Re: RDF Update Feeds + URI time travel on HTTP-level

On Mon, Nov 23, 2009 at 1:01 AM, Peter Ansell <ansell.peter@gmail.com> wrote:
> The issue with requiring people to direct requests at the URI for the
> Resource X at time T is that the circular linking issue I described
> previously comes into play because people need to pre-engineer their
> URI's to be compatible with a temporal dimension.

I would recommend the use of a query parameter.

> If the user didn't
> know exactly what time scales were used by the server they would
> either need to follow a roughly drawn up convention, such as
> /YYYY/MM/DD/meaningfulresourcename, or they would have to find an
> index somewhere, neither of which are as promising for the future of
> the web as having the ability to add another header to provide the
> desired behaviour IMO.

I'm not sure what criteria you're basing that evaluation on, but IME
it's far simpler to deploy a new relation type than a new HTTP header.
 Headers are largely opaque to Web developers.

> The documentation of the Vary header [1] seems to leave the situation
> open as to whether the server needs to be concerned about which or any
> Headers dictate which resource representation is to be returned.
> Caching in the context of HTTP/1.1 may have been designed to
> temporary, but I see no particular reason why a temporal Accept-*
> header, together with the possibility of its addition to Vary,
> couldn't be used on the absolute time dimension. It seems much cleaner
> than adding an extra command to HTTP, or requiring some other non-HTTP
> mechanism altogether. The extra header would never stop a server from
> returning the current version if it doesn't recognise the header, or
> it doesn't keep a version history, so it should be completely
> backwards compatible.

Yes, Vary should, in theory, be used for this purpose.  Unfortunately,
in practice, due to a bug in IE, it has the effect of disabling
caching in the browser and so you don't see it used very much, at
least not for browser based applications;

http://www.ilikespam.com/blog/internet-explorer-meets-the-vary-header

Mark.

Received on Monday, 23 November 2009 15:26:49 UTC