Node js Rest API

Creating a REST API using Node.js in the MERN stack involves several steps, including setting up MongoDB, creating the backend with Express, and using tools like Postman to test the API. Here's a detailed guide to help you through the process:

1. Set Up Your Environment

Install Node.js and npm

Download and install Node.js from nodejs.org. npm is included with Node.js.

Install MongoDB

Download and install MongoDB from mongodb.com.

2. Create a New Project

1. Initialize a new Node.js project:
   

   mkdir mern-rest-api
   cd mern-rest-api
   npm init -y
   

2. Install dependencies:
   

   npm install express mongoose body-parser cors
   npm install --save-dev nodemon
   

3. Install additional tools:
   

   npm install express-validator
   

3. Set Up MongoDB

1. Start MongoDB:

   • On Windows: Run mongod in your terminal.
   • On Mac: You can use brew services start mongodb-community.

2. Create a new database and collection:

   • Use MongoDB Compass or the MongoDB shell to create a new database (e.g., mern_db) and a collection (e.g., users).

4. Create the Express Server

1. Create the directory structure:
   

   mkdir src
   cd src
   mkdir config controllers models routes
   touch server.js
   

2. Set up the server.js file:
   

   const express = require('express');
   const mongoose = require('mongoose');
   const bodyParser = require('body-parser');
   const cors = require('cors');
   
   const app = express();
   
   // Middleware
   app.use(bodyParser.json());
   app.use(cors());
   
   // MongoDB connection
   mongoose.connect('mongodb://localhost:27017/mern_db', {
       useNewUrlParser: true,
       useUnifiedTopology: true,
   });
   
   mongoose.connection.once('open', () => {
       console.log('Connected to MongoDB');
   });
   
   // Routes
   const users = require('./routes/users');
   app.use('/api/users', users);
   
   const PORT = process.env.PORT || 5000;
   
   app.listen(PORT, () => {
       console.log(`Server is running on port ${PORT}`);
   });
   

5. Create Models

1. Create models/User.js:
   

   const mongoose = require('mongoose');
   
   const UserSchema = new mongoose.Schema({
       name: {
           type: String,
           required: true,
       },
       email: {
           type: String,
           required: true,
           unique: true,
       },
       password: {
           type: String,
           required: true,
       },
   });
   
   module.exports = mongoose.model('User', UserSchema);
   

6. Create Controllers

1. Create controllers/userController.js:
   

   const User = require('../models/User');
   const { body, validationResult } = require('express-validator');
   
   // Get all users
   exports.getUsers = async (req, res) => {
       try {
           const users = await User.find();
           res.json(users);
       } catch (err) {
           res.status(500).json({ message: err.message });
       }
   };
   
   // Create a new user
   exports.createUser = [
       body('name').notEmpty().withMessage('Name is required'),
       body('email').isEmail().withMessage('Email is not valid'),
       body('password').isLength({ min: 6 }).withMessage('Password must be at least 6 characters long'),
   
       async (req, res) => {
           const errors = validationResult(req);
           if (!errors.isEmpty()) {
               return res.status(400).json({ errors: errors.array() });
           }
   
           const { name, email, password } = req.body;
           try {
               const user = new User({ name, email, password });
               await user.save();
               res.status(201).json(user);
           } catch (err) {
               res.status(500).json({ message: err.message });
           }
       },
   ];
   

7. Create Routes

1. Create routes/users.js:
   

   const express = require('express');
   const router = express.Router();
   const userController = require('../controllers/userController');
   
   // Get all users
   router.get('/', userController.getUsers);
   
   // Create a new user
   router.post('/', userController.createUser);
   
   module.exports = router;
   

8. Test the API with Postman

1. Start the server:
   

   nodemon src/server.js
   

2. Open Postman and create a new request:

- **GET** `http://localhost:5000/api/users` to fetch all users.
- **POST** `http://localhost:5000/api/users` to create a new user. In the body, use the following JSON format:

    ```json
    {
        "name": "thirdearnest123",
        "email": "thirdearnest123@example.com",
        "password": "password123"
    }
    ```

Useful Resources

• Node.js
• Express.js
• MongoDB
• Postman
• Mongoose
• Express Validator

By following these steps, you will have a basic REST API setup using the MERN stack. You can further expand this by adding more features, authentication, and front-end integration.