title: How to download a file uploaded to a private Facebook group using Graph API
body: <p>Facebook now allows us to upload arbitrary types of files to Facebook groups, which is great. I am writing a single-sign-on iOS app, which accesses such a private group the user belongs to, and download those files. </p>
  
  <p>I was able to acquire the URL to those files using Graph API, which look like this:</p>
  
  <p><a href="http://www.facebook.com/download/444555666777888/foo.bar" rel="nofollow">http://www.facebook.com/download/444555666777888/foo.bar</a></p>
  
  <p>(If I type this URL to a browser, the browser downloads it as long as I have logged in to Facebook as me from that browser, but will fail otherwise -- Facebook has a good security feature). </p>
  
  <p>I can't pass this URL to graph API because it's not part of graph (which always starts with <a href="https://graph.facebook.com/" rel="nofollow">https://graph.facebook.com/</a>), but I can't download it using a regular NSURLConnection because of the lack of access token.</p>
  
  <p>Is there any proper way to download those files? Or, is there any particular HTTP header I need to set when downloading such a file using NSURLConnection? </p>