从观察者处更改运费

Question

我有套餐运费方式，运费价格设置为5英镑，当小计超过35英镑（导入csv文件）时，也设置免运费。此外，商店还有额外的货币（EUR）。我必须将观察员的运费价格改为6欧元（即4.xx英镑）和免费运送小计到40欧元（将以磅计算）。这种行为背后的逻辑是创建的，但问题是我无法更改运费。

注意：我在SE和Magento论坛上发现了许多类似的问题，但没有一个解决方案适合我。

使用的事件是sales_quote_collect_totals_before。

以下是观察者的方法：

public function salesQuoteCollectTotalsBefore(Varien_Event_Observer $observer)
    {
        try {
        $quote = $observer->getQuote();
        $store = Mage::app()->getStore($quote->getStoreId());
        $address = $quote->getShippingAddress();

        if($address->getCountry() == 'IE') {
            $currencyRates = Mage::getModel('directory/currency')
                ->getCurrencyRates(Mage::app()->getBaseCurrencyCode(), array_values(Mage::getModel('directory/currency')
                    ->getConfigAllowCurrencies()));

            $shippingCostInEur = 6;
            $freeShippingSubtotalInEur = 40;
            $isFreeShipping = false;
            $isDifferentCost = false;
            $newCost = 0;

            if(Mage::app()->getStore()->getCurrentCurrencyCode() == 'EUR') {
                $subtotal = $quote->getSubtotal();

                if($subtotal >= $freeShippingSubtotalInEur) {
                    $isFreeShipping = true;
                } else {
                    $isDifferentCost = true;
                    $newCost = $shippingCostInEur;
                }
            } else {
                $baseSubtotal = $quote->getBaseSubtotal();
                $subtotalInEur = $baseSubtotal*$currencyRates['EUR'];

                if($subtotalInEur >= $freeShippingSubtotalInEur) {
                    $isFreeShipping = true;
                } else {
                    $isDifferentCost = true;
                    $newCost = $shippingCostInEur/$currencyRates['EUR'];
                }
            }

            if($isFreeShipping) {
                //$address->setFreeShipping(true);
                $address->setShippingMethod('freeshipping_freeshipping');
                //$carrierCode = 'tablerate';
                //$store->setConfig("carriers/{$carrierCode}/handling_fee", 0);
            }

            if($isDifferentCost) {
                $address->setShippingAmount($newCost);
                //$store->setConfig("carriers/{$carrierCode}/handling_fee", $newCost);
            }

            if($isDifferentCost || $isFreeShipping) {
                $quote->setTotalsCollectedFlag(true)
                      ->collectTotals();
                      //->save();
            }
        }

        } catch(Exception $e) {
            Mage::log('BOOM: '.$e->getMessage(), null, 'test.log', true);
        }

        return $this;
    }

有什么想法吗？我也尝试了this免费送货，它有效，但我不确定重写核心方法是否是个好主意。即使我使用它免费送货，当然还存在另一个运费的问题。

将Magento 1.9.0.1与Onepage结帐使用。

编辑：通过以下示例，一切似乎都有效，但我不确定这是否是一个好方法。据我所知，我只是更改了耦合XML中保存的配置值。不确定它是否足够节省。另外，我只更改handling_fee而不是价格。这是：

public function salesQuoteCollectTotalsBefore(Varien_Event_Observer $observer)
{
    $quote = $observer->getQuote();
    $address = $quote->getShippingAddress();
    $store = Mage::app()->getStore($quote->getStoreId());

    if($address->getCountry() == 'IE') {
        $currencyRates = Mage::getModel('directory/currency')
            ->getCurrencyRates(Mage::app()->getBaseCurrencyCode(), array_values(Mage::getModel('directory/currency')
                ->getConfigAllowCurrencies()));

        $shippingCostInEur = (float)$store->getConfig('carriers/eservice_shippingrates/fixed_shipping_price');
        $freeShippingSubtotalInEur = (float)$store->getConfig('carriers/eservice_shippingrates/free_shipping_min_subtotal');
        $newCost = $shippingCostInEur/$currencyRates['EUR'];

        if(Mage::app()->getStore()->getCurrentCurrencyCode() == 'EUR') {
            $subtotalInEur = $quote->getSubtotal();
        } else {
            $baseSubtotal = $quote->getBaseSubtotal();
            $subtotalInEur = $baseSubtotal*$currencyRates['EUR'];
        }

        if($subtotalInEur >= $freeShippingSubtotalInEur) {
            $store->setConfig('carriers/tablerate/name', 'Free');
            $newCost = 0;
        } else {
            $store->setConfig('carriers/tablerate/name', $store->getConfig('carriers/eservice_shippingrates/method_name'));
        }

        $store->setConfig('carriers/tablerate/title', $store->getConfig('carriers/eservice_shippingrates/title'));
        $store->setConfig("carriers/tablerate/handling_fee", $newCost);
    }

    return $this;
}