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Re: Proposed issue; Visibility of Web services

From: Allan Doyle <adoyle@intl-interfaces.com>
Date: Fri, 30 May 2003 17:20:23 -0400
Message-ID: <16087.51991.906475.563620@intl-interfaces.com>
To: www-ws@w3.org

My understanding of REST is that anything after the GET that requires "out of
band" knowledge about the resource you're sending the GET to reduces
the visibility.

For example, if I build a stock quote service that takes requests of
the form

  http://my-service.com/quote.cgi?ticker=IBM

it's more opaque than a similar service where the form is

  http://my-service.com/quote/IBM

In order to be properly RESTful, the latter should appear as a link
in some other document so that it can be reached via a transition
from a previous representation.

If you look at some of Paul Prescod's writing about UDDI, for
example, he describes this quite nicely.

 http://webservices.xml.com/pub/a/ws/2002/02/06/rest.html
 http://www.google.com/search?q=prescod+uddi

Getting back to the example at hand, it's not the fact that SOAP was
used to encode the query that made it opaque. It's the fact that the
query had to be so complex at all.

      Allan

On Friday, May 30 2003 at 16:22:24(-0400) Christopher B Ferris wrote:
 > 
 > Mark,
 > 
 > Nonsense! It is just a parameter to the query that is an HTTP GET. It is 
 > NO
 > different than if there were a query parameter that took values of 
 > "chocolate"
 > or "vanilla" and dispatched that to separate functions for processing 
 > depending
 > on the value. It is still a GET. 
 > 
 > There is nothing in HTTP or REST that says HOW you implement the software 
 > that
 > sits behind the GET interface or how your URI is resolved or HOW the 
 > resource 
 > representation that is returned comes into being. 
 > 
 > If the GET is "safe", how the interface is implemented in software that 
 > processes
 > the method (GET) and its arguments (the URI, HTTP header fields and query 
 > arguments) 
 > is IRRELEVANT (by design no less!) no matter how ridiculously fine a 
 > distinction you seem 
 > to want it to place on it.
 > 
 > Cheers,
 > 
 > Christopher Ferris
 > STSM, Emerging e-business Industry Architecture
 > email: chrisfer@us.ibm.com
 > phone: +1 508 234 3624
 > 
 > www-ws-request@w3.org wrote on 05/30/2003 03:30:11 PM:
 > 
 > > 
 > > Jeff,
 > > 
 > > It's difficult to answer the visibility question for this example,
 > > because what you propose is to encode a message into an identifier.  As
 > > the message has a method ("GetStockPrice") and GET is also a method,
 > > there exists an ambiguity about what the effective method is, which is
 > > critical in determining the visibility.
 > > 
 > > Thanks.
 > > 
 > > MB
 > > -- 
 > > Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca
 > > Web architecture consulting, technical reports, evaluation & analysis
 > >   Actively seeking contract work or employment
 > > 
 > 

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allan Doyle                         http://www.intl-interfaces.com
+1.781.433.2695 (Office)            adoyle@intl-interfaces.com
+1.781.634.0421 (FAX)
Received on Friday, 30 May 2003 17:21:47 GMT

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