Interview Questions OF REST (Representational state transfer)

What is REST?

Representational state transfer (REST) is an abstraction of architecture of World Wide Web. REST is an architectural style to design networked application. REST makes communication between remote computers easy by using the simple HTTP protocol which support for CRUD (Create, Read, Update, and Delete) operations on the server.

2. The commonly used HTTP methods used in REST based architecture?

GET − Provides a read only access to a resource.

PUT − Used to create a new resource.

DELETE − Used to remove a resource.

POST − Used to update an existing resource or create a new resource.

OPTIONS − Used to get the supported operations on a resource.

3.Resource in REST?

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 client accesses and modifies the resources. Here each resource is identified by URIs/ global IDs.

4.Best practices to design a resource representation?

Following are important points to be considered while designing a representation format of a resource in a RESTful web services −

Understandability − Both Server and Client should be able to understand and utilize 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.

Linkablity − A resource can have a linkage to another resource, a format should be able to handles such situations.

5.The core components of a HTTP Request and HTTP Response?

There are 5 major components for HTTP Request.

Verb − Indicate HTTP methods such as GET, POST, DELETE, PUT etc.

URI − Uniform Resource Identifier (URI) to identify the resource on server.

HTTP Version − Indicate HTTP version, for example HTTP v1.1 .

Request Header − Contains metadata for the HTTP Request message as key-value pairs. For example, client ( or browser) type, format supported by client, format of message body, cache settings etc.

Request Body − Message content or Resource representation.

6. There are 4 major components for HTTP Response.

Status/Response Code − Indicate Server status for the requested resource. For example 404 means resource not found and 200 means response is ok.

HTTP Version − Indicate HTTP version, for example HTTP v1.1.

Response Header − Contains metadata for the HTTP Response message as key-value pairs. For example, content length, content type, response date, server type etc.

Response Body − Response message content or Resource representation.

7. Messaging in RESTful webservices?

A client sends a message in form of a HTTP Request and server responds in form of a HTTP Response. This technique is termed as Messaging. These messages contain message data and metadata i.e. information about message itself.

8. The core components of a HTTP Request?

A HTTP Request has five major parts −

Verb − Indicate HTTP methods such as GET, POST, DELETE, PUT etc.

URI − Uniform Resource Identifier (URI) to identify the resource on server.

HTTP Version − Indicate HTTP version, for example HTTP v1.1.

Request Header − Contains metadata for the HTTP Request message as key-value pairs. For example, client (or browser) type, format supported by client, format of message body, cache settings etc.

Request Body − Message content or Resource representation.

9. Statelessness in RESTful Webservices?

The communication between client and server must be stateless. This means that each request from a service consumer should contain all the necessary information for the service to understand the meaning of the request, and all session state data should then be returned to the service consumer at the end of each request

10. The advantages and disadvantages of statelessness in RESTful Webservices?

Advantages:

Web services can treat each method request independently.

Web services need not to maintain client’s previous interactions. It simplifies application design.

As HTTP is itself a statelessness protocol, RESTful Web services work seamlessly with HTTP protocol

Disadvantages:

Web services need to get extra information in each request and then interpret to get the client’s state in case client interactions are to be taken care of.