Virtualmin Dynamic DNS (DDNS) server

ddns-api.php

<?php

// This script receives DDNS updates via HTTP
// example: http://server/ddns-api.php?name=home = updates home.domain.com to IP of requester

define('DDNS_DATA_FILE', '/home/ddns/ddns.json');
define('DDNS_DOMAIN', 'example.com');

header("Content-type: text/plain");

class ddns {
        public $name;
        public $ip;
}

function print_data($data) {
        foreach ($data as $dat) {
                echo "{$dat->name}.".DDNS_DOMAIN.":\t\t{$dat->ip}\n";
        }
}

$data = json_decode(file_get_contents(DDNS_DATA_FILE)) or new stdObject();

if (!isset($_GET['name'])) {
        echo "Not enough parameters. Available params:\n";
        echo " &name    name of subdomain\n";
        echo " &ip      the ip - can be left blank\n";
        echo " &action  the action of the command. default is update, can also be delete.\n";
        echo "\n";
        print_data($data);
        die();
}

if (isset($_GET['ip'])) {
        $ip = $_GET['ip'];
} else {
        $ip = $_SERVER['REMOTE_ADDR'];
}

if (!isset($_GET['action']) || ($_GET['action'] == 'update')) {
        $object = new ddns;
        $object->name = $_GET['name'];
        $object->ip = $ip;
        $data->{$object->name} = $object;
} elseif ($_GET['action'] == 'delete') {
        unset($data->{$_GET['name']});
}

file_put_contents(DDNS_DATA_FILE, json_encode($data));

print_data($data);

ddns-cron.php

#!/usr/bin/php
<?php

// This script should run as cronjob under root and parses the DDNS data

define('DDNS_DATA_FILE', '/home/ddns/ddns.json');
define('DDNS_DOMAIN', 'example.com');

$dns_entries = file_get_contents(DDNS_DATA_FILE);
$dns_entries = json_decode($dns_entries);

$domain = DDNS_DOMAIN;

$virtualmin_bin = "/usr/sbin/virtualmin";
$modify_dns_cmd = "modify-dns --domain $domain";
$command_remove = "$virtualmin_bin $modify_dns_cmd --remove-record";
$command_add = "$virtualmin_bin $modify_dns_cmd --add-record-with-ttl";

$output = "\n\n\n---------------------\n";
$output .= date('l jS \of F Y h:i:s A') . "\n\n";

foreach ($dns_entries as $entry) {
        // Remove old DNS thing.
        $command = "$command_remove \"{$entry->name} A\"";
        $output .= "-> " . $command . "\n";
        $output .= shell_exec($command) . "\n";
        // Add new DNS thing.
        $command = "$command_add \"{$entry->name} A 600 {$entry->ip}\"";
        $output .= "-> " . $command . "\n";
        $output .= shell_exec($command) . "\n";
}

file_put_contents("/var/log/ddns.log", $output, FILE_APPEND);