Get the domain name which use my URL in iFrame

Question

I have developed a service in which users can use this service on their websites, they should put a global URL in the iframe tag in their websites.

Now I should check the domain name which this iframe loaded on that domain to verify is this site has permission to use this iframe or not.

So I wrote middleware in my controller but I'm not sure how I can get the domain address where the iframe is located. is used $request->headers->get('origin') but it's not works.

public function __construct(Request $request)
    {

        $this->middleware(function ($request, $next) {
            if (!empty($this->trust_domains)) {
                $domains = explode(',', $this->trust_domains);
                $request_host = parse_url($request->headers->get('origin'), PHP_URL_HOST);
                if (!in_array($request_host, $domains)) {
                    return response('You don\'t have access to this section', 403);
                }
            }
            return $next($request);
        });

    }