'upload' => (int)(sizeof($order->products) > 0),
'currency_code' => $my_currency,
// 'paypal_order_id' => $paypal_order_id,
//'no_note' => '1',
//'invoice' => '',
);
// if line-item info is invalid, use aggregate:
if (sizeof($optionsLineItems) > 0) $optionsAggregate = $optionsLineItems;
// prepare submission
$options = array_merge($optionsCore, $optionsCust, $optionsPhone, $optionsShip, $optionsTrans, $optionsAggregate);
ipn_debug_email('Keys for submission: ' . print_r($options, true));
if(sizeof($order->products) > 0){
$options['cmd'] = '_cart';
for ($i=0, $n=sizeof($order->products); $i<$n; $i++) {
$options['item_name_'. (string)($i+1)] = $order->products[$i]['name'];
$options['item_number_'. (string)($i+1)] = $order->products[$i]['dhisys_web_order_number'];
$options['amount_'. (string)($i+1)] = number_format((float)$order->products[$i]['final_price'],2);
$options['quantity_'. (string)($i+1)] = $order->products[$i]['qty'];
}
}
// build the button fields
foreach ($options as $name => $value) {
// remove quotation marks
$value = str_replace('"', '', $value);
// check for invalid chars
if (preg_match('/[^a-zA-Z_0-9]/', $name)) {
ipn_debug_email('datacheck - ABORTING - preg_match found invalid submission key: ' . $name . ' (' . $value . ')');
break;
}
// do we need special handling for & and = symbols?
//if (strpos($value, '&') !== false || strpos($value, '=') !== false) $value = urlencode($value);
$buttonArray[] = zen_draw_hidden_field($name, $value);
}
$_SESSION['paypal_transaction_info'] = array($this->transaction_amount, $this->transaction_currency);
$process_button_string = implode("n", $buttonArray) . "n";
return $process_button_string;
}
}
?>
3. 在checkout_success页面中显示pay now按钮。打开文件"includes/modules/pages/checkout_success/header.php"，在文件的末尾添加下面的代码（如果你已经掌握zen-cart中的通知者/观察者模式，并且又不想破坏zen-cart核心代码的话，也可以创建一个观察类来监听NOTIFY_HEADER_END_CHECKOUT_SUCCESS来实现）。
require_once(DIR_WS_CLASSES . 'order.php');
require_once(DIR_WS_CLASSES . 'payment.php');
$payment_modules = new payment($orders->fields['payment_module_code']);
打开文件"includes/modules/templates/template_default/templates/tpl_checkout_success_default.php"，并在适当的位置加上如下的代码，这里对订单的状态进行了一个判断，当只有订单的状态在未付款状态，才显示该按钮，
<div id="pay_now">
<?php
//&& $orders->fields['orders_status'] == '1'
if(isset($payment_modules->paynow_action_url) && $payment_modules->paynow_action_url != ''&& $orders->fields['orders_status'] == '1'){
echo('<fieldset id="csNotifications">');
echo('<legend>'.TEXT_PAYNOW.'</legend>');
