相关疑难解决方法(0)

PEP 0492增加了新的__await__魔法.实现此方法的对象变为类似未来的对象,可以等待使用await.很明显:

import asyncio


class Waiting:
    def __await__(self):
        yield from asyncio.sleep(2)
        print('ok')

async def main():
    await Waiting()

if __name__ == "__main__":
    loop = asyncio.get_event_loop()
    loop.run_until_complete(main())

好的,但如果我想调用一些已async def定义的函数而不是asyncio.sleep？我不能使用await因为__await__不是async函数,我无法使用yield from因为本机协同程序需要await表达式:

async def new_sleep():
    await asyncio.sleep(2)

class Waiting:
    def __await__(self):
        yield from new_sleep()  # this is TypeError
        await new_sleep()  # this is SyntaxError
        print('ok')

我该如何解决？

我想通过asyncio和连接到websocket websockets,格式如下所示.我怎么能做到这一点？

from websockets import connect


class EchoWebsocket:

    def __init__(self):
        self.websocket = self._connect()

    def _connect(self):
        return connect("wss://echo.websocket.org")

    def send(self, message):
        self.websocket.send(message)

    def receive(self):
        return self.websocket.recv()

echo = EchoWebsocket()
echo.send("Hello!")
print(echo.receive())  # "Hello!"