PWA-806: Localize emails sent through GraphQL application

Author: davemacaulay

app/code/Magento/GraphQl/Plugin/StoreResolver.php

@@ -0,0 +1,82 @@
+<?php
+
+namespace Magento\GraphQl\Plugin;
+
+use Magento\Framework\App\Request\Http as HttpRequest;
+use Magento\Framework\App\RequestInterface;
+use Magento\Framework\Exception\NoSuchEntityException;
+use Magento\Store\Api\Data\StoreInterface;
+use Magento\Store\Api\StoreRepositoryInterface;
+use Magento\Store\Model\StoreIsInactiveException;
+
+/**
+ * Load translations for GraphQL requests
+ */
+class StoreResolver
+{
+    /**
+     * @var RequestInterface|HttpRequest
+     */
+    private $request;
+
+    /**
+     * @var StoreRepositoryInterface
+     */
+    private $storeRepository;
+
+    /**
+     * @param RequestInterface $request
+     * @param StoreRepositoryInterface $storeRepository
+     */
+    public function __construct(
+        RequestInterface $request,
+        StoreRepositoryInterface $storeRepository
+    ) {
+        $this->request = $request;
+        $this->storeRepository = $storeRepository;
+    }
+
+    /**
+     * Use the 'Store' header to determine the current store
+     *
+     * @param \Magento\Store\Model\StoreResolver $subject
+     * @param callable $proceed
+     * @return mixed
+     */
+    public function aroundGetCurrentStoreId(\Magento\Store\Model\StoreResolver $subject, callable $proceed)
+    {
+        $storeCode = $this->request->getHeader('Store');
+
+        if ($storeCode) {
+            try {
+                $store = $this->getRequestedStoreByCode($storeCode);
+
+                if ($store) {
+                    return $store;
+                }
+            } catch (NoSuchEntityException $e) {
+                return $proceed();
+            }
+        }
+
+        return $proceed();
+    }
+
+    /**
+     * Retrieve active store by code
+     *
+     * @param string $storeCode
+     * @return StoreInterface
+     * @throws NoSuchEntityException
+     */
+    private function getRequestedStoreByCode($storeCode) : StoreInterface
+    {
+        try {
+            $store = $this->storeRepository->getActiveStoreByCode($storeCode);
+        } catch (StoreIsInactiveException $e) {
+            throw new NoSuchEntityException(__('Requested store is inactive'));
+        }
+
+        return $store;
+    }
+}

app/code/Magento/GraphQl/Plugin/TranslationLoader.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace Magento\GraphQl\Plugin;
+
+use Magento\Framework\App\AreaInterface;
+use Magento\Framework\App\AreaList;
+use Magento\Framework\App\ObjectManager;
+use Magento\Framework\App\State;
+use Magento\Store\Model\StoreManagerInterface;
+
+/**
+ * Load translations for GraphQL requests
+ */
+class TranslationLoader
+{
+    /**
+     * @var AreaList
+     */
+    private $areaList;
+
+    /**
+     * @var State
+     */
+    private $appState;
+
+    /**
+     * @param AreaList $areaList
+     * @param State $appState
+     */
+    public function __construct(
+        AreaList $areaList,
+        State $appState
+    ) {
+        $this->areaList = $areaList;
+        $this->appState = $appState;
+    }
+
+    /**
+     * Before rendering any string ensure the translation aspect of area is loaded
+     */
+    public function beforeRender(\Magento\Framework\Phrase $subject)
+    {
+        $area = $this->areaList->getArea($this->appState->getAreaCode());
+        $area->load(AreaInterface::PART_TRANSLATE);
+    }
+}

app/code/Magento/GraphQl/etc/graphql/di.xml

@@ -41,4 +41,10 @@
             </argument>
         </arguments>
     </type>
+    <type name="Magento\Framework\Phrase">
+        <plugin name="graphQlLocalizationPhrasePlugin" type="Magento\GraphQl\Plugin\TranslationLoader" />
+    </type>
+    <type name="Magento\Store\Model\StoreResolver">
+        <plugin name="graphQlLocalizationStoreResolver" type="Magento\GraphQl\Plugin\StoreResolver" />
+    </type>
 </config>

lib/internal/Magento/Framework/Phrase/__.php

@@ -3,15 +3,19 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+
 declare(strict_types=1);
 
+use Magento\Framework\App\ObjectManager;
+use Magento\Framework\Phrase;
+
 /**
  * Create value-object \Magento\Framework\Phrase
  *
  * @SuppressWarnings(PHPMD.ShortMethodName)
  * phpcs:disable Squiz.Functions.GlobalFunction
  * @param array $argc
- * @return \Magento\Framework\Phrase
+ * @return Phrase
  */
 function __(...$argc)
 {
@@ -20,5 +24,11 @@ function __(...$argc)
         $argc = $argc[0];
     }
 
-    return new \Magento\Framework\Phrase($text, $argc);
+    return ObjectManager::getInstance()->create(
+        Phrase::class,
+        [
+            'text' => $text,
+            'arguments' => $argc
+        ]
+    );
 }