#!/usr/bin/python3
# Put this script into a Crontab on your Mailcow instance.
# I use an interval of 5 minutes.
import requests
import socket
# Your Mailcow API key
API_KEY=''
# The forwarding host you would like to whitelist
DYN_FWDHOST='dsl-dynamic-host.example.org'
# The public-facing hostname of your Mailcow instance
MAILCOW_HOSTNAME='mx.example.org'

s = requests.Session()
s.headers.update({'X-API-Key': API_KEY})
r = s.get('https://{}/api/v1/get/fwdhost/all'.format(MAILCOW_HOSTNAME))
r.raise_for_status()
current_fwdhosts = r.json()
print('got current hosts: {}'.format(r.text))
home_ip = socket.gethostbyname(DYN_FWDHOST)
current_ips = [x['host'] for x in current_fwdhosts]
if home_ip in current_ips:
    exit('Home IP already registered, exiting.')
fwdhosts_to_delete = []
if current_fwdhosts:
    for host in current_fwdhosts:
        if host['source'] == DYN_FWDHOST:
            fwdhosts_to_delete.append(host['host']) # ['host'] => IP
d = s.post('https://{}/api/v1/delete/fwdhost'.format(MAILCOW_HOSTNAME), json=fwdhosts_to_delete)
print('Deleted hosts {} with response {}:'.format(str(fwdhosts_to_delete), d.status_code))
print(d.text)
a = s.post('https://{}/api/v1/add/fwdhost'.format(MAILCOW_HOSTNAME), json={
    'filter_spam':'0',
    'hostname': DYN_FWDHOST
    })
print('Added host {} with response {}'.format(DYN_FWDHOST, a.status_code))
exit(0)