Question

I’m having trouble understanding why a WSDL would be so beneficial, when the truth is that the service definition is not that human-readable, and most developers will use automated tools to consume it to generate objects in the application. Why isn’t it easier for a service provider to define a simple XML schema, and just tell me in the documentation what I can get and how I can get it? I understand the whole ‘universal definition’ aspect, but it all just seems so overcomplicated to me. Most APIs for social sites use a basic RESTful architecture, and all they do is give you a schema representation of the data you will get back. Seriously, I must be missing something here.

Answer 1

At one time, WSDL was popular and I’m sure for internal tools for many companies (and large SOA systems), WSDL is still in use. But you’re correct, the adoption of REST has taken WSDL off the map a bit once it ‘hit the scene’.

Take for example Amazon S3. They offer a WSDL along with the REST API. I had read somewhere that 98% of S3 users are using the REST API and Amazon is considering dropping the WSDL support.

REST is clean. WSDL often depends on other tools to parse it out, or to automatically build functions for your application to benefit from the services offered by the WSDL. REST also has the benefit of being much more natural by taking advantage of HTTP and not really relying on anything more. One you get SOAP into the mix and the many other acronyms that go along with WSDL, you end up with a lot on your hands….