Edit: _asyncio_backend.py
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license """asyncio library query support""" import asyncio import socket import sys import dns._asyncbackend import dns._features import dns.exception import dns.inet _is_win32 = sys.platform == "win32" def _get_running_loop(): try: return asyncio.get_running_loop() except AttributeError: # pragma: no cover return asyncio.get_event_loop() class _DatagramProtocol: def __init__(self): self.transport = None self.recvfrom = None def connection_made(self, transport): self.transport = transport def datagram_received(self, data, addr): if self.recvfrom and not self.recvfrom.done(): self.recvfrom.set_result((data, addr)) def error_received(self, exc): # pragma: no cover if self.recvfrom and not self.recvfrom.done(): self.recvfrom.set_exception(exc) def connection_lost(self, exc): if self.recvfrom and not self.recvfrom.done(): if exc is None: # EOF we triggered. Is there a better way to do this? try: raise EOFError("EOF") except EOFError as e: self.recvfrom.set_exception(e) else: self.recvfrom.set_exception(exc) def close(self): self.transport.close() async def _maybe_wait_for(awaitable, timeout): if timeout is not None: try: return await asyncio.wait_for(awaitable, timeout) except asyncio.TimeoutError: raise dns.exception.Timeout(timeout=timeout) else: return await awaitable class DatagramSocket(dns._asyncbackend.DatagramSocket): def __init__(self, family, transport, protocol): super().__init__(family, socket.SOCK_DGRAM) self.transport = transport self.protocol = protocol async def sendto(self, what, destination, timeout): # pragma: no cover # no timeout for asyncio sendto self.transport.sendto(what, destination) return len(what) async def recvfrom(self, size, timeout): # ignore size as there's no way I know to tell protocol about it done = _get_running_loop().create_future() try: assert self.protocol.recvfrom is None self.protocol.recvfrom = done await _maybe_wait_for(done, timeout) return done.result() finally: self.protocol.recvfrom = None async def close(self): self.protocol.close() async def getpeername(self): return self.transport.get_extra_info("peername") async def getsockname(self): return self.transport.get_extra_info("sockname") async def getpeercert(self, timeout): raise NotImplementedError class StreamSocket(dns._asyncbackend.StreamSocket): def __init__(self, af, reader, writer): super().__init__(af, socket.SOCK_STREAM) self.reader = reader self.writer = writer async def sendall(self, what, timeout): self.writer.write(what) return await _maybe_wait_for(self.writer.drain(), timeout) async def recv(self, size, timeout): return await _maybe_wait_for(self.reader.read(size), timeout) async def close(self): self.writer.close() async def getpeername(self): return self.writer.get_extra_info("peername") async def getsockname(self): return self.writer.get_extra_info("sockname") async def getpeercert(self, timeout): return self.writer.get_extra_info("peercert") if dns._features.have("doh"): import anyio import httpcore import httpcore._backends.anyio import httpx _CoreAsyncNetworkBackend = httpcore.AsyncNetworkBackend _CoreAnyIOStream = httpcore._backends.anyio.AnyIOStream from dns.query import _compute_times, _expiration_for_this_attempt, _remaining class _NetworkBackend(_CoreAsyncNetworkBackend): def __init__(self, resolver, local_port, bootstrap_address, family): super().__init__() self._local_port = local_port self._resolver = resolver self._bootstrap_address = bootstrap_address self._family = family if local_port != 0: raise NotImplementedError( "the asyncio transport for HTTPX cannot set the local port" ) async def connect_tcp( self, host, port, timeout, local_address, socket_options=None ): # pylint: disable=signature-differs addresses = [] _, expiration = _compute_times(timeout) if dns.inet.is_address(host): addresses.append(host) elif self._bootstrap_address is not None: addresses.append(self._bootstrap_address) else: timeout = _remaining(expiration) family = self._family if local_address: family = dns.inet.af_for_address(local_address) answers = await self._resolver.resolve_name( host, family=family, lifetime=timeout ) addresses = answers.addresses() for address in addresses: try: attempt_expiration = _expiration_for_this_attempt(2.0, expiration) timeout = _remaining(attempt_expiration) with anyio.fail_after(timeout): stream = await anyio.connect_tcp( remote_host=address, remote_port=port, local_host=local_address, ) return _CoreAnyIOStream(stream) except Exception: pass raise httpcore.ConnectError async def connect_unix_socket( self, path, timeout, socket_options=None ): # pylint: disable=signature-differs raise NotImplementedError async def sleep(self, seconds): # pylint: disable=signature-differs await anyio.sleep(seconds) class _HTTPTransport(httpx.AsyncHTTPTransport): def __init__( self, *args, local_port=0, bootstrap_address=None, resolver=None, family=socket.AF_UNSPEC, **kwargs, ): if resolver is None and bootstrap_address is None: # pylint: disable=import-outside-toplevel,redefined-outer-name import dns.asyncresolver resolver = dns.asyncresolver.Resolver() super().__init__(*args, **kwargs) self._pool._network_backend = _NetworkBackend( resolver, local_port, bootstrap_address, family ) else: _HTTPTransport = dns._asyncbackend.NullTransport # type: ignore class Backend(dns._asyncbackend.Backend): def name(self): return "asyncio" async def make_socket( self, af, socktype, proto=0, source=None, destination=None, timeout=None, ssl_context=None, server_hostname=None, ): loop = _get_running_loop() if socktype == socket.SOCK_DGRAM: if _is_win32 and source is None: # Win32 wants explicit binding before recvfrom(). This is the # proper fix for [#637]. source = (dns.inet.any_for_af(af), 0) transport, protocol = await loop.create_datagram_endpoint( _DatagramProtocol, source, family=af, proto=proto, remote_addr=destination, ) return DatagramSocket(af, transport, protocol) elif socktype == socket.SOCK_STREAM: if destination is None: # This shouldn't happen, but we check to make code analysis software # happier. raise ValueError("destination required for stream sockets") (r, w) = await _maybe_wait_for( asyncio.open_connection( destination[0], destination[1], ssl=ssl_context, family=af, proto=proto, local_addr=source, server_hostname=server_hostname, ), timeout, ) return StreamSocket(af, r, w) raise NotImplementedError( "unsupported socket " + f"type {socktype}" ) # pragma: no cover async def sleep(self, interval): await asyncio.sleep(interval) def datagram_connection_required(self): return False def get_transport_class(self): return _HTTPTransport async def wait_for(self, awaitable, timeout): return await _maybe_wait_for(awaitable, timeout)
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