📇 Contact Management App

A simple Node.js + Express + MongoDB application for managing contacts with JWT authentication and user-based access control.

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🚀 Project Introduction

This project demonstrates how to build a REST API using Express with the following features:

• REST API convention (clear endpoints, CRUD structure)
• Contact management (CRUD)
• User authentication with JWT
• Route protection and role-based access
• MongoDB integration with Mongoose
• Error handling middleware and async handlers

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⚙️ Project Setup

1. Clone the repository

git clone <your-repo-url>
cd contact-management-app

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2. Install dependencies

npm install

3. Setup environment variables

Create a .env file in the root directory:

PORT=5000
MONGO_URI=your_mongodb_connection_string
JWT_SECRET=your_secret_key

4. Run the project

npm start

🛠 Features & Implementation

Express Setup

• Built an Express server
• Configured middleware for JSON parsing and error handling
• Used express.Router() for modular route management

Contacts CRUD

• GET /api/contacts → Fetch all contacts
• POST /api/contacts → Create a new contact
• GET /api/contacts/:id → Fetch a single contact by ID
• PUT /api/contacts/:id → Update a contact
• DELETE /api/contacts/:id → Delete a contact

Controllers

• Contact Controller → Handles CRUD logic for contacts
• User Controller → Handles registration, login, and current user retrieval

Middleware

• Custom error handling middleware
• Async handler (express-async-handler) for managing async/await
• JWT verification middleware (verifyJWT) for protecting routes

MongoDB & Mongoose

• Mongoose schema for Contact
• Mongoose schema for User with password hashing
• Established relationship between User and Contact

Authentication & Authorization

• User registration (/api/users/register)
• User login with JWT access token (/api/users/login)
• Route protection with JWT verification
• User-specific contacts → Only logged-in users can manage their own contacts

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Testing API

You can use Thunder Client (VS Code extension) or Postman:

1. Register a user → /api/users/register
2. Login with credentials → /api/users/login
   • Copy the JWT token
3. Add Authorization: Bearer <your_token> in headers
4. Access protected routes (Contacts CRUD)

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Learning Highlights

• Building an Express server
• REST API conventions
• Using routers for modular code
• Middleware for error handling and async requests
• MongoDB integration with Mongoose
• User authentication with JWT
• Protecting routes with middleware
• Relationship between users and contacts in MongoDB

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Tech Stack

• Node.js
• Express.js
• MongoDB + Mongoose
• JWT (jsonwebtoken)
• bcryptjs

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License

This project is for learning purposes and can be freely used or extended.