Sailthru_Client::receiveOptoutPost PHP Method

    public function receiveOptoutPost()
    {
        $params = $_POST;
        foreach (['action', 'email', 'sig'] as $k) {
            if (!isset($params[$k])) {
                return false;
            }
        }
        if ($params['action'] != 'optout') {
            return false;
        }
        $sig = $params['sig'];
        unset($params['sig']);
        if ($sig != Sailthru_Util::getSignatureHash($params, $this->secret)) {
            return false;
        }
        return true;
    }