A simple script that gets your current public IP and then updates the no-ip service

update_no_ip.py

#!/usr/bin/env python
import argparse
import os.path
import requests
import sys
import ConfigParser
from datetime import datetime

IP_CACHE_FILE = "ipaddress.cache"
USER_AGENT = "no-ip Python Update Client/v1.0 igor.serko@gmail.com"


def print_out(msg):
    dt = datetime.now().strftime("%Y-%m-%dT%H:%M:%S")
    print dt, msg


def get_new_ip():
    headers = {'User-Agent': USER_AGENT}
    req = requests.get('http://jsonip.com')
    if int(req.status_code) != 200:
        raise Exception("Couldn't get new IP from jsonip. "
                        "Code=%s. Text=%s" % (req.status_code, req.text))
    response = req.json()
    return response["ip"]


def get_old_ip():
    if os.path.exists(IP_CACHE_FILE):
        with open(IP_CACHE_FILE, 'r') as fname:
            return fname.read().strip()
    return ""


def set_new_ip(new_ip):
    with open(IP_CACHE_FILE, 'w') as fname:
        fname.write(new_ip)


def update_ip(new_ip, config):
    headers = {'User-Agent': USER_AGENT}
    params = {'hostname': config['hostname'],
              'myip': new_ip}
    url = 'https://dynupdate.no-ip.com/nic/update'
    req = requests.get(url,
                       auth=(config['username'], config['password']),
                       params=params,
                       headers=headers)
    if int(req.status_code) != 200:
        raise Exception("no-ip returned an error. Status code=%s. "
                        "Text=%s" % (req.status_code, req.text))


def get_configuration(conf_file):
    config = ConfigParser.ConfigParser()
    config.read(conf_file)
    username = config.get('no-ip', 'username')
    password = config.get('no-ip', 'password')
    hostname = config.get('no-ip', 'hostname')
    return {'username': username,
            'password': password,
            'hostname': hostname}


def run():
    parser = argparse.ArgumentParser()
    parser.add_argument('-c', '--config',
                        default='no-ip.config',
                        help='no-ip config file')
    parser.add_argument('-v', '--verbose',
                        action='store_true')
    options = parser.parse_args()
    if not os.path.exists(options.config):
        parser.error('Config file %s does not exist' % options.config)
    config = get_configuration(options.config)
    old_ip = get_old_ip()
    if options.verbose:
        print_out("Got old IP: %s" % old_ip)
    new_ip = get_new_ip()
    if options.verbose:
        print_out("Got new IP: %s" % new_ip)
    if new_ip != old_ip:
        if options.verbose:
            print_out("Public IP changed from %s to %s" % (old_ip, new_ip))
        update_ip(new_ip, config)
        set_new_ip(new_ip)



if __name__ == '__main__':
    sys.exit(run())