Re: Question on section 2.7.1, Part 1

Nilo Mitra asks:

>> I wonder if the MAY in the last quoted part is valid for the case of a 
>> SOAP header block with a role attribute of "next". Surely for such 
>> blocks, the header block MUST be reinserted, whether this block is 
>> processed or ignored. In fact, shouldn't something be mandated 
>> regards forwarding for header blocks with a role="next"?

Actually, no.  In general, the rule is that whether to reinsert is 
determined when you understand and choose to process the header. 

Now, I actually do think there is an issue here.  It's one that some of us 
have been discussing privately, sort of deciding whether to raise it as an 
issue.  I've owed a few people including Mark Jones, David Fallside, and 
Henrik a decision on whether I want to pursue it.  Basically:  the 
question arises, what happens if a non mU header addressed to next is not 
understood at some intermediary stop.  The draft rec is clear that it 
disappears from the relayed message, for the reason you question above. It 
could not possibly be processed, since it's not understood;  it doesn't 
have to be processed, because it's not mU;  it is definitely removed 
(except on the off chance that processing of some other feature causes it 
to stay) because it's addressed to the node and not processed.

The potential question is:  what if I want to create a header with the 
following characteristics:

        * it can be processed at any node.
        * the default is that it not disappear (as you essentially propose 
above)

I think it is nearly essential that this be possible.  There are several 
ways one might imagine getting it.  Some clearly would change our rec. For 
example, I've always found the "remove and reinsert" rule unduly tricky 
and would be just as happy to have a default that says "leave it if you 
don't process it."  Another change to the rec would be a controlling 
attribute soapenv:removeIfNotProcessd, or some such.  I think I've 
understood Henrik to say in private conversation:  "if you make up your 
own role name and send to that, you essentially have permission to change 
the processing rules on this for the role", essentially because if you 
don't know what the role is, you don't play it, and the header will 
survive.

I'm sort of torn about whether I think Henrik's approach is the right one. 
 Add to that a real reluctance to raise formally any issues unless 
something is truly and provably broken, and I've been dragging my feet. 
about this. 

So, this same analysis should probably go on distApp, but as I say, I've 
been holding off until I can figure out whether I should say "this is 
broken and needs fixing" vs.  "we noticed this but we think it's OK." 
Advice and help most welcome.

Having said all of that, I think the status quo is clear, and it's that 
you remove the header if it's targeted to you (including next), and 
reinserted only if some explicit processing has that result.
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Noah Mendelsohn                              Voice: 1-617-693-4036
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"Nilo Mitra (EUS)" <Nilo.Mitra@am1.ericsson.se>
10/04/02 03:47 PM

 
        To:     "'Martin Gudgin'" <mgudgin@microsoft.com>, "Nilo Mitra (EUS)" 
<Nilo.Mitra@am1.ericsson.se>, Jean-Jacques Moreau <moreau@crf.canon.fr>, 
Marc Hadley <marc.hadley@sun.com>, Noah Mendelson 
<noah_mendelsohn@us.ibm.com>, Henrik Frystyk Nielsen 
<henrikn@microsoft.com>
        cc:     W3C Public Archive <www-archive@w3.org>
        Subject:        Question on section 2.7.1, Part 1
Categories: 
 




Dear Editors: 
While attempting to put in some text on forwarding intermediaries in the 
Primer, I took a look at Section2.7.1, Part 1 [1],
and have a question about some aspects of the text there: 
Para 2 says: "....They MUST also remove from the SOAP message all SOAP 
header blocks targeted at themselves, prior to forwarding, regardless of 
whether these header blocks were processed or ignored."
Para 3 says: "....Such rules MAY describe placement of inserted or 
reinserted SOAP header blocks. ...." 
I wonder if the MAY in the last quoted part is valid for the case of a 
SOAP header block with a role attribute of "next". Surely for such blocks, 
the header block MUST be reinserted, whether this block is processed or 
ignored. In fact, shouldn't something be mandated regards forwarding for 
header blocks with a role="next"?
Please could someone clarify. 
Thanks, 
Nilo 
[1] http://www.w3.org/2000/xp/Group/2/06/LC/soap12-part1.html#forwardinter

Received on Friday, 4 October 2002 18:18:13 UTC