REST in peace

Representational State Transfer (REST) is an architectural pattern used in the design of services. REST is about the way in which you expose and make available to callers the contract of the service. REST, therefore, is opposed to SOAP.

A SOAP-based service uses a single URL to expose all functionalities and documents it through WSDL or a contract name. A REST service uses distinct URLs to point to distinct functionalities. A REST service documents functionalities through links and HTTP headers. Each operation has a unique URL plus optional HTTP headers.

Services consumed by AJAX applications should adhere to REST principles. But what if you use ASP.NET AJAX Extensions? Not so many ASP.NET AJAX developers know about REST. So what?

In ASP.NET AJAX you write RPC-style services (i.e., local Web services or page methods) but they're internally implemented through a REST-based HTTP handler. So the REST pattern does exist in ASP.NET AJAX but it's not exposed (with all of its benefits--mostly extensibility) to end developers. This is not necessarily a bad news. In the end, ASP.NET AJAX Extensions gives you a familiar programming interface and no additional burden.  But if you put your hands on any AJAX books out there you inevitably find that mentioned. And no mention of it in ASP.NET AJAX Extensions.

Now you know why :)