return when {
      file.name.endsWith(".css") -> "text/css"
      file.name.endsWith(".gif") -> "image/gif"
      file.name.endsWith(".html") -> "text/html"
      file.name.endsWith(".jpeg") -> "image/jpeg"
      file.name.endsWith(".jpg") -> "image/jpeg"
      file.name.endsWith(".js") -> "application/javascript"
      file.name.endsWith(".png") -> "image/png"
      else -> "text/plain"
    }
  }

  companion object {