Fritz!Box DynDNS update script for Cloudflare

upd.php

<?php
  // Fritz!Box update URL: https://example.com/upd.php?key=<pass>&zone=<domain>&ipv4=<ipaddr>&a=[records to update]
  // Replace [records to update] in the url.
  // If you want to update multiple records of your zone, just add them comma separated: '&a=sub,sub2,*,@'
  // Optionally you can update AAAA records by appending '&ipv6=<ip6addr>&aaaa=[records to update]' to the url.
  // If no AAAA record is defined but ipv6 is used, it will update both ip4 and ip6 defined for A records.

  // $_SERVER['REMOTE_ADDR'] no longer works as FritzOS 7.50 started using IPv6
  $key = $_GET['key'] ?? NULL;
  $zone = $_GET['zone'] ?? NULL;
  $a_hosts = isset($_GET['a']) ? explode(',', $_GET['a']) : array();
  $ip_v4 = $_GET['ipv4'] ?? NULL;

  $aaaa_hosts = isset($_GET['aaaa']) ? explode(',', $_GET['aaaa']) : array(); //optional
  $ip_v6 = $_GET['ipv6'] ?? NULL; //optional

  $api_base = 'https://api.cloudflare.com/client/v4/zones';

  function printHelp()
  {
    $file_name = basename($_SERVER["SCRIPT_FILENAME"]);
    $params = htmlspecialchars('?key=<pass>&zone=<domain>&ipv4=<ipaddr>&a=') . '<i>[records to update]</i>';
    $optional = htmlspecialchars('&ipv6=<ip6addr>&aaaa=') . '<i>[records to update]</i>';

    echo "Fritz!Box update URL: <b>https://{$_SERVER['HTTP_HOST']}/{$file_name}{$params}</b><br>";
    echo 'Replace <b><i>[records to update]</i></b> in the url.<br>';
    echo 'If you want to update multiple records of your zone, just add them comma separated: <i>\'&a=sub,sub2,*,@\'</i><br>';
    echo "Optionally you can update AAAA records by appending <b>'{$optional}'</b> to the url.<br>";
    echo 'If no AAAA record is defined but ipv6 is used, it will update both ip4 and ip6 defined for A records.';
  };

  function transformToRecordNames(&$hosts, $zone_name)
  {
    if ($hosts == NULL)
    {
      return;
    }

    foreach ($hosts as &$host)
    {
      $host = $host == '@' ? $zone_name : $host . '.' . $zone_name;
    }
    unset($host);
    unset($hosts);
  }

  if(empty($_GET))
  {
    printHelp();
    return http_response_code(200);
  }

  if ($key == NULL || $zone == NULL || empty($a_hosts) || $ip_v4 == NULL || (!empty($aaaa_hosts) && $ip_v6 == NULL))
  {
    printHelp();
    return http_response_code(400);
  }

  transformToRecordNames($a_hosts, $zone);
  transformToRecordNames($aaaa_hosts, $zone);

  if ($aaaa_hosts == NULL && $ip_v6 != NULL)
  {
    $aaaa_hosts = $a_hosts;
  }


  // get zone identifier
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $api_base . '?name=' . $zone . '&status=active');
  curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, FALSE);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array('Authorization: ' . 'Bearer ' . $key, 'Content-Type: application/json'));
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);

  $response = json_decode(curl_exec($ch));
  curl_close($ch);

  if($response -> success == FALSE)
  {
    foreach ($response -> errors as $error)
    {
      echo 'Error fetching zone identifier: ';
      echo $error -> message;
      echo '<br>';

      error_log('Error fetching zone identifier: ' . $error -> message);

      if(isset($error -> error_chain))
      {
        foreach ($error -> error_chain as $error_detail)
        {
          error_log($error_detail -> message);
          echo $error_detail -> message;
          echo '<br>';
        }
      }
    }
    return http_response_code(500);
  }

  if(empty($response -> result))
  {
    echo 'Error fetching zone identifier:<br>Check if you have access to the given zone.';
    error_log('Error fetching zone identifier: Check if you have access to the given zone.');
    return http_response_code(500);
  }

  $zone_id = $response -> result[0] -> id;

  
  // get record identifier
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $api_base . '/' . $zone_id . '/dns_records?type=A,AAAA');
  curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, FALSE);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array('Authorization: ' . 'Bearer ' . $key, 'Content-Type: application/json'));
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);

  $response = json_decode(curl_exec($ch));
  curl_close($ch);

  if($response -> success == FALSE)
  {
    foreach ($response -> errors as $value)
    {
      echo 'Error fetching record identifier:<br>';
      echo $value -> message;
      echo '<br>';
      error_log('Error fetching record identifier: ' . $value -> message);
    }
    return http_response_code(500);
  }

  $records = array();
  foreach ($response -> result as $value)
  {
    if(($value -> type == 'A' && in_array($value -> name, $a_hosts)) || ($value -> type == 'AAAA' && in_array($value -> name, $aaaa_hosts)))
    {
      array_push($records, $value);
    }
  }

  if (count($records) != count($a_hosts) + count($aaaa_hosts))
  {
    echo 'Error updating records:<br>';
    echo 'Check if the records you are trying to update already exist in the given zone.';
    error_log('Error updating records: Check if the records you are trying to update already exist in the given zone.');
    return http_response_code(500);
  }

  
  // update record(s)
  $mh = curl_multi_init();
  $ch_arr = array();
  $results = array();

  foreach ($records as $rec)
  {
    $record_name = $rec -> name;
    $record_id = $rec -> id;
    $record_type = $rec -> type;
    $record_content = $record_type == 'A' ? $ip_v4 : $ip_v6;
    $put_data = array('type' => $record_type, 'name' => $record_name, 'content' => $record_content, 'ttl' => 60, 'proxied' => FALSE ); 
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $api_base . '/' . $zone_id . '/dns_records/' . $record_id);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, FALSE);
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "PUT");
    curl_setopt($ch, CURLOPT_HTTPHEADER, array('Authorization: ' . 'Bearer ' . $key, 'Content-Type: application/json'));
    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($put_data));
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);

    array_push($ch_arr, $ch);
    curl_multi_add_handle($mh, $ch);
  }

  $running = null;

  do
  {
    curl_multi_exec($mh, $running);
  }
  while($running > 0);

  foreach ($ch_arr as $ch)
  {
    array_push($results, json_decode(curl_multi_getcontent($ch)));
    curl_multi_remove_handle($mh, $ch);
  }

  curl_multi_close($mh);
  foreach ($results as $result)
  {
    if($result -> success == FALSE)
    {
      foreach ($result -> errors as $index => $value)
      {
        echo 'Error updating record:<br>';
        echo $value -> message;
        echo '<br>';
        error_log('Error updating record: ' . $value -> message);
      }
      return http_response_code(500);
    }
  }

  echo 'SUCCESS';
?>

I'm having some problem: frtizbox reports "Errore Dynamic DNS: l'aggiornamento Dynamic DNS ha avuto esito positivo, ma alla fine si è verificato un errore nella risoluzione DNS."
Checking on Cloudflare Dash the IP adress has not been modified!
I'm trying to update a single subdomain!
Thanks so much

Are you using that exact URL scheme /upd.php?email=<username>&key=<pass>&hosts=<domain>?
Does your PHP server support curl and have you checked your server logs?