Building a backend notes app using Node.js, Express, and MongoDB can be a straightforward task. However, to ensure that your application remains maintainable, scalable, and testable, adopting a robust architecture is crucial. In this guide, we will focus on implementing a 3-layer architecture that separates concerns effectively, moving the business logic away from Express controllers into dedicated service classes. This approach prevents the pitfalls of spaghetti code and simplifies testing by decoupling the core business logic from the HTTP-specific request and response handling.
Traditionally, many developers lean towards the MVC (Model-View-Controller) pattern when structuring their applications. However, the MVC style often leads to controllers becoming bloated with business logic, making it harder to manage, especially as the application grows. In this architecture, we avoid putting business logic in controllers, thus maintaining a clear separation between different layers of the application.
The key benefits of this approach include:
- Separation of Concerns: By dividing the application into distinct layers (Controller, Service, and Model), each layer has a clear responsibility, making the code easier to understand and maintain.
- Testability: With business logic encapsulated in services, unit testing becomes straightforward. Services can be tested in isolation without needing to mock HTTP requests and responses.
- Scalability: This architecture supports better scalability as each layer can evolve independently. For example, changes in business logic don’t require modifications in the controller layer.
- Maintainability: Clean separation allows for easier debugging and enhances code readability, making maintenance less cumbersome.
Modules Overview
To build this application, we will divide the development process into several modules, each focusing on a specific aspect of the application. This modular approach ensures that we cover all essential parts systematically.
Module 1: Setup and Installation
In this module, we will install the necessary tools and dependencies, set up the project structure, and connect to GitHub using Visual Studio Code. We will also create documentation and draw the application schema/diagram to visualize the overall structure.
Module 2: Business Logic and Services
Here, we will focus on creating services that encapsulate the business logic. This module will demonstrate the core difference from the MVC style by highlighting how the business logic is decoupled from controllers and moved into service classes.
Module 3: Application Initialization
This module covers the initialization of the application, including setting up middleware, connecting to the database, and handling errors. It ensures that the application is ready to handle HTTP requests and perform CRUD operations.
Module 4: Advanced Features (Search, Filtering, Pagination)
In this module, we will enhance the functionality of the notes app by implementing features like search, filtering, and pagination. These features improve the user experience by allowing more flexible and efficient data retrieval.
Module 1: Amazing
Overview
In this module, we will set up the foundation of our notes application by installing the necessary tools, configuring the project structure, and preparing the environment. This includes installing Node.js, Express, MongoDB, and other dependencies, setting up configuration files, and connecting the project to GitHub using Visual Studio Code. We will also create documentation and an application schema to visualize the structure.
Steps
Install Node.js and npm: Ensure Node.js and npm are installed on your machine. These tools are essential for running JavaScript on the server and managing dependencies.
Initialize the Project: Create a new directory for your project and initialize it with npm to generate a
package.jsonfile. This file will keep track of your project’s dependencies and scripts.Install Dependencies: Install the necessary packages for the backend:
- Express: A web framework for Node.js to build our API.
- Mongoose: An ODM (Object Data Modeling) library for MongoDB and Node.js.
- Dotenv: For managing environment variables.
- Body-parser: Middleware to parse incoming request bodies.
- Express-async-errors: To handle errors in async routes.
Create Directory Structure: Organize your project into a structured directory layout to maintain a clear separation of concerns. This includes directories for configuration, controllers, models, routes, services, and utilities.
Environment Variables: Create a
.envfile to store configuration variables such as database connection strings and server port. This file should not be included in version control to keep sensitive information secure.Database Configuration: Set up a configuration file to connect to the MongoDB database using Mongoose. This will handle the connection logic and error handling for the database.
Application Schema/Diagram: Use a tool like draw.io or any preferred diagram software to create a schema or diagram of your application. This helps visualize the structure and flow of data within the application.
GitHub Integration:
- Initialize a Git Repository: Initialize a local Git repository in your project directory.
- Create a Remote Repository: Create a new repository on GitHub and link it to your local repository.
- Connect with Visual Studio Code: Use Visual Studio Code to manage your Git repository, stage changes, commit, and push to GitHub.
Detailed Steps
Install Node.js and npm: Download and install Node.js from the official website. Verify the installation by running:
node -v
npm -v
2. Initialize the Project: Open your terminal and run the following commands to create and initialize your project:
mkdir notes-app
cd notes-app
npm init -y
3. Install Dependencies: Install the required packages:
npm install express mongoose dotenv body-parser express-async-errors
4. Create Directory Structure: Organize your project as follows:
notes-app/
├── src/
│ ├── config/
│ │ └── db.js
│ ├── controllers/
│ │ └── noteController.js
│ ├── models/
│ │ └── Note.js
│ ├── routes/
│ │ └── noteRoutes.js
│ ├── services/
│ │ └── noteService.js
│ ├── utils/
│ │ └── errorHandler.js
│ ├── app.js
│ └── server.js
├── .env
├── package.json
└── README.md
Environment Variables: Create a .env file in the root directory with the following content:
PORT=3000
MONGODB_URI=mongodb://localhost:27017/notes-app
Database Configuration: Create a
db.jsfile in thesrc/config/directory to handle database connections.Application Schema/Diagram: Use a diagram tool to create a visual representation of your application architecture, including how data flows through different layers.
GitHub Integration:
- Initialize a Git repository
git init
git remote add origin <your-repository-url>
- Use Visual Studio Code to connect to GitHub:
- Open the project in Visual Studio Code.
- Use the Source Control panel to manage your repository.
- Use Visual Studio Code to connect to GitHub:
Documentation
Document each step and maintain a README.md file that includes:
- Project setup instructions.
- How to run the application.
- An overview of the project structure.
- Environment setup details.
By following these steps, you will have a well-structured foundation for your notes application, ready for further development in subsequent modules. This setup ensures that your project remains organized, maintainable, and scalable from the start.
Module 2: Business Logic and Services
In this module, we will focus on creating services that encapsulate the business logic of our notes application. This approach ensures that the business logic is decoupled from the controllers, maintaining a clear separation of concerns. The services will handle all the core functionalities related to notes, such as creating, retrieving, updating, and deleting notes. This modular design enhances testability, maintainability, and scalability.
Steps
Create Note Model: Define the schema for the notes stored in the MongoDB database using Mongoose.
Create Note Service: Develop a service class that includes methods for all CRUD operations (Create, Read, Update, Delete) on notes. This class will interact with the Note model to perform database operations.
Create Note Controller: Implement a controller that handles HTTP requests and delegates the business logic to the Note service. The controller will handle the request validation and response formatting.
Create Routes: Set up the routing for the notes API. These routes will link the HTTP endpoints to the controller methods.
Middleware and Error Handling: Implement middleware for error handling to ensure that any errors are caught and processed correctly, providing meaningful feedback to the client.
Detailed Steps
Create Note Model: In the
src/models/directory, create a file namedNote.jsto define the schema for the notes.
const mongoose = require('mongoose');
const noteSchema = new mongoose.Schema({
title: {
type: String,
required: true,
},
content: {
type: String,
required: true,
},
createdAt: {
type: Date,
default: Date.now,
},
});
module.exports = mongoose.model('Note', noteSchema);
2. Create Note Service: In the src/services/ directory, create a file named noteService.js and define the NoteService class.
const Note = require('../models/Note');
class NoteService {
async createNote(data) {
const note = new Note(data);
return await note.save();
}
async getAllNotes() {
return await Note.find();
}
async getNoteById(id) {
return await Note.findById(id);
}
async updateNote(id, data) {
return await Note.findByIdAndUpdate(id, data, { new: true });
}
async deleteNote(id) {
return await Note.findByIdAndDelete(id);
}
}
module.exports = new NoteService();
3. Create Note Controller: In the src/controllers/ directory, create a file named noteController.js to handle HTTP requests.
const noteService = require('../services/noteService');
exports.createNote = async (req, res) => {
try {
const note = await noteService.createNote(req.body);
res.status(201).json(note);
} catch (error) {
res.status(400).json({ error: error.message });
}
};
exports.getAllNotes = async (req, res) => {
try {
const notes = await noteService.getAllNotes();
res.status(200).json(notes);
} catch (error) {
res.status(400).json({ error: error.message });
}
};
exports.getNoteById = async (req, res) => {
try {
const note = await noteService.getNoteById(req.params.id);
if (!note) {
return res.status(404).json({ error: 'Note not found' });
}
res.status(200).json(note);
} catch (error) {
res.status(400).json({ error: error.message });
}
};
exports.updateNote = async (req, res) => {
try {
const note = await noteService.updateNote(req.params.id, req.body);
if (!note) {
return res.status(404).json({ error: 'Note not found' });
}
res.status(200).json(note);
} catch (error) {
res.status(400).json({ error: error.message });
}
};
exports.deleteNote = async (req, res) => {
try {
const note = await noteService.deleteNote(req.params.id);
if (!note) {
return res.status(404).json({ error: 'Note not found' });
}
res.status(200).json({ message: 'Note deleted' });
} catch (error) {
res.status(400).json({ error: error.message });
}
};
4. Create Routes: In the src/routes/ directory, create a file named noteRoutes.js to define the API endpoints.
const express = require('express');
const noteController = require('../controllers/noteController');
const router = express.Router();
router.post('/notes', noteController.createNote);
router.get('/notes', noteController.getAllNotes);
router.get('/notes/:id', noteController.getNoteById);
router.put('/notes/:id', noteController.updateNote);
router.delete('/notes/:id', noteController.deleteNote);
module.exports = router;
Middleware and Error Handling: In the src/utils/ directory, create a file named errorHandler.js for error handling middleware.
module.exports = (err, req, res, next) => {
console.error(err.stack);
res.status(500).json({ error: 'Something went wrong!' });
};
In this module, we have set up the core business logic for our notes application by creating a dedicated service layer. The NoteService class encapsulates all CRUD operations, and the controller handles HTTP requests, delegating business logic to the service. We have also set up routes to link HTTP endpoints to the controller methods and implemented middleware for error handling. This structured approach ensures that our codebase remains clean, maintainable, and testable.
Module 3: Application Initialization
In this module, we will initialize the application by setting up the middleware, connecting to the database, and configuring error handling. This step ensures that the application is ready to handle HTTP requests and perform CRUD operations. By the end of this module, we will have a running server that can interact with the MongoDB database and provide a RESTful API for managing notes.
Steps
Initialize Express App: Set up the main application file to initialize Express, configure middleware, and define the primary routes.
Database Connection: Establish a connection to the MongoDB database using Mongoose, ensuring the application can persist data.
Middleware Configuration: Configure necessary middleware for parsing JSON requests and handling errors.
Start the Server: Create a server file to start the Express application and listen for incoming requests.
Error Handling: Ensure the application has robust error handling to manage unexpected situations gracefully.
Detailed Steps
Initialize Express App: In the
src/directory, create a file namedapp.jsto set up the Express application.
const express = require('express');
const bodyParser = require('body-parser');
const noteRoutes = require('./routes/noteRoutes');
const errorHandler = require('./utils/errorHandler');
const connectDB = require('./config/db');
const app = express();
// Middleware to parse JSON requests
app.use(bodyParser.json());
// Routes
app.use('/api', noteRoutes);
// Error Handling Middleware
app.use(errorHandler);
// Connect to Database
connectDB();
module.exports = app;
Database Connection: Ensure you have a file named db.js in the src/config/ directory to handle the database connection.
const mongoose = require('mongoose');
const dotenv = require('dotenv');
dotenv.config();
const connectDB = async () => {
try {
await mongoose.connect(process.env.MONGODB_URI, {
useNewUrlParser: true,
useUnifiedTopology: true,
});
console.log('MongoDB connected');
} catch (error) {
console.error('Error connecting to MongoDB', error);
process.exit(1);
}
};
module.exports = connectDB;
Middleware Configuration: In
app.js, ensure middleware for parsing JSON and handling errors is configured as shown in the previous step.Start the Server: In the
src/directory, create a file namedserver.jsto start the Express server.
const app = require('./app');
const dotenv = require('dotenv');
dotenv.config();
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
console.log(`Server running on port ${PORT}`);
});
Error Handling: Ensure the error handling middleware in errorHandler.js is correctly set up to catch and respond to errors.
module.exports = (err, req, res, next) => {
console.error(err.stack);
res.status(500).json({ error: 'Something went wrong!' });
};
In this module, we have set up the core infrastructure for our notes application. We initialized the Express app, established a connection to the MongoDB database, and configured essential middleware for handling requests and errors. We also set up the server to listen for incoming requests. With these foundational elements in place, the application is now ready to handle CRUD operations and provide a robust API for managing notes.
Module 4: Advanced Features (Search, Filtering, Pagination)
Overview
In this module, we will enhance the functionality of our notes application by implementing advanced features such as search, filtering, and pagination. These features will allow users to efficiently retrieve and manage notes based on specific criteria and handle large sets of data more effectively.
Steps
Extend Note Service for Advanced Features: Update the service layer to include methods for searching, filtering, and paginating notes.
Update Controller for Advanced Features: Modify the controller to handle search, filtering, and pagination parameters from HTTP requests and pass them to the service layer.
Update Routes: Adjust the routing to support query parameters for search, filtering, and pagination.
Test the Advanced Features: Ensure that the advanced features work correctly by testing them using tools like Postman.
Detailed Steps
Extend Note Service for Advanced Features: In
src/services/noteService.js, update the NoteService class to include methods for search, filtering, and pagination.
const Note = require('../models/Note');
class NoteService {
async createNote(data) {
const note = new Note(data);
return await note.save();
}
async getAllNotes(query) {
const { page = 1, limit = 10, search } = query;
const filter = search ? { title: { $regex: search, $options: 'i' } } : {};
const notes = await Note.find(filter)
.skip((page - 1) * limit)
.limit(Number(limit));
const count = await Note.countDocuments(filter);
return { notes, totalPages: Math.ceil(count / limit), currentPage: page };
}
async getNoteById(id) {
return await Note.findById(id);
}
async updateNote(id, data) {
return await Note.findByIdAndUpdate(id, data, { new: true });
}
async deleteNote(id) {
return await Note.findByIdAndDelete(id);
}
}
module.exports = new NoteService();
Update Controller for Advanced Features: In src/controllers/noteController.js, modify the getAllNotes method to handle query parameters.
const noteService = require('../services/noteService');
exports.createNote = async (req, res) => {
try {
const note = await noteService.createNote(req.body);
res.status(201).json(note);
} catch (error) {
res.status(400).json({ error: error.message });
}
};
exports.getAllNotes = async (req, res) => {
try {
const result = await noteService.getAllNotes(req.query);
res.status(200).json(result);
} catch (error) {
res.status(400).json({ error: error.message });
}
};
exports.getNoteById = async (req, res) => {
try {
const note = await noteService.getNoteById(req.params.id);
if (!note) {
return res.status(404).json({ error: 'Note not found' });
}
res.status(200).json(note);
} catch (error) {
res.status(400).json({ error: error.message });
}
};
exports.updateNote = async (req, res) => {
try {
const note = await noteService.updateNote(req.params.id, req.body);
if (!note) {
return res.status(404).json({ error: 'Note not found' });
}
res.status(200).json(note);
} catch (error) {
res.status(400).json({ error: error.message });
}
};
exports.deleteNote = async (req, res) => {
try {
const note = await noteService.deleteNote(req.params.id);
if (!note) {
return res.status(404).json({ error: 'Note not found' });
}
res.status(200).json({ message: 'Note deleted' });
} catch (error) {
res.status(400).json({ error: error.message });
}
};
Update Routes: In src/routes/noteRoutes.js, ensure the routes can handle query parameters for searching, filtering, and pagination.
const express = require('express');
const noteController = require('../controllers/noteController');
const router = express.Router();
router.post('/notes', noteController.createNote);
router.get('/notes', noteController.getAllNotes);
router.get('/notes/:id', noteController.getNoteById);
router.put('/notes/:id', noteController.updateNote);
router.delete('/notes/:id', noteController.deleteNote);
module.exports = router;
Test the Advanced Features: Use a tool like Postman to test the new features. You can send GET requests with query parameters to test search, filtering, and pagination.
- Search:
GET /api/notes?search=keyword - Pagination:
GET /api/notes?page=2&limit=5 - Combined:
GET /api/notes?search=keyword&page=2&limit=5
- Search:
In this module, we enhanced our notes application by adding advanced features like search, filtering, and pagination. These features improve the user experience by allowing efficient retrieval and management of notes based on specific criteria. By extending the service layer and updating the controller and routes, we maintained a clean separation of concerns and ensured our application remains scalable and maintainable. Testing these features using tools like Postman ensures they work as expected and provides a robust API for managing notes.
Module 5: Validation and Error Handling
Overview
In this module, we will focus on implementing robust validation and error handling mechanisms to ensure the reliability and user-friendliness of our notes application. By validating incoming data and handling errors gracefully, we can prevent common issues and provide meaningful feedback to users.
Steps
Install Validation Library: Install a validation library such as
joito handle schema-based validation for our input data.Create Validation Middleware: Develop middleware functions to validate the incoming request data for creating and updating notes.
Update Controllers to Use Validation Middleware: Apply the validation middleware to the relevant routes to ensure data integrity before processing requests.
Enhance Error Handling Middleware: Improve the existing error handling middleware to provide more detailed and user-friendly error messages.
Detailed Steps
Install Validation Library: Install
joi, a powerful schema description and data validation library for JavaScript.
npm install joi
Create Validation Middleware: In the src/middleware/ directory, create a file named validationMiddleware.js to define the validation logic.
const Joi = require('joi');
const noteSchema = Joi.object({
title: Joi.string().min(3).max(30).required(),
content: Joi.string().min(5).required(),
});
const validateNote = (req, res, next) => {
const { error } = noteSchema.validate(req.body);
if (error) {
return res.status(400).json({ error: error.details[0].message });
}
next();
};
module.exports = validateNote;
Update Controllers to Use Validation Middleware: Apply the validation middleware to the routes that handle creating and updating notes. Update src/routes/noteRoutes.js.
const express = require('express');
const noteController = require('../controllers/noteController');
const validateNote = require('../middleware/validationMiddleware');
const router = express.Router();
router.post('/notes', validateNote, noteController.createNote);
router.put('/notes/:id', validateNote, noteController.updateNote);
router.get('/notes', noteController.getAllNotes);
router.get('/notes/:id', noteController.getNoteById);
router.delete('/notes/:id', noteController.deleteNote);
module.exports = router;
Enhance Error Handling Middleware: Update the src/utils/errorHandler.js file to provide more detailed error messages and handle different types of errors gracefully.
module.exports = (err, req, res, next) => {
console.error(err.stack);
if (err.name === 'ValidationError') {
return res.status(400).json({ error: err.message });
}
res.status(500).json({ error: 'Something went wrong!' });
};
In this module, we enhanced our notes application by implementing validation and improving error handling. We used the joi library to create robust validation schemas and middleware to ensure that incoming data meets the required criteria. By integrating this validation middleware into our routes, we ensure that only valid data is processed, thereby improving the application’s reliability. Additionally, we refined our error handling middleware to provide more meaningful and user-friendly error messages, enhancing the overall user experience and making the application more resilient to errors.
Module 6: Logging and Monitoring
Overview
In this module, we will set up logging and monitoring to ensure that we can effectively track the application’s behavior and performance. Logging helps in diagnosing issues and understanding the application’s flow, while monitoring provides insights into the application’s health and performance.
Steps
Install Logging Library: Install a logging library such as
winstonto manage and format logs efficiently.Set Up Logger: Configure the logger to capture different levels of log messages and output them to appropriate destinations.
Integrate Logger into the Application: Use the logger in various parts of the application to log important events and errors.
Set Up Monitoring: Integrate a monitoring tool like
PrometheusandGrafanaor use a service likeNew Relicto monitor application metrics.
Detailed Steps
Install Logging Library: Install
winston, a versatile logging library for Node.js.
npm install winston
Set Up Logger: In the src/utils/ directory, create a file named logger.js to configure the logger.
const { createLogger, format, transports } = require('winston');
const logger = createLogger({
level: 'info',
format: format.combine(
format.timestamp({ format: 'YYYY-MM-DD HH:mm:ss' }),
format.errors({ stack: true }),
format.splat(),
format.json()
),
defaultMeta: { service: 'notes-app' },
transports: [
new transports.File({ filename: 'logs/error.log', level: 'error' }),
new transports.File({ filename: 'logs/combined.log' }),
],
});
if (process.env.NODE_ENV !== 'production') {
logger.add(new transports.Console({
format: format.combine(
format.colorize(),
format.simple()
),
}));
}
module.exports = logger;
Integrate Logger into the Application: Use the logger in various parts of the application, including the controllers, services, and error handling middleware. Update the src/controllers/noteController.js and src/utils/errorHandler.js to include logging.
Update noteController.js:
const noteService = require('../services/noteService');
const logger = require('../utils/logger');
exports.createNote = async (req, res) => {
try {
const note = await noteService.createNote(req.body);
logger.info('Note created', { noteId: note._id });
res.status(201).json(note);
} catch (error) {
logger.error('Error creating note', { error: error.message });
res.status(400).json({ error: error.message });
}
};
exports.getAllNotes = async (req, res) => {
try {
const result = await noteService.getAllNotes(req.query);
logger.info('Fetched all notes', { count: result.notes.length });
res.status(200).json(result);
} catch (error) {
logger.error('Error fetching notes', { error: error.message });
res.status(400).json({ error: error.message });
}
};
// ... (Other methods with similar logging)
Update errorHandler.js:
const logger = require('./logger');
module.exports = (err, req, res, next) => {
logger.error('Unhandled error', { error: err.message, stack: err.stack });
res.status(500).json({ error: 'Something went wrong!' });
};
Set Up Monitoring: For monitoring, you can choose between self-hosted solutions like Prometheus and Grafana or managed services like New Relic. Below is a basic setup example using Prometheus and Grafana.
Install Prometheus: Follow the Prometheus installation guide to set up Prometheus on your server.
Node Exporter: Install Node Exporter to expose your Node.js application metrics to Prometheus.
npm install prom-client
Configure Prometheus: Update your prometheus.yml to scrape metrics from your Node.js application.
scrape_configs:
- job_name: 'node'
static_configs:
- targets: ['localhost:3000']
Expose Metrics in Node.js: Create a file metrics.js in src/utils/ to set up and expose metrics.
const client = require('prom-client');
const express = require('express');
const app = express();
const collectDefaultMetrics = client.collectDefaultMetrics;
collectDefaultMetrics({ timeout: 5000 });
app.get('/metrics', async (req, res) => {
res.set('Content-Type', client.register.contentType);
res.end(await client.register.metrics());
});
module.exports = app;
Integrate Metrics Endpoint: In src/server.js, add the metrics endpoint.
const app = require('./app');
const metricsApp = require('./utils/metrics');
const dotenv = require('dotenv');
dotenv.config();
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
console.log(`Server running on port ${PORT}`);
});
metricsApp.listen(3001, () => {
console.log('Metrics server running on port 3001');
});
Set Up Grafana: Follow the Grafana installation guide to set up Grafana and visualize your Prometheus metrics.
In this module, we have enhanced our notes application by integrating logging and monitoring. We set up the winston logger to capture and format log messages, which helps in diagnosing issues and understanding the application’s behavior. We also integrated Prometheus and Grafana for monitoring application metrics, providing insights into the application’s health and performance. These enhancements ensure that our application is not only reliable but also easier to maintain and scale.
Module 7: Amazing Security and Best Practices
Overview
In this final module, we will focus on implementing security measures and adhering to best practices to ensure that our notes application is secure and maintainable. This includes securing the application against common vulnerabilities, setting up proper environment management, and implementing best practices for code quality and performance.
Steps
Environment Management: Ensure sensitive information is managed securely using environment variables.
Security Measures: Implement security best practices to protect against common vulnerabilities such as SQL injection, XSS, and CSRF.
Code Quality: Set up tools and practices to maintain high code quality.
Performance Optimization: Implement strategies to optimize the performance of the application.
Documentation: Ensure comprehensive documentation for the application.
Detailed Steps
Environment Management: Ensure that sensitive information such as database connection strings and API keys are stored in environment variables and not hard-coded in the application.
- Use dotenv: Ensure the use of the
.envfile for environment variables as previously set up. - Environment Configuration: Verify that
.envis included in.gitignoreto prevent it from being pushed to version control.
- Use dotenv: Ensure the use of the
Security Measures: Implement various security best practices and use security-related middleware.
Helmet Middleware: Install and use
helmetto set various HTTP headers for security.
npm install helmet
const helmet = require('helmet');
app.use(helmet());
CORS: Use cors to handle Cross-Origin Resource Sharing.
npm install cors
const cors = require('cors');
app.use(cors());
Input Sanitization: Use express-validator to sanitize and validate input data.
npm install express-validator
const { body, validationResult } = require('express-validator');
const validateNote = [
body('title').isString().trim().isLength({ min: 3 }).escape(),
body('content').isString().trim().isLength({ min: 5 }).escape(),
(req, res, next) => {
const errors = validationResult(req);
if (!errors.isEmpty()) {
return res.status(400).json({ errors: errors.array() });
}
next();
},
];
module.exports = validateNote;
Rate Limiting: Use express-rate-limit to limit repeated requests to public APIs and endpoints.
npm install express-rate-limit
const rateLimit = require('express-rate-limit');
const limiter = rateLimit({
windowMs: 15 * 60 * 1000, // 15 minutes
max: 100, // limit each IP to 100 requests per windowMs
});
app.use(limiter);
Code Quality: Set up tools and practices to maintain high code quality.
ESLint: Use ESLint for linting JavaScript code.
npm install eslint --save-dev
npx eslint --init
Prettier: Use Prettier for code formatting.
npm install prettier --save-dev
Create a .prettierrc file:
{
"singleQuote": true,
"trailingComma": "all"
}
Scripts: Add linting and formatting scripts to package.json.
"scripts": {
"lint": "eslint .",
"format": "prettier --write ."
}
Performance Optimization: Implement strategies to optimize the performance of the application.
Compression: Use
compressionmiddleware to gzip responses.
npm install compression
const compression = require('compression');
app.use(compression());
Database Indexing: Ensure appropriate indexes are set up in MongoDB for commonly queried fields.
const noteSchema = new mongoose.Schema({
title: {
type: String,
required: true,
},
content: {
type: String,
required: true,
},
createdAt: {
type: Date,
default: Date.now,
},
});
noteSchema.index({ title: 1, createdAt: -1 });
Documentation: Ensure comprehensive documentation for the application.
- API Documentation: Use tools like Swagger or Postman to document the API endpoints.
- README: Maintain a detailed
README.mdfile with setup instructions, usage examples, and contribution guidelines.
Example README Structure:
.
# Notes Application
## Overview
A simple notes application built with Node.js, Express, and MongoDB.
## Setup
1. Clone the repository.
2. Run `npm install` to install dependencies.
3. Create a `.env` file based on the example provided.
4. Run `npm start` to start the application.
## API Endpoints
- `POST /api/notes`: Create a new note.
- `GET /api/notes`: Get all notes.
- `GET /api/notes/:id`: Get a note by ID.
- `PUT /api/notes/:id`: Update a note by ID.
- `DELETE /api/notes/:id`: Delete a note by ID.
## Contributing
Contributions are welcome! Please fork the repository and submit a pull request.
In this module, we ensured that our notes application adheres to security best practices, maintains high code quality, and performs efficiently. By managing environment variables securely, implementing security measures, optimizing performance, and maintaining comprehensive documentation, we have built a robust and professional-grade application. These final steps ensure that the application is ready for production use and easy to maintain and extend in the future.
