php防止恶意注册

// 使用更复杂的验证码生成库，例如 php-captcha
require 'vendor/autoload.php';

use Captcha\Captcha;

$captcha = new Captcha();
$image = $captcha->generateImage();
$image->show();

// 在表单提交时验证验证码
if ($_POST['captcha'] !== $_SESSION['captcha']) {
    die('验证码错误');
}

// 设置合理的IP限制时间窗口和次数
$ip = $_SERVER['REMOTE_ADDR'];
$key = "register_limit:$ip";
$current = strtotime("now");
$window = 3600; // 1小时
$limit = 5; // 每小时最多注册5次

$current_limit = (int) $redis->get($key);
if ($current_limit >= $limit && ($current - $redis->ttl($key) < $window)) {
    die('注册过于频繁，请稍后再试');
} else {
    if ($redis->incr($key) === 1) {
        $redis->expire($key, $window);
    }
}