Catch data from CSP: report-uri

Hi guys how can I catch the data from CSP: report-uri? I already active it in the config App and set the report URL in ContentSecurityPolicy.php like this:
 

Code:

public $reportURI = '/csp-violation-report-endpoint';

at my Route.php I already define it like this:

Code:

$routes->add('csp-violation-report-endpoint', 'Home::csp');

And my controller like this:

    public function csp()
    {
        log_message('info', 'CSP violation trigerred');
        $json_data = file_get_contents('php://input');

        $json_data = json_encode($json_data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
        $current_domain = preg_replace('/www\./i', '', $_SERVER['SERVER_NAME']);
        $message = "The following Content-Security-Policy violation occurred on " .
            $current_domain . ":\n\n" .
            $json_data .
            "\n\nFurther CPS violations will be logged to the following log file, but no further email notifications will be sent until this log file is deleted:\n\n";

        log_message('error', $message);
    }

But I don't get anything? is it something wrong or did I miss here? Thanks.