Snippet to automatically mark WooCommerce orders containing only virtual products as completed

autocomplete-virtual-orders.php

<?php

add_action('woocommerce_order_status_changed', 'auto_complete_virtual_orders');
function auto_complete_virtual_orders($order_id) {
    if ( ! $order_id ) {
    	return;
    }
	
    $order = wc_get_order( $order_id );
    if ($order->data['status'] == 'processing') {
        $virtual_order = null;
        if ( count( $order->get_items() ) > 0 ) {
            foreach( $order->get_items() as $item ) {
                if ( 'line_item' == $item['type'] ) {
                    $_product = $order->get_product_from_item( $item );
                    if ( ! $_product->is_virtual() ) {
                        // once we find one non-virtual product, break out of the loop
                        $virtual_order = false;
                        break;
                    } else {
                        $virtual_order = true;
                    }
                }
            }
        }
        // if all are virtual products, mark as completed
        if ( $virtual_order ) {
            $order->update_status( 'completed' );
        }
    }
}

?>