/*
addEventHandler(
    "main", 
    "OnProlog", 
    array( 
        "CBitrixReCaptcha", 
        "initJS" 
    ) 
);
*/
/*
//Обработчик регистрации
\Bitrix\Main\EventManager::getInstance()->addEventHandler(
    "main", 
    "OnBeforeUserRegister", 
    array( 
        "CBitrixReCaptcha", 
        "checkRegistration" 
    ) 
);
*/
class CBitrixReCaptcha {
    /*
        Секретные ключи
    */
    private static $secret = "6LfY7tsaAAAAABXy3B8Q_OuOGkn0rBkHFgAC80qL"; //Секретный ключ
    private static $siteKey = "6LfY7tsaAAAAAGhpl8oUUlFzOaob0TQ5rz_ffifu"; //Ключ сайта
    private static $permissibleScore = 0.5; //допустимая оценка    
    private static $hideBadge = "N";
    const SITE_VERIFY_URL = 'https://www.google.com/recaptcha/api/siteverify';    
    public static function verify($token)
    {
        $errorObject =
        [
            'success' => false,
            'score' => false,
            'isSuccess' => false,
            'hostname' => null,
            'action' => null,
            'challenge_ts' => null,
            'error_codes' => ['Empty token.']
        ];
        if (empty($token)) return $errorObject;
        $data = self::submit($token);
        if (!$data) return $errorObject;
        $success = isset($data['success']) ? $data['success'] : false;
        $score = isset($data['score']) ? $data['score'] : false;
        $isSuccess = $success && $score !== false ? self::$permissibleScore <= $score : false;
        $hostname = isset($data['hostname']) ? $data['hostname'] : null;
        $action = isset($data['action']) ? $data['action'] : null;
        $challenge_ts = isset($data['challenge_ts']) ? $data['challenge_ts'] : null;
        $error_codes = $data['error-codes'];
        return
        [
            'success' => $success,
            'score' => $score,
            'isSuccess' => $isSuccess,
            'hostname' => $hostname,
            'action' => $action,
            'challenge_ts' => $challenge_ts,
            'error_codes' => $error_codes
        ];
    }
    public static function submit($token)
    {
        $params = ['secret' => self::$secret, 'response' => $token];
        $params = http_build_query($params, '', '&');
        $curl = curl_init(self::SITE_VERIFY_URL);
        curl_setopt_array($curl,
        [
            CURLOPT_POST => true,
            CURLOPT_POSTFIELDS => $params,
            CURLOPT_HTTPHEADER => ['Content-Type: application/x-www-form-urlencoded'],
            CURLINFO_HEADER_OUT => false,
            CURLOPT_HEADER => false,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_SSL_VERIFYPEER => true
        ]);
        $result = curl_exec($curl);
        curl_close($curl);
        return json_decode($result, true);
    }
    /**
     * Подключаем JS скрипты для reCaptcha v3
     */
    public function initJS()
    {
        $Asset = \Bitrix\Main\Page\Asset::getInstance();
        $siteKey = self::$siteKey;
        $hideBadge = self::$hideBadge;
        if (empty($siteKey)) return true;
        $Asset-&gt;addString('<script src="https://www.google.com/recaptcha/api.js?render='. $siteKey .'"></script>');
        $Asset-&gt;addString('<script>window.recaptcha = { siteKey: "'. $siteKey .'", tokenLifeTime: 120 };</script>'); // время жизни токена в секундах (2 минуты максимальное время жизни токена)
        $Asset-&gt;addString('<script src="/include/recaptcha.js"></script>');
        if ($hideBadge == 'Y')
            $Asset-&gt;addString('<style>.grecaptcha-badge {display: none;}</style>');
    }
    /**
     * Проверка при регистрации пользователя
     */
    public function checkRegistration(&amp;$arArgs)
    {
        return self::checkSpam();
    }
    /**
     * Основной метод проверки капчи
     */
    public function checkSpam()
    {
        global $APPLICATION;
        // из админки не проверяем
        // if (preg_match('/^\/bitrix\/admin\/.*$/i', $APPLICATION-&gt;GetCurPage())) return true;
        $isError = false;
        if( !$_REQUEST['recaptcha_token'] &amp;&amp; $_POST['recaptcha_token'] ) {
            $_REQUEST['recaptcha_token'] = $_POST['recaptcha_token'];
        }
        $recaptcha_token = $_REQUEST['recaptcha_token'];
        if( isset($recaptcha_token) &amp;&amp; !empty($recaptcha_token) ) {
            $secretKey = self::$siteKey;
            $permissibleScore = self::$permissibleScore;
            $response = self::verify($recaptcha_token);
            //echo "<pre>"; print_r($response); echo "</pre>";
            if ( $response['isSuccess'] &amp;&amp; ( floatval($response['score']) &gt;= $permissibleScore ) ) {
                return true;
            }
        }
        return false;
        /*
        if ($isError)
        {
            $errorMessage = "Ошибка проверки";
            $APPLICATION-&gt;ThrowException($errorMessage);
            return false;
        }
        */
    }
}//CBitrixReCaptcha<pre>[RuntimeException] 
Could not start session because headers have already been sent. &quot;/home/bitrix/www/bitrix/php_interface/recaptcha.php&quot;:1. (0)
/home/bitrix/www/bitrix/modules/main/lib/session/session.php:151
#0: Bitrix\Main\Session\Session-&gt;start
	/home/bitrix/www/bitrix/modules/main/lib/session/kernelsessionproxy.php:47
#1: Bitrix\Main\Session\KernelSessionProxy-&gt;start
	/home/bitrix/www/bitrix/modules/main/include.php:180
#2: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog_before.php:19
#3: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog.php:10
#4: require_once(string)
	/home/bitrix/www/bitrix/header.php:1
#5: require(string)
	/home/bitrix/www/courses/index.php:2
#6: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:184
#7: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2
----------
</pre>