Re: Responses to Tantek Çelik issues raised during third last call of UAAG 1.0

From: "Ian B. Jacobs" <ij@w3.org>
Cc: w3c-wai-ua@w3.org
Date: Mon, Jul 9, 2001, 5:25 AM

>> > ------------------------------------------------------------------
>> > Issue 489: Does "document source" include HTTP headers?
>> > http://server.rehab.uiuc.edu/ua-issues/issues-linear-lc3.html#489
>> > ------------------------------------------------------------------
>> >
>> > Resolution: The UAWG defines the term "document source" to be the
>> > payload of a request for a resource (and thus it excludes HTTP
>> > headers, for example). However, document source is prior to
>> > repair, as the definitions indicate:
>> >
>> >  <BLOCKQUOTE>
>> >  In this document, the term "document source" refers to the data that
>> >  the user agent receives as the direct result of a request for a Web
>> >  resource (e.g., as the result of an HTTP/1.1 [RFC2616] "GET", or as
>> >  the result of viewing a resource on the local file system). The
>> >  document source generally refers to the "payload" of the user agent's
>> >  request, and doesn't generally include information exchanged as part
>> >  of the transfer protocol. The document source is data that is prior
>> >  to any repair by the user agent (e.g., prior to repairing invalid
>> >  markup). "Text source" refers to document source that is composed of
>> >  text.
>> >  </BLOCKQUOTE>
>>
>> This is reasonable enough.  But, in this case, what about alternate (or
>> primary) style sheets which are specified through HTTP LINK headers?  The
>> above definition would seem to imply that they are not part of the "document
>> source".  This seems contrary to intent.
>
> IJ: I agree, as we would like to have access to these alternate style
> sheets and expect to for LINK elements. The "good news" (and I learned
> this by surprise some time ago) is that the Link header field is not
> part of HTTP/1.1. Refer to section 19.6.3 [1]:
>
>    "The Alternates, Content-Version, Derived-From, Link, URI, Public and
>     Content-Base header fields were defined in previous versions of
>     this specification, but not commonly implemented. See RFC 2068
> [33]."
>
> There's no link header in section 14 ("Header Field Definitions").
>
> [1] http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.6.3

Good to know.  HTTP LINK headers were but one example of HTTP headers which
affect the content, or the display thereof.

Another example is the HTTP Content-Language header, as this is often used
to denote the natural language of a document, using a language code (e.g.
"en-us"), which may then be utilized by :lang() selectors (<eg> :lang("en")
{ color:green } </eg>) in style sheets referenced by the document.  Access
to such style rules may require the presence of that portion of the HTTP
header.  Lack of that header may result in being denied access to such
styling.

Tantek

Received on Monday, 9 July 2001 15:36:53 UTC