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Re: Describing which blobs are to be optimized.

From: Prasad Yendluri <pyendluri@webmethods.com>
Date: Fri, 04 Jun 2004 17:27:03 -0700
Message-ID: <40C11357.3040804@webmethods.com>
To: Marc Hadley <Marc.Hadley@Sun.COM>
Cc: Jonathan Marsh <jmarsh@microsoft.com>, www-ws-desc@w3.org, xml-dist-app@w3.org

Since it is the server that is marking this optional, my interpretation 
would be that the server prefers to send and receive optimized 
serializations but the client is not required oblige it. If the client 
does not initiate with an optimized serialization then the server SHOULD 
not use the optimization. I agree the semantics of "optional" nature of 
this feature need to be captured properly.

Regards, Prasad

Marc Hadley wrote:

> On a related note I'm unclear on the semantics implied by marking the 
> MTOM/XOP feature as optional. I can see several interpretations:
>
> (i) a service will never use it but a client may
> (ii) a service will not use it unless client does first
> (iii) a service will always use it but a client isn't obliged to
>
> Marc.
>
> On Jun 4, 2004, at 2:27 PM, Jonathan Marsh wrote:
>
>> The WS Description WG is working through an issue (#207 [1]), which is
>> XOP-related.  As we communicated to you earlier [2], the ability of a
>> service to accept and transmit XOP can be indicated by indicating the
>> HTTP Transmission Optimization Feature is in use through the WSDL
>> feature syntax.  This syntax also allows the MTOM feature to be
>> "required", which we interpret as, the service must be sent a XOP
>> envelope and media type, though XOP itself doesn't constrain which parts
>> of the XML within that envelope have been optimized (it could be none).
>>
>> A question arises ([3] continuing on [4]) that if XOP is required,
>> whether it further makes sense to say precisely which parts of the
>> message are to be optimized.  As we understand it, this allows a service
>> to place additional restrictions on the use of XOP beyond what the XOP
>> spec describes, but not leaving it completely up to the application
>> layer.  These additional restrictions could be along the lines of
>> "anything marked with an expectedMediaType attribute must be optimized",
>> to a fine level of granularity through an xop:optimize="true" attribute
>> on the schema.
>>
>> The working group has a preference (straw poll 7 to 4 [5]) to indicate
>> in some fashion which parts must be optimized.  However, since you own
>> the HTTP Transmission Optimization Feature, we wanted to ask you two
>> questions:
>>
>> 1) Do you feel that such descriptive hints would be useful or is it
>> contrary to the expected usage patterns of XOP?
>> 2) If it is useful, would you be willing to describe these hints,
>> including introducing syntax, in the MTOM or XOP specs?  (Splitting a
>> feature and it's descriptive hints across multiple specs seems
>> suboptimal to us.)
>>
>> [1] http://www.w3.org/2002/ws/desc/2/06/issues.html#x207
>> [2] http://lists.w3.org/Archives/Public/www-ws-desc/2004May/0077.html
>> [3] http://lists.w3.org/Archives/Public/www-ws-desc/2004May/0089.html
>> [4] http://lists.w3.org/Archives/Public/www-ws-desc/2004Jun/0000.html
>> [5] http://lists.w3.org/Archives/Public/www-ws-desc/2004Jun/0019.html
>>
> ---
> Marc Hadley <marc.hadley at sun.com>
> Web Products, Technologies and Standards, Sun Microsystems.
Received on Friday, 4 June 2004 20:27:43 GMT

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