At 19:15 03/12/18 +0100, Max Froumentin wrote:
Linus Walleij <triad(_at_)df(_dot_)lth(_dot_)se> wrote:
> OK so then I regard this as official W3.org policy on transport type.
I expect that that policy would rather be set by the TAG. See:
http://www.w3.org/2001/tag/2002/0129-mime
"Thus there is no ambiguity when the charset is omitted, and the
STRONGLY RECOMMENDED injunction [in RFC3023] to use the charset is
misplaced for application/xml and for non-text "+xml"
types.
I agree that we should change the 'strongly recommended' to a
more balanced wording and a more detailed discussion in
the upcomming RFC 3023 update.
I also just found out that there are apparently two findings
dealing with the above issue, the other one (still at draft
stage) at http://www.w3.org/2001/tag/doc/mime-respect-20031210.html
(diff at
http://www.w3.org/2001/tag/doc/mime-respect-20031210-diff.html).
Consequently, for XML representations, server-side applications
SHOULD only supply a charset header when there is complete certainty
as to the encoding in use. Otherwise, an error will cause a perfectly
usable representation to be rejected by an architecturally sound
client."
I think that this is basically right, but highly overstated.
There are two points:
1) It implies that leaving off the charset parameter will always
lead to perfectly correct documents.
While there are certain cases where indeed leaving out the
charset parameter will improve things, when the charset
parameter is wrong, there are also cases where things will
get worse, and there are cases where things are not affected.
2) The language used seems to be inappropriate for a specification,
because specifications in general assume that people do what
the spec says. If we would fill up our specs with notes saying
that you shouldn't do this if you don't get it right, our specs
would all be much longer and much more difficult to read.
In addition, note that the finding you cited continues as follows:
>>>>>>>>
We recommend that section 7.1 of [RFC3023] be amended to something like the
following:
The use of the charset parameter, when the charset is reliably known
and agrees with the encoding declaration, is RECOMMENDED, since this
information can be used by non-XML processors to determine authoritatively
the charset of the XML MIME entity.
>>>>>>>>
So it does not look to me that the TAG is recommending to remove
the charset parameter from application/foo+xml registrations.
Regards, Martin.