Cloud Flare Automatic DNS Record Updater (PHP Script)

cloudflare-dns.php

#!/usr/bin/php
<?php
/**
 * Script used to update DNS records in Cloud Flare when server IP address changes.
 * My use case is to run this script on startup, when I spin up a new Digital Ocean VPS but
 * this could easily be used to update for dynamic DNS with a cronjob.
 *
 * Digital Ocean referral code: https://www.digitalocean.com/?refcode=3655e259ce29
 *
 * Requires PHP cURL
 * 
 * Copy to /usr/local/bin/
 * chmod +x /usr/local/bin/cloudflare-dns.php
 *
 * OR curl https://gist.githubusercontent.com/lewayotte/35424c0d34014e1ed1fa/raw/91740c4d678162ba95dcc8e6c9ed4aac75de54b0/cloudflare-dns.php > /usr/local/bin/cloudflare-dns.php && chmod +x /usr/local/bin/cloudflare-dns.php && vi /usr/local/bin/cloudflare-dns.php
 *
 * In Ubuntu, I added a simple sh script to /etc/network/if-up.d/cloudflare to the network has been setup.
 *    #!/bin/sh
 *    /usr/local/bin/cloudflare-dns.php > /dev/null
 *    exit 0
 *
 * But to do this as a cronjob, you could simply run `crontab -e` and something like this:
 *    * * * * * /usr/local/bin/cloudflare-dns.php > /dev/null
 *
 */

$token = 'API KEY from Cloud Flare'; //https://www.cloudflare.com/my-account
$email = 'Cloud Flare Account Email';
$domain = 'domain.tld';

$hostname = php_uname( 'n' ); //Gets current hostname
$new_ip = trim( `/sbin/ip addr show eth0 | grep "inet " | awk '{print $2}' | cut -f1  -d'/'` );  //Gets server's IP Address
$old_ip = trim( `host $hostname | grep 'has address' |  awk '{print $4}'` ); //Gets DNS's IP Address

if ( $new_ip !== $old_ip ) {// iIf the IP addresses are the same, we don't need to make any changes
	$api_url = 'https://www.cloudflare.com/api_json.html';
	$ch = curl_init();
	curl_setopt( $ch, CURLOPT_URL, $api_url );
	curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );

	$body = array(
		'a'	=> 'rec_load_all',
		'tkn'	=> $token,
		'email' => $email,
		'z' 	=> $domain,
	);
	curl_setopt( $ch, CURLOPT_POST, true );
	curl_setopt( $ch, CURLOPT_POSTFIELDS, $body );
	if ( $output = curl_exec( $ch ) ) {
		$results = json_decode( $output );
		if ( 'success' === $results->result ) {
			foreach( $results->response->recs->objs as $dns_entry ) {
				if ( $dns_entry->name === $hostname ) {
					$record_id = $dns_entry->rec_id;
					$new_entry = false;
					break;
				} else {
					$new_entry = true;
				}
			}
			if ( $new_entry ) {
				$body = array(
					'a' 	=> 'rec_new',
					'tkn'	=> $token,
					'email' => $email,
					'z'	=> $domain,
					'type'	=> 'A',
					'name' 	=> $hostname,
					'content' => $new_ip,
					'ttl' 	=> '1',
				);
				curl_setopt( $ch, CURLOPT_POSTFIELDS, $body );
                                if ( $output = curl_exec( $ch ) ) {
					$results = json_decode( $output );
			                if ( 'success' === $results->result ) {
						echo "IP Address added for hostname.\n";
					} else {
						printf( "Error adding ip address for hostname: %s\n", $results->msg );
					}
                                } else {
                                        echo "Error adding IP Address for hostname.\n";
                                }
			} else {
				$body = array(
					'a' 	=> 'rec_edit',
					'tkn' 	=> $token,
					'email' => $email,
					'z' 	=> $domain,
					'id' 	=> $record_id,
					'type' 	=> 'A',
					'name' 	=> $hostname,
					'content' => $new_ip,
					'ttl' 	=> '1',
				);
			        curl_setopt( $ch, CURLOPT_POSTFIELDS, $body );
				if ( $output = curl_exec( $ch ) ) {
					$results = json_decode( $output );
			                if ( 'success' === $results->result ) {
						echo "IP Address updated for hostname.\n";
					} else {
						printf( "Error adding ip address for hostname: %s\n", $results->msg );
					}
				} else {
					echo "Error changing IP Address for hostname.\n";
				}

			}
		} else {
			printf( "Error adding ip address for hostname: %s\n", $results->msg );
		}
	}

	curl_close( $ch );
} else {
	echo "No changes required\n";
}