Casbah's GridFS upsert operation

PictureLoader.scala

private def upsert(filename: String, extension: String, is: InputStream) {
    gridfs.findOne(filename) match {
      case Some(_) => println(filename + " is already in database")
      case None =>
        gridfs(is) {
          file =>
            file.filename = filename
            file.contentType = "image/" + extension
        }
    }
  }