S3fsImageStyleDownloadController.php in S3 File System 8.3

Namespace

Drupal\s3fs\Controller

File

src/Controller/S3fsImageStyleDownloadController.php

<?php

namespace Drupal\s3fs\Controller;

use Drupal\Component\Utility\Crypt;
use Drupal\Core\Cache\Cache;
use Drupal\Core\Routing\TrustedRedirectResponse;
use Drupal\image\Controller\ImageStyleDownloadController;
use Drupal\image\ImageStyleInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
use Symfony\Component\HttpKernel\Exception\ServiceUnavailableHttpException;

/**
 * Defines a controller to serve public/s3 Amazon S3 image styles.
 */
class S3fsImageStyleDownloadController extends ImageStyleDownloadController {

  /**
   * Generates a Amazon S3 derivative, given a style and image path.
   *
   * After generating an image, redirect it to the requesting agent. Only used
   * for public or s3 schemes. Private scheme use the normal workflow:
   * \Drupal\image\Controller\ImageStyleDownloadController::deliver().
   *
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The request object.
   * @param string $scheme
   *   The file scheme.
   * @param \Drupal\image\ImageStyleInterface $image_style
   *   The image style to deliver.
   *
   * @return \Drupal\Core\Routing\TrustedRedirectResponse|\Symfony\Component\HttpFoundation\Response
   *   The redirect response or some error response.
   *
   * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
   *   Thrown when the user does not have access to the file.
   * @throws \Symfony\Component\HttpKernel\Exception\ServiceUnavailableHttpException
   *   Thrown when the file is still being generated.
   *
   * @see \Drupal\image\Controller\ImageStyleDownloadController::deliver()
   */
  public function deliver(Request $request, $scheme, ImageStyleInterface $image_style) {
    $target = $request->query
      ->get('file');
    $image_uri = $scheme . '://' . $target;

    // Check that the style is defined, the scheme is valid, and the image
    // derivative token is valid. Sites which require image derivatives to be
    // generated without a token can set the
    // 'image.settings:allow_insecure_derivatives' configuration to TRUE to
    // bypass the latter check, but this will increase the site's vulnerability
    // to denial-of-service attacks. To prevent this variable from leaving the
    // site vulnerable to the most serious attacks, a token is always required
    // when a derivative of a style is requested.
    // The $target variable for a derivative of a style has
    // styles/<style_name>/... as structure, so we check if the $target variable
    // starts with styles/.
    $valid = !empty($image_style) && \Drupal::service('stream_wrapper_manager')
      ->isValidScheme($scheme);
    if (!$this
      ->config('image.settings')
      ->get('allow_insecure_derivatives') || strpos(ltrim($target, '\\/'), 'styles/') === 0) {
      $valid &= hash_equals($request->query
        ->get(IMAGE_DERIVATIVE_TOKEN), $image_style
        ->getPathToken($image_uri));
    }
    if (!$valid) {
      throw new AccessDeniedHttpException();
    }
    $derivative_uri = $image_style
      ->buildUri($image_uri);

    // Private scheme use:
    // \Drupal\image\Controller\ImageStyleDownloadController::deliver()
    // instead of this.
    if ($scheme == 'private') {
      throw new AccessDeniedHttpException();
    }

    // Don't try to generate file if source is missing.
    if (!file_exists($image_uri)) {

      // If the image style converted the extension, it has been added to the
      // original file, resulting in filenames like image.png.jpeg. So to find
      // the actual source image, we remove the extension and check if that
      // image exists.
      $path_info = pathinfo($image_uri);
      $converted_image_uri = $path_info['dirname'] . DIRECTORY_SEPARATOR . $path_info['filename'];
      if (!file_exists($converted_image_uri)) {
        $this->logger
          ->notice('Source image at %source_image_path not found while trying to generate derivative image at %derivative_path.', [
          '%source_image_path' => $image_uri,
          '%derivative_path' => $derivative_uri,
        ]);
        return new Response($this
          ->t('Error generating image, missing source file.'), 404);
      }
      else {

        // The converted file does exist, use it as the source.
        $image_uri = $converted_image_uri;
      }
    }

    // Don't start generating the image if the derivative already exists or if
    // generation is in progress in another thread.
    if (!file_exists($derivative_uri)) {
      $lock_name = 's3fs_image_style_deliver:' . $image_style
        ->id() . ':' . Crypt::hashBase64($image_uri);
      $lock_acquired = $this->lock
        ->acquire($lock_name);
      if (!$lock_acquired) {

        // Tell client to retry again in 3 seconds. Currently no browsers are
        // known to support Retry-After.
        throw new ServiceUnavailableHttpException(3, $this
          ->t('Image generation in progress. Try again shortly.'));
      }
    }

    // Try to generate the image, unless another thread just did it while we
    // were acquiring the lock.
    $success = file_exists($derivative_uri);
    if (!$success) {

      // If we successfully generate the derivative, wait until S3 acknowledges
      // its existence. Otherwise, redirecting to it may cause a 403 error.
      $success = $image_style
        ->createDerivative($image_uri, $derivative_uri) && \Drupal::service('stream_wrapper_manager')
        ->getViaScheme('s3')
        ->waitUntilFileExists($derivative_uri);
    }
    if (!empty($lock_acquired)) {
      $this->lock
        ->release($lock_name);
    }
    if ($success) {
      $responseCacheTags = $image_style
        ->getCacheTags();

      // Try to get a managed file and flush the cache.
      $storage = $this
        ->entityTypeManager()
        ->getStorage('file');
      $result = $storage
        ->getQuery()
        ->condition('uri', $image_uri, '=')
        ->execute();
      if (!empty($result)) {
        $file = $storage
          ->load(reset($result));
        Cache::invalidateTags($file
          ->getCacheTags());
        $responseCacheTags = Cache::mergeTags($responseCacheTags, $file
          ->getCacheTags());
      }

      // Perform a 302 Redirect to the new image derivative in S3.
      // It must be TrustedRedirectResponse for external redirects.
      $response = new TrustedRedirectResponse($image_style
        ->buildUrl($image_uri));
      $cacheableMetadata = $response
        ->getCacheableMetadata();
      $cacheableMetadata
        ->addCacheContexts([
        'url.query_args:file',
        'url.query_args:itok',
      ]);
      $cacheableMetadata
        ->setCacheMaxAge((int) $this
        ->config('s3fs.settings')
        ->get('redirect_styles_ttl'));
      $cacheableMetadata
        ->setCacheTags($responseCacheTags);
      $response
        ->addCacheableDependency($cacheableMetadata);
      return $response;
    }
    else {
      $this->logger
        ->notice('Unable to generate the derived image located at %path.', [
        '%path' => $derivative_uri,
      ]);
      return new Response($this
        ->t('Error generating image.'), 500);
    }
  }

}

Classes

Name	Description
S3fsImageStyleDownloadController	Defines a controller to serve public/s3 Amazon S3 image styles.