Php 用于计算付款费用的WooCommerce管理编辑产品中的自定义复选框

按照对上一个问题的Exclude some products from calculated additional fee in WooCommerce回答，我对前面代码中的数组进行了一些更改.
然后，我在产品编辑页面中添加了一个复选框:如果它处于活动状态(选中)，则不会为该产品计税.如果该选项处于非活动状态(默认情况下未选中)，则将计算该税.

1. Modify the Function to Include an Excluded Array:个

// +9% tax add-fee on paypal
add_action( 'woocommerce_cart_calculate_fees', 'add_checkout_fee_for_gateway', 10, 1 );
function add_checkout_fee_for_gateway( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) ) 
        return;

    // Retrieve excluded product IDs from post meta
    $excluded_product_ids = get_option('excluded_product_ids', array());
    
    // Only on checkout page and for specific payment method ID
    if ( is_checkout() && ! is_wc_endpoint_url() 
    && WC()->session->get('chosen_payment_method') === 'paypal' ) {
        $percentage_rate      = 0.09; // Defined percentage rate
        $custom_subtotal      = 0; // Initializing
        
        // Loop through cart items
        foreach( $cart->get_cart() as $item ) {
            // Calculate items subtotal from non excluded products
            if( ! in_array($item['product_id'], $excluded_product_ids) ) {
                $custom_subtotal += (float) $item['line_subtotal'];
            }
        }

        if ( $custom_subtotal > 0 ) {
            $cart->add_fee( __('9% value added tax'), ($custom_subtotal * $percentage_rate), true, '' );
        }
    }
}

2. Add Checkbox to Product Edit Page:个

// Add checkbox to product edit page
add_action('woocommerce_product_options_general_product_data', 'add_custom_product_field');
function add_custom_product_field() {
    global $post;

    // Checkbox field
    woocommerce_wp_checkbox(
        array(
            'id'            => 'exclude_from_tax',
            'wrapper_class' => 'show_if_simple',
            'label'         => __('Exclude from Tax Calculation'),
            'description'   => __('Check this box to exclude this product from tax calculation.'),
            'value'         => get_post_meta($post->ID, 'exclude_from_tax', true) ? 'yes' : 'no',
        )
    );
}

// Save checkbox value
add_action('woocommerce_process_product_meta', 'save_custom_product_field');
function save_custom_product_field($post_id) {
    // Checkbox field
    $checkbox = isset($_POST['exclude_from_tax']) ? 'yes' : 'no';
    update_post_meta($post_id, 'exclude_from_tax', $checkbox);
}

OR this: (combined version! (maybe better all in one))个

add_action('woocommerce_cart_calculate_fees', 'add_checkout_fee_and_product_field', 10, 1);
function add_checkout_fee_and_product_field($cart) {
    if (is_admin() && !defined('DOING_AJAX'))
        return;

    // Retrieve excluded product IDs from post meta
    $excluded_product_ids = get_option('excluded_product_ids', array());

    // Add checkbox to product edit page
    add_action('woocommerce_product_options_general_product_data', 'add_custom_product_field');
    function add_custom_product_field() {
        global $post;

        // Checkbox field
        woocommerce_wp_checkbox(
            array(
                'id' => 'exclude_from_tax',
                'wrapper_class' => 'show_if_simple',
                'label' => __('Exclude from Tax Calculation'),
                'description' => __('Check this box to exclude this product from tax calculation.'),
                'value' => get_post_meta($post->ID, 'exclude_from_tax', true) ? 'yes' : 'no',
            )
        );
    }

    // Save checkbox value
    add_action('woocommerce_process_product_meta', 'save_custom_product_field');
    function save_custom_product_field($post_id) {
        // Checkbox field
        $checkbox = isset($_POST['exclude_from_tax']) ? 'yes' : 'no';
        update_post_meta($post_id, 'exclude_from_tax', $checkbox);
    }

    // Only on checkout page and for specific payment method ID
    if (is_checkout() && !is_wc_endpoint_url() && WC()->session->get('chosen_payment_method') === 'paypal') {
        $percentage_rate = 0.09; // Defined percentage rate
        $custom_subtotal = 0; // Initializing

        // Loop through cart items
        foreach ($cart->get_cart() as $item) {
            // Calculate items subtotal from non excluded products
            if (!in_array($item['product_id'], $excluded_product_ids)) {
                $custom_subtotal += (float)$item['line_subtotal'];
            }
        }

        if ($custom_subtotal > 0) {
            $cart->add_fee(__('9% value added tax'), ($custom_subtotal * $percentage_rate), true, '');
        }
    }
}

现在我不知道我的方法和代码是否正确？是否与插件、主题或WordPress和WooCommerce的核心不兼容？或者它将不会在新的和future 的版本中创建？它不会损坏数据库吗？有没有可能用更干净、更少的代码，以更好、更安全、更容易的方式完成这项工作？