/**
* Creates and returns the payment component of a PayPal Digital Goods NVP API request.
*
* PayPal requires the category component for all items in a digital goods purchase to be set as Digital.
* This function specifies that all goods are digital, then calls @see parent::add_payment() to create
* the rest of the API request (which is the same as a vanilla Express Checkout request).
*
* @uses parent::add_payment() to create non digital goods components of the request.
* @return Array An array of name value pairs for each element representing a payment in a PayPal Digital Goods NVP API request.
*/
protected function add_payment($action)
{
$request = parent::add_payment($action);
// Make sure PayPal knows all goods are digital
for ($i = 0; $i < count($this->options['items']); $i++) {
$request += array("L_PAYMENTREQUEST_0_ITEMCATEGORY{$i}" => 'Digital');
}
return $request;
}
