Python未處理錯誤回溯（最近一次調用）：

Question

這是我的代碼，我在尋找答案，但沒有一個能解決我的問題。 我是Twisted的新手，仍然在學習。

在Windows命令提示符下運行telnet localhost 72后，為什么會出現此錯誤？

這是我的代碼：

from twisted.internet.protocol import Factory
from twisted.protocols.basic import LineReceiver
from twisted.internet import reactor


class chatprotocol(LineReceiver):
    def __init__(self, factory):
        self.factory = factory
        self.name = None
        self.state = "REGiSTER"

    def connectionMade(self):
        self.sendLine("What's your Name?")

    def connectionLost(self, reason):
        if self.name in self.factory.users:
            del self.factory.Users[self.name]
            self.broadcastMessage("%s has left channel." % (self.name,))

    def lineReceived(self, line):
        if self.state == "REGISTER":
            self.handle_REGISTER(line)
        else:
            self.handle_CHAT(line)

    def handle_REGISTER(self, name):
        if name in self.factory.users:
            self.sendLine("Name taken , please choose another")
            return
        self.sendline("welcome ,%s!" % (name,))
        self.broadcastMessage("%s has joined the channel." % (name,))
        self.name = name
        self.factory.users[name] = self
        self.state = "CHAT"

    def handle_CHAT(self, message):
        message = "<%s> %s" % (self.name, message)
        self.broadcastMessage(message)

    def broadcastMessage(self, message):
        for name, protocol in self.factory.users.iteritems():
            if protocol != self:
                protocol.sendLine(message)

class ChatFactory(Factory):
    def __init__(self):
        self.users = {}

    def buildProtocol(self, addr):
        return chatprotocol(self)


reactor.listenTCP(72, ChatFactory())
reactor.run()

錯誤消息：

Unhandled Error
Traceback (most recent call last):
  File "C:\Python27\lib\site-packages\twisted\python\log.py", line 84, in callWithContext
    return context.call({ILogContext: newCtx}, func, *args, **kw)
  File "C:\Python27\lib\site-packages\twisted\python\context.py", line 118, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "C:\Python27\lib\site-packages\twisted\python\context.py", line 81, in callWithContext
    return func(*args,**kw)
  File "C:\Python27\lib\site-packages\twisted\internet\selectreactor.py", line 149, in _doReadOrWrite
    why = getattr(selectable, method)()
--- <exception caught here> ---
  File "C:\Python27\lib\site-packages\twisted\internet\tcp.py", line 1066, in doRead
    protocol = self.factory.buildProtocol(self._buildAddr(addr))
  File "C:\Python27\lib\site-packages\twisted\internet\protocol.py", line 131, in buildProtocol
    p = self.protocol()
exceptions.TypeError: 'NoneType' object is not callable

Answer 1

@firman您確定要給我們提供引起問題的精確代碼嗎？ 上面的代碼（如果編寫正確）可能無法給出該錯誤。 該錯誤發生在Factory類的buildProtocol函數中，您在示例中對其進行了重載。 我已經編輯了您的問題，並更正了一些語法錯誤。 再試一次，看看是否可行。 如果沒有，請發布您的代碼，這會給您帶來錯誤。

您未在工廠對象中設置protocol變量而導致的錯誤，它仍然是None 。 例如，讓我們在工廠類中注釋掉buildProtocol函數，使其看起來像這樣：

class ChatFactory(Factory):
    def __init__(self):
        self.users = {}

#    def buildProtocol(self, addr):
#        return chatprotocol(self)

我收到您最初遇到的錯誤：

--- <exception caught here> ---
  File "/Projects/virtenv/local/lib/python2.7/site-packages/twisted/internet/tcp.py", line 1066, in doRead
    protocol = self.factory.buildProtocol(self._buildAddr(addr))
  File "/Projects/virtenv/local/lib/python2.7/site-packages/twisted/internet/protocol.py", line 131, in buildProtocol
    p = self.protocol()
exceptions.TypeError: 'NoneType' object is not callable

要解決此問題，您可以做2件事情之一。 您可以重載buildProtocol()以返回所需的協議對象（在原始示例中已完成此操作）。 或者，您可以將工廠對象設置為變量，然后設置protocol類變量。 因此，您的主要方法應如下所示：

factory = ChatFactory()
factory.protocol = chatprotocol
reactor.listenTCP(72, factory)