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customMediaType-2 : charset in RFC 3023

From: Chris Lilley <chris@w3.org>
Date: Mon, 29 Jul 2002 22:18:58 +0200
Message-ID: <48248968.20020729221858@w3.org>
To: www-tag@w3.org

Hello ,

This ammendment regarding charset in RFC 3023 closes my action item to
post it to the public list.

Current text:

<p>The first example in the preceding section is a particularly
troublesome case. RFC 3023 gives rules for when the charset parameter
SHOULD be used, and states that it is always authoritative. However, a
receiving application can, with very high reliability, determine the
encoding of an XML document by reading it, without reference to any
external headers. The consequence is that server-side applications
SHOULD ensure that for XML representations, they supply a charset
header only where there is complete certainty as to the encoding in
use, since an error will cause a perfectly usable representation to be
rejected by an architecturally sound client.</p>


Change to:

<p>The first example in the preceding section is a particularly
troublesome case. RFC 3023 states in section 7.1</p>

<blockquote>The use of the charset parameter is STRONGLY RECOMMENDED,
since this information can be used by XML processors to determine
authoritatively the charset of the XML MIME entity.
</blockquote>

<p>and states that when used it is always authoritative. However, a
receiving application can, with very high reliability, determine the
encoding of an XML document by reading it, without reference to any
external headers and this is reflected by RFC 3023 in sections 8.9
Application/xml with Omitted Charset and UTF-16 XML MIME Entity, 8.10
Application/xml with Omitted Charset and UTF-8 Entity, and 8.11
Application/xml with Omitted Charset and Internal Encoding
Declaration.</p>

<p>Thus there is no ambiguity when the charset is omitted, and the
STRONGLY RECOMMENDED injunction to use the charset is misplaced for
application/xml and for non-text "+xml" types. The consequence is
that</p>

<ul>

<li><p> server-side applications SHOULD ensure that for XML
representations, they supply a charset header only where there is
complete certainty as to the encoding in use, since an error will
cause a perfectly usable representation to be rejected by an
architecturally sound client.</p></li>

<li><p>the wording in section 7.1 should be ammeded to something like
the following</p> <blockquote>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.</blockquote></li>

</ul>
  

-- 
 Chris                          mailto:chris@w3.org
Received on Monday, 29 July 2002 16:20:15 GMT

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