MC-32387: Add pagination support to categoryList query

- review comments
- add caching

Author: danielrenaud

app/code/Magento/CatalogGraphQl/Model/Resolver/Category/CategoriesIdentity.php

@@ -7,6 +7,7 @@
 
 namespace Magento\CatalogGraphQl\Model\Resolver\Category;
 
+use Magento\Catalog\Model\Category;
 use Magento\Framework\GraphQl\Query\Resolver\IdentityInterface;
 
 /**
@@ -15,7 +16,7 @@
 class CategoriesIdentity implements IdentityInterface
 {
     /** @var string */
-    private $cacheTag = \Magento\Catalog\Model\Category::CACHE_TAG;
+    private $cacheTag = Category::CACHE_TAG;
 
     /**
      * Get category IDs from resolved data
@@ -26,8 +27,9 @@ class CategoriesIdentity implements IdentityInterface
     public function getIdentities(array $resolvedData): array
     {
         $ids = [];
-        if (!empty($resolvedData)) {
-            foreach ($resolvedData as $category) {
+        $resolvedCategories = $resolvedData['items'] ?? $resolvedData;
+        if (!empty($resolvedCategories)) {
+            foreach ($resolvedCategories as $category) {
                 $ids[] = sprintf('%s_%s', $this->cacheTag, $category['id']);
             }
             if (!empty($ids)) {

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

@@ -21,7 +21,7 @@ type Query {
         filters: CategoryFilterInput @doc(description: "Identifies which Category filter inputs to search for and return.")
         pageSize: Int = 20 @doc(description: "Specifies the maximum number of results to return at once. This attribute is optional.")
         currentPage: Int = 1 @doc(description: "Specifies which page of results to return. The default value is 1.")
-    ): CategoryResult @resolver(class: "Magento\\CatalogGraphQl\\Model\\Resolver\\CategoriesQuery")
+    ): CategoryResult @resolver(class: "Magento\\CatalogGraphQl\\Model\\Resolver\\CategoriesQuery") @cache(cacheIdentity: "Magento\\CatalogGraphQl\\Model\\Resolver\\Category\\CategoriesIdentity")
 }
 
 type Price @doc(description: "Price is deprecated, replaced by ProductPrice. The Price object defines the price of a product as well as any tax-related adjustments.") {
@@ -138,8 +138,8 @@ type CategoryTree implements CategoryInterface @doc(description: "Category Tree
     children: [CategoryTree] @doc(description: "Child categories tree.") @resolver(class: "Magento\\CatalogGraphQl\\Model\\Resolver\\CategoryTree")
 }
 
-type CategoryResult @doc(description: "Collection of CategoryTree object and pagination information.") {
-    items: [CategoryTree] @doc(description: "List of categories that match filter criteria.")
+type CategoryResult @doc(description: "A collection of CategoryTree objects and pagination information.") {
+    items: [CategoryTree] @doc(description: "A list of categories that match the filter criteria.")
     page_info: SearchResultPageInfo @doc(description: "An object that includes the page_info and currentPage values specified in the query.")
     total_count: Int @doc(description: "The total number of categories that match the criteria.")
 }