Python套接字網絡-ValueError：list.remove（x）：x不在列表中

Question

我是python的新手，請耐心等待，我基本上有一個有關套接字網絡的腳本，有時在運行該腳本時遇到以下錯誤：

Traceback (most recent call last):
  File "socks", line 293, in <module>
    server.main_loop()
  File "socks", line 210, in main_loop
    self.on_close()
  File "socks", line 237, in on_close
    self.input_list.remove(self.s)
ValueError: list.remove(x): x not in list

這是我擁有的腳本：

class TheServer:
    input_list = []
    channel = {}
    channel_ = {}
    request = {}

    def __init__(self, host, port):
        self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        self.server.bind((host, port))
        self.server.listen(200)

    def main_loop(self):
        self.input_list.append(self.server)
        while 1:
            ss = select.select
            inputready, outputready, exceptready = ss(self.input_list, [], [])
            for self.s in inputready:
                if self.s == self.server:
                    self.on_accept()
                    break
                try:
                    self.netdata = self.s.recv(buffer_size)
                except Exception, e:
                    self.netdata =''
                if len(self.netdata) == 0:
                    self.on_close()
                else:
                    if cmp(self.channel[self.s],self.channel_[self.s]):
                        self.on_outbounddata()
                    else:
                        self.on_execute()

    def on_accept(self):
        forward = Forward().start(forward_to[0], forward_to[1])
        clientsock, clientaddr = self.server.accept()
        if forward:
            self.input_list.append(clientsock)
            self.input_list.append(forward)
            self.channel[clientsock] = forward
            self.channel[forward] = clientsock
            self.channel_[clientsock] = forward
            self.channel_[forward] = forward
        else:
            waktu = datetime.datetime.strftime(datetime.datetime.now(), '%H:%M:%S')
            with open('/www/dial.log', 'a') as file:
              file.write(str(waktu) + " Proxy " + str(forward_to[0]) + ":" + str(forward_to[1]) + " isn't responding\n")
              file.close()
            print "Proxy " + str(forward_to[0]) + ":" + str(forward_to[1]) + " isn't responding"
            print "Closing connection with client side", clientaddr
            clientsock.close()

    def on_close(self):
        self.input_list.remove(self.s)
        self.input_list.remove(self.channel[self.s])
        out = self.channel[self.s]
        self.channel[out].close()  
        self.channel_[out].close() 
        self.channel[self.s].close()
        self.channel_[self.s].close()
        del self.channel[out]
        del self.channel_[out]
        del self.channel[self.s]
        del self.channel_[self.s]



    def on_execute(self):
        netdata = self.netdata

您認為上述腳本有什么問題？ 每當遇到該錯誤時，我都必須手動重新啟動腳本，這讓我感到沮喪。

更新：

我嘗試了@Moses的建議，

def on_close(self):
    try:
      self.input_list.remove(self.s)
    except ValueError:
      print "self.s is not in the list"
    self.input_list.remove(self.channel[self.s])
    out = self.channel[self.s]
    self.channel[out].close()  
    self.channel_[out].close() 
    self.channel[self.s].close()
    self.channel_[self.s].close()

我以為它解決了錯誤，但是后來我明白了：

Traceback (most recent call last):
  File "socks", line 296, in <module>
    server.main_loop()
  File "socks", line 210, in main_loop
    self.on_close()
  File "socks", line 241, in on_close
    self.input_list.remove(self.channel[self.s])
KeyError: <socket._socketobject object at 0x7f0669e93a60>

更新2：我修改了腳本，就像這樣

def on_close(self):
    try:
      self.input_list.remove(self.s)
    except ValueError:
      print "self.s is not in the list"
      pass
    self.input_list.remove(self.channel.get(self.s, None))
    out = self.channel[self.s]
    self.channel[out].close()  
    self.channel_[out].close() 
    self.channel[self.s].close()
    self.channel_[self.s].close()
    del self.channel[out]
    del self.channel_[out]
    del self.channel[self.s]
    del self.channel_[self.s]

而且我仍然收到此錯誤：

self.s is not in the list
Traceback (most recent call last):
  File "socks", line 296, in <module>
    try:
  File "socks", line 210, in main_loop
    self.on_close()
  File "socks", line 241, in on_close
    pass
ValueError: list.remove(x): x not in list

Answer 1

在嘗試刪除或僅使用try-except之前，請檢查列表中是否存在您所擁有的項目

if item in lst:
    lst.remove(item)
else:
    pass # you may print some message or log something

# OR

try:
    lst.remove(item)
except ValueError:
    pass # you may print some message or log something