Node Express Crud App w MongoDB

Creating an Express CRUD REST API with a full MVC system and a Mongoose database involves several steps. Here’s a comprehensive guide to set it up, including an explanation of the plugins used and the overall app structure.

Plugins and Packages Used

Express: A web application framework for Node.js, designed for building web applications and APIs.
Mongoose: An Object Data Modeling (ODM) library for MongoDB and Node.js. It manages relationships between data and provides schema validation.
Nodemon: A utility that monitors for any changes in your source and automatically restarts your server.
Dotenv: A module to load environment variables from a .env file into process.env.
Body-Parser: Middleware to parse incoming request bodies in a middleware before your handlers, available under the req.body property.
Cors: Middleware to enable Cross-Origin Resource Sharing.

App Structure

project
│   .env
│   .gitignore
│   package.json
│   server.js
│
└───config
│   │   db.js
│
└───controllers
│   │   userController.js
│
└───models
│   │   userModel.js
│
└───routes
│   │   userRoutes.js
│
└───middleware
    │   errorMiddleware.js

Step-by-Step Implementation

Step 1: Initialize the Project

mkdir project               # Create project directory
cd project                  # Navigate to project directory
npm init -y                 # Initialize a new Node.js project with default settings
npm install express mongoose nodemon dotenv body-parser cors # Install necessary packages

Step 2: Setup `.env` File

Create a .env file in the root of your project:

PORT=3000                   # Port number for the server
MONGO_URI=your_mongo_db_connection_string # MongoDB connection string

Step 3: Create `server.js`

Create server.js in the root directory:

const express = require('express');         // Import express
const mongoose = require('mongoose');       // Import mongoose
const bodyParser = require('body-parser');  // Import body-parser for parsing request bodies
const cors = require('cors');               // Import cors for handling Cross-Origin Resource Sharing
const dotenv = require('dotenv');           // Import dotenv for environment variables
const userRoutes = require('./routes/userRoutes'); // Import user routes
const errorMiddleware = require('./middleware/errorMiddleware'); // Import error middleware

dotenv.config();                            // Load environment variables

const app = express();                      // Initialize express app

// Middleware setup
app.use(bodyParser.json());                 // Parse JSON bodies
app.use(cors());                            // Enable CORS
app.use('/api/users', userRoutes);          // Use user routes
app.use(errorMiddleware);                   // Use error middleware

const PORT = process.env.PORT || 5000;      // Define the port

mongoose.connect(process.env.MONGO_URI, { useNewUrlParser: true, useUnifiedTopology: true }) // Connect to MongoDB
    .then(() => {
        app.listen(PORT, () => console.log(`Server running on port ${PORT}`)); // Start the server
    })
    .catch(err => console.error(err));      // Handle connection errors

Step 4: Setup Database Configuration

Create config/db.js:

const mongoose = require('mongoose');       // Import mongoose

const connectDB = async () => {
    try {
        await mongoose.connect(process.env.MONGO_URI, {
            useNewUrlParser: true,          // Use new URL parser
            useUnifiedTopology: true,       // Use unified topology
        });
        console.log('MongoDB connected...'); // Log successful connection
    } catch (err) {
        console.error(err.message);         // Log connection errors
        process.exit(1);                    // Exit process with failure
    }
};

module.exports = connectDB;                 // Export the connection function

Step 5: Create Mongoose Model

Create models/userModel.js:

const mongoose = require('mongoose');       // Import mongoose

const userSchema = new mongoose.Schema({    // Define user schema
    name: {
        type: String,
        required: true,
    },
    email: {
        type: String,
        required: true,
        unique: true,
    },
    password: {
        type: String,
        required: true,
    },
}, {
    timestamps: true,                       // Add createdAt and updatedAt fields
});

const User = mongoose.model('User', userSchema); // Create user model

module.exports = User;                      // Export user model

Step 6: Create Controllers

Create controllers/userController.js:

const User = require('../models/userModel'); // Import user model

// Get all users
const getUsers = async (req, res) => {
    try {
        const users = await User.find();     // Find all users
        res.json(users);                     // Return users in JSON format
    } catch (err) {
        res.status(500).json({ message: err.message }); // Handle errors
    }
};

// Get a single user
const getUser = async (req, res) => {
    try {
        const user = await User.findById(req.params.id); // Find user by ID
        if (!user) return res.status(404).json({ message: 'User not found' }); // Handle user not found
        res.json(user);                     // Return user in JSON format
    } catch (err) {
        res.status(500).json({ message: err.message }); // Handle errors
    }
};

// Create a new user
const createUser = async (req, res) => {
    const user = new User({
        name: req.body.name,
        email: req.body.email,
        password: req.body.password,
    });

    try {
        const newUser = await user.save();  // Save new user
        res.status(201).json(newUser);      // Return new user in JSON format
    } catch (err) {
        res.status(400).json({ message: err.message }); // Handle errors
    }
};

// Update a user
const updateUser = async (req, res) => {
    try {
        const user = await User.findById(req.params.id); // Find user by ID
        if (!user) return res.status(404).json({ message: 'User not found' }); // Handle user not found

        user.name = req.body.name || user.name;
        user.email = req.body.email || user.email;
        user.password = req.body.password || user.password;

        const updatedUser = await user.save(); // Save updated user
        res.json(updatedUser);                // Return updated user in JSON format
    } catch (err) {
        res.status(400).json({ message: err.message }); // Handle errors
    }
};

// Delete a user
const deleteUser = async (req, res) => {
    try {
        const user = await User.findById(req.params.id); // Find user by ID
        if (!user) return res.status(404).json({ message: 'User not found' }); // Handle user not found

        await user.remove();                 // Remove user
        res.json({ message: 'User removed' }); // Return success message
    } catch (err) {
        res.status(500).json({ message: err.message }); // Handle errors
    }
};

module.exports = {
    getUsers,
    getUser,
    createUser,
    updateUser,
    deleteUser,
};                                           // Export all controller functions

Step 7: Create Routes

Create routes/userRoutes.js:

const express = require('express');         // Import express
const {
    getUsers,
    getUser,
    createUser,
    updateUser,
    deleteUser,
} = require('../controllers/userController'); // Import controller functions

const router = express.Router();            // Create router

router.route('/')
    .get(getUsers)                          // Route to get all users
    .post(createUser);                      // Route to create a user

router.route('/:id')
    .get(getUser)                           // Route to get a user by ID
    .put(updateUser)                        // Route to update a user by ID
    .delete(deleteUser);                    // Route to delete a user by ID

module.exports = router;                    // Export router

Step 8: Create Error Middleware

Create middleware/errorMiddleware.js:

const errorMiddleware = (err, req, res, next) => {
    const statusCode = res.statusCode !== 200 ? res.statusCode : 500; // Determine status code
    res.status(statusCode);
    res.json({
        message: err.message,
        stack: process.env.NODE_ENV === 'production' ? null : err.stack, // Show stack trace only in development
    });
};

module.exports = errorMiddleware;           // Export error middleware

Step 9: Run the Server

Add a start script in package.json:

"scripts": {
    "start": "node server.js",             // Script to start the server
    "dev": "nodemon server.js"             // Script to start the server with nodemon
}

Run the server:

npm run dev                                # Start the server in development mode

Diagram of the App Structure

project
│
├── .env               # Environment variables
├── .gitignore         # Git ignore file
├── package.json       # Project metadata and dependencies
├── server.js          # Entry point of the application
│
├── config             # Configuration files
│   └── db.js          # Database configuration
│
├── controllers        # Controller files
│   └── userController.js
│
├── models             # Mongoose models
│   └── userModel.js
│
├── routes             # Route handlers
│   └── userRoutes.js
│
└── middleware         # Custom middleware
    └── errorMiddleware.js

This structure provides a modular approach to developing an Express application with a clear separation of concerns, making the app scalable and maintainable.

Postman Setup

Postman is a popular tool to test APIs. You can set up collections and environment variables to easily test your endpoints.

Install Postman: Download and install Postman from here.
Create a new collection: Click on “New” and then “Collection”. Name your collection (e.g., “User API”).
Add requests: For each endpoint (e.g., GET /api/users, POST /api/users, etc.), create a new request inside your collection.

Postman Collection Setup

Create Collection: In Postman, create a new collection named “User API”.
Create Requests:
- GET /api/users:
  - Method: GET
  - URL: http://localhost:3000/api/users
- POST /api/users:
  - Method: POST
  - URL: http://localhost:3000/api/users
  - Body: raw JSON

{
    "name": "John Doe",
    "email": "john@example.com",
    "password": "password123"
}

GET /api/users/:id:
- Method: GET
- URL: http://localhost:3000/api/users/{{id}}
- (Replace {{id}} with a valid user ID)
PUT /api/users/:id:
- Method: PUT
- URL: http://localhost:3000/api/users/{{id}}
- Body: raw JSON

{
    "name": "Jane Doe",
    "email": "jane@example.com",
    "password": "newpassword123"
}

DELETE /api/users/:id:
- Method: DELETE
- URL: http://localhost:3000/api/users/{{id}}
- (Replace {{id}} with a valid user ID)

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Node Express Crud App w MongoDB

Plugins and Packages Used

App Structure

Step-by-Step Implementation

Step 1: Initialize the Project

Step 2: Setup `.env` File

Step 3: Create `server.js`

Step 4: Setup Database Configuration

Step 5: Create Mongoose Model

Step 6: Create Controllers

Step 7: Create Routes

Step 8: Create Error Middleware

Step 9: Run the Server

Diagram of the App Structure

Postman Setup

Postman Collection Setup

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Node Express Crud App w MongoDB

Plugins and Packages Used

App Structure

Step-by-Step Implementation

Step 1: Initialize the Project

Step 2: Setup .env File

Step 3: Create server.js

Step 4: Setup Database Configuration

Step 5: Create Mongoose Model

Step 6: Create Controllers

Step 7: Create Routes

Step 8: Create Error Middleware

Step 9: Run the Server

Diagram of the App Structure

Postman Setup

Postman Collection Setup

Other Articles

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Step 2: Setup `.env` File

Step 3: Create `server.js`