Building a RESTful API with Node.js, Express, and MongoDB: A Step-by-Step Guide

In this tutorial, we’ll walk through how to set up a RESTful API using Node.js, Express, and MongoDB. We’ll cover creating routes to perform CRUD operations (Create, Read, Update, Delete) on MongoDB documents. By the end, you’ll have a functioning API that can handle basic database interactions.

Prerequisites

• Node.js installed on your machine
• Basic understanding of JavaScript and Node.js
• MongoDB installed locally or a MongoDB Atlas account (for cloud hosting)

Step 1: Set Up Your Project

Start by setting up a new Node.js project. Open your terminal and run the following commands:

mkdir node-express-mongodb-api
cd node-express-mongodb-api
npm init -y

Next, install the required dependencies:

npm install express mongoose body-parser

• Express: For building the RESTful API framework
• Mongoose: MongoDB object modeling tool for Node.js
• body-parser: Middleware to parse incoming request bodies

Step 2: Create an Express Server

Create a new file named index.js in the project root directory.

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

const app = express();
const PORT = process.env.PORT || 3000;

// Middleware
app.use(bodyParser.json());

// MongoDB Connection
mongoose.connect('mongodb://localhost/mydatabase', {
  useNewUrlParser: true,
  useUnifiedTopology: true
});
const db = mongoose.connection;
db.on('error', console.error.bind(console, 'MongoDB connection error:'));
db.once('open', () => {
  console.log('Connected to MongoDB');
});

// Routes
app.get('/', (req, res) => {
  res.send('Welcome to the API');
});

// Start the server
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});

Step 3: Define MongoDB Schema and Model

Create a new folder named models and inside it, create a file item.js.

const mongoose = require('mongoose');

const itemSchema = new mongoose.Schema({
  name: { type: String, required: true },
  description: { type: String }
});

const Item = mongoose.model('Item', itemSchema);

module.exports = Item;

Step 4: Create CRUD Routes

Create a new folder named routes and inside it, create a file items.js.

const express = require('express');
const router = express.Router();
const Item = require('../models/item');

// Create a new item
router.post('/', async (req, res) => {
  try {
    const newItem = await Item.create(req.body);
    res.status(201).json(newItem);
  } catch (err) {
    res.status(400).json({ message: err.message });
  }
});

// Get all items
router.get('/', async (req, res) => {
  try {
    const items = await Item.find();
    res.json(items);
  } catch (err) {
    res.status(500).json({ message: err.message });
  }
});

// Update an item
router.patch('/:id', async (req, res) => {
  try {
    const updatedItem = await Item.findByIdAndUpdate(req.params.id, req.body, { new: true });
    res.json(updatedItem);
  } catch (err) {
    res.status(400).json({ message: err.message });
  }
});

// Delete an item
router.delete('/:id', async (req, res) => {
  try {
    await Item.findByIdAndDelete(req.params.id);
    res.json({ message: 'Item deleted' });
  } catch (err) {
    res.status(400).json({ message: err.message });
  }
});

module.exports = router;

Step 5: Integrate Routes with Express Server

Update index.js to use the items routes.

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

const app = express();
const PORT = process.env.PORT || 3000;

// Middleware
app.use(bodyParser.json());

// MongoDB Connection
mongoose.connect('mongodb://localhost/mydatabase', {
  useNewUrlParser: true,
  useUnifiedTopology: true
});
const db = mongoose.connection;
db.on('error', console.error.bind(console, 'MongoDB connection error:'));
db.once('open', () => {
  console.log('Connected to MongoDB');
});

// Routes
const itemsRouter = require('./routes/items');
app.use('/items', itemsRouter);

// Start the server
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});

Step 6: Test Your API

Start your Node.js server by running node index.js in the terminal. Use tools like Postman or curl to interact with your API endpoints:

• POST /items: Create a new item
• GET /items: Get all items
• PATCH /items/:id: Update an item
• DELETE /items/:id: Delete an item

Conclusion

You’ve successfully set up a RESTful API using Node.js, Express, and MongoDB! This example covers basic CRUD operations. You can expand this project by adding authentication, error handling, input validation, and more complex querying.