Hi Dave,
Mark,
The same concerns I raised in xmlp apply here. The slippery slope of
manifests appears. What about other namespaces and vocabularies? For
example, SOAP with my foo vocabulary using xml schema data types would be:
application/xml; xmlns="soapns" xmlns="foons" xmlns="datatypesns"
or perhaps
application/xml; xmlns="soapns foons datatypens"
This would have to duplicata all the xmlns decls in the document.
Does this make sense?
I understood the slippery slope argument around the "+xml" convention
because the syntax didn't (and couldn't) preclude other "+" things.
But "xmlns" would be restricted to a single URI value identifying
the root namespace.
Note that I'm not really sold on this myself, it just looks pretty. 8-)
An issue with it is that every tool I'm familiar with that enables an
app to be bound to a media type, doesn't permit me to bind different
apps to different parameter values of the same type. So for example;
application/xml; xmlns="http://www.w3.org/1999/xhtml";
and
application/xml; xmlns="http://www.w3.org/2001/12/soap-envelope";
would only be allowed to be dispatched to a generic XML processor
anyhow, who would then be tasked with further dispatch based on the
namespace. So the parameter doesn't add a lot of value in that case
beyond what would be possible with just "application/xml", except as
a quicker lookup mechanism, which itself comes at the cost of the
complexity of duplicating that information and handling additional
error cases.
I think the need for it (or not) would come mostly from the email
community, which I unfortunately don't have nearly enough knowledge
about.
The way I see it, media types are broken for multiple namespace'd xml
documents, especially documents that are targetted to be frameworks like
soap. The "+" syntax for media-types simply doesn't scale to these kinds of
documents. I don't know how, but we have to find someway of either
expressing a manifest, or the name of a profile that is a reference to a
manifest. At least with the use of xmlns we have some notion of versions as
well, given the namespace name would be used.
I agree that media types aren't suitable for multi-namespaced documents.
That's why I'm all for making the transition from media types to
namespaces with either vanilla "application/xml", or adorned with the
root namespace.
MB
--
Mark Baker, Chief Science Officer, Planetfred, Inc.
Ottawa, Ontario, CANADA. mbaker(_at_)planetfred(_dot_)com
http://www.markbaker.ca http://www.planetfred.com