Twisted/wxPython Problem...

[PeterG]

Hi,

I am relatively new to Python, and am learning it as part of a
university
module...

Im currently undertaking a project to create an IM server and IM gui
client.

I have a very basic server, and a basic gui client. I can get my
client to
connect to my server, but cant get it to disconnect or send messages to
the
server.

I am getting the following error when I click on the 'Disconnect'
button -
AttributeError: 'NoneType' object has no attribute 'loseConnection'

I have attached the code for both the server and the client below this.

I am using the Twisted and wxPython packages, and as previously stated
am
fairly new to Python so would appreciate any help anyone can offer.

Thanks,

Peter

server.py
------------
from twisted.internet import reactor
from twisted.internet.protocol import Factory
from twisted.protocols.basic import LineReceiver

factory = Factory()
#this is a list
factory.transports = []
#this is a dictionary
userNicknames = {}

class SimpleLogger(LineReceiver):

def connectionMade(self):
self.factory.transports.append(self.transport)
userNicknames[self.transport.client] = ''
#write to the client
self.transport.write("Welcome to Chris & Pete's chat server!\r\n")
self.transport.write("Please enter your nickname:\r\n")
#prints on the server screen
print 'got connection from', self.transport.client

def connectionLost(self, reason):
who = str(userNicknames.get(self.transport.client)) + '
Disconnected' + '\r\n'
print who
userNicknames[self.transport.client] = ''
for transport in self.factory.transports:
transport.write(who)


def lineReceived(self, line):
#if the users nickname in the dictionary (userNicknames) is
blank, create a
#value in the dictionary with the line just received.
#if the user already has a nickname then it must be a message
they are writing.
#So instead print out the message
if userNicknames.get(self.transport.client) == '':
#if the username is already in the dictionary someone is
#already using it so ask for another one.
if line in userNicknames.values():
self.transport.write('That nickname is already in use,
please use another:')
else:
userNicknames[self.transport.client] = line
#print userNicknames.items()
message = userNicknames.get(self.transport.client) + '
has joined\r\n'
for transport in self.factory.transports:
transport.write(message)

else:
message = userNicknames.get(self.transport.client) + ': ' +
line + '\r\n'
for transport in self.factory.transports:
transport.write(message)

factory.protocol = SimpleLogger

reactor.listenTCP(1234, factory)
reactor.run()


client.py
----------
from wxPython.wx import *
import wx
from twisted.internet import wxreactor
wxreactor.install()
from twisted.internet import reactor
from twisted.internet.protocol import Protocol, ClientCreator

class imApp(wxApp, Protocol):

def buildMe(self):
frame = wx.Frame(None, title="IM Client", size=(800, 550))

bkg = wx.Panel(frame)

global ipAdd
global portNo
global messages
global newMsg

ipAddLab = wx.StaticText(bkg, -1, 'IP Address: ')
ipAdd = wx.TextCtrl(bkg)
ipAdd.SetToolTipString('Please enter the server IP address
here.')
spacer1 = wx.StaticText(bkg, -1, ' ')
portNoLab = wx.StaticText(bkg, -1, 'Port No: ')
portNo = wx.TextCtrl(bkg)
portNo.SetToolTipString('Please enter the port number the
server is using here.')
spacer2 = wx.StaticText(bkg, -1, ' ')
connectButton = wx.Button(bkg, label='Connect')
connectButton.SetToolTipString('Click this button to connect to
the server.')
connectButton.Bind(wx.EVT_BUTTON, self.connectMe)
disconnectButton = wx.Button(bkg, label='Disconnect')
disconnectButton.SetToolTipString('Click this button to
disconnect from the server.')
disconnectButton.Bind(wx.EVT_BUTTON, self.disconnectMe)
messages = wx.TextCtrl(bkg, style=(wx.TE_MULTILINE |
wx.HSCROLL))
newMsg = wx.TextCtrl(bkg)
sendButton = wx.Button(bkg, label='Send')
sendButton.SetToolTipString('Click this button to send a
message to the server.')
sendButton.Bind(wx.EVT_BUTTON, self.sendMe)

hbox1 = wx.BoxSizer()

hbox1.Add(ipAddLab, proportion=0, flag=wx.EXPAND)
hbox1.Add(ipAdd, proportion=0, flag=wx.EXPAND)
hbox1.Add(spacer1, proportion=0, flag=wx.EXPAND)
hbox1.Add(portNoLab, proportion=0, flag=wx.EXPAND)
hbox1.Add(portNo, proportion=0, flag=wx.EXPAND)
hbox1.Add(spacer2, proportion=0, flag=wx.EXPAND)
hbox1.Add(connectButton, proportion=0, flag=wx.LEFT, border=5)
hbox1.Add(disconnectButton, proportion=0, flag=wx.LEFT,
border=5)

hbox2 = wx.BoxSizer()
hbox2.Add(newMsg, proportion=1, flag=wx.EXPAND | wx.LEFT |
wx.LEFT | wx.LEFT, border=5)
hbox2.Add(sendButton, proportion=0, flag=wx.LEFT, border=5)

vbox = wx.BoxSizer(wx.VERTICAL)
vbox.Add(hbox1, proportion=0, flag=wx.EXPAND | wx.ALL,
border=5)
vbox.Add(messages, proportion=1, flag=wx.EXPAND | wx.LEFT |
wx.LEFT | wx.LEFT, border=5)
vbox.Add(hbox2, proportion=1, flag=wx.EXPAND | wx.ALL,
border=5)

bkg.SetSizer(vbox)

ipAdd.WriteText('localhost')
portNo.WriteText('1234')
frame.Show(true)
return true

def sendMe(self, e):
msg = newMsg.GetValue() + '\n'
messages.WriteText(msg)
newMsg.SetValue('')

def disconnectMe(self, e):
messages.WriteText('Disconnecting from server...\n')
self.transport.loseConnection()

def connectMe(self, e):
messages.WriteText('Connecting to server...\n')
c = ClientCreator(reactor, imApp)
ip = str(ipAdd.GetValue())
port = int(portNo.GetValue())
c.connectTCP(ip, port)

def mainProg():
app = imApp(0)
app.buildMe()
reactor.registerWxApp(app)
reactor.run()

if __name__ == '__main__':
mainProg()

 

[Diez B. Roggisch]

Hi,

I am relatively new to Python, and am learning it as part of a
university
module...

Im currently undertaking a project to create an IM server and IM gui
client.

I have a very basic server, and a basic gui client. I can get my
client to
connect to my server, but cant get it to disconnect or send messages to
the
server.

I am getting the following error when I click on the 'Disconnect'
button -
AttributeError: 'NoneType' object has no attribute 'loseConnection'

It seems that your client inherits from two classes, but doesn't invoke
their respective constructors. That makes python only call the first
classes constructor, as this simple experiment shows:

class A(object):
def __init__(self):
print "I'm A"

class B(object):
def __init__(self):
print "I'm B"


class C(A,B):
pass



C()


-> I'm A


so - create a constructor, invoke both constructors of your super-classes
either explicitly or using super (make sure you understand super!)


Regards,

Diez