title: Quickest way to get content type
body: <p>I need to chech for the content type (if it's image, audio or video) of an url which has been inserted by the user. I have a code like this:</p>
  
  <pre><code>URL url = new URL(urlname);
  URLConnection connection = url.openConnection();
  connection.connect();
  String contentType = connection.getContentType();
  </code></pre>
  
  <p>I'm getting the content type, but the problem is that it seems that it is necessary to download the whole file to check it's content type. So it last too much time when the file is quite big. I need to use it in a Google App Engine aplication so the requests are limited to 30 seconds.</p>
  
  <p>Is there any other way to get the content type of a url without downloading the file (so it could be done quicker)?</p>