Python连续TCP连接 [英] Python continuous TCP connection

问题描述

我是套接字编程的新手，正在尝试重新使用python。我想编写一个简单的TCP程序，该程序将持续保持连接，直到达到某种最终状态为止，在这种情况下，客户端将发送关闭。

I'm new to socket programming and trying to get back into python. I wanted to write a simple TCP program which will continuously maintain a connection until some end state is reached, in this case "close" is sent by the client.

第一次迭代就可以了，但是它冻结了我发送的第二个东西，我不确定为什么。有人可以解释为什么我的程序死机或如何更好地实现吗？

This works fine for the first iteration, but it freezes on the second thing I send and I'm not sure why. Could someone please explain why my program freezes or how better implement this?

TCPServer.py

TCPServer.py

from socket import *
serverPort = 12000
serverSocket = socket(AF_INET, SOCK_STREAM)
serverSocket.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
serverSocket.bind(('', serverPort))
serverSocket.listen(1)
print('The server is ready to recieve')

while True:
    connectionSocket, addr = serverSocket.accept()
    sentence = connectionSocket.recv(1024).decode()
    if(sentence == "close"):
        connectionSocket.close()
    capSentence = sentence.upper()
    connectionSocket.send(capSentence.encode())

TCPClient.py

TCPClient.py

from socket import *
serverName = 'localhost'
serverPort = 12000
clientSocket = socket(AF_INET, SOCK_STREAM)
clientSocket.connect((serverName, serverPort))
while(1):
    sentence = raw_input('input sentence: ')
    if(sentence == "close"):
        break
    clientSocket.send(sentence.encode())
    retSentence = clientSocket.recv(1024)
    print('From server; ', retSentence.decode())

clientSocket.close()

推荐答案

服务器存在多个问题。我会尝试指出我所看到的。

There are multiple problems with the server. I'll try to point out what I see.

它冻结了您发送的第二件事，因为如果服务器再次尝试从客户端套接字读取，则服务器永远不会尝试收到的数据不等于关闭 。您需要另一个循环来完成此操作，例如：

It freezes on the second thing you send because the server never attempts to read from the client socket a second time if the received data is not equal to "close". You need another loop to accomplish this, such as:

while True:
    connectionSocket, addr = serverSocket.accept()

    while True:
        sentence = connectionSocket.recv(1024).decode()
        if sentence == "close": break
        capSentence = sentence.upper()
        connectionSocket.send(capSentence.encode())

    connectionSocket.close()

另外，请注意，服务器同步运行循环，因此直到第一个连接关闭，它才能接受第二个连接。

Additionally, note that the server runs through the loops synchronously, and so it cannot accept a second connection until the first one is closed.

最后，您缺少错误处理代码。如果客户端过早断开连接，则整个服务器将崩溃。

Finally, you are missing error handling code. The whole server will crash if a client prematurely disconnects.

如果您的目标是让服务器仅处理单个连接，然后终止，最简单的解决方案是将 accept（）调用移到主循环之外（否则，请等待 new （每次迭代）。

If your goal is to have the server only handle a single connection and then terminate, the simplest solution is to move the accept() call outside of the main loop (otherwise you wait for a new connection on each iteration).

connectionSocket, addr = serverSocket.accept()

# Destroy the server socket; we don't need it anymore since we are not
# accepting any connections beyond this point.
serverSocket.close()

while True:
    sentence = connectionSocket.recv(1024).decode()
    if(sentence == "close"):
        connectionSocket.close()
        break
    capSentence = sentence.upper()
    connectionSocket.send(capSentence.encode())

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