How to get the domain of the one who tried file_get_contens to pick up the JSON?

Question

PHP

Hello everyone, there is such a script, it checks if there is a domain in the database

$domainCheck = file_get_contents('http://site.ru/check/check.php?domain='.$_SERVER['HTTP_REFERER'].');
if($domainCheck != '1'){exit('LICENSE IS NOT ACTIVATED');}

It is necessary that if someone tries to get json through file_get_contents, which, in the continuation of this script from above, receives the domain from which they access the site

Answer 1

$hostname = gethostbyaddr($_SERVER['REMOTE_ADDR']);
echo $hostname;

If it sits under some service (cloudflare), then just forget it. Such checks require other tools.