public function S3fsImageStyleDownloadController::deliver in S3 File System 4.0.x

Same name and namespace in other branches

1. 8.3 src/Controller/S3fsImageStyleDownloadController.php \Drupal\s3fs\Controller\S3fsImageStyleDownloadController::deliver()

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().

Parameters

\Symfony\Component\HttpFoundation\Request $request: The request object.

string $scheme: The file scheme.

\Drupal\image\ImageStyleInterface $image_style: The image style to deliver.

Return value

\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.

\Symfony\Component\HttpKernel\Exception\ServiceUnavailableHttpException Thrown when the file is still being generated.

Overrides ImageStyleDownloadController::deliver

See also

\Drupal\image\Controller\ImageStyleDownloadController::deliver()

File

src/Controller/S3fsImageStyleDownloadController.php, line 44

Class

S3fsImageStyleDownloadController

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

Namespace

Drupal\s3fs\Controller

Code

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);
  }
}