Re: Some proposed definitions of "web service" based on the call toda y

Christopher,

Would you want to include SOAP-based RPC in that first paragraph,
or is it better to leave it out?  Or is it implied by the broader "exchange
of SOAP messages"?

Walden
  ----- Original Message ----- 
  From: Christopher B Ferris 
  To: www-ws-arch@w3.org 
  Sent: Friday, April 18, 2003 8:00 AM
  Subject: Re: Some proposed definitions of "web service" based on the call toda y



  I would prefer that we not include references to version numbers in the definition, as these will 
  change over time. I think that the acronyms should suffice. Secondly, I thinn that qualifying SOAP by 
  calling out the XML Infoset and processing model suggests that other aspects of SOAP are either 
  not used, or not allowed, or who knows what. I think that it is sufficient to say just SOAP. Finally, since 
  we have spent some time discussing the various types of ways in which people have been using the term, 
  I felt that it is probably worthwhile that we share some of these alternate uses with the readers of the 
  WSA and give them a little more background. 

  How 'bout this: 
  ------------------------------------------------------------------------- 
  The term "Web service" has been used to refer to a wide variety of things, 
  and it is clear that not all people share the same understanding and definition. 
  For some, it has meant simply the exchange of XML over the Web, typically using HTTP. 
  For others, it has meant simply the exchange of SOAP messages, typically using HTTP, 
  or some software component that has been described using WSDL. In a sense, all of these 
  things might be considered to be "Web services", and the Working Group does not 
  preclude the use of the term to describe these sorts of things. Nevertheless, for 
  the purposes of this document, we will define the term Web services as follows: 

  [Definition: Web service - an executable software agent that is identified by 
  a URI and whose interface and binding(s) are described using WSDL. Other software agents 
  interact with a Web service in a manner prescribed by its WSDL description, using SOAP.] 

  --------------------------------------------------------------------------------------------------------------------------------------------------- 

  Now, this definition probably deserves some further explanation in order to say things like  "there's nothing 
  to preclude the use of other protocols (than SOAP) to interact with a Web service... for the purposes of this document, we simply 
  aren't going to go there" and "while the definition requires the use of WSDL, it does not preclude the use of 
  other technologies or XML vocabularies for its description. however, for the purposes of this document, we 
  aren't going to go there..." 

  Again, it might be nice to solve the equation for all possible solutions to WS = U + Xd + Xm (a web service is identified 
  by a URI and described using XML and interacted with using XML messages) IMO this represents a daunting 
  task. We should be focused on defining an architecture that leverages the technologies being developed 
  in our sibling WGs in the Web Services Activity in its realization. 

  Cheers, 

  Christopher Ferris
  Architect, Emerging e-business Industry Architecture
  email: chrisfer@us.ibm.com
  phone: +1 508 234 3624 

  www-ws-arch-request@w3.org wrote on 04/17/2003 05:36:27 PM:

  > 
  > Whew, that was fun :-(  Although it got better when we stumbled on the
  > "instant straw poll in IRC" idea; we should do that more often.  I'd say
  > that in general, anyone who has the "floor" in the speaker queue may propose
  > one of those by typing the question into IRC; those not on IRC can ask to
  > have their vote recorded by someone who is.
  > 
  > Let me throw out some proposals that reflect the various opinions I heard
  > today; without my co-chair hat on, I could live with either of them:
  > 
  > ===========================================================================
  > The term "web service" is used in a wide variety of ways by different
  > people, and we will not presume that the definition used here is consistent
  > with all of them.  Nevertheless, for the purposes of this document, we will
  > use the term to mean the following: A Web service is [an interface to ?] an
  > executable software agent that is designed to be used by another software
  > agent.  A Web service is
  > identified by a URI, and MUST be [capable of being ?] formally defined in
  > WSDL 1.2.  A software agent interacts with an  Web service in the manner
  > prescribed by the formal definition, using the XML Infoset and processing
  > model defined by SOAP 1.2.
  > 
  > [Chris said some things about SOAP being general enough to describe any
  > reasonable "web service" interaction that I didn't capture very well ...
  > maybe he can refresh my memory.]
  > 
  > ==========================================================================
  > 
  > The term "web service" is used in a wide variety of ways by different
  > people, but there is a rough consensus along the following lines: A Web
  > service is an interface to an executable software agent that is designed to
  > be used by another software agent.  A Web service is identified by a URI,
  > and has a definition in a language sufficient to describe the interface to
  > developers of client agents. A software agent interacts with a Web service
  > in the manner that is consistent with the description, using standard
  > protocols. 
  > 
  > That definition of "web service" is not sufficiently precise or rigorous for
  > architectural purposes, however.  We will use a more restrictive term to
  > describe the scope of the architecture described here: "Extensible XML Web
  > Services", abbreviated XWS.   the purposes of this document, we will use the
  > term to mean the following: An XWS is an interface to an executable software
  > agent that is designed to be used by another software agent.  An XWS is
  > identified by a URI, and MUST be capable of being formally defined in WSDL
  > 1.2.  A software agent interacts with an  Web service in the manner
  > prescribed by the formal definition, using the XML Infoset and processing
  > model defined by SOAP 1.2."
  > 
  > ["XWS" is essentially a placeholder for some term ... I don't care what it
  > is, but it must specifically describe the "MUST" constraints specified by
  > the WSA.]
  > 
  > ==========================================================================
  > Of course, improved definitions are solicited.
  >