RESTful API Design

A RESTful API (Representational State Transfer Application Programming Interface.) is a way for different apps or systems to talk to each other over the internet using simple rules. It uses the same rules that web browsers use to load websites (like HTTP). REST APIs are popular because they are easy to use, fast, and can work well even when many users are using them at the same time.

Restaurant Analogy for REST API

Imagine you’re sitting at a restaurant, ready to enjoy a meal. You, the client, are browsing through the menu, which lists all the dishes the restaurant offers - just like an API documentation lists all available endpoints and operations. When you’re ready to order, you don’t walk into the kitchen to make the food yourself. Instead, you call over the waiter, who acts as the API.

You tell the waiter what you want - for example, One Pizza . This is your request (like a GET request in a REST API). The waiter takes your request to the kitchen, which is the server - the place where the real work happens. The chefs prepare the dish (process the request), and the waiter brings the final meal (the response) back to your table.

You don’t need to know how the kitchen operates internally - you just trust that the waiter will handle the communication correctly and return what you asked for. Just like this, in a REST API, the client doesn't need to know how the server processes data -It simply sends requests and gets responses through the API, using a clear and organized set of rules.

Various HTTP Methods Used in REST API

1. GET

• Purpose: Retrieve data from the server.

•     GET /api/users
      GET /api/users/123
  

2. POST

• Purpose: Create a new resource on the server.

•     POST /api/users
      Body: {
        "name": "John",
        "email": "john@example.com"
      }
  

3. PUT

• Purpose: Update a resource entirely (replace).

•     PUT /api/users/123
      Body: {
        "name": "John Updated",
        "email": "john.updated@example.com"
      }
  

4. DELETE

• Purpose: Delete a resource.

•     DELETE /api/users/123
  

5. PATCH

• Purpose: Partially update a resource.

•     PATCH /api/users/123
      Body: {
        "email": "new.email@example.com"
      }
  

Let’s see how to integrate:

const express = require('express');
const router = express.Router();
const {
  getAllBooks,
  getBookById,
  createBook,
  updateBook,
  deleteBook
} = require('../controllers/booksController');

router.get('/', getAllBooks);
router.get('/:id', getBookById);
router.post('/', createBook);
router.put('/:id', updateBook);
router.delete('/:id', deleteBook);

module.exports = router;

Key Differences Between PUT & PATCH

Key Features of REST APIs

1. Scalability

• RESTful APIs use a stateless architecture, which means each request is independent.

• This allows servers to handle more requests efficiently and scale horizontally.

2. Simplicity and Ease of Use

• Uses standard HTTP methods: GET, POST, PUT, DELETE.

• Easy to learn and use with tools like Postman, cURL, or even a browser.

3. Platform Independence

• RESTful APIs can be consumed by clients written in any language (JavaScript, Python, etc.).

• Supports communication between different systems (mobile, web, desktop).

4. Statelessness

• Each request contains all the information needed to process it (no session or server memory needed).

• Improves reliability and scalability.

5. Caching

• REST APIs can leverage HTTP caching mechanisms to improve performance and reduce server load.

6. Flexibility and Modularity

• REST separates client and server, allowing them to evolve independently.

• Clients can request only the data they need.

7. Good for Public APIs

• Easy to expose functionality to third-party developers due to its simplicity and adherence to web standards.

8. Wide Adoption and Tool Support

• REST is widely supported across all major programming languages, libraries, and frameworks.

Typical Project Structure

project/
├── routes/
│   └── userRoutes.js
├── controllers/
│   └── userController.js
├── services/
│   └── userService.js
├── middleware/
│   └── auth.js
├── models/
│   └── userModel.js
└── app.js (main entry)

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