FOAF link in request headers

From: Danny Ayers <>
Date: Mon, 29 Aug 2005 14:36:12 +0200

Hi folks,

An idea I think may have legs is for agents (especially browsers) to
supply, in the HTTP request header, the URI of the FOAF profile of the
user of the browser.

The purpose, aside from passing a bit more RDF around, would be for
the server that receives such a header to customise the representation
returned according to any preferences expressed in the FOAF - a
specific use case being to provide targetted adverts.

When I posted about using cookies for this purpose, Brian (?)
suggested doing it the header - much neater, IMHO (although the
cookies approach may still have its uses).

There's the shiny commercial use case of more targetted ads, but
stepping back from that it has the potential to provide more
meaningful interactions between site and visitor. Shoot me now - I'm
starting to sound like someone from sales. But I do think it could be
fun, providing individual-customised interfaces to server-side
triplestore setups. At worst it's a low-cost experiment.

But there is a big issue outstanding, how to implement the HTTP header
extension in a WebArch-friendly fashion. I've stuck this on my blog,
and I'd be very grateful for any suggestions - the choices seem to be:

1. use "FOAF:"
- pursue IETF/IANA registration for it (see RFC 3864 and:

2. use "X-FOAF:"
- I've not found confirmation, but people seem to think it's ok
without registration

3. use (something like) "Profile:"
- it's not tied to a particular data type, might be more appropriate
and actually stand a chance of successful registration

4. use "Link: <>; rel="foaf"
- suggested by Mark Nottingham (editor/author of some of the related
specs) - it was in RFC 2068, (but isn't in 2616), so should be
acceptable standards-wise, has the advantage of mapping 1:1 with HTML
link tag. Christopher Schmidt recognised the Link: construct, posted
some further references to #swig:

So...any preferences?
(I'd be willing to do the paperwork if registration was needed)

More notes, and even a little code (!) around:

Graham Klyne's behind the registry docs (along with mnot), as one
would expect he's done some RDF noodling with it:


Received on Mon Aug 29 2005 - 12:32:11 EDT

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