Small image URL added to the product data

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

@@ -0,0 +1,131 @@
+<?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\Helper\Image as CatalogImageHelper;
+use Magento\Catalog\Model\Product;
+use Magento\Catalog\Model\ResourceModel\Product\GalleryFactory as GalleryResourceFactory;
+use Magento\Framework\App\Area;
+use Magento\Framework\App\AreaList;
+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;
+use Magento\Store\Model\StoreManagerInterface;
+
+/**
+ * Returns product's small image. If the small image is not set, returns a placeholder
+ */
+class SmallImageUrl implements ResolverInterface
+{
+    /**
+     * @var GalleryResourceFactory
+     */
+    private $galleryResourceFactory;
+
+    /**
+     * @var AreaList
+     */
+    private $areaList;
+
+    /**
+     * @var CatalogImageHelper
+     */
+    private $catalogImageHelper;
+
+    /**
+     * @var ValueFactory
+     */
+    private $valueFactory;
+
+    /**
+     * @var StoreManagerInterface
+     */
+    private $storeManager;
+
+    /**
+     * @param ValueFactory $valueFactory
+     * @param CatalogImageHelper $catalogImageHelper
+     * @param AreaList $areaList
+     * @param GalleryResourceFactory $galleryResourceFactory
+     * @param StoreManagerInterface $storeManager
+     */
+    public function __construct(
+        ValueFactory $valueFactory,
+        CatalogImageHelper $catalogImageHelper,
+        AreaList $areaList,
+        GalleryResourceFactory $galleryResourceFactory,
+        StoreManagerInterface $storeManager
+    ) {
+        $this->valueFactory = $valueFactory;
+        $this->catalogImageHelper = $catalogImageHelper;
+        $this->areaList = $areaList;
+        $this->galleryResourceFactory = $galleryResourceFactory;
+        $this->storeManager = $storeManager;
+    }
+
+    /**
+     * {@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 = $value['model'];
+
+        /* If small_image is not loaded for product, need to load it separately */
+        if (!$product->getSmallImage()) {
+            $galleryResource = $this->galleryResourceFactory->create();
+            $currentStoreId =$this->storeManager->getStore()->getId();
+            $productImages = $galleryResource->getProductImages($product, [$currentStoreId]);
+            $productSmallImage = $this->getSmallImageFromGallery($productImages);
+            $product->setSmallImage($productSmallImage);
+        }
+
+        /* Design area is necessary to return the correct storefront image URL (or a placeholder) */
+        $area = $this->areaList->getArea(Area::AREA_FRONTEND);
+        $area->load(Area::PART_DESIGN);
+
+        $smallImageURL = $this->catalogImageHelper->init($product, 'product_small_image')->getUrl();
+        $product->getMediaAttributes();
+
+        $result = function () use ($smallImageURL) {
+            return $smallImageURL;
+        };
+
+        return $this->valueFactory->create($result);
+    }
+
+    /**
+     * Retrieves small image from the product gallery image
+     *
+     * @param array $productImages
+     * @return string|null
+     */
+    private function getSmallImageFromGallery(array $productImages)
+    {
+        foreach ($productImages as $productImage) {
+            if ($productImage['attribute_code'] == 'small_image') {
+                return $productImage['filepath'];
+            }
+        }
+
+        return null;
+    }
+}

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

@@ -259,6 +259,7 @@ interface ProductInterface @typeResolver(class: "Magento\\CatalogGraphQl\\Model\
     meta_description: String @doc(description: "A brief overview of the product for search results listings, maximum 255 characters")
     image: String @doc(description: "The relative path to the main image on the product page")
     small_image: String @doc(description: "The relative path to the small image, which is used on catalog pages")
+    small_image_url: String @doc(description: "The small image URL, which is used on catalog pages") @resolver(class: "Magento\\CatalogGraphQl\\Model\\Resolver\\Product\\SmallImageUrl")
     thumbnail: String @doc(description: "The relative path to the product's thumbnail image")
     new_from_date: String @doc(description: "The beginning date for new product listings, and determines if the product is featured as a new product") @resolver(class: "Magento\\CatalogGraphQl\\Model\\Resolver\\Product\\NewFromTo")
     new_to_date: String @doc(description: "The end date for new product listings") @resolver(class: "Magento\\CatalogGraphQl\\Model\\Resolver\\Product\\NewFromTo")

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

@@ -0,0 +1,85 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\GraphQl\Catalog;
+
+use Magento\TestFramework\TestCase\GraphQlAbstract;
+
+class MediaGalleryTest extends GraphQlAbstract
+{
+    /**
+     * @var \Magento\TestFramework\ObjectManager
+     */
+    private $objectManager;
+
+    protected function setUp()
+    {
+        $this->objectManager = \Magento\TestFramework\Helper\Bootstrap::getObjectManager();
+    }
+
+    /**
+     * @magentoApiDataFixture Magento/Catalog/_files/product_with_image.php
+     */
+    public function testProductSmallImageUrlWithExistingImage()
+    {
+        $productSku = 'simple';
+        $query = <<<QUERY
+{
+  products(filter: {sku: {eq: "{$productSku}"}}) {
+    items {
+   		small_image_url
+    }
+  }    
+}
+QUERY;
+        $response = $this->graphQlQuery($query);
+
+        self::assertArrayHasKey('small_image_url', $response['products']['items'][0]);
+        self::assertContains('magento_image.jpg', $response['products']['items'][0]['small_image_url']);
+        self::assertTrue($this->checkImageExists($response['products']['items'][0]['small_image_url']));
+    }
+
+    /**
+     * small_image_url should contain a placeholder when there's no small image assigned
+     * to the product
+     *
+     * @magentoApiDataFixture Magento/Catalog/_files/product_simple.php
+     */
+    public function testProductSmallImageUrlWithNoImage()
+    {
+        $productSku = 'simple';
+        $query = <<<QUERY
+{
+  products(filter: {sku: {eq: "{$productSku}"}}) {
+    items {
+   		small_image_url
+    }
+  }    
+}
+QUERY;
+        $response = $this->graphQlQuery($query);
+        self::assertArrayHasKey('small_image_url', $response['products']['items'][0]);
+        self::assertContains('placeholder/small_image.jpg', $response['products']['items'][0]['small_image_url']);
+        self::assertTrue($this->checkImageExists($response['products']['items'][0]['small_image_url']));
+    }
+
+    /**
+     * @param string $url
+     * @return bool
+     */
+    private function checkImageExists(string $url): bool
+    {
+        $connection = curl_init($url);
+        curl_setopt($connection, CURLOPT_HEADER, true);
+        curl_setopt($connection, CURLOPT_NOBODY, true);
+        curl_setopt($connection, CURLOPT_RETURNTRANSFER, 1);
+        curl_exec($connection);
+        $responseStatus = curl_getinfo($connection, CURLINFO_HTTP_CODE);
+
+        return $responseStatus === 200 ? true : false;
+    }
+}