It is common that whenever we talk about SOA, immedietly our discussion will jump into web services, SOAP, WS-* etc. In fact, for many of the techies, SOA mean SOAP and web services. They very rarely give due weighatge to the business side of it. Interestingly, in the recent days more awareness about significance of HTTP in SOA is growing and hence it resulted in more adoption of RESTful services for service enabling applications & business logic than sticking to SOAP/RPC web services. The XML metadata information and SOAP headers associated with webservices are considered to be an overhead than the HTTP headers. When HTTP itself is providing all facilities for an efficient, secured consumption of business logic & data, contractual SOAP web services is loosing its position as a key technology option for enabling services. It is witnessed by the fact that key players in the web like Google, Amazon, Digg, Flickr & Twitter are exposing RESTful services.
Plain Old XML (POX) and Java Script Object Notion (JSON) are the key data formats available from RESTful services. When it comes for data consumption by a machine or application code, JSON is preferrred option over POX because of its smaller foot print. It is also the preferred option for consumption by AJAX applications.
From the development perspective, in Microsoft.Net platform, multiple options are available for developing RESTful services. Either we can leverage Windows Communication Foundation (WCF) or ASP.NET MVC.
So in future, whether we will service enable our applications only through RESTful services or SOAP web services will still exist? We should wait and see.