title: More capable alternative to XMLHttpRequest available for Firefox add-ons?
body: <p>I am currently writing an add-on for Firefox that uses <code>XMLHttpRequest</code> to send some HTTP requests to a remote server. However, I have run into the following limitations:</p>
  
  <ul>
  <li><code>XMLHttpRequest</code> transparently follows HTTP 3xx redirects (which is undesired)</li>
  <li><code>XMLHttpReques</code>t ignores <code>setRequestHeader</code> for certain headers (such as <code>User-Agent</code>)</li>
  <li>HTTP Basic Authentication is also handled by the browser - prompting the user for credentials with no way to disable this behavior</li>
  </ul>
  
  <p>For these reasons (and possibly others), I am looking for an alternative means to send HTTP requests from within a Firefox add-on. I've looked around MDN quite a bit but haven't come across anything that seems to meet my needs.</p>
  
  <p>Does such a class exist?</p>
  
  <p><strong>Note:</strong> I am not using the SDK.</p>