Cloudflare DDNS with PHP (must use a cronjob)

cloudflareddns.php

<?php
// create your API Key at https://dash.cloudflare.com/profile/api-tokens
// Required permissions: Zone Settings:Read, Zone:Read, DNS:Edit (all under zone)
$apiKey = "";
$zoneName = "example.com";      // The domain (eg. example.com)
$recordName = "test.example.com";   // The full domain (eg. test.example.com)
$proxied = "false";     // Whether the domain should be proxied or not (https://support.cloudflare.com/hc/en-us/articles/200169156-Identifying-network-ports-compatible-with-Cloudflare-s-proxy)

/* ------------------------------------------ */

// Root URL for the Cloudflare APIs
$baseURL = "https://api.cloudflare.com/client/v4/";

// Init cURL
$curl = curl_init();
curl_setopt_array($curl, [
    CURLOPT_CUSTOMREQUEST => 'GET',
    CURLOPT_HTTPHEADER => array(
        'Authorization: Bearer ' . $apiKey,
        'Content-Type: application/json'
    ),
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_FORBID_REUSE   => true
]);

// Get zone name (zones?name=$zoneName)
curl_setopt($curl, CURLOPT_URL, $baseURL . "zones?name=$zoneName");
$res = curl_exec($curl);

$res = json_decode($res)->result;

if (count($res) > 0) {
    $res = $res[0];

    if (property_exists($res, 'id')) {
        // Save the zone ID
        $zoneID = $res->id;
    } else {
        print("An error has occurred while getting the zone infos!" . PHP_EOL);
        exit(1);
    }
} else {
    print("Cannot find the specified zone! Are you sure about the zone you set? (eg: example.com)");
    exit(1);
}

// Get the record ID and record content (zones/$zoneID/dns_records?type=A&name=$recordName)
curl_setopt($curl, CURLOPT_URL, $baseURL . "zones/$zoneID/dns_records?type=A&name=$recordName");
$res = curl_exec($curl);

$res = json_decode($res)->result;

// Check the result
if (count($res) > 0) {
    $res = $res[0];

    if (property_exists($res, 'id') && property_exists($res, 'content')) {
        // Save the record infos
        $recordID = $res->id;
        $recordContent = $res->content;     // the record content is the IP associated with the DNS
    } else {
        print("An error has occurred while getting the record infos!" . PHP_EOL);
        exit(1);
    }
} else {
    print("Cannot find the specified record! Are you sure about the record you set? (eg: test.example.com)");
    exit(1);
}


// Get the current IP of the machine
curl_setopt($curl, CURLOPT_URL, 'https://diagnostic.opendns.com/myip');
$res = curl_exec($curl);

$machineIP = $res;

// If the current IP is different from the IP saved in the DNS record, update it
if ($machineIP != $recordContent) {
    // Update the DNS record (zones/$zoneID/dns_records/$recordID)
    // This is a PUT request, not a GET request

    // Generate the data JSON that contains the new values for the DNS entry
    $data = '{"type":"A","name":"' . $recordName . '","content":"' . $machineIP . '","ttl":1,"proxied":' . $proxied . '}';

    // Tune cURL to send a PUT request with the data we generated
    curl_setopt_array($curl, [
        CURLOPT_URL => $baseURL . "zones/$zoneID/dns_records/$recordID",
        CURLOPT_CUSTOMREQUEST => 'PUT',
        CURLOPT_POSTFIELDS => $data
    ]);
    $res = curl_exec($curl);

    $res = json_decode($res);

    if (property_exists($res, 'success')) {
        if (!$res->success) {
            print("An error has occurred while updating the DNS!" . PHP_EOL);
            exit(1);
        }
    }
}