duckdns.py

'''
duckdns - update a https://duckdns.org domain

usage:
    duckdns host=hostname token=duckdns-token ip=[ip|local|net]

parameters:
    host  - name of host created at https://duckdns.org
    token - token of your account at https://duckdns.org
    ip    - ip (valid ip) 'local' (lan address) 'net' (internet address)

examples:
    dickdns host=foo token=bar ip=local
    dickdns host=foo token=bar ip=net
    dickdns host=foo token=bar ip=127.0.0.1
'''

import sys
import socket

try:
    from urllib import urlopen
except ImportError:
    from urllib.request import urlopen

def print_help():
    '''
    show help message and finish
    '''

    print(__doc__)
    sys.exit(1)

def parse_arguments():
    '''
    parse arguments formated as key=value and --key
    '''

    arguments = {}
    for param in sys.argv[1:]:
        if '=' in param:
            key, value = param.split('=')
            arguments[key] = value
        elif '--' in param:
            arguments[param.replace('--', '')] = True

    return arguments

def update_duckdns(domains, token, ipaddr):
    '''
    send request to https://duckdns.org
    '''

    url = "https://www.duckdns.org/update?domains={}&token={}&ip={}&verbose=true"
    response = urlopen(url.format(domains, token, ipaddr))
    return response.status, response.read()

def cmdline():
    '''
    parse command line parameters 
    '''

    arguments = parse_arguments()

    if 'host' not in arguments:
        print('host parameter is missing')
        print_help()

    if 'token' not in arguments:
        print('token parameter is missing')
        print_help()

    if 'ip' not in arguments:
        print('ip parameter is missing')
        print_help()

    if 'help' in arguments:
        print_help()

    if arguments['ip'] == 'local':
        arguments['ip'] = socket.gethostbyname(socket.gethostname())
    elif arguments['ip'] == 'net':
        arguments['ip'] = ''

    print(update_duckdns(arguments['host'], arguments['token'], arguments['ip']))

if __name__ == '__main__':
    cmdline()