Python Client-Server 如何处理超时

Question

我有一个TCP客户端 - 服务器，其中客户端向服务器发送shell命令，服务器使用所述命令的输出进行响应。某些命令（如 date 或 cd）不起作用，因为它们是交互式的，我假设我的代码不处理它。每当我发送上述命令时，我的客户端似乎都挂起了，只是说发送...我的服务器从未收到任何东西。我想弄清楚如何处理这种情况，如果发送命令需要超过5秒的时间，客户端将导致超时，或者只是处理它并打印一条消息，指出命令未成功执行，同时保持客户端连接到服务器。这是我的代码客户：import socket# Clientsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  # creates TCP Socket# local host and portLOCAL_HOST = '127.0.0.1'PORT = 5313BUFFER_SIZE = 5000  # size of messagesock.settimeout(5)# connect socket to ip and portsock.connect((LOCAL_HOST, PORT))print("Connected to server\n")print("Enter quit to close connection\n")while True:    message = input("Please enter a command:\n")  # ask user to input message    if message == 'quit':        break    if len(message) == 0:        print("Please enter something")        message = input("Please enter a command:\n")    print("Sending %s" % message)    sock.send(str.encode(message))  # send message    command = str(sock.recv(BUFFER_SIZE), "utf-8")  # receive message    print("received %s" % command)print("closing connection with server")sock.close()服务器：import socketimport subprocess# Server# Some commands do not work such as cd. Date does not work on windows because it is interactive.# creates TCP socketsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)sock.settimeout(5)# port and server ip(localhost)LOCAL_HOST = ''PORT = 5313BUFFER_SIZE = 5000  # size of message# test connectionprint("Server starting up on %s with port number %s" % (LOCAL_HOST, PORT))# bind socket to ip and portsock.bind((LOCAL_HOST, PORT))# listen to socketsock.listen(1)

Answer 1

有多种方法可以做到这一点，但可能最简单的方法是调用subprocess.check_output（）方法，该方法允许您以秒为单位指定超时值，并且还返回子进程生成的文本，即：

[...]

while True:

    command = connection.recv(BUFFER_SIZE)  # receive message from client

    if not command:

        break

    command = command.decode("utf-8").strip()

    if len(command) > 0:

        try:

           output_as_string = subprocess.check_output(command, stderr=subprocess.STDOUT, shell=True, timeout=5.0).decode("utf-8")

        except subprocess.TimeoutExpired:

           output_as_string = "Sub-process timed out!\r\n"

        connection.send(str.encode("0:") + str.encode(output_as_string))

[...]