W3C home > Mailing lists > Public > xml-dist-app@w3.org > January 2002

Re: Media type encoding parameter?

From: Jacek Kopecky <jacek@systinet.com>
Date: Thu, 3 Jan 2002 11:40:25 +0100 (CET)
To: Mark Baker <distobj@ACM.ORG>
Message-ID: <Pine.LNX.4.33.0201031127570.13354-100000@mail.idoox.com>
 see my responses below, I've removed the stuff I'm not
responding to.

                   Jacek Kopecky

                   Senior Architect, Systinet (formerly Idoox)

 > >  OK, the namespace of the root element might be useful for fast
 > > dispatch, in case of SOAP the "intent" of the message can be also
 > > useful for that purpose, also I'm nervous about that, but the
 > > encodingStyle is not a thing the server dispatches on.
 > That isn't a requirement of a media type parameter.  "charset" is also
 > not used to dispatch.

 I'm not sure here, but I think the charset may not be indicated
by the XML document itself and it must be known somehow. Anyway,
the charset (in the extreme) is necessary before even parsing the
text because in a strange charset the angle brackets can be
something completely other than ASCII angle bracket
representation. So without this knowledge you wouldn't even be
able to read the XML.
 On the other hand namespaces or any other XML information from
the document is always in the document.

 > It is good practice to provide, as metadata separate from the message
 > itself, any information that impacts a processor's ability to
 > successfully process the message.  This helps performance for sure
 > (though not in dispatch, but in preventing messages from being
 > processed when it is known that there's no point), but it's more a
 > statement about interoperability.

 If I take your words literally, you again want every bit of the
message outside of the envelope, for generally every bit of the
message can affect success or failure of processing.
 So I think you meant to say "...any reasonable and prudent
information that impacts..." and now we could argue about what's
reasonable and prudent outside of the envelope. I say, for SOAP,
nuffin'. If we were talking about a parameter of a type
application/xml, that would be different, for the root namespace
could be useful indeed.

 > So re the envelope, I'm suggesting an optional parameter of "envelope"
 > whose value would be an envelope URI.
 > And re the encoding, I'd like to know more about its common use.
 > If it were most commonly used on the envelope/header/body, and
 > there was normally only one, then I'd be tempted to create the
 > parameter.  If not, then I'd leave it.

Even though, AFAIK, encodingStyle is commonly used on the body
and there is usually only one, I dislike the trouble we'd get
into in trying to handle the unusual and uncommon cases. Once
there is only one something, like the root namespace of an XML
document, I'm OK with optionally indicating it outside of the
envelope, too, but again, for a generic MIME type, not for

Received on Thursday, 3 January 2002 05:41:06 UTC

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