Pick List can print a shipping label and optionally include a barcode/QR based on a tracking/reference number.
Out of the box, Pick List does not connect directly to carrier APIs (UPS/FedEx/etc.) to purchase labels or fetch tracking numbers. Instead, Pick List can auto-fill the tracking/reference field if the value is stored on the WooCommerce order (order meta) by another plugin/service or custom code.
NOTE: From vs 2.6.2
Hook: cas_picklist_shipping_label_tracking_number
Use this filter to provide a tracking/reference number for the current order. If a non-empty value is returned:
- Include Barcode will be pre-checked
- the Tracking/Reference input will be pre-filled
- Pick List can use it to generate barcode/QR on the label
Filter signature
/**
* Provide tracking/reference number for Pick List shipping labels.
*
* @param string $tracking_number Tracking/reference number to encode as barcode/QR.
* @param int $order_id WooCommerce order ID.
* @param WC_Order|false $order WooCommerce order object (or false if not found).
*
* @return string Tracking/reference number (empty string = no prefill).
*/
apply_filters( 'cas_picklist_shipping_label_tracking_number', '', $order_id, $order );
Example 1: Read tracking number from a custom order meta key
If another plugin saves tracking to a known meta key (example: _tracking_number):
add_filter( 'cas_picklist_shipping_label_tracking_number', function( $tracking, $order_id, $order ) {
$value = get_post_meta( $order_id, '_tracking_number', true );
return is_string( $value ) ? trim( $value ) : '';
}, 10, 3 );
Example 2: Try multiple common meta keys (best-effort)
Useful when you are not sure which plugin writes the tracking number, or you support multiple setups:
add_filter( 'cas_picklist_shipping_label_tracking_number', function( $tracking, $order_id, $order ) {
$candidates = [
'_tracking_number',
'tracking_number',
'_aftership_tracking_number',
];
foreach ( $candidates as $key ) {
$value = get_post_meta( $order_id, $key, true );
if ( is_string( $value ) && '' !== trim( $value ) ) {
return trim( $value );
}
}
return '';
}, 10, 3 );
Example 3: Read tracking from an order item / shipping item meta
Some shipping integrations store tracking on shipping items rather than the order itself. This example loops shipping items and reads a meta key:
add_filter( 'cas_picklist_shipping_label_tracking_number', function( $tracking, $order_id, $order ) {
if ( ! $order instanceof WC_Order ) {
$order = wc_get_order( $order_id );
}
if ( ! $order ) {
return '';
}
foreach ( $order->get_items( 'shipping' ) as $item_id => $item ) {
$value = $item->get_meta( 'tracking_number', true );
if ( is_string( $value ) && '' !== trim( $value ) ) {
return trim( $value );
}
}
return '';
}, 10, 3 );
Notes and best practices
- Pick List will only prefill what you return from the filter. If tracking is not stored on the order yet, the field remains empty.
- The tracking value should be a string (numbers are fine, but return them as a string).
- Make sure tracking is stored before you open the shipping label dialog (i.e., after label purchase/creation).
- If your workflow uses UPS rates at checkout but purchases labels elsewhere (ShipStation, UPS WorldShip, etc.), ensure the tracking number is written back to the WooCommerce order (meta) to enable auto-fill.
