checkGuestAuth example

// Handle guest authentication if deeplink is set         if (!$context->getCustomer() && $deepLinkFilter instanceof EqualsFilter) {
            try {
                $cacheKey = strtolower((string) $deepLinkFilter->getValue()) . '-' . $request->getClientIp();

                $this->rateLimiter->ensureAccepted(RateLimiter::GUEST_LOGIN, $cacheKey);
            } catch (RateLimitExceededException $exception) {
                throw OrderException::customerAuthThrottledException($exception->getWaitTime(), $exception);
            }

            $order = $orders->first();
            $this->checkGuestAuth($order, $request);
        }

        if (isset($cacheKey)) {
            $this->rateLimiter->reset(RateLimiter::GUEST_LOGIN, $cacheKey);
        }

        $response = new OrderRouteResponse($orderResult);
        if ($request->get('checkPromotion') === true) {
            foreach ($orders as $order) {
                $promotions = $this->getActivePromotions($order, $context);
                $changeable = true;