title: How to respond to an HTTP OPTIONS request?
body: <p>The HTTP <code>OPTIONS</code> method is supposedly used to determine what other methods the server supports on a given resource.  Given that, I have two questions:</p>
  <ul>
  <li><p>What does this response look like?  I have seen examples with CSV lists in <code>Public</code>, <code>Allow</code>, and even <code>Access-Control-Allow-Methods</code> headers.  Are they all needed?  What's the difference?  <a href="https://www.rfc-editor.org/rfc/rfc2616#section-9.2" rel="noreferrer">RFC 2616</a> doesn't seem to be very helpful here.</p>
  </li>
  <li><p>Would it be appropriate to use this to list the actions that a resource supports in a non-REST-API environment?  For example, if my <code>ConversionController</code> supports the action <code>convert</code>, would a response like this make sense:</p>
  </li>
  </ul>
  <p>Request:</p>
  <pre><code>OPTIONS /conversion HTTP/1.1
  </code></pre>
  <p>Response:</p>
  <pre><code>HTTP/1.1 200 OK
  ...
  Allow: CONVERT
  ...
  </code></pre>