php - Uncaught Error : Call to a member function generate_cart_id() on null

Question

我有以下代码在将产品添加到购物车而不是重定向到购物车页面时重定向到 WooCommerce 结帐页面。它工作得很好。

// Immediately go to checkout when adding to cart.
add_filter( 'woocommerce_add_to_cart_redirect', function( $url ) {
    return wc_get_checkout_url();
});

add_filter( 'woocommerce_product_add_to_cart_url', 'custom_fix_for_individual_products', 10, 2 );
function custom_fix_for_individual_products( $add_to_cart_url, $product ){
    $product_cart_id = WC()->cart->generate_cart_id( $product->get_id() );
    if( 
        $product->get_sold_individually() // if individual product
        && !is_null($product_cart_id) // Added to try and understand the error I'm getting
        // The next line causes a server error, but only in the edit view of the Homepage after clicking on "Update".
        && WC()->cart->find_product_in_cart( $product_cart_id ) // if already in the cart.
        && $product->is_purchasable()
    ) {
        $add_to_cart_url = wc_get_checkout_url(); // Instead of adding it to cart, go to checkout.
    }

    return $add_to_cart_url;
}

但是在后端，当我编辑主页并单击更新时，我收到一个指向第二个功能代码的服务器错误。
这是我在服务器日志上得到的:

PHP Fatal error:  Uncaught Error: Call to a member function generate_cart_id() on null in /home/xxx/public_html/wp-content/plugins/code-snippets/php/snippet-ops.php(446) : eval()'d code:11
Stack trace:
#0 /home/xxx/public_html/wp-includes/class-wp-hook.php(287): misha_fix_for_individual_products()
#1 /home/xxx/public_html/wp-includes/plugin.php(212): WP_Hook->apply_filters()
#2 /home/xxx/public_html/wp-content/plugins/learndash-woocommerce/learndash_woocommerce.php(1285): apply_filters()
#3 /home/xxx/public_html/wp-content/plugins/woocommerce/includes/class-wc-shortcodes.php(398): WC_Product_Course->add_to_cart_url()
#4 /home/xxx/public_html/wp-includes/shortcodes.php(343): WC_Shortcodes::product_add_to_cart_url()
#5 [internal function]: do_shortcode_tag()
#6 /home/xxx/public_html/wp-includes/shortcodes.php in /home/xxx/public_html/wp-content/plugins/code-snippets/php/snippet-ops.php(446) : eval()'d code on line 11

知道如何解决这个问题吗？

Answer 1

您可以使用以下内容来避免后端产生的错误:

add_filter( 'woocommerce_add_to_cart_redirect', 'wc_get_checkout_url' );

add_filter( 'woocommerce_product_add_to_cart_url', 'custom_fix_for_individual_products', 10, 2 );
function custom_fix_for_individual_products( $add_to_cart_url, $product ){
    if( is_admin() || current_user_can('edit_pages') ) {
        return $add_to_cart_url; // Exit if it's on admin
    }
    
    $cart_id = WC()->cart->generate_cart_id( $product->get_id() );
    
    if( $product->get_sold_individually() && $product->is_purchasable() 
    && WC()->cart->find_product_in_cart( $cart_id ) ) {
        $add_to_cart_url = wc_get_checkout_url(); 
    }

    return $add_to_cart_url;
}

代码位于事件子主题(或事件主题)的 functions.php 文件中。它应该解决错误。