ImageStyleDownloadController.php in Zircon Profile 8

Contains \Drupal\image\Controller\ImageStyleDownloadController.

Namespace

Drupal\image\Controller

File

core/modules/image/src/Controller/ImageStyleDownloadController.php

<?php

/**
 * @file
 * Contains \Drupal\image\Controller\ImageStyleDownloadController.
 */
namespace Drupal\image\Controller;

use Drupal\Component\Utility\Crypt;
use Drupal\Core\Image\ImageFactory;
use Drupal\Core\Lock\LockBackendInterface;
use Drupal\image\ImageStyleInterface;
use Drupal\system\FileDownloadController;
use Psr\Log\LoggerInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Symfony\Component\HttpFoundation\BinaryFileResponse;
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 image styles.
 */
class ImageStyleDownloadController extends FileDownloadController {

  /**
   * The lock backend.
   *
   * @var \Drupal\Core\Lock\LockBackendInterface
   */
  protected $lock;

  /**
   * The image factory.
   *
   * @var \Drupal\Core\Image\ImageFactory
   */
  protected $imageFactory;

  /**
   * A logger instance.
   *
   * @var \Psr\Log\LoggerInterface
   */
  protected $logger;

  /**
   * Constructs a ImageStyleDownloadController object.
   *
   * @param \Drupal\Core\Lock\LockBackendInterface $lock
   *   The lock backend.
   * @param \Drupal\Core\Image\ImageFactory $image_factory
   *   The image factory.
   * @param \Psr\Log\LoggerInterface $logger
   *   A logger instance.
   */
  public function __construct(LockBackendInterface $lock, ImageFactory $image_factory, LoggerInterface $logger) {
    $this->lock = $lock;
    $this->imageFactory = $image_factory;
    $this->logger = $logger;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static($container
      ->get('lock'), $container
      ->get('image.factory'), $container
      ->get('logger.factory')
      ->get('image'));
  }

  /**
   * Generates a derivative, given a style and image path.
   *
   * After generating an image, transfer it to the requesting agent.
   *
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The request object.
   * @param string $scheme
   *   The file scheme, defaults to 'private'.
   * @param \Drupal\image\ImageStyleInterface $image_style
   *   The image style to deliver.
   *
   * @return \Symfony\Component\HttpFoundation\BinaryFileResponse|\Symfony\Component\HttpFoundation\Response
   *   The transferred file as 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.
   */
  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) && file_stream_wrapper_valid_scheme($scheme);
    if (!$this
      ->config('image.settings')
      ->get('allow_insecure_derivatives') || strpos(ltrim($target, '\\/'), 'styles/') === 0) {
      $valid &= $request->query
        ->get(IMAGE_DERIVATIVE_TOKEN) === $image_style
        ->getPathToken($image_uri);
    }
    if (!$valid) {
      throw new AccessDeniedHttpException();
    }
    $derivative_uri = $image_style
      ->buildUri($image_uri);
    $headers = array();

    // If using the private scheme, let other modules provide headers and
    // control access to the file.
    if ($scheme == 'private') {
      if (file_exists($derivative_uri)) {
        return parent::download($request, $scheme);
      }
      else {
        $headers = $this
          ->moduleHandler()
          ->invokeAll('file_download', array(
          $image_uri,
        ));
        if (in_array(-1, $headers) || empty($headers)) {
          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.', array(
          '%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.
    $lock_name = 'image_style_deliver:' . $image_style
      ->id() . ':' . Crypt::hashBase64($image_uri);
    if (!file_exists($derivative_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) || $image_style
      ->createDerivative($image_uri, $derivative_uri);
    if (!empty($lock_acquired)) {
      $this->lock
        ->release($lock_name);
    }
    if ($success) {
      $image = $this->imageFactory
        ->get($derivative_uri);
      $uri = $image
        ->getSource();
      $headers += array(
        'Content-Type' => $image
          ->getMimeType(),
        'Content-Length' => $image
          ->getFileSize(),
      );

      // \Drupal\Core\EventSubscriber\FinishResponseSubscriber::onRespond()
      // sets response as not cacheable if the Cache-Control header is not
      // already modified. We pass in FALSE for non-private schemes for the
      // $public parameter to make sure we don't change the headers.
      return new BinaryFileResponse($uri, 200, $headers, $scheme !== 'private');
    }
    else {
      $this->logger
        ->notice('Unable to generate the derived image located at %path.', array(
        '%path' => $derivative_uri,
      ));
      return new Response($this
        ->t('Error generating image.'), 500);
    }
  }

}

Classes

Name	Description
ImageStyleDownloadController	Defines a controller to serve image styles.