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我想在 app.py 上使用 asyncio 创建两个协议(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) 两种协议进行通信:互相调用方法。这仅适用于第一个连接。如果 TcpClient 重新连接,它不能再次发送字符串“send to tcp”。来自 UdpServer。我检查print(self)并 TcpClient 创建了一个新实例,旧实例仍然存在但没有连接,但我不知道如何重构它。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 并尝试重新连接,以此类推。我尝试使用call_later()asyncio,但我认为有一种本地方法可以做到这一点,而不是一种技巧。
c)当我启动 app.py 时,如果 TcpClient 无法连接,我想在 5 秒后尝试重新连接,依此类推。我不知道该怎么做。

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

只是说我尝试过:
1)当我启动 app.py 并且 server.py 关闭时,app.py 不要重试。
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,但我不能更多地在新实例上连接其他方法并发送字符串“send to tcp”。到 server.py,只是旧的,没有更多的连接。
3)如果我asyncio.async()改用,run_until_complete()我不能从其他协议调用方法。

我把 app.py 和 server.py 放在这里,所以你可以复制并运行测试。

ncat localhost 9000 -u -v用来发送字符串“send to tcp.”。该字符串需要打印在 UdpServer 类上并传递给 TcpClient 类的方法 send_data_to_tcp,该方法会将字符串发送到 server.py。<- 这在第一次重新连接 tcpClient 后不起作用。

我正在使用 Python 3.4.0。

太感谢了。

应用程序.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()

服务器.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()
4

1 回答 1

13

你真的只需要一些小的修复。首先,我编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一切:

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()

下一部分是在 app.py 启动后处理服务器宕机/恢复。我们需要修复tcp_client_disconnectedconnect_client_tcp妥善处理:

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)

有趣的是connect_client_tcp。您的原始版本有两个问题:

  1. client_tcp直接分配给 的结果asyncio.async(coro),这意味着client_tcp分配给asyncio.Task. 那不是你想要的。你想client_tcp被分配到完成的结果asyncio.Task。我们通过使用它完成后task.add_done_callback分配client_tcp给结果来实现这Task一点。

  2. 您忘记global client_tcp了方法的顶部。没有它,你只是创建了一个名为 的局部变量client_tcp,它在connect_client_tcp.

一旦这些问题得到解决,我就可以随时运行app.py、启动/停止serv.py,但始终可以看到所有消息从所有三个组件一起运行时ncat正确传递。serv.py

这是完整的app.py,便于复制/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()
于 2014-09-23T21:00:56.717 回答