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获取asyncio服务器以调用另一台服务器

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所以我修改了asyncio客户端和服务器的例子(在这里找到:https://docs.python.org/3/library/asyncio-protocol.html#protocol-example-tcp-echo-server-and-client),我想要的是client.py调用serverone.py,然后调用servertwo.py .

client.py

#!/usr/bin/env python3.4
import asyncio

class EchoClient(asyncio.Protocol):
    message = 'This is the Client'

    def connection_made(self, transport):
        transport.write(self.message.encode())

    def data_received(self, data):
        print('data received: {}'.format(data.decode()))

    def connection_lost(self, exc):
        asyncio.get_event_loop().stop()

loop = asyncio.get_event_loop()
coro = loop.create_connection(EchoClient, '127.0.0.1', 8888)
loop.run_until_complete(coro)
loop.run_forever()
loop.close()

serverone.py

#!/usr/bin/env python3.4

import asyncio

class EchoClient(asyncio.Protocol):
    message = 'Server One sending message'

    def connection_made(self, transport):
        transport.write(self.message.encode())

    def data_received(self, data):
        print('data received: {}'.format(data.decode()))

    def connection_lost(self, exc):
        asyncio.get_event_loop().stop()

class EchoServer(asyncio.Protocol):
    def connection_made(self, transport):
        peername = transport.get_extra_info('peername')
        self.transport = transport

    def data_received(self, data):
        loop = asyncio.get_event_loop()
        coro = loop.create_connection(EchoClient, '127.0.0.1', 8889)
        loop.run_until_complete(coro)
        # close the socket
        self.transport.close()
        loop.close()

loop = asyncio.get_event_loop()
coro = loop.create_server(EchoServer, '127.0.0.1', 8888)
server = loop.run_until_complete(coro)
try:
    loop.run_forever()
except KeyboardInterrupt:
    print("exit")
finally:
    server.close()
    loop.close()

servertwo.py

#!/usr/bin/env python3.4

import asyncio

class EchoServer(asyncio.Protocol):
    def connection_made(self, transport):
        peername = transport.get_extra_info('peername')
        self.transport = transport

    def data_received(self, data):
        print('data received: {}'.format(data.decode()))
        self.transport.write(data)
        # close the socket
        self.transport.close()

loop = asyncio.get_event_loop()
coro = loop.create_server(EchoServer, '127.0.0.1', 8889)
server = loop.run_until_complete(coro)
try:
    loop.run_forever()
except KeyboardInterrupt:
    print("exit")
finally:
    server.close()
    loop.close()

我在终端中启动 servertwo.pyserverone.py ,然后调用 client.py . 事情部分奏效;客户端确实调用了serverone,它调用了servertwo,但是serverone失败并出现此错误:

Exception in callback <bound method _SelectorSocketTransport._read_ready of <asyncio.selector_events._SelectorSocketTransport object at 0x7fbf4453b048>>()
handle: Handle(<bound method _SelectorSocketTransport._read_ready of <asyncio.selector_events._SelectorSocketTransport object at 0x7fbf4453b048>>, ())
Traceback (most recent call last):
  File "/usr/lib64/python3.4/asyncio/events.py", line 39, in _run
    self._callback(*self._args)
  File "/usr/lib64/python3.4/asyncio/selector_events.py", line 458, in _read_ready
    self._protocol.data_received(data)
  File "./serverone.py", line 25, in data_received
    loop.run_until_complete(coro)
  File "/usr/lib64/python3.4/asyncio/base_events.py", line 203, in run_until_complete
    self.run_forever()
  File "/usr/lib64/python3.4/asyncio/base_events.py", line 179, in run_forever
    raise RuntimeError('Event loop is running.')
RuntimeError: Event loop is running.

该文档有点卡住了 . 我应该使用 asyncio.async 拨打电话吗?我正确地接近了这个问题吗?

如何修复或避免 RuntimeError

1 回答

  • 3

    您可以使用asyncio.async来安排 create_connection 返回的协程由事件循环运行,然后使用 asyncio.Futureadd_done_callback 方法(更具体地说,asyncio.Taskasync 返回以在协程完成后关闭循环:

    class EchoServer(asyncio.Protocol):
        def connection_made(self, transport):
            peername = transport.get_extra_info('peername')
            self.transport = transport
    
        def data_received(self, data):
            loop = asyncio.get_event_loop()
            coro = loop.create_connection(EchoClient, '127.0.0.1', 8890)
            fut = asyncio.async(coro)
            fut.add_done_callback(self.shutdown)
    
        def shutdown(self, *args):
            self.transport.close()
            loop.stop()
    

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