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Re: R: potential users of web services

From: David Martin <martin@AI.SRI.COM>
Date: Mon, 08 Apr 2002 10:54:20 -0700
Message-ID: <3CB1D94C.EB68203E@ai.sri.com>
To: Pierluigi Plebani <gigi.plebani@tin.it>
CC: www-ws@w3.org
We shouldn't be too hasty to try to pin down some specific number of players in the Web service
picture.  For one thing, t's not hard to imagine a service that is offered collaboratively by 2 or
more providers.  For example, in purchasing something you sometimes deal with one provider who
provides the product and another who provides a financing arrangement.

I think the dynamic nature of the Web, and the technologies we are working on, could make such
multiparty arrangements even more common on the Web than they are in offline transactions.

Of course, one can argue that all multiparty transactions can be built up from 2-party services, and
that may well be true.  I'm just saying that there needs to be a place in our representational
universe where the multiparty transactions can be described.

Regards,

David Martin
SRI International


Pierluigi Plebani wrote:

> Hi all,
>
> I'm an Italian Ph.D. Student interested in the Web Service technology, and
> the first issue encountered in my research activity is: "What is a Web
> Service?"
> I read all your proposals and, more or less, I think all are correct. Now I
> would propose my definition of Web Service in order to contribute to the
> maiing list and also obtain some suggestions.
> My definition has been developed starting from the SOA (Service Oriented
> Architecture) definition. This context sees three players (the service
> requestor, the service provider and the service directory) interacting among
> them, by using three primitives (publish, find, bind). Any information
> exchange is based on a common medium transport.
> Starting from that, in my opinion:
>
> "A Web Service architecture is a SOA instance where the considered transport
> medium is the Web; thus a Web Service is an autonomous component handled by
> the three players".
>
> On the basis of this definition, a Web Service:
> - does not need to be necessary described through XML;
> - does not need to use SOAP as a transport-protocol;
> - does not need to use UDDI for the registry operation;
> - ...
>
> Conversely, only the Web and its protocols (such as IP-TCP-HTTP-...), are
> necessary.
> That's my view over Web Services. Hope somebody of you agree...
> Any suggestion is of course welcome.
>
> Gigi
>
> > -----Messaggio originale-----
> > Da: www-ws-request@w3.org [mailto:www-ws-request@w3.org]Per conto di
> > Allan Doyle
> > Inviato: venerdi 5 aprile 2002 16.18
> > A: www-ws@w3.org
> > Oggetto: RE: potential users of web services
> >
> >
> > I've been following this thread with interest. I was doing a
> > presentation on Web Services for some people I work for and one of the
> > things I had to do was define what a Web Service is. I took the easy
> > way out and said that some people think it has to be fully buzzword
> > compliant and others think that any machine-to-machine interaction
> > over the internet is a Web Service. It's clearly a term that has
> > fallen into the hands and imaginations of the marketing departments.
> >
> > On Friday 2002-04-05 at 15:33:24(+1000) Hao He wrote:
> >  >
> >  > >"Web Services, the session told us, are not necessarily in
> > XML and do not
> >  > have to use SOAP, they just >describe opening up your internal
> > processes."
> >  >
> >  > I would agree with this statement in principal but not in
> > practise. As you
> >  > pointed out, it is essentially important for web services to be loosely
> >  > coupled.  For that reason, it is really difficult not to use XML for
> >  > messaging if soneone does not want to reinvent the wheel.
> >
> > Within the OGC, we developed a service known as "WMS" (Web Map
> > Service [1][2]). It fully specs out the format of an HTTP GET
> > request and you
> > get back a rendered map as a JPEG, PNG, etc. XML is used so the client
> > can ask the server what kinds of maps it can produce. But the requests
> > are done with GET. (HTTP POST of XML encodings of the request have
> > been proposed). The interface follows REST [3] principles (although we did
> > not know that at the time).
> >
> > I would say that a service followig REST principles even if it does
> > not use XML in the request or the response still counts as a web
> > service.
> >
> >       Allan
> >
> > [1] http://www.opengis.org/techno/specs/01-068r3.pdf
> > [2] http://www.intl-interfaces.net/cookbook/WMS/
> > [3] http://internet.conveyor.com/RESTwiki/moin.cgi
> >
> >
> >  >
> >  > As to SOAP, it has a strong "RPC" style although the later
> > version is moving
> >  > away from it, which is a good thing.  So SOAP is not really
> > required. BTW, I
> >  > just received Anne's email and I agree with her again!
> >  >
> >  > Hao
> >  >
> >  >
> >  > -------------------------------------------------
> >  >
> >  >
> >  > Seems to me that SOAP and XML are pretty required to be called a Web
> >  > service. Otherwise, it's a distributed app, but not the new
> > loosly coupled
> >  > thing we are all working on.
> >  >
> >  > Thanks,
> >  > Keith
> >  >
> >  > [1] http://www.webservicesarchitect.com/content/articles/wiggers03.asp
> >  >
> >  >    -----Original Message-----
> >  >    From: Anne Thomas Manes [mailto:anne@manes.net]
> >  >    Sent: Thursday, April 04, 2002 5:48 PM
> >  >    To: Hao He; thomi@di.uoa.gr; www-ws@w3.org
> >  >    Subject: RE: potential users of web services
> >  >
> >  >    +1
> >  >
> >  >    I was struggling with that word. I was originally going to call it
> >  > simply
> >  >    software -- trying not to  imply any level of granularity, but then
> >  > I
> >  >    thought -- well, it might actually be implemented using firmware or
> >  >    hardware. So I went with the word component. Perhaps it might be
> >  > best to
> >  >    call it a unit of work (although I don't want to imply that it
> >  > supports
> >  >    transaction semantics).
> >  >
> >  >    Anne
> >  >
> >  >    > -----Original Message-----
> >  >    > From: www-ws-request@w3.org [mailto:www-ws-request@w3.org]On
> >  > Behalf Of
> >  >    > Hao He
> >  >    > Sent: Thursday, April 04, 2002 7:35 PM
> >  >    > To: 'Anne Thomas Manes'; thomi@di.uoa.gr; www-ws@w3.org
> >  >    > Subject: RE: potential users of web services
> >  >    >
> >  >    >
> >  >    > I agree most with Anne except one tiny bit:
> >  >    >
> >  >    > I would say that a web service is a service provided by one or
> >  > more
> >  >    > components that exposes
> >  >    > a programmatic interface.  A compoent itself is not the service.
> >  >    > Service is
> >  >    > the functionality that defined in the interface.
> >  >    >
> >  >    >
> >  >    > Hao
> >  >    >
> >  >    > -----Original Message-----
> >  >    > From: Anne Thomas Manes [mailto:anne@manes.net]
> >  >    > Sent: Friday, April 05, 2002 5:05 AM
> >  >    > To: thomi@di.uoa.gr; www-ws@w3.org
> >  >    > Subject: RE: potential users of web services
> >  >    >
> >  >    >
> >  >    > Thomi,
> >  >    >
> >  >    > Ask five people the definition of "web service" and you'll get
> >  >    > six answers.
> >  >    >
> >  >    > I generally describe a web service as a service that communicates
> >  > over the
> >  >    > web. A service is a component that exposes a programmatic
> >  > interface. The
> >  >    > service interface must be described; and the service
> >  >    > implementation must be
> >  >    > discoverable.
> >  >    >
> >  >    > When you relate this abstract definition to current technologies,
> >  > you can
> >  >    > implement a web service by creating a service that exposes a SOAP
> >  >    > interface,
> >  >    > which is described by WSDL, and which is registered in UDDI. But
> >  >    > I wouldn't
> >  >    > want to use current technologies to *define* the basic concept. I
> >  >    > also don't
> >  >    > think that it's essential to use any of these technologies to
> >  > create a web
> >  >    > service. I can certainly create a web service using XML-RPC or
> >  >    > RosettaNet or
> >  >    > a host of other technologies.
> >  >    >
> >  >    > That said, I would concur that web services are intended to be
> >  > consumed by
> >  >    > applications rather than humans. But keep in mind that a user
> >  > interface is
> >  >    > an application. If I wanted to arrange food for 500 people for
> >  >    > two weeks in
> >  >    > Dubai, I would use a catering application, which in turn uses web
> >  > services
> >  >    > to find caterers that can provide services in Dubai. The UI isn't
> >  > the web
> >  >    > service. The UI uses web services to accomplish its work. Hence
> >  >    > an ASP page
> >  >    > or HTML form aren't web services, they are an interface to web
> >  > services.
> >  >    >
> >  >    > Best regards,
> >  >    >
> >  >    > Anne Thomas Manes
> >  >    > CTO, Systinet
> >  >    >
> >  >    > > -----Original Message-----
> >  >    > > From: www-ws-request@w3.org [mailto:www-ws-request@w3.org]On
> >  >    > > Behalf Of Thomi Pilioura
> >  >    > > Sent: Thursday, April 04, 2002 9:09 AM
> >  >    > > To: www-ws@w3.org
> >  >    > > Subject: potential users of web services
> >  >    > >
> >  >    > >
> >  >    > > Hi all,
> >  >    > >
> >  >    > > I'm little confused about the notion of the term "web services".
> >  >
> >  >    > > When I'm reading papers related to UDDI,WSDL,SOAP they present
> >  >    > > web services
> >  >    > > as a new age of distributed computing and as such they are only
> >  >    > useful to
> >  >    > > developers (who are trying to build web applicattions) and not
> >  > to the
> >  >    > > end-users. But when I'm reading papers related to DAML-S the
> >  > idea I'm
> >  >    > > getting for web services is different. They are also useful to
> >  >    > > end users as
> >  >    > > it shown by DAML-S motivating scenarios:
> >  >    > >
> >  >    > > Web service discovery
> >  >    > > Find me a shipping service that transports goods to Dubai.
> >  >    > >
> >  >    > > Web service invocation
> >  >    > > Buy me 500 lbs. powdered milk from www.acmemoo.com
> >  >    > >
> >  >    > > Web service selection, composition and interoperation
> >  >    > > Arrange food for 500 people for 2 weeks in Dubai.
> >  >    > >
> >  >    > > Web service execution monitoring
> >  >    > > Has the powdered milk been ordered and paid for yet?
> >  >    > >
> >  >    > > There are also numerous papers that use the term service (and
> >  > not "web
> >  >    > > service") and are talking about UDDI, WSDL and DAML-S. What's
> >  > the
> >  >    > > difference
> >  >    > > between "web service" and "service" if both of them work over
> >  >    > > Internet? For
> >  >    > > example, a search engine (such as google) is a service, but when
> >  > it is
> >  >    > > described in WSDL, published in UDDI and can be invoked using
> >  >    > > SOAP becomes a
> >  >    > > web service? Ia a asp or an HTML form a service or a web
> >  > service?
> >  >    > >
> >  >    > > In summary which are the potential users of web services (web
> >  > service
> >  >    > > providers, developers, end-users)?
> >  >    > >
> >  >    > > could you please shed some light on this?
> >  >    > > regards
> >  >    > > Thomi Pilioura
> >  >    > >
> >  >    > >
> >  >    > >
> >  >    > >
> >  >    >
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> > --
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Allan Doyle                         http://www.intl-interfaces.com
> > adoyle@intl-interfaces.com
> >
> >
> >
Received on Monday, 8 April 2002 13:50:54 GMT

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