E-Commerce Chat Backend

A scalable, real-time chat backend built for e-commerce platforms using Node.js, Express, MongoDB, and Socket.IO.

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Features

• JWT-based user authentication (signup/login)
• Real-time messaging with Socket.IO
• Typing indicators and presence (online/offline)
• Message read receipts
• Conversation creation and retrieval
• File attachments support (Multer)
• Notification model and real-time notifications
• Modular codebase suitable for scaling

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Tech Stack

• Node.js + Express
• MongoDB with Mongoose
• Socket.IO for real-time communication
• JWT for auth
• Multer for file uploads
• Helmet, CORS, Morgan for security and logging

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Quick Start

1. Clone the repo and install dependencies

git clone https://github.com/yourusername/ecommerce-chat-backend.git
cd ecommerce-chat-backend
npm install

2. Create a .env in the project root with at least:

PORT=4000
MONGODB_URI=your_mongo_connection_string
JWT_SECRET=your_jwt_secret
CORS_ORIGIN=http://localhost:5173

3. Start the development server

npm run dev

Server will be available at http://localhost:4000 (adjust PORT as needed).

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API Reference

All API routes are namespaced under /api.

Authentication

• POST /api/auth/signup — Register a user (returns JWT)
• POST /api/auth/login — Login user (returns JWT)

Conversations

• POST /api/conversations — Create or fetch an existing conversation
• GET /api/conversations — Get conversations for the authenticated user

Messages

• POST /api/messages — Send a message. Body should include conversationId, senderId, text (and optional attachment).
• GET /api/messages/:conversationId — Fetch messages for a conversation

Notifications

• GET /api/notifications — Retrieve user notifications

Notes

• Protected endpoints require the Authorization header: Authorization: Bearer <token>

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Socket.IO Events

Connect to the same origin as the API (e.g., http://localhost:4000). The server emits and listens to events used by the frontend.

Client -> Server

• register — payload: userId (register socket id for the user)
• sendMessage — payload: { conversationId, senderId, recipientId, text, attachment? }
• typing / stopTyping — payload: { conversationId, senderId, recipientId }
• markRead — payload: { conversationId, userId, recipientId }

Server -> Client

• message — emitted to recipient(s) when a new message arrives
• typing / stopTyping — relays typing state
• notification — emitted for new notifications
• presence — updates online/offline status

Testing tip: use a Socket.IO client or the Socket.IO Tester extension to emit events and listen for responses.

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Environment & Configuration

• Keep secrets out of version control: use .env and a secrets manager in production.
• Recommended env entries: PORT, MONGODB_URI, JWT_SECRET, CORS_ORIGIN.

Optional production additions

• REDIS_URL for Socket.IO adapter in clustered environments
• NODE_ENV=production
• Logging DSN for monitoring (Sentry, Loggly, etc.)

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Best Practices & Production Recommendations

• Use HTTPS and HSTS in production.
• Run behind a reverse proxy (NGINX) or cloud load balancer.
• Use a process manager like PM2 or run as containers orchestrated by Kubernetes.
• Enable a Socket.IO adapter (Redis) when running multiple instances.
• Add request / schema validation (Joi or express-validator) where missing.
• Add rate limiting and input sanitization to prevent abuse.
• Add unit and integration tests for controllers and socket handlers.
• Add structured logging (Winston) and error monitoring (Sentry).

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Project Structure

src/
├── app.js                  # Express app configuration (middleware, routes)
├── server.js               # HTTP + Socket.IO bootstrap
├── config/
│   ├── db.js               # MongoDB connection helper
│   └── upload.js           # Multer upload configuration
├── controllers/            # Route handlers and business logic
├── middleware/             # Auth and error-handling middleware
├── models/                 # Mongoose models: User, Conversation, Message, Notification
├── routes/                 # Express route definitions
├── socket/                 # Socket.IO event handlers and helpers
├── utils/                  # Helpers (token generation, notifications)
└── uploads/                # Uploaded files (served statically)

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How to Test Locally

• Ensure MongoDB is reachable (local or cloud).
• Use Postman for REST APIs and a Socket.IO client to test real-time events.
• Example: create two users, register both sockets, then emit sendMessage from one to the other and observe the message event.

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Next Steps / Suggested Improvements

• Add automated tests (Jest + Supertest) for API and socket flows.
• Add CI (GitHub Actions) to run tests and lint on PRs.
• Add Dockerfile and docker-compose for local dev and production deployments.
• Integrate Redis adapter for Socket.IO to support horizontal scaling.
• Harden security headers and CSP for production.

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License

This project is licensed under the MIT License.