Bank ATM System

A full-stack banking application developed as part of the Software Development Project course.

This system simulates a real-world ATM environment consisting of:

The project demonstrates layered architecture, secure authentication, database transactions and full-stack integration.

Project Poster

Table of Contents

• Project Overview
• Project Poster
• System Architecture
• Project Goals
• Project Team
• Features Implemented
• Technologies Used
• Backend Setup
• Qt ATM Client
• Authentication Flow
• Test Credentials
• Documentation
• Project Management
• Security Considerations
• License

System Architecture

System Architecture

+----------------------+
|  Qt Desktop Client   |
|  (C++ / Qt Widgets)  |
+----------+-----------+
           |
           | HTTP (JSON, JWT)
           v
+----------------------+
|  Node.js REST API    |
|  (Express)           |
+----------+-----------+
           |
           | Stored Procedures
           v
+----------------------+
|  MySQL Database      |
+----------------------+

Communication Flow

1. Qt client sends HTTP request
2. REST API validates JWT and business rules
3. Stored procedure executes database logic
4. JSON response returned to client

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Project Goals

• Implement a layered backend architecture
• Design and implement a REST API
• Use stored procedures for database logic
• Implement authentication with JWT
• Create a working ATM UI in Qt
• Fulfill course minimum and advanced requirements

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Project Team

Name	Responsibilities
Juha Jermalainen	CRUD, Swagger, backend
Laura Similä	Backend, REST API, frontend
Arttu Jämsä	documentation, frontend, Qt
Valtteri Tenhunen	Image upload

(All members participated in planning, implementation and testing.)

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Features Implemented

Core Requirements (Grade 1–2)

• Debit account support
• Qt application startup user interface
• Card login with PIN verification
• Balance display
• Withdrawal (20€, 40€, 50€, 100€)
• 10 latest transactions
• 10-second PIN timeout
• Full CRUD operations for all database tables

Advanced Features (Grade 3–4)

• Credit account support
• Credit limit handling
• Withdrawal of any amount (only €20 and €50 notes at ATM)
• Persistent card locking (stored in database)
• 30-second global inactivity timeout
• Transaction history browsing (pagination)

Excellent-Level Features (Grade 5)

• Dual card support (debit + credit in one card)
• Account selection after login
• UML state diagram created
• Role-based authorization (admin / user)
• Structured API contract documentation
• Clean MVC-style backend structure
• Additional features:
  • Uploading and displaying images
  • Swagger documentation
  • Logs
  • Adding tests to the backend
  • CI/CD
  • Extra Qt application (admin)

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Technologies Used

Backend

• Node.js
• Express
• MySQL
• JWT authentication
• bcrypt (PIN hashing)
• Stored procedures
• Swagger documentation
• CI/CD

Frontend

• C++ (Qt Widgets)
• QNetworkAccessManager (API client)
• CMake build system

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Backend Setup

1. Install dependencies

cd backend
npm install

2. Create .env file

DB_HOST=localhost
DB_USER=root
DB_PASSWORD=your_password
DB_NAME=bank_db
DB_PORT=3306

JWT_SECRET=your-secret-key
PIN_PEPPER=your-pepper-value

PORT=3000

3. Initialize database

cd backend/db
mysql -u root -p bank_db < schema.sql
mysql -u root -p bank_db < procedures.sql
mysql -u root -p bank_db < seed.sql

4. Start backend (running in development)

cd backend
npm start

Backend runs at:

http://localhost:3000

Swagger documentation:

http://localhost:3000/docs

Production Deployment (PM2) & Process Management

Backend is managed using PM2 to ensure:

• Automatic restart on crashes
• Process monitoring
• Background execution
• Production-style process control

PM2 configuration:

• ecosystem.config.js

• Startup instructions documented in:

  SETUP_AUTOSTART.md

If deployed, backend can be started using:

pm2 start ecosystem.config.js

This setup enables production-style backend management and supports CI/CD workflows.

GitHub Actions CI/CD

The project includes CI configuration for backend and frontend.

Continuous Integration:

• Automatic build checks
• Linting
• Optional test execution

This ensures code quality and maintainability.

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Qt ATM Client

1. Open bank-automat in Qt Creator
2. Configure with CMake
3. Build and run

The client communicates with the backend using the REST API.

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Authentication Flow

1. User enters card ID and PIN
2. Backend validates PIN (bcrypt + pepper)
3. JWT token issued
4. Token stored in memory
5. Token sent in Authorization header
6. Account selected (if multiple)
7. ATM operations performed

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Test Credentials

Regular User

• Card: CARD123456
• PIN: 1234

Admin User

• Card: ADMINCARD
• PIN: admin123

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Documentation

REST API Contract

📄 API_CONTRACT_v2.md

Stored Procedures

📄 STORED_PROCEDURES.md

Backend Autostart (PM2)

📄 SETUP_AUTOSTART.md

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Project Management

• Git + GitHub version control
• Feature branches + Pull Requests
• Kanban board used for task management
• Weekly progress meetings
• Technical specification document created
• UML diagrams (ER, component, state diagram)

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Security Considerations

• PIN codes stored as bcrypt hashes
• Additional server-side pepper
• JWT authentication
• Role-based access control
• Database access only through stored procedures
• Server-side validation for all financial operations

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License

This project is developed for educational purposes.

MIT License can be applied if published publicly.

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