我对WooCommerce一无所知，但从他们的Action and Filter Reference, 我可以看到*shipping*.

其中大多数似乎位于名为form-shipping.php:

模板挂钩：操作woocommerce_before_checkout_shipping_form

woocommerce_after_checkout_shipping_form

woocommerce_before_shipping_calculator

woocommerce_after_shipping_calculator

woocommerce_cart_totals_after_shipping

woocommerce_checkout_shipping

woocommerce_review_order_before_shipping

woocommerce_review_order_after_shippingwoocommerce_cart_shipping_method_full_label

woocommerce_shiptobilling_default

woocommerce_shipping_calculator_enable_city

woocommerce_shipping_calculator_enable_postcodewoocommerce_calculated_shipping

woocommerce_load_shipping_methods

woocommerce_shipping_init

woocommerce_shipping_method_chosenwoocommerce_available_shipping_methods

woocommerce_cart_needs_shipping

woocommerce_cart_ready_to_calc_shipping

woocommerce_cart_shipping_packages

woocommerce_countries_shipping_to_prefix

woocommerce_order_amount_shipping

woocommerce_order_amount_shipping_tax

woocommerce_order_shipping_method

woocommerce_order_shipping_to_display

woocommerce_shipping_.$this->id._is_available

woocommerce_shipping_calculator_enable_city

woocommerce_shipping_calculator_enable_postcode

woocommerce_shipping_chosen_method

woocommerce_shipping_fields

woocommerce_shipping_method_supports

woocommerce_shipping_method_title

woocommerce_shipping_methods

无论如何，在找到正确的过滤器之前，您必须为所有过滤器编写大量的测试回调。WooCommerce文档似乎除了这个无休止的文件名列表（没有文件夹）之外什么都没有。因此，如果你或其他人想处理这件事，祝你好运。

您可以使用woocommerce_available_shipping_methods 筛选以执行此操作。注意：如果你有基于角色的发货插件，你可能会发现它在某些情况下会删除免费发货选项；如果购物者有免费送货的优惠券，此代码会将其放回原处。

/**
* if Free Shipping method is available, reduce to just Free Shipping
* @param array $available_methods
* @return array
*/
add_filter(\'woocommerce_available_shipping_methods\', function($available_methods) {
    global $woocommerce;

    // check for coupon with Free Shipping
    if (wpse_114581_has_coupon_free_shipping()) {
        // ensure that Free Shipping is in the list of available methods (again -- Role Based Methods may strip Free Shipping for Guests)
        if (!isset($available_methods[\'free_shipping\'])) {
            $available_methods[\'free_shipping\'] = new WC_Shipping_Rate(\'free_shipping\', \'Free Shipping\', 0, array(), \'\');
        }
    }

    // if both Free Shipping and another method, reduce to just free shipping
    if (isset($available_methods[\'free_shipping\']) && count($available_methods) > 1) {
        $available_methods = array(\'free_shipping\' => $available_methods[\'free_shipping\']);

        // change title on Free Shipping method
        $available_methods[\'free_shipping\']->method_title = \'flat rate shipping (free!)\';
    }

    return $available_methods;
});

/**
* check for coupon with free shipping
* @return bool
*/
function wpse_114581_has_coupon_free_shipping() {
    global $woocommerce;

    foreach ($woocommerce->cart->applied_coupons as $code) {
        $coupon = new WC_Coupon($code);
        if ($coupon->is_valid() === true) {
            if ($coupon->enable_free_shipping()) {
                return true;
            }
        }
    }

    return false;
}