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Re: LC68 - Use-cases

From: Prasad Yendluri <pyendluri@webmethods.com>
Date: Mon, 27 Jun 2005 12:06:16 -0700
Message-ID: <42C04E28.7050502@webmethods.com>
To: Glen Daniels <gdaniels@sonicsoftware.com>
CC: public-ws-addressing@w3.org

Glen,

I agree that having a way to mark extensions mandatory (or fail) is 
useful (core issue of 68). However I consider the usecase #2 a red 
herring. How a URI in an EPR is mapped to a physical location is outside 
the scope for WS-A.

Regards, Prasad

Glen Daniels wrote:

>Hi folks:
>
>Here are a couple of scenarios which I think serve to illustrate issues
>around LC68, and why I believe we should introduce some kind of
>@wsa:mandatory attribute.
>
>In general, I also think the text in the last paragraph of section 2.5
>is problematic.  It seems like we're basically saying "sure, you can do
>anything with extensions but you had better not do anything that really
>changes anything since it can get ignored (despite us just having told
>you that you CAN really change things)".  Yuk.
>
>#1 - Policy
>
>According to the current core spec (section 2.5), any extension (which
>would include things like WS-Policy) that is not understood is freely
>ignorable, and "standard processing" will ensue in these cases.  This
>means that there is no way to express in an EPR the idea that "you MUST
>use WS-Security when talking to this endpoint".  Despite the fact that
>this concept is expressible in WSDL, and in Policy, the rules for EPR
>extensions do not provide a mechanism to indicate that a specific policy
>is mandatory.
>
>#2 - Directories
>
>We know <wsa:Address> values are logical, not physical, URIs (even
>though in most cases thus far they are exactly the same as the transport
>URI used to contact the endpoint).  Therefore, an EPR user may need to
>do some kind of mapping in order to figure out how to actually convert a
><wsa:Address> into something that can be used "on the wire".  We can
>posit an EPR extension which selects a particular directory service to
>be used with a particular EPR.  In this case, it is not possible that
>the EPR user will be able to "guess" what to do with the <wsa:Address>
>outside the context of the directory service, therefore marking the
>extension as mandatory is appropriate.
>
><wsa:EPR>
> <wsa:Address>myURI:Fred</wsa:Address>
> <ds:DirectoryService wsa:mandatory="true">
>   http://MinnesotaGreenPages.com/
> </ds:DirectoryService>
></wsa:EPR>
>
>Thanks,
>--Glen
>  
>
Received on Monday, 27 June 2005 19:06:33 GMT

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