diff core/modules/image/src/Controller/ImageStyleDownloadController.php @ 0:c75dbcec494b

Initial commit from drush-created site

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/modules/image/src/Controller/ImageStyleDownloadController.php	Thu Jul 05 14:24:15 2018 +0000
@@ -0,0 +1,186 @@
+<?php
+
+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 Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpFoundation\BinaryFileResponse;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+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.
+   */
+  public function __construct(LockBackendInterface $lock, ImageFactory $image_factory) {
+    $this->lock = $lock;
+    $this->imageFactory = $image_factory;
+    $this->logger = $this->getLogger('image');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('lock'),
+      $container->get('image.factory')
+    );
+  }
+
+  /**
+   * 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\NotFoundHttpException
+   *   Thrown when the file request is invalid.
+   * @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) {
+      // Return a 404 (Page Not Found) rather than a 403 (Access Denied) as the
+      // image token is for DDoS protection rather than access checking. 404s
+      // are more likely to be cached (e.g. at a proxy) which enhances
+      // protection from DDoS.
+      throw new NotFoundHttpException();
+    }
+
+    $derivative_uri = $image_style->buildUri($image_uri);
+    $headers = [];
+
+    // If using the private scheme, let other modules provide headers and
+    // control access to the file.
+    if ($scheme == 'private') {
+      $headers = $this->moduleHandler()->invokeAll('file_download', [$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.', ['%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 = '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) || $image_style->createDerivative($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 += [
+        '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.', ['%path' => $derivative_uri]);
+      return new Response($this->t('Error generating image.'), 500);
+    }
+  }
+
+}