Re: Caching Question re Paging

On Mon, Apr 13, 2015 at 7:40 AM, Eric Prud'hommeaux <eric@w3.org> wrote:

> * Robert Sanderson <azaroth42@gmail.com> [2015-04-08 15:23-0700]
> > Am I missing something obvious that makes all of this null and void and
> > it's already been discussed and discarded as unnecessary?
>
> Only tangentially. The 2nd to last paragraph of RFC 7240 "Prefer
> Header for HTTP" says that
> [[
>                              If a server supports the optional
>    application of a preference that might result in a variance to a
>    cache's handling of a response entity, a Vary header field MUST be
>    included in the response listing the Prefer header field regardless
>    of whether the client actually used Prefer in the request.
> ]]
> so technically we're all set. That said, it might be nice to mention
> that to the reader. Can you propose and editorial change?
>


Yes, I didn't think it meant a normative change (reading the minutes of the
call this morning, apologies for missing it).

How about a paragraph at the end of 6.1 along the lines of:

----

<p>
In order to allow the web infrastructure to correctly cache the responses
of an LDP Paging server, the requirements of the current HTTP [rfc2616] and
Prefer Header [rfc7240] specifications should be kept in mind.  Notably,
RFC7240 requires conforming implementations to return a <code>Vary</code>
header that includes <code>Prefer</code> in its value.  As an LDP server
must also support negotiation for the content format using the
<code>Accept</code> request header, the resulting response will include at
least:
</p>

<pre class="example">
Vary: Accept, Prefer
</pre>

----

(This of course also applies to LDP proper, but that ship has sailed)

Rob

-- 
Rob Sanderson
Information Standards Advocate
Digital Library Systems and Services
Stanford, CA 94305