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The HTTP 'link' and 'Content-Base' Headers

From: Ian Hickson <py8ieh@bath.ac.uk>
Date: Wed, 24 Mar 1999 18:28:42 GMT
To: http-wg@hplb.hpl.hp.com
Cc: connolly@w3.org, "L. David Baron" <dbaron@fas.harvard.edu>, James Clark <jjc@jclark.com>
Message-Id: <Pine.GSO.4.04.9903241750140.14284-100000@ss1.bath.ac.uk>


It has been brought to my attention that the HTTP 'Link' header has been
removed from the latest version of HTTP 1.1 (IETF's Internet Draft dated 
November 1998).

I understand that the reason for this change was that the HTTP WG
considered the semantics to have been poorly defined. For example, one
post on HTTP-wg says:

: There are known problems with some of the proposals: e.g. Link sytax
: does not quite seem to be what the HTML group needs for enabling 
: server setting of sytle sheets; its grammar is suspect. [1]

Could you please explain what is "not quite what the HTML group needs"
and why RFC 2068's definition of the grammar is 'suspect'?

NGLayout, the engine behind version 5 of Netscape's browser, currently
comprehensively supports the HTTP Link header, as defined in RFC 2068.
No particular difficulties in interpreting the semantics of the 'Link'
header were hit when working on getting this feature implemented.

This header is _incredibly_ useful, for, eg, setting the webmaster
email address of every document in a site or for changing the
stylesheet selected in every page of a 2000 document site, without
having to edit each file individually. (The "Default-Style" header is
very useful in this respect too.)

I have also noticed that the 'Content-Base' header was also deleted.
NGLayout also supports this HTTP header.

Your time is greatly appreciated.

-- References --
[1] quoted in:

Test cases exist for both of those headers at

NGLayout latest build is available from

Note that NGLayout currently only supports HTTP headers specified in
META elements. This is due to a bug that is preventing any HTTP header
from reaching the document's DOM, and will be fixed prior to release.

Ian Hickson 
U+2642 U+2651
U+262E U+2603 U+263A
Received on Monday, 29 March 1999 14:21:44 UTC

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