Shiju Varghese's Blog Headline

Shiju Varghese's Blog

Wednesday, December 5, 2007

REST and WCF 3.5

The first version of WCF was focused on SOAP. But another approach known as REST is becoming a popular approach for building web services. The latest version of WCF in the .NET Framework 3.5 supports both SOAP and REST.

What is REST?

REST is an acronym standing for Representational State Transfer and it is an architecture style of networked systems. According to Roy Fielding (one of the principal authors of the Hypertext Transfer Protocol (HTTP) specification) , the explanation of Representational State Transfer is :
"Representational State Transfer is intended to evoke an image of how a well-designed Web application behaves: a network of web pages (a virtual state-machine), where the user progresses through an application by selecting links (state transitions), resulting in the next page (representing the next state of the application) being transferred to the user and rendered for their use." Systems that follow Fielding’s REST principles are commonly known as “RESTful”;

REST means that each unique URL is a representation of some object. You can get the contents of that object using an HTTP GET, to delete it, you then might use a POST, PUT, or DELETE to modify the object.

Unlike SOAP, REST is not a standard or specification. It is just an architectural style. You can design your web services using this architectural style.

REST is using the built-in operations in HTTP: GET, POST, and others. And rather than identify the information to be accessed with parameters defined in XML, as SOAP typically does, REST assumes that everything is identified with a URL. However REST is not a standard, it does use the following standards

  • HTTP

  • URL

  • XML/HTML/GIF/JPEG/etc (Resource Representations)

  • text/xml, text/html, image/gif, image/jpeg, etc

REST Vs SOAP - Which is the best approach?

Software Architects have been involving a never-ending debate about whether SOAP-based or REST-style web services are the right approach and recently the debate is too heating up. Yahoo's web services are using REST and google using SOAP for their web services. Some organizations have web services for both REST and SOAP. REST is Lightweight than SOAP because it does not requires lot of xml markup like SOAP.
I believe that SOAP will be the primary choice for intranet and enterprise level applications because SOAP and the WS-* specifications addresses many challenges of enterprise level applications such as reliability, distributed transactions, and other WS-* services. But I think open, Internet applications will gear towards to REST because of REST’s explicitly Web-based approach and its simplicity.

RESTful services for WCF 3.5

WCF 3.5 provides explicit support for RESTful communication using a new binding named WebHttpBinding.
The below code shows how to expose a RESTful service

interface IStock
int GetStock(string StockId);

By adding the WebGetAttribute, we can define a service as REST based service that can be accessible using HTTP GET operation.

No comments: