friendica/mod/webfinger.php

<?php

use Friendica\App;
use Friendica\Network\Probe;

function webfinger_content(App $a) {

	if (!local_user()) {
		http_status_exit(403,
				["title" => t("Public access denied."),
					"description" => t("Only logged in users are permitted to perform a probing.")]);
		killme();
	}

	$o .= '<h3>Webfinger Diagnostic</h3>';

	$o .= '<form action="webfinger" method="get">';
	$o .= 'Lookup address: <input type="text" style="width: 250px;" name="addr" value="' . $_GET['addr'] .'" />';
	$o .= '<input type="submit" name="submit" value="Submit" /></form>';

	$o .= '<br /><br />';

	if(x($_GET,'addr')) {
		$addr = trim($_GET['addr']);
		$res = Probe::lrdd($addr);
		$o .= '<pre>';
		$o .= str_replace("\n",'<br />',print_r($res,true));
		$o .= '</pre>';
	}
	return $o;
}