RE: Visibility (was Re: Introducing the Service Oriented Architec tural style, and it's constraints and properties.

+1

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 02/19/2003 06:47:25 PM:

> 
> > 
> > 
> > -----Original Message-----
> > From: Mark Baker [mailto:distobj@acm.org] 
> > Sent: Wednesday, February 19, 2003 6:26 PM
> > To: dorchard@bea
> > Cc: www-ws-arch@w3.org
> >
> 
> > On Wed, Feb 12, 2003 at 10:01:31PM -0800, dorchard@bea wrote:
> > > The RESTful SOA has the advantage better visibility, as the 
> > firewall 
> > > can simply examine the generic interface to determine the 
> > action being
> > > performed.   Intermediaries, such as HTTP routers or 
> > caches, can simply look
> > > at the method.  An example is that a cache can look at the 
> > GET and the 
> > > identifier, and return a cached representation.  This is much more 
> > > difficult if the method is in arbitrary places in the POST. 
> > > Re-usability can be higher as the service may be available 
> > on the Web 
> > > as a URI may be transferable.
> > 
> > I agree with him completely.
> 
> The only part I disagree with is "much" in "much more difficult."   Sure
> it's easier to write a firewall that only looks at HTTP headers and not 
the
> SOAP content of a message, but it's do-able to build XML/SOAP-aware
> firewalls, it's being done, and this is practical mainly because XML and
> SOAP provide a framework that is flexible enough to be useful for most
> anything but "visible" via standard XML toolkits.
> 
> Obviously this extends to routers as well; SOAP-aware routers would work
> with any protocol -- FTP, SMTP, BEEP, TCP/IP, MQ -- as well as HTTP. XML
> standards (e.g. Xpath) allow routing based on message content as well as 
the
> headers.  I think of this as a feature to be valued, e.g. in spam 
filters. 
> 
> So again, I agree that "visibility" is an important property, but what
> powers it is *standards*, not just HTTP. 
> 
>