Representational state transfer (REST) Architecture

By / March 21, 2023

Back to: Spring Boot Tutorial: Building RESTful APIs from Scratch

Introduction

Representational State Transfer (REST) architecture is a software design pattern commonly used for building web services that are scalable, reliable, and easy to maintain. REST has become a widely adopted architectural style for web applications because of its simplicity, flexibility, and compatibility with existing technologies.

Table Of Contents
  1. Introduction
  2. Basics of REST Architecture
  3. How Does REST Architecture Work?
  4. Components of a REST architecture

REST architecture defines a set of principles and constraints for designing web services that use HTTP protocol for communication. The primary goal of REST is to provide a uniform interface between client and server, allowing them to communicate effectively without any tight coupling. This blog post will explore the basics of REST architecture and how it works.

Basics of REST Architecture

REST architecture is based on four key principles: Resources, Representations, Uniform Interface, and Statelessness. Let’s discuss each of these principles in detail.

  1. Resources: Resources are the key components of REST architecture. A resource is an entity that can be accessed and manipulated through a URI (Uniform Resource Identifier). In REST, everything is considered a resource, including data, images, videos, and any other type of information that can be represented as a resource.
  2. Representations: Representations are the different ways a resource can be presented. A resource can be represented in different formats such as XML, JSON, or HTML. A client can request a specific representation of a resource, and the server will respond with the requested representation.
  3. Uniform Interface: The uniform interface is a set of constraints that simplify communication between the client and the server. The four constraints of the uniform interface are:
  • Identification of resources: Each resource is identified by a unique URI.
  • Manipulation of resources through representations: Clients can manipulate resources through their representations, using standard HTTP methods like GET, POST, PUT, DELETE, etc.
  • Self-descriptive messages: Each message includes enough information to describe how it should be processed.
  • Hypermedia as the engine of application state (HATEOAS): Clients receive hyperlinks within responses that direct them to related resources.
  1. Statelessness: REST architecture is stateless, meaning that each request from the client to the server must contain all the information necessary to understand the request. The server cannot store any information about the client’s previous interactions.

How Does REST Architecture Work?

When a client makes a request to a server using REST architecture, the server responds with a representation of the requested resource. The client can then manipulate the resource by sending additional requests using HTTP methods such as GET, POST, PUT, DELETE, etc.

Let’s take an example of a blog website that uses REST architecture. The blog website has a collection of blog posts, each identified by a unique URI. A client can request a specific blog post by sending a GET request to the server with the URI of the requested blog post. The server will respond with a representation of the requested blog post, in the format requested by the client.

The client can then manipulate the blog post by sending additional requests using HTTP methods such as POST, PUT, or DELETE. For example, if the client wants to update the content of the blog post, they can send a PUT request to the server with the updated content. The server will update the blog post with the new content and respond with a representation of the updated blog post.

Components of a REST architecture

  1. Clients: Clients are the end-users or applications that interact with the web services provided by the server. Clients use HTTP methods such as GET, POST, PUT, DELETE, etc. to send requests to the server.
  2. Resources: Resources are the entities that can be accessed and manipulated through a URI. Resources can be represented in different formats such as XML, JSON, or HTML.
  3. URIs: Uniform Resource Identifiers (URIs) uniquely identify resources. Each resource is assigned a unique URI that can be used to access and manipulate it.
  4. HTTP Methods: HTTP methods are used to manipulate resources. The most commonly used HTTP methods are GET, POST, PUT, and DELETE.
  5. Representations: Representations are the different ways a resource can be presented. A resource can be represented in different formats such as XML, JSON, or HTML.
  6. Response Codes: Response codes are used to indicate the status of a request. The most commonly used response codes are 200 (OK), 201 (Created), 204 (No Content), 400 (Bad Request), 401 (Unauthorized), 404 (Not Found), and 500 (Internal Server Error).
  7. Message Headers: Message headers are used to provide additional information about the request or response. Examples of message headers include Content-Type, Accept, Authorization, and Cache-Control.

Overall, a REST architecture is a simple and flexible approach to designing web services that allow for efficient communication between the client and the server.

Also, see the example code JavaExamples_NoteArena in our GitHub repository. See complete examples in our GitHub repositories.

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Mamun Kayum