| # Copyright 2021-2022 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 - Generic Attribute Profile |
| # Client |
| # |
| # See Bluetooth spec @ Vol 3, Part G |
| # |
| # ----------------------------------------------------------------------------- |
| |
| # ----------------------------------------------------------------------------- |
| # Imports |
| # ----------------------------------------------------------------------------- |
| import asyncio |
| import logging |
| import struct |
| |
| from colors import color |
| from pyee import EventEmitter |
| |
| from .hci import HCI_Constant |
| from .att import ( |
| ATT_ATTRIBUTE_NOT_FOUND_ERROR, |
| ATT_ATTRIBUTE_NOT_LONG_ERROR, |
| ATT_CID, |
| ATT_DEFAULT_MTU, |
| ATT_ERROR_RESPONSE, |
| ATT_INVALID_OFFSET_ERROR, |
| ATT_PDU, |
| ATT_RESPONSES, |
| ATT_Exchange_MTU_Request, |
| ATT_Find_By_Type_Value_Request, |
| ATT_Find_Information_Request, |
| ATT_Handle_Value_Confirmation, |
| ATT_Read_Blob_Request, |
| ATT_Read_By_Group_Type_Request, |
| ATT_Read_By_Type_Request, |
| ATT_Read_Request, |
| ATT_Write_Command, |
| ATT_Write_Request, |
| ) |
| from . import core |
| from .core import UUID, InvalidStateError, ProtocolError |
| from .gatt import ( |
| GATT_CHARACTERISTIC_ATTRIBUTE_TYPE, |
| GATT_CLIENT_CHARACTERISTIC_CONFIGURATION_DESCRIPTOR, |
| GATT_PRIMARY_SERVICE_ATTRIBUTE_TYPE, |
| GATT_REQUEST_TIMEOUT, |
| GATT_SECONDARY_SERVICE_ATTRIBUTE_TYPE, |
| Characteristic, |
| ClientCharacteristicConfigurationBits, |
| ) |
| |
| # ----------------------------------------------------------------------------- |
| # Logging |
| # ----------------------------------------------------------------------------- |
| logger = logging.getLogger(__name__) |
| |
| |
| # ----------------------------------------------------------------------------- |
| # Proxies |
| # ----------------------------------------------------------------------------- |
| class AttributeProxy(EventEmitter): |
| def __init__(self, client, handle, end_group_handle, attribute_type): |
| EventEmitter.__init__(self) |
| self.client = client |
| self.handle = handle |
| self.end_group_handle = end_group_handle |
| self.type = attribute_type |
| |
| async def read_value(self, no_long_read=False): |
| return self.decode_value( |
| await self.client.read_value(self.handle, no_long_read) |
| ) |
| |
| async def write_value(self, value, with_response=False): |
| return await self.client.write_value( |
| self.handle, self.encode_value(value), with_response |
| ) |
| |
| def encode_value(self, value): |
| return value |
| |
| def decode_value(self, value_bytes): |
| return value_bytes |
| |
| def __str__(self): |
| return f'Attribute(handle=0x{self.handle:04X}, type={self.type})' |
| |
| |
| class ServiceProxy(AttributeProxy): |
| @staticmethod |
| def from_client(service_class, client, service_uuid): |
| # The service and its characteristics are considered to have already been |
| # discovered |
| services = client.get_services_by_uuid(service_uuid) |
| service = services[0] if services else None |
| return service_class(service) if service else None |
| |
| def __init__(self, client, handle, end_group_handle, uuid, primary=True): |
| attribute_type = ( |
| GATT_PRIMARY_SERVICE_ATTRIBUTE_TYPE |
| if primary |
| else GATT_SECONDARY_SERVICE_ATTRIBUTE_TYPE |
| ) |
| super().__init__(client, handle, end_group_handle, attribute_type) |
| self.uuid = uuid |
| self.characteristics = [] |
| |
| async def discover_characteristics(self, uuids=()): |
| return await self.client.discover_characteristics(uuids, self) |
| |
| def get_characteristics_by_uuid(self, uuid): |
| return self.client.get_characteristics_by_uuid(uuid, self) |
| |
| def __str__(self): |
| return f'Service(handle=0x{self.handle:04X}, uuid={self.uuid})' |
| |
| |
| class CharacteristicProxy(AttributeProxy): |
| def __init__(self, client, handle, end_group_handle, uuid, properties): |
| super().__init__(client, handle, end_group_handle, uuid) |
| self.uuid = uuid |
| self.properties = properties |
| self.descriptors = [] |
| self.descriptors_discovered = False |
| self.subscribers = {} # Map from subscriber to proxy subscriber |
| |
| def get_descriptor(self, descriptor_type): |
| for descriptor in self.descriptors: |
| if descriptor.type == descriptor_type: |
| return descriptor |
| |
| return None |
| |
| async def discover_descriptors(self): |
| return await self.client.discover_descriptors(self) |
| |
| async def subscribe(self, subscriber=None, prefer_notify=True): |
| 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 await self.client.subscribe(self, subscriber, prefer_notify) |
| |
| async def unsubscribe(self, subscriber=None): |
| if subscriber in self.subscribers: |
| subscriber = self.subscribers.pop(subscriber) |
| |
| return await self.client.unsubscribe(self, subscriber) |
| |
| def __str__(self): |
| return ( |
| f'Characteristic(handle=0x{self.handle:04X}, ' |
| f'uuid={self.uuid}, ' |
| f'properties={Characteristic.properties_as_string(self.properties)})' |
| ) |
| |
| |
| class DescriptorProxy(AttributeProxy): |
| def __init__(self, client, handle, descriptor_type): |
| super().__init__(client, handle, 0, descriptor_type) |
| |
| def __str__(self): |
| return f'Descriptor(handle=0x{self.handle:04X}, type={self.type})' |
| |
| |
| class ProfileServiceProxy: |
| ''' |
| Base class for profile-specific service proxies |
| ''' |
| |
| @classmethod |
| def from_client(cls, client): |
| return ServiceProxy.from_client(cls, client, cls.SERVICE_CLASS.UUID) |
| |
| |
| # ----------------------------------------------------------------------------- |
| # GATT Client |
| # ----------------------------------------------------------------------------- |
| class Client: |
| def __init__(self, connection): |
| self.connection = connection |
| self.mtu_exchange_done = False |
| self.request_semaphore = asyncio.Semaphore(1) |
| self.pending_request = None |
| self.pending_response = None |
| self.notification_subscribers = ( |
| {} |
| ) # Notification subscribers, by attribute handle |
| self.indication_subscribers = {} # Indication subscribers, by attribute handle |
| self.services = [] |
| |
| def send_gatt_pdu(self, pdu): |
| self.connection.send_l2cap_pdu(ATT_CID, pdu) |
| |
| async def send_command(self, command): |
| logger.debug( |
| f'GATT Command from client: [0x{self.connection.handle:04X}] {command}' |
| ) |
| self.send_gatt_pdu(command.to_bytes()) |
| |
| async def send_request(self, request): |
| logger.debug( |
| f'GATT Request from client: [0x{self.connection.handle:04X}] {request}' |
| ) |
| |
| # Wait until we can send (only one pending command at a time for the connection) |
| response = None |
| async with self.request_semaphore: |
| assert self.pending_request is None |
| assert self.pending_response is None |
| |
| # Create a future value to hold the eventual response |
| self.pending_response = asyncio.get_running_loop().create_future() |
| self.pending_request = request |
| |
| try: |
| self.send_gatt_pdu(request.to_bytes()) |
| response = await asyncio.wait_for( |
| self.pending_response, GATT_REQUEST_TIMEOUT |
| ) |
| except asyncio.TimeoutError as error: |
| logger.warning(color('!!! GATT Request timeout', 'red')) |
| raise core.TimeoutError(f'GATT timeout for {request.name}') from error |
| finally: |
| self.pending_request = None |
| self.pending_response = None |
| |
| return response |
| |
| def send_confirmation(self, confirmation): |
| logger.debug( |
| f'GATT Confirmation from client: [0x{self.connection.handle:04X}] ' |
| f'{confirmation}' |
| ) |
| self.send_gatt_pdu(confirmation.to_bytes()) |
| |
| async def request_mtu(self, mtu): |
| # Check the range |
| if mtu < ATT_DEFAULT_MTU: |
| raise ValueError(f'MTU must be >= {ATT_DEFAULT_MTU}') |
| if mtu > 0xFFFF: |
| raise ValueError('MTU must be <= 0xFFFF') |
| |
| # We can only send one request per connection |
| if self.mtu_exchange_done: |
| return self.connection.att_mtu |
| |
| # Send the request |
| self.mtu_exchange_done = True |
| response = await self.send_request(ATT_Exchange_MTU_Request(client_rx_mtu=mtu)) |
| if response.op_code == ATT_ERROR_RESPONSE: |
| raise ProtocolError( |
| response.error_code, |
| 'att', |
| ATT_PDU.error_name(response.error_code), |
| response, |
| ) |
| |
| # Compute the final MTU |
| self.connection.att_mtu = min(mtu, response.server_rx_mtu) |
| |
| return self.connection.att_mtu |
| |
| def get_services_by_uuid(self, uuid): |
| return [service for service in self.services if service.uuid == uuid] |
| |
| def get_characteristics_by_uuid(self, uuid, service=None): |
| services = [service] if service else self.services |
| return [ |
| c |
| for c in [c for s in services for c in s.characteristics] |
| if c.uuid == uuid |
| ] |
| |
| def on_service_discovered(self, service): |
| '''Add a service to the service list if it wasn't already there''' |
| already_known = False |
| for existing_service in self.services: |
| if existing_service.handle == service.handle: |
| already_known = True |
| break |
| if not already_known: |
| self.services.append(service) |
| |
| async def discover_services(self, uuids=None): |
| ''' |
| See Vol 3, Part G - 4.4.1 Discover All Primary Services |
| ''' |
| starting_handle = 0x0001 |
| services = [] |
| while starting_handle < 0xFFFF: |
| response = await self.send_request( |
| ATT_Read_By_Group_Type_Request( |
| starting_handle=starting_handle, |
| ending_handle=0xFFFF, |
| attribute_group_type=GATT_PRIMARY_SERVICE_ATTRIBUTE_TYPE, |
| ) |
| ) |
| if response is None: |
| # TODO raise appropriate exception |
| return [] |
| |
| # Check if we reached the end of the iteration |
| if response.op_code == ATT_ERROR_RESPONSE: |
| if response.error_code != ATT_ATTRIBUTE_NOT_FOUND_ERROR: |
| # Unexpected end |
| logger.warning( |
| '!!! unexpected error while discovering services: ' |
| f'{HCI_Constant.error_name(response.error_code)}' |
| ) |
| # TODO raise appropriate exception |
| return |
| break |
| |
| for ( |
| attribute_handle, |
| end_group_handle, |
| attribute_value, |
| ) in response.attributes: |
| if ( |
| attribute_handle < starting_handle |
| or end_group_handle < attribute_handle |
| ): |
| # Something's not right |
| logger.warning( |
| f'bogus handle values: {attribute_handle} {end_group_handle}' |
| ) |
| return |
| |
| # Create a service proxy for this service |
| service = ServiceProxy( |
| self, |
| attribute_handle, |
| end_group_handle, |
| UUID.from_bytes(attribute_value), |
| True, |
| ) |
| |
| # Filter out returned services based on the given uuids list |
| if (not uuids) or (service.uuid in uuids): |
| services.append(service) |
| |
| # Add the service to the peer's service list |
| self.on_service_discovered(service) |
| |
| # Stop if for some reason the list was empty |
| if not response.attributes: |
| break |
| |
| # Move on to the next chunk |
| starting_handle = response.attributes[-1][1] + 1 |
| |
| return services |
| |
| async def discover_service(self, uuid): |
| ''' |
| See Vol 3, Part G - 4.4.2 Discover Primary Service by Service UUID |
| ''' |
| |
| # Force uuid to be a UUID object |
| if isinstance(uuid, str): |
| uuid = UUID(uuid) |
| |
| starting_handle = 0x0001 |
| services = [] |
| while starting_handle < 0xFFFF: |
| response = await self.send_request( |
| ATT_Find_By_Type_Value_Request( |
| starting_handle=starting_handle, |
| ending_handle=0xFFFF, |
| attribute_type=GATT_PRIMARY_SERVICE_ATTRIBUTE_TYPE, |
| attribute_value=uuid.to_pdu_bytes(), |
| ) |
| ) |
| if response is None: |
| # TODO raise appropriate exception |
| return [] |
| |
| # Check if we reached the end of the iteration |
| if response.op_code == ATT_ERROR_RESPONSE: |
| if response.error_code != ATT_ATTRIBUTE_NOT_FOUND_ERROR: |
| # Unexpected end |
| logger.warning( |
| '!!! unexpected error while discovering services: ' |
| f'{HCI_Constant.error_name(response.error_code)}' |
| ) |
| # TODO raise appropriate exception |
| return |
| break |
| |
| for attribute_handle, end_group_handle in response.handles_information: |
| if ( |
| attribute_handle < starting_handle |
| or end_group_handle < attribute_handle |
| ): |
| # Something's not right |
| logger.warning( |
| f'bogus handle values: {attribute_handle} {end_group_handle}' |
| ) |
| return |
| |
| # Create a service proxy for this service |
| service = ServiceProxy( |
| self, attribute_handle, end_group_handle, uuid, True |
| ) |
| |
| # Add the service to the peer's service list |
| services.append(service) |
| self.on_service_discovered(service) |
| |
| # Check if we've reached the end already |
| if end_group_handle == 0xFFFF: |
| break |
| |
| # Stop if for some reason the list was empty |
| if not response.handles_information: |
| break |
| |
| # Move on to the next chunk |
| starting_handle = response.handles_information[-1][1] + 1 |
| |
| return services |
| |
| async def discover_included_services(self, _service): |
| ''' |
| See Vol 3, Part G - 4.5.1 Find Included Services |
| ''' |
| # TODO |
| return [] |
| |
| async def discover_characteristics(self, uuids, service): |
| ''' |
| See Vol 3, Part G - 4.6.1 Discover All Characteristics of a Service and 4.6.2 |
| Discover Characteristics by UUID |
| ''' |
| |
| # Cast the UUIDs type from string to object if needed |
| uuids = [UUID(uuid) if isinstance(uuid, str) else uuid for uuid in uuids] |
| |
| # Decide which services to discover for |
| services = [service] if service else self.services |
| |
| # Perform characteristic discovery for each service |
| discovered_characteristics = [] |
| for service in services: |
| starting_handle = service.handle |
| ending_handle = service.end_group_handle |
| |
| characteristics = [] |
| while starting_handle <= ending_handle: |
| response = await self.send_request( |
| ATT_Read_By_Type_Request( |
| starting_handle=starting_handle, |
| ending_handle=ending_handle, |
| attribute_type=GATT_CHARACTERISTIC_ATTRIBUTE_TYPE, |
| ) |
| ) |
| if response is None: |
| # TODO raise appropriate exception |
| return [] |
| |
| # Check if we reached the end of the iteration |
| if response.op_code == ATT_ERROR_RESPONSE: |
| if response.error_code != ATT_ATTRIBUTE_NOT_FOUND_ERROR: |
| # Unexpected end |
| logger.warning( |
| '!!! unexpected error while discovering characteristics: ' |
| f'{HCI_Constant.error_name(response.error_code)}' |
| ) |
| # TODO raise appropriate exception |
| return |
| break |
| |
| # Stop if for some reason the list was empty |
| if not response.attributes: |
| break |
| |
| # Process all characteristics returned in this iteration |
| for attribute_handle, attribute_value in response.attributes: |
| if attribute_handle < starting_handle: |
| # Something's not right |
| logger.warning(f'bogus handle value: {attribute_handle}') |
| return [] |
| |
| properties, handle = struct.unpack_from('<BH', attribute_value) |
| characteristic_uuid = UUID.from_bytes(attribute_value[3:]) |
| characteristic = CharacteristicProxy( |
| self, handle, 0, characteristic_uuid, properties |
| ) |
| |
| # Set the previous characteristic's end handle |
| if characteristics: |
| characteristics[-1].end_group_handle = attribute_handle - 1 |
| |
| characteristics.append(characteristic) |
| |
| # Move on to the next characteristics |
| starting_handle = response.attributes[-1][0] + 1 |
| |
| # Set the end handle for the last characteristic |
| if characteristics: |
| characteristics[-1].end_group_handle = service.end_group_handle |
| |
| # Set the service's characteristics |
| characteristics = [ |
| c for c in characteristics if not uuids or c.uuid in uuids |
| ] |
| service.characteristics = characteristics |
| discovered_characteristics.extend(characteristics) |
| |
| return discovered_characteristics |
| |
| async def discover_descriptors( |
| self, characteristic=None, start_handle=None, end_handle=None |
| ): |
| ''' |
| See Vol 3, Part G - 4.7.1 Discover All Characteristic Descriptors |
| ''' |
| if characteristic: |
| starting_handle = characteristic.handle + 1 |
| ending_handle = characteristic.end_group_handle |
| elif start_handle and end_handle: |
| starting_handle = start_handle |
| ending_handle = end_handle |
| else: |
| return [] |
| |
| descriptors = [] |
| while starting_handle <= ending_handle: |
| response = await self.send_request( |
| ATT_Find_Information_Request( |
| starting_handle=starting_handle, ending_handle=ending_handle |
| ) |
| ) |
| if response is None: |
| # TODO raise appropriate exception |
| return [] |
| |
| # Check if we reached the end of the iteration |
| if response.op_code == ATT_ERROR_RESPONSE: |
| if response.error_code != ATT_ATTRIBUTE_NOT_FOUND_ERROR: |
| # Unexpected end |
| logger.warning( |
| '!!! unexpected error while discovering descriptors: ' |
| f'{HCI_Constant.error_name(response.error_code)}' |
| ) |
| # TODO raise appropriate exception |
| return [] |
| break |
| |
| # Stop if for some reason the list was empty |
| if not response.information: |
| break |
| |
| # Process all descriptors returned in this iteration |
| for attribute_handle, attribute_uuid in response.information: |
| if attribute_handle < starting_handle: |
| # Something's not right |
| logger.warning(f'bogus handle value: {attribute_handle}') |
| return [] |
| |
| descriptor = DescriptorProxy( |
| self, attribute_handle, UUID.from_bytes(attribute_uuid) |
| ) |
| descriptors.append(descriptor) |
| # TODO: read descriptor value |
| |
| # Move on to the next descriptor |
| starting_handle = response.information[-1][0] + 1 |
| |
| # Set the characteristic's descriptors |
| if characteristic: |
| characteristic.descriptors = descriptors |
| |
| return descriptors |
| |
| async def discover_attributes(self): |
| ''' |
| Discover all attributes, regardless of type |
| ''' |
| starting_handle = 0x0001 |
| ending_handle = 0xFFFF |
| attributes = [] |
| while True: |
| response = await self.send_request( |
| ATT_Find_Information_Request( |
| starting_handle=starting_handle, ending_handle=ending_handle |
| ) |
| ) |
| if response is None: |
| return [] |
| |
| # Check if we reached the end of the iteration |
| if response.op_code == ATT_ERROR_RESPONSE: |
| if response.error_code != ATT_ATTRIBUTE_NOT_FOUND_ERROR: |
| # Unexpected end |
| logger.warning( |
| '!!! unexpected error while discovering attributes: ' |
| f'{HCI_Constant.error_name(response.error_code)}' |
| ) |
| return [] |
| break |
| |
| for attribute_handle, attribute_uuid in response.information: |
| if attribute_handle < starting_handle: |
| # Something's not right |
| logger.warning(f'bogus handle value: {attribute_handle}') |
| return [] |
| |
| attribute = AttributeProxy( |
| self, attribute_handle, 0, UUID.from_bytes(attribute_uuid) |
| ) |
| attributes.append(attribute) |
| |
| # Move on to the next attributes |
| starting_handle = attributes[-1].handle + 1 |
| |
| return attributes |
| |
| async def subscribe(self, characteristic, subscriber=None, prefer_notify=True): |
| # If we haven't already discovered the descriptors for this characteristic, |
| # do it now |
| if not characteristic.descriptors_discovered: |
| await self.discover_descriptors(characteristic) |
| |
| # Look for the CCCD descriptor |
| cccd = characteristic.get_descriptor( |
| GATT_CLIENT_CHARACTERISTIC_CONFIGURATION_DESCRIPTOR |
| ) |
| if not cccd: |
| logger.warning('subscribing to characteristic with no CCCD descriptor') |
| return |
| |
| if ( |
| characteristic.properties & Characteristic.NOTIFY |
| and characteristic.properties & Characteristic.INDICATE |
| ): |
| if prefer_notify: |
| bits = ClientCharacteristicConfigurationBits.NOTIFICATION |
| subscribers = self.notification_subscribers |
| else: |
| bits = ClientCharacteristicConfigurationBits.INDICATION |
| subscribers = self.indication_subscribers |
| elif characteristic.properties & Characteristic.NOTIFY: |
| bits = ClientCharacteristicConfigurationBits.NOTIFICATION |
| subscribers = self.notification_subscribers |
| elif characteristic.properties & Characteristic.INDICATE: |
| bits = ClientCharacteristicConfigurationBits.INDICATION |
| subscribers = self.indication_subscribers |
| else: |
| raise InvalidStateError("characteristic is not notify or indicate") |
| |
| # Add subscribers to the sets |
| subscriber_set = subscribers.setdefault(characteristic.handle, set()) |
| if subscriber is not None: |
| subscriber_set.add(subscriber) |
| # Add the characteristic as a subscriber, which will result in the |
| # characteristic emitting an 'update' event when a notification or indication |
| # is received |
| subscriber_set.add(characteristic) |
| |
| await self.write_value(cccd, struct.pack('<H', bits), with_response=True) |
| |
| async def unsubscribe(self, characteristic, subscriber=None): |
| # If we haven't already discovered the descriptors for this characteristic, |
| # do it now |
| if not characteristic.descriptors_discovered: |
| await self.discover_descriptors(characteristic) |
| |
| # Look for the CCCD descriptor |
| cccd = characteristic.get_descriptor( |
| GATT_CLIENT_CHARACTERISTIC_CONFIGURATION_DESCRIPTOR |
| ) |
| if not cccd: |
| logger.warning('unsubscribing from characteristic with no CCCD descriptor') |
| return |
| |
| if subscriber is not None: |
| # Remove matching subscriber from subscriber sets |
| for subscriber_set in ( |
| self.notification_subscribers, |
| self.indication_subscribers, |
| ): |
| subscribers = subscriber_set.get(characteristic.handle, []) |
| if subscriber in subscribers: |
| subscribers.remove(subscriber) |
| |
| # Cleanup if we removed the last one |
| if not subscribers: |
| del subscriber_set[characteristic.handle] |
| else: |
| # Remove all subscribers for this attribute from the sets! |
| self.notification_subscribers.pop(characteristic.handle, None) |
| self.indication_subscribers.pop(characteristic.handle, None) |
| |
| if not self.notification_subscribers and not self.indication_subscribers: |
| # No more subscribers left |
| await self.write_value(cccd, b'\x00\x00', with_response=True) |
| |
| async def read_value(self, attribute, no_long_read=False): |
| ''' |
| See Vol 3, Part G - 4.8.1 Read Characteristic Value |
| |
| `attribute` can be an Attribute object, or a handle value |
| ''' |
| |
| # Send a request to read |
| attribute_handle = attribute if isinstance(attribute, int) else attribute.handle |
| response = await self.send_request( |
| ATT_Read_Request(attribute_handle=attribute_handle) |
| ) |
| if response is None: |
| raise TimeoutError('read timeout') |
| if response.op_code == ATT_ERROR_RESPONSE: |
| raise ProtocolError( |
| response.error_code, |
| 'att', |
| ATT_PDU.error_name(response.error_code), |
| response, |
| ) |
| |
| # If the value is the max size for the MTU, try to read more unless the caller |
| # specifically asked not to do that |
| attribute_value = response.attribute_value |
| if not no_long_read and len(attribute_value) == self.connection.att_mtu - 1: |
| logger.debug('using READ BLOB to get the rest of the value') |
| offset = len(attribute_value) |
| while True: |
| response = await self.send_request( |
| ATT_Read_Blob_Request( |
| attribute_handle=attribute_handle, value_offset=offset |
| ) |
| ) |
| if response is None: |
| raise TimeoutError('read timeout') |
| if response.op_code == ATT_ERROR_RESPONSE: |
| if response.error_code in ( |
| ATT_ATTRIBUTE_NOT_LONG_ERROR, |
| ATT_INVALID_OFFSET_ERROR, |
| ): |
| break |
| raise ProtocolError( |
| response.error_code, |
| 'att', |
| ATT_PDU.error_name(response.error_code), |
| response, |
| ) |
| |
| part = response.part_attribute_value |
| attribute_value += part |
| |
| if len(part) < self.connection.att_mtu - 1: |
| break |
| |
| offset += len(part) |
| |
| # Return the value as bytes |
| return attribute_value |
| |
| async def read_characteristics_by_uuid(self, uuid, service): |
| ''' |
| See Vol 3, Part G - 4.8.2 Read Using Characteristic UUID |
| ''' |
| |
| if service is None: |
| starting_handle = 0x0001 |
| ending_handle = 0xFFFF |
| else: |
| starting_handle = service.handle |
| ending_handle = service.end_group_handle |
| |
| characteristics_values = [] |
| while starting_handle <= ending_handle: |
| response = await self.send_request( |
| ATT_Read_By_Type_Request( |
| starting_handle=starting_handle, |
| ending_handle=ending_handle, |
| attribute_type=uuid, |
| ) |
| ) |
| if response is None: |
| # TODO raise appropriate exception |
| return [] |
| |
| # Check if we reached the end of the iteration |
| if response.op_code == ATT_ERROR_RESPONSE: |
| if response.error_code != ATT_ATTRIBUTE_NOT_FOUND_ERROR: |
| # Unexpected end |
| logger.warning( |
| '!!! unexpected error while reading characteristics: ' |
| f'{HCI_Constant.error_name(response.error_code)}' |
| ) |
| # TODO raise appropriate exception |
| return [] |
| break |
| |
| # Stop if for some reason the list was empty |
| if not response.attributes: |
| break |
| |
| # Process all characteristics returned in this iteration |
| for attribute_handle, attribute_value in response.attributes: |
| if attribute_handle < starting_handle: |
| # Something's not right |
| logger.warning(f'bogus handle value: {attribute_handle}') |
| return [] |
| |
| characteristics_values.append(attribute_value) |
| |
| # Move on to the next characteristics |
| starting_handle = response.attributes[-1][0] + 1 |
| |
| return characteristics_values |
| |
| async def write_value(self, attribute, value, with_response=False): |
| ''' |
| See Vol 3, Part G - 4.9.1 Write Without Response & 4.9.3 Write Characteristic |
| Value |
| |
| `attribute` can be an Attribute object, or a handle value |
| ''' |
| |
| # Send a request or command to write |
| attribute_handle = attribute if isinstance(attribute, int) else attribute.handle |
| if with_response: |
| response = await self.send_request( |
| ATT_Write_Request( |
| attribute_handle=attribute_handle, attribute_value=value |
| ) |
| ) |
| if response.op_code == ATT_ERROR_RESPONSE: |
| raise ProtocolError( |
| response.error_code, |
| 'att', |
| ATT_PDU.error_name(response.error_code), |
| response, |
| ) |
| else: |
| await self.send_command( |
| ATT_Write_Command( |
| attribute_handle=attribute_handle, attribute_value=value |
| ) |
| ) |
| |
| def on_gatt_pdu(self, att_pdu): |
| logger.debug( |
| f'GATT Response to client: [0x{self.connection.handle:04X}] {att_pdu}' |
| ) |
| if att_pdu.op_code in ATT_RESPONSES: |
| if self.pending_request is None: |
| # Not expected! |
| logger.warning('!!! unexpected response, there is no pending request') |
| return |
| |
| # Sanity check: the response should match the pending request unless it is |
| # an error response |
| if att_pdu.op_code != ATT_ERROR_RESPONSE: |
| expected_response_name = self.pending_request.name.replace( |
| '_REQUEST', '_RESPONSE' |
| ) |
| if att_pdu.name != expected_response_name: |
| logger.warning( |
| f'!!! mismatched response: expected {expected_response_name}' |
| ) |
| return |
| |
| # Return the response to the coroutine that is waiting for it |
| self.pending_response.set_result(att_pdu) |
| else: |
| handler_name = f'on_{att_pdu.name.lower()}' |
| handler = getattr(self, handler_name, None) |
| if handler is not None: |
| handler(att_pdu) |
| else: |
| logger.warning( |
| color( |
| '--- Ignoring GATT Response from ' |
| f'[0x{self.connection.handle:04X}]: ', |
| 'red', |
| ) |
| + str(att_pdu) |
| ) |
| |
| def on_att_handle_value_notification(self, notification): |
| # Call all subscribers |
| subscribers = self.notification_subscribers.get( |
| notification.attribute_handle, [] |
| ) |
| if not subscribers: |
| logger.warning('!!! received notification with no subscriber') |
| for subscriber in subscribers: |
| if callable(subscriber): |
| subscriber(notification.attribute_value) |
| else: |
| subscriber.emit('update', notification.attribute_value) |
| |
| def on_att_handle_value_indication(self, indication): |
| # Call all subscribers |
| subscribers = self.indication_subscribers.get(indication.attribute_handle, []) |
| if not subscribers: |
| logger.warning('!!! received indication with no subscriber') |
| for subscriber in subscribers: |
| if callable(subscriber): |
| subscriber(indication.attribute_value) |
| else: |
| subscriber.emit('update', indication.attribute_value) |
| |
| # Confirm that we received the indication |
| self.send_confirmation(ATT_Handle_Value_Confirmation()) |
