Issue #3409475: Add Symfony Messenger support for async messages (emails as queues)

src/Plugin/Mail/SymfonyMailer.php

@@ -15,24 +15,25 @@ use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\File\FileSystemInterface;
 use Drupal\Core\Mail\MailInterface;
+use Drupal\Core\Mail\MailManagerInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\Render\Markup;
 use Drupal\Core\Render\RendererInterface;
 use Drupal\Core\Site\Settings;
+use Drupal\Core\Theme\ThemeManagerInterface;
+use Drupal\mailsystem\MailsystemManager;
 use Drupal\symfony_mailer_lite\EmbeddedImage;
 use Drupal\symfony_mailer_lite\EmbeddedImageValidatorInterface;
 use Html2Text\Html2Text;
 use Psr\Log\LoggerInterface;
 use stdClass;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\Mailer\MailerInterface;
 use Symfony\Component\Mailer\Exception\TransportExceptionInterface;
 use Symfony\Component\Mime\Address;
+use Symfony\Component\Mime\Email;
 use Symfony\Component\Mime\Part\DataPart;
 use TijsVerkoyen\CssToInlineStyles\CssToInlineStyles;
-use Drupal\Core\Theme\ThemeManagerInterface;
-use Drupal\Core\Mail\MailManagerInterface;
-use Drupal\mailsystem\MailsystemManager;
-use Symfony\Component\Mime\Email;
 
 /**
  * Provides a 'Drupal Symfony Mailer Lite' plugin to send emails.
@@ -128,6 +129,11 @@ class SymfonyMailer implements MailInterface, ContainerFactoryPluginInterface {
    */
   protected $embeddedImageValidator;
 
+  /**
+   * @var \Symfony\Component\Mailer\MailerInterface
+   */
+  private MailerInterface $mailer;
+
   /**
    * @param EntityTypeManagerInterface $entity_type_manager
    * @param ConfigFactoryInterface $config_factory
@@ -141,7 +147,7 @@ class SymfonyMailer implements MailInterface, ContainerFactoryPluginInterface {
    * @param $mime_type_guesser
    * @param AssetOptimizerInterface|null $cssOptimizer
    */
-  public function __construct(EntityTypeManagerInterface $entity_type_manager, ConfigFactoryInterface $config_factory, LoggerInterface $logger, RendererInterface $renderer, ModuleHandlerInterface $module_handler, MailManagerInterface $mail_manager, ThemeManagerInterface $theme_manager, AssetResolverInterface $asset_resolver, EmbeddedImageValidatorInterface $embedded_image_validator, AssetOptimizerInterface $cssOptimizer = NULL) {
+  public function __construct(EntityTypeManagerInterface $entity_type_manager, ConfigFactoryInterface $config_factory, LoggerInterface $logger, RendererInterface $renderer, ModuleHandlerInterface $module_handler, MailManagerInterface $mail_manager, ThemeManagerInterface $theme_manager, AssetResolverInterface $asset_resolver, EmbeddedImageValidatorInterface $embedded_image_validator, MailerInterface $mailer, AssetOptimizerInterface $cssOptimizer = NULL) {
     $this->entityTypeManager = $entity_type_manager;
     $this->configFactory = $config_factory;
     $this->logger = $logger;
@@ -153,6 +159,7 @@ class SymfonyMailer implements MailInterface, ContainerFactoryPluginInterface {
     $this->cssInliner = new CssToInlineStyles();
     $this->cssOptimizer = $cssOptimizer;
     $this->embeddedImageValidator = $embedded_image_validator;
+    $this->mailer = $mailer;
   }
 
   /**
@@ -169,7 +176,8 @@ class SymfonyMailer implements MailInterface, ContainerFactoryPluginInterface {
       $container->get('theme.manager'),
       $container->get('asset.resolver'),
       $container->get('symfony_mailer_lite.embedded_image_validator'),
-      $container->get('asset.css.optimizer')
+      $container->get('symfony_mailer_lite.mailer'),
+      $container->get('asset.css.optimizer'),
     );
   }
 
@@ -244,18 +252,15 @@ class SymfonyMailer implements MailInterface, ContainerFactoryPluginInterface {
    *   TRUE if the message was successfully sent, and otherwise FALSE.
    */
   public function mail(array $message) {
-    if (!empty($message['symfony_mailer_lite_transport'])) {
-      $transport_id = $message['symfony_mailer_lite_transport'];
-    }
-    else {
-      $transport_id = $this->configFactory->get('symfony_mailer_lite.settings')->get('default_transport');
-    }
-    $transport_entity = \Drupal::entityTypeManager()->getStorage('symfony_mailer_lite_transport')->load($transport_id);
-    $transport = \Symfony\Component\Mailer\Transport::fromDsn($transport_entity->getDsn());
-    $mailer = new \Symfony\Component\Mailer\Mailer($transport, NULL, NULL);
     try {
-
       $email = new Email();
+
+      $customTransport = $message['symfony_mailer_lite_transport'] ?? NULL;
+      if ($customTransport !== NULL) {
+        // https://symfony.com/doc/current/mailer.html#multiple-email-transports
+        $email->getHeaders()->addTextHeader('X-Transport', $customTransport);
+      }
+
       if (!empty($message['subject'])) {
         $email->subject($message['subject']);
       }
@@ -387,7 +392,7 @@ class SymfonyMailer implements MailInterface, ContainerFactoryPluginInterface {
       }
 
       // Send the message.
-      $mailer->send($email);
+      $this->mailer->send($email);
       return TRUE;
     }
     catch (TransportExceptionInterface $e) {

src/TransportsFactory.php

+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\symfony_mailer_lite;
+
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Symfony\Component\Mailer\Transport;
+use Symfony\Component\Mailer\Transport\Transports;
+
+/**
+ * Repository of mailer transport DSNs.
+ */
+final class TransportsFactory {
+
+  /**
+   * @var ConfigFactoryInterface
+   */
+  protected ConfigFactoryInterface $configFactory;
+
+  /**
+   * @var EntityTypeManagerInterface
+   */
+  protected EntityTypeManagerInterface $entityTypeManager;
+
+  /**
+   * Constructs a new TransportsFactory.
+   */
+  public function __construct(ConfigFactoryInterface $configFactory, EntityTypeManagerInterface $entityTypeManager) {
+    $this->entityTypeManager = $entityTypeManager;
+    $this->configFactory = $configFactory;
+  }
+
+  /**
+   * Get the collection of all transports.
+   *
+   * An object must always be returned, even if transport configuration is
+   * invalid or missing transports.
+   */
+  public function create(): Transports {
+    /** @var \Drupal\symfony_mailer_lite\Entity\Transport[] $transportConfigs */
+    $transportConfigs = $this->entityTypeManager->getStorage('symfony_mailer_lite_transport')->loadMultiple();
+    $transportConfigs = array_filter($transportConfigs, fn (Entity\Transport $transportConfig): bool => $transportConfig->status() === TRUE);
+    $dsns = array_map(fn (Entity\Transport $transportConfig): string => $transportConfig->getDsn(), $transportConfigs);
+
+    // The default transport must always be the first.
+    // @see \Symfony\Component\Mailer\Transport\Transports::__construct
+    $defaultTransportId = $this->configFactory->get('symfony_mailer_lite.settings')->get('default_transport');
+    if (isset($dsns[$defaultTransportId])) {
+      $defaultDsn = $dsns[$defaultTransportId];
+      unset($dsns[$defaultTransportId]);
+      // Unshift the default with key to the front of the DSN list.
+      $dsns = [$defaultTransportId => $defaultDsn] + $dsns;
+    }
+    else {
+      // If the default transport mapping no longer exists, unset everything
+      // until a new default transport is created and/or nominated.
+      $dsns = [];
+    }
+
+    // If nothing was configured, create a null transport.
+    if (count($dsns) === 0) {
+      $dsns = [
+        'null' => 'null://null',
+      ];
+    }
+
+    try {
+      return Transport::fromDsns($dsns);
+    }
+    catch (\Exception $e) {
+      // A Transports object with at least one transport must be returned.
+      return Transport::fromDsns([
+        'null://null',
+      ]);
+    }
+  }
+
+}

symfony_mailer_lite.services.yml

@@ -6,3 +6,27 @@ services:
   symfony_mailer_lite.embedded_image_validator:
     class: Drupal\symfony_mailer_lite\EmbeddedImageValidator
     arguments: ['@file_system', '@file.mime_type.guesser']
+
+  # Mailer.
+  symfony_mailer_lite.transports_factory:
+    class: Drupal\symfony_mailer_lite\TransportsFactory
+    arguments: [ '@config.factory', '@entity_type.manager' ]
+    public: false
+
+  symfony_mailer_lite.transports:
+    class: Symfony\Component\Mailer\Transport\Transports
+    factory: [ '@symfony_mailer_lite.transports_factory', 'create' ]
+    public: false
+
+  symfony_mailer_lite.mailer:
+    class: Symfony\Component\Mailer\Mailer
+    arguments: [ '@symfony_mailer_lite.transports', '@?messenger.default_bus', '@event_dispatcher' ]
+  Symfony\Component\Mailer\MailerInterface: '@symfony_mailer_lite.mailer'
+
+  # Optional messenger integration.
+  mailer.messenger.message_handler:
+    class: Symfony\Component\Mailer\Messenger\MessageHandler
+    arguments: ['@symfony_mailer_lite.transports']
+    tags:
+      - { name: messenger.message_handler }
+    public: false