#! /usr/bin/env python

# This script notifies me when my IP address has changed. Intended to be run by
# a cron job frequently.

# This software is distributed according to the terms of the Gnu General
# Public License. See http://www.gnu.org for more information. This software
# comes with no warranty whatsoever, implied or otherwise.

import os, re, smtplib

IPFILE = '/home/user/data/ip'
FROMADDR = 'ipcheck@localhost.localdomain'
TOADDR = 'user@domain.com'
SUBJECT = 'new IP address'

#------------------------------------------------------------------------------#
def main():
    currIP = getCurrIP()
    storedIP = getStoredIP()

    if currIP != storedIP:
        setStoredIP(currIP)
        sendNewIP(currIP)
#------------------------------------------------------------------------------#
def getCurrIP():
    ifconf = os.popen('/sbin/ifconfig').readlines()
    p = re.compile('^.*inet addr:((\d{1,3}\.?){4})')
    return p.match(ifconf[1]).group(1)
#------------------------------------------------------------------------------#
def getStoredIP():
    ipFile = open(IPFILE)
    storedIP = ipFile.readline()
    ipFile.close()
    storedIP = storedIP[0:-1]  # kill the \n
    return storedIP
#------------------------------------------------------------------------------#
def setStoredIP(ip):
    ipFile = open(IPFILE, 'w')
    ipFile.write(ip + "\n")
    ipFile.close()
#------------------------------------------------------------------------------#
def sendNewIP(ip):
    msg = ("From: %s\r\nTo: %s\r\nSubject: %s\r\n\r\n"
        % (FROMADDR, TOADDR, SUBJECT))
    msg = msg + "oobleck's new ip is " + ip
    svr = smtplib.SMTP(ip)  # connecting to smtp on local host
    svr.sendmail(FROMADDR, TOADDR, msg)
    svr.quit()
#------------------------------------------------------------------------------#
main()