title: HTTP Accept-Encoding and sending unencoded data
body: <p>I building a module for compressing HTTP output. Reading the <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html" rel="noreferrer">spec</a>, I haven't found a clear distinction on a couple of things:</p>
  
  <p><code>Accept-Encoding:</code></p>
  
  <p><strong>Should this be treated the same as a <code>Accept-Encoding: *</code> or as if no header is present?</strong></p>
  
  <p>Or what if I don't support gzip, but I get a header like this:</p>
  
  <p><code>Accept-Encoding: gzip</code></p>
  
  <p><strong>Should I return a 406 error or just return the data unencoded?</strong></p>
  
  <p>EDIT:</p>
  
  <p>I've read over the spec a few times. It mentions my first case, but it doesn't define what the behavior of the server should be.</p>
  
  <p>Should I treat this case as if the header is not present? Or should I return a 406 error  because there's no way to encode something given the field value ('' isn't a valid encoding).</p>