“Invalid Order” error when generating second custom PDF template

Question

I’m using the WooCommerce PDF Invoices & Packing Slips plugin by WP Overnight.

I’ve successfully:

Created a second custom PDF template (a voucher version without prices).
Added a button on the Thank You page to download that second template.

Everything appears to be set up correctly — but when I click the new button, I get this error:

Invalid Order The order ID being passed is correct (I double-checked the value and it matches the order that just completed).

What I’ve done:

Created the second template under my child theme: wp-content/themes/child-theme/woocommerce/pdf/voucher.php And registered it via filter adding a custom button on Thank you page:

add_action('woocommerce_thankyou', 'add_voucher_pdf_button', 20);
function add_voucher_pdf_button($order_id) {
    if (!$order_id) return;
    
    $order = wc_get_order($order_id);
    if (!$order) return;

    // Nonce for security, must match the document type (invoice)
    $nonce = wp_create_nonce('generate_wpo_wcpdf');
    
    // Build the correct AJAX URL
    $pdf_url = add_query_arg(array(
        'action'       => 'generate_wpo_wcpdf',
        'document'     => 'invoice', // keep as invoice, since voucher isn’t a registered type
        'order_ids'    => $order->get_id(),
        'voucher_pdf'  => 1,
        '_wpnonce'     => $nonce,
    ), admin_url('admin-ajax.php'));
    
    echo '<a href="' . esc_url($pdf_url) . '" target="_blank" class="button alt" style="margin-top:20px;">Download Voucher PDF</a>';
}


add_filter('wpo_wcpdf_template_file', 'load_voucher_template_conditionally', 10, 3);
function load_voucher_template_conditionally($template, $type, $order) {
    if (!empty($_GET['voucher_pdf']) && $_GET['voucher_pdf'] == 1) {
        $voucher_template = get_stylesheet_directory() . '/woocommerce/pdf/voucher-template/' . basename($template);
        
        if (file_exists($voucher_template)) {
            return $voucher_template;
        }
    }
    return $template;
}

Any insight or example on how to do this correctly?

Extendons · Accepted Answer · 2025-11-12 12:05:01Z

First you need to register your custom PDF type with WP Overnight so it’s a valid document:

add_filter( 'wpo_wcpdf_document_types', function( $document_types ) {
    $document_types['voucher'] = array(
        'title'       => __( 'Voucher', 'your-textdomain' ),
        'description' => __( 'Custom voucher PDF without prices', 'your-textdomain' ),
        'template'    => 'voucher.php',
        'folder'      => 'woocommerce/pdf',
        'filename'    => 'voucher-{order_number}.pdf',
        'attach_to_email' => false,
        'paper_size'  => 'A4',
    );
    return $document_types;
});

Next, your button should pass the new document type:

add_action('woocommerce_thankyou', 'add_voucher_pdf_button', 20);
function add_voucher_pdf_button($order_id) {
    if (!$order_id) return;

    $order = wc_get_order($order_id);
    if (!$order) return;

    $nonce = wp_create_nonce('generate_wpo_wcpdf');

    $pdf_url = add_query_arg(array(
        'action'    => 'generate_wpo_wcpdf',
        'document'  => 'voucher',  // <-- new document type
        'order_ids' => $order->get_id(),
        '_wpnonce'  => $nonce,
    ), admin_url('admin-ajax.php'));

    echo '<a href="' . esc_url($pdf_url) . '" target="_blank" class="button alt" style="margin-top:20px;">Download Voucher PDF</a>';
}

Finally, place your template file here:

wp-content/themes/your-child-theme/woocommerce/pdf/voucher.php

Hope it works for you!

Collectives™ on Stack Overflow

“Invalid Order” error when generating second custom PDF template

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related