Alex Barnett blog


Does REST need a WSDL?

First read this (written by Marc Hadley)

"This article describes the Web Application Description Language (WADL). An increasing number of Web-based enterprises (Google, Yahoo, Amazon, Flickr - to name but a few) are developing HTTP-based applications that provide access to their internal data using XML. Typically these applications are described using a combination of textual protocol descriptions combined with XML schema-based data format descriptions; WADL is designed to provide a machine processable protocol description format for use with such HTTP-based Web applications, especially those using XML."

 Then read this by Sam Ruby:

"Those that merely attempt to produce compliant WSDL based on the available specifications often find problems such as these.  But the siren call for viewing the programmable web as merely a serialization format seems unstoppable: the current incarnation is called WADL."

Then read this: Automatic Multi Language Program Library Generation for REST APIs, by Thomas Steiner

"The question of describing (REST) web services in a machine-readable way other than WSDL has been raised before[9]. However, often the motivation behind was more to get rid of WSDL rather than actually solving the REST description issues. Many suggestions are more or less ad hoc inventions designed to solve particular problems. It is to be noted that with WSDL 2.0 it is possible to describe REST services[10], but here we want to focus on some examples of non-WSDL approaches. As Sun Microsystem's Norman Walsh writes[11]: "We know the hard things are possible, we just have to make the easy things easy." "

Then see this, also by Thomas Steiner.

What do you think?

-shutting down comments on this post due to spam-


Tommy Williams said:

I loves me some REST just like the rest of the people out there, but I like it for its informality and hackability. If I want strong contracts and a layer of abstraction on top of Web services, I'll stick with WSDL and WS-*.

Both approaches have their place. Why muddy the waters and dilute one of the biggest benefits of REST -- its simplicity and low barrier to entry?

# March 13, 2007 6:23 PM

alexbarnett said:

# March 14, 2007 8:22 AM

TrackBack said:

Does REST need WSDL? In response to Alex Barnett: Yes it does! But WADL only gets us so far. We need to...
# March 16, 2007 10:27 AM