只是无法让我的IPN使用多个项目

Question

IPN用于将订单详细信息放入，等等。但是我试图将item_numbers返回到MySQL表格中......我无法看到我出错的地方。而且我无法解决如何记录我的_POST。我猜测它只是没有找到任何item_numbers ......但我无法获得_POST变量来查看究竟是什么进来。

$oID = $_POST['txn_id']; // joins o and oItems
  $n = 1;
  while (TRUE) 
    {
    if (isset(${"_POST['item_number" . $n . "']"}))
        {$item_numbers[] = ${"_POST['item_number" . $n . "']"};}
    else {break;}
    $n++;
    }
  $n = 1;
  foreach ($item_numbers as $key => $item_number)
    {

        $pID = $item_number;
        $pAmount_o = ${"_POST['mc_gross_" . $n . "']"};
        $pQuantity = ${"_POST['quantity" . $n+1 . "']"};
        $q = "INSERT INTO `oItems` (ID, pID, pAmount_o, oID, pQuantity) VALUES ('', '$pID', '$pAmount_o', '$oID', '$pQuantity')";
        mysqli_query($c, $q); 
        $n++;
        }

我不能告诉你这个日志发生了什么...... :(

$t = time();
$post = serialize(print_r($_POST));
$q = "INSERT INTO `ipnLogs` (`logID`, `logTime`, `logType`, `logContent`) VALUES ('', '$t', '_POST', '$post')";
mysqli_query($c, $q);