检查变量是否是 WooCommerce 中 Class 对象的实例

Question

我是运行一个功能，我通过该功能检查用户是否对他们之前的订单进行了退款 item/s，如果他们这样做，则在结帐时将信用额度用作负购物车费用。该功能适用于之前下过订单的用户，但在网站上对新用户造成严重错误。

Fatal error: Uncaught Error: Call to a member function get_refunds() on bool in /wp-content/themes/my-theme/refunds.php:20 Stack trace:  
#0 /wp-includes/class-wp-hook.php(287): add_last_order_refund_total_at_checkout(Object(WC_Cart))  
#1 /wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters('', Array)  
#2 /wp-includes/plugin.php(478): WP_Hook->do_action(Array)  
#3 /wp-content/plugins/woocommerce/includes/class-wc-cart.php(1714): do_action('woocommerce_car...', Object(WC_Cart))  
#4 /wp-content/plugins/woocommerce/includes/class-wc-cart-totals.php(270): WC_Cart->calculate_fees()  
#5 /wp-content/plugins/woocommerce/includes/class-wc-cart-totals.php(829): WC_Cart_Totals->get_fees_from_cart()  
#6 /wp-content/plugins/woocommerce/includes/class-wc- in /wp-content/themes/my-theme/refunds.php on line 20

这是检查之前订单是否有任何退款的代码：

//Check total of refunded items from last order - add as a fee at checkout
function add_last_order_refund_total_at_checkout($cart_object){
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    $user_id = get_current_user_id(); // The current user ID
    $customer = new WC_Customer( $user_id );
    $last_order = $customer->get_last_order();
    $order_id = $last_order;

    // Get the WC_Order Object instance (from the order ID)
    $order = wc_get_order( $order_id );

    // Get the Order refunds (array of refunds)
    $order_refunds = $order->get_refunds();
    $total_to_refund = $order->get_total_refunded()*(-1);//WIP need to check which items have tax
    
    if (!empty($order_refunds)) WC()->cart->add_fee( 'Refund', $total_to_refund  );  
}
add_action( 'woocommerce_cart_calculate_fees', 'add_last_order_refund_total_at_checkout', 10, 1 );

我认为我需要首先检查用户是否有任何先前的订单，否则 get_refund() 会导致错误，因为他们没有任何订单需要检查？我将如何安全地执行此操作？

Answer 1

试一试，添加了多个控件，看评论

// Check total of refunded items from last order - add as a fee at checkout
function add_last_order_refund_total_at_checkout( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    // The current user ID
    $user_id = get_current_user_id();
    
    // User id exists
    if ( $user_id > 0 ) {
        $customer = new WC_Customer( $user_id );
        
        // Get last order
        $last_order = $customer->get_last_order();

        // True
        if ( $last_order ) {

            // Get the order id
            $order_id = $last_order->get_id();
        
            // Order ID exists
            if ( is_numeric( $order_id ) ) {
                // Get the WC_Order Object instance (from the order ID)
                $order = wc_get_order( $order_id );

                // Get the Order refunds (array of refunds)
                $order_refunds = $order->get_refunds();
            
                // NOT empty
                if ( ! empty( $order_refunds) ) {
                    // WIP need to check which items have tax
                    $total_to_refund = $order->get_total_refunded();
                
                    // Add fee
                    $cart->add_fee( 'Refund', $total_to_refund  );
                }
            }
        }
    }
}
add_action( 'woocommerce_cart_calculate_fees', 'add_last_order_refund_total_at_checkout', 10, 1 );

Answer 2

如果您查看 WC_Customer get_last_order() 方法 documentation or source code，您将看到：

/*
 * @return WC_Order|false
 */

这意味着 get_last_order() 方法可以 return 或者 :

WC_Order 对象
或false布尔值。

所以你可以在你的代码中使用：

$last_order = $customer->get_last_order();

if ( ! $last_order )  {
   return; // Exit (Not an order)
}

为了避免这个错误。

现在您可以使用 is_a() php 条件函数来检查变量是否来自特定对象 class 而不是其他对象，例如：

$last_order = $customer->get_last_order();

if ( ! is_a( $last_order, 'WC_Order' ) ) {
   return; // Exit (Not an order)
}

// Your other code…

或者您可以使用 method_exists() php 条件函数 WC_Order get_refunds() 方法，检查变量是否来自特定对象 class 而不是别的：

$last_order = $customer->get_last_order();

if ( ! method_exists( $last_order, 'get_refunds' ) )  {
   return; // Exit (Not an order)
}

// Your other code…

三种情况都很好，避免了错误

检查变量是否是 WooCommerce 中 Class 对象的实例

Check that a variable is an instance of a Class Object in WooCommerce

php

instance-variables

orders

woocommerce

object-class