DialoGO - Backend

DialoGO is a complete chat platform built with the main goal of learning and deeply understanding WebSockets in real-time applications.

This repository contains the backend of the project, responsible for authentication, chat management, message handling, and real-time communication using Socket.IO.

The architecture follows a layered pattern (Controller → Service → Repository), ensuring separation of concerns, maintainability, data consistency, and security.

🚀 Technologies

• Node.js
• Express 5
• Socket.IO
• PostgreSQL
• JWT (jsonwebtoken)
• bcrypt
• dotenv
• pg

🏗 Architecture

The backend is structured using three main layers:

Controller Layer

Responsible for:

• Handling HTTP requests and responses
• Extracting parameters
• Returning proper status codes
• Delegating business logic to services

Service Layer

Responsible for:

• Business rules
• Validation
• Authorization checks
• Data normalization
• Coordinating repository calls

Repository Layer

Responsible for:

• Direct interaction with PostgreSQL
• SQL queries
• Returning structured data to services

This structure guarantees:

• Better scalability
• Cleaner code
• Easier testing
• Stronger separation of responsibilities

🔐 Authentication

DialoGO uses JWT-based authentication.

• Passwords are hashed using bcrypt
• Login generates a signed JWT token
• Protected routes use an authentication middleware
• Socket connections are authenticated using JWT
• The authenticated user is attached to the socket instance

💬 Real-Time Communication

Socket.IO is used to handle:

• Authenticated socket connections
• Chat room join/leave
• Real-time message broadcasting
• Emitting new messages to specific chat rooms

Each chat works as a socket room, ensuring proper message isolation and scalability.

🗄 Database

The project uses PostgreSQL.

Main concepts implemented in the schema:

• Users
• Chats
• Chat membership
• Messages
• Chat ownership
• Password-protected chats

The SQL schema is available in the db.sql file.

📦 Installation

1. Clone the repository

2. Install dependencies:

npm install

3. Create a PostgreSQL database

4. Run the SQL schema inside db.sql to create the tables

5. Create a .env file with the required environment variables:

PORT=3000
DATABASE_URL=your_postgres_connection_string
JWT_SECRET=your_secret_key
</code>

6. Start the development server:

npm run dev

📌 Notes

• The project uses ES Modules ("type": "module")
• Express 5 is used instead of Express 4
• The backend is designed to integrate with a frontend client
• All socket connections require valid JWT authentication

🔗 Frontend Application

The frontend application that consumes this API is available at:

https://github.com/DavidEricson00/DialoGO-Frontend