perf: filter in sql, not php

Previously, this code filtered the order list in PHP-land, which is computationally
infeasible once the order list size gets too large.

This reworks to filter in SQL instead, which is orders of magnitude more efficient.
Additionally, no more memory errors on large databases of orders.

Author: damienwebdev

Model/Resolver/GuestOrders.php

@@ -1,8 +1,10 @@
 <?php
+
 /**
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+
 declare(strict_types=1);
 
 namespace Graycore\GuestOrdersGraphQl\Model\Resolver;
@@ -82,39 +84,37 @@ public function resolve(
         array $args = null
     ) {
         return [
-            'items' => $this->formatOrdersArray($this->getOrdersForCart($args['cartId']))
+            'items' => $this->formatOrder($this->getOrderForCart($args['cartId']))
         ];
     }
 
     /**
      * Format order models for graphql schema.
      * Copied from the Magento resolver.
      *
-     * @param OrderInterface[] $orderModels
+     * @param \Magento\Sales\Model\Order $order
      * @return array
      */
-    private function formatOrdersArray(array $orderModels)
+    private function formatOrder(\Magento\Sales\Model\Order $order)
     {
-        $ordersArray = [];
-        foreach ($orderModels as $orderModel) {
-            $ordersArray[] = [
-                'created_at' => $orderModel->getCreatedAt(),
-                'grand_total' => $orderModel->getGrandTotal(),
-                'id' => base64_encode($orderModel->getEntityId()),
-                'increment_id' => $orderModel->getIncrementId(),
-                'number' => $orderModel->getIncrementId(),
-                'order_date' => $orderModel->getCreatedAt(),
-                'order_number' => $orderModel->getIncrementId(),
-                'status' => $orderModel->getStatusLabel(),
-                'shipping_method' => $orderModel->getShippingDescription(),
-                'shipping_address' => $this->orderAddress->getOrderShippingAddress($orderModel),
-                'billing_address' => $this->orderAddress->getOrderBillingAddress($orderModel),
-                'payment_methods' => $this->orderPayments->getOrderPaymentMethod($orderModel),
-                'model' => $orderModel,
-                'email' => $orderModel->getCustomerEmail()
-            ];
-        }
-        return $ordersArray;
+        return [
+            [
+                'created_at' => $order->getCreatedAt(),
+                'grand_total' => $order->getGrandTotal(),
+                'id' => base64_encode($order->getEntityId() ?? ''),
+                'increment_id' => $order->getIncrementId(),
+                'number' => $order->getIncrementId(),
+                'order_date' => $order->getCreatedAt(),
+                'order_number' => $order->getIncrementId(),
+                'status' => $order->getStatusLabel(),
+                'shipping_method' => $order->getShippingDescription(),
+                'shipping_address' => $this->orderAddress->getOrderShippingAddress($order),
+                'billing_address' => $this->orderAddress->getOrderBillingAddress($order),
+                'payment_methods' => $this->orderPayments->getOrderPaymentMethod($order),
+                'model' => $order,
+                'email' => $order->getCustomerEmail()
+            ]
+        ];
     }
 
     /**
@@ -137,10 +137,8 @@ private function getCart(string $cartHash)
             );
         }
 
-        $cartCustomerId = (int)$cart->getCustomerId();
-
         /* Not a guest cart, throw */
-        if (0 !== $cartCustomerId) {
+        if (!$cart->getCustomerIsGuest()) {
             throw new GraphQlAuthorizationException(
                 __(
                     'The cart "%masked_cart_id" is not a guest cart',
@@ -158,7 +156,7 @@ private function getCart(string $cartHash)
      * @param string $cartHash the hashed cart ID
      * @throws GraphQlNoSuchEntityException
      */
-    private function getOrdersForCart(string $cartHash)
+    private function getOrderForCart(string $cartHash)
     {
         $orderId = $this->getCart($cartHash)->getReservedOrderId();
 
@@ -171,13 +169,18 @@ private function getOrdersForCart(string $cartHash)
             );
         }
 
-        $orders = $this->collectionFactory->create(null)->getItems();
 
-        /** @param OrderInterface $order */
-        $isCartOrder = function ($order) use ($orderId) {
-            return $order->getIncrementId() === $orderId;
-        };
 
-        return array_values(array_filter($orders, $isCartOrder));
+        $order = $this->collectionFactory->create()->addFieldToSearchFilter('increment_id', $orderId)->getFirstItem();
+
+        if (!$order->getIncrementId()) {
+            throw new GraphQlNoSuchEntityException(
+                __(
+                    'Could not find an order associated with cart with ID "%masked_cart_id"',
+                    ['masked_cart_id' => $cartHash]
+                )
+            );
+        }
+        return $order;
     }
 }