[Cart Operations] Update Cart Items Mutation

app/code/Magento/QuoteGraphQl/Model/Resolver/ApplyCouponToCart.php

@@ -50,12 +50,12 @@ public function __construct(
      */
     public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)
     {
-        if (!isset($args['input']['cart_id'])) {
+        if (!isset($args['input']['cart_id']) || empty($args['input']['cart_id'])) {
             throw new GraphQlInputException(__('Required parameter "cart_id" is missing'));
         }
         $maskedCartId = $args['input']['cart_id'];
 
-        if (!isset($args['input']['coupon_code'])) {
+        if (!isset($args['input']['coupon_code']) || empty($args['input']['coupon_code'])) {
             throw new GraphQlInputException(__('Required parameter "coupon_code" is missing'));
         }
         $couponCode = $args['input']['coupon_code'];

app/code/Magento/QuoteGraphQl/Model/Resolver/Cart.php

@@ -37,7 +37,7 @@ public function __construct(
      */
     public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)
     {
-        if (!isset($args['cart_id'])) {
+        if (!isset($args['cart_id']) || empty($args['cart_id'])) {
             throw new GraphQlInputException(__('Required parameter "cart_id" is missing'));
         }
         $maskedCartId = $args['cart_id'];

app/code/Magento/QuoteGraphQl/Model/Resolver/RemoveCouponFromCart.php

@@ -50,7 +50,7 @@ public function __construct(
      */
     public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)
     {
-        if (!isset($args['input']['cart_id'])) {
+        if (!isset($args['input']['cart_id']) || empty($args['input']['cart_id'])) {
             throw new GraphQlInputException(__('Required parameter "cart_id" is missing'));
         }
         $maskedCartId = $args['input']['cart_id'];

app/code/Magento/QuoteGraphQl/Model/Resolver/RemoveItemFromCart.php

@@ -14,7 +14,7 @@
 use Magento\Framework\GraphQl\Exception\GraphQlNoSuchEntityException;
 use Magento\Framework\GraphQl\Query\ResolverInterface;
 use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
-use Magento\Quote\Api\GuestCartItemRepositoryInterface;
+use Magento\Quote\Api\CartItemRepositoryInterface;
 use Magento\QuoteGraphQl\Model\Cart\GetCartForUser;
 
 /**
@@ -23,46 +23,46 @@
 class RemoveItemFromCart implements ResolverInterface
 {
     /**
-     * @var GuestCartItemRepositoryInterface
+     * @var GetCartForUser
      */
-    private $guestCartItemRepository;
+    private $getCartForUser;
 
     /**
-     * @var GetCartForUser
+     * @var CartItemRepositoryInterface
      */
-    private $getCartForUser;
+    private $cartItemRepository;
 
     /**
-     * @param GuestCartItemRepositoryInterface $guestCartItemRepository
      * @param GetCartForUser $getCartForUser
+     * @param CartItemRepositoryInterface $cartItemRepository
      */
     public function __construct(
-        GuestCartItemRepositoryInterface $guestCartItemRepository,
-        GetCartForUser $getCartForUser
+        GetCartForUser $getCartForUser,
+        CartItemRepositoryInterface $cartItemRepository
     ) {
-        $this->guestCartItemRepository = $guestCartItemRepository;
         $this->getCartForUser = $getCartForUser;
+        $this->cartItemRepository = $cartItemRepository;
     }
 
     /**
      * @inheritdoc
      */
     public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)
     {
-        if (!isset($args['input']['cart_id'])) {
-            throw new GraphQlInputException(__('Required parameter "cart_id" is missing'));
+        if (!isset($args['input']['cart_id']) || empty($args['input']['cart_id'])) {
+            throw new GraphQlInputException(__('Required parameter "cart_id" is missing.'));
         }
         $maskedCartId = $args['input']['cart_id'];
 
-        if (!isset($args['input']['cart_item_id'])) {
-            throw new GraphQlInputException(__('Required parameter "cart_item_id" is missing'));
+        if (!isset($args['input']['cart_item_id']) || empty($args['input']['cart_item_id'])) {
+            throw new GraphQlInputException(__('Required parameter "cart_item_id" is missing.'));
         }
         $itemId = $args['input']['cart_item_id'];
 
         $cart = $this->getCartForUser->execute($maskedCartId, $context->getUserId());
 
         try {
-            $this->guestCartItemRepository->deleteById($maskedCartId, $itemId);
+            $this->cartItemRepository->deleteById((int)$cart->getId(), $itemId);
         } catch (NoSuchEntityException $e) {
             throw new GraphQlNoSuchEntityException(__($e->getMessage()));
         } catch (LocalizedException $e) {

app/code/Magento/QuoteGraphQl/Model/Resolver/UpdateCartItems.php

@@ -0,0 +1,118 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\QuoteGraphQl\Model\Resolver;
+
+use Magento\Framework\Exception\LocalizedException;
+use Magento\Framework\Exception\NoSuchEntityException;
+use Magento\Framework\GraphQl\Config\Element\Field;
+use Magento\Framework\GraphQl\Exception\GraphQlInputException;
+use Magento\Framework\GraphQl\Exception\GraphQlNoSuchEntityException;
+use Magento\Framework\GraphQl\Query\ResolverInterface;
+use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
+use Magento\Quote\Api\CartItemRepositoryInterface;
+use Magento\Quote\Model\Quote;
+use Magento\QuoteGraphQl\Model\Cart\GetCartForUser;
+
+/**
+ * @inheritdoc
+ */
+class UpdateCartItems implements ResolverInterface
+{
+    /**
+     * @var GetCartForUser
+     */
+    private $getCartForUser;
+
+    /**
+     * @var CartItemRepositoryInterface
+     */
+    private $cartItemRepository;
+
+    /**
+     * @param GetCartForUser $getCartForUser
+     * @param CartItemRepositoryInterface $cartItemRepository
+     */
+    public function __construct(
+        GetCartForUser $getCartForUser,
+        CartItemRepositoryInterface $cartItemRepository
+    ) {
+        $this->getCartForUser = $getCartForUser;
+        $this->cartItemRepository = $cartItemRepository;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)
+    {
+        if (!isset($args['input']['cart_id']) || empty($args['input']['cart_id'])) {
+            throw new GraphQlInputException(__('Required parameter "cart_id" is missing.'));
+        }
+        $maskedCartId = $args['input']['cart_id'];
+
+        if (!isset($args['input']['cart_items']) || empty($args['input']['cart_items'])
+            || !is_array($args['input']['cart_items'])
+        ) {
+            throw new GraphQlInputException(__('Required parameter "cart_items" is missing.'));
+        }
+        $cartItems = $args['input']['cart_items'];
+
+        $cart = $this->getCartForUser->execute($maskedCartId, $context->getUserId());
+
+        try {
+            $this->processCartItems($cart, $cartItems);
+        } catch (NoSuchEntityException $e) {
+            throw new GraphQlNoSuchEntityException(__($e->getMessage()), $e);
+        } catch (LocalizedException $e) {
+            throw new GraphQlInputException(__($e->getMessage()), $e);
+        }
+
+        return [
+            'cart' => [
+                'model' => $cart,
+            ],
+        ];
+    }
+
+    /**
+     * Process cart items
+     *
+     * @param Quote $cart
+     * @param array $items
+     * @throws GraphQlInputException
+     * @throws LocalizedException
+     */
+    private function processCartItems(Quote $cart, array $items): void
+    {
+        foreach ($items as $item) {
+            if (!isset($item['cart_item_id']) || empty($item['cart_item_id'])) {
+                throw new GraphQlInputException(__('Required parameter "cart_item_id" for "cart_items" is missing.'));
+            }
+            $itemId = $item['cart_item_id'];
+
+            if (!isset($item['quantity'])) {
+                throw new GraphQlInputException(__('Required parameter "quantity" for "cart_items" is missing.'));
+            }
+            $qty = (float)$item['quantity'];
+
+            $cartItem = $cart->getItemById($itemId);
+            if ($cartItem === false) {
+                throw new GraphQlNoSuchEntityException(
+                    __('Could not find cart item with id: %1.', $item['cart_item_id'])
+                );
+            }
+
+            if ($qty <= 0.0) {
+                $this->cartItemRepository->deleteById((int)$cart->getId(), $itemId);
+            } else {
+                $cartItem->setQty($qty);
+                $this->cartItemRepository->save($cartItem);
+            }
+        }
+    }
+}

app/code/Magento/QuoteGraphQl/etc/schema.graphqls

@@ -11,6 +11,7 @@ type Mutation {
     addVirtualProductsToCart(input: AddVirtualProductsToCartInput): AddVirtualProductsToCartOutput @resolver(class: "Magento\\QuoteGraphQl\\Model\\Resolver\\AddSimpleProductsToCart")
     applyCouponToCart(input: ApplyCouponToCartInput): ApplyCouponToCartOutput @resolver(class: "\\Magento\\QuoteGraphQl\\Model\\Resolver\\ApplyCouponToCart")
     removeCouponFromCart(input: RemoveCouponFromCartInput): RemoveCouponFromCartOutput @resolver(class: "\\Magento\\QuoteGraphQl\\Model\\Resolver\\RemoveCouponFromCart")
+    updateCartItems(input: UpdateCartItemsInput): UpdateCartItemsOutput @resolver(class: "Magento\\QuoteGraphQl\\Model\\Resolver\\UpdateCartItems")
     removeItemFromCart(input: RemoveItemFromCartInput): RemoveItemFromCartOutput @resolver(class: "Magento\\QuoteGraphQl\\Model\\Resolver\\RemoveItemFromCart")
     setShippingAddressesOnCart(input: SetShippingAddressesOnCartInput): SetShippingAddressesOnCartOutput @resolver(class: "\\Magento\\QuoteGraphQl\\Model\\Resolver\\SetShippingAddressesOnCart")
     setBillingAddressOnCart(input: SetBillingAddressOnCartInput): SetBillingAddressOnCartOutput @resolver(class: "\\Magento\\QuoteGraphQl\\Model\\Resolver\\SetBillingAddressOnCart")
@@ -53,6 +54,11 @@ input ApplyCouponToCartInput {
     coupon_code: String!
 }
 
+input UpdateCartItemsInput {
+    cart_id: String!
+    cart_items: [CartItemQuantityInput!]!
+}
+
 input RemoveItemFromCartInput {
     cart_id: String!
     cart_item_id: Int!
@@ -241,6 +247,10 @@ type AddVirtualProductsToCartOutput {
     cart: Cart!
 }
 
+type UpdateCartItemsOutput {
+    cart: Cart!
+}
+
 type RemoveItemFromCartOutput {
     cart: Cart!
 }

dev/tests/api-functional/testsuite/Magento/GraphQl/Quote/Customer/RemoveItemFromCartTest.php

@@ -75,20 +75,24 @@ public function testRemoveItemFromCart()
 
     /**
      * @magentoApiDataFixture Magento/Customer/_files/customer.php
+     * @magentoApiDataFixture Magento/Checkout/_files/quote_with_simple_product_saved.php
      * @expectedException \Exception
      * @expectedExceptionMessage Could not find a cart with ID "non_existent_masked_id"
      */
     public function testRemoveItemFromNonExistentCart()
     {
-        $query = $this->prepareMutationQuery('non_existent_masked_id', 1);
+        $quote = $this->quoteFactory->create();
+        $this->quoteResource->load($quote, 'test_order_1', 'reserved_order_id');
+        $itemId = (int)$quote->getItemByProduct($this->productRepository->get('simple'))->getId();
 
+        $query = $this->prepareMutationQuery('non_existent_masked_id', $itemId);
         $this->graphQlQuery($query, [], '', $this->getHeaderMap());
     }
 
     /**
      * @magentoApiDataFixture Magento/Checkout/_files/quote_with_address_saved.php
      */
-    public function testRemoveNotExistentItem()
+    public function testRemoveNonExistentItem()
     {
         $quote = $this->quoteFactory->create();
         $this->quoteResource->load($quote, 'test_order_1', 'reserved_order_id');
@@ -183,6 +187,50 @@ public function testRemoveItemFromAnotherCustomerCart()
         $this->graphQlQuery($query, [], '', $this->getHeaderMap());
     }
 
+    /**
+     * @magentoApiDataFixture Magento/Customer/_files/customer.php
+     * @param string $input
+     * @param string $message
+     * @dataProvider dataProviderUpdateWithMissedRequiredParameters
+     */
+    public function testUpdateWithMissedItemRequiredParameters(string $input, string $message)
+    {
+        $query = <<<QUERY
+mutation {
+  removeItemFromCart(
+    input: {
+      {$input}
+    }
+  ) {
+    cart {
+      items {
+        qty
+      }
+    }
+  }
+}
+QUERY;
+        $this->expectExceptionMessage($message);
+        $this->graphQlQuery($query, [], '', $this->getHeaderMap());
+    }
+
+    /**
+     * @return array
+     */
+    public function dataProviderUpdateWithMissedRequiredParameters(): array
+    {
+        return [
+            'missed_cart_id' => [
+                'cart_item_id: 1',
+                'Required parameter "cart_id" is missing.'
+            ],
+            'missed_cart_item_id' => [
+                'cart_id: "test"',
+                'Required parameter "cart_item_id" is missing.'
+            ],
+        ];
+    }
+
     /**
      * @param string $maskedQuoteId
      * @param int $itemId