PHP script to automatically update NO-IP hostname WAN IP address

myip.php

<?php
/**
 * Script that returns client IP address back to the client.
 */

// this password should be used in original script that calls this one via HTTP request.
$configPassword = 'PASSWORD_TO_USE_THIS_SCRIPT';

// check credentials
if (empty($_POST['passwd']) || $_POST['passwd'] != $configPassword) {
    header('Status: 403 Forbidden');
    exit('Access Denied');
}

$ip = empty($_SERVER['REMOTE_ADDR']) ? 'error' : $_SERVER['REMOTE_ADDR'];
die($ip);

updateip.php

#!/usr/bin/env php
<?php
/*
 * Simple script to update your NO-IP hostname IP address.
 * Change the following configuration values.
 */

// URI to script that will return your WAN IP. Create your own or use existing one from the same gist.
$ipDetectUrl = 'http://examplehost.com/myip.php';

// Your no-ip hostname you want to update
$configIpHost = 'YOUR_NO_IP_HOSTNAME';

// enter password for your ip check script or use ENV variable here
$configIpPassword = 'YOUR_IP_SCRIPT_PASSWORD';

// enter NO-IP API username for you no-ip service or use ENV variable here
$configNoIpUsername = 'YOUR_NO_IP_USERNAME';

// enter NO-IP API password for you no-ip service or use ENV variable here
$configNoIpPassword = 'YOUR_NO_IP_PASSWORD';

// always display errors so we can log them or mail them from cronjob
ini_set('display_errors', true);

/*
 * Get your WAN IP by making a request to IP check script.
 *
 * NOTE: You may change the following call to obtain new WAN IP address by calling some other service
 * instead of making a HTTP request to other host.
 */
$ipDetectPost    = http_build_query(['passwd' => $configIpPassword]);
$ipDetectPostLen = strlen($ipDetectPost);

$myIp = file_get_contents(
    $ipDetectUrl,
    false,
    stream_context_create(
        [
            'ssl'  => [
                'verify_peer'       => false,
                'verify_peer_name'  => false,
                'allow_self_signed' => true,
            ],
            'http' => [
                'method'  => 'POST',
                'header'  => "Connection: close\r\n" .
                             "Content-Type: application/x-www-form-urlencoded\r\n" .
                             "Content-Length: {$ipDetectPostLen}\r\n",
                'content' => $ipDetectPost
            ]
        ]
    )
);

if (empty($myIp) || $myIp == 'error') {
    throw new Exception("Invalid IP returned '{$myIp}'");
}
$dynUrl = sprintf(
    'https://dynupdate.no-ip.com/nic/update?hostname=%s&myip=%s', urlencode($configIpHost), urlencode($myIp)
);

// finally update NO-IP hostname IP address
$response = file_get_contents(
    $dynUrl,
    false,
    stream_context_create(
        [
            'http' => [
                'method' => 'GET',
                'header' => sprintf(
                    "Authorization: Basic %s\r\n",
                    base64_encode($configNoIpUsername . ':' . $configNoIpPassword)
                )
            ]
        ]
    )
);

printf("ip: %s, dyn response: %s\n", $myIp, $response);
exit(0);