title: CodeIgniter -> Get current URL relative to base url
body: <p>Tried <a href="http://codeigniter.com/user_guide/libraries/uri.html" rel="noreferrer"><code>URI::uri_string()</code></a> but can't get it to work with the base_url.</p>
  
  <p>URL: <code>http://localhost/dropbox/derrek/shopredux/ahahaha/hihihi</code><br>
  Returns: <code>dropbox/derrek/shopredux/ahahaha/hihihi</code></p>
  
  <p>but <code>http://localhost/dropbox/derrek/shopredux/</code> just returns an empty string.</p>
  
  <p>I want the first call to return "ahahaha/hihihi" and the second to return "". Is there such a function?</p>