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RE: Some text that may be useful for the update of RFC 2376



>-----Original Message-----
>From: Martin J. Duerst [mailto:duerst@xxxxxx]
>Sent: Wednesday, March 15, 2000 6:17 AM
>Subject: Re: Some text that may be useful for the update of RFC 2376
>
> [snip]
>I completely disagree. A trancoder transcodes. A transcoder may know
>about a few (or a lot of) encodings. It is absolutely unreasonable
>to ask for a transcoder to know all kinds of data formats, and
>where in that data format some encoding hints are hidden (if they are).

I agree that transcoders
- are a good thing
- have to be able to do their job without interpreting the data

But there is an open issue with XML (media type "text/xml") via HTTP:

There are systems out there now (e.g. IE5, Netscape 4.7) that send
XML documents with correct encoding declaration as media type "text/xml"
without charset parameter.
If the document arrives without a charset parameter in the Content-Type
header at the XML processor's site, the processor does not know whether
there was a transcoder involved or not and has to use encoding "us-ascii"
for this document.

The XML spec (chapter 4.3.3 Character Encoding in Entities,
(http://www.w3.org/TR/REC-xml.html#charencoding), says:
   "In the absence of information provided by an external transport protocol
    (e.g. HTTP or MIME), it is an  error for an entity including an encoding
    declaration to be presented to the XML processor in an encoding other
than
    that named in the declaration, ..." 

Unfortunately this "absence of information provided by an external transport
protocol" can never happen with the current definition of media type
"text/xml"
since RFC 2376 requires the fallback to the default "us-ascii".

I think the charset parameter should stay "STRONGLY RECOMMENDED" and
authoritative, but if there is no charset parameter given, the encoding 
declaration of the XML document should be used.


All the best,
Paul

-------------------------------------------------------------
Paul Langer               E-mail   Paul.Langer@xxxxxxxxxxxxxx
Software AG               Tel.     +49-6151-92-1912
Uhlandstr. 12             Fax      +49-6151-92-1613
64297 Darmstadt




-------------------------------------------------------------
Paul Langer               E-mail   Paul.Langer@xxxxxxxxxxxxxx
Software AG               Tel.     +49-6151-92-1912
Uhlandstr. 12             Fax      +49-6151-92-1613
64297 Darmstadt