I used tor this way:
$proxy = "127.0.0.1";
$port = "9050";
$url = "https://mydomain.onion/input.php";
$ch = curl_init();
curl_setopt ($ch, CURLOPT_URL, $url);
curl_setopt ($ch, CURLOPT_HEADER, 0);
curl_setopt ($ch, CURLOPT_PROXYTYPE, 7 );
curl_setopt ($ch, CURLOPT_PROXY, $proxy.':'.$port );
ob_start();
curl_exec ($ch);
curl_close ($ch);
$result = ob_get_contents();
ob_end_clean();
var_dump($result);