How to know if connection is active when using telnetlib?

[Wojciech Halicki-Piszko]

How to know if connection is active after telnetlib.Telne t.open(host,por t)?

[Eddie Corns]

Wojciech Halicki-Piszko <wh*@wp.pl> writes:

How to know if connection is active after telnetlib.Telne t.open(host,por t)?

If open() doesn't throw an exception then you should have a connection you can
start reading/writing with. Unless you have some special meaning for
'active'?

I'm just basing this on reading telnetlib.py.

Eddie

[sp1d3rx]

Well, running this code:
----------

import telnetlib
c = telnetlib.Telne t("blah")

----------
throws this exception:
----------
socket.gaierror : (11001, 'getaddrinfo failed')
----------
note that this is the same as your "telnetlib.Teln et.open". So, you
will want to use TRY: and EXCEPT: to catch those errors, as in the
example code below...
----------
import telnetlib
try:
c = telnetlib.Telne t("blah")
except socket.gaierror :
print "host could not be found."
----------
Note that the "socket.gaierro r" is thrown when the hostname is invalid,
and "socket.err or" is thrown when the connection is refused. If you try
to perform a "read" operation on a closed socket, you'll get thrown a
"EOFerror" or you may get a Null value. You'll have to handle each
case. I would suggest referring to the documentation at
"http://www.python.org/doc/2.4/lib/telnet-objects.html" for more
information about errors / exceptions returned. If there is none
specified, chances are, it will throw a "socket.*" exception, or a Null
value.

[Wojciech Halicki-Piszko]

> If open() doesn't throw an exception then you should have a connection you can

start reading/writing with. Unless you have some special meaning for
'active'?

I'm just basing this on reading telnetlib.py.

Eddie

Well, in fact what I meant is: I won't to check wether established
connection is still active. I have a reading thread and when I send 'quit'
command to a server it (guess what:)) disconnects. So I get plenty of
unwanted output, I want to avoid this. So the problem is how can I inform
my reader thread it is not longer wanted when _server_ disconnects me? To
my defense: repetition is mother of science (in case you did answer and I
did not get it first time).