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

Initialize a new Node.js project:

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

Install dependencies:

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

Install additional tools:
```
npm install express-validator
```

3. Set Up MongoDB

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

Create the directory structure:

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

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

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

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

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

Start the server:
```
nodemon src/server.js
```
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

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.

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