Simplest way to test a connection

[pplanel]

So, Im using this code:

`#!/usr/bin/env python

-- coding: utf-8 --

from rdpy.protocol.rdp import rdp from twisted.internet import reactor from rdpy.core.error import RDPSecurityNegoFail

class RDPFactory(rdp.ClientFactory):

def __init__(self, username, password):
    self.username = username
    self.password = password

def clientConnectionLost(self, connector, reason):
    print "Connection lost. Reason: %s" % reason.type
    reactor.stop()

def clientConnectionFailed(self, connector, reason):
    print "Connection Failed. Reason: %s" % reason.type
    reactor.stop()

def buildObserver(self, controller, addr):
    controller.setUsername(self.username)
    controller.setPassword(self.password)

    class MyObserver(rdp.RDPClientObserver):

        def onReady(self):
            """
            @summary: Call when stack is ready
            """
            print "Observer ready"

        def onClose(self):
            """
            @summary: Call when stack is close
            """
            print "Obsever closed"

    return MyObserver(controller)

` Is there a way to have a credentials callback? If the username and password is wrong, how can I show it to the user?

Thanks