w1

    public function api()
    {
        if (!isset($_POST["WMI_SIGNATURE"]))
          return "WMI_RESULT=" . strtoupper('Retry') . "&WMI_DESCRIPTION="
           .urlencode("Отсутствует параметр WMI_SIGNATURE");

        if (!isset($_POST["WMI_PAYMENT_NO"]))
          return "WMI_RESULT=" . strtoupper('Retry') . "&WMI_DESCRIPTION="
           .urlencode("Отсутствует параметр WMI_PAYMENT_NO");

        if (!isset($_POST["WMI_ORDER_STATE"]))
          return "WMI_RESULT=" . strtoupper('Retry') . "&WMI_DESCRIPTION="
           .urlencode("Отсутствует параметр WMI_ORDER_STATE");

        if (strtoupper($_POST["WMI_ORDER_STATE"]) != "ACCEPTED")
          return "WMI_RESULT=" . strtoupper('Retry') . "&WMI_DESCRIPTION="
           .urlencode("Случилось что-то странное, пришло неизвестное состояние заказа ". $_POST["WMI_ORDER_STATE"]);

        foreach($_POST as $name => $value)
        {
            if ($name !== "WMI_SIGNATURE") $params[$name] = urldecode($value);
        }
        uksort($params, "strcasecmp");
        $values = "";
        foreach($params as $name => $value)
        {
            $values .= $value;
        }
        $skey = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
        $signature = base64_encode(pack("H*", md5($values . $skey)));
        if($signature != $_POST["WMI_SIGNATURE"])
          return "WMI_RESULT=" . strtoupper('Retry') . "&WMI_DESCRIPTION="
           .urlencode("Неверная подпись " . $_POST["WMI_SIGNATURE"]);

        return "WMI_RESULT=" . strtoupper('Ok') . "&WMI_DESCRIPTION="
         .urlencode('Заказ #' . $_POST['WMI_PAYMENT_NO'] . ' оплачен!');
    }