mirror of
https://github.com/LonamiWebs/Telethon.git
synced 2024-09-21 19:28:54 +03:00
65 lines
2.0 KiB
Python
65 lines
2.0 KiB
Python
import errno
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import struct
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from zlib import crc32
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from .common import Connection
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from ...errors import InvalidChecksumError
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from ...extensions import TcpClient
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class ConnectionTcpFull(Connection):
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"""
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Default Telegram mode. Sends 12 additional bytes and
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needs to calculate the CRC value of the packet itself.
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"""
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def __init__(self, *, loop, timeout, proxy=None):
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super().__init__(loop=loop, timeout=timeout, proxy=proxy)
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self._send_counter = 0
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self.conn = TcpClient(
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timeout=self._timeout, loop=self._loop, proxy=self._proxy
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)
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self.read = self.conn.read
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self.write = self.conn.write
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async def connect(self, ip, port):
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try:
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await self.conn.connect(ip, port)
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except OSError as e:
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if e.errno == errno.EISCONN:
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return # Already connected, no need to re-set everything up
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else:
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raise
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self._send_counter = 0
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def get_timeout(self):
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return self.conn.timeout
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def is_connected(self):
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return self.conn.is_connected
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async def close(self):
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self.conn.close()
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async def recv(self):
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packet_len_seq = await self.read(8) # 4 and 4
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packet_len, seq = struct.unpack('<ii', packet_len_seq)
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body = await self.read(packet_len - 8)
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checksum = struct.unpack('<I', body[-4:])[0]
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body = body[:-4]
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valid_checksum = crc32(packet_len_seq + body)
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if checksum != valid_checksum:
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raise InvalidChecksumError(checksum, valid_checksum)
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return body
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async def send(self, message):
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# https://core.telegram.org/mtproto#tcp-transport
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# total length, sequence number, packet and checksum (CRC32)
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length = len(message) + 12
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data = struct.pack('<ii', length, self._send_counter) + message
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crc = struct.pack('<I', crc32(data))
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self._send_counter += 1
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await self.write(data + crc)
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