RE: Is This a Web Service?

MessageHow about this:

Web service = any application that communicates with other applications
using Web protocols. The service should provide some type of description of
its interface.

XML Web service = any application that communicates using an XML protocol
and secribes its interface using an XML-based description language.

W3C Web service = any application that communicates using SOAP and describes
itself using WSDL.
  -----Original Message-----
  From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]On
Behalf Of Cutler, Roger (RogerCutler)
  Sent: Tuesday, April 15, 2003 11:17 AM
  To: Walden Mathews; www-ws-arch@w3.org
  Subject: RE: Is This a Web Service?


  Is that serious?  Are you saying that if it doesn't use XML it's not a Web
service?  Do other people agree?

  My personal opinion, as I said, is that the described situation is,
indeed, a Web service because it communicates between two applications via
the Web.  I guess, intuitively, that's what I think a Web service
fundamentally is.  I would say, however, that it is a VERY primitive Web
service, and that to progress in sophistication and function you need to add
XML, SOAP, description (whether WSDL or TPP/TPA) and so on.

  -----Original Message-----
  From: Walden Mathews [mailto:waldenm@optonline.net]
  Sent: Monday, April 14, 2003 4:31 PM
  To: Cutler, Roger (RogerCutler); www-ws-arch@w3.org
  Subject: Re: Is This a Web Service?


  What?  A web service with no XML?  Surely this is treason.
  (Off with his header.;-)
    ----- Original Message -----
    From: Cutler, Roger (RogerCutler)
    To: www-ws-arch@w3.org
    Sent: Monday, April 14, 2003 5:19 PM
    Subject: Is This a Web Service?


    The recent conversation has included the interesting idea of looking at
Web services as SOAP services.  Are we really saying that SOAP is integral
and required for ALL Web services?  For example (and this is a real
example), suppose there is a Web site on the internet that is oriented
toward returning results to people on browsers, but if you set the
parameters of the GET in a particular manner it runs an application that
generates an image (the nature of which depends on other parameters) and
returns that image (and only the image) as an HTTP type image/png.  I now
have an application that at some point wants to make such an image with the
contents based, shall we say, on calculated values (in fact, this determines
text that is inside the image, if you must know) -- and I do a GET with the
appropriate parameters, wait for the HTTP to come back, write the binary
stream of the image somewhere and go about the business of the application
which does something with the image.

    Now, I personally think that's a Web service, mostly because of the
application to application flavor.  I would not call it a "W3C Web service",
since it doesn't use WSDL and SOAP -- but it seems pretty Web service-ey to
me.  I would personally call it an "ad hoc" Web service -- and I would make
up another name for ebXML transactions that use SOAP but not WSDL, since it
seems to me that those, too, are Web services that handle the description
differently.

    But what do you folks think?  Does it absolutely have to use SOAP to be
a Web service?  If so, that's an interesting and really useful thing to
know.  My personal opinion, for what it is worth, is that simpler, ad hoc
things like the example above are, indeed, Web services, but you quickly
start needing SOAP if you want to do anything other than the most basic
operations, and so in practice most of the "interesting" Web services use
SOAP.  I am certainly willing to agree that if a Web service uses ANY
enveloping mechanism that it should be SOAP, since there don't seem to be
any other real popular candidates.  Is that a reasonable point of view?