Simple Cloudflare DDNS Client/Updater

Why am I publishing this?

Because I couldn't find anything simple to set up Cloudflare as a kind of DDNS without overkill, and I want others to have a good and simple-to-use resource for doing just that.

Note

I am not planning to actively maintain this for a while thanks to exam stress. I might start doing so in a few weeks, but for now, everything is working as intended. (This does not mean I won't try to fix reported bugs, but I likely won't add new features for now.)

Also, this is more of a "Works on my machine" thing, I can't guarantee it will work on yours too.

That being said, I hope it will work for you with less trouble than with other software!

Installation

1. Download the JAR from the Releases Tab
2. Get your Zone ID from Cloudflare. See here for more.
3. Get a token for the Cloudflare API. See here for more.
4. Write your configuration file. See Configuration for more.
5. Run the JAR: java -jar path/to/jar path/to/config.json

Once finished, you can also set the above command to run periodically using cron-jobs, Task Scheduler or any other tool.

Dependencies

Tool	Why does it need to be installed?	How to check for installation
curl	Curl needs to be installed in order to check the public IP address for both IPv4 and IPv6 because Java is not able to let the developer decide which one to use when.	curl --version
java	Java needs to be installed in order to run this tool.	java --version

Configuration

Overview

The config file is written in JSON and consists of the zoneId, apiToken and records tag.

The first two are Strings, and, of course, contain your Zone ID and API Token (Remove any spaces in the strings!).

The records tag is an Array of individual objects, each one containing an ipv tag and the recordId tag.

ipv can have the value 4 to update the record to your public IPv4 address, or 6 to update it with your public IPv6 address.

recordId is the ID of the DNS Record. You can get the ID of your DNS Records with the following command (requires jq):

curl "https://api.cloudflare.com/clients/v4/zones/<ZONE_ID>/dns_records" -H "Authorization: Bearer <API_TOKEN>" | jq .result

Example

Example Configuration

{
  "apiToken": "1234567890ABCDEF123456",
  "zoneId": "1234567890ABCDEF",

  "records": [
    {"ipv": "4", "recordId": "1234567890"},
    {"ipv": "4", "recordId": "1234567890"},
    {"ipv": "6", "recordId": "1234567890"},
    {"ipv": "6", "recordId": "1234567890"}
  ]
}