RESTful Web Services - Resources

What is a Resource?

REST architecture treats every content as a resource. These resources can be Text Files, Html Pages, Images, Videos or Dynamic Business Data. REST Server simply provides access to resources and REST cpent accesses and modifies the resources. Here each resource is identified by URIs/ Global IDs. REST uses various representations to represent a resource where Text, JSON, XML. The most popular representations of resources are XML and JSON.

Representation of Resources

A resource in REST is a similar Object in Object Oriented Programming or is pke an Entity in a Database. Once a resource is identified then its representation is to be decided using a standard format so that the server can send the resource in the above said format and cpent can understand the same format.

For example, in RESTful Web Services - First Apppcation chapter, a user is a resource which is represented using the following XML format −

<user> 
   <id>1</id> 
   <name>Mahesh</name>
   <profession>Teacher</profession> 
</user> 

The same resource can be represented in JSON format as follows −

{ 
   "id":1, 
   "name":"Mahesh", 
   "profession":"Teacher" 
}

Good Resources Representation

REST does not impose any restriction on the format of a resource representation. A cpent can ask for JSON representation whereas another cpent may ask for XML representation of the same resource to the server and so on. It is the responsibipty of the REST server to pass the cpent the resource in the format that the cpent understands.

Following are some important points to be considered while designing a representation format of a resource in RESTful Web Services.

Understandabipty − Both the Server and the Cpent should be able to understand and utipze the representation format of the resource.

Completeness − Format should be able to represent a resource completely. For example, a resource can contain another resource. Format should be able to represent simple as well as complex structures of resources.

Linkabpty − A resource can have a pnkage to another resource, a format should be able to handle such situations.

However, at present most of the web services are representing resources using either XML or JSON format. There are plenty of pbraries and tools available to understand, parse, and modify XML and JSON data.