Recommendation: You should really avoid overriding woocommerce core files.
Instead you could use in this particular case the filter hook woocommerce_paypal_args, where you will be able to manipulate the arguments that are used in get_request_url() function (that will get the PayPal request URL for an order).
1) TESTING AND GETTING THE DATA SENT
Just to register and get the arguments sent to paypal, I have used the hook this way:
add_filter('woocommerce_paypal_args', 'custom_paypal_args', 10, 2 );
function custom_paypal_args ( $args, $order ) {
// Saving the data to order meta data (custom field)
update_post_meta( $order->get_id(), '_test_paypal', $args );
return $args;
}
Code goes in function.php file of your active child theme (or theme) or also in any plugin file.
Now I can get the data simply using this (setting the correct order ID):
$order_id = 648;
$data_sent_to_paypal = get_post_meta( $order_id, '_test_paypal' );
echo '<pre>'; print_r( $data_sent_to_paypal ); echo '</pre>';
Or in a hook ( visible in shop pages in this example only for admins ):
// Only visible on shop pages by admins
add_action( 'woocommerce_before_main_content', function(){
// Only visible by admins
if( ! current_user_can( 'manage_options' ) ) return;
$order_id = 648;
$data_sent_to_paypal = get_post_meta( $order_id, '_test_paypal' );
echo '<pre>'; print_r( $data_sent_to_paypal ); echo '</pre>';
}, 10, 0 );
This gives me an output like that (for 2 products and different quantities):
Array
(
[0] => Array
(
[cmd] => _cart
[business] => email@example.com
[no_note] => 1
[currency_code] => EUR
[charset] => utf-8
[rm] => 2
[upload] => 1
[return] => https://example.com/checkout/order-received/8877?key=wc_order_55445ndfgbulfdf&utm_nooverride=1
[cancel_return] => https://example.com/cart/?cancel_order=true&order=wc_order_55445ndfgbulfdf&order_id=8877&redirect&_wpnonce=34m7kl83455
[page_style] =>
[image_url] => https://example.com/wp-content/uploads/2012/06/logo.png
[paymentaction] => sale
[bn] => WooThemes_Cart
[invoice] => pp-8877
[custom] => {"order_id":8877,"order_key":"wc_order_55445ndfgbulfdf"}
[notify_url] => https://example.com/wc-api/WC_Gateway_Paypal/
[first_name] => John
[last_name] => Doe
[address1] => Test st.
[address2] =>
[city] => wef
[state] => AR
[zip] => 43242
[country] => US
[email] => myemail@example.com
[night_phone_a] => 078
[night_phone_b] => 653
[night_phone_c] => 6216
[no_shipping] => 1
[tax_cart] => 16.55
[item_name_1] => Test Product - Service
[quantity_1] => 1
[amount_1] => 71
[item_number_1] =>
[item_name_2] => Test Product 1
[quantity_2] => 1
[amount_2] => 66
[item_number_2] =>
[item_name_3] => Test Product 2
[quantity_3] => 1
[amount_3] => 120
[item_number_3] =>
[item_name_4] => Test Product 3
[quantity_4] => 1
[amount_4] => 45
[item_number_4] =>
)
)
As you can see now, with woocommerce_paypal_args you will be able to alter or remove any arguments.
There is always only one: 'item_name_1', 'quantity_1', 'amount_1' and 'item_number_1' with always index 1 sent to paypal.
2 MANIPULATING THE DATA SENT (example):
We can still use woocommerce_paypal_args, filter hook for example on 'item_name_1' key, to replace the items names by the order number, just as you want:
add_filter('woocommerce_paypal_args', 'custom_paypal_args', 10, 2 );
function custom_paypal_args ( $args, $order ) {
$$args_keys = array_keys($args);
$i = 0;
// Iterating through order items
foreach( $order->get_items() as $item_id => $item_product ){
$i++; // updating count.
if( ! empty($args["item_name_$i"]) ){
// Returning the order invoice in the item name
$args["item_name_$i"] = "invoice #" . $order->get_id();
}
}
return $args;
}
Code goes in function.php file of your active child theme (or theme) or also in any plugin file.
The code is tested and works on WooCommerce 3+
To finish: As you get the WC_Order object as argument in your hooked function, you can use it to get any data from the order, and manipulate as you like the data sent to paypal gateway.
See this related answer: How to get WooCommerce order details
