使用 IF .. ElseIF 等优化 Woocommerce 小片段代码

Question

请你帮我优化我写的小sn-p，在将产品添加到购物车中后应用折扣tech分配了运输类别和其他没有为WordPress（Woocommerce）网站指定类别的产品。 如何优化if .. elseif 并使其整体变得更好。另外，添加break 是一个好习惯吗？我是 PHP 新手，但我目前正在学习并希望改进我的代码。或许我可以使用类似于switch 的东西？非常感谢任何帮助和示例！

add_filter( 'woocommerce_package_rates', 'adjustment_in_rates_of_product_with_shipping_class', 12, 2 );

function adjustment_in_rates_of_product_with_shipping_class( $available_shipping_methods, $package ) {

   // Shipping class slug to be eligible for a discount when combined with no class products
    $shipping_class = array(
        'tech',
    );

   // Discount
    $discounteuro = 3.50;
    $discountgbp = 3.20;
    $discountusd = 4;
    $discountglobalusd = 5;

    // Enter the shipping method value
    $shipping_services = array(
       'flat_rate:5',
    );

    $shipping_class_exists = false;
    foreach(WC()->cart->get_cart_contents() as $key => $values) {
        if ( in_array($values['data']->get_shipping_class() , $shipping_class) ) {
            $shipping_class_exists = true;
            break;
        }
    }

    $shipping_class_no_exists = false;
    foreach(WC()->cart->get_cart_contents() as $key => $values) {
        if ( strlen($values['data']->get_shipping_class()) == 0 ) {
            $shipping_class_no_exists = true;
            break;
        }
    }

    if ($shipping_class_exists && $shipping_class_no_exists) {
        foreach ($available_shipping_methods as $key => $value) {
            if ( in_array($value->get_id() , $shipping_services) && get_woocommerce_currency() == 'EUR' ) {
                $available_shipping_methods[$key]->cost -= $discounteuro;
        break;
            }
        elseif ( in_array($value->get_id() , $shipping_services) && get_woocommerce_currency() == 'GBP' ) {
                $available_shipping_methods[$key]->cost -= $discountgbp;
        break;
        }
        elseif ( in_array($value->get_id() , $shipping_services) && get_woocommerce_currency() == 'USD' ) {
                $available_shipping_methods[$key]->cost -= $discountusd;
        break;
       }
        else {
            $available_shipping_methods[$key]->cost -= $discountglobalusd;   
        break;
       }
        }
    }

    return $available_shipping_methods;
}

Answer 1

我会将您的前两个循环合并为一个循环，因为没有理由将数据循环两次。像这样的

$shipping_class_exists = false;
$shipping_class_no_exists = false;

foreach(WC()->cart->get_cart_contents() as $key => $values) {
    if(in_array($values['data']->get_shipping_class() , $shipping_class)) {
        $shipping_class_exists = true;
    }
    if(strlen($values['data']->get_shipping_class()) == 0) {
        $shipping_class_no_exists = true;
    }
}

我还将您的折扣转换为一个数组，以便更轻松地从您的循环中调用。

$discounts = [
    'EUR' => 3.5,
    'GBP' => 3.2,
    'USD' => 4,
    'globalusd' => 5
];

那么你的循环就会变成

if ($shipping_class_exists && $shipping_class_no_exists) {
    foreach ($available_shipping_methods as $key => $value) {
        
        //store currency type in an easier to access variable
        $currency = get_woocommerce_currency();   
        
        //create variable `$discount` defaulting to `$discounts['globalusd']`
        $discount = $discounts['globalusd'];

        if(in_array($value->get_id(), $shipping_services) && array_key_exists($currency, $discounts)) {

            //if $value->get_id()` is in `$shipping_services` and `$currency` key exists in $discounts
            //then alter $discount to the correct value
            $discount = $discounts[$currency];
        }

        //subtract discount from cost        
        $available_shipping_methods[$key]->cost -= $discount;

    }
}

Answer 2

更新了 2 删除了一些错误

以下优化代码应该可以解决问题（代码已注释）：

add_filter( 'woocommerce_package_rates', 'adjustment_in_rates_of_product_with_shipping_class', 12, 2 );

function adjustment_in_rates_of_product_with_shipping_class( $rates, $package ) {

    // Shipping class slug to be eligible for a discount when combined with no class products
    $target_shipping_classes = array('tech');

    // Enter the shipping method value
    $shipping_rate_ids       = array('flat_rate:5');

    // Discount based on currency
    $currency_discounts      = array(
        ''      => 5,
        'EUR'   => 3.50,
        'GBP'   => 3.20,
        'USD'   => 4,
    );

    $shipping_class_found    = $other_shipping_classes = $currency_found = false;

    $woocommerce_currency    = get_woocommerce_currency();

    // Loop through cart items for the current package
    foreach( $package['contents'] as $item ) {
        $shipping_class = $item['data']->get_shipping_class(); // Get item shipping class

        if ( in_array( $shipping_class, $target_shipping_classes ) ) {
            $shipping_class_found = true;
        }
        elseif ( ! empty($shipping_class) ) {
            $other_shipping_classes = true;
        }
    }

    // When there is only items from the defined shipping classes
    if ( $shipping_class_found && ! $other_shipping_class ) {
        // Loop through available shipping rates in the current shipping package
        foreach ( $rates as $rate_key => $rate ) {
            if ( in_array($rate_key, $shipping_rate_ids) ) {
                // Loop through defined currency discounts
                foreach ( $currency_discounts as $currency => $discount ) {
                    if ( $woocommerce_currency === $currency ) {
                        $rates[$rate_key]->cost -= $discount;
                        $currency_found = true;
                        break;
                    }
                }
                // If no currency match, we get the default value (the first one)
                if ( ! $currency_found ) {
                    $rates[$shipping_rate_id]->cost -= reset($currency_discounts);
                }
            }
        }
    }

    return $rates;
}

代码位于活动子主题（或活动主题）的functions.php 文件中。经过测试并且可以工作。

注意：您应该在保存此代码后清空您的代码。