Building a RESTful API with Node.js and Express

Introduction to RESTful APIs

A RESTful API (Application Programming Interface) is an architectural style for designing networked applications. It is based on the idea of resources, which are identified by URIs, and can be manipulated using a fixed set of operations.

Step 1: Install Required Packages

First, you need to install the required packages. Run the following command in your terminal:

npm install express body-parser

Step 2: Create a New Express App

Create a new file called app.js and add the following code to it:

const express = require('express');
const bodyParser = require('body-parser');
const app = express();

app.use(bodyParser.json());

const port = 3000;

Step 3: Define API Endpoints

Define API endpoints for creating, reading, updating, and deleting resources. For example, let's say we want to manage a list of books. We can define the following endpoints:

let books = [
  { id: 1, title: 'Book 1', author: 'Author 1' },
  { id: 2, title: 'Book 2', author: 'Author 2' }
];

app.get('/books', (req, res) => {
  res.json(books);
});

app.get('/books/:id', (req, res) => {
  const id = req.params.id;
  const book = books.find((book) => book.id === parseInt(id));
  if (!book) {
    res.status(404).json({ message: 'Book not found' });
  } else {
    res.json(book);
  }
});

app.post('/books', (req, res) => {
  const { title, author } = req.body;
  const newBook = { id: books.length + 1, title, author };
  books.push(newBook);
  res.json(newBook);
});

app.put('/books/:id', (req, res) => {
  const id = req.params.id;
  const book = books.find((book) => book.id === parseInt(id));
  if (!book) {
    res.status(404).json({ message: 'Book not found' });
  } else {
    const { title, author } = req.body;
    book.title = title;
    book.author = author;
    res.json(book);
  }
});

app.delete('/books/:id', (req, res) => {
  const id = req.params.id;
  const index = books.findIndex((book) => book.id === parseInt(id));
  if (index === -1) {
    res.status(404).json({ message: 'Book not found' });
  } else {
    books.splice(index, 1);
    res.json({ message: 'Book deleted' });
  }
});

Step 4: Start the Server

Start the server by running the following command in your terminal:

node app.js

You can now use a tool like curl or a REST client to test your API endpoints.