On Oct 1, at the request of the WG, I requested opening of an issue
relating to canonical forms. The note is at [1], and we have indeed
opened issue 441 [2] (thank you Yves!) Here I provide my personal opinion
on this issue. The questions raised are:
> On the call, there was debate as to whether it would or
> would not be OK for the lexical form of an infoset item
> to change during transmission. One opinion expressed
> was: yes, no problem, c14n can be run on the sent or
> received infosets in any case where you really care.
> The converse opinion was: no, don't let it change,
> because the SOAP Rec requires that all bindings (MTOM
> or otherwise) transmit the Infoset with full fidelity.
> So, we need to discuss whether to indicate that only
> canonical forms can be optimized by MTOM.
My answer is:
* The SOAP Rec is unambiguous, to be a SOAP binding you must preserve the
Infoset, which means you must preserve the characters even if in
non-canonical form (especially since SOAP doesn't even know about types!)
If it's an integer, you must preserve leading zeros, and if it's
base64Binary you must preserve whitespace, etc.
* The MTOM optimization seems incapable of distinguishing more than one
lexical form for a value.
From these two points I conclude that MTOM can optimize at most one
lexical representation of each value.
> If yes, we need to decide whether to adopt the canonical
> form suggested in the errata to XML schema [1] or some
> other form.
Well, I can see the case for a form with no linebreaks at all, but on
balance I think it's best to use whatever the Schema WG defines as
canonical. So: "yes", use the canonical form as defined in the Schema
erratum.
Noah
[1] http://lists.w3.org/Archives/Public/xml-dist-app/2003Oct/0001.html
[2] http://www.w3.org/2000/xp/Group/xmlp-issues#x441
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