[Twisted-Python] Telnet negotiation with Twisted

[Patrick Mylund Nielsen]

For clarity, self.linemode has no special significance--it was just an
easy way to keep track of what was negotiated with the client.

On Fri, Dec 2, 2011 at 01:26, Patrick Mylund Nielsen
<twisted at patrickmylund.com> wrote:
> Hi Lee,
>
> Does using TelnetTransport 'will' and 'requestNegotation' work? E.g.
>
> self.will(LINEMODE)
> self.requestNegotiation(LINEMODE, '')
>
> I'm not completely sure about LINEMODE, but if the client sends back a
> DO, you might use something like:
>
> class MyTransport(TelnetTransport):
>
>    def connectionMade(self):
>        self.linemode = False
>        self.will(LINEMODE)
>        TelnetTransport.connectionMade(self)
>
>    def commandReceived(self, command, argument):
>        if argument == LINEMODE:
>            if command == DO:
>                self.requestNegotiation(LINEMODE, '')
>                self.linemode = True
>            elif command == DONT:
>                pass
>        else:
>            TelnetTransport.commandReceived(self, command, argument)
>
>    def write(self, data):
>        if self.linemode:
>            # do something special
>        else:
>            self.transport.write(data)
>
> Best,
> Patrick
>
> On Fri, Dec 2, 2011 at 01:12, Lee Orsino <lmorsino at gmail.com> wrote:
>> Hi all,
>>
>> I'm writing a twisted Telnet server and I want a client to be able to
>> connect to it through some other interface, such as PuTTY.  I can make the
>> connection fine. But one of my requirements is to be able to tell the client
>> to switch back and forth between buffered and unbuffered input modes
>> depending on the state of the server. (Sometimes, the client should enter
>> text, then hit enter to send. Other times, the client should send data
>> character-by-character).
>>
>> I'm new at this, and maybe I'm missing something, but in my TelnetTransport
>> object, I do something like this to disable buffering of client data:
>>
>> self.transport.write(IAC + WILL + LINEMODE)
>> self.transport.write(IAC + SB + LINEMODE + MODE + chr(0) + IAC + SE)
>>
>> Not working though. PuTTY still requires me to hit <enter> after I type.
>> I've tried various combinations of the above. I'm sure I'm doing something
>> wrong but its just really hard to find an example of this on the net. I'd
>> appreciate some advice as to how to proceed, or a simple example if you have
>> time...
>>
>> I'm using the twisted Telnet classes found here:
>> http://twistedmatrix.com/trac/browser/tags/releases/twisted-8.2.0/twisted/conch/telnet.py
>>
>> Thanks!
>>
>>
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