WooCommerce：如果购物车中只有特定产品，请清除购物车

如果用户在我的网站上购买产品，我允许他们在结账时将折扣产品添加到购物车中。但是，用户可以从购物车中删除原始产品，折扣产品仍保留在购物车中。

是否有可能，如果打折产品是购物车中唯一的产品，那么购物车应该是空的？我还没有找到这样做的方法。

我尝试的内容

目前，我使用Github上的bekarice中的the following code：

/**
 * Renders a notice and prevents checkout if the cart
 * only contains products in a specific category
 */
function sv_wc_prevent_checkout_for_category() {
    
    // set the slug of the category for which we disallow checkout
    $category = 'clothing';
    
    // get the product category
    $product_cat = get_term_by( 'slug', $category, 'product_cat' );
    
    // sanity check to prevent fatals if the term doesn't exist
    if ( is_wp_error( $product_cat ) ) {
        return;
    }
    
    $category_name = '<a href="' . get_term_link( $category, 'product_cat' ) . '">' . $product_cat->name . '</a>';
    
    // check if this category is the only thing in the cart
    if ( sv_wc_is_category_alone_in_cart( $category ) ) {
        
        // render a notice to explain why checkout is blocked
        wc_add_notice( sprintf( 'Hi there! Looks like your cart only contains products from the %1$s category &ndash; you must purchase a product from another category to check out.', $category_name ), 'error' );
    }
}
add_action( 'woocommerce_check_cart_items', 'sv_wc_prevent_checkout_for_category' );


/**
 * Checks if a cart contains exclusively products in a given category
 * 
 * @param string $category the slug of the product category
 * @return bool - true if the cart only contains the given category
 */
function sv_wc_is_category_alone_in_cart( $category ) {
        
    // check each cart item for our category
    foreach ( WC()->cart->get_cart() as $cart_item_key => $cart_item ) {
        
        // if a product is not in our category, bail out since we know the category is not alone
        if ( ! has_term( $category, 'product_cat', $cart_item['data']->id ) ) {
            return false;
        }
    }
        
    // if we're here, all items in the cart are in our category
    return true;
}

但我认为这不是一个好方法。基本上，如果购物车只包含某个类别的商品，则不允许用户结账。

---

解决方案

您可以使用以下代码来检查是否将您的特定折扣产品添加到购物车中，该购物车不是空的，并且它不是一个人在购物车中，并将其从购物车中删除：

// Add to cart validation for the discounted product
add_filter( 'woocommerce_add_to_cart_validation', 'check_specific_discounted_product', 10, 3 );
function check_specific_discounted_product( $passed, $product_id, $quantity ) {
    // Settings
    $discounted_product_id = 53;

    if( WC()->cart->is_empty() && $discounted_product_id == $product_id ) {
        wc_add_notice( __("This product can't be purchased alone."), 'notice' );
        return false;
    }

    return $passed;
}

// Removing the discounted product if it's alone in cart
add_action( 'woocommerce_before_calculate_totals', 'conditionally_remove_a_discounted_product' );
function conditionally_remove_a_discounted_product( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    // Settings
    $discounted_product_id = 53;

    // Initializing variables
    $discounted_item_key = false;

    // Loop through cart items (first loop)
    foreach ( $cart->get_cart() as $cart_item_key => $cart_item ){
        // When free productis is cart
        if ( in_array( $discounted_product_id, array($cart_item['product_id'], $cart_item['variation_id']) ) ) {
            $discounted_item_key = $cart_item_key;
        }
        // if any other product is in cart: EXIT
        else {
           return;
        }
    }
    // When the discounted product is alone in cart, remove it
    if( $discounted_item_key ) {
        // display notice on removal (optional)
        wc_clear_notices();
        wc_add_notice( __("The discounted product can't be purchased alone and has been removed."), 'notice' );

        $cart->remove_cart_item( $discounted_item_key ); // Remove
    }
}

代码放在活动子主题(或活动主题)的函数.php文件中。已测试并正常工作。