What is REST API? | REST API Tutorial | REST API Concepts and Examples | Edureka

Introduction

This tutorial explains the concept of REST APIs, their features, principles, methods, and implementation. Understanding REST APIs is crucial for web developers and anyone involved in software development, as they enable communication between different software systems.

Step 1: Understanding the Need for REST API

• What is REST API?

  • REST (Representational State Transfer) is an architectural style for designing networked applications.
  • It allows systems to communicate over HTTP, making it easier to build scalable and stateless services.

• Why REST APIs?

  • They provide a flexible way to interact with web services.
  • REST APIs facilitate easy integration between different systems and platforms.

Step 2: Key Features of REST API

• Statelessness

  • Each API call contains all the information needed to process the request, improving scalability.

• Resource-Based

  • Interactions are centered on resources, which are identified by URIs (Uniform Resource Identifiers).

• HTTP Methods

  • REST APIs utilize standard HTTP methods such as GET, POST, PUT, DELETE for operations.

• Representation

  • Resources can be represented in multiple formats like JSON, XML, or HTML.

Step 3: Principles of REST API

• Client-Server Architecture

  • Separation of client and server responsibilities enhances portability and scalability.

• Stateless Communication

  • Each request from the client to the server must contain all the information needed to understand and process it.

• Cacheable Responses

  • Responses must define themselves as cacheable or non-cacheable to improve performance.

• Layered System

  • A client cannot tell whether it is connected directly to the end server or an intermediary.

Step 4: Methods of REST API

• GET

  • Used to retrieve data from a server.

• POST

  • Used to send data to the server to create a new resource.

• PUT

  • Used to update an existing resource on the server.

• DELETE

  • Used to remove a resource from the server.

Step 5: Implementing a REST API

1. Choose a Framework

   • Select a framework that suits your programming language. For Node.js, you can use Express.js.

2. Set Up Your Environment

   • Install Node.js and necessary packages:

     npm install express
     

3. Create Your Server

   • Set up a basic server structure:

     const express = require('express');
     const app = express();
     const PORT = process.env.PORT || 3000;
     
     app.listen(PORT, () => {
       console.log(`Server running on port ${PORT}`);
     });
     

4. Define Your API Endpoints

   • Create routes for each method:

     app.get('/resources', (req, res) => {
       // logic to retrieve resources
     });
     
     app.post('/resources', (req, res) => {
       // logic to create a new resource
     });
     
     app.put('/resources/:id', (req, res) => {
       // logic to update a resource by ID
     });
     
     app.delete('/resources/:id', (req, res) => {
       // logic to delete a resource by ID
     });
     

5. Test Your API

   • Use tools like Postman to test your API endpoints and ensure they function as expected.

Conclusion

In this tutorial, we've covered the essentials of REST APIs including their need, features, principles, methods, and implementation steps. To deepen your understanding, consider creating a simple REST API project or exploring existing APIs. This knowledge is fundamental for building scalable web applications and integrating different services effectively.