Script to implement Cloudflare DDNS

cloudflare_ddns.py

#!/usr/bin/env python3

# The MIT License (MIT)
# Copyright (c) <2016> <brickgao>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.


import fcntl
import socket
import struct

import requests

CLOUDFLARE_EMAIL = ""
CLOUDFLARE_API_KEY = ""
CLOUDFLARE_ZONE_NAME = ""
CLOUDFLARE_DNS_RECORD_NAME = ""
CLOUDFLARE_BASE_API_URL = "https://api.cloudflare.com/client/v4"

BASE_HEADERS = {
    "X-Auth-Email": CLOUDFLARE_EMAIL,
    "X-Auth-Key": CLOUDFLARE_API_KEY,
    "Content-Type": "application/json"
}


class CloudFlareException(Exception):
    pass


def get_ip_address(ifname):
    _socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    return socket.inet_ntoa(
        fcntl.ioctl(
            _socket.fileno(),
            0x8915,
            struct.pack('256s', ifname[:15].encode("ascii"))
        )[20:24]
    )


def get_zone_id():
    request_url = "{0}/zones".format(CLOUDFLARE_BASE_API_URL)
    payload = {
        "name": CLOUDFLARE_ZONE_NAME
    }
    result = requests.get(
        request_url, params=payload, headers=BASE_HEADERS
    ).json()
    if result["success"]:
        return result["result"][0]["id"]
    else:
        raise CloudFlareException("Failed to get zone_id",
                                  result["error_chain"])


def get_dns_record_id(zone_id):
    request_url = "{0}/zones/{1}/dns_records".format(
        CLOUDFLARE_BASE_API_URL, zone_id
    )
    payload = {
        "name": CLOUDFLARE_DNS_RECORD_NAME
    }
    result = requests.get(
        request_url, params=payload, headers=BASE_HEADERS
    ).json()
    if result["success"]:
        return result["result"][0]["id"]
    else:
        raise CloudFlareException("Failed to get dns_record_id",
                                  result["error_chain"])


def update_dns_record(zone_id, dns_record_id, current_ip):
    request_url = "{0}/zones/{1}/dns_records/{2}".format(
        CLOUDFLARE_BASE_API_URL, zone_id, dns_record_id
    )
    payload = {
        "id": dns_record_id,
        "type": "A",
        "name": CLOUDFLARE_DNS_RECORD_NAME,
        "content": current_ip,
    }
    result = requests.put(
        request_url, json=payload, headers=BASE_HEADERS
    ).json()
    if not result["success"]:
        raise CloudFlareException("Failed to update DNS record",
                                  result["error_chain"])


def ddns():
    zone_id = get_zone_id()
    dns_record_id = get_dns_record_id(zone_id=zone_id)
    current_ip = get_ip_address("eth0")
    update_dns_record(zone_id=zone_id, dns_record_id=dns_record_id,
                      current_ip=current_ip)


if __name__ == "__main__":
    ddns()