如何让我的asyncio客户端调用套接字服务器并等待响应
我正在与asyncio.Protocol
服务器一起工作,其目的是让客户端调用服务器,但等待,直到服务器响应并且数据为在停止客户端循环之前返回。如何让我的asyncio客户端调用套接字服务器并等待响应
根据asyncio doc回声客户端和服务器:https://docs.python.org/3/library/asyncio-protocol.html#protocol-example-tcp-echo-server-and-client,transport.write(...)的结果在被调用时立即返回。
通过经验,呼吁loop.run_until_complete(coroutine)
失败RuntimeError: Event loop is running.
服务器的data_received()
方法运行asyncio.sleep(n)
没有任何效力,要么。
yield from asyncio.sleep(n)
and yield from asyncio.async(asyncio.sleep(n))
in data_received()
both the hang the server。
我的问题是,我如何让我的客户端在回馈控制之前等待服务器写回应?
我想永远不要直接使用传输/协议对。
asyncio具有用于高级编程的Streams API。
客户端代码可以是这样的:
@asyncio.coroutine
def communicate():
reader, writer = yield from asyncio.open_connection(HOST, PORT)
writer.write(b'data')
yield from writer.drain()
answer = yield from reader.read()
# process answer, maybe send new data back to server and wait for answer again
writer.close()
您不必更改客户端代码。
echo-client.py
#!/usr/bin/env python3.4
import asyncio
class EchoClient(asyncio.Protocol):
message = 'Client Echo'
def connection_made(self, transport):
transport.write(self.message.encode())
print('data sent: {}'.format(self.message))
def data_received(self, data):
print('data received: {}'.format(data.decode()))
def connection_lost(self, exc):
print('server closed the connection')
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()
技巧是你的代码(包括self.transport方法)放入一个协程,并使用wait_for()
方法,与yield from
声明语句的前面要求他们返回的值,或者说,这些需要一段时间才能完成:
echo-server.py
#!/usr/bin/env python3.4
import asyncio
class EchoServer(asyncio.Protocol):
def connection_made(self, transport):
peername = transport.get_extra_info('peername')
print('connection from {}'.format(peername))
self.transport = transport
def data_received(self, data):
print('data received: {}'.format(data.decode()))
fut = asyncio.async(self.sleeper())
result = asyncio.wait_for(fut, 60)
@asyncio.coroutine
def sleeper(self):
yield from asyncio.sleep(2)
self.transport.write("Hello World".encode())
self.transport.close()
loop = asyncio.get_event_loop()
coro = loop.create_server(EchoServer, '127.0.0.1', 8888)
server = loop.run_until_complete(coro)
print('serving on {}'.format(server.sockets[0].getsockname()))
try:
loop.run_forever()
except KeyboardInterrupt:
print("exit")
finally:
server.close()
loop.close()
拨打电话echo-server.py
然后echo-client.py
,客户端将等待2秒钟,如asyncio.sleep
确定,然后停止。
你想刚刚从服务器获取答案后关闭客户端?或者是其他东西? – 2014-09-06 09:42:11
是的,我希望客户端和服务器之间的功能就像典型的同步方法调用一样,尽管它是非阻塞的 – NuclearPeon 2014-09-07 21:51:57