PHP开发中如何处理网站防护和防火墙

$username = filter_input(INPUT_POST, 'username', FILTER_SANITIZE_STRING);

$password = password_hash($password, PASSWORD_DEFAULT);
if (password_verify($inputPassword, $storedPassword)) {
     // 验证通过
} else {
     // 验证失败
}

session_start();
ini_set("session.cookie_httponly", 1);

$allowed_ips = array('127.0.0.1', '10.0.0.1');
$client_ip = $_SERVER['REMOTE_ADDR'];
if (!in_array($client_ip, $allowed_ips)) {
    header('HTTP/1.0 403 Forbidden');
    die('Access denied.');
}

$key = 'ip_' . $_SERVER['REMOTE_ADDR'];
$current_time = time();
$expire_time = 60; // 限制为每分钟只能发起一次请求
$limit = 5; // 限制为每分钟最多发起5次请求

$cache = new Redis();
$cache->connect('127.0.0.1', 6379);
if (!$cache->exists($key)) {
    $cache->set($key, 1, $expire_time);
} else {
    $cache->incr($key);
}
$count = $cache->get($key);
if ($count > $limit) {
    header('HTTP/1.0 429 Too Many Requests');
    die('Request limit exceeded.');
}