title: Download link (via API) to publicly accessible file on google docs returns 401
body: <p>I've uploaded a (pgp) file via the documents API, and changed its
  visibility to public. However, I'm unable to download it publicly
  using the contents link for that file.</p>
  
  <p>Here are the relevant bits of the xml for the meta-data for the file in
  question.</p>
  
  <pre><code>$ curl -H "GData-Version: 3.0" -H "Authorization: Bearer ..." https://docs.google.com/feeds/default/private/full
  
  ...
      &lt;content type="application/pgp-encrypted" src="https://doc-0c-c0-docs.googleusercontent.com/docs/securesc/tkl8gnmcm9fhm6fec3160bcgajgf0i18/opa6m1tmj5cufpvrj89bv4dt0q6696a4/1336514400000/04627947781497054983/04627947781497054983/0B_-KWHz80dDXZ2dYdEZ0dGw3akE?h=16653014193614665626&amp;amp;e=download&amp;amp;gd=true"/&gt;
  ...
      &lt;gd:feedLink rel="http://schemas.google.com/acl/2007#accessControlList" href="https://docs.google.com/feeds/default/private/full/file%3A0B_-KWHz80dDXZ2dYdEZ0dGw3akE/acl"/&gt;
  
  $ curl -H "GData-Version: 3.0" -H "Authorization: Bearer ..." https://docs.google.com/feeds/default/private/full/file%3A0B_-KWHz80dDXZ2dYdEZ0dGw3akE/acl
  
  ...
    &lt;entry gd:etag="W/&amp;quot;DUcNRns4eCt7ImA9WhVVFUw.&amp;quot;"&gt;
      &lt;id&gt;https://docs.google.com/feeds/id/file%3A0B_-KWHz80dDXZ2dYdEZ0dGw3akE/acl/default&lt;/id&gt;
  ...
      &lt;gAcl:role value="reader"/&gt;
      &lt;gAcl:scope type="default"/&gt;
  ...
  </code></pre>
  
  <p>The role/scope returned for the file in question is <code>reader/default</code>, indicating
  it is public. (It also shows up with public shared access in the web UI.)</p>
  
  <p>However, accessing
  the src attribute in the content element results in:</p>
  
  <pre><code>$ curl --verbose 'https://doc-0c-c0-docs.googleusercontent.com/docs/securesc/tkl8gnmcm9fhm6fec3160bcgajgf0i18/opa6m1tmj5cufpvrj89bv4dt0q6696a4/1336514400000/04627947781497054983/04627947781497054983/0B_-KWHz80dDXZ2dYdEZ0dGw3akE?h=16653014193614665626&amp;e=download&amp;gd=true'
  
  &lt; HTTP/1.1 401 Unauthorized
  &lt; Server: HTTP Upload Server Built on May 7 2012 18:16:42 (1336439802)
  &lt; WWW-Authenticate: GoogleLogin realm="http://www.google.com/accounts"
  &lt; Date: Tue, 08 May 2012 22:48:37 GMT
  &lt; Expires: Tue, 08 May 2012 22:48:37 GMT
  &lt; Cache-Control: private, max-age=0
  &lt; Content-Length: 0
  &lt; Content-Type: text/html
  </code></pre>