Custom namer oneuploadBundle Symfony

Question

I'm trying to use dropzone with 1up-lab/OneupUploaderBundle. Upload is working well, and I'm trying to use my custom namer. My configuration:

oneup_uploader:
    mappings:
        products:
            namer: app.upload_namer
            use_orphanage: true
            frontend: dropzone
            storage:
                directory: "%kernel.root_dir%/../data/products/"

Service conf

app.upload_namer:
    class: AppBundle\Uploader\Naming\UploadNamer
    arguments: ["@security.token_storage"]

My Namer:

class UploadNamer implements NamerInterface
{

    private $tokenStorage;
    private $productName;

    public function __construct(TokenStorage $tokenStorage){
        $this->tokenStorage = $tokenStorage;
    }

    /**
     * Creates a user directory name for the file being uploaded.
     *
     * @param FileInterface $file
     * @return string The directory name.
     */
    public function name(FileInterface $file)
    {
        $userName = $this->tokenStorage->getToken()->getUser();

        return sprintf('%s/%s.%s',
            $userName,
            uniqid(),
            $file->getExtension()
        );
    }

}

I need to pass a folder name ($productName) to my namer, so I can use it to create storage folder:

 products/$userName/$productName/$filename.ext

This variable will come from my form:

formData.append("productName", "loremipsum");

How can I can retrieve this parameter from my Namer ?

Thank you!