Re: Is This a Web Service?

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?