E-mail notification of changes in global IP address

send-global-ip.py

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

import os
import urllib
import smtplib
from email.MIMEText import MIMEText
from email.Utils import formatdate
import datetime

def get_global_ip():
    url = "http://higebu.com/remote_addr.php"
    res = urllib.urlopen(url)
    ip =  res.readline()
    return ip

def create_message(from_addr, to_addr, subject, body):
    msg = MIMEText(body)
    msg['Subject'] = subject
    msg['From'] = from_addr
    msg['To'] = ','.join( to_addr )
    msg['Date'] = formatdate()
    return msg

def send_via_gmail(from_addr, to_addr, msg):
    s = smtplib.SMTP('smtp.gmail.com', 587)
    s.ehlo()
    s.starttls()
    s.ehlo()
    s.login('your-account@gmail.com', 'password')
    s.sendmail(from_addr, to_addr, msg.as_string())
    s.close()

def main():
    new_ip = get_global_ip()
    old_ip = ''
    if os.path.exists('ip.txt'):
        f = open('ip.txt', 'r')
        old_ip = f.readline()
    if new_ip != old_ip:
        from_addr = 'your-account@gmail.com'
        to_addr = ['to_addr1@example.com', 'to_addr2@example.com']
        subject = 'Global IP has been changed at ' + datetime.datetime..now().strftime(u'%Y/%m/%d %H:%M:%S')
        body = new_ip
        msg = create_message(from_addr, to_addr, subject, body)
        send_via_gmail(from_addr, to_addr, msg)
        f = open('ip.txt', 'w')
        f.write(new_ip)
    f.close()

if __name__ == '__main__':
    main()