python script to email me the dynamic ip from tp-link router

At home, my boxes are connected to internet by Beijing ADSL.
when connected, Beijing ADSL gives me a dynamic ip and it changes about every 24 hours.
Before I get the dynamic ip by a service provided by oray.net.
However recently the service is broken.
So I have to write a python script to check the dynamic ip from my tp-link router every 3 minutes and if it changed, emails the new dynamic ip to my gmail.

I also write a bash script to run the above python script at boot on my gentoo linux.

The python script:

#!/usr/bin/python

import urllib
import urllib2
import libgmail
import cookielib
import sys
import re
import base64
import socket
import time
from urlparse import urlparse

nowip=''
logfile=open('/var/log/ipsender.log','w')

def log(s):
  now=time.strftime('%Y-%m-%d %X')
  logfile.write('%s %sn'%(now,s))
  logfile.flush()

def gmailsender(to_addr,subject,msg):
  username='xxx@gmail.com'
  password='xxx'
  ga=libgmail.GmailAccount(username,password)
  ga.login()
  gmsg=libgmail.GmailComposedMessage(to_addr,subject,msg)
  ga.sendMessage(gmsg)

def check():
  global nowip
  timeout=10
  socket.setdefaulttimeout(timeout)
  username = 'admin'
  password = 'xxx'
  try:
    theurl='http://192.168.1.1/userRpm/StatusRpm.htm'
    req = urllib2.Request(theurl)
    base64string = base64.encodestring('%s:%s' % (username, password))[:-1]
    authheader =  "Basic %s" % base64string
    req.add_header("Authorization", authheader)
    handle = urllib2.urlopen(req)
    str=handle.read()
    ss='var wanPara = new Array'
    start=str.index(ss)+ss.__len__()
    end=str.index(';',start)
    s2=str[start:end]
    log(s2)
    t=eval(s2)
    log(t[2])
    handle.close()
    if nowip!=t[2]:
      nowip=t[2]
      gmailsender('mygmail@gmail.com','ddnsip===%s'%nowip,s2)
      log('send %s successfully.'%nowip)
    else:
      log('ddnsip remains %s.'%nowip)
  except:
    log('Unexpected error:', sys.exc_info()[0])

def main():
  while True:
    check()
    time.sleep(3*60)

main()

The bash script put in /etc/init.d/:

#!/sbin/runscript
# Copyright 1999-2004 Gentoo Foundation
start()	{
	ebegin "Starting ipsender"
	nohup python /home/zeaster/amp/ipsender.py >> /var/log/ipsender-nohup.log&
	eend $?
}
stop()	{
	ebegin "Stopping ipsender unsuccessfully"
	eend $?
}