Migrate to new hook

Closes #3526226

modules/file_attachment/src/Plugin/Field/FieldFormatter/MdFileAttachmentFieldFormatter.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\markdownify_file_attachment\Plugin\Field\FieldFormatter;
+
+use Drupal\Core\Field\FieldItemListInterface;
+use Drupal\Core\File\FileSystemInterface;
+use Drupal\Core\File\FileUrlGeneratorInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\Core\Render\RenderContext;
+use Drupal\Core\Render\RendererInterface;
+use Drupal\file\Plugin\Field\FieldFormatter\FileFormatterBase;
+use Drupal\file\Plugin\Field\FieldType\FileFieldItemList;
+use Psr\Log\LoggerInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Plugin implementation of the 'entity_reference_file_attachment' formatter.
+ *
+ * @FieldFormatter(
+ *   id = "md_file_attachment_file_embed",
+ *   label = @Translation("Embed file as Markdown"),
+ *   field_types = {
+ *     "file"
+ *   }
+ * )
+ */
+final class MdFileAttachmentFieldFormatter extends FileFormatterBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * File URL generator.
+   *
+   * @var \Drupal\Core\File\FileUrlGeneratorInterface
+   */
+  private FileUrlGeneratorInterface $fileUrlGenerator;
+
+  /**
+   * Renderer interface.
+   *
+   * @var \Drupal\Core\Render\RendererInterface
+   */
+  private RendererInterface $renderer;
+
+  /**
+   * Logger interface.
+   *
+   * @var \Psr\Log\LoggerInterface
+   */
+  private LoggerInterface $logger;
+
+  /**
+   * File system interface.
+   *
+   * @var \Drupal\Core\File\FileSystemInterface
+   */
+  private FileSystemInterface $fileSystem;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): self {
+    $instance = new self(
+      $plugin_id,
+      $plugin_definition,
+      $configuration['field_definition'],
+      $configuration['settings'],
+      $configuration['label'],
+      $configuration['view_mode'],
+      $configuration['third_party_settings'],
+    );
+
+    $instance->fileUrlGenerator = $container->get('file_url_generator');
+    $instance->renderer = $container->get('renderer');
+    $instance->logger = $container->get('logger.channel.markdownify');
+    $instance->fileSystem = $container->get('file_system');
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function defaultSettings(): array {
+    return [
+      'allowed_extensions' => ['yml', 'txt'],
+      'max_size' => 1024,
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function viewElements(FieldItemListInterface $items, $langcode): array {
+    assert($items instanceof FileFieldItemList);
+    $element = [];
+
+    $allowed_extensions = $this->getSetting('allowed_extensions');
+    $max_size = $this->getSetting('max_size');
+
+    foreach ($this->getEntitiesToView($items, $langcode) as $delta => $file) {
+
+      if (!$file) {
+        continue;
+      }
+
+      $file_size = $file->getSize();
+      $file_name = $file->getFilename();
+      $extension = strtolower(pathinfo($file_name, PATHINFO_EXTENSION));
+      $uri = $file->getFileUri();
+      $url = '';
+      try {
+        $context = new RenderContext();
+        $url = $this->renderer->executeInRenderContext($context, function () use ($uri) {
+          return $this->fileUrlGenerator->generateAbsoluteString($uri);
+        });
+      }
+      catch (\Exception $e) {
+        $this->logger->error('Failed to render file URL: @message', ['@message' => $e->getMessage()]);
+      }
+
+      $real_path = $this->fileSystem->realpath($uri);
+
+      if (in_array($extension, $allowed_extensions, TRUE) && $file_size <= $max_size) {
+        $content = @file_get_contents($real_path);
+        $element[$delta] = [
+          '#type' => 'markup',
+          '#markup' => $this->t('Attached file %filename with %extension extension available at %url follows:<br>%file', [
+            '%filename' => $file_name,
+            '%extension' => $extension,
+            '%file' => $content,
+            '%url' => $url,
+          ]),
+        ];
+      }
+      else {
+        $element[$delta] = [
+          '#type' => 'markup',
+          '#markup' => $this->t('Attached file %filename with %extension extension available at %url', [
+            '%filename' => $file_name,
+            '%extension' => $extension,
+            '%url' => $url,
+          ]),
+        ];
+      }
+
+    }
+
+    return $element;
+  }
+
+}