario
+        scenario = default_scenario
 
     def create_scenario(packet_io):
         if scenario == 'send':
@@ -1530,6 +1607,7 @@ def create_scenario_factory(ctx, default_scenario):
     '--att-mtu',
     metavar='MTU',
     type=click.IntRange(23, 517),
+    default=517,
     help='GATT MTU (gatt-client mode)',
 )
 @click.option(
@@ -1605,7 +1683,7 @@ def create_scenario_factory(ctx, default_scenario):
     '--packet-size',
     '-s',
     metavar='SIZE',
-    type=click.IntRange(8, 8192),
+    type=click.IntRange(10, 8192),
     default=500,
     help='Packet size (send or ping scenario)',
 )

apps/device_info.py

@@ -29,7 +29,9 @@ from bumble.gatt import Service
 from bumble.profiles.device_information_service import DeviceInformationServiceProxy
 from bumble.profiles.battery_service import BatteryServiceProxy
 from bumble.profiles.gap import GenericAccessServiceProxy
+from bumble.profiles.pacs import PublishedAudioCapabilitiesServiceProxy
 from bumble.profiles.tmap import TelephonyAndMediaAudioServiceProxy
+from bumble.profiles.vcs import VolumeControlServiceProxy
 from bumble.transport import open_transport_or_link
 
 
@@ -126,14 +128,52 @@ async def show_tmas(
     print(color('### Telephony And Media Audio Service', 'yellow'))
 
     if tmas.role:
-        print(
-            color('  Role:', 'green'),
-            await tmas.role.read_value(),
-        )
+        role = await tmas.role.read_value()
+        print(color('  Role:', 'green'), role)
 
     print()
 
 
+# -----------------------------------------------------------------------------
+async def show_pacs(pacs: PublishedAudioCapabilitiesServiceProxy) -> None:
+    print(color('### Published Audio Capabilities Service', 'yellow'))
+
+    contexts = await pacs.available_audio_contexts.read_value()
+    print(color('  Available Audio Contexts:', 'green'), contexts)
+
+    contexts = await pacs.supported_audio_contexts.read_value()
+    print(color('  Supported Audio Contexts:', 'green'), contexts)
+
+    if pacs.sink_pac:
+        pac = await pacs.sink_pac.read_value()
+        print(color('  Sink PAC:                ', 'green'), pac)
+
+    if pacs.sink_audio_locations:
+        audio_locations = await pacs.sink_audio_locations.read_value()
+        print(color('  Sink Audio Locations:    ', 'green'), audio_locations)
+
+    if pacs.source_pac:
+        pac = await pacs.source_pac.read_value()
+        print(color('  Source PAC:              ', 'green'), pac)
+
+    if pacs.source_audio_locations:
+        audio_locations = await pacs.source_audio_locations.read_value()
+        print(color('  Source Audio Locations:  ', 'green'), audio_locations)
+
+    print()
+
+
+# -----------------------------------------------------------------------------
+async def show_vcs(vcs: VolumeControlServiceProxy) -> None:
+    print(color('### Volume Control Service', 'yellow'))
+
+    volume_state = await vcs.volume_state.read_value()
+    print(color('  Volume State:', 'green'), volume_state)
+
+    volume_flags = await vcs.volume_flags.read_value()
+    print(color('  Volume Flags:', 'green'), volume_flags)
+
+
 # -----------------------------------------------------------------------------
 async def show_device_info(peer, done: Optional[asyncio.Future]) -> None:
     try:
@@ -161,6 +201,12 @@ async def show_device_info(peer, done: Optional[asyncio.Future]) -> None:
         if tmas := peer.create_service_proxy(TelephonyAndMediaAudioServiceProxy):
             await try_show(show_tmas, tmas)
 
+        if pacs := peer.create_service_proxy(PublishedAudioCapabilitiesServiceProxy):
+            await try_show(show_pacs, pacs)
+
+        if vcs := peer.create_service_proxy(VolumeControlServiceProxy):
+            await try_show(show_vcs, vcs)
+
         if done is not None:
             done.set_result(None)
     except asyncio.CancelledError:

apps/gg_bridge.py

@@ -234,7 +234,7 @@ class GattlinkNodeBridge(GattlinkL2capEndpoint, Device.Listener):
             Characteristic.WRITEABLE,
             CharacteristicValue(write=self.on_rx_write),
         )
-        self.tx_characteristic = Characteristic(
+        self.tx_characteristic: Characteristic[bytes] = Characteristic(
             GG_GATTLINK_TX_CHARACTERISTIC_UUID,
             Characteristic.Properties.NOTIFY,
             Characteristic.READABLE,

bumble/att.py

@@ -29,13 +29,14 @@ import functools
 import inspect
 import struct
 from typing import (
-    Any,
     Awaitable,
     Callable,
+    Generic,
     Dict,
     List,
     Optional,
     Type,
+    TypeVar,
     Union,
     TYPE_CHECKING,
 )
@@ -43,13 +44,18 @@ from typing import (
 from pyee import EventEmitter
 
 from bumble import utils
-from bumble.core import UUID, name_or_number, ProtocolError
+from bumble.core import UUID, name_or_number, InvalidOperationError, ProtocolError
 from bumble.hci import HCI_Object, key_with_value
 from bumble.colors import color
 
+# -----------------------------------------------------------------------------
+# Typing
+# -----------------------------------------------------------------------------
 if TYPE_CHECKING:
     from bumble.device import Connection
 
+_T = TypeVar('_T')
+
 # -----------------------------------------------------------------------------
 # Constants
 # -----------------------------------------------------------------------------
@@ -748,7 +754,7 @@ class ATT_Handle_Value_Confirmation(ATT_PDU):
 
 
 # -----------------------------------------------------------------------------
-class AttributeValue:
+class AttributeValue(Generic[_T]):
     '''
     Attribute value where reading and/or writing is delegated to functions
     passed as arguments to the constructor.
@@ -757,33 +763,34 @@ class AttributeValue:
     def __init__(
         self,
         read: Union[
-            Callable[[Optional[Connection]], Any],
-            Callable[[Optional[Connection]], Awaitable[Any]],
+            Callable[[Optional[Connection]], _T],
+            Callable[[Optional[Connection]], Awaitable[_T]],
             None,
         ] = None,
         write: Union[
-            Callable[[Optional[Connection], Any], None],
-            Callable[[Optional[Connection], Any], Awaitable[None]],
+            Callable[[Optional[Connection], _T], None],
+            Callable[[Optional[Connection], _T], Awaitable[None]],
             None,
         ] = None,
     ):
         self._read = read
         self._write = write
 
-    def read(self, connection: Optional[Connection]) -> Union[bytes, Awaitable[bytes]]:
-        return self._read(connection) if self._read else b''
+    def read(self, connection: Optional[Connection]) -> Union[_T, Awaitable[_T]]:
+        if self._read is None:
+            raise InvalidOperationError('AttributeValue has no read function')
+        return self._read(connection)
 
     def write(
-        self, connection: Optional[Connection], value: bytes
+        self, connection: Optional[Connection], value: _T
     ) -> Union[Awaitable[None], None]:
-        if self._write:
-            return self._write(connection, value)
-
-        return None
+        if self._write is None:
+            raise InvalidOperationError('AttributeValue has no write function')
+        return self._write(connection, value)
 
 
 # -----------------------------------------------------------------------------
-class Attribute(EventEmitter):
+class Attribute(EventEmitter, Generic[_T]):
     class Permissions(enum.IntFlag):
         READABLE = 0x01
         WRITEABLE = 0x02
@@ -822,13 +829,13 @@ class Attribute(EventEmitter):
     READ_REQUIRES_AUTHORIZATION = Permissions.READ_REQUIRES_AUTHORIZATION
     WRITE_REQUIRES_AUTHORIZATION = Permissions.WRITE_REQUIRES_AUTHORIZATION
 
-    value: Any
+    value: Union[AttributeValue[_T], _T, None]
 
     def __init__(
         self,
         attribute_type: Union[str, bytes, UUID],
         permissions: Union[str, Attribute.Permissions],
-        value: Any = b'',
+        value: Union[AttributeValue[_T], _T, None] = None,
     ) -> None:
         EventEmitter.__init__(self)
         self.handle = 0
@@ -848,11 +855,11 @@ class Attribute(EventEmitter):
 
         self.value = value
 
-    def encode_value(self, value: Any) -> bytes:
-        return value
+    def encode_value(self, value: _T) -> bytes:
+        return value  # type: ignore
 
-    def decode_value(self, value_bytes: bytes) -> Any:
-        return value_bytes
+    def decode_value(self, value: bytes) -> _T:
+        return value  # type: ignore
 
     async def read_value(self, connection: Optional[Connection]) -> bytes:
         if (
@@ -877,11 +884,14 @@ class Attribute(EventEmitter):
                 error_code=ATT_INSUFFICIENT_AUTHORIZATION_ERROR, att_handle=self.handle
             )
 
-        if hasattr(self.value, 'read'):
+        value: Union[_T, None]
+        if isinstance(self.value, AttributeValue):
             try:
-                value = self.value.read(connection)
-                if inspect.isawaitable(value):
-                    value = await value
+                read_value = self.value.read(connection)
+                if inspect.isawaitable(read_value):
+                    value = await read_value
+                else:
+                    value = read_value
             except ATT_Error as error:
                 raise ATT_Error(
                     error_code=error.error_code, att_handle=self.handle
@@ -889,20 +899,24 @@ class Attribute(EventEmitter):
         else:
             value = self.value
 
-        self.emit('read', connection, value)
+        self.emit('read', connection, b'' if value is None else value)
 
-        return self.encode_value(value)
+        return b'' if value is None else self.encode_value(value)
 
-    async def write_value(self, connection: Connection, value_bytes: bytes) -> None:
+    async def write_value(self, connection: Optional[Connection], value: bytes) -> None:
         if (
-            self.permissions & self.WRITE_REQUIRES_ENCRYPTION
-        ) and not connection.encryption:
+            (self.permissions & self.WRITE_REQUIRES_ENCRYPTION)
+            and connection is not None
+            and not connection.encryption
+        ):
             raise ATT_Error(
                 error_code=ATT_INSUFFICIENT_ENCRYPTION_ERROR, att_handle=self.handle
             )
         if (
-            self.permissions & self.WRITE_REQUIRES_AUTHENTICATION
-        ) and not connection.authenticated:
+            (self.permissions & self.WRITE_REQUIRES_AUTHENTICATION)
+            and connection is not None
+            and not connection.authenticated
+        ):
             raise ATT_Error(
                 error_code=ATT_INSUFFICIENT_AUTHENTICATION_ERROR, att_handle=self.handle
             )
@@ -912,11 +926,11 @@ class Attribute(EventEmitter):
                 error_code=ATT_INSUFFICIENT_AUTHORIZATION_ERROR, att_handle=self.handle
             )
 
-        value = self.decode_value(value_bytes)
+        decoded_value = self.decode_value(value)
 
-        if hasattr(self.value, 'write'):
+        if isinstance(self.value, AttributeValue):
             try:
-                result = self.value.write(connection, value)
+                result = self.value.write(connection, decoded_value)
                 if inspect.isawaitable(result):
                     await result
             except ATT_Error as error:
@@ -924,9 +938,9 @@ class Attribute(EventEmitter):
                     error_code=error.error_code, att_handle=self.handle
                 ) from error
         else:
-            self.value = value
+            self.value = decoded_value
 
-        self.emit('write', connection, value)
+        self.emit('write', connection, decoded_value)
 
     def __repr__(self):
         if isinstance(self.value, bytes):

bumble/audio/__init__.py

@@ -0,0 +1,17 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------

bumble/audio/io.py

@@ -0,0 +1,553 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+from __future__ import annotations
+
+import asyncio
+import abc
+from concurrent.futures import ThreadPoolExecutor
+import dataclasses
+import enum
+import logging
+import pathlib
+from typing import (
+    AsyncGenerator,
+    BinaryIO,
+    TYPE_CHECKING,
+)
+import sys
+import wave
+
+from bumble.colors import color
+
+if TYPE_CHECKING:
+    import sounddevice  # type: ignore[import-untyped]
+
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+
+# -----------------------------------------------------------------------------
+# Classes
+# -----------------------------------------------------------------------------
+@dataclasses.dataclass
+class PcmFormat:
+    class Endianness(enum.Enum):
+        LITTLE = 0
+        BIG = 1
+
+    class SampleType(enum.Enum):
+        FLOAT32 = 0
+        INT16 = 1
+
+    endianness: Endianness
+    sample_type: SampleType
+    sample_rate: int
+    channels: int
+
+    @classmethod
+    def from_str(cls, format_str: str) -> PcmFormat:
+        endianness = cls.Endianness.LITTLE  # Others not yet supported.
+        sample_type_str, sample_rate_str, channels_str = format_str.split(',')
+        if sample_type_str == 'int16le':
+            sample_type = cls.SampleType.INT16
+        elif sample_type_str == 'float32le':
+            sample_type = cls.SampleType.FLOAT32
+        else:
+            raise ValueError(f'sample type {sample_type_str} not supported')
+        sample_rate = int(sample_rate_str)
+        channels = int(channels_str)
+
+        return cls(endianness, sample_type, sample_rate, channels)
+
+    @property
+    def bytes_per_sample(self) -> int:
+        return 2 if self.sample_type == self.SampleType.INT16 else 4
+
+
+def check_audio_output(output: str) -> bool:
+    if output == 'device' or output.startswith('device:'):
+        try:
+            import sounddevice
+        except ImportError as exc:
+            raise ValueError(
+                'audio output not available (sounddevice python module not installed)'
+            ) from exc
+        except OSError as exc:
+            raise ValueError(
+                'audio output not available '
+                '(sounddevice python module failed to load: '
+                f'{exc})'
+            ) from exc
+
+        if output == 'device':
+            # Default device
+            return True
+
+        # Specific device
+        device = output[7:]
+        if device == '?':
+            print(color('Audio Devices:', 'yellow'))
+            for device_info in [
+                device_info
+                for device_info in sounddevice.query_devices()
+                if device_info['max_output_channels'] > 0
+            ]:
+                device_index = device_info['index']
+                is_default = (
+                    color(' [default]', 'green')
+                    if sounddevice.default.device[1] == device_index
+                    else ''
+                )
+                print(
+                    f'{color(device_index, "cyan")}: {device_info["name"]}{is_default}'
+                )
+            return False
+
+        try:
+            device_info = sounddevice.query_devices(int(device))
+        except sounddevice.PortAudioError as exc:
+            raise ValueError('No such audio device') from exc
+
+        if device_info['max_output_channels'] < 1:
+            raise ValueError(
+                f'Device {device} ({device_info["name"]}) does not have an output'
+            )
+
+    return True
+
+
+async def create_audio_output(output: str) -> AudioOutput:
+    if output == 'stdout':
+        return StreamAudioOutput(sys.stdout.buffer)
+
+    if output == 'device' or output.startswith('device:'):
+        device_name = '' if output == 'device' else output[7:]
+        return SoundDeviceAudioOutput(device_name)
+
+    if output == 'ffplay':
+        return SubprocessAudioOutput(
+            command=(
+                'ffplay -probesize 32 -fflags nobuffer -analyzeduration 0 '
+                '-ar {sample_rate} '
+                '-ch_layout {channel_layout} '
+                '-f f32le pipe:0'
+            )
+        )
+
+    if output.startswith('file:'):
+        return FileAudioOutput(output[5:])
+
+    raise ValueError('unsupported audio output')
+
+
+class AudioOutput(abc.ABC):
+    """Audio output to which PCM samples can be written."""
+
+    async def open(self, pcm_format: PcmFormat) -> None:
+        """Start the output."""
+
+    @abc.abstractmethod
+    def write(self, pcm_samples: bytes) -> None:
+        """Write PCM samples. Must not block."""
+
+    async def aclose(self) -> None:
+        """Close the output."""
+
+
+class ThreadedAudioOutput(AudioOutput):
+    """Base class for AudioOutput classes that may need to call blocking functions.
+
+    The actual writing is performed in a thread, so as to ensure that calling write()
+    does not block the caller.
+    """
+
+    def __init__(self) -> None:
+        self._thread_pool = ThreadPoolExecutor(1)
+        self._pcm_samples: asyncio.Queue[bytes] = asyncio.Queue()
+        self._write_task = asyncio.create_task(self._write_loop())
+
+    async def _write_loop(self) -> None:
+        while True:
+            pcm_samples = await self._pcm_samples.get()
+            await asyncio.get_running_loop().run_in_executor(
+                self._thread_pool, self._write, pcm_samples
+            )
+
+    @abc.abstractmethod
+    def _write(self, pcm_samples: bytes) -> None:
+        """This method does the actual writing and can block."""
+
+    def write(self, pcm_samples: bytes) -> None:
+        self._pcm_samples.put_nowait(pcm_samples)
+
+    def _close(self) -> None:
+        """This method does the actual closing and can block."""
+
+    async def aclose(self) -> None:
+        await asyncio.get_running_loop().run_in_executor(self._thread_pool, self._close)
+        self._write_task.cancel()
+        self._thread_pool.shutdown()
+
+
+class SoundDeviceAudioOutput(ThreadedAudioOutput):
+    def __init__(self, device_name: str) -> None:
+        super().__init__()
+        self._device = int(device_name) if device_name else None
+        self._stream: sounddevice.RawOutputStream | None = None
+
+    async def open(self, pcm_format: PcmFormat) -> None:
+        import sounddevice  # pylint: disable=import-error
+
+        self._stream = sounddevice.RawOutputStream(
+            samplerate=pcm_format.sample_rate,
+            device=self._device,
+            channels=pcm_format.channels,
+            dtype='float32',
+        )
+        self._stream.start()
+
+    def _write(self, pcm_samples: bytes) -> None:
+        if self._stream is None:
+            return
+
+        try:
+            self._stream.write(pcm_samples)
+        except Exception as error:
+            print(f'Sound device error: {error}')
+            raise
+
+    def _close(self):
+        self._stream.stop()
+        self._stream = None
+
+
+class StreamAudioOutput(ThreadedAudioOutput):
+    """AudioOutput where PCM samples are written to a stream that may block."""
+
+    def __init__(self, stream: BinaryIO) -> None:
+        super().__init__()
+        self._stream = stream
+
+    def _write(self, pcm_samples: bytes) -> None:
+        self._stream.write(pcm_samples)
+        self._stream.flush()
+
+
+class FileAudioOutput(StreamAudioOutput):
+    """AudioOutput where PCM samples are written to a file."""
+
+    def __init__(self, filename: str) -> None:
+        self._file = open(filename, "wb")
+        super().__init__(self._file)
+
+    async def shutdown(self):
+        self._file.close()
+        return await super().shutdown()
+
+
+class SubprocessAudioOutput(AudioOutput):
+    """AudioOutput where audio samples are written to a subprocess via stdin."""
+
+    def __init__(self, command: str) -> None:
+        self._command = command
+        self._subprocess: asyncio.subprocess.Process | None
+
+    async def open(self, pcm_format: PcmFormat) -> None:
+        if pcm_format.channels == 1:
+            channel_layout = 'mono'
+        elif pcm_format.channels == 2:
+            channel_layout = 'stereo'
+        else:
+            raise ValueError(f'{pcm_format.channels} channels not supported')
+
+        command = self._command.format(
+            sample_rate=pcm_format.sample_rate, channel_layout=channel_layout
+        )
+        self._subprocess = await asyncio.create_subprocess_shell(
+            command,
+            stdin=asyncio.subprocess.PIPE,
+            stdout=asyncio.subprocess.PIPE,
+            stderr=asyncio.subprocess.PIPE,
+        )
+
+    def write(self, pcm_samples: bytes) -> None:
+        if self._subprocess is None or self._subprocess.stdin is None:
+            return
+
+        self._subprocess.stdin.write(pcm_samples)
+
+    async def aclose(self):
+        if self._subprocess:
+            self._subprocess.terminate()
+
+
+def check_audio_input(input: str) -> bool:
+    if input == 'device' or input.startswith('device:'):
+        try:
+            import sounddevice  # pylint: disable=import-error
+        except ImportError as exc:
+            raise ValueError(
+                'audio input not available (sounddevice python module not installed)'
+            ) from exc
+        except OSError as exc:
+            raise ValueError(
+                'audio input not available '
+                '(sounddevice python module failed to load: '
+                f'{exc})'
+            ) from exc
+
+        if input == 'device':
+            # Default device
+            return True
+
+        # Specific device
+        device = input[7:]
+        if device == '?':
+            print(color('Audio Devices:', 'yellow'))
+            for device_info in [
+                device_info
+                for device_info in sounddevice.query_devices()
+                if device_info['max_input_channels'] > 0
+            ]:
+                device_index = device_info["index"]
+                is_mono = device_info['max_input_channels'] == 1
+                max_channels = color(f'[{"mono" if is_mono else "stereo"}]', 'cyan')
+                is_default = (
+                    color(' [default]', 'green')
+                    if sounddevice.default.device[0] == device_index
+                    else ''
+                )
+                print(
+                    f'{color(device_index, "cyan")}: {device_info["name"]}'
+                    f' {max_channels}{is_default}'
+                )
+            return False
+
+        try:
+            device_info = sounddevice.query_devices(int(device))
+        except sounddevice.PortAudioError as exc:
+            raise ValueError('No such audio device') from exc
+
+        if device_info['max_input_channels'] < 1:
+            raise ValueError(
+                f'Device {device} ({device_info["name"]}) does not have an input'
+            )
+
+    return True
+
+
+async def create_audio_input(input: str, input_format: str) -> AudioInput:
+    pcm_format: PcmFormat | None
+    if input_format == 'auto':
+        pcm_format = None
+    else:
+        pcm_format = PcmFormat.from_str(input_format)
+
+    if input == 'stdin':
+        if not pcm_format:
+            raise ValueError('input format details required for stdin')
+        return StreamAudioInput(sys.stdin.buffer, pcm_format)
+
+    if input == 'device' or input.startswith('device:'):
+        if not pcm_format:
+            raise ValueError('input format details required for device')
+        device_name = '' if input == 'device' else input[7:]
+        return SoundDeviceAudioInput(device_name, pcm_format)
+
+    # If there's no file: prefix, check if we can assume it is a file.
+    if pathlib.Path(input).is_file():
+        input = 'file:' + input
+
+    if input.startswith('file:'):
+        filename = input[5:]
+        if filename.endswith('.wav'):
+            if input_format != 'auto':
+                raise ValueError(".wav file only supported with 'auto' format")
+            return WaveAudioInput(filename)
+
+        if pcm_format is None:
+            raise ValueError('input format details required for raw PCM files')
+        return FileAudioInput(filename, pcm_format)
+
+    raise ValueError('input not supported')
+
+
+class AudioInput(abc.ABC):
+    """Audio input that produces PCM samples."""
+
+    @abc.abstractmethod
+    async def open(self) -> PcmFormat:
+        """Open the input."""
+
+    @abc.abstractmethod
+    def frames(self, frame_size: int) -> AsyncGenerator[bytes]:
+        """Generate one frame of PCM samples. Must not block."""
+
+    async def aclose(self) -> None:
+        """Close the input."""
+
+
+class ThreadedAudioInput(AudioInput):
+    """Base class for AudioInput implementation where reading samples may block."""
+
+    def __init__(self) -> None:
+        self._thread_pool = ThreadPoolExecutor(1)
+        self._pcm_samples: asyncio.Queue[bytes] = asyncio.Queue()
+
+    @abc.abstractmethod
+    def _read(self, frame_size: int) -> bytes:
+        pass
+
+    @abc.abstractmethod
+    def _open(self) -> PcmFormat:
+        pass
+
+    def _close(self) -> None:
+        pass
+
+    async def open(self) -> PcmFormat:
+        return await asyncio.get_running_loop().run_in_executor(
+            self._thread_pool, self._open
+        )
+
+    async def frames(self, frame_size: int) -> AsyncGenerator[bytes]:
+        while pcm_sample := await asyncio.get_running_loop().run_in_executor(
+            self._thread_pool, self._read, frame_size
+        ):
+            yield pcm_sample
+
+    async def aclose(self) -> None:
+        await asyncio.get_running_loop().run_in_executor(self._thread_pool, self._close)
+        self._thread_pool.shutdown()
+
+
+class WaveAudioInput(ThreadedAudioInput):
+    """Audio input that reads PCM samples from a .wav file."""
+
+    def __init__(self, filename: str) -> None:
+        super().__init__()
+        self._filename = filename
+        self._wav: wave.Wave_read | None = None
+        self._bytes_read = 0
+
+    def _open(self) -> PcmFormat:
+        self._wav = wave.open(self._filename, 'rb')
+        if self._wav.getsampwidth() != 2:
+            raise ValueError('sample width not supported')
+        return PcmFormat(
+            PcmFormat.Endianness.LITTLE,
+            PcmFormat.SampleType.INT16,
+            self._wav.getframerate(),
+            self._wav.getnchannels(),
+        )
+
+    def _read(self, frame_size: int) -> bytes:
+        if not self._wav:
+            return b''
+
+        pcm_samples = self._wav.readframes(frame_size)
+        if not pcm_samples and self._bytes_read:
+            # Loop around.
+            self._wav.rewind()
+            self._bytes_read = 0
+            pcm_samples = self._wav.readframes(frame_size)
+
+        self._bytes_read += len(pcm_samples)
+        return pcm_samples
+
+    def _close(self) -> None:
+        if self._wav:
+            self._wav.close()
+
+
+class StreamAudioInput(ThreadedAudioInput):
+    """AudioInput where samples are read from a raw PCM stream that may block."""
+
+    def __init__(self, stream: BinaryIO, pcm_format: PcmFormat) -> None:
+        super().__init__()
+        self._stream = stream
+        self._pcm_format = pcm_format
+
+    def _open(self) -> PcmFormat:
+        return self._pcm_format
+
+    def _read(self, frame_size: int) -> bytes:
+        return self._stream.read(
+            frame_size * self._pcm_format.channels * self._pcm_format.bytes_per_sample
+        )
+
+
+class FileAudioInput(StreamAudioInput):
+    """AudioInput where PCM samples are read from a raw PCM file."""
+
+    def __init__(self, filename: str, pcm_format: PcmFormat) -> None:
+        self._stream = open(filename, "rb")
+        super().__init__(self._stream, pcm_format)
+
+    def _close(self) -> None:
+        self._stream.close()
+
+
+class SoundDeviceAudioInput(ThreadedAudioInput):
+    def __init__(self, device_name: str, pcm_format: PcmFormat) -> None:
+        super().__init__()
+        self._device = int(device_name) if device_name else None
+        self._pcm_format = pcm_format
+        self._stream: sounddevice.RawInputStream | None = None
+
+    def _open(self) -> PcmFormat:
+        import sounddevice  # pylint: disable=import-error
+
+        self._stream = sounddevice.RawInputStream(
+            samplerate=self._pcm_format.sample_rate,
+            device=self._device,
+            channels=self._pcm_format.channels,
+            dtype='int16',
+        )
+        self._stream.start()
+
+        return PcmFormat(
+            PcmFormat.Endianness.LITTLE,
+            PcmFormat.SampleType.INT16,
+            self._pcm_format.sample_rate,
+            2,
+        )
+
+    def _read(self, frame_size: int) -> bytes:
+        if not self._stream:
+            return b''
+        pcm_buffer, overflowed = self._stream.read(frame_size)
+        if overflowed:
+            logger.warning("input overflow")
+
+        # Convert the buffer to stereo if needed
+        if self._pcm_format.channels == 1:
+            stereo_buffer = bytearray()
+            for i in range(frame_size):
+                sample = pcm_buffer[i * 2 : i * 2 + 2]
+                stereo_buffer += sample + sample
+            return stereo_buffer
+
+        return bytes(pcm_buffer)
+
+    def _close(self):
+        self._stream.stop()
+        self._stream = None

bumble/device.py

@@ -17,6 +17,7 @@
 # -----------------------------------------------------------------------------
 from __future__ import annotations
 import asyncio
+import collections
 from collections.abc import Iterable, Sequence
 from contextlib import (
     asynccontextmanager,
@@ -36,6 +37,7 @@ from typing import (
     Any,
     Callable,
     ClassVar,
+    Deque,
     Dict,
     Optional,
     Type,
@@ -51,7 +53,7 @@ from pyee import EventEmitter
 
 from .colors import color
 from .att import ATT_CID, ATT_DEFAULT_MTU, ATT_PDU
-from .gatt import Characteristic, Descriptor, Service
+from .gatt import Attribute, Characteristic, Descriptor, Service
 from .host import DataPacketQueue, Host
 from .profiles.gap import GenericAccessService
 from .core import (
@@ -1506,6 +1508,49 @@ class BisLink(_IsoLink):
         self.device = self.big.device
 
 
+# -----------------------------------------------------------------------------
+class IsoPacketStream:
+    """Async stream that can write SDUs to a CIS or BIS, with a maximum queue size."""
+
+    iso_link: _IsoLink
+    data_packet_queue: DataPacketQueue
+
+    def __init__(self, iso_link: _IsoLink, max_queue_size: int) -> None:
+        if iso_link.data_packet_queue is None:
+            raise ValueError('link has no data packet queue')
+
+        self.iso_link = iso_link
+        self.data_packet_queue = iso_link.data_packet_queue
+        self.data_packet_queue.on('flow', self._on_flow)
+        self._thresholds: Deque[int] = collections.deque()
+        self._semaphore = asyncio.Semaphore(max_queue_size)
+
+    def _on_flow(self) -> None:
+        # Release the semaphore once for each completed packet.
+        while (
+            self._thresholds and self.data_packet_queue.completed >= self._thresholds[0]
+        ):
+            self._thresholds.popleft()
+            self._semaphore.release()
+
+    async def write(self, sdu: bytes) -> None:
+        """
+        Write an SDU to the queue.
+
+        This method blocks until there are fewer than max_queue_size packets queued
+        but not yet completed.
+        """
+
+        # Wait until there's space in the queue.
+        await self._semaphore.acquire()
+
+        # Queue the packet.
+        self.iso_link.write(sdu)
+
+        # Remember the position of the packet so we can know when it is completed.
+        self._thresholds.append(self.data_packet_queue.queued)
+
+
 # -----------------------------------------------------------------------------
 class Connection(CompositeEventEmitter):
     device: Device
@@ -2176,7 +2221,7 @@ class Device(CompositeEventEmitter):
                         permissions=descriptor["permissions"],
                     )
                     descriptors.append(new_descriptor)
-                new_characteristic = Characteristic(
+                new_characteristic: Characteristic[bytes] = Characteristic(
                     uuid=characteristic["uuid"],
                     properties=Characteristic.Properties.from_string(
                         characteristic["properties"]
@@ -2475,7 +2520,7 @@ class Device(CompositeEventEmitter):
             if self.random_address != hci.Address.ANY_RANDOM:
                 logger.debug(
                     color(
-                        f'LE Random hci.Address: {self.random_address}',
+                        f'LE Random Address: {self.random_address}',
                         'yellow',
                     )
                 )
@@ -4875,16 +4920,84 @@ class Device(CompositeEventEmitter):
             self.gatt_service = gatt_service.GenericAttributeProfileService()
             self.gatt_server.add_service(self.gatt_service)
 
-    async def notify_subscriber(self, connection, attribute, value=None, force=False):
+    async def notify_subscriber(
+        self,
+        connection: Connection,
+        attribute: Attribute,
+        value: Optional[Any] = None,
+        force: bool = False,
+    ) -> None:
+        """
+        Send a notification to an attribute subscriber.
+
+        Args:
+           connection:
+             The connection of the subscriber.
+           attribute:
+             The attribute whose value is notified.
+           value:
+             The value of the attribute (if None, the value is read from the attribute)
+            force:
+              If True, send a notification even if there is no subscriber.
+        """
         await self.gatt_server.notify_subscriber(connection, attribute, value, force)
 
-    async def notify_subscribers(self, attribute, value=None, force=False):
+    async def notify_subscribers(
+        self, attribute: Attribute, value=None, force=False
+    ) -> None:
+        """
+        Send a notification to all the subscribers of an attribute.
+
+        Args:
+           attribute:
+             The attribute whose value is notified.
+           value:
+             The value of the attribute (if None, the value is read from the attribute)
+            force:
+              If True, send a notification for every connection even if there is no
+              subscriber.
+        """
         await self.gatt_server.notify_subscribers(attribute, value, force)
 
-    async def indicate_subscriber(self, connection, attribute, value=None, force=False):
+    async def indicate_subscriber(
+        self,
+        connection: Connection,
+        attribute: Attribute,
+        value: Optional[Any] = None,
+        force: bool = False,
+    ):
+        """
+        Send an indication to an attribute subscriber.
+
+        This method returns when the response to the indication has been received.
+
+        Args:
+           connection:
+             The connection of the subscriber.
+           attribute:
+             The attribute whose value is indicated.
+           value:
+             The value of the attribute (if None, the value is read from the attribute)
+            force:
+              If True, send an indication even if there is no subscriber.
+        """
         await self.gatt_server.indicate_subscriber(connection, attribute, value, force)
 
-    async def indicate_subscribers(self, attribute, value=None, force=False):
+    async def indicate_subscribers(
+        self, attribute: Attribute, value: Optional[Any] = None, force: bool = False
+    ):
+        """
+        Send an indication to all the subscribers of an attribute.
+
+        Args:
+           attribute:
+             The attribute whose value is notified.
+           value:
+             The value of the attribute (if None, the value is read from the attribute)
+            force:
+              If True, send an indication for every connection even if there is no
+              subscriber.
+        """
         await self.gatt_server.indicate_subscribers(attribute, value, force)
 
     @host_event_handler

bumble/gatt.py

@@ -27,28 +27,16 @@ import enum
 import functools
 import logging
 import struct
-from typing import (
-    Any,
-    Callable,
-    Dict,
-    Iterable,
-    List,
-    Optional,
-    Sequence,
-    SupportsBytes,
-    Type,
-    Union,
-    TYPE_CHECKING,
-)
+from typing import Iterable, List, Optional, Sequence, TypeVar, Union
 
 from bumble.colors import color
 from bumble.core import BaseBumbleError, UUID
 from bumble.att import Attribute, AttributeValue
-from bumble.utils import ByteSerializable
-
-if TYPE_CHECKING:
-    from bumble.gatt_client import AttributeProxy
 
+# -----------------------------------------------------------------------------
+# Typing
+# -----------------------------------------------------------------------------
+_T = TypeVar('_T')
 
 # -----------------------------------------------------------------------------
 # Logging
@@ -314,6 +302,7 @@ GATT_CENTRAL_ADDRESS_RESOLUTION__CHARACTERISTIC                = UUID.from_16_bi
 GATT_CLIENT_SUPPORTED_FEATURES_CHARACTERISTIC                  = UUID.from_16_bits(0x2B29, 'Client Supported Features')
 GATT_DATABASE_HASH_CHARACTERISTIC                              = UUID.from_16_bits(0x2B2A, 'Database Hash')
 GATT_SERVER_SUPPORTED_FEATURES_CHARACTERISTIC                  = UUID.from_16_bits(0x2B3A, 'Server Supported Features')
+GATT_LE_GATT_SECURITY_LEVELS_CHARACTERISTIC                    = UUID.from_16_bits(0x2BF5, 'E GATT Security Levels')
 
 # fmt: on
 # pylint: enable=line-too-long
@@ -322,8 +311,6 @@ GATT_SERVER_SUPPORTED_FEATURES_CHARACTERISTIC                  = UUID.from_16_bi
 # -----------------------------------------------------------------------------
 # Utils
 # -----------------------------------------------------------------------------
-
-
 def show_services(services: Iterable[Service]) -> None:
     for service in services:
         print(color(str(service), 'cyan'))
@@ -437,7 +424,7 @@ class IncludedServiceDeclaration(Attribute):
 
 
 # -----------------------------------------------------------------------------
-class Characteristic(Attribute):
+class Characteristic(Attribute[_T]):
     '''
     See Vol 3, Part G - 3.3 CHARACTERISTIC DEFINITION
     '''
@@ -500,7 +487,7 @@ class Characteristic(Attribute):
         uuid: Union[str, bytes, UUID],
         properties: Characteristic.Properties,
         permissions: Union[str, Attribute.Permissions],
-        value: Any = b'',
+        value: Union[AttributeValue[_T], _T, None] = None,
         descriptors: Sequence[Descriptor] = (),
     ):
         super().__init__(uuid, permissions, value)
@@ -560,213 +547,10 @@ class CharacteristicDeclaration(Attribute):
 
 
 # -----------------------------------------------------------------------------
-class CharacteristicValue(AttributeValue):
+class CharacteristicValue(AttributeValue[_T]):
     """Same as AttributeValue, for backward compatibility"""
 
 
-# -----------------------------------------------------------------------------
-class CharacteristicAdapter:
-    '''
-    An adapter that can adapt Characteristic and AttributeProxy objects
-    by wrapping their `read_value()` and `write_value()` methods with ones that
-    return/accept encoded/decoded values.
-
-    For proxies (i.e used by a GATT client), the adaptation is one where the return
-    value of `read_value()` is decoded and the value passed to `write_value()` is
-    encoded. The `subscribe()` method, is wrapped with one where the values are decoded
-    before being passed to the subscriber.
-
-    For local values (i.e hosted by a GATT server) the adaptation is one where the
-    return value of `read_value()` is encoded and the value passed to `write_value()`
-    is decoded.
-    '''
-
-    read_value: Callable
-    write_value: Callable
-
-    def __init__(self, characteristic: Union[Characteristic, AttributeProxy]):
-        self.wrapped_characteristic = characteristic
-        self.subscribers: Dict[Callable, Callable] = (
-            {}
-        )  # Map from subscriber to proxy subscriber
-
-        if isinstance(characteristic, Characteristic):
-            self.read_value = self.read_encoded_value
-            self.write_value = self.write_encoded_value
-        else:
-            self.read_value = self.read_decoded_value
-            self.write_value = self.write_decoded_value
-            self.subscribe = self.wrapped_subscribe
-            self.unsubscribe = self.wrapped_unsubscribe
-
-    def __getattr__(self, name):
-        return getattr(self.wrapped_characteristic, name)
-
-    def __setattr__(self, name, value):
-        if name in (
-            'wrapped_characteristic',
-            'subscribers',
-            'read_value',
-            'write_value',
-            'subscribe',
-            'unsubscribe',
-        ):
-            super().__setattr__(name, value)
-        else:
-            setattr(self.wrapped_characteristic, name, value)
-
-    async def read_encoded_value(self, connection):
-        return self.encode_value(
-            await self.wrapped_characteristic.read_value(connection)
-        )
-
-    async def write_encoded_value(self, connection, value):
-        return await self.wrapped_characteristic.write_value(
-            connection, self.decode_value(value)
-        )
-
-    async def read_decoded_value(self):
-        return self.decode_value(await self.wrapped_characteristic.read_value())
-
-    async def write_decoded_value(self, value, with_response=False):
-        return await self.wrapped_characteristic.write_value(
-            self.encode_value(value), with_response
-        )
-
-    def encode_value(self, value):
-        return value
-
-    def decode_value(self, value):
-        return value
-
-    def wrapped_subscribe(self, subscriber=None):
-        if subscriber is not None:
-            if subscriber in self.subscribers:
-                # We already have a proxy subscriber
-                subscriber = self.subscribers[subscriber]
-            else:
-                # Create and register a proxy that will decode the value
-                original_subscriber = subscriber
-
-                def on_change(value):
-                    original_subscriber(self.decode_value(value))
-
-                self.subscribers[subscriber] = on_change
-                subscriber = on_change
-
-        return self.wrapped_characteristic.subscribe(subscriber)
-
-    def wrapped_unsubscribe(self, subscriber=None):
-        if subscriber in self.subscribers:
-            subscriber = self.subscribers.pop(subscriber)
-
-        return self.wrapped_characteristic.unsubscribe(subscriber)
-
-    def __str__(self) -> str:
-        wrapped = str(self.wrapped_characteristic)
-        return f'{self.__class__.__name__}({wrapped})'
-
-
-# -----------------------------------------------------------------------------
-class DelegatedCharacteristicAdapter(CharacteristicAdapter):
-    '''
-    Adapter that converts bytes values using an encode and a decode function.
-    '''
-
-    def __init__(self, characteristic, encode=None, decode=None):
-        super().__init__(characteristic)
-        self.encode = encode
-        self.decode = decode
-
-    def encode_value(self, value):
-        return self.encode(value) if self.encode else value
-
-    def decode_value(self, value):
-        return self.decode(value) if self.decode else value
-
-
-# -----------------------------------------------------------------------------
-class PackedCharacteristicAdapter(CharacteristicAdapter):
-    '''
-    Adapter that packs/unpacks characteristic values according to a standard
-    Python `struct` format.
-    For formats with a single value, the adapted `read_value` and `write_value`
-    methods return/accept single values. For formats with multiple values,
-    they return/accept a tuple with the same number of elements as is required for
-    the format.
-    '''
-
-    def __init__(self, characteristic, pack_format):
-        super().__init__(characteristic)
-        self.struct = struct.Struct(pack_format)
-
-    def pack(self, *values):
-        return self.struct.pack(*values)
-
-    def unpack(self, buffer):
-        return self.struct.unpack(buffer)
-
-    def encode_value(self, value):
-        return self.pack(*value if isinstance(value, tuple) else (value,))
-
-    def decode_value(self, value):
-        unpacked = self.unpack(value)
-        return unpacked[0] if len(unpacked) == 1 else unpacked
-
-
-# -----------------------------------------------------------------------------
-class MappedCharacteristicAdapter(PackedCharacteristicAdapter):
-    '''
-    Adapter that packs/unpacks characteristic values according to a standard
-    Python `struct` format.
-    The adapted `read_value` and `write_value` methods return/accept a dictionary which
-    is packed/unpacked according to format, with the arguments extracted from the
-    dictionary by key, in the same order as they occur in the `keys` parameter.
-    '''
-
-    def __init__(self, characteristic, pack_format, keys):
-        super().__init__(characteristic, pack_format)
-        self.keys = keys
-
-    # pylint: disable=arguments-differ
-    def pack(self, values):
-        return super().pack(*(values[key] for key in self.keys))
-
-    def unpack(self, buffer):
-        return dict(zip(self.keys, super().unpack(buffer)))
-
-
-# -----------------------------------------------------------------------------
-class UTF8CharacteristicAdapter(CharacteristicAdapter):
-    '''
-    Adapter that converts strings to/from bytes using UTF-8 encoding
-    '''
-
-    def encode_value(self, value: str) -> bytes:
-        return value.encode('utf-8')
-
-    def decode_value(self, value: bytes) -> str:
-        return value.decode('utf-8')
-
-
-# -----------------------------------------------------------------------------
-class SerializableCharacteristicAdapter(CharacteristicAdapter):
-    '''
-    Adapter that converts any class to/from bytes using the class'
-    `to_bytes` and `__bytes__` methods, respectively.
-    '''
-
-    def __init__(self, characteristic, cls: Type[ByteSerializable]):
-        super().__init__(characteristic)
-        self.cls = cls
-
-    def encode_value(self, value: SupportsBytes) -> bytes:
-        return bytes(value)
-
-    def decode_value(self, value: bytes) -> Any:
-        return self.cls.from_bytes(value)
-
-
 # -----------------------------------------------------------------------------
 class Descriptor(Attribute):
     '''

bumble/gatt_adapters.py

@@ -0,0 +1,374 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# GATT - Type Adapters
+# -----------------------------------------------------------------------------
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+from __future__ import annotations
+import struct
+from typing import (
+    Any,
+    Callable,
+    Generic,
+    Iterable,
+    Literal,
+    Optional,
+    Type,
+    TypeVar,
+)
+
+from bumble.core import InvalidOperationError
+from bumble.gatt import Characteristic
+from bumble.gatt_client import CharacteristicProxy
+from bumble.utils import ByteSerializable, IntConvertible
+
+
+# -----------------------------------------------------------------------------
+# Typing
+# -----------------------------------------------------------------------------
+_T = TypeVar('_T')
+_T2 = TypeVar('_T2', bound=ByteSerializable)
+_T3 = TypeVar('_T3', bound=IntConvertible)
+
+
+# -----------------------------------------------------------------------------
+class CharacteristicAdapter(Characteristic, Generic[_T]):
+    '''Base class for GATT Characteristic adapters.'''
+
+    def __init__(self, characteristic: Characteristic) -> None:
+        super().__init__(
+            characteristic.uuid,
+            characteristic.properties,
+            characteristic.permissions,
+            characteristic.value,
+            characteristic.descriptors,
+        )
+
+
+# -----------------------------------------------------------------------------
+class CharacteristicProxyAdapter(CharacteristicProxy[_T]):
+    '''Base class for GATT CharacteristicProxy adapters.'''
+
+    def __init__(self, characteristic_proxy: CharacteristicProxy):
+        super().__init__(
+            characteristic_proxy.client,
+            characteristic_proxy.handle,
+            characteristic_proxy.end_group_handle,
+            characteristic_proxy.uuid,
+            characteristic_proxy.properties,
+        )
+
+
+# -----------------------------------------------------------------------------
+class DelegatedCharacteristicAdapter(CharacteristicAdapter[_T]):
+    '''
+    Adapter that converts bytes values using an encode and/or a decode function.
+    '''
+
+    def __init__(
+        self,
+        characteristic: Characteristic,
+        encode: Optional[Callable[[_T], bytes]] = None,
+        decode: Optional[Callable[[bytes], _T]] = None,
+    ):
+        super().__init__(characteristic)
+        self.encode = encode
+        self.decode = decode
+
+    def encode_value(self, value: _T) -> bytes:
+        if self.encode is None:
+            raise InvalidOperationError('delegated adapter does not have an encoder')
+        return self.encode(value)
+
+    def decode_value(self, value: bytes) -> _T:
+        if self.decode is None:
+            raise InvalidOperationError('delegate adapter does not have a decoder')
+        return self.decode(value)
+
+
+# -----------------------------------------------------------------------------
+class DelegatedCharacteristicProxyAdapter(CharacteristicProxyAdapter[_T]):
+    '''
+    Adapter that converts bytes values using an encode and a decode function.
+    '''
+
+    def __init__(
+        self,
+        characteristic_proxy: CharacteristicProxy,
+        encode: Optional[Callable[[_T], bytes]] = None,
+        decode: Optional[Callable[[bytes], _T]] = None,
+    ):
+        super().__init__(characteristic_proxy)
+        self.encode = encode
+        self.decode = decode
+
+    def encode_value(self, value: _T) -> bytes:
+        if self.encode is None:
+            raise InvalidOperationError('delegated adapter does not have an encoder')
+        return self.encode(value)
+
+    def decode_value(self, value: bytes) -> _T:
+        if self.decode is None:
+            raise InvalidOperationError('delegate adapter does not have a decoder')
+        return self.decode(value)
+
+
+# -----------------------------------------------------------------------------
+class PackedCharacteristicAdapter(CharacteristicAdapter):
+    '''
+    Adapter that packs/unpacks characteristic values according to a standard
+    Python `struct` format.
+    For formats with a single value, the adapted `read_value` and `write_value`
+    methods return/accept single values. For formats with multiple values,
+    they return/accept a tuple with the same number of elements as is required for
+    the format.
+    '''
+
+    def __init__(self, characteristic: Characteristic, pack_format: str) -> None:
+        super().__init__(characteristic)
+        self.struct = struct.Struct(pack_format)
+
+    def pack(self, *values) -> bytes:
+        return self.struct.pack(*values)
+
+    def unpack(self, buffer: bytes) -> tuple:
+        return self.struct.unpack(buffer)
+
+    def encode_value(self, value: Any) -> bytes:
+        return self.pack(*value if isinstance(value, tuple) else (value,))
+
+    def decode_value(self, value: bytes) -> Any:
+        unpacked = self.unpack(value)
+        return unpacked[0] if len(unpacked) == 1 else unpacked
+
+
+# -----------------------------------------------------------------------------
+class PackedCharacteristicProxyAdapter(CharacteristicProxyAdapter):
+    '''
+    Adapter that packs/unpacks characteristic values according to a standard
+    Python `struct` format.
+    For formats with a single value, the adapted `read_value` and `write_value`
+    methods return/accept single values. For formats with multiple values,
+    they return/accept a tuple with the same number of elements as is required for
+    the format.
+    '''
+
+    def __init__(self, characteristic_proxy, pack_format):
+        super().__init__(characteristic_proxy)
+        self.struct = struct.Struct(pack_format)
+
+    def pack(self, *values) -> bytes:
+        return self.struct.pack(*values)
+
+    def unpack(self, buffer: bytes) -> tuple:
+        return self.struct.unpack(buffer)
+
+    def encode_value(self, value: Any) -> bytes:
+        return self.pack(*value if isinstance(value, tuple) else (value,))
+
+    def decode_value(self, value: bytes) -> Any:
+        unpacked = self.unpack(value)
+        return unpacked[0] if len(unpacked) == 1 else unpacked
+
+
+# -----------------------------------------------------------------------------
+class MappedCharacteristicAdapter(PackedCharacteristicAdapter):
+    '''
+    Adapter that packs/unpacks characteristic values according to a standard
+    Python `struct` format.
+    The adapted `read_value` and `write_value` methods return/accept a dictionary which
+    is packed/unpacked according to format, with the arguments extracted from the
+    dictionary by key, in the same order as they occur in the `keys` parameter.
+    '''
+
+    def __init__(
+        self, characteristic: Characteristic, pack_format: str, keys: Iterable[str]
+    ) -> None:
+        super().__init__(characteristic, pack_format)
+        self.keys = keys
+
+    # pylint: disable=arguments-differ
+    def pack(self, values) -> bytes:
+        return super().pack(*(values[key] for key in self.keys))
+
+    def unpack(self, buffer: bytes) -> Any:
+        return dict(zip(self.keys, super().unpack(buffer)))
+
+
+# -----------------------------------------------------------------------------
+class MappedCharacteristicProxyAdapter(PackedCharacteristicProxyAdapter):
+    '''
+    Adapter that packs/unpacks characteristic values according to a standard
+    Python `struct` format.
+    The adapted `read_value` and `write_value` methods return/accept a dictionary which
+    is packed/unpacked according to format, with the arguments extracted from the
+    dictionary by key, in the same order as they occur in the `keys` parameter.
+    '''
+
+    def __init__(
+        self,
+        characteristic_proxy: CharacteristicProxy,
+        pack_format: str,
+        keys: Iterable[str],
+    ) -> None:
+        super().__init__(characteristic_proxy, pack_format)
+        self.keys = keys
+
+    # pylint: disable=arguments-differ
+    def pack(self, values) -> bytes:
+        return super().pack(*(values[key] for key in self.keys))
+
+    def unpack(self, buffer: bytes) -> Any:
+        return dict(zip(self.keys, super().unpack(buffer)))
+
+
+# -----------------------------------------------------------------------------
+class UTF8CharacteristicAdapter(CharacteristicAdapter[str]):
+    '''
+    Adapter that converts strings to/from bytes using UTF-8 encoding
+    '''
+
+    def encode_value(self, value: str) -> bytes:
+        return value.encode('utf-8')
+
+    def decode_value(self, value: bytes) -> str:
+        return value.decode('utf-8')
+
+
+# -----------------------------------------------------------------------------
+class UTF8CharacteristicProxyAdapter(CharacteristicProxyAdapter[str]):
+    '''
+    Adapter that converts strings to/from bytes using UTF-8 encoding
+    '''
+
+    def encode_value(self, value: str) -> bytes:
+        return value.encode('utf-8')
+
+    def decode_value(self, value: bytes) -> str:
+        return value.decode('utf-8')
+
+
+# -----------------------------------------------------------------------------
+class SerializableCharacteristicAdapter(CharacteristicAdapter[_T2]):
+    '''
+    Adapter that converts any class to/from bytes using the class'
+    `to_bytes` and `__bytes__` methods, respectively.
+    '''
+
+    def __init__(self, characteristic: Characteristic, cls: Type[_T2]) -> None:
+        super().__init__(characteristic)
+        self.cls = cls
+
+    def encode_value(self, value: _T2) -> bytes:
+        return bytes(value)
+
+    def decode_value(self, value: bytes) -> _T2:
+        return self.cls.from_bytes(value)
+
+
+# -----------------------------------------------------------------------------
+class SerializableCharacteristicProxyAdapter(CharacteristicProxyAdapter[_T2]):
+    '''
+    Adapter that converts any class to/from bytes using the class'
+    `to_bytes` and `__bytes__` methods, respectively.
+    '''
+
+    def __init__(
+        self, characteristic_proxy: CharacteristicProxy, cls: Type[_T2]
+    ) -> None:
+        super().__init__(characteristic_proxy)
+        self.cls = cls
+
+    def encode_value(self, value: _T2) -> bytes:
+        return bytes(value)
+
+    def decode_value(self, value: bytes) -> _T2:
+        return self.cls.from_bytes(value)
+
+
+# -----------------------------------------------------------------------------
+class EnumCharacteristicAdapter(CharacteristicAdapter[_T3]):
+    '''
+    Adapter that converts int-enum-like classes to/from bytes using the class'
+    `int().to_bytes()` and `from_bytes()` methods, respectively.
+    '''
+
+    def __init__(
+        self,
+        characteristic: Characteristic,
+        cls: Type[_T3],
+        length: int,
+        byteorder: Literal['little', 'big'] = 'little',
+    ):
+        """
+        Initialize an instance.
+
+        Params:
+          characteristic: the Characteristic to adapt to/from
+          cls: the class to/from which to convert integer values
+          length: number of bytes used to represent integer values
+          byteorder: byte order of the byte representation of integers.
+        """
+        super().__init__(characteristic)
+        self.cls = cls
+        self.length = length
+        self.byteorder = byteorder
+
+    def encode_value(self, value: _T3) -> bytes:
+        return int(value).to_bytes(self.length, self.byteorder)
+
+    def decode_value(self, value: bytes) -> _T3:
+        int_value = int.from_bytes(value, self.byteorder)
+        return self.cls(int_value)
+
+
+# -----------------------------------------------------------------------------
+class EnumCharacteristicProxyAdapter(CharacteristicProxyAdapter[_T3]):
+    '''
+    Adapter that converts int-enum-like classes to/from bytes using the class'
+    `int().to_bytes()` and `from_bytes()` methods, respectively.
+    '''
+
+    def __init__(
+        self,
+        characteristic_proxy: CharacteristicProxy,
+        cls: Type[_T3],
+        length: int,
+        byteorder: Literal['little', 'big'] = 'little',
+    ):
+        """
+        Initialize an instance.
+
+        Params:
+          characteristic_proxy: the CharacteristicProxy to adapt to/from
+          cls: the class to/from which to convert integer values
+          length: number of bytes used to represent integer values
+          byteorder: byte order of the byte representation of integers.
+        """
+        super().__init__(characteristic_proxy)
+        self.cls = cls
+        self.length = length
+        self.byteorder = byteorder
+
+    def encode_value(self, value: _T3) -> bytes:
+        return int(value).to_bytes(self.length, self.byteorder)
+
+    def decode_value(self, value: bytes) -> _T3:
+        int_value = int.from_bytes(value, self.byteorder)
+        a = self.cls(int_value)
+        return self.cls(int_value)

bumble/gatt_client.py

@@ -29,16 +29,18 @@ import logging
 import struct
 from datetime import datetime
 from typing import (
+    Any,
+    Callable,
+    Dict,
+    Generic,
+    Iterable,
     List,
     Optional,
-    Dict,
-    Tuple,
-    Callable,
-    Union,
-    Any,
-    Iterable,
-    Type,
     Set,
+    Tuple,
+    Union,
+    Type,
+    TypeVar,
     TYPE_CHECKING,
 )
 
@@ -78,12 +80,18 @@ from .gatt import (
     GATT_INCLUDE_ATTRIBUTE_TYPE,
     Characteristic,
     ClientCharacteristicConfigurationBits,
+    InvalidServiceError,
     TemplateService,
 )
 
+# -----------------------------------------------------------------------------
+# Typing
+# -----------------------------------------------------------------------------
 if TYPE_CHECKING:
     from bumble.device import Connection
 
+_T = TypeVar('_T')
+
 # -----------------------------------------------------------------------------
 # Logging
 # -----------------------------------------------------------------------------
@@ -109,7 +117,7 @@ def show_services(services: Iterable[ServiceProxy]) -> None:
 # -----------------------------------------------------------------------------
 # Proxies
 # -----------------------------------------------------------------------------
-class AttributeProxy(EventEmitter):
+class AttributeProxy(EventEmitter, Generic[_T]):
     def __init__(
         self, client: Client, handle: int, end_group_handle: int, attribute_type: UUID
     ) -> None:
@@ -119,21 +127,21 @@ class AttributeProxy(EventEmitter):
         self.end_group_handle = end_group_handle
         self.type = attribute_type
 
-    async def read_value(self, no_long_read: bool = False) -> bytes:
+    async def read_value(self, no_long_read: bool = False) -> _T:
         return self.decode_value(
             await self.client.read_value(self.handle, no_long_read)
         )
 
-    async def write_value(self, value, with_response=False):
+    async def write_value(self, value: _T, with_response=False):
         return await self.client.write_value(
             self.handle, self.encode_value(value), with_response
         )
 
-    def encode_value(self, value: Any) -> bytes:
-        return value
+    def encode_value(self, value: _T) -> bytes:
+        return value  # type: ignore
 
-    def decode_value(self, value_bytes: bytes) -> Any:
-        return value_bytes
+    def decode_value(self, value: bytes) -> _T:
+        return value  # type: ignore
 
     def __str__(self) -> str:
         return f'Attribute(handle=0x{self.handle:04X}, type={self.type})'
@@ -162,29 +170,40 @@ class ServiceProxy(AttributeProxy):
         self.uuid = uuid
         self.characteristics = []
 
-    async def discover_characteristics(self, uuids=()):
+    async def discover_characteristics(self, uuids=()) -> list[CharacteristicProxy]:
         return await self.client.discover_characteristics(uuids, self)
 
-    def get_characteristics_by_uuid(self, uuid):
+    def get_characteristics_by_uuid(self, uuid: UUID) -> list[CharacteristicProxy]:
+        """Get all the characteristics with a specified UUID."""
         return self.client.get_characteristics_by_uuid(uuid, self)
 
+    def get_required_characteristic_by_uuid(self, uuid: UUID) -> CharacteristicProxy:
+        """
+        Get the first characteristic with a specified UUID.
+
+        If no characteristic with that UUID is found, an InvalidServiceError is raised.
+        """
+        if not (characteristics := self.get_characteristics_by_uuid(uuid)):
+            raise InvalidServiceError(f'{uuid} characteristic not found')
+        return characteristics[0]
+
     def __str__(self) -> str:
         return f'Service(handle=0x{self.handle:04X}, uuid={self.uuid})'
 
 
-class CharacteristicProxy(AttributeProxy):
+class CharacteristicProxy(AttributeProxy[_T]):
     properties: Characteristic.Properties
     descriptors: List[DescriptorProxy]
-    subscribers: Dict[Any, Callable[[bytes], Any]]
+    subscribers: Dict[Any, Callable[[_T], Any]]
 
     def __init__(
         self,
-        client,
-        handle,
-        end_group_handle,
-        uuid,
+        client: Client,
+        handle: int,
+        end_group_handle: int,
+        uuid: UUID,
         properties: int,
-    ):
+    ) -> None:
         super().__init__(client, handle, end_group_handle, uuid)
         self.uuid = uuid
         self.properties = Characteristic.Properties(properties)
@@ -192,21 +211,21 @@ class CharacteristicProxy(AttributeProxy):
         self.descriptors_discovered = False
         self.subscribers = {}  # Map from subscriber to proxy subscriber
 
-    def get_descriptor(self, descriptor_type):
+    def get_descriptor(self, descriptor_type: UUID) -> Optional[DescriptorProxy]:
         for descriptor in self.descriptors:
             if descriptor.type == descriptor_type:
                 return descriptor
 
         return None
 
-    async def discover_descriptors(self):
+    async def discover_descriptors(self) -> list[DescriptorProxy]:
         return await self.client.discover_descriptors(self)
 
     async def subscribe(
         self,
-        subscriber: Optional[Callable[[bytes], Any]] = None,
+        subscriber: Optional[Callable[[_T], Any]] = None,
         prefer_notify: bool = True,
-    ):
+    ) -> None:
         if subscriber is not None:
             if subscriber in self.subscribers:
                 # We already have a proxy subscriber
@@ -221,13 +240,13 @@ class CharacteristicProxy(AttributeProxy):
                 self.subscribers[subscriber] = on_change
                 subscriber = on_change
 
-        return await self.client.subscribe(self, subscriber, prefer_notify)
+        await self.client.subscribe(self, subscriber, prefer_notify)
 
-    async def unsubscribe(self, subscriber=None, force=False):
+    async def unsubscribe(self, subscriber=None, force=False) -> None:
         if subscriber in self.subscribers:
             subscriber = self.subscribers.pop(subscriber)
 
-        return await self.client.unsubscribe(self, subscriber, force)
+        await self.client.unsubscribe(self, subscriber, force)
 
     def __str__(self) -> str:
         return (
@@ -238,7 +257,7 @@ class CharacteristicProxy(AttributeProxy):
 
 
 class DescriptorProxy(AttributeProxy):
-    def __init__(self, client, handle, descriptor_type):
+    def __init__(self, client: Client, handle: int, descriptor_type: UUID) -> None:
         super().__init__(client, handle, 0, descriptor_type)
 
     def __str__(self) -> str:
@@ -667,7 +686,7 @@ class Client:
 
                     properties, handle = struct.unpack_from('<BH', attribute_value)
                     characteristic_uuid = UUID.from_bytes(attribute_value[3:])
-                    characteristic = CharacteristicProxy(
+                    characteristic: CharacteristicProxy = CharacteristicProxy(
                         self, handle, 0, characteristic_uuid, properties
                     )
 
@@ -793,7 +812,7 @@ class Client:
                     logger.warning(f'bogus handle value: {attribute_handle}')
                     return []
 
-                attribute = AttributeProxy(
+                attribute: AttributeProxy = AttributeProxy(
                     self, attribute_handle, 0, UUID.from_bytes(attribute_uuid)
                 )
                 attributes.append(attribute)
@@ -806,7 +825,7 @@ class Client:
     async def subscribe(
         self,
         characteristic: CharacteristicProxy,
-        subscriber: Optional[Callable[[bytes], Any]] = None,
+        subscriber: Optional[Callable[[Any], Any]] = None,
         prefer_notify: bool = True,
     ) -> None:
         # If we haven't already discovered the descriptors for this characteristic,
@@ -856,7 +875,7 @@ class Client:
     async def unsubscribe(
         self,
         characteristic: CharacteristicProxy,
-        subscriber: Optional[Callable[[bytes], Any]] = None,
+        subscriber: Optional[Callable[[Any], Any]] = None,
         force: bool = False,
     ) -> None:
         '''

bumble/gatt_server.py

@@ -36,7 +36,6 @@ from typing import (
     Tuple,
     TypeVar,
     Type,
-    Union,
     TYPE_CHECKING,
 )
 from pyee import EventEmitter
@@ -78,7 +77,6 @@ from bumble.gatt import (
     GATT_REQUEST_TIMEOUT,
     GATT_SECONDARY_SERVICE_ATTRIBUTE_TYPE,
     Characteristic,
-    CharacteristicAdapter,
     CharacteristicDeclaration,
     CharacteristicValue,
     IncludedServiceDeclaration,
@@ -469,7 +467,7 @@ class Server(EventEmitter):
             finally:
                 self.pending_confirmations[connection.handle] = None
 
-    async def notify_or_indicate_subscribers(
+    async def _notify_or_indicate_subscribers(
         self,
         indicate: bool,
         attribute: Attribute,
@@ -503,7 +501,9 @@ class Server(EventEmitter):
         value: Optional[bytes] = None,
         force: bool = False,
     ):
-        return await self.notify_or_indicate_subscribers(False, attribute, value, force)
+        return await self._notify_or_indicate_subscribers(
+            False, attribute, value, force
+        )
 
     async def indicate_subscribers(
         self,
@@ -511,7 +511,7 @@ class Server(EventEmitter):
         value: Optional[bytes] = None,
         force: bool = False,
     ):
-        return await self.notify_or_indicate_subscribers(True, attribute, value, force)
+        return await self._notify_or_indicate_subscribers(True, attribute, value, force)
 
     def on_disconnection(self, connection: Connection) -> None:
         if connection.handle in self.subscribers:

bumble/profiles/aics.py

@@ -24,16 +24,13 @@ import struct
 from dataclasses import dataclass
 from typing import Optional
 
-from bumble import gatt
 from bumble.device import Connection
 from bumble.att import ATT_Error
 from bumble.gatt import (
+    Attribute,
     Characteristic,
-    SerializableCharacteristicAdapter,
-    PackedCharacteristicAdapter,
     TemplateService,
     CharacteristicValue,
-    UTF8CharacteristicAdapter,
     GATT_AUDIO_INPUT_CONTROL_SERVICE,
     GATT_AUDIO_INPUT_STATE_CHARACTERISTIC,
     GATT_GAIN_SETTINGS_ATTRIBUTE_CHARACTERISTIC,
@@ -42,6 +39,14 @@ from bumble.gatt import (
     GATT_AUDIO_INPUT_CONTROL_POINT_CHARACTERISTIC,
     GATT_AUDIO_INPUT_DESCRIPTION_CHARACTERISTIC,
 )
+from bumble.gatt_adapters import (
+    CharacteristicProxy,
+    PackedCharacteristicProxyAdapter,
+    SerializableCharacteristicAdapter,
+    SerializableCharacteristicProxyAdapter,
+    UTF8CharacteristicAdapter,
+    UTF8CharacteristicProxyAdapter,
+)
 from bumble.gatt_client import ProfileServiceProxy, ServiceProxy
 from bumble.utils import OpenIntEnum
 
@@ -124,7 +129,7 @@ class AudioInputState:
     mute: Mute = Mute.NOT_MUTED
     gain_mode: GainMode = GainMode.MANUAL
     change_counter: int = 0
-    attribute_value: Optional[CharacteristicValue] = None
+    attribute: Optional[Attribute] = None
 
     def __bytes__(self) -> bytes:
         return bytes(
@@ -151,10 +156,8 @@ class AudioInputState:
         self.change_counter = (self.change_counter + 1) % (CHANGE_COUNTER_MAX_VALUE + 1)
 
     async def notify_subscribers_via_connection(self, connection: Connection) -> None:
-        assert self.attribute_value is not None
-        await connection.device.notify_subscribers(
-            attribute=self.attribute_value, value=bytes(self)
-        )
+        assert self.attribute is not None
+        await connection.device.notify_subscribers(attribute=self.attribute)
 
 
 @dataclass
@@ -315,24 +318,28 @@ class AudioInputDescription:
     '''
 
     audio_input_description: str = "Bluetooth"
-    attribute_value: Optional[CharacteristicValue] = None
+    attribute: Optional[Attribute] = None
 
     def on_read(self, _connection: Optional[Connection]) -> str:
         return self.audio_input_description
 
     async def on_write(self, connection: Optional[Connection], value: str) -> None:
         assert connection
-        assert self.attribute_value
+        assert self.attribute
 
         self.audio_input_description = value
-        await connection.device.notify_subscribers(
-            attribute=self.attribute_value, value=value
-        )
+        await connection.device.notify_subscribers(attribute=self.attribute)
 
 
 class AICSService(TemplateService):
     UUID = GATT_AUDIO_INPUT_CONTROL_SERVICE
 
+    audio_input_state_characteristic: Characteristic[AudioInputState]
+    audio_input_type_characteristic: Characteristic[bytes]
+    audio_input_status_characteristic: Characteristic[bytes]
+    audio_input_control_point_characteristic: Characteristic[bytes]
+    gain_settings_properties_characteristic: Characteristic[GainSettingsProperties]
+
     def __init__(
         self,
         audio_input_state: Optional[AudioInputState] = None,
@@ -374,9 +381,7 @@ class AICSService(TemplateService):
             ),
             AudioInputState,
         )
-        self.audio_input_state.attribute_value = (
-            self.audio_input_state_characteristic.value
-        )
+        self.audio_input_state.attribute = self.audio_input_state_characteristic
 
         self.gain_settings_properties_characteristic = (
             SerializableCharacteristicAdapter(
@@ -425,8 +430,8 @@ class AICSService(TemplateService):
                 ),
             )
         )
-        self.audio_input_description.attribute_value = (
-            self.audio_input_control_point_characteristic.value
+        self.audio_input_description.attribute = (
+            self.audio_input_control_point_characteristic
         )
 
         super().__init__(
@@ -448,57 +453,43 @@ class AICSService(TemplateService):
 class AICSServiceProxy(ProfileServiceProxy):
     SERVICE_CLASS = AICSService
 
+    audio_input_state: CharacteristicProxy[AudioInputState]
+    gain_settings_properties: CharacteristicProxy[GainSettingsProperties]
+    audio_input_status: CharacteristicProxy[int]
+    audio_input_control_point: CharacteristicProxy[bytes]
+
     def __init__(self, service_proxy: ServiceProxy) -> None:
         self.service_proxy = service_proxy
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.audio_input_state = SerializableCharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_AUDIO_INPUT_STATE_CHARACTERISTIC
-            )
-        ):
-            raise gatt.InvalidServiceError("Audio Input State Characteristic not found")
-        self.audio_input_state = SerializableCharacteristicAdapter(
-            characteristics[0], AudioInputState
+            ),
+            AudioInputState,
         )
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.gain_settings_properties = SerializableCharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_GAIN_SETTINGS_ATTRIBUTE_CHARACTERISTIC
-            )
-        ):
-            raise gatt.InvalidServiceError(
-                "Gain Settings Attribute Characteristic not found"
-            )
-        self.gain_settings_properties = SerializableCharacteristicAdapter(
-            characteristics[0], GainSettingsProperties
+            ),
+            GainSettingsProperties,
         )
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.audio_input_status = PackedCharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_AUDIO_INPUT_STATUS_CHARACTERISTIC
-            )
-        ):
-            raise gatt.InvalidServiceError(
-                "Audio Input Status Characteristic not found"
-            )
-        self.audio_input_status = PackedCharacteristicAdapter(characteristics[0], 'B')
+            ),
+            'B',
+        )
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.audio_input_control_point = (
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_AUDIO_INPUT_CONTROL_POINT_CHARACTERISTIC
             )
-        ):
-            raise gatt.InvalidServiceError(
-                "Audio Input Control Point Characteristic not found"
-            )
-        self.audio_input_control_point = characteristics[0]
+        )
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.audio_input_description = UTF8CharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_AUDIO_INPUT_DESCRIPTION_CHARACTERISTIC
             )
-        ):
-            raise gatt.InvalidServiceError(
-                "Audio Input Description Characteristic not found"
-            )
-        self.audio_input_description = UTF8CharacteristicAdapter(characteristics[0])
+        )

bumble/profiles/asha.py

@@ -134,12 +134,14 @@ class AshaService(gatt.TemplateService):
             ),
         )
 
-        self.audio_control_point_characteristic = gatt.Characteristic(
-            gatt.GATT_ASHA_AUDIO_CONTROL_POINT_CHARACTERISTIC,
-            gatt.Characteristic.Properties.WRITE
-            | gatt.Characteristic.Properties.WRITE_WITHOUT_RESPONSE,
-            gatt.Characteristic.WRITEABLE,
-            gatt.CharacteristicValue(write=self._on_audio_control_point_write),
+        self.audio_control_point_characteristic: gatt.Characteristic[bytes] = (
+            gatt.Characteristic(
+                gatt.GATT_ASHA_AUDIO_CONTROL_POINT_CHARACTERISTIC,
+                gatt.Characteristic.Properties.WRITE
+                | gatt.Characteristic.Properties.WRITE_WITHOUT_RESPONSE,
+                gatt.Characteristic.WRITEABLE,
+                gatt.CharacteristicValue(write=self._on_audio_control_point_write),
+            )
         )
         self.audio_status_characteristic = gatt.Characteristic(
             gatt.GATT_ASHA_AUDIO_STATUS_CHARACTERISTIC,
@@ -147,7 +149,7 @@ class AshaService(gatt.TemplateService):
             gatt.Characteristic.READABLE,
             bytes([AudioStatus.OK]),
         )
-        self.volume_characteristic = gatt.Characteristic(
+        self.volume_characteristic: gatt.Characteristic[bytes] = gatt.Characteristic(
             gatt.GATT_ASHA_VOLUME_CHARACTERISTIC,
             gatt.Characteristic.Properties.WRITE_WITHOUT_RESPONSE,
             gatt.Characteristic.WRITEABLE,
@@ -166,13 +168,13 @@ class AshaService(gatt.TemplateService):
             struct.pack('<H', self.psm),
         )
 
-        characteristics = [
+        characteristics = (
             self.read_only_properties_characteristic,
             self.audio_control_point_characteristic,
             self.audio_status_characteristic,
             self.volume_characteristic,
             self.le_psm_out_characteristic,
-        ]
+        )
 
         super().__init__(characteristics)
 
@@ -288,8 +290,8 @@ class AshaServiceProxy(gatt_client.ProfileServiceProxy):
                 'psm_characteristic',
             ),
         ):
-            if not (
-                characteristics := self.service_proxy.get_characteristics_by_uuid(uuid)
-            ):
-                raise gatt.InvalidServiceError(f"Missing {uuid} Characteristic")
-            setattr(self, attribute_name, characteristics[0])
+            setattr(
+                self,
+                attribute_name,
+                self.service_proxy.get_required_characteristic_by_uuid(uuid),
+            )

bumble/profiles/bass.py

@@ -20,11 +20,12 @@ from __future__ import annotations
 import dataclasses
 import logging
 import struct
-from typing import ClassVar, List, Optional, Sequence
+from typing import ClassVar, Optional, Sequence
 
 from bumble import core
 from bumble import device
 from bumble import gatt
+from bumble import gatt_adapters
 from bumble import gatt_client
 from bumble import hci
 from bumble import utils
@@ -52,7 +53,7 @@ def encode_subgroups(subgroups: Sequence[SubgroupInfo]) -> bytes:
     )
 
 
-def decode_subgroups(data: bytes) -> List[SubgroupInfo]:
+def decode_subgroups(data: bytes) -> list[SubgroupInfo]:
     num_subgroups = data[0]
     offset = 1
     subgroups = []
@@ -273,7 +274,7 @@ class BroadcastReceiveState:
     pa_sync_state: PeriodicAdvertisingSyncState
     big_encryption: BigEncryption
     bad_code: bytes
-    subgroups: List[SubgroupInfo]
+    subgroups: list[SubgroupInfo]
 
     @classmethod
     def from_bytes(cls, data: bytes) -> BroadcastReceiveState:
@@ -354,34 +355,27 @@ class BroadcastAudioScanServiceProxy(gatt_client.ProfileServiceProxy):
     SERVICE_CLASS = BroadcastAudioScanService
 
     broadcast_audio_scan_control_point: gatt_client.CharacteristicProxy
-    broadcast_receive_states: List[gatt.SerializableCharacteristicAdapter]
+    broadcast_receive_states: list[
+        gatt_client.CharacteristicProxy[Optional[BroadcastReceiveState]]
+    ]
 
     def __init__(self, service_proxy: gatt_client.ServiceProxy):
         self.service_proxy = service_proxy
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.broadcast_audio_scan_control_point = (
+            service_proxy.get_required_characteristic_by_uuid(
                 gatt.GATT_BROADCAST_AUDIO_SCAN_CONTROL_POINT_CHARACTERISTIC
             )
-        ):
-            raise gatt.InvalidServiceError(
-                "Broadcast Audio Scan Control Point characteristic not found"
-            )
-        self.broadcast_audio_scan_control_point = characteristics[0]
+        )
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.broadcast_receive_states = [
+            gatt_adapters.DelegatedCharacteristicProxyAdapter(
+                characteristic,
+                decode=lambda x: BroadcastReceiveState.from_bytes(x) if x else None,
+            )
+            for characteristic in service_proxy.get_characteristics_by_uuid(
                 gatt.GATT_BROADCAST_RECEIVE_STATE_CHARACTERISTIC
             )
-        ):
-            raise gatt.InvalidServiceError(
-                "Broadcast Receive State characteristic not found"
-            )
-        self.broadcast_receive_states = [
-            gatt.SerializableCharacteristicAdapter(
-                characteristic, BroadcastReceiveState
-            )
-            for characteristic in characteristics
         ]
 
     async def send_control_point_operation(

bumble/profiles/battery_service.py

@@ -16,14 +16,20 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
-from ..gatt_client import ProfileServiceProxy
-from ..gatt import (
+from typing import Optional
+
+from bumble.gatt_client import ProfileServiceProxy
+from bumble.gatt import (
     GATT_BATTERY_SERVICE,
     GATT_BATTERY_LEVEL_CHARACTERISTIC,
     TemplateService,
     Characteristic,
     CharacteristicValue,
+)
+from bumble.gatt_client import CharacteristicProxy
+from bumble.gatt_adapters import (
     PackedCharacteristicAdapter,
+    PackedCharacteristicProxyAdapter,
 )
 
 
@@ -32,6 +38,8 @@ class BatteryService(TemplateService):
     UUID = GATT_BATTERY_SERVICE
     BATTERY_LEVEL_FORMAT = 'B'
 
+    battery_level_characteristic: Characteristic[int]
+
     def __init__(self, read_battery_level):
         self.battery_level_characteristic = PackedCharacteristicAdapter(
             Characteristic(
@@ -49,13 +57,15 @@ class BatteryService(TemplateService):
 class BatteryServiceProxy(ProfileServiceProxy):
     SERVICE_CLASS = BatteryService
 
+    battery_level: Optional[CharacteristicProxy[int]]
+
     def __init__(self, service_proxy):
         self.service_proxy = service_proxy
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             GATT_BATTERY_LEVEL_CHARACTERISTIC
         ):
-            self.battery_level = PackedCharacteristicAdapter(
+            self.battery_level = PackedCharacteristicProxyAdapter(
                 characteristics[0], pack_format=BatteryService.BATTERY_LEVEL_FORMAT
             )
         else:

bumble/profiles/device_information_service.py

@@ -19,7 +19,6 @@
 import struct
 from typing import Optional, Tuple
 
-from bumble.gatt_client import ServiceProxy, ProfileServiceProxy, CharacteristicProxy
 from bumble.gatt import (
     GATT_DEVICE_INFORMATION_SERVICE,
     GATT_FIRMWARE_REVISION_STRING_CHARACTERISTIC,
@@ -32,9 +31,12 @@ from bumble.gatt import (
     GATT_REGULATORY_CERTIFICATION_DATA_LIST_CHARACTERISTIC,
     TemplateService,
     Characteristic,
-    DelegatedCharacteristicAdapter,
-    UTF8CharacteristicAdapter,
 )
+from bumble.gatt_adapters import (
+    DelegatedCharacteristicProxyAdapter,
+    UTF8CharacteristicProxyAdapter,
+)
+from bumble.gatt_client import CharacteristicProxy, ProfileServiceProxy, ServiceProxy
 
 
 # -----------------------------------------------------------------------------
@@ -62,7 +64,7 @@ class DeviceInformationService(TemplateService):
         ieee_regulatory_certification_data_list: Optional[bytes] = None,
         # TODO: pnp_id
     ):
-        characteristics = [
+        characteristics: list[Characteristic[bytes]] = [
             Characteristic(
                 uuid,
                 Characteristic.Properties.READ,
@@ -107,14 +109,14 @@ class DeviceInformationService(TemplateService):
 class DeviceInformationServiceProxy(ProfileServiceProxy):
     SERVICE_CLASS = DeviceInformationService
 
-    manufacturer_name: Optional[UTF8CharacteristicAdapter]
-    model_number: Optional[UTF8CharacteristicAdapter]
-    serial_number: Optional[UTF8CharacteristicAdapter]
-    hardware_revision: Optional[UTF8CharacteristicAdapter]
-    firmware_revision: Optional[UTF8CharacteristicAdapter]
-    software_revision: Optional[UTF8CharacteristicAdapter]
-    system_id: Optional[DelegatedCharacteristicAdapter]
-    ieee_regulatory_certification_data_list: Optional[CharacteristicProxy]
+    manufacturer_name: Optional[CharacteristicProxy[str]]
+    model_number: Optional[CharacteristicProxy[str]]
+    serial_number: Optional[CharacteristicProxy[str]]
+    hardware_revision: Optional[CharacteristicProxy[str]]
+    firmware_revision: Optional[CharacteristicProxy[str]]
+    software_revision: Optional[CharacteristicProxy[str]]
+    system_id: Optional[CharacteristicProxy[tuple[int, int]]]
+    ieee_regulatory_certification_data_list: Optional[CharacteristicProxy[bytes]]
 
     def __init__(self, service_proxy: ServiceProxy):
         self.service_proxy = service_proxy
@@ -128,7 +130,7 @@ class DeviceInformationServiceProxy(ProfileServiceProxy):
             ('software_revision', GATT_SOFTWARE_REVISION_STRING_CHARACTERISTIC),
         ):
             if characteristics := service_proxy.get_characteristics_by_uuid(uuid):
-                characteristic = UTF8CharacteristicAdapter(characteristics[0])
+                characteristic = UTF8CharacteristicProxyAdapter(characteristics[0])
             else:
                 characteristic = None
             self.__setattr__(field, characteristic)
@@ -136,7 +138,7 @@ class DeviceInformationServiceProxy(ProfileServiceProxy):
         if characteristics := service_proxy.get_characteristics_by_uuid(
             GATT_SYSTEM_ID_CHARACTERISTIC
         ):
-            self.system_id = DelegatedCharacteristicAdapter(
+            self.system_id = DelegatedCharacteristicProxyAdapter(
                 characteristics[0],
                 encode=lambda v: DeviceInformationService.pack_system_id(*v),
                 decode=DeviceInformationService.unpack_system_id,

bumble/profiles/gap.py

@@ -25,14 +25,15 @@ from bumble.core import Appearance
 from bumble.gatt import (
     TemplateService,
     Characteristic,
-    CharacteristicAdapter,
-    DelegatedCharacteristicAdapter,
-    UTF8CharacteristicAdapter,
     GATT_GENERIC_ACCESS_SERVICE,
     GATT_DEVICE_NAME_CHARACTERISTIC,
     GATT_APPEARANCE_CHARACTERISTIC,
 )
-from bumble.gatt_client import ProfileServiceProxy, ServiceProxy
+from bumble.gatt_adapters import (
+    DelegatedCharacteristicProxyAdapter,
+    UTF8CharacteristicProxyAdapter,
+)
+from bumble.gatt_client import CharacteristicProxy, ProfileServiceProxy, ServiceProxy
 
 # -----------------------------------------------------------------------------
 # Logging
@@ -49,6 +50,9 @@ logger = logging.getLogger(__name__)
 class GenericAccessService(TemplateService):
     UUID = GATT_GENERIC_ACCESS_SERVICE
 
+    device_name_characteristic: Characteristic[bytes]
+    appearance_characteristic: Characteristic[bytes]
+
     def __init__(
         self, device_name: str, appearance: Union[Appearance, Tuple[int, int], int] = 0
     ):
@@ -84,8 +88,8 @@ class GenericAccessService(TemplateService):
 class GenericAccessServiceProxy(ProfileServiceProxy):
     SERVICE_CLASS = GenericAccessService
 
-    device_name: Optional[CharacteristicAdapter]
-    appearance: Optional[DelegatedCharacteristicAdapter]
+    device_name: Optional[CharacteristicProxy[str]]
+    appearance: Optional[CharacteristicProxy[Appearance]]
 
     def __init__(self, service_proxy: ServiceProxy):
         self.service_proxy = service_proxy
@@ -93,14 +97,14 @@ class GenericAccessServiceProxy(ProfileServiceProxy):
         if characteristics := service_proxy.get_characteristics_by_uuid(
             GATT_DEVICE_NAME_CHARACTERISTIC
         ):
-            self.device_name = UTF8CharacteristicAdapter(characteristics[0])
+            self.device_name = UTF8CharacteristicProxyAdapter(characteristics[0])
         else:
             self.device_name = None
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             GATT_APPEARANCE_CHARACTERISTIC
         ):
-            self.appearance = DelegatedCharacteristicAdapter(
+            self.appearance = DelegatedCharacteristicProxyAdapter(
                 characteristics[0],
                 decode=lambda value: Appearance.from_int(
                     struct.unpack_from('<H', value, 0)[0],

bumble/profiles/gatt_service.py

@@ -110,6 +110,7 @@ class GenericAttributeProfileService(gatt.TemplateService):
             gatt.GATT_CHARACTERISTIC_ATTRIBUTE_TYPE,
             gatt.GATT_CHARACTERISTIC_EXTENDED_PROPERTIES_DESCRIPTOR,
         ):
+            assert isinstance(attribute.value, bytes)
             return (
                 struct.pack("<H", attribute.handle)
                 + attribute.type.to_bytes()

bumble/profiles/gmap.py

@@ -22,7 +22,6 @@ from typing import Optional
 
 from bumble.gatt import (
     TemplateService,
-    DelegatedCharacteristicAdapter,
     Characteristic,
     GATT_GAMING_AUDIO_SERVICE,
     GATT_GMAP_ROLE_CHARACTERISTIC,
@@ -30,9 +29,9 @@ from bumble.gatt import (
     GATT_UGT_FEATURES_CHARACTERISTIC,
     GATT_BGS_FEATURES_CHARACTERISTIC,
     GATT_BGR_FEATURES_CHARACTERISTIC,
-    InvalidServiceError,
 )
-from bumble.gatt_client import ProfileServiceProxy, ServiceProxy
+from bumble.gatt_adapters import DelegatedCharacteristicProxyAdapter
+from bumble.gatt_client import CharacteristicProxy, ProfileServiceProxy, ServiceProxy
 from enum import IntFlag
 
 
@@ -151,48 +150,49 @@ class GamingAudioService(TemplateService):
 class GamingAudioServiceProxy(ProfileServiceProxy):
     SERVICE_CLASS = GamingAudioService
 
+    ugg_features: Optional[CharacteristicProxy[UggFeatures]] = None
+    ugt_features: Optional[CharacteristicProxy[UgtFeatures]] = None
+    bgs_features: Optional[CharacteristicProxy[BgsFeatures]] = None
+    bgr_features: Optional[CharacteristicProxy[BgrFeatures]] = None
+
     def __init__(self, service_proxy: ServiceProxy) -> None:
         self.service_proxy = service_proxy
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.gmap_role = DelegatedCharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_GMAP_ROLE_CHARACTERISTIC
-            )
-        ):
-            raise InvalidServiceError("GMAP Role Characteristic not found")
-        self.gmap_role = DelegatedCharacteristicAdapter(
-            characteristic=characteristics[0],
+            ),
             decode=lambda value: GmapRole(value[0]),
         )
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             GATT_UGG_FEATURES_CHARACTERISTIC
         ):
-            self.ugg_features = DelegatedCharacteristicAdapter(
-                characteristic=characteristics[0],
+            self.ugg_features = DelegatedCharacteristicProxyAdapter(
+                characteristics[0],
                 decode=lambda value: UggFeatures(value[0]),
             )
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             GATT_UGT_FEATURES_CHARACTERISTIC
         ):
-            self.ugt_features = DelegatedCharacteristicAdapter(
-                characteristic=characteristics[0],
+            self.ugt_features = DelegatedCharacteristicProxyAdapter(
+                characteristics[0],
                 decode=lambda value: UgtFeatures(value[0]),
             )
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             GATT_BGS_FEATURES_CHARACTERISTIC
         ):
-            self.bgs_features = DelegatedCharacteristicAdapter(
-                characteristic=characteristics[0],
+            self.bgs_features = DelegatedCharacteristicProxyAdapter(
+                characteristics[0],
                 decode=lambda value: BgsFeatures(value[0]),
             )
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             GATT_BGR_FEATURES_CHARACTERISTIC
         ):
-            self.bgr_features = DelegatedCharacteristicAdapter(
-                characteristic=characteristics[0],
+            self.bgr_features = DelegatedCharacteristicProxyAdapter(
+                characteristics[0],
                 decode=lambda value: BgrFeatures(value[0]),
             )

bumble/profiles/hap.py

@@ -18,14 +18,15 @@
 from __future__ import annotations
 import asyncio
 import functools
-from bumble import att, gatt, gatt_client
+from dataclasses import dataclass, field
+import logging
+from typing import Any, Dict, List, Optional, Set, Union
+
+from bumble import att, gatt, gatt_adapters, gatt_client
 from bumble.core import InvalidArgumentError, InvalidStateError
 from bumble.device import Device, Connection
 from bumble.utils import AsyncRunner, OpenIntEnum
 from bumble.hci import Address
-from dataclasses import dataclass, field
-import logging
-from typing import Any, Dict, List, Optional, Set, Union
 
 
 # -----------------------------------------------------------------------------
@@ -631,11 +632,12 @@ class HearingAccessServiceProxy(gatt_client.ProfileServiceProxy):
 
     hearing_aid_preset_control_point: gatt_client.CharacteristicProxy
     preset_control_point_indications: asyncio.Queue
+    active_preset_index_notification: asyncio.Queue
 
     def __init__(self, service_proxy: gatt_client.ServiceProxy) -> None:
         self.service_proxy = service_proxy
 
-        self.server_features = gatt.PackedCharacteristicAdapter(
+        self.server_features = gatt_adapters.PackedCharacteristicProxyAdapter(
             service_proxy.get_characteristics_by_uuid(
                 gatt.GATT_HEARING_AID_FEATURES_CHARACTERISTIC
             )[0],
@@ -648,7 +650,7 @@ class HearingAccessServiceProxy(gatt_client.ProfileServiceProxy):
             )[0]
         )
 
-        self.active_preset_index = gatt.PackedCharacteristicAdapter(
+        self.active_preset_index = gatt_adapters.PackedCharacteristicProxyAdapter(
             service_proxy.get_characteristics_by_uuid(
                 gatt.GATT_ACTIVE_PRESET_INDEX_CHARACTERISTIC
             )[0],

bumble/profiles/heart_rate_service.py

@@ -16,13 +16,14 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 from enum import IntEnum
 import struct
+from typing import Optional
 
 from bumble import core
-from ..gatt_client import ProfileServiceProxy
-from ..att import ATT_Error
-from ..gatt import (
+from bumble.att import ATT_Error
+from bumble.gatt import (
     GATT_HEART_RATE_SERVICE,
     GATT_HEART_RATE_MEASUREMENT_CHARACTERISTIC,
     GATT_BODY_SENSOR_LOCATION_CHARACTERISTIC,
@@ -30,10 +31,13 @@ from ..gatt import (
     TemplateService,
     Characteristic,
     CharacteristicValue,
-    SerializableCharacteristicAdapter,
+)
+from bumble.gatt_adapters import (
     DelegatedCharacteristicAdapter,
     PackedCharacteristicAdapter,
+    SerializableCharacteristicAdapter,
 )
+from bumble.gatt_client import CharacteristicProxy, ProfileServiceProxy
 
 
 # -----------------------------------------------------------------------------
@@ -43,6 +47,10 @@ class HeartRateService(TemplateService):
     CONTROL_POINT_NOT_SUPPORTED = 0x80
     RESET_ENERGY_EXPENDED = 0x01
 
+    heart_rate_measurement_characteristic: Characteristic[HeartRateMeasurement]
+    body_sensor_location_characteristic: Characteristic[BodySensorLocation]
+    heart_rate_control_point_characteristic: Characteristic[int]
+
     class BodySensorLocation(IntEnum):
         OTHER = 0
         CHEST = 1
@@ -198,6 +206,14 @@ class HeartRateService(TemplateService):
 class HeartRateServiceProxy(ProfileServiceProxy):
     SERVICE_CLASS = HeartRateService
 
+    heart_rate_measurement: Optional[
+        CharacteristicProxy[HeartRateService.HeartRateMeasurement]
+    ]
+    body_sensor_location: Optional[
+        CharacteristicProxy[HeartRateService.BodySensorLocation]
+    ]
+    heart_rate_control_point: Optional[CharacteristicProxy[int]]
+
     def __init__(self, service_proxy):
         self.service_proxy = service_proxy
 

bumble/profiles/le_audio.py

@@ -17,23 +17,35 @@
 # -----------------------------------------------------------------------------
 from __future__ import annotations
 import dataclasses
+import enum
 import struct
-from typing import List, Type
+from typing import Any, List, Type
 from typing_extensions import Self
 
+from bumble.profiles import bap
 from bumble import utils
 
 
 # -----------------------------------------------------------------------------
 # Classes
 # -----------------------------------------------------------------------------
+class AudioActiveState(utils.OpenIntEnum):
+    NO_AUDIO_DATA_TRANSMITTED = 0x00
+    AUDIO_DATA_TRANSMITTED = 0x01
+
+
+class AssistedListeningStream(utils.OpenIntEnum):
+    UNSPECIFIED_AUDIO_ENHANCEMENT = 0x00
+
+
 @dataclasses.dataclass
 class Metadata:
     '''Bluetooth Assigned Numbers, Section 6.12.6 - Metadata LTV structures.
 
-    As Metadata fields may extend, and Spec doesn't forbid duplication, we don't parse
-    Metadata into a key-value style dataclass here. Rather, we encourage users to parse
-    again outside the lib.
+    As Metadata fields may extend, and the spec may not guarantee the uniqueness of
+    tags, we don't automatically parse the Metadata data into specific classes.
+    Users of this class may decode the data by themselves, or use the Entry.decode
+    method.
     '''
 
     class Tag(utils.OpenIntEnum):
@@ -57,6 +69,44 @@ class Metadata:
         tag: Metadata.Tag
         data: bytes
 
+        def decode(self) -> Any:
+            """
+            Decode the data into an object, if possible.
+
+            If no specific object class exists to represent the data, the raw data
+            bytes are returned.
+            """
+
+            if self.tag in (
+                Metadata.Tag.PREFERRED_AUDIO_CONTEXTS,
+                Metadata.Tag.STREAMING_AUDIO_CONTEXTS,
+            ):
+                return bap.ContextType(struct.unpack("<H", self.data)[0])
+
+            if self.tag in (
+                Metadata.Tag.PROGRAM_INFO,
+                Metadata.Tag.PROGRAM_INFO_URI,
+                Metadata.Tag.BROADCAST_NAME,
+            ):
+                return self.data.decode("utf-8")
+
+            if self.tag == Metadata.Tag.LANGUAGE:
+                return self.data.decode("ascii")
+
+            if self.tag == Metadata.Tag.CCID_LIST:
+                return list(self.data)
+
+            if self.tag == Metadata.Tag.PARENTAL_RATING:
+                return self.data[0]
+
+            if self.tag == Metadata.Tag.AUDIO_ACTIVE_STATE:
+                return AudioActiveState(self.data[0])
+
+            if self.tag == Metadata.Tag.ASSISTED_LISTENING_STREAM:
+                return AssistedListeningStream(self.data[0])
+
+            return self.data
+
         @classmethod
         def from_bytes(cls: Type[Self], data: bytes) -> Self:
             return cls(tag=Metadata.Tag(data[0]), data=data[1:])
@@ -66,6 +116,29 @@ class Metadata:
 
     entries: List[Entry] = dataclasses.field(default_factory=list)
 
+    def pretty_print(self, indent: str) -> str:
+        """Convenience method to generate a string with one key-value pair per line."""
+
+        max_key_length = 0
+        keys = []
+        values = []
+        for entry in self.entries:
+            key = entry.tag.name
+            max_key_length = max(max_key_length, len(key))
+            keys.append(key)
+            decoded = entry.decode()
+            if isinstance(decoded, enum.Enum):
+                values.append(decoded.name)
+            elif isinstance(decoded, bytes):
+                values.append(decoded.hex())
+            else:
+                values.append(str(decoded))
+
+        return '\n'.join(
+            f'{indent}{key}: {" " * (max_key_length-len(key))}{value}'
+            for key, value in zip(keys, values)
+        )
+
     @classmethod
     def from_bytes(cls: Type[Self], data: bytes) -> Self:
         entries = []
@@ -81,3 +154,13 @@ class Metadata:
 
     def __bytes__(self) -> bytes:
         return b''.join([bytes(entry) for entry in self.entries])
+
+    def __str__(self) -> str:
+        entries_str = []
+        for entry in self.entries:
+            decoded = entry.decode()
+            entries_str.append(
+                f'{entry.tag.name}: '
+                f'{decoded.hex() if isinstance(decoded, bytes) else decoded!r}'
+            )
+        return f'Metadata(entries={", ".join(entry_str for entry_str in entries_str)})'

bumble/profiles/mcp.py

@@ -208,7 +208,7 @@ class MediaControlService(gatt.TemplateService):
             properties=gatt.Characteristic.Properties.READ
             | gatt.Characteristic.Properties.NOTIFY,
             permissions=gatt.Characteristic.Permissions.READ_REQUIRES_ENCRYPTION,
-            value=media_player_name or 'Bumble Player',
+            value=(media_player_name or 'Bumble Player').encode(),
         )
         self.track_changed_characteristic = gatt.Characteristic(
             uuid=gatt.GATT_TRACK_CHANGED_CHARACTERISTIC,
@@ -247,14 +247,16 @@ class MediaControlService(gatt.TemplateService):
             permissions=gatt.Characteristic.Permissions.READ_REQUIRES_ENCRYPTION,
             value=b'',
         )
-        self.media_control_point_characteristic = gatt.Characteristic(
-            uuid=gatt.GATT_MEDIA_CONTROL_POINT_CHARACTERISTIC,
-            properties=gatt.Characteristic.Properties.WRITE
-            | gatt.Characteristic.Properties.WRITE_WITHOUT_RESPONSE
-            | gatt.Characteristic.Properties.NOTIFY,
-            permissions=gatt.Characteristic.Permissions.READ_REQUIRES_ENCRYPTION
-            | gatt.Characteristic.Permissions.WRITE_REQUIRES_ENCRYPTION,
-            value=gatt.CharacteristicValue(write=self.on_media_control_point),
+        self.media_control_point_characteristic: gatt.Characteristic[bytes] = (
+            gatt.Characteristic(
+                uuid=gatt.GATT_MEDIA_CONTROL_POINT_CHARACTERISTIC,
+                properties=gatt.Characteristic.Properties.WRITE
+                | gatt.Characteristic.Properties.WRITE_WITHOUT_RESPONSE
+                | gatt.Characteristic.Properties.NOTIFY,
+                permissions=gatt.Characteristic.Permissions.READ_REQUIRES_ENCRYPTION
+                | gatt.Characteristic.Permissions.WRITE_REQUIRES_ENCRYPTION,
+                value=gatt.CharacteristicValue(write=self.on_media_control_point),
+            )
         )
         self.media_control_point_opcodes_supported_characteristic = gatt.Characteristic(
             uuid=gatt.GATT_MEDIA_CONTROL_POINT_OPCODES_SUPPORTED_CHARACTERISTIC,

bumble/profiles/pacs.py

@@ -25,6 +25,7 @@ from typing import Optional, Sequence, Union
 from bumble.profiles.bap import AudioLocation, CodecSpecificCapabilities, ContextType
 from bumble.profiles import le_audio
 from bumble import gatt
+from bumble import gatt_adapters
 from bumble import gatt_client
 from bumble import hci
 
@@ -72,6 +73,19 @@ class PacRecord:
             metadata=metadata,
         )
 
+    @classmethod
+    def list_from_bytes(cls, data: bytes) -> list[PacRecord]:
+        """Parse a serialized list of records preceded by a one byte list length."""
+        record_count = data[0]
+        records = []
+        offset = 1
+        for _ in range(record_count):
+            record = PacRecord.from_bytes(data[offset:])
+            offset += len(bytes(record))
+            records.append(record)
+
+        return records
+
     def __bytes__(self) -> bytes:
         capabilities_bytes = bytes(self.codec_specific_capabilities)
         metadata_bytes = bytes(self.metadata)
@@ -172,39 +186,70 @@ class PublishedAudioCapabilitiesService(gatt.TemplateService):
 class PublishedAudioCapabilitiesServiceProxy(gatt_client.ProfileServiceProxy):
     SERVICE_CLASS = PublishedAudioCapabilitiesService
 
-    sink_pac: Optional[gatt_client.CharacteristicProxy] = None
-    sink_audio_locations: Optional[gatt_client.CharacteristicProxy] = None
-    source_pac: Optional[gatt_client.CharacteristicProxy] = None
-    source_audio_locations: Optional[gatt_client.CharacteristicProxy] = None
-    available_audio_contexts: gatt_client.CharacteristicProxy
-    supported_audio_contexts: gatt_client.CharacteristicProxy
+    sink_pac: Optional[gatt_client.CharacteristicProxy[list[PacRecord]]] = None
+    sink_audio_locations: Optional[gatt_client.CharacteristicProxy[AudioLocation]] = (
+        None
+    )
+    source_pac: Optional[gatt_client.CharacteristicProxy[list[PacRecord]]] = None
+    source_audio_locations: Optional[gatt_client.CharacteristicProxy[AudioLocation]] = (
+        None
+    )
+    available_audio_contexts: gatt_client.CharacteristicProxy[tuple[ContextType, ...]]
+    supported_audio_contexts: gatt_client.CharacteristicProxy[tuple[ContextType, ...]]
 
     def __init__(self, service_proxy: gatt_client.ServiceProxy):
         self.service_proxy = service_proxy
 
-        self.available_audio_contexts = service_proxy.get_characteristics_by_uuid(
-            gatt.GATT_AVAILABLE_AUDIO_CONTEXTS_CHARACTERISTIC
-        )[0]
-        self.supported_audio_contexts = service_proxy.get_characteristics_by_uuid(
-            gatt.GATT_SUPPORTED_AUDIO_CONTEXTS_CHARACTERISTIC
-        )[0]
+        self.available_audio_contexts = (
+            gatt_adapters.DelegatedCharacteristicProxyAdapter(
+                service_proxy.get_required_characteristic_by_uuid(
+                    gatt.GATT_AVAILABLE_AUDIO_CONTEXTS_CHARACTERISTIC
+                ),
+                decode=lambda x: tuple(map(ContextType, struct.unpack('<HH', x))),
+            )
+        )
+
+        self.supported_audio_contexts = (
+            gatt_adapters.DelegatedCharacteristicProxyAdapter(
+                service_proxy.get_required_characteristic_by_uuid(
+                    gatt.GATT_SUPPORTED_AUDIO_CONTEXTS_CHARACTERISTIC
+                ),
+                decode=lambda x: tuple(map(ContextType, struct.unpack('<HH', x))),
+            )
+        )
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             gatt.GATT_SINK_PAC_CHARACTERISTIC
         ):
-            self.sink_pac = characteristics[0]
+            self.sink_pac = gatt_adapters.DelegatedCharacteristicProxyAdapter(
+                characteristics[0],
+                decode=PacRecord.list_from_bytes,
+            )
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             gatt.GATT_SOURCE_PAC_CHARACTERISTIC
         ):
-            self.source_pac = characteristics[0]
+            self.source_pac = gatt_adapters.DelegatedCharacteristicProxyAdapter(
+                characteristics[0],
+                decode=PacRecord.list_from_bytes,
+            )
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             gatt.GATT_SINK_AUDIO_LOCATION_CHARACTERISTIC
         ):
-            self.sink_audio_locations = characteristics[0]
+            self.sink_audio_locations = (
+                gatt_adapters.DelegatedCharacteristicProxyAdapter(
+                    characteristics[0],
+                    decode=lambda x: AudioLocation(struct.unpack('<I', x)[0]),
+                )
+            )
 
         if characteristics := service_proxy.get_characteristics_by_uuid(
             gatt.GATT_SOURCE_AUDIO_LOCATION_CHARACTERISTIC
         ):
-            self.source_audio_locations = characteristics[0]
+            self.source_audio_locations = (
+                gatt_adapters.DelegatedCharacteristicProxyAdapter(
+                    characteristics[0],
+                    decode=lambda x: AudioLocation(struct.unpack('<I', x)[0]),
+                )
+            )

bumble/profiles/tmap.py

@@ -24,12 +24,11 @@ import struct
 from bumble.gatt import (
     TemplateService,
     Characteristic,
-    DelegatedCharacteristicAdapter,
-    InvalidServiceError,
     GATT_TELEPHONY_AND_MEDIA_AUDIO_SERVICE,
     GATT_TMAP_ROLE_CHARACTERISTIC,
 )
-from bumble.gatt_client import ProfileServiceProxy, ServiceProxy
+from bumble.gatt_adapters import DelegatedCharacteristicProxyAdapter
+from bumble.gatt_client import CharacteristicProxy, ProfileServiceProxy, ServiceProxy
 
 
 # -----------------------------------------------------------------------------
@@ -54,6 +53,8 @@ class Role(enum.IntFlag):
 class TelephonyAndMediaAudioService(TemplateService):
     UUID = GATT_TELEPHONY_AND_MEDIA_AUDIO_SERVICE
 
+    role_characteristic: Characteristic[bytes]
+
     def __init__(self, role: Role):
         self.role_characteristic = Characteristic(
             GATT_TMAP_ROLE_CHARACTERISTIC,
@@ -69,20 +70,15 @@ class TelephonyAndMediaAudioService(TemplateService):
 class TelephonyAndMediaAudioServiceProxy(ProfileServiceProxy):
     SERVICE_CLASS = TelephonyAndMediaAudioService
 
-    role: DelegatedCharacteristicAdapter
+    role: CharacteristicProxy[Role]
 
     def __init__(self, service_proxy: ServiceProxy):
         self.service_proxy = service_proxy
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.role = DelegatedCharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_TMAP_ROLE_CHARACTERISTIC
-            )
-        ):
-            raise InvalidServiceError('TMAP Role characteristic not found')
-
-        self.role = DelegatedCharacteristicAdapter(
-            characteristics[0],
+            ),
             decode=lambda value: Role(
                 struct.unpack_from('<H', value, 0)[0],
             ),

bumble/profiles/vcs.py

@@ -1,4 +1,4 @@
-# Copyright 2021-2024 Google LLC
+# Copyright 2021-2025 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,14 +17,17 @@
 # Imports
 # -----------------------------------------------------------------------------
 from __future__ import annotations
+import dataclasses
 import enum
 
+from typing import Optional, Sequence
+
 from bumble import att
 from bumble import device
 from bumble import gatt
+from bumble import gatt_adapters
 from bumble import gatt_client
 
-from typing import Optional, Sequence
 
 # -----------------------------------------------------------------------------
 # Constants
@@ -67,6 +70,20 @@ class VolumeControlPointOpcode(enum.IntEnum):
     MUTE                        = 0x06
 
 
+@dataclasses.dataclass
+class VolumeState:
+    volume_setting: int
+    mute: int
+    change_counter: int
+
+    @classmethod
+    def from_bytes(cls, data: bytes) -> VolumeState:
+        return cls(data[0], data[1], data[2])
+
+    def __bytes__(self) -> bytes:
+        return bytes([self.volume_setting, self.mute, self.change_counter])
+
+
 # -----------------------------------------------------------------------------
 # Server
 # -----------------------------------------------------------------------------
@@ -126,16 +143,8 @@ class VolumeControlService(gatt.TemplateService):
             included_services=list(included_services),
         )
 
-    @property
-    def volume_state_bytes(self) -> bytes:
-        return bytes([self.volume_setting, self.muted, self.change_counter])
-
-    @volume_state_bytes.setter
-    def volume_state_bytes(self, new_value: bytes) -> None:
-        self.volume_setting, self.muted, self.change_counter = new_value
-
     def _on_read_volume_state(self, _connection: Optional[device.Connection]) -> bytes:
-        return self.volume_state_bytes
+        return bytes(VolumeState(self.volume_setting, self.muted, self.change_counter))
 
     def _on_write_volume_control_point(
         self, connection: Optional[device.Connection], value: bytes
@@ -153,14 +162,9 @@ class VolumeControlService(gatt.TemplateService):
             self.change_counter = (self.change_counter + 1) % 256
             connection.abort_on(
                 'disconnection',
-                connection.device.notify_subscribers(
-                    attribute=self.volume_state,
-                    value=self.volume_state_bytes,
-                ),
-            )
-            self.emit(
-                'volume_state', self.volume_setting, self.muted, self.change_counter
+                connection.device.notify_subscribers(attribute=self.volume_state),
             )
+            self.emit('volume_state_change')
 
     def _on_relative_volume_down(self) -> bool:
         old_volume = self.volume_setting
@@ -206,25 +210,27 @@ class VolumeControlService(gatt.TemplateService):
 class VolumeControlServiceProxy(gatt_client.ProfileServiceProxy):
     SERVICE_CLASS = VolumeControlService
 
-    volume_control_point: gatt_client.CharacteristicProxy
+    volume_control_point: gatt_client.CharacteristicProxy[bytes]
+    volume_state: gatt_client.CharacteristicProxy[VolumeState]
+    volume_flags: gatt_client.CharacteristicProxy[VolumeFlags]
 
     def __init__(self, service_proxy: gatt_client.ServiceProxy) -> None:
         self.service_proxy = service_proxy
 
-        self.volume_state = gatt.PackedCharacteristicAdapter(
-            service_proxy.get_characteristics_by_uuid(
+        self.volume_state = gatt_adapters.SerializableCharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 gatt.GATT_VOLUME_STATE_CHARACTERISTIC
-            )[0],
-            'BBB',
+            ),
+            VolumeState,
         )
 
-        self.volume_control_point = service_proxy.get_characteristics_by_uuid(
+        self.volume_control_point = service_proxy.get_required_characteristic_by_uuid(
             gatt.GATT_VOLUME_CONTROL_POINT_CHARACTERISTIC
-        )[0]
-
-        self.volume_flags = gatt.PackedCharacteristicAdapter(
-            service_proxy.get_characteristics_by_uuid(
-                gatt.GATT_VOLUME_FLAGS_CHARACTERISTIC
-            )[0],
-            'B',
+        )
+
+        self.volume_flags = gatt_adapters.DelegatedCharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
+                gatt.GATT_VOLUME_FLAGS_CHARACTERISTIC
+            ),
+            decode=lambda data: VolumeFlags(data[0]),
         )

bumble/profiles/vocs.py

@@ -24,17 +24,19 @@ from bumble.device import Connection
 from bumble.att import ATT_Error
 from bumble.gatt import (
     Characteristic,
-    DelegatedCharacteristicAdapter,
     TemplateService,
     CharacteristicValue,
-    UTF8CharacteristicAdapter,
-    InvalidServiceError,
     GATT_VOLUME_OFFSET_CONTROL_SERVICE,
     GATT_VOLUME_OFFSET_STATE_CHARACTERISTIC,
     GATT_AUDIO_LOCATION_CHARACTERISTIC,
     GATT_VOLUME_OFFSET_CONTROL_POINT_CHARACTERISTIC,
     GATT_AUDIO_OUTPUT_DESCRIPTION_CHARACTERISTIC,
 )
+from bumble.gatt_adapters import (
+    DelegatedCharacteristicProxyAdapter,
+    SerializableCharacteristicProxyAdapter,
+    UTF8CharacteristicProxyAdapter,
+)
 from bumble.gatt_client import ProfileServiceProxy, ServiceProxy
 from bumble.utils import OpenIntEnum
 from bumble.profiles.bap import AudioLocation
@@ -67,7 +69,7 @@ class ErrorCode(OpenIntEnum):
 class VolumeOffsetState:
     volume_offset: int = 0
     change_counter: int = 0
-    attribute_value: Optional[CharacteristicValue] = None
+    attribute: Optional[Characteristic] = None
 
     def __bytes__(self) -> bytes:
         return struct.pack('<hB', self.volume_offset, self.change_counter)
@@ -81,10 +83,8 @@ class VolumeOffsetState:
         self.change_counter = (self.change_counter + 1) % (CHANGE_COUNTER_MAX_VALUE + 1)
 
     async def notify_subscribers_via_connection(self, connection: Connection) -> None:
-        assert self.attribute_value is not None
-        await connection.device.notify_subscribers(
-            attribute=self.attribute_value, value=bytes(self)
-        )
+        assert self.attribute is not None
+        await connection.device.notify_subscribers(attribute=self.attribute)
 
     def on_read(self, _connection: Optional[Connection]) -> bytes:
         return bytes(self)
@@ -93,7 +93,7 @@ class VolumeOffsetState:
 @dataclass
 class VocsAudioLocation:
     audio_location: AudioLocation = AudioLocation.NOT_ALLOWED
-    attribute_value: Optional[CharacteristicValue] = None
+    attribute: Optional[Characteristic] = None
 
     def __bytes__(self) -> bytes:
         return struct.pack('<I', self.audio_location)
@@ -108,12 +108,10 @@ class VocsAudioLocation:
 
     async def on_write(self, connection: Optional[Connection], value: bytes) -> None:
         assert connection
-        assert self.attribute_value
+        assert self.attribute
 
         self.audio_location = AudioLocation(int.from_bytes(value, 'little'))
-        await connection.device.notify_subscribers(
-            attribute=self.attribute_value, value=value
-        )
+        await connection.device.notify_subscribers(attribute=self.attribute)
 
 
 @dataclass
@@ -152,7 +150,7 @@ class VolumeOffsetControlPoint:
 @dataclass
 class AudioOutputDescription:
     audio_output_description: str = ''
-    attribute_value: Optional[CharacteristicValue] = None
+    attribute: Optional[Characteristic] = None
 
     @classmethod
     def from_bytes(cls, data: bytes):
@@ -166,12 +164,10 @@ class AudioOutputDescription:
 
     async def on_write(self, connection: Optional[Connection], value: bytes) -> None:
         assert connection
-        assert self.attribute_value
+        assert self.attribute
 
         self.audio_output_description = value.decode('utf-8')
-        await connection.device.notify_subscribers(
-            attribute=self.attribute_value, value=value
-        )
+        await connection.device.notify_subscribers(attribute=self.attribute)
 
 
 # -----------------------------------------------------------------------------
@@ -203,48 +199,45 @@ class VolumeOffsetControlService(TemplateService):
             VolumeOffsetControlPoint(self.volume_offset_state)
         )
 
-        self.volume_offset_state_characteristic = DelegatedCharacteristicAdapter(
-            Characteristic(
-                uuid=GATT_VOLUME_OFFSET_STATE_CHARACTERISTIC,
-                properties=(
-                    Characteristic.Properties.READ | Characteristic.Properties.NOTIFY
-                ),
-                permissions=Characteristic.Permissions.READ_REQUIRES_ENCRYPTION,
-                value=CharacteristicValue(read=self.volume_offset_state.on_read),
+        self.volume_offset_state_characteristic: Characteristic[bytes] = Characteristic(
+            uuid=GATT_VOLUME_OFFSET_STATE_CHARACTERISTIC,
+            properties=(
+                Characteristic.Properties.READ | Characteristic.Properties.NOTIFY
             ),
-            encode=lambda value: bytes(value),
+            permissions=Characteristic.Permissions.READ_REQUIRES_ENCRYPTION,
+            value=CharacteristicValue(read=self.volume_offset_state.on_read),
         )
 
-        self.audio_location_characteristic = DelegatedCharacteristicAdapter(
+        self.audio_location_characteristic: Characteristic[bytes] = Characteristic(
+            uuid=GATT_AUDIO_LOCATION_CHARACTERISTIC,
+            properties=(
+                Characteristic.Properties.READ
+                | Characteristic.Properties.NOTIFY
+                | Characteristic.Properties.WRITE_WITHOUT_RESPONSE
+            ),
+            permissions=(
+                Characteristic.Permissions.READ_REQUIRES_ENCRYPTION
+                | Characteristic.Permissions.WRITE_REQUIRES_ENCRYPTION
+            ),
+            value=CharacteristicValue(
+                read=self.audio_location.on_read,
+                write=self.audio_location.on_write,
+            ),
+        )
+        self.audio_location.attribute = self.audio_location_characteristic
+
+        self.volume_offset_control_point_characteristic: Characteristic[bytes] = (
             Characteristic(
-                uuid=GATT_AUDIO_LOCATION_CHARACTERISTIC,
-                properties=(
-                    Characteristic.Properties.READ
-                    | Characteristic.Properties.NOTIFY
-                    | Characteristic.Properties.WRITE_WITHOUT_RESPONSE
-                ),
-                permissions=(
-                    Characteristic.Permissions.READ_REQUIRES_ENCRYPTION
-                    | Characteristic.Permissions.WRITE_REQUIRES_ENCRYPTION
-                ),
+                uuid=GATT_VOLUME_OFFSET_CONTROL_POINT_CHARACTERISTIC,
+                properties=Characteristic.Properties.WRITE,
+                permissions=Characteristic.Permissions.WRITE_REQUIRES_ENCRYPTION,
                 value=CharacteristicValue(
-                    read=self.audio_location.on_read,
-                    write=self.audio_location.on_write,
+                    write=self.volume_offset_control_point.on_write
                 ),
-            ),
-            encode=lambda value: bytes(value),
-            decode=VocsAudioLocation.from_bytes,
-        )
-        self.audio_location.attribute_value = self.audio_location_characteristic.value
-
-        self.volume_offset_control_point_characteristic = Characteristic(
-            uuid=GATT_VOLUME_OFFSET_CONTROL_POINT_CHARACTERISTIC,
-            properties=Characteristic.Properties.WRITE,
-            permissions=Characteristic.Permissions.WRITE_REQUIRES_ENCRYPTION,
-            value=CharacteristicValue(write=self.volume_offset_control_point.on_write),
+            )
         )
 
-        self.audio_output_description_characteristic = DelegatedCharacteristicAdapter(
+        self.audio_output_description_characteristic: Characteristic[bytes] = (
             Characteristic(
                 uuid=GATT_AUDIO_OUTPUT_DESCRIPTION_CHARACTERISTIC,
                 properties=(
@@ -262,9 +255,8 @@ class VolumeOffsetControlService(TemplateService):
                 ),
             )
         )
-
-        self.audio_output_description.attribute_value = (
-            self.audio_output_description_characteristic.value
+        self.audio_output_description.attribute = (
+            self.audio_output_description_characteristic
         )
 
         super().__init__(
@@ -287,44 +279,29 @@ class VolumeOffsetControlServiceProxy(ProfileServiceProxy):
     def __init__(self, service_proxy: ServiceProxy) -> None:
         self.service_proxy = service_proxy
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.volume_offset_state = SerializableCharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_VOLUME_OFFSET_STATE_CHARACTERISTIC
-            )
-        ):
-            raise InvalidServiceError("Volume Offset State characteristic not found")
-        self.volume_offset_state = DelegatedCharacteristicAdapter(
-            characteristics[0], decode=VolumeOffsetState.from_bytes
+            ),
+            VolumeOffsetState,
         )
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.audio_location = DelegatedCharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_AUDIO_LOCATION_CHARACTERISTIC
-            )
-        ):
-            raise InvalidServiceError("Audio Location characteristic not found")
-        self.audio_location = DelegatedCharacteristicAdapter(
-            characteristics[0],
-            encode=lambda value: bytes(value),
-            decode=VocsAudioLocation.from_bytes,
+            ),
+            encode=lambda value: bytes([int(value)]),
+            decode=lambda data: AudioLocation(data[0]),
         )
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.volume_offset_control_point = (
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_VOLUME_OFFSET_CONTROL_POINT_CHARACTERISTIC
             )
-        ):
-            raise InvalidServiceError(
-                "Volume Offset Control Point characteristic not found"
-            )
-        self.volume_offset_control_point = characteristics[0]
+        )
 
-        if not (
-            characteristics := service_proxy.get_characteristics_by_uuid(
+        self.audio_output_description = UTF8CharacteristicProxyAdapter(
+            service_proxy.get_required_characteristic_by_uuid(
                 GATT_AUDIO_OUTPUT_DESCRIPTION_CHARACTERISTIC
             )
-        ):
-            raise InvalidServiceError(
-                "Audio Output Description characteristic not found"
-            )
-        self.audio_output_description = UTF8CharacteristicAdapter(characteristics[0])
+        )

bumble/utils.py

@@ -502,3 +502,13 @@ class ByteSerializable(Protocol):
     def from_bytes(cls, data: bytes) -> Self: ...
 
     def __bytes__(self) -> bytes: ...
+
+
+# -----------------------------------------------------------------------------
+class IntConvertible(Protocol):
+    """
+    Type protocol for classes that can be instantiated from int and converted to int.
+    """
+
+    def __init__(self, value: int) -> None: ...
+    def __int__(self) -> int: ...

docs/mkdocs/mkdocs.yml

@@ -39,12 +39,14 @@ nav:
   - Drivers:
     - drivers/index.md
     - Realtek: drivers/realtek.md
+    - Intel: drivers/intel.md
   - API:
     - Guide: api/guide.md
     - Examples: api/examples.md
     - Reference: api/reference.md
   - Apps & Tools:
     - apps_and_tools/index.md
+    - Auracast: apps_and_tools/auracast.md
     - Console: apps_and_tools/console.md
     - Bench: apps_and_tools/bench.md
     - Speaker: apps_and_tools/speaker.md
@@ -108,8 +110,8 @@ markdown_extensions:
   - pymdownx.details
   - pymdownx.superfences
   - pymdownx.emoji:
-      emoji_index: !!python/name:materialx.emoji.twemoji
-      emoji_generator: !!python/name:materialx.emoji.to_svg
+      emoji_index: !!python/name:material.extensions.emoji.twemoji
+      emoji_generator: !!python/name:material.extensions.emoji.to_svg
   - pymdownx.tabbed:
       alternate_style: true
   - codehilite:

docs/mkdocs/src/apps_and_tools/index.md

@@ -4,12 +4,13 @@ APPS & TOOLS
 Included in the project are a few apps and tools, built on top of the core libraries.
 These include:
 
-  * [Console](console.md) - an interactive text-based console
-  * [Bench](bench.md) - Speed and Latency benchmarking between two devices (LE and Classic)
-  * [Pair](pair.md) - Pair/bond two devices (LE and Classic)
-  * [Unbond](unbond.md) - Remove a previously established bond
-  * [HCI Bridge](hci_bridge.md) - a HCI transport bridge to connect two HCI transports and filter/snoop the HCI packets
-  * [Golden Gate Bridge](gg_bridge.md) - a bridge between GATT and UDP to use with the Golden Gate "stack tool"
-  * [Show](show.md) - Parse a file with HCI packets and print the details of each packet in a human readable form
+  * [Auracast](auracast.md) - Commands to broadcast, receive and/or control LE Audio.
+  * [Console](console.md) - An interactive text-based console.
+  * [Bench](bench.md) - Speed and Latency benchmarking between two devices (LE and Classic).
+  * [Pair](pair.md) - Pair/bond two devices (LE and Classic).
+  * [Unbond](unbond.md) - Remove a previously established bond.
+  * [HCI Bridge](hci_bridge.md) - An HCI transport bridge to connect two HCI transports and filter/snoop the HCI packets.
+  * [Golden Gate Bridge](gg_bridge.md) - Bridge between GATT and UDP to use with the Golden Gate "stack tool".
+  * [Show](show.md) - Parse a file with HCI packets and print the details of each packet in a human readable form.
   * [Speaker](speaker.md) - Virtual Bluetooth speaker, with a command line and browser-based UI.
   * [Link Relay](link_relay.md) - WebSocket relay for virtual RemoteLink instances to communicate with each other.

docs/mkdocs/src/getting_started.md

@@ -9,9 +9,9 @@ for your platform.
 Throughout the documentation, when shell commands are shown, it is assumed that you can
 invoke Python as
 ```
-$ python
+$ python3
 ```
-If invoking python is different on your platform (it may be `python3` for example, or just `py` or `py.exe`),
+If invoking python is different on your platform (it may be `python` for example, or just `py` or `py.exe`),
 adjust accordingly.
 
 You may be simply using Bumble as a module for your own application or as a dependency to your own
@@ -30,12 +30,18 @@ manager, or from source.
     python environment, or in a virtual environment, such as a `venv`, `pyenv` or `conda` environment.
     See the [Python Environments page](development/python_environments.md) page for details.
 
+### Install from PyPI
+
+```
+$ python3 -m pip install bumble
+```
+
 ### Install From Source
 
 Install with `pip`. Run in a command shell in the directory where you downloaded the source
 distribution
 ```
-$ python -m pip install -e .
+$ python3 -m pip install -e .
 ```
 
 ### Install from GitHub
@@ -44,21 +50,21 @@ You can install directly from GitHub without first downloading the repo.
 
 Install the latest commit from the main branch with `pip`:
 ```
-$ python -m pip install git+https://github.com/google/bumble.git
+$ python3 -m pip install git+https://github.com/google/bumble.git
 ```
 
 You can specify a specific tag.
 
 Install tag `v0.0.1` with `pip`:
 ```
-$ python -m pip install git+https://github.com/google/bumble.git@v0.0.1
+$ python3 -m pip install git+https://github.com/google/bumble.git@v0.0.1
 ```
 
 You can also specify a specific commit.
 
 Install commit `27c0551` with `pip`:
 ```
-$ python -m pip install git+https://github.com/google/bumble.git@27c0551
+$ python3 -m pip install git+https://github.com/google/bumble.git@27c0551
 ```
 
 # Working On The Bumble Code
@@ -78,21 +84,21 @@ directory of the project.
 
 ```bash
 $ export PYTHONPATH=.
-$ python apps/console.py serial:/dev/tty.usbmodem0006839912171
+$ python3 apps/console.py serial:/dev/tty.usbmodem0006839912171
 ```
 
 or running an example, with the working directory set to the `examples` subdirectory
 ```bash
 $ cd examples
 $ export PYTHONPATH=..
-$ python run_scanner.py usb:0
+$ python3 run_scanner.py usb:0
 ```
 
 Or course, `export PYTHONPATH` only needs to be invoked once, not before each app/script execution.
 
 Setting `PYTHONPATH` locally with each command would look something like:
 ```
-$ PYTHONPATH=. python examples/run_advertiser.py examples/device1.json serial:/dev/tty.usbmodem0006839912171
+$ PYTHONPATH=. python3 examples/run_advertiser.py examples/device1.json serial:/dev/tty.usbmodem0006839912171
 ```
 
 # Where To Go Next

docs/mkdocs/src/platforms/android.md

@@ -35,11 +35,11 @@ the command line.
     visit [this Android Studio user guide page](https://developer.android.com/studio/run/emulator-commandline)
 
 The `-packet-streamer-endpoint <endpoint>` command line option may be used to enable
-Bluetooth emulation and tell the emulator which virtual controller to connect to. 
+Bluetooth emulation and tell the emulator which virtual controller to connect to.
 
 ## Connecting to Netsim
 
-If the emulator doesn't have Bluetooth emulation enabled by default, use the 
+If the emulator doesn't have Bluetooth emulation enabled by default, use the
 `-packet-streamer-endpoint default` option to tell it to connect to Netsim.
 If Netsim is not running, the emulator will start it automatically.
 
@@ -60,17 +60,17 @@ the Bumble `android-netsim` transport in `host` mode (the default).
 
 !!! example "Run the example GATT server connected to the emulator via Netsim"
     ``` shell
-    $ python run_gatt_server.py device1.json android-netsim
+    $ python3 run_gatt_server.py device1.json android-netsim
     ```
 
 By default, the Bumble `android-netsim` transport will try to automatically discover
 the port number on which the netsim process is exposing its gRPC server interface. If
-that discovery process fails, or if you want to specify the interface manually, you 
+that discovery process fails, or if you want to specify the interface manually, you
 can pass a `hostname` and `port` as parameters to the transport, as: `android-netsim:<host>:<port>`.
 
 !!! example "Run the example GATT server connected to the emulator via Netsim on a localhost, port 8877"
     ``` shell
-    $ python run_gatt_server.py device1.json android-netsim:localhost:8877
+    $ python3 run_gatt_server.py device1.json android-netsim:localhost:8877
     ```
 
 ### Multiple Instances
@@ -84,7 +84,7 @@ For example: `android-netsim:localhost:8877,name=bumble1`
 This is an advanced use case, which may not be officially supported, but should work in recent
 versions of the emulator.
 
-The first step is to run the Bumble HCI bridge, specifying netsim as the "host" end of the 
+The first step is to run the Bumble HCI bridge, specifying netsim as the "host" end of the
 bridge, and another controller (typically a USB Bluetooth dongle, but any other supported
 transport can work as well) as the "controller" end of the bridge.
 

examples/heart_rate_server.py

@@ -102,7 +102,6 @@ async def main() -> None:
         )
 
         # Notify subscribers of the current value as soon as they subscribe
-        @heart_rate_service.heart_rate_measurement_characteristic.on('subscription')
         def on_subscription(connection, notify_enabled, indicate_enabled):
             if notify_enabled or indicate_enabled:
                 AsyncRunner.spawn(
@@ -112,6 +111,10 @@ async def main() -> None:
                     )
                 )
 
+        heart_rate_service.heart_rate_measurement_characteristic.on(
+            'subscription', on_subscription
+        )
+
         # Go!
         await device.power_on()
         await device.start_advertising(auto_restart=True)

examples/mobly/bench/one_device_bench_test.py

@@ -28,7 +28,7 @@ class OneDeviceBenchTest(base_test.BaseTestClass):
 
     def test_l2cap_client_ping(self):
         runner = self.dut.bench.runL2capClient(
-            "ping", "4B:2A:67:76:2B:E3", 128, True, 100, 970, 100
+            "ping", "4B:2A:67:76:2B:E3", 128, True, 100, 970, 100, "HIGH"
         )
         print("### Initial status:", runner)
         final_status = self.dut.bench.waitForRunnerCompletion(runner["id"])
@@ -36,12 +36,34 @@ class OneDeviceBenchTest(base_test.BaseTestClass):
 
     def test_l2cap_client_send(self):
         runner = self.dut.bench.runL2capClient(
-            "send", "7E:90:D0:F2:7A:11", 131, True, 100, 970, 0
+            "send",
+            "F1:F1:F1:F1:F1:F1",
+            128,
+            True,
+            100,
+            970,
+            0,
+            "HIGH",
+            10000,
         )
         print("### Initial status:", runner)
         final_status = self.dut.bench.waitForRunnerCompletion(runner["id"])
         print("### Final status:", final_status)
 
+    def test_gatt_client_send(self):
+        runner = self.dut.bench.runGattClient(
+            "send", "F1:F1:F1:F1:F1:F1", 128, True, 100, 970, 100, "HIGH"
+        )
+        print("### Initial status:", runner)
+        final_status = self.dut.bench.waitForRunnerCompletion(runner["id"])
+        print("### Final status:", final_status)
+
+    def test_gatt_server_receive(self):
+        runner = self.dut.bench.runGattServer("receive")
+        print("### Initial status:", runner)
+        final_status = self.dut.bench.waitForRunnerCompletion(runner["id"])
+        print("### Final status:", final_status)
+
 
 if __name__ == "__main__":
     test_runner.main()

examples/mobly/bench/sample_config.yml

@@ -2,8 +2,8 @@ TestBeds:
   - Name: BenchTestBed
     Controllers:
         AndroidDevice:
-          - serial: 37211FDJG000DJ
+          - serial: emulator-5554
             local_bt_address: 94:45:60:5E:03:B0
 
-          - serial: 23071FDEE001F7
-            local_bt_address: DC:E5:5B:E5:51:2C
+          #- serial: 23071FDEE001F7
+          #  local_bt_address: DC:E5:5B:E5:51:2C

examples/run_gatt_client_and_server.py

@@ -70,13 +70,13 @@ async def main() -> None:
     descriptor = Descriptor(
         GATT_CHARACTERISTIC_USER_DESCRIPTION_DESCRIPTOR,
         Descriptor.READABLE,
-        'My Description',
+        'My Description'.encode(),
     )
-    manufacturer_name_characteristic = Characteristic(
+    manufacturer_name_characteristic = Characteristic[bytes](
         GATT_MANUFACTURER_NAME_STRING_CHARACTERISTIC,
         Characteristic.Properties.READ,
         Characteristic.READABLE,
-        "Fitbit",
+        "Fitbit".encode(),
         [descriptor],
     )
     device_info_service = Service(

examples/run_gatt_server.py

@@ -94,13 +94,13 @@ async def main() -> None:
         descriptor = Descriptor(
             GATT_CHARACTERISTIC_USER_DESCRIPTION_DESCRIPTOR,
             Descriptor.READABLE,
-            'My Description',
+            'My Description'.encode(),
         )
         manufacturer_name_characteristic = Characteristic(
             GATT_MANUFACTURER_NAME_STRING_CHARACTERISTIC,
             Characteristic.Properties.READ,
             Characteristic.READABLE,
-            'Fitbit',
+            'Fitbit'.encode(),
             [descriptor],
         )
         device_info_service = Service(

examples/run_gatt_with_adapters.py

@@ -1,4 +1,4 @@
-# Copyright 2024 Google LLC
+# Copyright 2025 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -18,6 +18,8 @@
 from __future__ import annotations
 import asyncio
 import dataclasses
+import functools
+import enum
 import logging
 import os
 import random
@@ -25,9 +27,11 @@ import struct
 import sys
 from typing import Any, List, Union
 
-from bumble.device import Connection, Device, Peer
+from bumble.device import Device, Peer
 from bumble import transport
 from bumble import gatt
+from bumble import gatt_adapters
+from bumble import gatt_client
 from bumble import hci
 from bumble import core
 
@@ -36,6 +40,9 @@ from bumble import core
 SERVICE_UUID = core.UUID("50DB505C-8AC4-4738-8448-3B1D9CC09CC5")
 CHARACTERISTIC_UUID_BASE = "D901B45B-4916-412E-ACCA-0000000000"
 
+DEFAULT_CLIENT_ADDRESS = "F0:F1:F2:F3:F4:F5"
+DEFAULT_SERVER_ADDRESS = "F1:F2:F3:F4:F5:F6"
+
 
 # -----------------------------------------------------------------------------
 @dataclasses.dataclass
@@ -65,6 +72,12 @@ class CustomClass:
         return struct.pack(">II", self.a, self.b)
 
 
+# -----------------------------------------------------------------------------
+class CustomEnum(enum.IntEnum):
+    FOO = 1234
+    BAR = 5678
+
+
 # -----------------------------------------------------------------------------
 async def client(device: Device, address: hci.Address) -> None:
     print(f'=== Connecting to {address}...')
@@ -78,72 +91,105 @@ async def client(device: Device, address: hci.Address) -> None:
     print("*** Discovery complete")
 
     service = peer.get_services_by_uuid(SERVICE_UUID)[0]
-    characteristics = []
-    for index in range(1, 9):
+    characteristics: list[gatt_client.CharacteristicProxy] = []
+    for index in range(1, 10):
         characteristics.append(
             service.get_characteristics_by_uuid(
-                CHARACTERISTIC_UUID_BASE + f"{index:02X}"
+                core.UUID(CHARACTERISTIC_UUID_BASE + f"{index:02X}")
             )[0]
         )
 
     # Read all characteristics as raw bytes.
     for characteristic in characteristics:
         value = await characteristic.read_value()
-        print(f"### {characteristic} = {value} ({value.hex()})")
+        print(f"### {characteristic} = {value!r} ({value.hex()})")
+
+    # Subscribe to all characteristics as a raw bytes listener.
+    def on_raw_characteristic_update(characteristic, value):
+        print(f"^^^ Update[RAW] {characteristic.uuid} value = {value.hex()}")
+
+    for characteristic in characteristics:
+        await characteristic.subscribe(
+            functools.partial(on_raw_characteristic_update, characteristic)
+        )
+
+    # Function to subscribe to adapted characteristics
+    def on_adapted_characteristic_update(characteristic, value):
+        print(
+            f"^^^ Update[ADAPTED] {characteristic.uuid} value = {value!r}, "
+            f"type={type(value)}"
+        )
 
     # Static characteristic with a bytes value.
     c1 = characteristics[0]
     c1_value = await c1.read_value()
-    print(f"@@@ C1 {c1} value = {c1_value} (type={type(c1_value)})")
+    print(f"@@@ C1 {c1} value = {c1_value!r} (type={type(c1_value)})")
     await c1.write_value("happy π day".encode("utf-8"))
+    await c1.subscribe(functools.partial(on_adapted_characteristic_update, c1))
 
     # Static characteristic with a string value.
-    c2 = gatt.UTF8CharacteristicAdapter(characteristics[1])
+    c2 = gatt_adapters.UTF8CharacteristicProxyAdapter(characteristics[1])
     c2_value = await c2.read_value()
     print(f"@@@ C2 {c2} value = {c2_value} (type={type(c2_value)})")
     await c2.write_value("happy π day")
+    await c2.subscribe(functools.partial(on_adapted_characteristic_update, c2))
 
     # Static characteristic with a tuple value.
-    c3 = gatt.PackedCharacteristicAdapter(characteristics[2], ">III")
+    c3 = gatt_adapters.PackedCharacteristicProxyAdapter(characteristics[2], ">III")
     c3_value = await c3.read_value()
     print(f"@@@ C3 {c3} value = {c3_value} (type={type(c3_value)})")
     await c3.write_value((2001, 2002, 2003))
+    await c3.subscribe(functools.partial(on_adapted_characteristic_update, c3))
 
     # Static characteristic with a named tuple value.
-    c4 = gatt.MappedCharacteristicAdapter(
+    c4 = gatt_adapters.MappedCharacteristicProxyAdapter(
         characteristics[3], ">III", ["f1", "f2", "f3"]
     )
     c4_value = await c4.read_value()
     print(f"@@@ C4 {c4} value = {c4_value} (type={type(c4_value)})")
     await c4.write_value({"f1": 4001, "f2": 4002, "f3": 4003})
+    await c4.subscribe(functools.partial(on_adapted_characteristic_update, c4))
 
     # Static characteristic with a serializable value.
-    c5 = gatt.SerializableCharacteristicAdapter(
+    c5 = gatt_adapters.SerializableCharacteristicProxyAdapter(
         characteristics[4], CustomSerializableClass
     )
     c5_value = await c5.read_value()
     print(f"@@@ C5 {c5} value = {c5_value} (type={type(c5_value)})")
     await c5.write_value(CustomSerializableClass(56, 57))
+    await c5.subscribe(functools.partial(on_adapted_characteristic_update, c5))
 
     # Static characteristic with a delegated value.
-    c6 = gatt.DelegatedCharacteristicAdapter(
+    c6 = gatt_adapters.DelegatedCharacteristicProxyAdapter(
         characteristics[5], encode=CustomClass.encode, decode=CustomClass.decode
     )
     c6_value = await c6.read_value()
     print(f"@@@ C6 {c6} value = {c6_value} (type={type(c6_value)})")
     await c6.write_value(CustomClass(6, 7))
+    await c6.subscribe(functools.partial(on_adapted_characteristic_update, c6))
 
     # Dynamic characteristic with a bytes value.
     c7 = characteristics[6]
     c7_value = await c7.read_value()
-    print(f"@@@ C7 {c7} value = {c7_value} (type={type(c7_value)})")
+    print(f"@@@ C7 {c7} value = {c7_value!r} (type={type(c7_value)})")
     await c7.write_value(bytes.fromhex("01020304"))
+    await c7.subscribe(functools.partial(on_adapted_characteristic_update, c7))
 
     # Dynamic characteristic with a string value.
-    c8 = gatt.UTF8CharacteristicAdapter(characteristics[7])
+    c8 = gatt_adapters.UTF8CharacteristicProxyAdapter(characteristics[7])
     c8_value = await c8.read_value()
     print(f"@@@ C8 {c8} value = {c8_value} (type={type(c8_value)})")
     await c8.write_value("howdy")
+    await c8.subscribe(functools.partial(on_adapted_characteristic_update, c8))
+
+    # Static characteristic with an enum value
+    c9 = gatt_adapters.EnumCharacteristicProxyAdapter(
+        characteristics[8], CustomEnum, 3, 'big'
+    )
+    c9_value = await c9.read_value()
+    print(f"@@@ C9 {c9} value = {c9_value.name} (type={type(c9_value)})")
+    await c9.write_value(CustomEnum.BAR)
+    await c9.subscribe(functools.partial(on_adapted_characteristic_update, c9))
 
 
 # -----------------------------------------------------------------------------
@@ -175,142 +221,213 @@ def on_characteristic_write(characteristic: gatt.Characteristic, value: Any) ->
     print(f"<<< WRITE: {characteristic} <- {value}  ({type(value)})")
 
 
+# -----------------------------------------------------------------------------
+async def server(device: Device) -> None:
+    # Static characteristic with a bytes value.
+    c1 = gatt.Characteristic(
+        CHARACTERISTIC_UUID_BASE + "01",
+        gatt.Characteristic.Properties.READ
+        | gatt.Characteristic.Properties.WRITE
+        | gatt.Characteristic.Properties.NOTIFY,
+        gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
+        b'hello',
+    )
+
+    # Static characteristic with a string value.
+    c2 = gatt_adapters.UTF8CharacteristicAdapter(
+        gatt.Characteristic(
+            CHARACTERISTIC_UUID_BASE + "02",
+            gatt.Characteristic.Properties.READ
+            | gatt.Characteristic.Properties.WRITE
+            | gatt.Characteristic.Properties.NOTIFY,
+            gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
+            'hello',
+        )
+    )
+
+    # Static characteristic with a tuple value.
+    c3 = gatt_adapters.PackedCharacteristicAdapter(
+        gatt.Characteristic(
+            CHARACTERISTIC_UUID_BASE + "03",
+            gatt.Characteristic.Properties.READ
+            | gatt.Characteristic.Properties.WRITE
+            | gatt.Characteristic.Properties.NOTIFY,
+            gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
+            (1007, 1008, 1009),
+        ),
+        ">III",
+    )
+
+    # Static characteristic with a named tuple value.
+    c4 = gatt_adapters.MappedCharacteristicAdapter(
+        gatt.Characteristic(
+            CHARACTERISTIC_UUID_BASE + "04",
+            gatt.Characteristic.Properties.READ
+            | gatt.Characteristic.Properties.WRITE
+            | gatt.Characteristic.Properties.NOTIFY,
+            gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
+            {"f1": 3007, "f2": 3008, "f3": 3009},
+        ),
+        ">III",
+        ["f1", "f2", "f3"],
+    )
+
+    # Static characteristic with a serializable value.
+    c5 = gatt_adapters.SerializableCharacteristicAdapter(
+        gatt.Characteristic(
+            CHARACTERISTIC_UUID_BASE + "05",
+            gatt.Characteristic.Properties.READ
+            | gatt.Characteristic.Properties.WRITE
+            | gatt.Characteristic.Properties.NOTIFY,
+            gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
+            CustomSerializableClass(11, 12),
+        ),
+        CustomSerializableClass,
+    )
+
+    # Static characteristic with a delegated value.
+    c6 = gatt_adapters.DelegatedCharacteristicAdapter(
+        gatt.Characteristic(
+            CHARACTERISTIC_UUID_BASE + "06",
+            gatt.Characteristic.Properties.READ
+            | gatt.Characteristic.Properties.WRITE
+            | gatt.Characteristic.Properties.NOTIFY,
+            gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
+            CustomClass(1, 2),
+        ),
+        encode=CustomClass.encode,
+        decode=CustomClass.decode,
+    )
+
+    # Dynamic characteristic with a bytes value.
+    c7 = gatt.Characteristic(
+        CHARACTERISTIC_UUID_BASE + "07",
+        gatt.Characteristic.Properties.READ
+        | gatt.Characteristic.Properties.WRITE
+        | gatt.Characteristic.Properties.NOTIFY,
+        gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
+        gatt.CharacteristicValue(
+            read=lambda connection: dynamic_read("bytes"),
+            write=lambda connection, value: dynamic_write("bytes", value),
+        ),
+    )
+
+    # Dynamic characteristic with a string value.
+    c8 = gatt_adapters.UTF8CharacteristicAdapter(
+        gatt.Characteristic(
+            CHARACTERISTIC_UUID_BASE + "08",
+            gatt.Characteristic.Properties.READ
+            | gatt.Characteristic.Properties.WRITE
+            | gatt.Characteristic.Properties.NOTIFY,
+            gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
+            gatt.CharacteristicValue(
+                read=lambda connection: dynamic_read("string"),
+                write=lambda connection, value: dynamic_write("string", value),
+            ),
+        )
+    )
+
+    # Static characteristic with an enum value
+    c9 = gatt_adapters.EnumCharacteristicAdapter(
+        gatt.Characteristic(
+            CHARACTERISTIC_UUID_BASE + "09",
+            gatt.Characteristic.Properties.READ
+            | gatt.Characteristic.Properties.WRITE
+            | gatt.Characteristic.Properties.NOTIFY,
+            gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
+            CustomEnum.FOO,
+        ),
+        cls=CustomEnum,
+        length=3,
+        byteorder='big',
+    )
+
+    characteristics: List[gatt.Characteristic] = [
+        c1,
+        c2,
+        c3,
+        c4,
+        c5,
+        c6,
+        c7,
+        c8,
+        c9,
+    ]
+
+    # Listen for read and write events.
+    for characteristic in characteristics:
+        characteristic.on(
+            "read",
+            lambda _, value, c=characteristic: on_characteristic_read(c, value),
+        )
+        characteristic.on(
+            "write",
+            lambda _, value, c=characteristic: on_characteristic_write(c, value),
+        )
+
+    device.add_service(gatt.Service(SERVICE_UUID, characteristics))
+
+    # Notify every 3 seconds
+    i = 0
+    while True:
+        await asyncio.sleep(3)
+
+        # Notifying can be done with the characteristic's current value, or
+        # by explicitly passing a value to notify with. Both variants are used
+        # here: for c1..c4 we set the value and then notify, for c4..c9 we notify
+        # with an explicit value.
+        c1.value = f'hello c1 {i}'.encode()
+        await device.notify_subscribers(c1)
+        c2.value = f'hello c2 {i}'
+        await device.notify_subscribers(c2)
+        c3.value = (1000 + i, 2000 + i, 3000 + i)
+        await device.notify_subscribers(c3)
+        c4.value = {"f1": 4000 + i, "f2": 5000 + i, "f3": 6000 + i}
+        await device.notify_subscribers(c4)
+        await device.notify_subscribers(c5, CustomSerializableClass(1000 + i, 2000 + i))
+        await device.notify_subscribers(c6, CustomClass(3000 + i, 4000 + i))
+        await device.notify_subscribers(c7, bytes([1, 2, 3, i % 256]))
+        await device.notify_subscribers(c8, f'hello c8 {i}')
+        await device.notify_subscribers(
+            c9, CustomEnum.FOO if i % 2 == 0 else CustomEnum.BAR
+        )
+
+        i += 1
+
+
 # -----------------------------------------------------------------------------
 async def main() -> None:
     if len(sys.argv) < 2:
-        print("Usage: run_gatt_with_adapters.py <transport-spec> [<bluetooth-address>]")
-        print("example: run_gatt_with_adapters.py usb:0 E1:CA:72:48:C4:E8")
+        print("Usage: run_gatt_with_adapters.py <transport-spec> client|server")
+        print("example: run_gatt_with_adapters.py usb:0 F0:F1:F2:F3:F4:F5")
         return
 
     async with await transport.open_transport(sys.argv[1]) as hci_transport:
+        is_client = sys.argv[2] == "client"
+
         # Create a device to manage the host
         device = Device.with_hci(
             "Bumble",
-            hci.Address("F0:F1:F2:F3:F4:F5"),
+            hci.Address(
+                DEFAULT_CLIENT_ADDRESS if is_client else DEFAULT_SERVER_ADDRESS
+            ),
             hci_transport.source,
             hci_transport.sink,
         )
 
-        # Static characteristic with a bytes value.
-        c1 = gatt.Characteristic(
-            CHARACTERISTIC_UUID_BASE + "01",
-            gatt.Characteristic.Properties.READ | gatt.Characteristic.Properties.WRITE,
-            gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
-            b'hello',
-        )
-
-        # Static characteristic with a string value.
-        c2 = gatt.UTF8CharacteristicAdapter(
-            gatt.Characteristic(
-                CHARACTERISTIC_UUID_BASE + "02",
-                gatt.Characteristic.Properties.READ
-                | gatt.Characteristic.Properties.WRITE,
-                gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
-                'hello',
-            )
-        )
-
-        # Static characteristic with a tuple value.
-        c3 = gatt.PackedCharacteristicAdapter(
-            gatt.Characteristic(
-                CHARACTERISTIC_UUID_BASE + "03",
-                gatt.Characteristic.Properties.READ
-                | gatt.Characteristic.Properties.WRITE,
-                gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
-                (1007, 1008, 1009),
-            ),
-            ">III",
-        )
-
-        # Static characteristic with a named tuple value.
-        c4 = gatt.MappedCharacteristicAdapter(
-            gatt.Characteristic(
-                CHARACTERISTIC_UUID_BASE + "04",
-                gatt.Characteristic.Properties.READ
-                | gatt.Characteristic.Properties.WRITE,
-                gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
-                {"f1": 3007, "f2": 3008, "f3": 3009},
-            ),
-            ">III",
-            ["f1", "f2", "f3"],
-        )
-
-        # Static characteristic with a serializable value.
-        c5 = gatt.SerializableCharacteristicAdapter(
-            gatt.Characteristic(
-                CHARACTERISTIC_UUID_BASE + "05",
-                gatt.Characteristic.Properties.READ
-                | gatt.Characteristic.Properties.WRITE,
-                gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
-                CustomSerializableClass(11, 12),
-            ),
-            CustomSerializableClass,
-        )
-
-        # Static characteristic with a delegated value.
-        c6 = gatt.DelegatedCharacteristicAdapter(
-            gatt.Characteristic(
-                CHARACTERISTIC_UUID_BASE + "06",
-                gatt.Characteristic.Properties.READ
-                | gatt.Characteristic.Properties.WRITE,
-                gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
-                CustomClass(1, 2),
-            ),
-            encode=CustomClass.encode,
-            decode=CustomClass.decode,
-        )
-
-        # Dynamic characteristic with a bytes value.
-        c7 = gatt.Characteristic(
-            CHARACTERISTIC_UUID_BASE + "07",
-            gatt.Characteristic.Properties.READ | gatt.Characteristic.Properties.WRITE,
-            gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
-            gatt.CharacteristicValue(
-                read=lambda connection: dynamic_read("bytes"),
-                write=lambda connection, value: dynamic_write("bytes", value),
-            ),
-        )
-
-        # Dynamic characteristic with a string value.
-        c8 = gatt.UTF8CharacteristicAdapter(
-            gatt.Characteristic(
-                CHARACTERISTIC_UUID_BASE + "08",
-                gatt.Characteristic.Properties.READ
-                | gatt.Characteristic.Properties.WRITE,
-                gatt.Characteristic.READABLE | gatt.Characteristic.WRITEABLE,
-                gatt.CharacteristicValue(
-                    read=lambda connection: dynamic_read("string"),
-                    write=lambda connection, value: dynamic_write("string", value),
-                ),
-            )
-        )
-
-        characteristics: List[
-            Union[gatt.Characteristic, gatt.CharacteristicAdapter]
-        ] = [c1, c2, c3, c4, c5, c6, c7, c8]
-
-        # Listen for read and write events.
-        for characteristic in characteristics:
-            characteristic.on(
-                "read",
-                lambda _, value, c=characteristic: on_characteristic_read(c, value),
-            )
-            characteristic.on(
-                "write",
-                lambda _, value, c=characteristic: on_characteristic_write(c, value),
-            )
-
-        device.add_service(gatt.Service(SERVICE_UUID, characteristics))  # type: ignore
-
         # Get things going
         await device.power_on()
 
-        # Connect to a peer
-        if len(sys.argv) > 2:
-            await client(device, hci.Address(sys.argv[2]))
+        if is_client:
+            # Connect a client to a peer
+            await client(device, hci.Address(DEFAULT_SERVER_ADDRESS))
         else:
+            # Advertise so a peer can connect
             await device.start_advertising(auto_restart=True)
 
+            # Setup a server
+            await server(device)
+
         await hci_transport.source.wait_for_termination()
 
 

examples/run_vcp_renderer.py

@@ -42,7 +42,7 @@ from bumble.profiles.bap import (
 from bumble.profiles.pacs import PacRecord, PublishedAudioCapabilitiesService
 from bumble.profiles.cap import CommonAudioServiceService
 from bumble.profiles.csip import CoordinatedSetIdentificationService, SirkType
-from bumble.profiles.vcp import VolumeControlService
+from bumble.profiles.vcs import VolumeControlService
 
 from bumble.transport import open_transport_or_link
 
@@ -117,13 +117,17 @@ async def main() -> None:
 
         ws: Optional[websockets.WebSocketServerProtocol] = None
 
-        def on_volume_state(volume_setting: int, muted: int, change_counter: int):
+        def on_volume_state_change():
             if ws:
                 asyncio.create_task(
-                    ws.send(dumps_volume_state(volume_setting, muted, change_counter))
+                    ws.send(
+                        dumps_volume_state(
+                            vcs.volume_setting, vcs.muted, vcs.change_counter
+                        )
+                    )
                 )
 
-        vcs.on('volume_state', on_volume_state)
+        vcs.on('volume_state_change', on_volume_state_change)
 
         advertising_data = (
             bytes(
@@ -170,16 +174,10 @@ async def main() -> None:
             ws = websocket
             async for message in websocket:
                 volume_state = json.loads(message)
-                vcs.volume_state_bytes = bytes(
-                    [
-                        volume_state['volume_setting'],
-                        volume_state['muted'],
-                        volume_state['change_counter'],
-                    ]
-                )
-                await device.notify_subscribers(
-                    vcs.volume_state, vcs.volume_state_bytes
-                )
+                vcs.volume_setting = volume_state['volume_setting']
+                vcs.muted = volume_state['muted']
+                vcs.change_counter = volume_state['change_counter']
+                await device.notify_subscribers(vcs.volume_state)
             ws = None
 
         await websockets.serve(serve, 'localhost', 8989)

extras/android/BtBench/app/build.gradle.kts

@@ -10,7 +10,7 @@ android {
 
     defaultConfig {
         applicationId = "com.github.google.bumble.btbench"
-        minSdk = 30
+        minSdk = 33
         targetSdk = 34
         versionCode = 1
         versionName = "1.0"

extras/android/BtBench/app/src/main/AndroidManifest.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.github.google.bumble.btbench">
-     <uses-sdk android:minSdkVersion="30" android:targetSdkVersion="34" />
+     <uses-sdk android:minSdkVersion="33" android:targetSdkVersion="34" />
     <!-- Request legacy Bluetooth permissions on older devices. -->
     <uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30" />
     <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" android:maxSdkVersion="30" />
@@ -9,6 +9,8 @@
     <uses-permission android:name="android.permission.BLUETOOTH_SCAN" android:usesPermissionFlags="neverForLocation"/>
     <uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
     <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.INTERNET" />
 
     <uses-feature android:name="android.hardware.bluetooth" android:required="true"/>
     <uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Advertiser.kt

@@ -0,0 +1,39 @@
+package com.github.google.bumble.btbench
+
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.le.AdvertiseCallback
+import android.bluetooth.le.AdvertiseData
+import android.bluetooth.le.AdvertiseSettings
+import android.bluetooth.le.AdvertiseSettings.ADVERTISE_MODE_LOW_LATENCY
+import android.os.Build
+import java.util.logging.Logger
+
+private val Log = Logger.getLogger("btbench.advertiser")
+
+class Advertiser(private val bluetoothAdapter: BluetoothAdapter) : AdvertiseCallback() {
+    @SuppressLint("MissingPermission")
+    fun start() {
+        val advertiseSettingsBuilder = AdvertiseSettings.Builder()
+            .setAdvertiseMode(ADVERTISE_MODE_LOW_LATENCY)
+            .setConnectable(true)
+        advertiseSettingsBuilder.setDiscoverable(true)
+        val advertiseSettings = advertiseSettingsBuilder.build()
+        val advertiseData = AdvertiseData.Builder().build()
+        val scanData = AdvertiseData.Builder().setIncludeDeviceName(true).build()
+        bluetoothAdapter.bluetoothLeAdvertiser.startAdvertising(advertiseSettings, advertiseData, scanData, this)
+    }
+
+    @SuppressLint("MissingPermission")
+    fun stop() {
+        bluetoothAdapter.bluetoothLeAdvertiser.stopAdvertising(this)
+    }
+
+    override fun onStartFailure(errorCode: Int) {
+        Log.warning("failed to start advertising: $errorCode")
+    }
+
+    override fun onStartSuccess(settingsInEffect: AdvertiseSettings) {
+        Log.info("advertising started: $settingsInEffect")
+    }
+}

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/AutomationSnippet.java

@@ -22,11 +22,13 @@ import androidx.test.core.app.ApplicationProvider;
 
 import com.google.android.mobly.snippet.Snippet;
 import com.google.android.mobly.snippet.rpc.Rpc;
+import com.google.android.mobly.snippet.rpc.RpcOptional;
 
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.io.IOException;
 import java.security.InvalidParameterException;
 import java.util.ArrayList;
 import java.util.UUID;
@@ -71,12 +73,15 @@ public class AutomationSnippet implements Snippet {
     private final Context mContext;
     private final ArrayList<Runner> mRunners = new ArrayList<>();
 
-    public AutomationSnippet() {
+    public AutomationSnippet() throws IOException {
         mContext = ApplicationProvider.getApplicationContext();
         BluetoothManager bluetoothManager = mContext.getSystemService(BluetoothManager.class);
         mBluetoothAdapter = bluetoothManager.getAdapter();
         if (mBluetoothAdapter == null) {
-            throw new RuntimeException("bluetooth not supported");
+            throw new IOException("bluetooth not supported");
+        }
+        if (!mBluetoothAdapter.isEnabled()) {
+            throw new IOException("bluetooth not enabled");
         }
     }
 
@@ -85,32 +90,46 @@ public class AutomationSnippet implements Snippet {
         switch (mode) {
             case "rfcomm-client":
                 runnable = new RfcommClient(model, mBluetoothAdapter,
-                                          (PacketIO packetIO) -> createIoClient(model, scenario,
-                                                                                packetIO));
+                                            (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                  packetIO));
                 break;
 
             case "rfcomm-server":
                 runnable = new RfcommServer(model, mBluetoothAdapter,
-                                          (PacketIO packetIO) -> createIoClient(model, scenario,
-                                                                                packetIO));
+                                            (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                  packetIO));
                 break;
 
             case "l2cap-client":
                 runnable = new L2capClient(model, mBluetoothAdapter, mContext,
-                                         (PacketIO packetIO) -> createIoClient(model, scenario,
-                                                                               packetIO));
+                                           (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                 packetIO));
                 break;
 
             case "l2cap-server":
                 runnable = new L2capServer(model, mBluetoothAdapter,
-                                         (PacketIO packetIO) -> createIoClient(model, scenario,
-                                                                               packetIO));
+                                           (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                 packetIO));
+                break;
+
+            case "gatt-client":
+                runnable = new GattClient(model, mBluetoothAdapter, mContext,
+                                          (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                packetIO));
+                break;
+
+            case "gatt-server":
+                runnable = new GattServer(model, mBluetoothAdapter, mContext,
+                                          (PacketIO packetIO) -> createIoClient(model, scenario,
+                                                                                packetIO));
                 break;
 
             default:
                 return null;
         }
 
+        model.setMode(mode);
+        model.setScenario(scenario);
         runnable.run();
         Runner runner = new Runner(runnable, mode, scenario, model);
         mRunners.add(runner);
@@ -140,7 +159,21 @@ public class AutomationSnippet implements Snippet {
         JSONObject result = new JSONObject();
         result.put("status", model.getStatus());
         result.put("running", model.getRunning());
+        result.put("peer_bluetooth_address", model.getPeerBluetoothAddress());
+        result.put("mode", model.getMode());
+        result.put("scenario", model.getScenario());
+        result.put("sender_packet_size", model.getSenderPacketSize());
+        result.put("sender_packet_count", model.getSenderPacketCount());
+        result.put("sender_packet_interval", model.getSenderPacketInterval());
+        result.put("packets_sent", model.getPacketsSent());
+        result.put("packets_received", model.getPacketsReceived());
         result.put("l2cap_psm", model.getL2capPsm());
+        result.put("use_2m_phy", model.getUse2mPhy());
+        result.put("connection_priority", model.getConnectionPriority());
+        result.put("mtu", model.getMtu());
+        result.put("rx_phy", model.getRxPhy());
+        result.put("tx_phy", model.getTxPhy());
+        result.put("startup_delay", model.getStartupDelay());
         if (model.getStatus().equals("OK")) {
             JSONObject stats = new JSONObject();
             result.put("stats", stats);
@@ -167,12 +200,12 @@ public class AutomationSnippet implements Snippet {
 
     @Rpc(description = "Run a scenario in RFComm Client mode")
     public JSONObject runRfcommClient(String scenario, String peerBluetoothAddress, int packetCount,
-                                      int packetSize, int packetInterval) throws JSONException {
-        assert (mBluetoothAdapter != null);
-
+                                      int packetSize, int packetInterval,
+                                      @RpcOptional Integer startupDelay) throws JSONException {
         // We only support "send" and "ping" for this mode for now
         if (!(scenario.equals("send") || scenario.equals("ping"))) {
-            throw new InvalidParameterException("only 'send' and 'ping' are supported for this mode");
+            throw new InvalidParameterException(
+                    "only 'send' and 'ping' are supported for this mode");
         }
 
         AppViewModel model = new AppViewModel();
@@ -180,6 +213,9 @@ public class AutomationSnippet implements Snippet {
         model.setSenderPacketCount(packetCount);
         model.setSenderPacketSize(packetSize);
         model.setSenderPacketInterval(packetInterval);
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
 
         Runner runner = runScenario(model, "rfcomm-client", scenario);
         assert runner != null;
@@ -187,15 +223,18 @@ public class AutomationSnippet implements Snippet {
     }
 
     @Rpc(description = "Run a scenario in RFComm Server mode")
-    public JSONObject runRfcommServer(String scenario) throws JSONException {
-        assert (mBluetoothAdapter != null);
-
+    public JSONObject runRfcommServer(String scenario,
+                                      @RpcOptional Integer startupDelay) throws JSONException {
         // We only support "receive" and "pong" for this mode for now
         if (!(scenario.equals("receive") || scenario.equals("pong"))) {
-            throw new InvalidParameterException("only 'receive' and 'pong' are supported for this mode");
+            throw new InvalidParameterException(
+                    "only 'receive' and 'pong' are supported for this mode");
         }
 
         AppViewModel model = new AppViewModel();
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
 
         Runner runner = runScenario(model, "rfcomm-server", scenario);
         assert runner != null;
@@ -205,12 +244,12 @@ public class AutomationSnippet implements Snippet {
     @Rpc(description = "Run a scenario in L2CAP Client mode")
     public JSONObject runL2capClient(String scenario, String peerBluetoothAddress, int psm,
                                      boolean use_2m_phy, int packetCount, int packetSize,
-                                     int packetInterval) throws JSONException {
-        assert (mBluetoothAdapter != null);
-
+                                     int packetInterval, @RpcOptional String connectionPriority,
+                                     @RpcOptional Integer startupDelay) throws JSONException {
         // We only support "send" and "ping" for this mode for now
         if (!(scenario.equals("send") || scenario.equals("ping"))) {
-            throw new InvalidParameterException("only 'send' and 'ping' are supported for this mode");
+            throw new InvalidParameterException(
+                    "only 'send' and 'ping' are supported for this mode");
         }
 
         AppViewModel model = new AppViewModel();
@@ -220,28 +259,83 @@ public class AutomationSnippet implements Snippet {
         model.setSenderPacketCount(packetCount);
         model.setSenderPacketSize(packetSize);
         model.setSenderPacketInterval(packetInterval);
-
+        if (connectionPriority != null) {
+            model.setConnectionPriority(connectionPriority);
+        }
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
         Runner runner = runScenario(model, "l2cap-client", scenario);
         assert runner != null;
         return runner.toJson();
     }
 
     @Rpc(description = "Run a scenario in L2CAP Server mode")
-    public JSONObject runL2capServer(String scenario) throws JSONException {
-        assert (mBluetoothAdapter != null);
-
+    public JSONObject runL2capServer(String scenario,
+                                     @RpcOptional Integer startupDelay) throws JSONException {
         // We only support "receive" and "pong" for this mode for now
         if (!(scenario.equals("receive") || scenario.equals("pong"))) {
-            throw new InvalidParameterException("only 'receive' and 'pong' are supported for this mode");
+            throw new InvalidParameterException(
+                    "only 'receive' and 'pong' are supported for this mode");
         }
 
         AppViewModel model = new AppViewModel();
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
 
         Runner runner = runScenario(model, "l2cap-server", scenario);
         assert runner != null;
         return runner.toJson();
     }
 
+    @Rpc(description = "Run a scenario in GATT Client mode")
+    public JSONObject runGattClient(String scenario, String peerBluetoothAddress,
+                                    boolean use_2m_phy, int packetCount, int packetSize,
+                                    int packetInterval, @RpcOptional String connectionPriority,
+                                    @RpcOptional Integer startupDelay) throws JSONException {
+        // We only support "send" and "ping" for this mode for now
+        if (!(scenario.equals("send") || scenario.equals("ping"))) {
+            throw new InvalidParameterException(
+                    "only 'send' and 'ping' are supported for this mode");
+        }
+
+        AppViewModel model = new AppViewModel();
+        model.setPeerBluetoothAddress(peerBluetoothAddress);
+        model.setUse2mPhy(use_2m_phy);
+        model.setSenderPacketCount(packetCount);
+        model.setSenderPacketSize(packetSize);
+        model.setSenderPacketInterval(packetInterval);
+        if (connectionPriority != null) {
+            model.setConnectionPriority(connectionPriority);
+        }
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
+        Runner runner = runScenario(model, "gatt-client", scenario);
+        assert runner != null;
+        return runner.toJson();
+    }
+
+    @Rpc(description = "Run a scenario in GATT Server mode")
+    public JSONObject runGattServer(String scenario,
+                                    @RpcOptional Integer startupDelay) throws JSONException {
+        // We only support "receive" and "pong" for this mode for now
+        if (!(scenario.equals("receive") || scenario.equals("pong"))) {
+            throw new InvalidParameterException(
+                    "only 'receive' and 'pong' are supported for this mode");
+        }
+
+        AppViewModel model = new AppViewModel();
+        if (startupDelay != null) {
+            model.setStartupDelay(startupDelay);
+        }
+
+        Runner runner = runScenario(model, "gatt-server", scenario);
+        assert runner != null;
+        return runner.toJson();
+    }
+
     @Rpc(description = "Stop a Runner")
     public JSONObject stopRunner(String runnerId) throws JSONException {
         Runner runner = findRunner(runnerId);
@@ -276,7 +370,7 @@ public class AutomationSnippet implements Snippet {
         JSONObject result = new JSONObject();
         JSONArray runners = new JSONArray();
         result.put("runners", runners);
-        for (Runner runner: mRunners) {
+        for (Runner runner : mRunners) {
             runners.put(runner.toJson());
         }
 

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Connection.kt

@@ -0,0 +1,109 @@
+package com.github.google.bumble.btbench
+
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothDevice
+import android.bluetooth.BluetoothGatt
+import android.bluetooth.BluetoothGattCallback
+import android.bluetooth.BluetoothManager
+import android.bluetooth.BluetoothProfile
+import android.content.Context
+import android.os.Build
+import androidx.core.content.ContextCompat
+import java.util.logging.Logger
+
+private val Log = Logger.getLogger("btbench.connection")
+
+open class Connection(
+    private val viewModel: AppViewModel,
+    private val bluetoothAdapter: BluetoothAdapter,
+    private val context: Context
+) : BluetoothGattCallback() {
+    var remoteDevice: BluetoothDevice? = null
+    var gatt: BluetoothGatt? = null
+
+    @SuppressLint("MissingPermission")
+    open fun connect() {
+        val addressIsPublic = viewModel.peerBluetoothAddress.endsWith("/P")
+        val address = viewModel.peerBluetoothAddress.take(17)
+        remoteDevice = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            bluetoothAdapter.getRemoteLeDevice(
+                address,
+                if (addressIsPublic) {
+                    BluetoothDevice.ADDRESS_TYPE_PUBLIC
+                } else {
+                    BluetoothDevice.ADDRESS_TYPE_RANDOM
+                }
+            )
+        } else {
+            bluetoothAdapter.getRemoteDevice(address)
+        }
+
+        gatt = remoteDevice?.connectGatt(
+            context,
+            false,
+            this,
+            BluetoothDevice.TRANSPORT_LE,
+            if (viewModel.use2mPhy) BluetoothDevice.PHY_LE_2M_MASK else BluetoothDevice.PHY_LE_1M_MASK
+        )
+    }
+
+    @SuppressLint("MissingPermission")
+    open fun disconnect() {
+        gatt?.disconnect()
+    }
+
+    override fun onMtuChanged(gatt: BluetoothGatt, mtu: Int, status: Int) {
+        Log.info("MTU update: mtu=$mtu status=$status")
+        viewModel.mtu = mtu
+    }
+
+    override fun onPhyUpdate(gatt: BluetoothGatt, txPhy: Int, rxPhy: Int, status: Int) {
+        Log.info("PHY update: tx=$txPhy, rx=$rxPhy, status=$status")
+        viewModel.txPhy = txPhy
+        viewModel.rxPhy = rxPhy
+    }
+
+    override fun onPhyRead(gatt: BluetoothGatt, txPhy: Int, rxPhy: Int, status: Int) {
+        Log.info("PHY: tx=$txPhy, rx=$rxPhy, status=$status")
+        viewModel.txPhy = txPhy
+        viewModel.rxPhy = rxPhy
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun onConnectionStateChange(
+        gatt: BluetoothGatt?, status: Int, newState: Int
+    ) {
+        if (status != BluetoothGatt.GATT_SUCCESS) {
+            Log.warning("onConnectionStateChange status=$status")
+        }
+
+        if (gatt != null && newState == BluetoothProfile.STATE_CONNECTED) {
+            if (viewModel.use2mPhy) {
+                Log.info("requesting 2M PHY")
+                gatt.setPreferredPhy(
+                    BluetoothDevice.PHY_LE_2M_MASK,
+                    BluetoothDevice.PHY_LE_2M_MASK,
+                    BluetoothDevice.PHY_OPTION_NO_PREFERRED
+                )
+            }
+            gatt.readPhy()
+
+            // Request an MTU update, even though we don't use GATT, because Android
+            // won't request a larger link layer maximum data length otherwise.
+            gatt.requestMtu(517)
+
+            // Request a specific connection priority
+            val connectionPriority = when (viewModel.connectionPriority) {
+                "BALANCED" -> BluetoothGatt.CONNECTION_PRIORITY_BALANCED
+                "LOW_POWER" -> BluetoothGatt.CONNECTION_PRIORITY_LOW_POWER
+                "HIGH" -> BluetoothGatt.CONNECTION_PRIORITY_HIGH
+                "DCK" -> BluetoothGatt.CONNECTION_PRIORITY_DCK
+                else -> 0
+            }
+            if (!gatt.requestConnectionPriority(connectionPriority)) {
+                Log.warning("requestConnectionPriority failed")
+            }
+        }
+    }
+}

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Gatt.kt

@@ -0,0 +1,23 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.github.google.bumble.btbench
+
+import java.util.UUID
+
+var CCCD_UUID = UUID.fromString("00002902-0000-1000-8000-00805F9B34FB")
+
+val BENCH_SERVICE_UUID = UUID.fromString("50DB505C-8AC4-4738-8448-3B1D9CC09CC5")
+val BENCH_TX_UUID = UUID.fromString("E789C754-41A1-45F4-A948-A0A1A90DBA53")
+val BENCH_RX_UUID = UUID.fromString("016A2CC7-E14B-4819-935F-1F56EAE4098D")

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/GattClient.kt

@@ -0,0 +1,224 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.github.google.bumble.btbench
+
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothGatt
+import android.bluetooth.BluetoothGattCharacteristic
+import android.bluetooth.BluetoothGattDescriptor
+import android.bluetooth.BluetoothProfile
+import android.content.Context
+import java.io.IOException
+import java.util.UUID
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.Semaphore
+import java.util.logging.Logger
+import kotlin.concurrent.thread
+
+private val Log = Logger.getLogger("btbench.gatt-client")
+
+
+class GattClientConnection(
+    viewModel: AppViewModel,
+    bluetoothAdapter: BluetoothAdapter,
+    context: Context
+) : Connection(viewModel, bluetoothAdapter, context), PacketIO {
+    override var packetSink: PacketSink? = null
+    private val discoveryDone: CountDownLatch = CountDownLatch(1)
+    private val writeSemaphore: Semaphore = Semaphore(1)
+    var rxCharacteristic: BluetoothGattCharacteristic? = null
+    var txCharacteristic: BluetoothGattCharacteristic? = null
+
+    override fun connect() {
+        super.connect()
+
+        // Check if we're already connected and have discovered the services
+        if (gatt?.getService(BENCH_SERVICE_UUID) != null) {
+            Log.fine("already connected")
+            onServicesDiscovered(gatt, BluetoothGatt.GATT_SUCCESS)
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun onConnectionStateChange(
+        gatt: BluetoothGatt?, status: Int, newState: Int
+    ) {
+        super.onConnectionStateChange(gatt, status, newState)
+        if (status != BluetoothGatt.GATT_SUCCESS) {
+            Log.warning("onConnectionStateChange status=$status")
+            discoveryDone.countDown()
+            return
+        }
+        if (gatt != null && newState == BluetoothProfile.STATE_CONNECTED) {
+            if (!gatt.discoverServices()) {
+                Log.warning("discoverServices could not start")
+                discoveryDone.countDown()
+            }
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun onServicesDiscovered(gatt: BluetoothGatt?, status: Int) {
+        Log.fine("onServicesDiscovered")
+
+        if (status != BluetoothGatt.GATT_SUCCESS) {
+            Log.warning("failed to discover services: ${status}")
+            discoveryDone.countDown()
+            return
+        }
+
+        // Find the service
+        val service = gatt!!.getService(BENCH_SERVICE_UUID)
+        if (service == null) {
+            Log.warning("GATT Service not found")
+            discoveryDone.countDown()
+            return
+        }
+
+        // Find the RX and TX characteristics
+        rxCharacteristic = service.getCharacteristic(BENCH_RX_UUID)
+        if (rxCharacteristic == null) {
+            Log.warning("GATT RX Characteristics not found")
+            discoveryDone.countDown()
+            return
+        }
+        txCharacteristic = service.getCharacteristic(BENCH_TX_UUID)
+        if (txCharacteristic == null) {
+            Log.warning("GATT TX Characteristics not found")
+            discoveryDone.countDown()
+            return
+        }
+
+        // Subscribe to the RX characteristic
+        Log.fine("subscribing to RX")
+        gatt.setCharacteristicNotification(rxCharacteristic, true)
+        val cccdDescriptor = rxCharacteristic!!.getDescriptor(CCCD_UUID)
+        gatt.writeDescriptor(cccdDescriptor, BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
+
+        Log.info("GATT discovery complete")
+        discoveryDone.countDown()
+    }
+
+    override fun onCharacteristicWrite(
+        gatt: BluetoothGatt?,
+        characteristic: BluetoothGattCharacteristic?,
+        status: Int
+    ) {
+        // Now we can write again
+        writeSemaphore.release()
+
+        if (status != BluetoothGatt.GATT_SUCCESS) {
+            Log.warning("onCharacteristicWrite failed: $status")
+            return
+        }
+    }
+
+    override fun onCharacteristicChanged(
+        gatt: BluetoothGatt,
+        characteristic: BluetoothGattCharacteristic,
+        value: ByteArray
+    ) {
+        if (characteristic.uuid == BENCH_RX_UUID && packetSink != null) {
+            val packet = Packet.from(value)
+            packetSink!!.onPacket(packet)
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun sendPacket(packet: Packet) {
+        if (txCharacteristic == null) {
+            Log.warning("No TX characteristic, dropping")
+            return
+        }
+
+        // Wait until we can write
+        writeSemaphore.acquire()
+
+        // Write the data
+        val data = packet.toBytes()
+        val clampedData = if (data.size > 512) {
+            // Clamp the data to the maximum allowed characteristic data size
+            data.copyOf(512)
+        } else {
+            data
+        }
+        gatt?.writeCharacteristic(
+            txCharacteristic!!,
+            clampedData,
+            BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE
+        )
+    }
+
+    override
+    fun disconnect() {
+        super.disconnect()
+        discoveryDone.countDown()
+    }
+
+    fun waitForDiscoveryCompletion() {
+        discoveryDone.await()
+    }
+}
+
+class GattClient(
+    private val viewModel: AppViewModel,
+    bluetoothAdapter: BluetoothAdapter,
+    context: Context,
+    private val createIoClient: (packetIo: PacketIO) -> IoClient
+) : Mode {
+    private var connection: GattClientConnection =
+        GattClientConnection(viewModel, bluetoothAdapter, context)
+    private var clientThread: Thread? = null
+
+    @SuppressLint("MissingPermission")
+    override fun run() {
+        viewModel.running = true
+
+        clientThread = thread(name = "GattClient") {
+            connection.connect()
+
+            viewModel.aborter = {
+                connection.disconnect()
+            }
+
+            // Discover the rx and tx characteristics
+            connection.waitForDiscoveryCompletion()
+            if (connection.rxCharacteristic == null || connection.txCharacteristic == null) {
+                connection.disconnect()
+                viewModel.running = false
+                return@thread
+            }
+
+            val ioClient = createIoClient(connection)
+
+            try {
+                ioClient.run()
+                viewModel.status = "OK"
+            } catch (error: IOException) {
+                Log.info("run ended abruptly")
+                viewModel.status = "ABORTED"
+                viewModel.lastError = "IO_ERROR"
+            } finally {
+                connection.disconnect()
+                viewModel.running = false
+            }
+        }
+    }
+
+    override fun waitForCompletion() {
+        clientThread?.join()
+    }
+}

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/GattServer.kt

@@ -0,0 +1,243 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.github.google.bumble.btbench
+
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothDevice
+import android.bluetooth.BluetoothGatt
+import android.bluetooth.BluetoothGattCharacteristic
+import android.bluetooth.BluetoothGattDescriptor
+import android.bluetooth.BluetoothGattServer
+import android.bluetooth.BluetoothGattServerCallback
+import android.bluetooth.BluetoothGattService
+import android.bluetooth.BluetoothManager
+import android.bluetooth.BluetoothStatusCodes
+import android.content.Context
+import androidx.core.content.ContextCompat
+import java.io.IOException
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.LinkedBlockingQueue
+import java.util.concurrent.Semaphore
+import java.util.logging.Logger
+import kotlin.concurrent.thread
+import kotlin.experimental.and
+
+private val Log = Logger.getLogger("btbench.gatt-server")
+
+@SuppressLint("MissingPermission")
+class GattServer(
+    private val viewModel: AppViewModel,
+    private val bluetoothAdapter: BluetoothAdapter,
+    context: Context,
+    private val createIoClient: (packetIo: PacketIO) -> IoClient
+) : Mode, PacketIO, BluetoothGattServerCallback() {
+    override var packetSink: PacketSink? = null
+    private val gattServer: BluetoothGattServer
+    private val rxCharacteristic: BluetoothGattCharacteristic?
+    private val txCharacteristic: BluetoothGattCharacteristic?
+    private val notifySemaphore: Semaphore = Semaphore(1)
+    private val ready: CountDownLatch = CountDownLatch(1)
+    private var peerDevice: BluetoothDevice? = null
+    private var clientThread: Thread? = null
+    private var sinkQueue: LinkedBlockingQueue<Packet>? = null
+
+    init {
+        val bluetoothManager = ContextCompat.getSystemService(context, BluetoothManager::class.java)
+        gattServer = bluetoothManager!!.openGattServer(context, this)
+        val benchService = gattServer.getService(BENCH_SERVICE_UUID)
+        if (benchService == null) {
+            rxCharacteristic = BluetoothGattCharacteristic(
+                BENCH_RX_UUID,
+                BluetoothGattCharacteristic.PROPERTY_NOTIFY,
+                0
+            )
+            txCharacteristic = BluetoothGattCharacteristic(
+                BENCH_TX_UUID,
+                BluetoothGattCharacteristic.PROPERTY_WRITE_NO_RESPONSE,
+                BluetoothGattCharacteristic.PERMISSION_WRITE
+            )
+            val rxCCCD = BluetoothGattDescriptor(
+                CCCD_UUID,
+                BluetoothGattDescriptor.PERMISSION_READ or BluetoothGattDescriptor.PERMISSION_WRITE
+            )
+            rxCharacteristic.addDescriptor(rxCCCD)
+
+            val service =
+                BluetoothGattService(BENCH_SERVICE_UUID, BluetoothGattService.SERVICE_TYPE_PRIMARY)
+            service.addCharacteristic(rxCharacteristic)
+            service.addCharacteristic(txCharacteristic)
+
+            gattServer.addService(service)
+        } else {
+            rxCharacteristic = benchService.getCharacteristic(BENCH_RX_UUID)
+            txCharacteristic = benchService.getCharacteristic(BENCH_TX_UUID)
+        }
+    }
+
+    override fun onCharacteristicWriteRequest(
+        device: BluetoothDevice?,
+        requestId: Int,
+        characteristic: BluetoothGattCharacteristic?,
+        preparedWrite: Boolean,
+        responseNeeded: Boolean,
+        offset: Int,
+        value: ByteArray?
+    ) {
+        Log.info("onCharacteristicWriteRequest")
+        if (characteristic != null && characteristic.uuid == BENCH_TX_UUID) {
+            if (packetSink == null) {
+                Log.warning("no sink, dropping")
+            } else if (offset != 0) {
+                Log.warning("offset != 0")
+            } else if (value == null) {
+                Log.warning("no value")
+            } else {
+                // Deliver the packet in a separate thread so that we don't block this
+                // callback.
+                sinkQueue?.put(Packet.from(value))
+            }
+        }
+
+        if (responseNeeded) {
+            gattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, value)
+        }
+    }
+
+    override fun onNotificationSent(device: BluetoothDevice?, status: Int) {
+        if (status == BluetoothGatt.GATT_SUCCESS) {
+            notifySemaphore.release()
+        }
+    }
+
+    override fun onDescriptorWriteRequest(
+        device: BluetoothDevice?,
+        requestId: Int,
+        descriptor: BluetoothGattDescriptor?,
+        preparedWrite: Boolean,
+        responseNeeded: Boolean,
+        offset: Int,
+        value: ByteArray?
+    ) {
+        if (descriptor?.uuid == CCCD_UUID && descriptor?.characteristic?.uuid == BENCH_RX_UUID) {
+            if (offset == 0 && value?.size == 2) {
+                if (value[0].and(1).toInt() != 0) {
+                    // Subscription
+                    Log.fine("peer subscribed to RX")
+                    peerDevice = device
+                    ready.countDown()
+                }
+            }
+        }
+
+        if (responseNeeded) {
+            gattServer.sendResponse(device, requestId, BluetoothGatt.GATT_SUCCESS, offset, value)
+        }
+    }
+
+    @SuppressLint("MissingPermission")
+    override fun sendPacket(packet: Packet) {
+        if (peerDevice == null) {
+            Log.warning("no peer device, cannot send")
+            return
+        }
+        if (rxCharacteristic == null) {
+            Log.warning("no RX characteristic, cannot send")
+            return
+        }
+
+        // Wait until we can notify
+        notifySemaphore.acquire()
+
+        // Send the packet via a notification
+        val result = gattServer.notifyCharacteristicChanged(
+            peerDevice!!,
+            rxCharacteristic,
+            false,
+            packet.toBytes()
+        )
+        if (result != BluetoothStatusCodes.SUCCESS) {
+            Log.warning("notifyCharacteristicChanged failed: $result")
+            notifySemaphore.release()
+        }
+    }
+
+    override fun run() {
+        viewModel.running = true
+
+        // Start advertising
+        Log.fine("starting advertiser")
+        val advertiser = Advertiser(bluetoothAdapter)
+        advertiser.start()
+
+        clientThread = thread(name = "GattServer") {
+            // Wait for a subscriber
+            Log.info("waiting for RX subscriber")
+            viewModel.aborter = {
+                ready.countDown()
+            }
+            ready.await()
+            if (peerDevice == null) {
+                Log.warning("server interrupted")
+                viewModel.running = false
+                gattServer.close()
+                return@thread
+            }
+            Log.info("RX subscriber accepted")
+
+            // Stop advertising
+            Log.info("stopping advertiser")
+            advertiser.stop()
+
+            sinkQueue = LinkedBlockingQueue()
+            val sinkWriterThread = thread(name = "SinkWriter") {
+                while (true) {
+                    try {
+                        val packet = sinkQueue!!.take()
+                        if (packetSink == null) {
+                            Log.warning("no sink, dropping packet")
+                            continue
+                        }
+                        packetSink!!.onPacket(packet)
+                    } catch (error: InterruptedException) {
+                        Log.warning("sink writer interrupted")
+                        break
+                    }
+                }
+            }
+
+            val ioClient = createIoClient(this)
+
+            try {
+                ioClient.run()
+                viewModel.status = "OK"
+            } catch (error: IOException) {
+                Log.info("run ended abruptly")
+                viewModel.status = "ABORTED"
+                viewModel.lastError = "IO_ERROR"
+            } finally {
+                sinkWriterThread.interrupt()
+                sinkWriterThread.join()
+                gattServer.close()
+                viewModel.running = false
+            }
+        }
+    }
+
+    override fun waitForCompletion() {
+        clientThread?.join()
+        Log.info("server thread completed")
+    }
+}

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capClient.kt

@@ -16,89 +16,25 @@ package com.github.google.bumble.btbench
 
 import android.annotation.SuppressLint
 import android.bluetooth.BluetoothAdapter
-import android.bluetooth.BluetoothDevice
-import android.bluetooth.BluetoothGatt
-import android.bluetooth.BluetoothGattCallback
-import android.bluetooth.BluetoothProfile
 import android.content.Context
-import android.os.Build
 import java.util.logging.Logger
 
 private val Log = Logger.getLogger("btbench.l2cap-client")
 
 class L2capClient(
     private val viewModel: AppViewModel,
-    private val bluetoothAdapter: BluetoothAdapter,
-    private val context: Context,
+    bluetoothAdapter: BluetoothAdapter,
+    context: Context,
     private val createIoClient: (packetIo: PacketIO) -> IoClient
 ) : Mode {
+    private var connection: Connection = Connection(viewModel, bluetoothAdapter, context)
     private var socketClient: SocketClient? = null
 
     @SuppressLint("MissingPermission")
     override fun run() {
         viewModel.running = true
-        val addressIsPublic = viewModel.peerBluetoothAddress.endsWith("/P")
-        val address = viewModel.peerBluetoothAddress.take(17)
-        val remoteDevice = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
-            bluetoothAdapter.getRemoteLeDevice(
-                address,
-                if (addressIsPublic) {
-                    BluetoothDevice.ADDRESS_TYPE_PUBLIC
-                } else {
-                    BluetoothDevice.ADDRESS_TYPE_RANDOM
-                }
-            )
-        } else {
-            bluetoothAdapter.getRemoteDevice(address)
-        }
-
-        val gatt = remoteDevice.connectGatt(
-            context,
-            false,
-            object : BluetoothGattCallback() {
-                override fun onMtuChanged(gatt: BluetoothGatt, mtu: Int, status: Int) {
-                    Log.info("MTU update: mtu=$mtu status=$status")
-                    viewModel.mtu = mtu
-                }
-
-                override fun onPhyUpdate(gatt: BluetoothGatt, txPhy: Int, rxPhy: Int, status: Int) {
-                    Log.info("PHY update: tx=$txPhy, rx=$rxPhy, status=$status")
-                    viewModel.txPhy = txPhy
-                    viewModel.rxPhy = rxPhy
-                }
-
-                override fun onPhyRead(gatt: BluetoothGatt, txPhy: Int, rxPhy: Int, status: Int) {
-                    Log.info("PHY: tx=$txPhy, rx=$rxPhy, status=$status")
-                    viewModel.txPhy = txPhy
-                    viewModel.rxPhy = rxPhy
-                }
-
-                override fun onConnectionStateChange(
-                    gatt: BluetoothGatt?, status: Int, newState: Int
-                ) {
-                    if (gatt != null && newState == BluetoothProfile.STATE_CONNECTED) {
-                        if (viewModel.use2mPhy) {
-                            Log.info("requesting 2M PHY")
-                            gatt.setPreferredPhy(
-                                BluetoothDevice.PHY_LE_2M_MASK,
-                                BluetoothDevice.PHY_LE_2M_MASK,
-                                BluetoothDevice.PHY_OPTION_NO_PREFERRED
-                            )
-                        }
-                        gatt.readPhy()
-
-                        // Request an MTU update, even though we don't use GATT, because Android
-                        // won't request a larger link layer maximum data length otherwise.
-                        gatt.requestMtu(517)
-                    }
-                }
-            },
-            BluetoothDevice.TRANSPORT_LE,
-            if (viewModel.use2mPhy) BluetoothDevice.PHY_LE_2M_MASK else BluetoothDevice.PHY_LE_1M_MASK
-        )
-
-        val socket = remoteDevice.createInsecureL2capChannel(viewModel.l2capPsm)
-
+        connection.connect()
+        val socket = connection.remoteDevice!!.createInsecureL2capChannel(viewModel.l2capPsm)
         socketClient = SocketClient(viewModel, socket, createIoClient)
         socketClient!!.run()
     }

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/L2capServer.kt

@@ -37,34 +37,15 @@ class L2capServer(
     @SuppressLint("MissingPermission")
     override fun run() {
         // Advertise so that the peer can find us and connect.
-        val callback = object : AdvertiseCallback() {
-            override fun onStartFailure(errorCode: Int) {
-                Log.warning("failed to start advertising: $errorCode")
-            }
-
-            override fun onStartSuccess(settingsInEffect: AdvertiseSettings) {
-                Log.info("advertising started: $settingsInEffect")
-            }
-        }
-        val advertiseSettingsBuilder = AdvertiseSettings.Builder()
-            .setAdvertiseMode(ADVERTISE_MODE_LOW_LATENCY)
-            .setConnectable(true)
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
-            advertiseSettingsBuilder.setDiscoverable(true)
-        }
-        val advertiseSettings = advertiseSettingsBuilder.build()
-        val advertiseData = AdvertiseData.Builder().build()
-        val scanData = AdvertiseData.Builder().setIncludeDeviceName(true).build()
-        val advertiser = bluetoothAdapter.bluetoothLeAdvertiser
-
+        val advertiser = Advertiser(bluetoothAdapter)
         val serverSocket = bluetoothAdapter.listenUsingInsecureL2capChannel()
         viewModel.l2capPsm = serverSocket.psm
         Log.info("psm = $serverSocket.psm")
 
         socketServer = SocketServer(viewModel, serverSocket, createIoClient)
         socketServer!!.run(
-            { advertiser.stopAdvertising(callback) },
-            { advertiser.startAdvertising(advertiseSettings, advertiseData, scanData, callback) }
+            { advertiser.stop() },
+            { advertiser.start() }
         )
     }
 

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/MainActivity.kt

@@ -17,9 +17,12 @@ package com.github.google.bumble.btbench
 import android.Manifest
 import android.annotation.SuppressLint
 import android.bluetooth.BluetoothAdapter
+import android.bluetooth.BluetoothDevice
 import android.bluetooth.BluetoothManager
+import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
+import android.content.IntentFilter
 import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
@@ -66,6 +69,7 @@ import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.core.content.ContextCompat
 import com.github.google.bumble.btbench.ui.theme.BTBenchTheme
+import java.io.IOException
 import java.util.logging.Logger
 
 private val Log = Logger.getLogger("bumble.main-activity")
@@ -76,6 +80,7 @@ const val SENDER_PACKET_SIZE_PREF_KEY = "sender_packet_size"
 const val SENDER_PACKET_INTERVAL_PREF_KEY = "sender_packet_interval"
 const val SCENARIO_PREF_KEY = "scenario"
 const val MODE_PREF_KEY = "mode"
+const val CONNECTION_PRIORITY_PREF_KEY = "connection_priority"
 
 class MainActivity : ComponentActivity() {
     private val appViewModel = AppViewModel()
@@ -84,6 +89,47 @@ class MainActivity : ComponentActivity() {
         super.onCreate(savedInstanceState)
         appViewModel.loadPreferences(getPreferences(Context.MODE_PRIVATE))
         checkPermissions()
+        registerReceivers()
+    }
+
+    private fun registerReceivers() {
+        val pairingRequestIntentFilter = IntentFilter(BluetoothDevice.ACTION_PAIRING_REQUEST)
+        registerReceiver(object: BroadcastReceiver() {
+            @SuppressLint("MissingPermission")
+            override fun onReceive(context: Context, intent: Intent) {
+                Log.info("ACTION_PAIRING_REQUEST")
+                val extras = intent.extras
+                if (extras != null) {
+                    for (key in extras.keySet()) {
+                        Log.info("$key: ${extras.get(key)}")
+                    }
+                }
+                val device: BluetoothDevice? = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE)
+                if (device != null) {
+                    if (checkSelfPermission(Manifest.permission.BLUETOOTH_PRIVILEGED) == PackageManager.PERMISSION_GRANTED) {
+                        Log.info("confirming pairing")
+                        device.setPairingConfirmation(true)
+                    } else {
+                        Log.info("we don't have BLUETOOTH_PRIVILEGED, not confirming")
+                    }
+                }
+
+            }
+        }, pairingRequestIntentFilter)
+
+        val bondStateChangedIntentFilter = IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED)
+        registerReceiver(object: BroadcastReceiver() {
+            @SuppressLint("MissingPermission")
+            override fun onReceive(context: Context, intent: Intent) {
+                Log.info("ACTION_BOND_STATE_CHANGED")
+                val extras = intent.extras
+                if (extras != null) {
+                    for (key in extras.keySet()) {
+                        Log.info("$key: ${extras.get(key)}")
+                    }
+                }
+            }
+        }, bondStateChangedIntentFilter)
     }
 
     private fun checkPermissions() {
@@ -144,9 +190,7 @@ class MainActivity : ComponentActivity() {
         initBluetooth()
         setContent {
             MainView(
-                appViewModel,
-                ::becomeDiscoverable,
-                ::runScenario
+                appViewModel, ::becomeDiscoverable, ::runScenario
             )
         }
 
@@ -182,6 +226,8 @@ class MainActivity : ComponentActivity() {
                 "rfcomm-server" -> appViewModel.mode = RFCOMM_SERVER_MODE
                 "l2cap-client" -> appViewModel.mode = L2CAP_CLIENT_MODE
                 "l2cap-server" -> appViewModel.mode = L2CAP_SERVER_MODE
+                "gatt-client" -> appViewModel.mode = GATT_CLIENT_MODE
+                "gatt-server" -> appViewModel.mode = GATT_SERVER_MODE
             }
         }
         intent.getStringExtra("autostart")?.let {
@@ -195,19 +241,24 @@ class MainActivity : ComponentActivity() {
 
     private fun runScenario() {
         if (bluetoothAdapter == null) {
-            return
+            throw IOException("bluetooth not enabled")
         }
 
         val runner = when (appViewModel.mode) {
             RFCOMM_CLIENT_MODE -> RfcommClient(appViewModel, bluetoothAdapter!!, ::createIoClient)
             RFCOMM_SERVER_MODE -> RfcommServer(appViewModel, bluetoothAdapter!!, ::createIoClient)
             L2CAP_CLIENT_MODE -> L2capClient(
-                appViewModel,
-                bluetoothAdapter!!,
-                baseContext,
-                ::createIoClient
+                appViewModel, bluetoothAdapter!!, baseContext, ::createIoClient
             )
+
             L2CAP_SERVER_MODE -> L2capServer(appViewModel, bluetoothAdapter!!, ::createIoClient)
+            GATT_CLIENT_MODE -> GattClient(
+                appViewModel, bluetoothAdapter!!, baseContext, ::createIoClient
+            )
+            GATT_SERVER_MODE -> GattServer(
+                appViewModel, bluetoothAdapter!!, baseContext, ::createIoClient
+            )
+
             else -> throw IllegalStateException()
         }
         runner.run()
@@ -281,7 +332,7 @@ fun MainView(
                         keyboardController?.hide()
                         focusManager.clearFocus()
                     }),
-                    enabled = (appViewModel.mode == RFCOMM_CLIENT_MODE) or (appViewModel.mode == L2CAP_CLIENT_MODE)
+                    enabled = (appViewModel.mode == RFCOMM_CLIENT_MODE || appViewModel.mode == L2CAP_CLIENT_MODE || appViewModel.mode == GATT_CLIENT_MODE)
                 )
                 Divider()
                 TextField(
@@ -349,24 +400,45 @@ fun MainView(
                         keyboardController?.hide()
                         focusManager.clearFocus()
                     }),
-                    enabled = (appViewModel.scenario == PING_SCENARIO)
+                    enabled = (appViewModel.scenario == PING_SCENARIO || appViewModel.scenario == SEND_SCENARIO)
                 )
                 Divider()
-                ActionButton(
-                    text = "Become Discoverable", onClick = becomeDiscoverable, true
-                )
                 Row(
                     horizontalArrangement = Arrangement.SpaceBetween,
                     verticalAlignment = Alignment.CenterVertically
                 ) {
                     Text(text = "2M PHY")
                     Spacer(modifier = Modifier.padding(start = 8.dp))
-                    Switch(
-                        enabled = (appViewModel.mode == L2CAP_CLIENT_MODE || appViewModel.mode == L2CAP_SERVER_MODE),
+                    Switch(enabled = (appViewModel.mode == L2CAP_CLIENT_MODE || appViewModel.mode == L2CAP_SERVER_MODE || appViewModel.mode == GATT_CLIENT_MODE || appViewModel.mode == GATT_SERVER_MODE),
                         checked = appViewModel.use2mPhy,
-                        onCheckedChange = { appViewModel.use2mPhy = it }
-                    )
-
+                        onCheckedChange = { appViewModel.use2mPhy = it })
+                    Column(Modifier.selectableGroup()) {
+                        listOf(
+                            "BALANCED", "LOW", "HIGH", "DCK"
+                        ).forEach { text ->
+                            Row(
+                                Modifier
+                                    .selectable(
+                                        selected = (text == appViewModel.connectionPriority),
+                                        onClick = { appViewModel.updateConnectionPriority(text) },
+                                        role = Role.RadioButton,
+                                    )
+                                    .padding(horizontal = 16.dp),
+                                verticalAlignment = Alignment.CenterVertically
+                            ) {
+                                RadioButton(
+                                    selected = (text == appViewModel.connectionPriority),
+                                    onClick = null,
+                                    enabled = (appViewModel.mode == L2CAP_CLIENT_MODE || appViewModel.mode == L2CAP_SERVER_MODE || appViewModel.mode == GATT_CLIENT_MODE || appViewModel.mode == GATT_SERVER_MODE)
+                                )
+                                Text(
+                                    text = text,
+                                    style = MaterialTheme.typography.bodyLarge,
+                                    modifier = Modifier.padding(start = 16.dp)
+                                )
+                            }
+                        }
+                    }
                 }
                 Row {
                     Column(Modifier.selectableGroup()) {
@@ -374,7 +446,9 @@ fun MainView(
                             RFCOMM_CLIENT_MODE,
                             RFCOMM_SERVER_MODE,
                             L2CAP_CLIENT_MODE,
-                            L2CAP_SERVER_MODE
+                            L2CAP_SERVER_MODE,
+                            GATT_CLIENT_MODE,
+                            GATT_SERVER_MODE
                         ).forEach { text ->
                             Row(
                                 Modifier
@@ -387,8 +461,7 @@ fun MainView(
                                 verticalAlignment = Alignment.CenterVertically
                             ) {
                                 RadioButton(
-                                    selected = (text == appViewModel.mode),
-                                    onClick = null
+                                    selected = (text == appViewModel.mode), onClick = null
                                 )
                                 Text(
                                     text = text,
@@ -400,10 +473,7 @@ fun MainView(
                     }
                     Column(Modifier.selectableGroup()) {
                         listOf(
-                            SEND_SCENARIO,
-                            RECEIVE_SCENARIO,
-                            PING_SCENARIO,
-                            PONG_SCENARIO
+                            SEND_SCENARIO, RECEIVE_SCENARIO, PING_SCENARIO, PONG_SCENARIO
                         ).forEach { text ->
                             Row(
                                 Modifier
@@ -416,8 +486,7 @@ fun MainView(
                                 verticalAlignment = Alignment.CenterVertically
                             ) {
                                 RadioButton(
-                                    selected = (text == appViewModel.scenario),
-                                    onClick = null
+                                    selected = (text == appViewModel.scenario), onClick = null
                                 )
                                 Text(
                                     text = text,
@@ -435,20 +504,29 @@ fun MainView(
                     ActionButton(
                         text = "Stop", onClick = appViewModel::abort, enabled = appViewModel.running
                     )
+                    ActionButton(
+                        text = "Become Discoverable", onClick = becomeDiscoverable, true
+                    )
                 }
                 Divider()
-                Text(
-                    text = if (appViewModel.mtu != 0) "MTU: ${appViewModel.mtu}" else ""
-                )
-                Text(
-                    text = if (appViewModel.rxPhy != 0 || appViewModel.txPhy != 0) "PHY: tx=${appViewModel.txPhy}, rx=${appViewModel.rxPhy}" else ""
-                )
+                if (appViewModel.mtu != 0) {
+                    Text(
+                        text = "MTU: ${appViewModel.mtu}"
+                    )
+                }
+                if (appViewModel.rxPhy != 0) {
+                    Text(
+                        text = "PHY: tx=${appViewModel.txPhy}, rx=${appViewModel.rxPhy}"
+                    )
+                }
                 Text(
                     text = "Status: ${appViewModel.status}"
                 )
-                Text(
-                    text = "Last Error: ${appViewModel.lastError}"
-                )
+                if (appViewModel.lastError.isNotEmpty()) {
+                    Text(
+                        text = "Last Error: ${appViewModel.lastError}"
+                    )
+                }
                 Text(
                     text = "Packets Sent: ${appViewModel.packetsSent}"
                 )

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Model.kt

@@ -25,6 +25,7 @@ import java.util.UUID
 
 val DEFAULT_RFCOMM_UUID: UUID = UUID.fromString("E6D55659-C8B4-4B85-96BB-B1143AF6D3AE")
 const val DEFAULT_PEER_BLUETOOTH_ADDRESS = "AA:BB:CC:DD:EE:FF"
+const val DEFAULT_STARTUP_DELAY = 3000
 const val DEFAULT_SENDER_PACKET_COUNT = 100
 const val DEFAULT_SENDER_PACKET_SIZE = 1024
 const val DEFAULT_SENDER_PACKET_INTERVAL = 100
@@ -34,6 +35,8 @@ const val L2CAP_CLIENT_MODE = "L2CAP Client"
 const val L2CAP_SERVER_MODE = "L2CAP Server"
 const val RFCOMM_CLIENT_MODE = "RFCOMM Client"
 const val RFCOMM_SERVER_MODE = "RFCOMM Server"
+const val GATT_CLIENT_MODE = "GATT Client"
+const val GATT_SERVER_MODE = "GATT Server"
 
 const val SEND_SCENARIO = "Send"
 const val RECEIVE_SCENARIO = "Receive"
@@ -47,8 +50,10 @@ class AppViewModel : ViewModel() {
     var mode by mutableStateOf(RFCOMM_SERVER_MODE)
     var scenario by mutableStateOf(RECEIVE_SCENARIO)
     var peerBluetoothAddress by mutableStateOf(DEFAULT_PEER_BLUETOOTH_ADDRESS)
+    var startupDelay by mutableIntStateOf(DEFAULT_STARTUP_DELAY)
     var l2capPsm by mutableIntStateOf(DEFAULT_PSM)
     var use2mPhy by mutableStateOf(true)
+    var connectionPriority by mutableStateOf("BALANCED")
     var mtu by mutableIntStateOf(0)
     var rxPhy by mutableIntStateOf(0)
     var txPhy by mutableIntStateOf(0)
@@ -98,6 +103,11 @@ class AppViewModel : ViewModel() {
         if (savedScenario != null) {
             scenario = savedScenario
         }
+
+        val savedConnectionPriority = preferences.getString(CONNECTION_PRIORITY_PREF_KEY, null)
+        if (savedConnectionPriority != null) {
+            connectionPriority = savedConnectionPriority
+        }
     }
 
     fun updatePeerBluetoothAddress(peerBluetoothAddress: String) {
@@ -220,6 +230,14 @@ class AppViewModel : ViewModel() {
         }
     }
 
+    fun updateConnectionPriority(connectionPriority: String) {
+        this.connectionPriority = connectionPriority
+        with(preferences!!.edit()) {
+            putString(CONNECTION_PRIORITY_PREF_KEY, connectionPriority)
+            apply()
+        }
+    }
+
     fun clear() {
         status = ""
         lastError = ""

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Packet.kt

@@ -17,6 +17,7 @@ package com.github.google.bumble.btbench
 import android.bluetooth.BluetoothSocket
 import java.io.IOException
 import java.nio.ByteBuffer
+import java.nio.ByteOrder
 import java.util.logging.Logger
 import kotlin.math.min
 
@@ -37,11 +38,16 @@ abstract class Packet(val type: Int, val payload: ByteArray = ByteArray(0)) {
                 RESET -> ResetPacket()
                 SEQUENCE -> SequencePacket(
                     data[1].toInt(),
-                    ByteBuffer.wrap(data, 2, 4).getInt(),
-                    data.sliceArray(6..<data.size)
+                    ByteBuffer.wrap(data, 2, 4).order(ByteOrder.LITTLE_ENDIAN).getInt(),
+                    ByteBuffer.wrap(data, 6, 4).order(ByteOrder.LITTLE_ENDIAN).getInt(),
+                    data.sliceArray(10..<data.size)
+                )
+
+                ACK -> AckPacket(
+                    data[1].toInt(),
+                    ByteBuffer.wrap(data, 2, 4).order(ByteOrder.LITTLE_ENDIAN).getInt()
                 )
 
-                ACK -> AckPacket(data[1].toInt(), ByteBuffer.wrap(data, 2, 4).getInt())
                 else -> GenericPacket(data[0].toInt(), data.sliceArray(1..<data.size))
             }
         }
@@ -57,16 +63,24 @@ class ResetPacket : Packet(RESET)
 
 class AckPacket(val flags: Int, val sequenceNumber: Int) : Packet(ACK) {
     override fun toBytes(): ByteArray {
-        return ByteBuffer.allocate(1 + 1 + 4).put(type.toByte()).put(flags.toByte())
+        return ByteBuffer.allocate(6).order(
+            ByteOrder.LITTLE_ENDIAN
+        ).put(type.toByte()).put(flags.toByte())
             .putInt(sequenceNumber).array()
     }
 }
 
-class SequencePacket(val flags: Int, val sequenceNumber: Int, payload: ByteArray) :
+class SequencePacket(
+    val flags: Int,
+    val sequenceNumber: Int,
+    val timestamp: Int,
+    payload: ByteArray
+) :
     Packet(SEQUENCE, payload) {
     override fun toBytes(): ByteArray {
-        return ByteBuffer.allocate(1 + 1 + 4 + payload.size).put(type.toByte()).put(flags.toByte())
-            .putInt(sequenceNumber).put(payload).array()
+        return ByteBuffer.allocate(10 + payload.size).order(ByteOrder.LITTLE_ENDIAN)
+            .put(type.toByte()).put(flags.toByte())
+            .putInt(sequenceNumber).putInt(timestamp).put(payload).array()
     }
 }
 

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Pinger.kt

@@ -19,8 +19,6 @@ import java.util.logging.Logger
 import kotlin.time.Duration.Companion.milliseconds
 import kotlin.time.TimeSource
 
-private const val DEFAULT_STARTUP_DELAY = 3000
-
 private val Log = Logger.getLogger("btbench.pinger")
 
 class Pinger(private val viewModel: AppViewModel, private val packetIO: PacketIO) : IoClient,
@@ -36,8 +34,8 @@ class Pinger(private val viewModel: AppViewModel, private val packetIO: PacketIO
     override fun run() {
         viewModel.clear()
 
-        Log.info("startup delay: $DEFAULT_STARTUP_DELAY")
-        Thread.sleep(DEFAULT_STARTUP_DELAY.toLong());
+        Log.info("startup delay: ${viewModel.startupDelay}")
+        Thread.sleep(viewModel.startupDelay.toLong());
         Log.info("running")
 
         Log.info("sending reset")
@@ -48,19 +46,23 @@ class Pinger(private val viewModel: AppViewModel, private val packetIO: PacketIO
 
         val startTime = TimeSource.Monotonic.markNow()
         for (i in 0..<packetCount) {
-            val now = TimeSource.Monotonic.markNow()
-            val targetTime = startTime + (i * viewModel.senderPacketInterval).milliseconds
-            val delay = targetTime - now
-            if (delay.isPositive()) {
-                Log.info("sleeping ${delay.inWholeMilliseconds} ms")
-                Thread.sleep(delay.inWholeMilliseconds)
+            var now = TimeSource.Monotonic.markNow()
+            if (viewModel.senderPacketInterval > 0) {
+                val targetTime = startTime + (i * viewModel.senderPacketInterval).milliseconds
+                val delay = targetTime - now
+                if (delay.isPositive()) {
+                    Log.info("sleeping ${delay.inWholeMilliseconds} ms")
+                    Thread.sleep(delay.inWholeMilliseconds)
+                    now = TimeSource.Monotonic.markNow()
+                }
             }
             pingTimes.add(TimeSource.Monotonic.markNow())
             packetIO.sendPacket(
                 SequencePacket(
                     if (i < packetCount - 1) 0 else Packet.LAST_FLAG,
                     i,
-                    ByteArray(packetSize - 6)
+                    (now - startTime).inWholeMicroseconds.toInt(),
+                    ByteArray(packetSize - 10)
                 )
             )
             viewModel.packetsSent = i + 1

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Ponger.kt

@@ -14,6 +14,7 @@
 
 package com.github.google.bumble.btbench
 
+import java.util.concurrent.CountDownLatch
 import java.util.logging.Logger
 import kotlin.time.TimeSource
 
@@ -23,6 +24,7 @@ class Ponger(private val viewModel: AppViewModel, private val packetIO: PacketIO
     private var startTime: TimeSource.Monotonic.ValueTimeMark = TimeSource.Monotonic.markNow()
     private var lastPacketTime: TimeSource.Monotonic.ValueTimeMark = TimeSource.Monotonic.markNow()
     private var expectedSequenceNumber: Int = 0
+    private val done = CountDownLatch(1)
 
     init {
         packetIO.packetSink = this
@@ -30,6 +32,7 @@ class Ponger(private val viewModel: AppViewModel, private val packetIO: PacketIO
 
     override fun run() {
         viewModel.clear()
+        done.await()
     }
 
     override fun abort() {}
@@ -58,5 +61,10 @@ class Ponger(private val viewModel: AppViewModel, private val packetIO: PacketIO
 
         packetIO.sendPacket(AckPacket(packet.flags, packet.sequenceNumber))
         viewModel.packetsSent += 1
+
+        if (packet.flags and Packet.LAST_FLAG != 0) {
+            Log.info("received last packet")
+            done.countDown()
+        }
     }
 }

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Receiver.kt

@@ -14,6 +14,7 @@
 
 package com.github.google.bumble.btbench
 
+import java.util.concurrent.CountDownLatch
 import java.util.logging.Logger
 import kotlin.time.DurationUnit
 import kotlin.time.TimeSource
@@ -24,6 +25,7 @@ class Receiver(private val viewModel: AppViewModel, private val packetIO: Packet
     private var startTime: TimeSource.Monotonic.ValueTimeMark = TimeSource.Monotonic.markNow()
     private var lastPacketTime: TimeSource.Monotonic.ValueTimeMark = TimeSource.Monotonic.markNow()
     private var bytesReceived = 0
+    private val done = CountDownLatch(1)
 
     init {
         packetIO.packetSink = this
@@ -31,6 +33,7 @@ class Receiver(private val viewModel: AppViewModel, private val packetIO: Packet
 
     override fun run() {
         viewModel.clear()
+        done.await()
     }
 
     override fun abort() {}
@@ -62,6 +65,7 @@ class Receiver(private val viewModel: AppViewModel, private val packetIO: Packet
             Log.info("throughput: $throughput")
             viewModel.throughput = throughput
             packetIO.sendPacket(AckPacket(packet.flags, packet.sequenceNumber))
+            done.countDown()
         }
     }
 }

extras/android/BtBench/app/src/main/java/com/github/google/bumble/btbench/Sender.kt

@@ -16,11 +16,10 @@ package com.github.google.bumble.btbench
 
 import java.util.concurrent.Semaphore
 import java.util.logging.Logger
+import kotlin.time.Duration.Companion.milliseconds
 import kotlin.time.DurationUnit
 import kotlin.time.TimeSource
 
-private const val DEFAULT_STARTUP_DELAY = 3000
-
 private val Log = Logger.getLogger("btbench.sender")
 
 class Sender(private val viewModel: AppViewModel, private val packetIO: PacketIO) : IoClient,
@@ -36,8 +35,8 @@ class Sender(private val viewModel: AppViewModel, private val packetIO: PacketIO
     override fun run() {
         viewModel.clear()
 
-        Log.info("startup delay: $DEFAULT_STARTUP_DELAY")
-        Thread.sleep(DEFAULT_STARTUP_DELAY.toLong());
+        Log.info("startup delay: ${viewModel.startupDelay}")
+        Thread.sleep(viewModel.startupDelay.toLong());
         Log.info("running")
 
         Log.info("sending reset")
@@ -47,20 +46,32 @@ class Sender(private val viewModel: AppViewModel, private val packetIO: PacketIO
 
         val packetCount = viewModel.senderPacketCount
         val packetSize = viewModel.senderPacketSize
-        for (i in 0..<packetCount - 1) {
-            packetIO.sendPacket(SequencePacket(0, i, ByteArray(packetSize - 6)))
+        for (i in 0..<packetCount) {
+            var now = TimeSource.Monotonic.markNow()
+            if (viewModel.senderPacketInterval > 0) {
+                val targetTime = startTime + (i * viewModel.senderPacketInterval).milliseconds
+                val delay = targetTime - now
+                if (delay.isPositive()) {
+                    Log.info("sleeping ${delay.inWholeMilliseconds} ms")
+                    Thread.sleep(delay.inWholeMilliseconds)
+                }
+                now = TimeSource.Monotonic.markNow()
+            }
+            val flags = when (i) {
+                packetCount - 1 -> Packet.LAST_FLAG
+                else -> 0
+            }
+            packetIO.sendPacket(
+                SequencePacket(
+                    flags,
+                    i,
+                    (now - startTime).inWholeMicroseconds.toInt(),
+                    ByteArray(packetSize - 10)
+                )
+            )
             bytesSent += packetSize
             viewModel.packetsSent = i + 1
         }
-        packetIO.sendPacket(
-            SequencePacket(
-                Packet.LAST_FLAG,
-                packetCount - 1,
-                ByteArray(packetSize - 6)
-            )
-        )
-        bytesSent += packetSize
-        viewModel.packetsSent = packetCount
 
         // Wait for the ACK
         Log.info("waiting for ACK")

pyproject.toml

@@ -61,15 +61,17 @@ avatar = [
 ]
 pandora = ["bt-test-interfaces >= 0.0.6"]
 documentation = [
-    "mkdocs >= 1.4.0",
-    "mkdocs-material >= 8.5.6",
-    "mkdocstrings[python] >= 0.19.0",
+    "mkdocs >= 1.6.0",
+    "mkdocs-material >= 9.6",
+    "mkdocstrings[python] >= 0.27.0",
 ]
-lc3 = [
-    "lc3 @ git+https://github.com/google/liblc3.git",
+auracast = [
+    "lc3py ; python_version>='3.10' and platform_system=='Linux' and platform_machine=='x86_64'",
+    "sounddevice >= 0.5.1",
 ]
 
 [project.scripts]
+bumble-auracast = "bumble.apps.auracast:main"
 bumble-ble-rpa-tool = "bumble.apps.ble_rpa_tool:main"
 bumble-console = "bumble.apps.console:main"
 bumble-controller-info = "bumble.apps.controller_info:main"
@@ -153,7 +155,7 @@ disable = [
 ]
 
 [tool.pylint.main]
-ignore = "pandora" # FIXME: pylint does not support stubs yet:
+ignore=["pandora", "mobly"] # FIXME: pylint does not support stubs yet
 
 [tool.pylint.typecheck]
 signature-mutators = "AsyncRunner.run_in_task"
@@ -190,6 +192,10 @@ ignore_missing_imports = true
 module = "serial_asyncio.*"
 ignore_missing_imports = true
 
+[[tool.mypy.overrides]]
+module = "sounddevice.*"
+ignore_missing_imports = true
+
 [[tool.mypy.overrides]]
 module = "usb.*"
 ignore_missing_imports = true

tests/aics_test.py

@@ -33,7 +33,7 @@ from bumble.profiles.aics import (
     AudioInputControlPointOpCode,
     ErrorCode,
 )
-from bumble.profiles.vcp import VolumeControlService, VolumeControlServiceProxy
+from bumble.profiles.vcs import VolumeControlService, VolumeControlServiceProxy
 
 from .test_utils import TwoDevices
 

tests/gatt_service_test.py

@@ -16,6 +16,7 @@
 # Imports
 # -----------------------------------------------------------------------------
 from __future__ import annotations
+import pytest
 
 from . import test_utils
 
@@ -25,6 +26,7 @@ from bumble.profiles import gatt_service
 
 
 # -----------------------------------------------------------------------------
+@pytest.mark.asyncio
 async def test_database_hash():
     devices = await test_utils.TwoDevices.create_with_connection()
     devices[0].gatt_server.services.clear()
@@ -118,6 +120,7 @@ async def test_database_hash():
 
 
 # -----------------------------------------------------------------------------
+@pytest.mark.asyncio
 async def test_service_changed():
     devices = await test_utils.TwoDevices.create_with_connection()
     assert (service := devices[0].gatt_service)

tests/gatt_test.py

@@ -17,32 +17,43 @@
 # -----------------------------------------------------------------------------
 from __future__ import annotations
 import asyncio
+import enum
 import logging
 import os
 import struct
 import pytest
+from typing import Any
 from typing_extensions import Self
 from unittest.mock import AsyncMock, Mock, ANY
 
 from bumble.controller import Controller
-from bumble.gatt_client import CharacteristicProxy
 from bumble.link import LocalLink
 from bumble.device import Device, Peer
 from bumble.host import Host
 from bumble.gatt import (
     GATT_BATTERY_LEVEL_CHARACTERISTIC,
     GATT_CLIENT_CHARACTERISTIC_CONFIGURATION_DESCRIPTOR,
-    CharacteristicAdapter,
-    SerializableCharacteristicAdapter,
-    DelegatedCharacteristicAdapter,
-    PackedCharacteristicAdapter,
-    MappedCharacteristicAdapter,
-    UTF8CharacteristicAdapter,
     Service,
     Characteristic,
     CharacteristicValue,
     Descriptor,
 )
+from bumble.gatt_client import CharacteristicProxy
+from bumble.gatt_adapters import (
+    CharacteristicProxyAdapter,
+    SerializableCharacteristicAdapter,
+    SerializableCharacteristicProxyAdapter,
+    DelegatedCharacteristicAdapter,
+    DelegatedCharacteristicProxyAdapter,
+    PackedCharacteristicAdapter,
+    PackedCharacteristicProxyAdapter,
+    MappedCharacteristicAdapter,
+    MappedCharacteristicProxyAdapter,
+    UTF8CharacteristicAdapter,
+    UTF8CharacteristicProxyAdapter,
+    EnumCharacteristicAdapter,
+    EnumCharacteristicProxyAdapter,
+)
 from bumble.transport import AsyncPipeSink
 from bumble.core import UUID
 from bumble.att import (
@@ -199,7 +210,7 @@ async def test_characteristic_encoding():
     await async_barrier()
     assert characteristic.value == bytes([125])
 
-    cd = DelegatedCharacteristicAdapter(c, encode=lambda x: bytes([x // 2]))
+    cd = DelegatedCharacteristicProxyAdapter(c, encode=lambda x: bytes([x // 2]))
     await cd.write_value(100, with_response=True)
     await async_barrier()
     assert characteristic.value == bytes([50])
@@ -207,7 +218,7 @@ async def test_characteristic_encoding():
     c2 = peer.get_characteristics_by_uuid(async_characteristic.uuid)
     assert len(c2) == 1
     c2 = c2[0]
-    cd2 = PackedCharacteristicAdapter(c2, ">I")
+    cd2 = PackedCharacteristicProxyAdapter(c2, ">I")
     cd2v = await cd2.read_value()
     assert cd2v == 0x05060708
 
@@ -249,7 +260,7 @@ async def test_characteristic_encoding():
     await async_barrier()
     assert last_change is None
 
-    cd = DelegatedCharacteristicAdapter(c, decode=lambda x: x[0])
+    cd = DelegatedCharacteristicProxyAdapter(c, decode=lambda x: x[0])
     await cd.subscribe(on_change)
     await server.notify_subscribers(characteristic)
     await async_barrier()
@@ -314,21 +325,16 @@ async def test_attribute_getters():
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
 async def test_CharacteristicAdapter() -> None:
-    # Check that the CharacteristicAdapter base class is transparent
     v = bytes([1, 2, 3])
-    c = Characteristic(
+    c: Characteristic[Any] = Characteristic(
         GATT_BATTERY_LEVEL_CHARACTERISTIC,
         Characteristic.Properties.READ,
         Characteristic.READABLE,
         v,
     )
-    a = CharacteristicAdapter(c)
-
-    value = await a.read_value(None)
-    assert value == v
 
     v = bytes([3, 4, 5])
-    await a.write_value(None, v)
+    await c.write_value(None, v)
     assert c.value == v
 
     # Simple delegated adapter
@@ -415,11 +421,171 @@ async def test_CharacteristicAdapter() -> None:
 
     class_read_value = await class_c.read_value(None)
     assert class_read_value == class_value_bytes
-    c.value = b''
+    class_c.value = b''
     await class_c.write_value(None, class_value_bytes)
-    assert isinstance(c.value, BlaBla)
-    assert c.value.a == 3
-    assert c.value.b == 4
+    assert isinstance(class_c.value, BlaBla)
+    assert class_c.value.a == class_value.a
+    assert class_c.value.b == class_value.b
+
+    # Enum adapter
+    class MyEnum(enum.IntEnum):
+        ENUM_1 = 1234
+        ENUM_2 = 5678
+
+    enum_value = MyEnum.ENUM_2
+    enum_value_bytes = int(enum_value).to_bytes(3, 'big')
+    c.value = enum_value
+    enum_c = EnumCharacteristicAdapter(c, MyEnum, 3, 'big')
+    enum_read_value = await enum_c.read_value(None)
+    assert enum_read_value == enum_value_bytes
+    enum_c.value = b''
+    await enum_c.write_value(None, enum_value_bytes)
+    assert isinstance(enum_c.value, MyEnum)
+    assert enum_c.value == enum_value
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_CharacteristicProxyAdapter() -> None:
+    class Client:
+        def __init__(self, value):
+            self.value = value
+
+        async def read_value(self, handle, no_long_read=False) -> bytes:
+            return self.value
+
+        async def write_value(self, handle, value, with_response=False):
+            self.value = value
+
+    class TestAttributeProxy(CharacteristicProxy):
+        def __init__(self, value) -> None:
+            super().__init__(Client(value), 0, 0, None, 0)  # type: ignore
+
+        @property
+        def value(self):
+            return self.client.value
+
+        @value.setter
+        def value(self, value):
+            self.client.value = value
+
+    v = bytes([1, 2, 3])
+    c = TestAttributeProxy(v)
+    a: CharacteristicProxyAdapter = CharacteristicProxyAdapter(c)
+
+    value = await a.read_value()
+    assert value == v
+
+    v = bytes([3, 4, 5])
+    await a.write_value(v)
+    assert c.value == v
+
+    # Simple delegated adapter
+    delegated = DelegatedCharacteristicProxyAdapter(
+        c, lambda x: bytes(reversed(x)), lambda x: bytes(reversed(x))
+    )
+
+    delegated_value = await delegated.read_value()
+    assert delegated_value == bytes(reversed(v))
+
+    delegated_value2 = bytes([3, 4, 5])
+    await delegated.write_value(delegated_value2)
+    assert c.value == bytes(reversed(delegated_value2))
+
+    # Packed adapter with single element format
+    packed_value_ref = 1234
+    packed_value_bytes = struct.pack('>H', packed_value_ref)
+    c.value = packed_value_bytes
+    packed = PackedCharacteristicProxyAdapter(c, '>H')
+
+    packed_value_read = await packed.read_value()
+    assert packed_value_read == packed_value_ref
+    c.value = None
+    await packed.write_value(packed_value_ref)
+    assert c.value == packed_value_bytes
+
+    # Packed adapter with multi-element format
+    v1 = 1234
+    v2 = 5678
+    packed_multi_value_bytes = struct.pack('>HH', v1, v2)
+    c.value = packed_multi_value_bytes
+    packed_multi = PackedCharacteristicProxyAdapter(c, '>HH')
+
+    packed_multi_read_value = await packed_multi.read_value()
+    assert packed_multi_read_value == (v1, v2)
+    c.value = b''
+    await packed_multi.write_value((v1, v2))
+    assert c.value == packed_multi_value_bytes
+
+    # Mapped adapter
+    v1 = 1234
+    v2 = 5678
+    packed_mapped_value_bytes = struct.pack('>HH', v1, v2)
+    mapped = {'v1': v1, 'v2': v2}
+    c.value = packed_mapped_value_bytes
+    packed_mapped = MappedCharacteristicProxyAdapter(c, '>HH', ('v1', 'v2'))
+
+    packed_mapped_read_value = await packed_mapped.read_value()
+    assert packed_mapped_read_value == mapped
+    c.value = b''
+    await packed_mapped.write_value(mapped)
+    assert c.value == packed_mapped_value_bytes
+
+    # UTF-8 adapter
+    string_value = 'Hello π'
+    string_value_bytes = string_value.encode('utf-8')
+    c.value = string_value_bytes
+    string_c = UTF8CharacteristicProxyAdapter(c)
+
+    string_read_value = await string_c.read_value()
+    assert string_read_value == string_value
+    c.value = b''
+    await string_c.write_value(string_value)
+    assert c.value == string_value_bytes
+
+    # Class adapter
+    class BlaBla:
+        def __init__(self, a: int, b: int) -> None:
+            self.a = a
+            self.b = b
+
+        @classmethod
+        def from_bytes(cls, data: bytes) -> Self:
+            a, b = struct.unpack(">II", data)
+            return cls(a, b)
+
+        def __bytes__(self) -> bytes:
+            return struct.pack(">II", self.a, self.b)
+
+    class_value = BlaBla(3, 4)
+    class_value_bytes = struct.pack(">II", 3, 4)
+    c.value = class_value_bytes
+    class_c = SerializableCharacteristicProxyAdapter(c, BlaBla)
+
+    class_read_value = await class_c.read_value()
+    assert isinstance(class_read_value, BlaBla)
+    assert class_read_value.a == class_value.a
+    assert class_read_value.b == class_value.b
+    c.value = b''
+    await class_c.write_value(class_value)
+    assert c.value == class_value_bytes
+
+    # Enum adapter
+    class MyEnum(enum.IntEnum):
+        ENUM_1 = 1234
+        ENUM_2 = 5678
+
+    enum_value = MyEnum.ENUM_1
+    enum_value_bytes = int(enum_value).to_bytes(3, 'little')
+    c.value = enum_value_bytes
+    enum_c = EnumCharacteristicProxyAdapter(c, MyEnum, 3)
+
+    enum_read_value = await enum_c.read_value()
+    assert isinstance(enum_read_value, MyEnum)
+    assert enum_read_value == enum_value
+    c.value = b''
+    await enum_c.write_value(enum_value)
+    assert c.value == enum_value_bytes
 
 
 # -----------------------------------------------------------------------------
@@ -601,7 +767,7 @@ async def test_read_write2():
     v1 = await c1.read_value()
     assert v1 == v
 
-    a1 = PackedCharacteristicAdapter(c1, '>I')
+    a1 = PackedCharacteristicProxyAdapter(c1, '>I')
     v1 = await a1.read_value()
     assert v1 == struct.unpack('>I', v)[0]
 
@@ -1114,6 +1280,7 @@ async def async_main():
     await test_CharacteristicValue()
     await test_CharacteristicValue_async()
     await test_CharacteristicAdapter()
+    await test_CharacteristicProxyAdapter()
 
 
 # -----------------------------------------------------------------------------

tests/gmap_test.py

@@ -78,7 +78,11 @@ async def test_init_service(gmap_client: GamingAudioServiceProxy):
         | GmapRole.BROADCAST_GAME_RECEIVER
         | GmapRole.BROADCAST_GAME_SENDER
     )
+    assert gmap_client.ugg_features is not None
     assert await gmap_client.ugg_features.read_value() == UggFeatures.UGG_MULTISINK
+    assert gmap_client.ugt_features is not None
     assert await gmap_client.ugt_features.read_value() == UgtFeatures.UGT_SOURCE
+    assert gmap_client.bgr_features is not None
     assert await gmap_client.bgr_features.read_value() == BgrFeatures.BGR_MULTISINK
+    assert gmap_client.bgs_features is not None
     assert await gmap_client.bgs_features.read_value() == BgsFeatures.BGS_96_KBPS

tests/import_test.py

@@ -53,7 +53,7 @@ def test_import():
         le_audio,
         pacs,
         pbp,
-        vcp,
+        vcs,
     )
 
     assert att
@@ -87,7 +87,7 @@ def test_import():
     assert le_audio
     assert pacs
     assert pbp
-    assert vcp
+    assert vcs
 
 
 # -----------------------------------------------------------------------------

tests/vcp_test.py

@@ -20,7 +20,7 @@ import pytest_asyncio
 import logging
 
 from bumble import device
-from bumble.profiles import vcp
+from bumble.profiles import vcs
 from .test_utils import TwoDevices
 
 # -----------------------------------------------------------------------------
@@ -34,7 +34,7 @@ logger = logging.getLogger(__name__)
 async def vcp_client():
     devices = TwoDevices()
     devices[0].add_service(
-        vcp.VolumeControlService(volume_setting=32, muted=1, volume_flags=1)
+        vcs.VolumeControlService(volume_setting=32, muted=1, volume_flags=1)
     )
 
     await devices.setup_connection()
@@ -48,76 +48,76 @@ async def vcp_client():
 
     peer = device.Peer(devices.connections[1])
     vcp_client = await peer.discover_service_and_create_proxy(
-        vcp.VolumeControlServiceProxy
+        vcs.VolumeControlServiceProxy
     )
     yield vcp_client
 
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_init_service(vcp_client: vcp.VolumeControlServiceProxy):
+async def test_init_service(vcp_client: vcs.VolumeControlServiceProxy):
     assert (await vcp_client.volume_flags.read_value()) == 1
-    assert (await vcp_client.volume_state.read_value()) == (32, 1, 0)
+    assert (await vcp_client.volume_state.read_value()) == vcs.VolumeState(32, 1, 0)
 
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_relative_volume_down(vcp_client: vcp.VolumeControlServiceProxy):
+async def test_relative_volume_down(vcp_client: vcs.VolumeControlServiceProxy):
     await vcp_client.volume_control_point.write_value(
-        bytes([vcp.VolumeControlPointOpcode.RELATIVE_VOLUME_DOWN, 0])
+        bytes([vcs.VolumeControlPointOpcode.RELATIVE_VOLUME_DOWN, 0])
     )
-    assert (await vcp_client.volume_state.read_value()) == (16, 1, 1)
+    assert (await vcp_client.volume_state.read_value()) == vcs.VolumeState(16, 1, 1)
 
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_relative_volume_up(vcp_client: vcp.VolumeControlServiceProxy):
+async def test_relative_volume_up(vcp_client: vcs.VolumeControlServiceProxy):
     await vcp_client.volume_control_point.write_value(
-        bytes([vcp.VolumeControlPointOpcode.RELATIVE_VOLUME_UP, 0])
+        bytes([vcs.VolumeControlPointOpcode.RELATIVE_VOLUME_UP, 0])
     )
-    assert (await vcp_client.volume_state.read_value()) == (48, 1, 1)
+    assert (await vcp_client.volume_state.read_value()) == vcs.VolumeState(48, 1, 1)
 
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_unmute_relative_volume_down(vcp_client: vcp.VolumeControlServiceProxy):
+async def test_unmute_relative_volume_down(vcp_client: vcs.VolumeControlServiceProxy):
     await vcp_client.volume_control_point.write_value(
-        bytes([vcp.VolumeControlPointOpcode.UNMUTE_RELATIVE_VOLUME_DOWN, 0])
+        bytes([vcs.VolumeControlPointOpcode.UNMUTE_RELATIVE_VOLUME_DOWN, 0])
     )
-    assert (await vcp_client.volume_state.read_value()) == (16, 0, 1)
+    assert (await vcp_client.volume_state.read_value()) == vcs.VolumeState(16, 0, 1)
 
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_unmute_relative_volume_up(vcp_client: vcp.VolumeControlServiceProxy):
+async def test_unmute_relative_volume_up(vcp_client: vcs.VolumeControlServiceProxy):
     await vcp_client.volume_control_point.write_value(
-        bytes([vcp.VolumeControlPointOpcode.UNMUTE_RELATIVE_VOLUME_UP, 0])
+        bytes([vcs.VolumeControlPointOpcode.UNMUTE_RELATIVE_VOLUME_UP, 0])
     )
-    assert (await vcp_client.volume_state.read_value()) == (48, 0, 1)
+    assert (await vcp_client.volume_state.read_value()) == vcs.VolumeState(48, 0, 1)
 
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_set_absolute_volume(vcp_client: vcp.VolumeControlServiceProxy):
+async def test_set_absolute_volume(vcp_client: vcs.VolumeControlServiceProxy):
     await vcp_client.volume_control_point.write_value(
-        bytes([vcp.VolumeControlPointOpcode.SET_ABSOLUTE_VOLUME, 0, 255])
+        bytes([vcs.VolumeControlPointOpcode.SET_ABSOLUTE_VOLUME, 0, 255])
     )
-    assert (await vcp_client.volume_state.read_value()) == (255, 1, 1)
+    assert (await vcp_client.volume_state.read_value()) == vcs.VolumeState(255, 1, 1)
 
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_mute(vcp_client: vcp.VolumeControlServiceProxy):
+async def test_mute(vcp_client: vcs.VolumeControlServiceProxy):
     await vcp_client.volume_control_point.write_value(
-        bytes([vcp.VolumeControlPointOpcode.MUTE, 0])
+        bytes([vcs.VolumeControlPointOpcode.MUTE, 0])
     )
-    assert (await vcp_client.volume_state.read_value()) == (32, 1, 0)
+    assert (await vcp_client.volume_state.read_value()) == vcs.VolumeState(32, 1, 0)
 
 
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
-async def test_unmute(vcp_client: vcp.VolumeControlServiceProxy):
+async def test_unmute(vcp_client: vcs.VolumeControlServiceProxy):
     await vcp_client.volume_control_point.write_value(
-        bytes([vcp.VolumeControlPointOpcode.UNMUTE, 0])
+        bytes([vcs.VolumeControlPointOpcode.UNMUTE, 0])
     )
-    assert (await vcp_client.volume_state.read_value()) == (32, 0, 1)
+    assert (await vcp_client.volume_state.read_value()) == vcs.VolumeState(32, 0, 1)

tests/vocs_test.py

@@ -32,9 +32,8 @@ from bumble.profiles.vocs import (
     SetVolumeOffsetOpCode,
     VolumeOffsetControlServiceProxy,
     VolumeOffsetState,
-    VocsAudioLocation,
 )
-from bumble.profiles.vcp import VolumeControlService, VolumeControlServiceProxy
+from bumble.profiles.vcs import VolumeControlService, VolumeControlServiceProxy
 from bumble.profiles.bap import AudioLocation
 
 from .test_utils import TwoDevices
@@ -81,9 +80,7 @@ async def test_init_service(vocs_client: VolumeOffsetControlServiceProxy):
         volume_offset=0,
         change_counter=0,
     )
-    assert await vocs_client.audio_location.read_value() == VocsAudioLocation(
-        audio_location=AudioLocation.NOT_ALLOWED
-    )
+    assert await vocs_client.audio_location.read_value() == AudioLocation.NOT_ALLOWED
     description = await vocs_client.audio_output_description.read_value()
     assert description == ''
 
@@ -162,11 +159,9 @@ async def test_set_volume_offset(vocs_client: VolumeOffsetControlServiceProxy):
 
 @pytest.mark.asyncio
 async def test_set_audio_channel_location(vocs_client: VolumeOffsetControlServiceProxy):
-    new_audio_location = VocsAudioLocation(audio_location=AudioLocation.FRONT_LEFT)
+    new_audio_location = AudioLocation.FRONT_LEFT
 
-    await vocs_client.audio_location.write_value(
-        struct.pack('<I', new_audio_location.audio_location)
-    )
+    await vocs_client.audio_location.write_value(new_audio_location)
 
     location = await vocs_client.audio_location.read_value()
     assert location == new_audio_location