function remote_stream_wrapper_image_style_deliver in Remote Stream Wrapper 7
Copy of image_style_deliver() for use with remote images.
1 string reference to 'remote_stream_wrapper_image_style_deliver'
- remote_stream_wrapper_menu in ./
remote_stream_wrapper.module - Implements hook_menu().
File
- ./
remote_stream_wrapper.image.inc, line 6
Code
function remote_stream_wrapper_image_style_deliver($style, $scheme) {
$args = func_get_args();
array_shift($args);
array_shift($args);
$target = implode('/', $args);
// 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_allow_insecure_derivatives'
// variable 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 derivative is requested.)
$valid = !empty($style) && file_stream_wrapper_valid_scheme($scheme);
if (!variable_get('image_allow_insecure_derivatives', FALSE) || strpos(ltrim($target, '\\/'), 'styles/') === 0) {
$valid = $valid && isset($_GET[IMAGE_DERIVATIVE_TOKEN]) && $_GET[IMAGE_DERIVATIVE_TOKEN] === image_style_path_token($style['name'], $scheme . '://' . $target);
}
if (!$valid) {
return MENU_ACCESS_DENIED;
}
$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 (!file_exists($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.
$success = file_exists($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();
}
}