W3C home > Mailing lists > Public > public-ws-addressing@w3.org > December 2004

Re: i014 - Metadata Update/Reconciliation: a proposal

From: Doug Davis <dug@us.ibm.com>
Date: Wed, 15 Dec 2004 13:35:15 -0500
To: Hugo Haas <hugo@w3.org>
Cc: public-ws-addressing@w3.org
Message-ID: <OF9C93DB8E.E8E0EF98-ON85256F6B.0052EBC9-85256F6B.00661B1B@us.ibm.com>
I was thinking of the case of one service, one EPR (given to two different 
clients) but two WSDLs depending on the type of user.

Can you elaborate on your use-case (metadata caching purposes)?  If I'm 
guessing correctly I can see doing that on the server-side since it will 
probably know the full context - did you envision this being a 
server-side-only feature?  Would almost have to be, I think, since as we 
said there could lots be factors that could influence whether two EPR's 
metadata/WSDL... are the same.  But, if this really is only a server-side 
optimization then isn't that really an implementation choice/detail and 
not something that should be in the WSA spec (or even perhaps left for the 
WS-MDEX spec)?

hugo@w3.org wrote on 12/15/2004 09:55:29 AM:

> * Doug Davis <dug@us.ibm.com> [2004-12-15 08:57-0500]
> >   If two different client applications are given the same EPR (same 
> > address and ref.props) can we really assume they have the same 
> > metadata/wsdl.... ?
> It all comes down to how we define and use [address] and [reference
> properties], the properties we get from them being a function of the
> constraints they are placing on their use.
> Right now, they are defined as:
>   same [address]/[reference properties] ? same metadata
>   different [address]/[reference properties] ? same metadata
> With this definition, *if* you want to have different metadata, *then*
> you have to use a different [address]-[reference properties] pair. And
> if you do have identical pairs, then you can draw such a conclusion.
> > As an example, what if based on the client's permissions the WSDL
> > for a particular endpoint will differ - perhaps one has Admin access
> > and the other doesn't.  In this case can WSA really claim that the
> > two EPRs are the same w.r.t. metadata/WSDL and messages they accept?
> > No.
> [..]
> I think it depends on how the service is built and exposed.
> Two clients may be talking to the same service, with the same
> [address]/[reference properties]. One client may have access to more
> operations than the other, because it has different access privileges.
> The service is the same for both, except that the lower-privileged
> client is not authorized to use certain operations, and may not even
> be aware of them.
> So, in both cases, the WSDL is the same, it's just that one is
> authorized to do certain things and the other one isn't.
> Another way to do this would be to have two different, logically
> separate, interfaces, and use different [address]/[reference
> properties]. In this case, we have different metadata indeed.
> Cheers,
> Hugo
> -- 
> Hugo Haas - W3C
> mailto:hugo@w3.org - http://www.w3.org/People/Hugo/
> [attachment "signature.asc" deleted by Doug Davis/Raleigh/IBM] 
Received on Wednesday, 15 December 2004 18:35:49 UTC

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