Return full canonical product URL within product object

app/code/Magento/CatalogGraphQl/Model/Resolver/Product/CanonicalUrl.php

@@ -0,0 +1,62 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\CatalogGraphQl\Model\Resolver\Product;
+
+use Magento\Catalog\Model\Product;
+use Magento\Framework\GraphQl\Config\Element\Field;
+use Magento\Framework\GraphQl\Query\Resolver\Value;
+use Magento\Framework\GraphQl\Query\Resolver\ValueFactory;
+use Magento\Framework\GraphQl\Query\ResolverInterface;
+use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
+
+/**
+ * Resolve data for product canonical URL
+ */
+class CanonicalUrl implements ResolverInterface
+{
+    /**
+     * @var ValueFactory
+     */
+    private $valueFactory;
+
+    /**
+     * @param ValueFactory $valueFactory
+     */
+    public function __construct(
+        ValueFactory $valueFactory
+    ) {
+        $this->valueFactory = $valueFactory;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function resolve(
+        Field $field,
+        $context,
+        ResolveInfo $info,
+        array $value = null,
+        array $args = null
+    ): Value {
+        if (!isset($value['model'])) {
+            $result = function () {
+                return null;
+            };
+            return $this->valueFactory->create($result);
+        }
+
+        /* @var $product Product */
+        $product = $value['model'];
+        $url = $product->getUrlModel()->getUrl($product, ['_ignore_category' => true]);
+        $result = function () use ($url) {
+            return $url;
+        };
+
+        return $this->valueFactory->create($result);
+    }
+}

app/code/Magento/CatalogGraphQl/Test/Unit/Model/Resolver/Product/CanonicalUrlTest.php

@@ -0,0 +1,92 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\CatalogGraphQl\Test\Unit\Model\Resolver\Product;
+
+use Magento\CatalogGraphQl\Model\Resolver\Product\CanonicalUrl;
+use Magento\CatalogUrlRewrite\Model\ProductUrlPathGenerator;
+use Magento\Framework\GraphQl\Query\Resolver\Value;
+use Magento\Framework\GraphQl\Query\Resolver\ValueFactory;
+use Magento\Framework\TestFramework\Unit\Helper\ObjectManager;
+use Magento\Store\Model\StoreManagerInterface;
+use PHPUnit\Framework\TestCase;
+
+class CanonicalUrlTest extends TestCase
+{
+    /**
+     * @var ObjectManager
+     */
+    private $objectManager;
+
+    /**
+     * @var CanonicalUrl
+     */
+    private $subject;
+
+    /**
+     * @var \PHPUnit_Framework_MockObject_MockObject
+     */
+    private $mockValueFactory;
+
+    /**
+     * @var \PHPUnit_Framework_MockObject_MockObject
+     */
+    private $mockStoreManager;
+
+    public function testReturnsNullWhenNoProductAvailable()
+    {
+        $mockField = $this->getMockBuilder(\Magento\Framework\GraphQl\Config\Element\Field::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $mockInfo = $this->getMockBuilder(\Magento\Framework\GraphQl\Schema\Type\ResolveInfo::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $this->mockValueFactory->method('create')->with(
+            $this->callback(
+                function ($param) {
+                    return $param() === null;
+                }
+            )
+        );
+
+        $this->subject->resolve($mockField, '', $mockInfo, [], []);
+    }
+
+    protected function setUp()
+    {
+        parent::setUp();
+        $this->objectManager = new ObjectManager($this);
+        $this->mockStoreManager = $this->getMockBuilder(StoreManagerInterface::class)->getMock();
+        $this->mockValueFactory = $this->getMockBuilder(ValueFactory::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $this->mockValueFactory->method('create')->willReturn(
+            $this->objectManager->getObject(
+                Value::class,
+                ['callback' => function () {
+                    return '';
+                }]
+            )
+        );
+
+        $mockProductUrlPathGenerator = $this->getMockBuilder(ProductUrlPathGenerator::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $mockProductUrlPathGenerator->method('getUrlPathWithSuffix')->willReturn('product_url.html');
+
+        $this->subject = $this->objectManager->getObject(
+            CanonicalUrl::class,
+            [
+                'valueFactory' => $this->mockValueFactory,
+                'storeManager' => $this->mockStoreManager,
+                'productUrlPathGenerator' => $mockProductUrlPathGenerator
+            ]
+        );
+    }
+}

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

@@ -279,6 +279,7 @@ interface ProductInterface @typeResolver(class: "Magento\\CatalogGraphQl\\Model\
     gift_message_available: String @doc(description: "Indicates whether a gift message is available")
     manufacturer: Int @doc(description: "A number representing the product's manufacturer")
     categories: [CategoryInterface] @doc(description: "The categories assigned to a product") @resolver(class: "Magento\\CatalogGraphQl\\Model\\Resolver\\Category")
+    canonical_url: String @doc(description: "Canonical URL") @resolver(class: "Magento\\CatalogGraphQl\\Model\\Resolver\\Product\\CanonicalUrl")
 }
 
 interface PhysicalProductInterface @typeResolver(class: "Magento\\CatalogGraphQl\\Model\\ProductInterfaceTypeResolverComposite") @doc(description: "PhysicalProductInterface contains attributes specific to tangible products") {

dev/tests/api-functional/testsuite/Magento/GraphQl/Catalog/ProductViewTest.php

@@ -227,6 +227,7 @@ public function testQueryAllFieldsSimpleProduct()
             updated_at
             url_key
             url_path
+            canonical_url
             websites { id name code sort_order default_group_id is_default }
             ... on PhysicalProductInterface {
                 weight
@@ -272,6 +273,11 @@ public function testQueryAllFieldsSimpleProduct()
             'Filter category',
             $responseObject->getData('products/items/0/categories/2/name')
         );
+        $storeManager = ObjectManager::getInstance()->get(\Magento\Store\Model\StoreManagerInterface::class);
+        self::assertEquals(
+            $storeManager->getStore()->getBaseUrl() . 'simple-product.html',
+            $responseObject->getData('products/items/0/canonical_url')
+        );
     }
 
     /**