PHP首部认证

<?php
// User name and password for authentication
$username = 'rock';
$password = 'roll';

if (!isset($_SERVER['PHP_AUTH_USER']) || !isset($_SERVER['PHP_AUTH_PW']) ||
($_SERVER['PHP_AUTH_USER'] != $username) || ($_SERVER['PHP_AUTH_PW'] != $password)) {
// The user name/password are incorrect so send the authentication headers
header('HTTP/1.1 401 Unauthorized');
header('WWW-Authenticate: Basic realm="Guitar Wars"');
exit('<h2>Guitar Wars</h2>Sorry, you must enter a valid user name and password to access this page.');
}
?>