Telethon/telethon/network/connection/connection.py

117 lines
3.5 KiB
Python

import abc
import asyncio
class Connection(abc.ABC):
"""
The `Connection` class is a wrapper around ``asyncio.open_connection``.
Subclasses are meant to communicate with this class through a queue.
This class provides a reliable interface that will stay connected
under any conditions for as long as the user doesn't disconnect or
the input parameters to auto-reconnect dictate otherwise.
"""
# TODO Support proxy. Support timeout?
def __init__(self, ip, port, *, loop):
self._ip = ip
self._port = port
self._loop = loop
self._reader = None
self._writer = None
self._disconnected = asyncio.Event(loop=loop)
self._disconnected.set()
self._send_task = None
self._recv_task = None
self._send_queue = asyncio.Queue(1)
self._recv_queue = asyncio.Queue(1)
async def connect(self):
"""
Establishes a connection with the server.
"""
self._reader, self._writer = await asyncio.open_connection(
self._ip, self._port, loop=self._loop)
self._disconnected.clear()
self._send_task = self._loop.create_task(self._send_loop())
self._recv_task = self._loop.create_task(self._recv_loop())
def disconnect(self):
"""
Disconnects from the server.
"""
self._disconnected.set()
self._send_task.cancel()
self._recv_task.cancel()
self._writer.close()
def clone(self):
"""
Creates a clone of the connection.
"""
return self.__class__(self._ip, self._port, loop=self._loop)
def send(self, data):
"""
Sends a packet of data through this connection mode.
This method returns a coroutine.
"""
return self._send_queue.put(data)
def recv(self):
"""
Receives a packet of data through this connection mode.
This method returns a coroutine.
"""
return self._recv_queue.get()
# TODO Get/put to the queue with cancellation
async def _send_loop(self):
"""
This loop is constantly popping items off the queue to send them.
"""
while not self._disconnected.is_set():
self._send(await self._send_queue.get())
await self._writer.drain()
# TODO Handle IncompleteReadError and InvalidChecksumError
async def _recv_loop(self):
"""
This loop is constantly putting items on the queue as they're read.
"""
while not self._disconnected.is_set():
try:
data = await self._recv()
except asyncio.IncompleteReadError:
if not self._disconnected.is_set():
raise
else:
await self._recv_queue.put(data)
@abc.abstractmethod
def _send(self, data):
"""
This method should be implemented differently under each
connection mode and serialize the data into the packet
the way it should be sent through `self._writer`.
"""
raise NotImplementedError
@abc.abstractmethod
async def _recv(self):
"""
This method should be implemented differently under each
connection mode and deserialize the data from the packet
the way it should be read from `self._reader`.
"""
raise NotImplementedError
def __str__(self):
return '{}:{}/{}'.format(
self._ip, self._port,
self.__class__.__name__.replace('Connection', '')
)