RE: XML protocol comparisons


 Here are a few corrections and updates on the status of WDDX (Web
Distributed Data Exchange).

Releases: released in October 1998 under an open source license, with
reference SDK.  Went final in January 2000 (WDDX 1.0) after broad use and
extensive testing during 1999.

Proponent:  Allaire Corporation, though the SDK and reference
implementations are managed outside of Allaire and contributed by a variety
of vendors and communities.

Architects:  Simeon Simeonov (Allaire), Nate Weiss (independent/JavaScript),
Spike Washburn (Allaire/Java), Rasmus Lerdorf (PHP3), Scott Guelich


  * Public Forums --
  * Browsable SDK --
  * Download SDK --


  * WDDX SDK has been downloaded by over 10,000 developers
  * WDDX modules have been natively included for over a year in ColdFusion;
we believe about 20% of the installed base uses WDDX for a variety of data
exchange and data persistence applications
  * WDDX modules are bundled with JRun (JSP/Servlets/EJB/JMS server)
  * PHP3/4 bundles WDDX and uses it for data exchange, session data
persistence and object storage
  * Python bundles a WDDX .9 module
  * Complete modules are available for CF, Java, COM, Perl, JavaScript, PHP
and Python
  * We estimate that there are many thousands of applications deployed using


WDDX was built as a very pragmatic, pre-namespace and pre-schema data
serialization and exchange model for Internet programming languages.
Because of its simplicity and reliance on only XML 1.0, it has been widely
deployed on many popular language platforms.  

Also, because it solves very concrete problems for Internet application
developers, such as simple data persistence, data exchange and
browser-to-server and server-to-browser communication, many Web developers
are using it as a flexible utility.  WDDX implementations (modules listed
above) remove from the developer having to have any knowledge of XML, XML
formats, etc.

WDDX supports basic and complex data-types; dateTime, numeric, boolean,
binary(base64), strings, arrays, recordsets and object structures.

A variety of utilities accompany the various language modules to make common
transformations easy; eg. ADO recordset to JavaScript recordset, Java or
Perl hash tables to WDDX structure, JavaBean to WDDX object, and vice versa
for all of the above.

Protocol Layers:  

Because WDDX is a simple, core technology we've found a variety of
higher-level protocol-oriented applications have been layered on top of it.
The most comprehensive implementation is included with Spectra, Allaire's
packaged commerce software product.  Using, WDDX, it includes:
  * Discovery services via a standard meta-data search API
  * Request/response semantics
  * Authentication and object permissions (pluggable)
  * Simple, standard error/exception codes

Because this implementation is tied to Spectra, it is not in the public
domain or implemented for other platforms.  The mechanisms and
syntax/structure could easily be replicated on other platforms.

We view the work with WDDX is an excellent testbed and set of reference work
for understanding how Web application developers want to use XML protocols
and middleware, but are pretty committed to evolving the infrastructure to
be in line with whatever this community determines is the *right* standard
and approach.


-----Original Message-----
From: Eric Prud'hommeaux
Sent: 3/29/00 8:17 PM
Subject: XML protocol comparisons

I put together a comparison of a bunch of XML protocols, 

ICE []
BizTalk []
TIP []
WfXML []
ebXML []
XMI []

for everyone to discuss/dispute. It is said that the best way to get a
question answered on usenet is to post an incorrect answer. Persuant
to that, I have not done extensive readings of some of the protocol
papers during my characterizations, but at least they're all there in
a forum where we can compare apples and fruit baskets.

I'll be adding more dimensions and would like feedback on what people
wish to compare. Also, I'd like to have anchor-rich HTML versions of
the documents so I can point to specific parts of the spec as
supporting evidence.



Received on Friday, 31 March 2000 10:40:20 UTC