[SOLVED] Python Telent not returning data

MrLinuxDonnelly · 11-03-2016, 09:39 AM

Hi All,

So i have a python script in which i wish to telnet locally to a port and print the data to start with.

Im opening the port however the print doesnt seem to work and i can see im buffering the input

Code:

import sys
import telnetlib

tn = telnetlib.Telnet("127.0.0.1",17051)
data = tn.read_all()
print "Data: " + data

Any idea why its not processing the data and then printing ?

szboardstretcher · 11-03-2016, 10:30 AM

Code:

import sys
import telnetlib
tn=telnetlib.Telnet("towel.blinkenlights.nl",23)
data=tn.read_until("Simon")
print "Data: " + data

The difference between read_all and read_until:

Telnet.read_until(expected[, timeout])
Read until a given string, expected, is encountered or until timeout seconds have passed.
When no match is found, return whatever is available instead, possibly the empty string. Raise EOFError if the connection is closed and no cooked data is available.

Telnet.read_all()
Read all data until EOF; block until connection closed.

MrLinuxDonnelly · 11-04-2016, 03:17 AM

Quote:

Originally Posted by szboardstretcher

Code:

import sys
import telnetlib
tn=telnetlib.Telnet("towel.blinkenlights.nl",23)
data=tn.read_until("Simon")
print "Data: " + data

The difference between read_all and read_until:

Telnet.read_until(expected[, timeout])
Read until a given string, expected, is encountered or until timeout seconds have passed.
When no match is found, return whatever is available instead, possibly the empty string. Raise EOFError if the connection is closed and no cooked data is available.

Telnet.read_all()
Read all data until EOF; block until connection closed.

Hey,

I want it to read whatever is being sent so thought the read_all would be best.

i tried the read_until as a test however didnt work.

$ python telnetTest2.py
Traceback (most recent call last):
File "telnetTest2.py", line 9, in ?
data = tn.read_until("Simon")
File "/usr/lib64/python2.4/telnetlib.py", line 317, in read_until
self.process_rawq()
File "/usr/lib64/python2.4/telnetlib.py", line 488, in process_rawq
self.cookedq = self.cookedq + buf[0]
KeyboardInterrupt

^^^^ i killed once it didnt output.

If i do a debug level i see what it should be doing

Telnet(127.0.0.1,17051): recv '\x01|\x00\x00\x00\x10Pp\x11\xc2\x8b\x91\x01\x96\x00\x00\x01\x01\x01\x00\x01|\x01\xf5\x00\x10Pp\x1b\ x86s\x8d\x00j\x00\x07\x002\x00\x8c\x00\x10\x06\x92\x00z\xfe\xbc\x01\xc6'

safe to say im pretty confused lol

szboardstretcher · 11-04-2016, 08:07 AM

Code:

tn=telnetlib.Telnet("towel.blinkenlights.nl",23)

This line is telling python to telnet to the site towel.blinkenlights.nl port 23 as a test. It shows a telnet version of star wars written by some guys, one of whom is named 'Simon'

Code:

data=tn.read_until("Simon")

This line says put all data from telnet stream into 'data' variable up to the word 'Simon'

If you ran the program on your telnet destination - and you do not have the word 'Simon' in the output - then it would never stop reading. So take my EXAMPLE and modify it to work for your setup.

MrLinuxDonnelly · 11-04-2016, 08:18 AM

Quote:

Originally Posted by szboardstretcher

Code:

tn=telnetlib.Telnet("towel.blinkenlights.nl",23)

This line is telling python to telnet to the site towel.blinkenlights.nl port 23 as a test. It shows a telnet version of star wars written by some guys, one of whom is named 'Simon'

Code:

data=tn.read_until("Simon")

This line says put all data from telnet stream into 'data' variable up to the word 'Simon'

If you ran the program on your telnet destination - and you do not have the word 'Simon' in the output - then it would never stop reading. So take my EXAMPLE and modify it to work for your setup.

Ahhh yes perfect i have it outputting what i want when i use the read_until

only problem i have is from what i understand read_all will read the output regardless, however if i change it to read all i dont output anything

szboardstretcher · 11-04-2016, 02:38 PM

Again:

Telnet.read_all()
Read all data until EOF; block until connection closed.

"read_all" will continue reading FOREVER until either an EOF(end of file marker) comes through telnet or the telnet connection closes. Your telnet connection doesn't appear to do either, staying open forever, so "read_all" will continue reading FOREVER without ever going to the next line "print data."

MrLinuxDonnelly · 11-07-2016, 04:41 AM

Quote:

Originally Posted by szboardstretcher

Again:

Telnet.read_all()
Read all data until EOF; block until connection closed.

"read_all" will continue reading FOREVER until either an EOF(end of file marker) comes through telnet or the telnet connection closes. Your telnet connection doesn't appear to do either, staying open forever, so "read_all" will continue reading FOREVER without ever going to the next line "print data."

Sorry read it wrong, was having a friday moment.

Thanks so much for your help