monitor network status using systemconfigure

network.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

from Foundation import *
from SystemConfiguration import *

import os
import commands


EVENT_LIST=['State:/Network/Global/IPv4']



def getIpAddress(iname):
    status,output = commands.getstatusoutput("ifconfig | grep -A4 %s | grep 'inet\>' | awk '{print $2}'" % iname)
    if status != 0 :
        print "error while get ip address"
        import sys
        sys.exit(-1)
    return output

def onIpChange(store, keys, info):
    if SCDynamicStoreCopyValue(store, keys[0]) is not  None:
        print getIpAddress('en1')
            

store = SCDynamicStoreCreate(None, "ip change watcher", onIpChange, None)
SCDynamicStoreSetNotificationKeys(store, None, EVENT_LIST)
CFRunLoopAddSource(CFRunLoopGetCurrent(), SCDynamicStoreCreateRunLoopSource(None, store, 0), kCFRunLoopCommonModes)

CFRunLoopRun()