Paypal module passes STORE_NAME instead of item

The PayPal payment module (paypal.php,v 1.39 2003/01/29) for OSCommerce does not pass a meaningful item description to Paypal as a transaction is processed. Instead, the developer of this module programmed it to send the name of your store instead:

tep_draw_hidden_field('item_name', STORE_NAME) .

The result is that when the transaction completes, Paypal sends the store owner an email notification, unhelpfully describing the item purchased as "[name of your store]".

We will fix this by changing the code in the payment module to send a better description for that field. While we're at it, we'll change the code to better support stores selling multiple items in one transaction because this Paypal module comes "out of the box" designed more for single item purchase. When multiple items are purchased, this module just gives an aggregate description of the whole transaction, without any detail of what exatly was purchased.

To fix both of these problems, use the patch file below, or edit (path to your store)/includes/modules/payment/paypal.php and jump down to this function:

function process_button() {

find the line that looks like:

$process_button_string = tep_draw_hidden_field

and insert a comment marker right before it:

/*
$process_button_string = tep_draw_hidden_field

and then go down a few more lines from there until you get to the one that has a semicolon at the end, instead of a period. After that line, insert an ending comment marker:

*/

Now, after your ending comment marker (commenting out the original code makes it not operate anymore, while preserving it for reference), insert the following:

 # Multiple item payment, P. 86 of 
 # https://www.paypal.com/en_US/pdf/PP_WebsitePaymentsStandard_IntegrationGuide.pdf

$process_button_string = tep_draw_hidden_field('cmd', '_cart') .
      tep_draw_hidden_field('upload', '1') .
      tep_draw_hidden_field('business', MODULE_PAYMENT_PAYPAL_ID) .
      tep_draw_hidden_field('handling_cart', number_format($order->info['shipping_cost'] * $currencies->get_value($my_currency), $currencies->get_decimal_places($my_currency))) .
      tep_draw_hidden_field('currency_code', $my_currency) .
      tep_draw_hidden_field('custom', $order->info['comments']) .
      tep_draw_hidden_field('return', tep_href_link(FILENAME_CHECKOUT_PROCESS, '', 'SSL')) .
      tep_draw_hidden_field('cancel_return', tep_href_link(FILENAME_CHECKOUT_PAYMENT, '', 'SSL'));

 # add individual items and amounts to keep in PP transaction history and notices

 $i=0;
 foreach($order->products as $key => $arr)
 {
     $i++;
     $process_button_string .= tep_draw_hidden_field("item_name_$i",  $arr["qty"] ." ". $arr["name"]) .
                               tep_draw_hidden_field("amount_$i", $arr["qty"] * $arr["final_price"]);

 } 

Save the file, and now every payment transaction from your OS-Commerce store that is processed with this payment module will send Paypal the item name and price of each item your customer is purchasing. The "handling_cart" field adds a single shipping fee to the entire order. If you want to charge shipping amount per item, see the manual mentioned in the code comment above and use multiple "shipping_X" fields inside the foreach loop instead.

Once you make this change, the email notices that Paypal sends to the shop owner after each purchase will contain a detailed list of what was bought. Both the customer and the merchant will also have detailed records of the itemized list stored in the Paypal transaction history. This is much better than just one aggregate item with a total price and no Paypal record of what the order consisted of.

Using my patch file to make the above change.
You can skip a whole lot of manual editting if you download the patchfile included below, save it as paypal.patch in the same directory as the original paypal.php file, and then run the following shell command:

patch -b paypal.php < paypal.patch

The -b option will make a backup copy of the original file, just in case.

Click to show patch

Hide Patch

--- orig.php    Wed Sep 20 22:49:53 2006
+++ paypal.php  Wed Sep 20 23:05:07 2006
@@ -83,6 +83,8 @@
       if (!in_array($my_currency, array('CAD', 'EUR', 'GBP', 'JPY', 'USD'))) {
         $my_currency = 'USD';
       }
+
+/*
       $process_button_string = tep_draw_hidden_field('cmd', '_xclick') .
                                tep_draw_hidden_field('business', MODULE_PAYMENT_PAYPAL_ID) .
                                tep_draw_hidden_field('item_name', STORE_NAME) .
@@ -91,6 +93,30 @@
                                tep_draw_hidden_field('currency_code', $my_currency) .
                                tep_draw_hidden_field('return', tep_href_link(FILENAME_CHECKOUT_PROCESS, '', 'SSL')) .
                                tep_draw_hidden_field('cancel_return', tep_href_link(FILENAME_CHECKOUT_PAYMENT, '', 'SSL'));
+*/
+
+# Multiple item payment, P. 86 of
+# https://www.paypal.com/en_US/pdf/PP_WebsitePaymentsStandard_IntegrationGuide.pdf
+
+$process_button_string = tep_draw_hidden_field('cmd', '_cart') .
+                         tep_draw_hidden_field('upload', '1') .
+                         tep_draw_hidden_field('business', MODULE_PAYMENT_PAYPAL_ID) .
+                         tep_draw_hidden_field('handling_cart', number_format($order->info['shipping_cost'] * $currencies->get_value($my_currency),
+                                               $currencies->get_decimal_places($my_currency))) .
+                         tep_draw_hidden_field('currency_code', $my_currency) .
+                         tep_draw_hidden_field('custom', $order->info['comments']) .
+                         tep_draw_hidden_field('return', tep_href_link(FILENAME_CHECKOUT_PROCESS, '', 'SSL')) .
+                         tep_draw_hidden_field('cancel_return', tep_href_link(FILENAME_CHECKOUT_PAYMENT, '', 'SSL'));
+
+# add individual items and amounts to keep in PP transaction history and notices
+
+$i=0;
+foreach($order->products as $key => $arr)
+{
+    $i++;
+    $process_button_string .= tep_draw_hidden_field("item_name_$i", $arr["qty"] ." ". $arr["name"]) .
+                              tep_draw_hidden_field("amount_$i", $arr["qty"] * $arr["final_price"]);
+}

       return $process_button_string;
     }