Club Drupal

<?php

/**

 * Copy of image_style_deliver() for use with remote images.

 */

function remote_stream_wrapper_image_style_deliver($style, $scheme) {

  $args = func_get_args();

  array_shift($args);

  array_shift($args);

  $target = implode('/', $args);

  $image_uri = $scheme . '://' . $target;

  $derivative_uri = remote_stream_wrapper_image_style_path($style['name'], $image_uri);

  // Prevent only the remote files that exist in {file_managed} from having

  // image style derivatives generated. Otherwise this could open up the site

  // to allowing any remote file to be processed.

  if (!remote_stream_wrapper_file_load_by_uri($image_uri)) {

    return MENU_ACCESS_DENIED;

  }

  // 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:' . $style['name'] . ':' . drupal_hash_base64($image_uri);

  if (!is_file($derivative_uri)) {

    $lock_acquired = lock_acquire($lock_name);

    if (!$lock_acquired) {

      // Tell client to retry again in 3 seconds. Currently no browsers are known

      // to support Retry-After.

      drupal_add_http_header('Status', '503 Service Unavailable');

      drupal_add_http_header('Retry-After', 3);

      print t('Image generation in progress. Try again shortly.');

      drupal_exit();

    }

  }

  // Try to generate the image, unless another thread just did it while we were

  // acquiring the lock.

  $success = is_file($derivative_uri) || image_style_create_derivative($style, $image_uri, $derivative_uri);

  if (!empty($lock_acquired)) {

    lock_release($lock_name);

  }

  if ($success) {

    $image = image_load($derivative_uri);

    file_transfer($image->source, array('Content-Type' => $image->info['mime_type'], 'Content-Length' => $image->info['file_size']));

  }

  else {

    watchdog('image', 'Unable to generate the derived image located at %path.', array('%path' => $derivative_uri));

    drupal_add_http_header('Status', '500 Internal Server Error');

    print t('Error generating image.');

    drupal_exit();

  }

}