How to properly get current quote in Carrier Collect Rates function?

Question

I'm using Magento 2.4.1 and I want to retrieve the current quote in collectRates function in my Carrier model, but sometimes it will prompt an infinite loop error like this:

this is how i retrieve the current quote in My Carrier Model

class Standard extends \Magento\Shipping\Model\Carrier\AbstractCarrier implements
    \Magento\Shipping\Model\Carrier\CarrierInterface
{
   public function collectRates(RateRequest $request)
   { 
     $quote = $this->checkoutSession->getQuote();
     $subTotal = $quote->getData('subtotal_with_discount');
     $ddate = $quote->getShippingDeliveryDate(); // this is a custom column i made in quote table
   }
}

The reason to get quotes is that I need to retrieve the quote attribute value to do some calculation in the collect rates function

Answer 1

You can not directly get quote in collect rate.

The $this->checkoutSession->getQuote() will call your collectRates function at the end, so you will end up getting infinite loop.

the $request variable will also give you almost all the data you need, like

• $request->getAllItems()
• $request->getOrderSubtotal();
• $request->getDestCity();
• etc

So there is no direct way to get quote. This is not the end, you have an alternative, may be it will work for you. Try this code:

    /**
     * Do not use checkoutSession->getQuote()!!! it will cause infinite loop for
     * quotes with trigger_recollect = 1, see Quote::_afterLoad()
     */
    $items = $request->getAllItems();
    if (empty($items)) {
        return false;
    }

    /** @var \Magento\Quote\Model\Quote\Item $firstItem */
    $firstItem = reset($items);
    if (!$firstItem) {
        return false;
    }

    $quote = $firstItem->getQuote();
    if (!($quote instanceof \Magento\Quote\Model\Quote)) {
        return false;
    }

Hope this will help you.

Answer 2

Warning : Do not use $this->checkoutSession->getQuote(); cause it recursively calls your get collect method and you will have infinite loop.

You can also get current quote in collect rate method by load cart model, it always gives you quote of current session.

use  \Magento\Checkout\Model\Cart;

class CarrierExample extends AbstractCarrier implements CarrierInterface{
    protected $cart;

    public function __construct(
             Cart $cart
         ){
             $this->cart= $cart;
    }           
    
    public function collectRates(RateRequest $request){
        $quote = $this->cart->getQuote();
        $subTotal = $quote->getData('subtotal_with_discount');
        $ddate = $quote->getShippingDeliveryDate(); // this is a custom column i made in quote table
    }
}

Answer 3

Updated answer 2022, because the class Magento\Checkout\Model\Cart is deprecated, you have to use Magento\Quote\Model\Quote.

use Magento\Quote\Model\Quote;

use Magento\Framework\App\Config\ScopeConfigInterface;
use Magento\Quote\Model\Quote\Address\RateResult\ErrorFactory;
use Psr\Log\LoggerInterface;

class Standard extends \Magento\Shipping\Model\Carrier\AbstractCarrier implements \Magento\Shipping\Model\Carrier\CarrierInterface 
{
    /** @var Quote */
    private $quote;

    public function __construct(
        Quote $quote,
        ScopeConfigInterface $scopeConfig,
        ErrorFactory $rateErrorFactory,
        LoggerInterface $logger,
        array $data = []
    ) {
          parent::__construct($scopeConfig, $rateErrorFactory, $logger, $data);
          $this->quote = $quote;
    }

    public function collectRates(RateRequest $request)
    { 
        $subTotal = $this->quote->getData('subtotal_with_discount');
        $ddate = $this->quote->getShippingDeliveryDate();
    }
}