Help with regex on telnet output

[Adam Flott]

I'm having some difficulty getting the expect function of telnetlib to
capture some data that gets returned from a telnet connection.

Python's telnet debug reports this:

recv 'whoami\n\r\xff\xfc\x01\r\nHi, my name is : Home\r\nHere'
IAC WONT 1
recv ' is what I know about myself:\r\nModel: '
recv ' VSX 7000\r\nSerial Number: 822232085C63K\r\nS'
recv 'oftware Version: Release 1.0 - August 2001\r'
recv '\nBuild Information: build at www.'
recv 'a.com\r\nFPGA Revision: 4.3.0\r\nMain Proc'
recv 'essor: BSP15 v0.0 ~ Core/Mem Clks 415/111 '
recv '[3:4 0:3]\r\nTime In Last Call: 0:00:00\r\nTotal Tim'
recv 'e In Calls: 0:22:17\r\nTotal Calls: 18\r\nSNTP'
recv ' Time Service: auto insync 21.1.1.1\r\nLocal Tim'
recv 'e is: Mon, 5 Jul 2004 20:59:35 -0500\r\nNetw'
recv 'ork Interface: ISDN_QUAD_BRI\r\nIP Video Number: '
recv ' 192.168.0.99\r\nISDN Video Number: 1.555.115047'
recv '4\r\nH323 Enabled: True\r\nFTP Enabled: '
recv ' True\r\nHTTP Enabled: True\r\nSNMP Enabled: '
recv ' True\r\nNIC Slot 1 SW Ver: 6.03\r\nNIC Slot 1 B'
recv 'oot Ver: 0.02\r\n\xff\xfb\x03'
IAC WILL 3
recv '\xff\xfc\x01'
IAC WONT 1
recv '\xff\xfb\x03'
IAC WILL 3

The call I made to expect including a timeout of 1 seconds, which is
plenty of time to wait for a response, but keeps repeating WILL 3/WONT 1
indefinitely.

I only want to match from the begginning (\r\nHi. to the end 0.02\r\n).
This data is not specific and I just want data that looks like this
format to be returned from the call to expect. The only thing I've found
that is constant is a colon separates one side to the other.

Here is the start to the regular expression I've been trying to get to
work:

"^([\w\s]+?))\s{1,}(.*):?\r\n$"

I'm using Python version: Python 2.3.4 (#2, Jun 19 2004, 18:15:30) on
Debian unstable

Any help or direction is appreciated.


Adam

 

[Eddie Corns]

I'm having some difficulty getting the expect function of telnetlib to
capture some data that gets returned from a telnet connection.

Python's telnet debug reports this:

recv 'whoami\n\r\xff\xfc\x01\r\nHi, my name is : Home\r\nHere'
IAC WONT 1
recv ' is what I know about myself:\r\nModel: '
recv ' VSX 7000\r\nSerial Number: 822232085C63K\r\nS'
recv 'oftware Version: Release 1.0 - August 2001\r'
recv '\nBuild Information: build at www.'
recv 'a.com\r\nFPGA Revision: 4.3.0\r\nMain Proc'
recv 'essor: BSP15 v0.0 ~ Core/Mem Clks 415/111 '
recv '[3:4 0:3]\r\nTime In Last Call: 0:00:00\r\nTotal Tim'
recv 'e In Calls: 0:22:17\r\nTotal Calls: 18\r\nSNTP'
recv ' Time Service: auto insync 21.1.1.1\r\nLocal Tim'
recv 'e is: Mon, 5 Jul 2004 20:59:35 -0500\r\nNetw'
recv 'ork Interface: ISDN_QUAD_BRI\r\nIP Video Number: '
recv ' 192.168.0.99\r\nISDN Video Number: 1.555.115047'
recv '4\r\nH323 Enabled: True\r\nFTP Enabled: '
recv ' True\r\nHTTP Enabled: True\r\nSNMP Enabled: '
recv ' True\r\nNIC Slot 1 SW Ver: 6.03\r\nNIC Slot 1 B'
recv 'oot Ver: 0.02\r\n\xff\xfb\x03'
IAC WILL 3
recv '\xff\xfc\x01'
IAC WONT 1
recv '\xff\xfb\x03'
IAC WILL 3

The call I made to expect including a timeout of 1 seconds, which is
plenty of time to wait for a response, but keeps repeating WILL 3/WONT 1
indefinitely.

I only want to match from the begginning (\r\nHi. to the end 0.02\r\n).
This data is not specific and I just want data that looks like this
format to be returned from the call to expect. The only thing I've found
that is constant is a colon separates one side to the other.

Here is the start to the regular expression I've been trying to get to
work:

"^([\w\s]+?))\s{1,}(.*):?\r\n$"

The first thing to note is that expect does not MATCH in quite the same sense
as when matching a string. What it does is match all the input from where it
last left off until the point in the stream when the regex matches. eg:

if the stream looks like:

"$ whereami\nYou are here.\n$ "

and you match on "a.e", it will return "$ whereami\nYou are". The next read()
or expect() call will start from "here.\n$ "

You would need to either pull out the portion you want from within that or
more usually make sure you've matched up to the start. Secondly the ^ and $
don't really make sense on a stream ($ will certainly cause it to hang; not
sure why timeout doesn't fix that).

I generally try to use read_until() instead of expect(), this only works if
you have well defined strings you can match on eg. "Hi, my name is" to get the
start or better still match on the echo of the command you sent, and the user
level prompt to finish (there doesn't seem to be a prompt in your trace
though). At worst you can use timeouts to know when it's done.

Fixed strings leads to more robust applications and easier to read code IMHO.

Eddie

 

[Adam Flott]

I'm having some difficulty getting the expect function of telnetlib
to capture some data that gets returned from a telnet connection.

Python's telnet debug reports this:

recv 'whoami\n\r\xff\xfc\x01\r\nHi, my name is : Home\r\nHere'
IAC WONT 1
recv ' is what I know about myself:\r\nModel: '
recv ' VSX 7000\r\nSerial Number: 822232085C63K\r\nS'
recv 'oftware Version: Release 1.0 - August 2001\r'
recv '\nBuild Information: build at www.'
recv 'a.com\r\nFPGA Revision: 4.3.0\r\nMain Proc'
recv 'essor: BSP15 v0.0 ~ Core/Mem Clks 415/111 '
recv '[3:4 0:3]\r\nTime In Last Call: 0:00:00\r\nTotal Tim'
recv 'e In Calls: 0:22:17\r\nTotal Calls: 18\r\nSNTP'
recv ' Time Service: auto insync 21.1.1.1\r\nLocal Tim'
recv 'e is: Mon, 5 Jul 2004 20:59:35 -0500\r\nNetw'
recv 'ork Interface: ISDN_QUAD_BRI\r\nIP Video Number: '
recv ' 192.168.0.99\r\nISDN Video Number: 1.555.115047'
recv '4\r\nH323 Enabled: True\r\nFTP Enabled: '
recv ' True\r\nHTTP Enabled: True\r\nSNMP Enabled: '
recv ' True\r\nNIC Slot 1 SW Ver: 6.03\r\nNIC Slot 1 B'
recv 'oot Ver: 0.02\r\n\xff\xfb\x03'
IAC WILL 3
recv '\xff\xfc\x01'
IAC WONT 1
recv '\xff\xfb\x03'
IAC WILL 3

The call I made to expect including a timeout of 1 seconds, which is
plenty of time to wait for a response, but keeps repeating WILL
3/WONT 1 indefinitely.

I only want to match from the begginning (\r\nHi. to the end
0.02\r\n). This data is not specific and I just want data that looks
like this format to be returned from the call to expect. The only
thing I've found that is constant is a colon separates one side to
the other.

Here is the start to the regular expression I've been trying to get
to work:

"^([\w\s]+?))\s{1,}(.*):?\r\n$"

The first thing to note is that expect does not MATCH in quite the
same sense as when matching a string. What it does is match all the
input from where it last left off until the point in the stream when
the regex matches. eg:

if the stream looks like:

"$ whereami\nYou are here.\n$ "

and you match on "a.e", it will return "$ whereami\nYou are". The
next read() or expect() call will start from "here.\n$ "

You would need to either pull out the portion you want from within
that or more usually make sure you've matched up to the start.
Secondly the ^ and $ don't really make sense on a stream ($ will
certainly cause it to hang; not sure why timeout doesn't fix that).

I generally try to use read_until() instead of expect(), this only
works if you have well defined strings you can match on eg. "Hi, my
name is" to get the start or better still match on the echo of the
command you sent, and the user level prompt to finish (there doesn't
seem to be a prompt in your trace though). At worst you can use
timeouts to know when it's done.

Fixed strings leads to more robust applications and easier to read
code IMHO.

Eddie[/QUOTE]


After I read your message I finnally figured out a solution. Just match
the Hi part with the 6 or so variants that I know I will recieve. There
isn't a prompt as this is an embedded device and doesn't work like a
normal telnet login. The timeout issue is still a problem and I will
have to investigate that further. But for another day.

Thanks for the help, it is greatly appreciated.


Adam

 

[Eddie Corns]

After I read your message I finnally figured out a solution. Just match
the Hi part with the 6 or so variants that I know I will recieve. There
isn't a prompt as this is an embedded device and doesn't work like a
normal telnet login. The timeout issue is still a problem and I will
have to investigate that further. But for another day.

OK, I'll just re-emphasise one point. A minimal bit of testing suggests that
^ and $ will always cause it to hang. My guess is that, although the timeout
code works on the connection, it will never ever have anything to match
against because these conditions cannot occur in a stream (there is no
equivalent to End-Of-String) so it will keep going back and looking and not
finding anything to match that $.

Eddie