Chorn Sokun’s Weblog

What is REST?

REST stands for Representational State Trasfer an important concept in REST is the existence of resources (sources of specific information), each of which is referenced with a global identifier (e.g., a URI in HTTP).

How does it work?

REST take advantage of HTTP methods such as POST, GET, PUT and DELETE and translate the request as CREATE, READ, UPDATE, DELETE (CRUD) operation associated with database technologies.

REST application might define resources URI such as:

http://example.com/albums

http://example.com/albums/{id}

http://example.com/albums/{id}/slideshow

and client code would look something like this:

Resource userResource = new Resource('http://example.com/users/001');
userResource.delete();

It is simple enough, right?

RESTful Castle

REST needed URI to begin with; now if you are assigned to design a server side code for that what are you gonna do? Well, you simple need an URL Rewrite tools to save day, don’t you? So what does URL Rewrite tools do? Simply it would intercept incoming HTTP request and route to relevant destination (.php, .cgi, .aspx, .asmx scripts etc). It is pretty trivial to do it on apache web server:

1. Make sure mod_urlrewrite is enabled
2. define a few rules in .htaccess (hmm, regex not so funny)

[ControllerDetails(Area="admin")]
public class UsersController : Controller
{
   public void Index()
   {
   }
}

Notice the use of ControllerDetails attribute which usually allow you to tell MonoRail how a controller can be found. The important part of ControllerDetails above is Area = “admin” which is very flexible and that mean you can burried a controller down as deep as you want it to be.

Is that mean I can have a controller defined and it will generate URI like this?

http://example.com/albums

http://example.com/albums/{id}

http://example.com/albums/{id}/slideshow

With controller alone? you basically can’t do, because controller generated URI in the form /area/controller/action.rails?id={id} to do a nice RESTful like URI you need another tool similar to URL Rewrite lucky enough MR got a build-in tool for that it located here Castle.MonoRail.Framework.Routing … going to talk more in the future.

Limitation & Workaround

* Public Access

http://example.com/albums

http://example.com/albums/{id}

http://example.com/albums/{id}/slideshow

* Authorization Access

http://example.com/users/albums

http://example.com/users/albums/{id}

http://example.com/users/albums/{id}/slideshow

[ControllerDetails("album", Area="users")]

public class WhatTheF_CKAlbumController{

    ... same code old code

}