Telethon/telethon/network/mtprotosender.py
2020-12-11 21:43:39 +01:00

805 lines
32 KiB
Python

import asyncio
import collections
import struct
from . import authenticator
from ..extensions.messagepacker import MessagePacker
from .mtprotoplainsender import MTProtoPlainSender
from .requeststate import RequestState
from .mtprotostate import MTProtoState
from ..tl.tlobject import TLRequest
from .. import helpers, utils
from ..errors import (
BadMessageError, InvalidBufferError, SecurityError,
TypeNotFoundError, rpc_message_to_error
)
from ..extensions import BinaryReader
from ..tl.core import RpcResult, MessageContainer, GzipPacked
from ..tl.functions.auth import LogOutRequest
from ..tl.functions import PingRequest
from ..tl.types import (
MsgsAck, Pong, BadServerSalt, BadMsgNotification, FutureSalts,
MsgNewDetailedInfo, NewSessionCreated, MsgDetailedInfo, MsgsStateReq,
MsgsStateInfo, MsgsAllInfo, MsgResendReq, upload
)
from ..crypto import AuthKey
from ..helpers import retry_range
class MTProtoSender:
"""
MTProto Mobile Protocol sender
(https://core.telegram.org/mtproto/description).
This class is responsible for wrapping requests into `TLMessage`'s,
sending them over the network and receiving them in a safe manner.
Automatic reconnection due to temporary network issues is a concern
for this class as well, including retry of messages that could not
be sent successfully.
A new authorization key will be generated on connection if no other
key exists yet.
"""
def __init__(self, auth_key, *, loggers,
retries=5, delay=1, auto_reconnect=True, connect_timeout=None,
auth_key_callback=None,
update_callback=None, auto_reconnect_callback=None):
self._connection = None
self._loggers = loggers
self._log = loggers[__name__]
self._retries = retries
self._delay = delay
self._auto_reconnect = auto_reconnect
self._connect_timeout = connect_timeout
self._auth_key_callback = auth_key_callback
self._update_callback = update_callback
self._auto_reconnect_callback = auto_reconnect_callback
self._connect_lock = asyncio.Lock()
self._ping = None
# Whether the user has explicitly connected or disconnected.
#
# If a disconnection happens for any other reason and it
# was *not* user action then the pending messages won't
# be cleared but on explicit user disconnection all the
# pending futures should be cancelled.
self._user_connected = False
self._reconnecting = False
self._disconnected = asyncio.get_event_loop().create_future()
self._disconnected.set_result(None)
# We need to join the loops upon disconnection
self._send_loop_handle = None
self._recv_loop_handle = None
# Preserving the references of the AuthKey and state is important
self.auth_key = auth_key or AuthKey(None)
self._state = MTProtoState(self.auth_key, loggers=self._loggers)
# Outgoing messages are put in a queue and sent in a batch.
# Note that here we're also storing their ``_RequestState``.
self._send_queue = MessagePacker(self._state, loggers=self._loggers)
# Sent states are remembered until a response is received.
self._pending_state = {}
# Responses must be acknowledged, and we can also batch these.
self._pending_ack = set()
# Similar to pending_messages but only for the last acknowledges.
# These can't go in pending_messages because no acknowledge for them
# is received, but we may still need to resend their state on bad salts.
self._last_acks = collections.deque(maxlen=10)
# Jump table from response ID to method that handles it
self._handlers = {
RpcResult.CONSTRUCTOR_ID: self._handle_rpc_result,
MessageContainer.CONSTRUCTOR_ID: self._handle_container,
GzipPacked.CONSTRUCTOR_ID: self._handle_gzip_packed,
Pong.CONSTRUCTOR_ID: self._handle_pong,
BadServerSalt.CONSTRUCTOR_ID: self._handle_bad_server_salt,
BadMsgNotification.CONSTRUCTOR_ID: self._handle_bad_notification,
MsgDetailedInfo.CONSTRUCTOR_ID: self._handle_detailed_info,
MsgNewDetailedInfo.CONSTRUCTOR_ID: self._handle_new_detailed_info,
NewSessionCreated.CONSTRUCTOR_ID: self._handle_new_session_created,
MsgsAck.CONSTRUCTOR_ID: self._handle_ack,
FutureSalts.CONSTRUCTOR_ID: self._handle_future_salts,
MsgsStateReq.CONSTRUCTOR_ID: self._handle_state_forgotten,
MsgResendReq.CONSTRUCTOR_ID: self._handle_state_forgotten,
MsgsAllInfo.CONSTRUCTOR_ID: self._handle_msg_all,
}
# Public API
async def connect(self, connection):
"""
Connects to the specified given connection using the given auth key.
"""
async with self._connect_lock:
if self._user_connected:
self._log.info('User is already connected!')
return False
self._connection = connection
await self._connect()
self._user_connected = True
return True
def is_connected(self):
return self._user_connected
def _transport_connected(self):
return (
not self._reconnecting
and self._connection is not None
and self._connection._connected
)
async def disconnect(self):
"""
Cleanly disconnects the instance from the network, cancels
all pending requests, and closes the send and receive loops.
"""
await self._disconnect()
def send(self, request, ordered=False):
"""
This method enqueues the given request to be sent. Its send
state will be saved until a response arrives, and a ``Future``
that will be resolved when the response arrives will be returned:
.. code-block:: python
async def method():
# Sending (enqueued for the send loop)
future = sender.send(request)
# Receiving (waits for the receive loop to read the result)
result = await future
Designed like this because Telegram may send the response at
any point, and it can send other items while one waits for it.
Once the response for this future arrives, it is set with the
received result, quite similar to how a ``receive()`` call
would otherwise work.
Since the receiving part is "built in" the future, it's
impossible to await receive a result that was never sent.
"""
if not self._user_connected:
raise ConnectionError('Cannot send requests while disconnected')
if not utils.is_list_like(request):
try:
state = RequestState(request)
except struct.error as e:
# "struct.error: required argument is not an integer" is not
# very helpful; log the request to find out what wasn't int.
self._log.error('Request caused struct.error: %s: %s', e, request)
raise
self._send_queue.append(state)
return state.future
else:
states = []
futures = []
state = None
for req in request:
try:
state = RequestState(req, after=ordered and state)
except struct.error as e:
self._log.error('Request caused struct.error: %s: %s', e, request)
raise
states.append(state)
futures.append(state.future)
self._send_queue.extend(states)
return futures
@property
def disconnected(self):
"""
Future that resolves when the connection to Telegram
ends, either by user action or in the background.
Note that it may resolve in either a ``ConnectionError``
or any other unexpected error that could not be handled.
"""
return asyncio.shield(self._disconnected)
# Private methods
async def _connect(self):
"""
Performs the actual connection, retrying, generating the
authorization key if necessary, and starting the send and
receive loops.
"""
self._log.info('Connecting to %s...', self._connection)
connected = False
for attempt in retry_range(self._retries):
if not connected:
connected = await self._try_connect(attempt)
if not connected:
continue # skip auth key generation until we're connected
if not self.auth_key:
try:
if not await self._try_gen_auth_key(attempt):
continue # keep retrying until we have the auth key
except (IOError, asyncio.TimeoutError) as e:
# Sometimes, specially during user-DC migrations,
# Telegram may close the connection during auth_key
# generation. If that's the case, we will need to
# connect again.
self._log.warning('Connection error %d during auth_key gen: %s: %s',
attempt, type(e).__name__, e)
# Whatever the IOError was, make sure to disconnect so we can
# reconnect cleanly after.
await self._connection.disconnect()
connected = False
await asyncio.sleep(self._delay)
continue # next iteration we will try to reconnect
break # all steps done, break retry loop
else:
if not connected:
raise ConnectionError('Connection to Telegram failed {} time(s)'.format(self._retries))
e = ConnectionError('auth_key generation failed {} time(s)'.format(self._retries))
await self._disconnect(error=e)
raise e
loop = asyncio.get_event_loop()
self._log.debug('Starting send loop')
self._send_loop_handle = loop.create_task(self._send_loop())
self._log.debug('Starting receive loop')
self._recv_loop_handle = loop.create_task(self._recv_loop())
# _disconnected only completes after manual disconnection
# or errors after which the sender cannot continue such
# as failing to reconnect or any unexpected error.
if self._disconnected.done():
self._disconnected = loop.create_future()
self._log.info('Connection to %s complete!', self._connection)
async def _try_connect(self, attempt):
try:
self._log.debug('Connection attempt %d...', attempt)
await self._connection.connect(timeout=self._connect_timeout)
self._log.debug('Connection success!')
return True
except (IOError, asyncio.TimeoutError) as e:
self._log.warning('Attempt %d at connecting failed: %s: %s',
attempt, type(e).__name__, e)
await asyncio.sleep(self._delay)
return False
async def _try_gen_auth_key(self, attempt):
plain = MTProtoPlainSender(self._connection, loggers=self._loggers)
try:
self._log.debug('New auth_key attempt %d...', attempt)
self.auth_key.key, self._state.time_offset = \
await authenticator.do_authentication(plain)
# This is *EXTREMELY* important since we don't control
# external references to the authorization key, we must
# notify whenever we change it. This is crucial when we
# switch to different data centers.
if self._auth_key_callback:
self._auth_key_callback(self.auth_key)
self._log.debug('auth_key generation success!')
return True
except (SecurityError, AssertionError) as e:
self._log.warning('Attempt %d at new auth_key failed: %s', attempt, e)
await asyncio.sleep(self._delay)
return False
async def _disconnect(self, error=None):
if self._connection is None:
self._log.info('Not disconnecting (already have no connection)')
return
self._log.info('Disconnecting from %s...', self._connection)
self._user_connected = False
try:
self._log.debug('Closing current connection...')
await self._connection.disconnect()
finally:
self._log.debug('Cancelling %d pending message(s)...', len(self._pending_state))
for state in self._pending_state.values():
if error and not state.future.done():
state.future.set_exception(error)
else:
state.future.cancel()
self._pending_state.clear()
await helpers._cancel(
self._log,
send_loop_handle=self._send_loop_handle,
recv_loop_handle=self._recv_loop_handle
)
self._log.info('Disconnection from %s complete!', self._connection)
self._connection = None
if self._disconnected and not self._disconnected.done():
if error:
self._disconnected.set_exception(error)
else:
self._disconnected.set_result(None)
async def _reconnect(self, last_error):
"""
Cleanly disconnects and then reconnects.
"""
self._log.info('Closing current connection to begin reconnect...')
await self._connection.disconnect()
await helpers._cancel(
self._log,
send_loop_handle=self._send_loop_handle,
recv_loop_handle=self._recv_loop_handle
)
# TODO See comment in `_start_reconnect`
# Perhaps this should be the last thing to do?
# But _connect() creates tasks which may run and,
# if they see that reconnecting is True, they will end.
# Perhaps that task creation should not belong in connect?
self._reconnecting = False
# Start with a clean state (and thus session ID) to avoid old msgs
self._state.reset()
retries = self._retries if self._auto_reconnect else 0
attempt = 0
ok = True
# We're already "retrying" to connect, so we don't want to force retries
for attempt in retry_range(retries, force_retry=False):
try:
await self._connect()
except (IOError, asyncio.TimeoutError) as e:
last_error = e
self._log.info('Failed reconnection attempt %d with %s',
attempt, e.__class__.__name__)
await asyncio.sleep(self._delay)
except BufferError as e:
# TODO there should probably only be one place to except all these errors
if isinstance(e, InvalidBufferError) and e.code == 404:
self._log.info('Broken authorization key; resetting')
self.auth_key.key = None
if self._auth_key_callback:
self._auth_key_callback(None)
ok = False
break
else:
self._log.warning('Invalid buffer %s', e)
except Exception as e:
last_error = e
self._log.exception('Unexpected exception reconnecting on '
'attempt %d', attempt)
await asyncio.sleep(self._delay)
else:
self._send_queue.extend(self._pending_state.values())
self._pending_state.clear()
if self._auto_reconnect_callback:
asyncio.get_event_loop().create_task(self._auto_reconnect_callback())
break
else:
ok = False
if not ok:
self._log.error('Automatic reconnection failed %d time(s)', attempt)
# There may be no error (e.g. automatic reconnection was turned off).
error = last_error.with_traceback(None) if last_error else None
await self._disconnect(error=error)
def _start_reconnect(self, error):
"""Starts a reconnection in the background."""
if self._user_connected and not self._reconnecting:
# We set reconnecting to True here and not inside the new task
# because it may happen that send/recv loop calls this again
# while the new task hasn't had a chance to run yet. This race
# condition puts `self.connection` in a bad state with two calls
# to its `connect` without disconnecting, so it creates a second
# receive loop. There can't be two tasks receiving data from
# the reader, since that causes an error, and the library just
# gets stuck.
# TODO It still gets stuck? Investigate where and why.
self._reconnecting = True
asyncio.get_event_loop().create_task(self._reconnect(error))
def _keepalive_ping(self, rnd_id):
"""
Send a keep-alive ping. If a pong for the last ping was not received
yet, this means we're probably not connected.
"""
# TODO this is ugly, update loop shouldn't worry about this, sender should
if self._ping is None:
self._ping = rnd_id
self.send(PingRequest(rnd_id))
else:
self._start_reconnect(None)
# Loops
async def _send_loop(self):
"""
This loop is responsible for popping items off the send
queue, encrypting them, and sending them over the network.
Besides `connect`, only this method ever sends data.
"""
while self._user_connected and not self._reconnecting:
if self._pending_ack:
ack = RequestState(MsgsAck(list(self._pending_ack)))
self._send_queue.append(ack)
self._last_acks.append(ack)
self._pending_ack.clear()
self._log.debug('Waiting for messages to send...')
# TODO Wait for the connection send queue to be empty?
# This means that while it's not empty we can wait for
# more messages to be added to the send queue.
batch, data = await self._send_queue.get()
if not data:
continue
self._log.debug('Encrypting %d message(s) in %d bytes for sending',
len(batch), len(data))
data = self._state.encrypt_message_data(data)
# Whether sending succeeds or not, the popped requests are now
# pending because they're removed from the queue. If a reconnect
# occurs, they will be removed from pending state and re-enqueued
# so even if the network fails they won't be lost. If they were
# never re-enqueued, the future waiting for a response "locks".
for state in batch:
if not isinstance(state, list):
if isinstance(state.request, TLRequest):
self._pending_state[state.msg_id] = state
else:
for s in state:
if isinstance(s.request, TLRequest):
self._pending_state[s.msg_id] = s
try:
await self._connection.send(data)
except IOError as e:
self._log.info('Connection closed while sending data')
self._start_reconnect(e)
return
self._log.debug('Encrypted messages put in a queue to be sent')
async def _recv_loop(self):
"""
This loop is responsible for reading all incoming responses
from the network, decrypting and handling or dispatching them.
Besides `connect`, only this method ever receives data.
"""
while self._user_connected and not self._reconnecting:
self._log.debug('Receiving items from the network...')
try:
body = await self._connection.recv()
except IOError as e:
self._log.info('Connection closed while receiving data')
self._start_reconnect(e)
return
try:
message = self._state.decrypt_message_data(body)
except TypeNotFoundError as e:
# Received object which we don't know how to deserialize
self._log.info('Type %08x not found, remaining data %r',
e.invalid_constructor_id, e.remaining)
continue
except SecurityError as e:
# A step while decoding had the incorrect data. This message
# should not be considered safe and it should be ignored.
self._log.warning('Security error while unpacking a '
'received message: %s', e)
continue
except BufferError as e:
if isinstance(e, InvalidBufferError) and e.code == 404:
self._log.info('Broken authorization key; resetting')
self.auth_key.key = None
if self._auth_key_callback:
self._auth_key_callback(None)
await self._disconnect(error=e)
else:
self._log.warning('Invalid buffer %s', e)
self._start_reconnect(e)
return
except Exception as e:
self._log.exception('Unhandled error while receiving data')
self._start_reconnect(e)
return
try:
await self._process_message(message)
except Exception:
self._log.exception('Unhandled error while processing msgs')
# Response Handlers
async def _process_message(self, message):
"""
Adds the given message to the list of messages that must be
acknowledged and dispatches control to different ``_handle_*``
method based on its type.
"""
self._pending_ack.add(message.msg_id)
handler = self._handlers.get(message.obj.CONSTRUCTOR_ID,
self._handle_update)
await handler(message)
def _pop_states(self, msg_id):
"""
Pops the states known to match the given ID from pending messages.
This method should be used when the response isn't specific.
"""
state = self._pending_state.pop(msg_id, None)
if state:
return [state]
to_pop = []
for state in self._pending_state.values():
if state.container_id == msg_id:
to_pop.append(state.msg_id)
if to_pop:
return [self._pending_state.pop(x) for x in to_pop]
for ack in self._last_acks:
if ack.msg_id == msg_id:
return [ack]
return []
async def _handle_rpc_result(self, message):
"""
Handles the result for Remote Procedure Calls:
rpc_result#f35c6d01 req_msg_id:long result:bytes = RpcResult;
This is where the future results for sent requests are set.
"""
rpc_result = message.obj
state = self._pending_state.pop(rpc_result.req_msg_id, None)
self._log.debug('Handling RPC result for message %d',
rpc_result.req_msg_id)
if not state:
# TODO We should not get responses to things we never sent
# However receiving a File() with empty bytes is "common".
# See #658, #759 and #958. They seem to happen in a container
# which contain the real response right after.
try:
with BinaryReader(rpc_result.body) as reader:
if not isinstance(reader.tgread_object(), upload.File):
raise ValueError('Not an upload.File')
except (TypeNotFoundError, ValueError):
self._log.info('Received response without parent request: %s', rpc_result.body)
return
if rpc_result.error:
error = rpc_message_to_error(rpc_result.error, state.request)
self._send_queue.append(
RequestState(MsgsAck([state.msg_id])))
if not state.future.cancelled():
state.future.set_exception(error)
else:
with BinaryReader(rpc_result.body) as reader:
result = state.request.read_result(reader)
if not state.future.cancelled():
state.future.set_result(result)
async def _handle_container(self, message):
"""
Processes the inner messages of a container with many of them:
msg_container#73f1f8dc messages:vector<%Message> = MessageContainer;
"""
self._log.debug('Handling container')
for inner_message in message.obj.messages:
await self._process_message(inner_message)
async def _handle_gzip_packed(self, message):
"""
Unpacks the data from a gzipped object and processes it:
gzip_packed#3072cfa1 packed_data:bytes = Object;
"""
self._log.debug('Handling gzipped data')
with BinaryReader(message.obj.data) as reader:
message.obj = reader.tgread_object()
await self._process_message(message)
async def _handle_update(self, message):
try:
assert message.obj.SUBCLASS_OF_ID == 0x8af52aac # crc32(b'Updates')
except AssertionError:
self._log.warning('Note: %s is not an update, not dispatching it %s', message.obj)
return
self._log.debug('Handling update %s', message.obj.__class__.__name__)
if self._update_callback:
self._update_callback(message.obj)
async def _handle_pong(self, message):
"""
Handles pong results, which don't come inside a ``rpc_result``
but are still sent through a request:
pong#347773c5 msg_id:long ping_id:long = Pong;
"""
pong = message.obj
self._log.debug('Handling pong for message %d', pong.msg_id)
if self._ping == pong.ping_id:
self._ping = None
state = self._pending_state.pop(pong.msg_id, None)
if state:
state.future.set_result(pong)
async def _handle_bad_server_salt(self, message):
"""
Corrects the currently used server salt to use the right value
before enqueuing the rejected message to be re-sent:
bad_server_salt#edab447b bad_msg_id:long bad_msg_seqno:int
error_code:int new_server_salt:long = BadMsgNotification;
"""
bad_salt = message.obj
self._log.debug('Handling bad salt for message %d', bad_salt.bad_msg_id)
self._state.salt = bad_salt.new_server_salt
states = self._pop_states(bad_salt.bad_msg_id)
self._send_queue.extend(states)
self._log.debug('%d message(s) will be resent', len(states))
async def _handle_bad_notification(self, message):
"""
Adjusts the current state to be correct based on the
received bad message notification whenever possible:
bad_msg_notification#a7eff811 bad_msg_id:long bad_msg_seqno:int
error_code:int = BadMsgNotification;
"""
bad_msg = message.obj
states = self._pop_states(bad_msg.bad_msg_id)
self._log.debug('Handling bad msg %s', bad_msg)
if bad_msg.error_code in (16, 17):
# Sent msg_id too low or too high (respectively).
# Use the current msg_id to determine the right time offset.
to = self._state.update_time_offset(
correct_msg_id=message.msg_id)
self._log.info('System clock is wrong, set time offset to %ds', to)
elif bad_msg.error_code == 32:
# msg_seqno too low, so just pump it up by some "large" amount
# TODO A better fix would be to start with a new fresh session ID
self._state._sequence += 64
elif bad_msg.error_code == 33:
# msg_seqno too high never seems to happen but just in case
self._state._sequence -= 16
else:
for state in states:
state.future.set_exception(
BadMessageError(state.request, bad_msg.error_code))
return
# Messages are to be re-sent once we've corrected the issue
self._send_queue.extend(states)
self._log.debug('%d messages will be resent due to bad msg',
len(states))
async def _handle_detailed_info(self, message):
"""
Updates the current status with the received detailed information:
msg_detailed_info#276d3ec6 msg_id:long answer_msg_id:long
bytes:int status:int = MsgDetailedInfo;
"""
# TODO https://goo.gl/VvpCC6
msg_id = message.obj.answer_msg_id
self._log.debug('Handling detailed info for message %d', msg_id)
self._pending_ack.add(msg_id)
async def _handle_new_detailed_info(self, message):
"""
Updates the current status with the received detailed information:
msg_new_detailed_info#809db6df answer_msg_id:long
bytes:int status:int = MsgDetailedInfo;
"""
# TODO https://goo.gl/G7DPsR
msg_id = message.obj.answer_msg_id
self._log.debug('Handling new detailed info for message %d', msg_id)
self._pending_ack.add(msg_id)
async def _handle_new_session_created(self, message):
"""
Updates the current status with the received session information:
new_session_created#9ec20908 first_msg_id:long unique_id:long
server_salt:long = NewSession;
"""
# TODO https://goo.gl/LMyN7A
self._log.debug('Handling new session created')
self._state.salt = message.obj.server_salt
async def _handle_ack(self, message):
"""
Handles a server acknowledge about our messages. Normally
these can be ignored except in the case of ``auth.logOut``:
auth.logOut#5717da40 = Bool;
Telegram doesn't seem to send its result so we need to confirm
it manually. No other request is known to have this behaviour.
Since the ID of sent messages consisting of a container is
never returned (unless on a bad notification), this method
also removes containers messages when any of their inner
messages are acknowledged.
"""
ack = message.obj
self._log.debug('Handling acknowledge for %s', str(ack.msg_ids))
for msg_id in ack.msg_ids:
state = self._pending_state.get(msg_id)
if state and isinstance(state.request, LogOutRequest):
del self._pending_state[msg_id]
state.future.set_result(True)
async def _handle_future_salts(self, message):
"""
Handles future salt results, which don't come inside a
``rpc_result`` but are still sent through a request:
future_salts#ae500895 req_msg_id:long now:int
salts:vector<future_salt> = FutureSalts;
"""
# TODO save these salts and automatically adjust to the
# correct one whenever the salt in use expires.
self._log.debug('Handling future salts for message %d', message.msg_id)
state = self._pending_state.pop(message.msg_id, None)
if state:
state.future.set_result(message.obj)
async def _handle_state_forgotten(self, message):
"""
Handles both :tl:`MsgsStateReq` and :tl:`MsgResendReq` by
enqueuing a :tl:`MsgsStateInfo` to be sent at a later point.
"""
self._send_queue.append(RequestState(MsgsStateInfo(
req_msg_id=message.msg_id, info=chr(1) * len(message.obj.msg_ids)
)))
async def _handle_msg_all(self, message):
"""
Handles :tl:`MsgsAllInfo` by doing nothing (yet).
"""