Question

我想在app.py上创建两个带有asyncio的协议（TcpClient和UdpServer），其中TcpClient将与server.py和UdpServer作为UDP服务器建立持久连接：

我需要什么：
a）两种通信协议：相互调用方法。这只是在第一个连接上工作。如果TcpClient重新连接，则无法再次发送字符串“send to tcp”。来自UdpServer。我检查print(self)并且TcpClient创建一个新实例，旧的仍然存在，但没有连接，但我不知道如何重构。我认为我以错误的方式使用asyncio b）当TcpClient与server.py断开连接时，等待5s并再次尝试重新连接，依此类推。我尝试使用as call_later() asyncio，但我认为有一种本地方式可以做到这一点而不是技巧。
c）当我启动app.py并且如果TcpClient无法连接时，我想尝试在5s后重新连接，依此类推。我不知道该怎么做。

这是我的app.py server.py的示例测试。 server.py仅用于测试 - 这将是另一种语言。

只是说我尝试了什么：
1）当我启动app.py并且server.py关闭时，app.py不会重试 2）当app.py连接到server.py并且服务器关闭并快速启动时，TcpClient重新连接，但我无法在新实例上相互连接方法并发送字符串“send to tcp”。到server.py，只是旧的，没有更多的连接 3）如果我使用asyncio.async()代替run_until_complete()我无法从其他协议中调用方法。

我把app.py和server.py放在这里，所以你可以复制并运行测试。

我使用ncat localhost 9000 -u -v发送字符串“send to tcp。”。此字符串需要打印在UdpServer类上并传递给TcpClient类上的方法send_data_to_tcp，此方法将字符串发送到server.py。＆lt; - 首次重新连接tcpClient后，这不起作用。

我正在使用Python 3.4.0。

非常感谢你。

app.py：

import asyncio

#TCP client
class TcpClient(asyncio.Protocol):
    message = 'Testing'

    def connection_made(self, transport):
        self.transport = transport
        self.transport.write(self.message.encode())
        print('data sent: {}'.format(self.message))
        server_udp[1].tcp_client_connected()


    def data_received(self, data):
        self.data = format(data.decode())
        print('data received: {}'.format(data.decode()))
        if self.data == 'Testing':
            server_udp[1].send_data_to_udp(self.data)

    def send_data_to_tcp(self, data):
        self.transport.write(data.encode())

    def connection_lost(self, exc):
        msg = 'Connection lost with the server...'
        info = self.transport.get_extra_info('peername')
        server_udp[1].tcp_client_disconnected(msg, info)


#UDP Server
class UdpServer(asyncio.DatagramProtocol):

    CLIENT_TCP_TIMEOUT = 5.0

    def __init__(self):
        self.client_tcp_timeout = None

    def connection_made(self, transport):
        print('start', transport)
        self.transport = transport

    def datagram_received(self, data, addr):
        self.data = data.strip()
        self.data = self.data.decode()
        print('Data received:', self.data, addr)
        if self.data == 'send to tcp.':
            client_tcp[1].send_data_to_tcp(self.data)

    def connection_lost(self, exc):
        print('stop', exc)

    def send_data_to_udp(self, data):
        print('Receiving on UDPServer Class: ', (data))

    def connect_client_tcp(self):
        coro = loop.create_connection(TcpClient, 'localhost', 8000)
        #client_tcp = loop.run_until_complete(coro)
        client_tcp = asyncio.async(coro)

    def tcp_client_disconnected(self, data, info):
        print(data)
        self.client_tcp_info = info
        self.client_tcp_timeout = asyncio.get_event_loop().call_later(self.CLIENT_TCP_TIMEOUT, self.connect_client_tcp)

    def tcp_client_connected(self):
        if self.client_tcp_timeout:
            self.client_tcp_timeout.cancel()
            print('call_later cancel.')

loop = asyncio.get_event_loop()

#UDP Server
coro = loop.create_datagram_endpoint(UdpServer, local_addr=('localhost', 9000)) 
#server_udp = asyncio.Task(coro)
server_udp = loop.run_until_complete(coro)


#TCP client
coro = loop.create_connection(TcpClient, 'localhost', 8000)
#client_tcp = asyncio.async(coro)
client_tcp = loop.run_until_complete(coro)

loop.run_forever()

server.py：

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()))
        self.transport.write(data)

        # close the socket
        #self.transport.close()

    #def connection_lost(self):
    #    print('server closed the connection')



loop = asyncio.get_event_loop()
coro = loop.create_server(EchoServer, 'localhost', 8000)
server = loop.run_until_complete(coro)
print(server)
print(dir(server))
print(dir(server.sockets))

print('serving on {}'.format(server.sockets[0].getsockname()))

try:
    loop.run_forever()
except KeyboardInterrupt:
    print("exit")
finally:
    server.close()
    loop.close()

Answer 1

你真的只需要一些小修正。首先，我写了一个协程来处理连接重试：

@asyncio.coroutine
def do_connect():
    global tcp_server  # Make sure we use the global tcp_server
    while True:
        try:
            tcp_server = yield from loop.create_connection(TcpClient, 
                                                           'localhost', 8000)
        except OSError:
            print("Server not up retrying in 5 seconds...")
            yield from asyncio.sleep(5)
        else:
            break

然后我们用它来启动所有事情：

loop = asyncio.get_event_loop()

#UDP Server
coro = loop.create_datagram_endpoint(UdpServer, local_addr=('localhost', 9000)) 
server_udp = loop.run_until_complete(coro)

#TCP client
loop.run_until_complete(do_connect())

loop.run_forever()

下一篇文章是在app.py启动后处理服务器关闭/返回。我们需要修复tcp_client_disconnected和connect_client_tcp才能正确处理：

def connect_client_tcp(self):
    global client_tcp
    task = asyncio.async(do_connect())
    def cb(result):
        client_tcp = result
    task.add_done_callback(cb)

def tcp_client_disconnected(self, data, info):
    print(data)
    self.client_tcp_info = info
    self.client_tcp_timeout = loop.call_later(self.CLIENT_TCP_TIMEOUT, self.connect_client_tcp)

有趣的作品是connect_client_tcp。您的原始版本有两个问题：

您将client_tcp直接分配给asyncio.async(coro)的结果，这意味着client_tcp已分配给asyncio.Task。那不是你想要的;您希望将client_tcp分配给已完成的asyncio.Task的结果。我们通过task.add_done_callback将client_tcp分配给Task完成后的结果来实现这一目标。
您忘记了方法顶部的global client_tcp。如果没有这个，你只需要创建一个名为client_tcp的局部变量，该变量在connect_client_tcp的末尾被抛弃。

修复这些问题后，我可以随时运行app.py，启动/停止serv.py，但始终可以看到所有邮件从ncat正确传递到serv.py {1}}当所有三个组件一起运行时。

这里有完整的app.py，方便复制/粘贴：

import asyncio

#TCP client
class TcpClient(asyncio.Protocol):
    message = 'Testing'

    def connection_made(self, transport):
        self.transport = transport
        self.transport.write(self.message.encode())
        print('data sent: {}'.format(self.message))
        server_udp[1].tcp_client_connected()


    def data_received(self, data):
        self.data = format(data.decode())
        print('data received: {}'.format(data.decode()))
        if self.data == 'Testing':
            server_udp[1].send_data_to_udp(self.data)

    def send_data_to_tcp(self, data):
        self.transport.write(data.encode())

    def connection_lost(self, exc):
        msg = 'Connection lost with the server...'
        info = self.transport.get_extra_info('peername')
        server_udp[1].tcp_client_disconnected(msg, info)


#UDP Server
class UdpServer(asyncio.DatagramProtocol):

    CLIENT_TCP_TIMEOUT = 5.0

    def __init__(self):
        self.client_tcp_timeout = None

    def connection_made(self, transport):
        print('start', transport)
        self.transport = transport

    def datagram_received(self, data, addr):
        self.data = data.strip()
        self.data = self.data.decode()
        print('Data received:', self.data, addr)
        if self.data == 'send to tcp.':
            client_tcp[1].send_data_to_tcp(self.data)

    def connection_lost(self, exc):
        print('stop', exc)

    def send_data_to_udp(self, data):
        print('Receiving on UDPServer Class: ', (data))

    def connect_client_tcp(self):
        global client_tcp
        coro = loop.create_connection(TcpClient, 'localhost', 8000)
        task = asyncio.async(do_connect())
        def cb(result):
            client_tcp = result
        task.add_done_callback(cb)

    def tcp_client_disconnected(self, data, info):
        print(data)
        self.client_tcp_info = info
        self.client_tcp_timeout = loop.call_later(self.CLIENT_TCP_TIMEOUT, self.connect_client_tcp)

    def tcp_client_connected(self):
        if self.client_tcp_timeout:
            self.client_tcp_timeout.cancel()
            print('call_later cancel.')

@asyncio.coroutine
def do_connect():
    global client_tcp
    while True:
        try:
            client_tcp = yield from loop.create_connection(TcpClient, 'localhost', 8000)
        except OSError:
            print("Server not up retrying in 5 seconds...")
            yield from asyncio.sleep(1)
        else:
            break

loop = asyncio.get_event_loop()

#UDP Server
coro = loop.create_datagram_endpoint(UdpServer, local_addr=('localhost', 9000))
server_udp = loop.run_until_complete(coro)

#TCP client
loop.run_until_complete(do_connect())

loop.run_forever()

如何在asyncio上重新连接套接字？

app.py：

server.py：

1 个答案: