title: How to get the Facebook user id using the access token
body: <p>I have a Facebook desktop application and am using the <a href="http://en.wikipedia.org/wiki/Facebook_Platform#Graph_API" rel="noreferrer">Graph API</a>.
  I am able to get the access token, but after that is done - I don't know how to get the user's ID.</p>
  
  <p>My flow is like this:  </p>
  
  <ol>
  <li><p>I send the user to <em><a href="https://graph.facebook.com/oauth/authorize" rel="noreferrer">https://graph.facebook.com/oauth/authorize</a></em> with all required extended permissions.</p></li>
  <li><p>In my redirect page I get the code from Facebook.</p></li>
  <li><p>Then I perform a HTTP request to <em>graph.facebook.com/oauth/access_token</em> with my API key and I get the access token in the response.</p></li>
  </ol>
  
  <p>From that point on I can't get the user ID.</p>
  
  <p>How can this problem be solved?</p>