Re: Until HTTP header when the representation will disappear in the future

[Amos Jeffries <[e-mail]>]

On 12/06/2013 5:45 p.m., Karl Dubost wrote:
> Hi,
>
> I was wondering if people had already imagined a mechanism to warn about the decay, or the non persistence of a URI. No bikeshed yet about the name let's call it "zardoz" instead of "Valid-until".
>
> Let's say a document will be obsolete for legal reasons, contests, sunsetting Web sites or APIs, etc. after midnight on June 24 and I want to say to user agent that it will be 410 Gone after this date and/or a temporary redirect will be finished at a precise date (maintenance for example).
>
>
> → http HEAD http://example.org/
>
> HTTP/1.1 200 OK
> Accept-Ranges: bytes
> Cache-Control: max-age=600
> Content-Length: 34322
> Content-Type: text/html; charset=utf-8
> Date: Wed, 12 Jun 2013 05:36:14 GMT
> Last-Modified: Tue, 11 Jun 2013 21:57:50 GMT
> Zardoz: Wed, 24 Jun 2013 23:59:59 GMT
>
>
> Is there already a way to do this that I would have missed.
> The semantics of Expire is not exactly the same.

A combination of Expires (and/or max-age=N) and 
Cache-Control:must-revalidate serve this purpose.

eg, whatever content was delivered becomes stale at timestamp Z and the 
origin MUST be consulted befoe any further use of it past that time.

Amos