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Re: Definition for a Web Service

From: Anne Thomas Manes <anne@manes.net>
Date: Mon, 11 Aug 2003 18:33:57 -0400
Message-ID: <001b01c36058$ad4bf250$7501a8c0@TPX21>
To: "Cutler, Roger \(RogerCutler\)" <RogerCutler@chevrontexaco.com>
Cc: "Www-Ws-Arch@W3. Org" <www-ws-arch@w3.org>

I'm not completely up to date on all the latest musings within WS-Desc, but
I don't believe they equate a service with an endpoint. A service may offer
multiple ports, and each port has a separate endpoint.

As long as a service has only one endpoint, then it's reasonable to use the
endpoint URL to name the service. But if the service has multiple endpoints,
which endpoint do you use as the service URI?

Based on the last set of questions they asked me about the issue, I think
you're right -- I think that they decided that the wsdl:service Qname names
the service, and if you want a URI to name the service then you should
derive one from the Qname. I'm not especially happy with this decision, but
I can live with it.

If that is the decision, then WS-Arch can claim that the service is
identified by a URI derived from the wsdl:service Qname.

Anne

----- Original Message -----
From: "Cutler, Roger (RogerCutler)" <RogerCutler@chevrontexaco.com>
To: "Anne Thomas Manes" <anne@manes.net>
Sent: Monday, August 11, 2003 6:06 PM
Subject: RE: Definition for a Web Service


> I don't understand how what you say below goes together with your answer
> to Frank, in which you say that the URI should name the service, not the
> endpoint.  But my understanding has been that the WS-Desc WG is
> identifying the service with the endpoint.  I am confused, but I think
> that the understanding in the WSA-WG is that we are trying to arrange
> our terminology and concepts so that our "service" is at least close to
> the same thing as a WS-Desc service -- that is, I thought, an endpoint.
> But, as I said, I'm confused.
>
> I am pretty sure, however, that the TLA URI was deleted from the WS
> definition in a discussion where the word Qname came up.
>
> -----Original Message-----
> From: Anne Thomas Manes [mailto:anne@manes.net]
> Sent: Monday, August 11, 2003 4:53 PM
> To: Cutler, Roger (RogerCutler); Jean-Jacques Moreau; Www-Ws-Arch@W3.
> Org
> Subject: Re: Definition for a Web Service
>
>
> Personally, I agree with the decision that a Web service must be
> described by WSDL. :-) But that doesn't mean that it won't also be
> described by other description languages. And as you say, that's beside
> the point.
>
> I'm not convinced that the discussion is completely closed in WS-Desc,
> and I think that if WS-Arch suggests that naming the service with a URI
> would be a good idea, the WS-Desc team would be happy to consider the
> input.
>
> Anne
>
> ----- Original Message -----
> From: "Cutler, Roger (RogerCutler)" <RogerCutler@chevrontexaco.com>
> To: "Anne Thomas Manes" <anne@manes.net>; "Jean-Jacques Moreau"
> <jean-jacques.moreau@crf.canon.fr>; <www-ws-arch@w3.org>
> Sent: Monday, August 11, 2003 3:42 PM
> Subject: RE: Definition for a Web Service
>
>
> >
> > We have -- and I personally think that this is unfortunate but it does
>
> > represent a clear, consensus-driven decision by the WG that I accept,
> > albeit reluctantly -- limited the scope of what we are willing to call
>
> > Web services and discuss in our architecture to thingies that are
> > described by WSDL and use SOAP -- as you can see in the definition.
> > That is, as far as we are concerned thingies described (only) by text
> > documents or DAML (unless DAML is somehow integrated into WSDL, which
> > I understand may not be an unreasonable expectation) are not Web
> > services. This was a highly contentious issue and the resolution of it
>
> > was so difficult that I think it would take some sort of dramatic
> > change in the situation to convince people in the WG to reopen it.  As
>
> > I said, I don't like this resolution, but I would like reopening the
> > issue a WHOLE LOT LESS!
> >
> > That was not, however, the thrust of your message.  I personally agree
>
> > that Web services are "important" resources and, for that reason,
> > should be identified by a URI.  I do not know how many others on the
> > WG would also agree, but I would guess at least some.  Or at least
> > would agree that "it sure would be nice" if Web services were
> > identified by a URI.
> >
> > It is my perception that the WG is, in effect, unwilling to do things
> > that are not compatible with what the WS-Desc WG is doing/has done,
> > and is also unwilling to tell the WS-Desc WG what to do.  I would be
> > very surprised, however, if anyone on the WSA-WG would actually object
>
> > violently if the WS-Desc WG were somehow to decide to use URI's to
> > identify Web services.
> >
> > Obviously the comments above are my personal take on the situation ...
>
> > Another member of the WG might view things quite differently and I am
> > in no way a spokesman for the WG.
> >
> > -----Original Message-----
> > From: Anne Thomas Manes [mailto:anne@manes.net]
> > Sent: Monday, August 11, 2003 1:02 PM
> > To: Cutler, Roger (RogerCutler); Jean-Jacques Moreau;
> > www-ws-arch@w3.org
> > Subject: Re: Definition for a Web Service
> >
> >
> > I raised a discussion on the WS-Desc list suggesting that they really
> > should identify a Web service by a URI rather than just a Qname. I was
>
> > a little surprised by the resistence to such a concept. I got the
> > sense that a lot of people didn't understand what in fact the URI was
> > meant to identify.
> >
> > I don't know what the end decision on the discussion was. I believe it
>
> > was discussed at the last meeting.
> >
> > But I do think that the architecture group should have some influence
> > on the discussion. If the architecture group believes that a Web
> > service should be named by a URI, then the WS-Desc team should provide
>
> > a means to capture that name in the WSDL description.
> >
> > From my perspective, a Web service is an "important" resource, and as
> > the Web Architecture says, all "important" resources should have a
> > URI. I also expect that a Web service may be described by a variety of
>
> > description languages (WSDL, DAML, text documents, etc.) and so there
> > ought to be a means of referring to the Web service that doesn't
> > depend on just one description language (a URI derived from the
> > wsdl:service Qname).
> >
> > Anne
> >
> > ----- Original Message -----
> > From: "Cutler, Roger (RogerCutler)" <RogerCutler@chevrontexaco.com>
> > To: "Jean-Jacques Moreau" <jean-jacques.moreau@crf.canon.fr>;
> > <www-ws-arch@w3.org>
> > Sent: Monday, August 11, 2003 10:47 AM
> > Subject: RE: Definition for a Web Service
> >
> >
> > >
> > > I think that this happened because of all the confusion about URI's
> > > and QNames.  As I understand it (and I am very willing to admit that
>
> > > I
> >
> > > understand this imperfectly), just about everyone concerned would be
>
> > > VERY happy to say that Web services are identified by URI's --
> > > except that currently in WSDL they are identified by a Qname --
> > > which is not exactly a URI but can be mapped to a URI.  This, at the
>
> > > least, adds a layer of confusion to any conversation on this
> > > subject.  I think that the basic thinking was that the "Web-related
> > > standards" would lead one
> >
> > > sort of inevitably to URI's, and that the detailed issues could be
> > > dealt with ... in the detailed sections, I guess.
> > >
> > > -----Original Message-----
> > > From: Jean-Jacques Moreau [mailto:jean-jacques.moreau@crf.canon.fr]
> > > Sent: Monday, August 11, 2003 3:45 AM
> > > To: www-ws-arch@w3.org
> > > Subject: Definition for a Web Service
> > >
> > >
> > >
> > > Thanks for the new draft; obviously, this is the result of a lot of
> > > efforts!
> > >
> > > Regarding the new definition for a Web Service: apart from being
> > > more specific (WSDL, SOAP, HTTP), which I like, the other major
> > > difference seems to be that a Web Service is no longer identified by
>
> > > a URI. Is this
> > >
> > > intentional? Shouldn't this be added back?
> > >
> > > <previousDefinition>
> > > A Web service is a software system identified by a URI [...].
> > > </previousDefinition>
> > >
> > > Comments?
> > >
> > > Jean-Jacques.
> > >
> > > Champion, Mike wrote:
> > >
> > > > Update from the W3C publication team:
> > > >
> > > > New WD of "Web Services Architecture" Document is available at :
> > > > http://www.w3.org/TR/2003/WD-ws-arch-20030808/
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
>
>
>
>
>
Received on Monday, 11 August 2003 18:40:11 GMT

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