CloudFlare Dynamic DNS (DDNS) for home server

cloudflare_ddns.md

CloudFlare Dynamic DNS (DDNS)

A CloudFlare Dynamic DNS (DDNS) cronjob for your home server!

Steps will be added soon!

cron_cloudflare_ddns.php

<?php

/**
 * Class CloudFlareAPI
 *
 * @author Jean-Pierre Fourie (emotality)
 * @link https://github.com/emotality
 * @link https://gist.github.com/emotality/bc5f699b553e51acbcebf25a14bcf2fd
 */
class CloudFlareAPI
{
    /**
     * The cURL handler.
     *
     * @var \CurlHandle $curl
     */
    private $curl;

    /**
     * If this script output needs to be logged to .log file.
     *
     * @var bool $save_to_log
     */
    private $save_to_log = true;

    /**
     * CloudFlare API base URL.
     *
     * @var string $cf_base_url
     */
    private $cf_base_url = 'https://api.cloudflare.com/client/v4';

    /**
     * CloudFlare API auth token (40 characters).
     *
     * @var string $cf_auth_token
     */
    private $cf_auth_token = 'XXXXXXXXXXXXX-XXXXXXXXXXXXXXXXXXXXXXXXXX';

    /**
     * The CF DNS domain (32 characters).
     *
     * @var string $cf_dns_zone
     */
    private $cf_dns_zone = 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';

    /**
     * The CF DNS record that should be updated (32 characters).
     *
     * @var string $cf_dns_record
     */
    private $cf_dns_record = 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';

    /**
     * The domain/DNS record parameters.
     *
     * @var string $record_params
     * @link https://api.cloudflare.com/#dns-records-for-a-zone-update-dns-record
     */
    private $record_params = [
        'type'    => 'A',
        'name'    => 'home.example.com', // The domain you are updating.
        'content' => null, // This will be filled with new IP address.
        'ttl'     => 1800, // Will be set to "Auto" if `proxied` is set to "true".
        'proxied' => true, // Do NOT set to "true" if you want to SSH or get the real IP.
    ];

    /**
     * CloudFlareAPI constructor.
     */
    public function __construct()
    {
        $url = sprintf('%s/zones/%s/dns_records/%s', $this->cf_base_url, $this->cf_dns_zone, $this->cf_dns_record);

        $this->curl = curl_init($url);

        curl_setopt($this->curl, CURLOPT_RETURNTRANSFER, true);
    }

    /**
     * Compare IP addresses then update to CloudFlare.
     *
     * @return bool
     */
    public function updateCloudFlareIP()
    {
        $my_ip = $this->getMyCurrentIP();
        $cf_ip = $this->getCloudFlareIP();

        if (! $my_ip || ! $cf_ip) {
            $this->echo('Could not get your current and/or CloudFlare IP address!', true, false);
            return false;
        }

        if ($my_ip == $cf_ip) {
            $this->echo('Your CloudFlare IP is already up to date!');
            return true;
        }

        return $this->setCloudFlareIP($my_ip);
    }

    /**
     * Get my current public IP address.
     *
     * @return string|null
     */
    private function getMyCurrentIP() : ?string
    {
        return trim(file_get_contents('http://ipecho.net/plain')) ?? null;
    }

    /**
     * Get the current IP on CloudFlare.
     *
     * @return string|null
     * @link https://api.cloudflare.com/#dns-records-for-a-zone-dns-record-details
     */
    private function getCloudFlareIP() : ?string
    {
        $header = [
            'Accept: application/json',
            sprintf('Authorization: Bearer %s', $this->cf_auth_token),
        ];

        curl_setopt($this->curl, CURLOPT_CUSTOMREQUEST, 'GET');
        curl_setopt($this->curl, CURLOPT_HTTPHEADER, $header);

        $response = curl_exec($this->curl);
        $error = curl_error($this->curl);

        if (! empty($error)) {
            $this->echo($error, true);
        } elseif ($json = json_decode($response)) {
            return $json->result->content ?? null;
        }

        return null;
    }

    /**
     * Set the new IP on CloudFlare.
     *
     * @param  string  $new_ip
     * @return bool
     * @link https://api.cloudflare.com/#dns-records-for-a-zone-update-dns-record
     */
    private function setCloudFlareIP(string $new_ip) : bool
    {
        $header = [
            'Content-Type: application/json',
            'Accept: application/json',
            sprintf('Authorization: Bearer %s', $this->cf_auth_token),
        ];

        // Set the new IP in the record parameters.
        $this->record_params['content'] = $new_ip;

        curl_setopt($this->curl, CURLOPT_CUSTOMREQUEST, 'PUT');
        curl_setopt($this->curl, CURLOPT_HTTPHEADER, $header);
        curl_setopt($this->curl, CURLOPT_POSTFIELDS, json_encode($this->record_params));

        $response = curl_exec($this->curl);
        $error = curl_error($this->curl);

        if (! empty($error)) {
            $this->echo($error, true);
        } elseif ($json = json_decode($response)) {
            $success = $json->success ?? false;
            $message = $success ? 'DNS updated successfully!' : 'DNS update failed!';
            $this->echo($message, ! $success);
            return $success;
        }

        return false;
    }

    /**
     * Echo out and append to log file.
     *
     * @param  string  $message
     * @param  bool  $error
     * @param  false  $exit
     * @return void
     */
    private function echo(string $message, bool $error = false, $exit = true)
    {
        echo $message = sprintf("[%s] %s\n", date('Y-m-d H:i:s'), $message);

        if ($this->save_to_log) {
            $log = sprintf('%s/%s.log', __DIR__, basename(__FILE__, '.php'));
            file_put_contents($log, $message, FILE_APPEND);
        }

        if ($exit) {
            exit($error ? 1 : 0);
        }
    }

    /**
     * CloudFlareAPI destructor.
     */
    public function __destruct()
    {
        curl_close($this->curl);
    }
}

(new CloudFlareAPI())->updateCloudFlareIP();