UDP服务器中的asyncio.sleep不起作用[重复]

Question

我正在使用asyncio UDP server example 并希望在datagram_received 方法中获得sleep。

import asyncio

class EchoServerProtocol:
    def connection_made(self, transport):
        self.transport = transport

    def datagram_received(self, data, addr):
        message = data.decode()
        print('Received %r from %s' % (message, addr))
        # Sleep
        await asyncio.sleep(1)
        print('Send %r to %s' % (message, addr))
        self.transport.sendto(data, addr)

loop = asyncio.get_event_loop()
print("Starting UDP server")
# One protocol instance will be created to serve all client requests
listen = loop.create_datagram_endpoint(EchoServerProtocol,
                                       local_addr=('127.0.0.1', 9999))
transport, protocol = loop.run_until_complete(listen)

try:
    loop.run_forever()
except KeyboardInterrupt:
    pass

transport.close()
loop.close()

这会失败，并在睡眠行 (Python 3.5.1) 上显示 SyntaxError。使用time.sleep 显然不起作用，因为它会阻止接收任何其他数据报。有关如何解决此问题的任何提示？

我们的目标是用真正的非阻塞 I/O 调用替换这个 sleep。

Answer 1

似乎await 必须生活在async def（协程）中。为此，您必须通过asyncio.ensure_future 拨打电话。

def datagram_received(self, data, addr):
    asyncio.ensure_future(self.reply(data, addr))

async def reply(self, data, addr):
    await asyncio.sleep(1)
    self.transport.sendto(data, addr)