asyncio.run_直到完成未来是s

Question

我在python3中学习asyncio，我编写了一个简单的RPC服务器和客户机来学习，但是当我用asyncio.run_直到完成，它在设置好未来后阻塞，代码如下，检查main部分。我使用的是python3.4.2

import asyncio
import struct

_req_struct = struct.Struct('<4i')
_req_size = _req_struct.size

_resp_struct = struct.Struct('<3i')
_resp_size = _resp_struct.size


class SimpleRPCClient(asyncio.Protocol):
    _transport = None

    def __init__(self):
        self._pendings = {}
        self.seq_id = 0
        self._cached = bytearray()

    def connection_made(self, transport):
        """
        First event, create ref to transport
        """
        self._transport = transport

    def send(self, data):
        """
        proxy to transport.write
        """
        self._transport.write(data)

    def data_received(self, data):
        c = self._cached
        c.extend(data)
        cursor = 0
        while len(self._cached) >= (cursor + _resp_size):
            rid, status, result = _resp_struct.unpack(
                c[cursor:cursor + _resp_size])
            if rid in self._pendings:
                f = self._pendings.pop(rid)
                f.set_result(result)
                print("future result: ", f.result())

    def calc(self, oprand, op1, op2):
        rid = self.seq_id
        self.seq_id += 1
        future = asyncio.Future()
        self._pendings[rid] = future
        self.send(_req_struct.pack(rid, oprand, op1, op2))
        return future


if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    host = "127.0.0.1"
    port = 8087
    _tr, client = loop.run_until_complete(loop.create_connection(
        SimpleRPCClient,
        host,
        port))
    f = client.calc(1, 3, 5)
    loop.run_until_complete(f)
    print("final result: ", f.result())

函数是计算3+5， 当我运行这个程序时，它会正确地显示结果，如

future result: 8

但是程序块之后，就再也没有显示出最终的结果，未来设置成功但是函数不返回，这是为什么呢？在

如果您想运行服务器端，请将其附在下面

^{pr2}$

Answer 1

在你的循环中已接收SimpleRPCClient.data_（）方法永不停止。在