Telethon/telethon/network/mtprotoplainsender.py

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"""
This module contains the class used to communicate with Telegram's servers
in plain text, when no authorization key has been created yet.
"""
import struct
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from .mtprotostate import MTProtoState
from ..errors import BrokenAuthKeyError
from ..extensions import BinaryReader
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class MTProtoPlainSender:
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"""
MTProto Mobile Protocol plain sender
(https://core.telegram.org/mtproto/description#unencrypted-messages)
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"""
def __init__(self, connection):
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"""
Initializes the MTProto plain sender.
:param connection: the Connection to be used.
"""
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self._state = MTProtoState(auth_key=None)
self._connection = connection
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async def send(self, request):
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"""
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Sends and receives the result for the given request.
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"""
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body = bytes(request)
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msg_id = self._state._get_new_msg_id()
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await self._connection.send(
struct.pack('<QQi', 0, msg_id, len(body)) + body
)
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body = await self._connection.recv()
if body == b'l\xfe\xff\xff': # -404 little endian signed
# Broken authorization, must reset the auth key
raise BrokenAuthKeyError()
with BinaryReader(body) as reader:
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assert reader.read_long() == 0, 'Bad auth_key_id' # auth_key_id
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assert reader.read_long() != 0, 'Bad msg_id' # msg_id
# ^ We should make sure that the read ``msg_id`` is greater
# than our own ``msg_id``. However, under some circumstances
# (bad system clock/working behind proxies) this seems to not
# be the case, which would cause endless assertion errors.
assert reader.read_int() > 0, 'Bad length' # length
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# We could read length bytes and use those in a new reader to read
# the next TLObject without including the padding, but since the
# reader isn't used for anything else after this, it's unnecessary.
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return reader.tgread_object()