Handling files with Alice/HautelookAliceBundle

structure

DataFixtures
    ORM
        theme.yml
    Resources
        Theme
            1.jpg
            2.jpg

theme.yml

AppBundle\Entity\Theme:
    theme_1:
        background: '1.jpg'

ThemeProcessor.php

<?php

namespace AppBundle\DataFixtures\Processor;

use AppBundle\Entity\Theme;
use AppBundle\Entity\ThemeRepository;
use AppBundle\File\Theme\BackgroundFile;
use Nelmio\Alice\ProcessorInterface;
use Symfony\Component\HttpFoundation\File\UploadedFile;

class ThemeProcessor implements ProcessorInterface
{
    private $bgFileHandler;
    private $themeRepo;

    public function __construct(BackgroundFile $bgFileHandler, ThemeRepository $themeRepository)
    {
        $this->bgFileHandler = $bgFileHandler;
        $this->themeRepo = $themeRepository;
    }

    public function preProcess($object)
    {
    }

    public function postProcess($object)
    {
        if (!$object instanceof Theme) {
            return;
        }

        if ($object->getBackground()) {
            $filePath = __DIR__.'/../Resources/Theme/'.$object->getBackground();
            $object->setBackgroundFile(new UploadedFile(
                $filePath,
                $object->getBackground(),
                mime_content_type($filePath),
                filesize($filePath),
                null,
                true
            ));
            $this->bgFileHandler->upload($object);
            $this->themeRepo->save($object);
        }
    }
}