Uploaded filename sanitizer for Bolt (updated)

UploadSanitizerProvider.php

<?php
namespace Bolt\Provider;

use Cocur\Slugify\Slugify;
use Silex\Application;
use Silex\ServiceProviderInterface;

class SanitizerProvider implements ServiceProviderInterface
{
    protected $replacement;

    /**
     * {@inheritdoc}
     */
    public function register(Application $app)
    {
      
        $app['upload.sanitizer'] = $app->share(function ($app)
        {
            $pattern     = $app['config']->get('general/upload/pattern', '[^A-Za-z0-9\.]+');
            $lowercase   = $app['config']->get('general/upload/lowercase', true);

            $regexp = "/$pattern/";

            /** @var Slugify $sanitizer */
            $sanitizer = new Slugify($regexp, ['lowercase' => $lowercase]);

            return $sanitizer;
        });

        $app['upload.sanitizer.replacement'] = $app->share(function ($app)
        {
            $replacement = $app['config']->get('general/upload/replacement', '-');
            return $replacement;
        });


        $app['upload'] = $app->share(
            $app->extend(
                'upload',
                function (\Sirius\Upload\Handler $uploadHandler) use ($app) 
                {
                    $uploadHandler->setSanitizerCallback(
                        function ($filename)  use ($app) {
                            $cleanName = $app['upload.sanitizer']->slugify($filename, $app['upload.sanitizer.replacement']);
                            return $cleanName;
                        }
                    );

                    return $uploadHandler;
                }
            )
        );
    }

    /**
     * {@inheritdoc}
     */
    public function boot(Application $app)
    {
    }
}