Basic Auth

<?php

$user = empty($_SERVER['PHP_AUTH_USER']) ? NULL : $_SERVER['PHP_AUTH_USER'];
$pass = empty($_SERVER['PHP_AUTH_PW']) ? NULL : $_SERVER['PHP_AUTH_PW'];
if (empty($user)) {
    header('WWW-Authenticate: Basic realm="Mi dominio"');
    header('HTTP/1.0 401 Unauthorized');
    header('Content-Type: text/plain; charset=utf-8');
    echo 'Noup. No es así.';
    exit;
}

if ($user !== 'admin' || $pass !== 'admin') {
    header('HTTP/1.0 401 Unauthorized');
    header('Content-Type: text/plain; charset=utf-8');
    echo "Le has pifiado la contraseña.";
    exit;
}

header('Content-Type: text/plain; charset=utf-8');
echo "Hell yeah!!";