title: How to determine the file extension of a file from a URL (Objective-C)
body: <p>I have a URL of type: <a href="http://example.com/files/" rel="nofollow">http://example.com/files/</a>
  And I need to determine what file is there (extension and name of file). Depending on extensions, I'll do something. 
  How can I determine it?</p>