Question

我试图在扭曲中执行一个简单的回调序列。我的想法是登录服务，登录成功后，我开始发送命令。这是我的代码：

from   twisted.internet          import reactor, defer

class MyService:

    def __init__ (self):
        self.handle = None

    def login(self):
        def onConnect(handle):
            self.handle = handle
            return
        df = defer.Deferred().addCallback(onConnect)
        reactor.callLater(2, df.callback, "dummyhandle")
        return df

    def sendCommand(self, command):
        def onResult(result):
            print result
            return result

        if self.handle == None:
            print "Not logged in"
            return
        else:
            df = defer.Deferred().addCallback(onResult, result ="xxx")
        return df

my = MyService ()

my.login().addCallback(my.sendCommand, command = "format")
reactor.run()

运行该代码会产生以下堆栈跟踪：

Unhandled error in Deferred: Traceback (most recent call last):   File "/usr/lib/python2.6/dist-packages/twisted/internet/base.py", line 1179, in mainLoop
    self.runUntilCurrent()   File "/usr/lib/python2.6/dist-packages/twisted/internet/base.py", line 778, in runUntilCurrent
    call.func(*call.args, **call.kw)   File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 280, in callback
    self._startRunCallbacks(result)   File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 354, in _startRunCallbacks
    self._runCallbacks()
--- <exception caught here> ---   File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 371, in _runCallbacks
    self.result = callback(self.result, *args, **kw) exceptions.TypeError: sendCommand() got multiple values for keyword argument 'command'

重要的是sendCommand不需要登录的结果，而是需要不同的数据。它需要登录已经完成（这就是我想要它在回调链中的原因），但它对登录结果不感兴趣（只要它不是错误，无论如何都会在错误链中处理）

我在这里做错了什么？

Answer 1

很简单，处理程序必须将结果作为其第一个参数：

def sendCommand(self, in_result, command):
    do_the_stuff

具有独立数据的回调链，与链无关

1 个答案: