Question

I’ve been trying to validate an inputted string (sys argv[1] in this case). I need to create a script that goes through a log file and matches the entries for source and destination ip with any argument input with the script. The kinds of valid inputs are either

• an IP or partial ip
• “any”(string which means all ip addresses in a given column).

So far I have the following code. Whenever I run the script in bash along with an argument (e.g any random number or word/alphabets etc) I get errors. Please let me know how I can fix them. Really appreciate a way to validate input against the IP address reg ex and the word any.

#!/usr/bin/python

import sys,re

def ipcheck(ip):
    #raw patterns for "any" and "IP":
    ippattern = '([1-2]?[0-9]?[0-9]\.){1,3}([1-2]?[0-9]?[0-9])?'
    anypattern = any
    #Compiled patterns
    cippattern = re.compile(ippattern)
    canypattern = re.compile(any)
    #creating global variables for call outside function    
    global matchip
    global matchany
    #matching the compiled pattern 
    matchip = cippattern.match(ip)
    matchany = canypattern.match(ip)

new = sys.argv[1]
snew = str(new)
print type(snew)
ipcheck(new)

Also I tried to do it this way but it kept giving me errors, is it possible to pass 2 arguments to an if loop via the “OR |” operator? How would I do it this way?[/b]

#if (matchip | matchany) :  
    #print "the ip address is valid"
#else:
    #print "Invalid Destination IP"


Error
========================

user@bt:/home# ./ipregex.py a
<type 'str'>
Traceback (most recent call last):
File "./ipregex.py", line 21, in <module>
ipcheck(new)
File "./ipregex.py", line 15, in ipcheck
matchany = re.match(anypattern,ip)
File "/usr/lib/python2.5/re.py", line 137, in match
return _compile(pattern, flags).match(string)
File "/usr/lib/python2.5/re.py", line 237, in _compile
raise TypeError, "first argument must be string or compiled pattern"
TypeError: first argument must be string or compiled pattern

==========================================================

EDIT

I was trying to match the IP without compiling the regex. So I modified the script to do so. This resulted in the error:

Error

user@bt:/home# ./ipregex.py a
<type 'str'>
Traceback (most recent call last):
File "./ipregex.py", line 21, in <module>
ipcheck(new)
File "./ipregex.py", line 15, in ipcheck
matchany = anypattern.match(ip)
AttributeError: 'builtin_function_or_method' object has no attribute 'match'

==========================================================

EDIT#2

I was able to reproduce my error in a simpler code version. What the heck am i doing wrong??????

#!/usr/bin/python

import sys
import re

def ipcheck(ip):
    anypattern = any
    cpattern = re.compile(anypattern)
    global matchany
    matchany = cpattern.match(ip)
    if matchany:
            print "ip match: %s" % matchany.group()
new = sys.argv[1]
ipcheck(new)

ERROR

user@bt:/home# ./test.py any
Traceback (most recent call last):
File "./test.py", line 14, in <module>
ipcheck(new)
File "./test.py", line 8, in ipcheck
cpattern = re.compile(anypattern)
File "/usr/lib/python2.5/re.py", line 188, in compile
return _compile(pattern, flags)
File "/usr/lib/python2.5/re.py", line 237, in _compile
raise TypeError, "first argument must be string or compiled pattern"
TypeError: first argument must be string or compiled pattern

Answer 1

When you use re.compile you call the match function on the compiled object: ippattern.match(ip). Also, to get to matched ip from a MatchObject, use MatchObject.group(). Fixed up your example some and it should now do what you need:

#!/usr/bin/python

import sys
import re

def ipcheck(ip):
    ippattern_str = '(([1-2]?[\d]{0,2}\.){1,3}([1-2]?[\d]{0,2})|any)'

    ippattern = re.compile(ippattern_str)
    # ippattern is now used to call match, passing only the ip string
    matchip = ippattern.match(ip)
    if matchip:
        print "ip match: %s" % matchip.group()

if len(sys.argv) > 1:
    ipcheck(sys.argv[1])

Some results:

[ 19:46 jon@hozbox ~/SO/python ]$ ./new.py 100.
ip match: 100.
[ 19:46 jon@hozbox ~/SO/python ]$ ./new.py 100.1.
ip match: 100.1.
[ 19:46 jon@hozbox ~/SO/python ]$ ./new.py 100.1.55.
ip match: 100.1.55.
[ 19:46 jon@hozbox ~/SO/python ]$ ./new.py 100.1.55.255
ip match: 100.1.55.255
[ 19:47 jon@hozbox ~/SO/python ]$ ./new.py any
ip match: any
[ 19:47 jon@hozbox ~/SO/python ]$ ./new.py foo
[ 19:47 jon@hozbox ~/SO/python ]$