title: Check if NSURL is an Asset
body: <p>I have a NSURL class member wich can point to a <strong>local file</strong>, to a <strong>URL</strong> or to an <strong>Asset</strong>. I've found out that I have to use the Asset Library to load an Asset instead of:</p>
  
  <pre><code>[NSData dataWithContentsOfURL:nsurl];
  </code></pre>
  
  <p>So my Question is: <strong>How can I check if my NSURL object points to an Asset?</strong></p>
  
  <p>I've tried the search, but I've only how to check if it's a local file :(</p>
  
  <p>PS: My App has to be iOS4 compatible</p>