SocketServer在退出时不释放端口

Question

我对Python (2.7) socketserver有以下问题：

import wx
import socket
from SocketServer import BaseRequestHandler, ThreadingTCPServer
from threading import Thread
from wx.lib.pubsub import pub
from GUI import GUI

class LogHandler(BaseRequestHandler):
    def handle(self):
        data = self.request.recv(1024)
        wx.CallAfter(pub.sendMessage, 'logmsg', msg=data)
        self.request.close()

class MyTestGUI(GUI):
    def __init__(self):
        super(MyTestGUI, self).__init__(None)
        pub.subscribe(self.AppendLog, 'logmsg')

        self.LogServer = ThreadingTCPServer(('', 10010), LogHandler)
        self.LogServer.allow_reuse_address = True
        self.thd = Thread(target=self.LogServer.serve_forever)
        self.thd.daemon = True
        self.thd.start()

    def AppendLog(self, msg):
        # Append the mesage
        print(msg)

    def AppClose(self, event):
        self.LogServer.shutdown()
        self.LogServer.server_close()
        exit()

if __name__ == '__main__':
    app = wx.App()
    frame = MyTestGUI()
    frame.Show(True)
    app.MainLoop()

此服务器应接收来自设备的消息(在发送消息时关闭套接字)。在第一次运行时，代码运行正常，但在重新启动后，我得到了以下异常：

    self.LogServer = ThreadingTCPServer(('', 10010), LogHandler)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/SocketServer.py", line 420, in __init__
    self.server_bind()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/SocketServer.py", line 434, in server_bind
    self.socket.bind(self.server_address)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/socket.py", line 228, in meth
    return getattr(self._sock,name)(*args)
socket.error: [Errno 48] Address already in use

LogServer.allow_reuse_address = True / False，不会更改任何内容。

Answer 1

我在Python3.7.2中使用(非线程) socketserver.TCPServer实例时也遇到了同样的问题。(我在opensuse上使用anaconda，以防万一)

我的解决方案是：

在服务器初始化期间，我将__init__函数的第三个参数设置为false：

1. 我将__init__标志设置为True，只有在设置了此标志之后，才会调用.server_bind()和.server_activate()函数。

我认为重要的是在绑定和激活服务器之前设置bind_and_activate标志，因为如果TCPServer初始化期间的bind_and_activate参数为真或未设置，则TCPServer.__init__()将同时调用server_bind()和server_activate()函数。在这种情况下，我无法更改.allow_reuse_address标志的值-我可以从print()调用中看到它。

(请注意，下面的代码不起作用，因为其中缺少请求处理程序定义。我也使用超时，但这与问题无关)

def set_up_server_for_one_request(host, port, reqHandler, timeout = 600):
    ''' set up a server for one request. there is timeout as well.
    '''
        
    with socketserver.TCPServer((host, port), reqHandler, \
                                bind_and_activate= False) as serverInstance:  
                
        print('reuse  adress attribute before flag setting: ',\
              serverInstance.socket.getsockopt(socket.SOL_SOCKET,\
                                               socket.SO_REUSEADDR))#print flagVal before setting
        
        serverInstance.allow_reuse_address = True
        
        print('reuse  adress attribute after flag setting: ',\
              serverInstance.socket.getsockopt(socket.SOL_SOCKET, \
                                               socket.SO_REUSEADDR)) #print flagVal after setting
        
        print('server adress: ', serverInstance. server_address)
            
        serverInstance.server_bind()
        
        serverInstance.server_activate()
        
        serverInstance.timeout = timeout    #set server's timeout
        
        serverInstance.handle_request()
        
    print('server finished, and exits')
    
            

if __name__ == '__main__':
    
    set_up_server_for_one_request(host = 'localhost', port = 9998,\
                                  reqHandler = My_EchoRH, timeout = 20)