/**
* Using the configured image identifier generator, attempt to generate a unique image
* identifier for the given image until we either have found a unique ID or we hit the maximum
* allowed attempts.
*
* @param EventInterface $event The current event
* @param Image $image The event to generate the image identifier for
* @return string
* @throws ImageException
*/
private function generateImageIdentifier(EventInterface $event, Image $image)
{
$database = $event->getDatabase();
$config = $event->getConfig();
$user = $event->getRequest()->getUser();
$imageIdentifierGenerator = $config['imageIdentifierGenerator'];
if (is_callable($imageIdentifierGenerator) && !$imageIdentifierGenerator instanceof GeneratorInterface) {
$imageIdentifierGenerator = $imageIdentifierGenerator();
}
if ($imageIdentifierGenerator->isDeterministic()) {
return $imageIdentifierGenerator->generate($image);
}
// Continue generating image identifiers until we get one that does not already exist
$maxAttempts = 100;
$attempts = 0;
do {
$imageIdentifier = $imageIdentifierGenerator->generate($image);
$attempts++;
} while ($attempts < $maxAttempts && $database->imageExists($user, $imageIdentifier));
// Did we reach our max attempts limit?
if ($attempts === $maxAttempts) {
$e = new ImageException('Failed to generate unique image identifier', 503);
$e->setImboErrorCode(Exception::IMAGE_IDENTIFIER_GENERATION_FAILED);
// Tell the client it's OK to retry later
$event->getResponse()->headers->set('Retry-After', 1);
throw $e;
}
return $imageIdentifier;
}