App Gastos BA - Backend API

A comprehensive expense management backend API built with Node.js, Express, and Sequelize. This application provides a robust REST API for managing personal and business expenses with features like user authentication, expense tracking, categorization, and AI-powered expense extraction from text.

🚀 Features

• User Authentication: Secure user registration and login with JWT tokens
• Expense Management: Full CRUD operations for expense tracking
• Multi-Currency Support: Support for different currencies
• Payment Methods: Track various payment methods
• Transaction Types: Categorize transactions (income/expense)
• Expense Categories: Organize expenses by categories
• AI-Powered Text Processing: Extract expense details from natural language using OpenAI
• Database Support: MySQL, PostgreSQL, and SQLite support
• RESTful API: Clean and intuitive API endpoints

🛠️ Tech Stack

• Runtime: Node.js
• Framework: Express.js
• Database ORM: Sequelize
• Database: MySQL/PostgreSQL/SQLite
• Authentication: JWT (JSON Web Tokens)
• Password Hashing: bcrypt
• AI Integration: OpenAI API
• File Upload: Multer
• Validation: Joi
• CORS: Cross-Origin Resource Sharing enabled

📋 Prerequisites

• Node.js (v14 or higher)
• npm or yarn
• MySQL/PostgreSQL database (or SQLite for development)
• OpenAI API key (for AI features)

🔧 Installation

1. Clone the repository

   git clone <repository-url>
   cd app-gastos-ba
   

2. Install dependencies

   npm install
   

3. Environment Configuration Create a .env file in the root directory:

   PORT=4000
   DB_HOST=localhost
   DB_USER=your_username
   DB_PASS=your_password
   DB_NAME=projectgastos
   DB_DIALECT=mysql
   JWT_SECRET=your_jwt_secret_key
   OPENAI_API_KEY=your_openai_api_key
   OPENAI_MODEL=gpt-3.5-turbo
   

4. Database Setup

   • For MySQL: Run the SQL script in src/database/db.sql
   • For PostgreSQL: Modify the script accordingly
   • For SQLite: The database will be created automatically

5. Start the application

   # Development mode with auto-reload
   npm run dev
   
   # Production mode
   npm start
   

The server will start on http://localhost:4000

📚 API Documentation

Authentication Endpoints

Register User

POST /api/register
Content-Type: application/json

{
  "username": "user123",
  "password": "password123",
  "email": "[email protected]"
}

Login

POST /api/login
Content-Type: application/json

{
  "username": "user123",
  "password": "password123"
}

Expense Management

Get All Expenses

GET /api/gastos?usuario_id=1&descripcion=groceries
Authorization: Bearer <jwt_token>

Create Expense

POST /api/gastos
Content-Type: application/json
Authorization: Bearer <jwt_token>

{
  "descripcion": "Grocery shopping",
  "monto": 150.50,
  "fecha": "2024-01-15",
  "divisa_id": 1,
  "tipostransaccion_id": 1,
  "metodopago_id": 1,
  "categoria_id": 1,
  "usuario_id": 1
}

Update Expense

PUT /api/gastos/:id
Content-Type: application/json
Authorization: Bearer <jwt_token>

{
  "monto": 160.00,
  "descripcion": "Updated grocery shopping"
}

Delete Expense

DELETE /api/gastos/:id
Authorization: Bearer <jwt_token>

AI-Powered Text Processing

Extract Expense from Text

POST /api/audio
Content-Type: application/json
Authorization: Bearer <jwt_token>

{
  "texto": "I spent $50 on groceries yesterday using my credit card",
  "usuario_id": 1
}

Master Data Endpoints

Categories

GET /api/categorias
POST /api/categorias
PUT /api/categorias/:id
DELETE /api/categorias/:id

Currencies

GET /api/divisas
POST /api/divisas
PUT /api/divisas/:id
DELETE /api/divisas/:id

Payment Methods

GET /api/metodosPagos
POST /api/metodosPagos
PUT /api/metodosPagos/:id
DELETE /api/metodosPagos/:id

Transaction Types

GET /api/tiposTransacciones
POST /api/tiposTransacciones
PUT /api/tiposTransacciones/:id
DELETE /api/tiposTransacciones/:id

🗄️ Database Schema

The application uses the following main tables:

• usuarios: User accounts and authentication
• gastos: Main expense records
• categorias: Expense categories
• divisas: Supported currencies
• metodospagos: Payment methods
• tipostransacciones: Transaction types (income/expense)

🔐 Security Features

• Password hashing with bcrypt
• JWT-based authentication
• Input validation with Joi
• CORS protection
• SQL injection prevention through Sequelize ORM

🤖 AI Integration

The application integrates with OpenAI's GPT models to:

• Extract expense details from natural language text
• Automatically categorize expenses
• Identify amounts, currencies, and payment methods
• Generate expense descriptions

🚀 Development

Project Structure

app-gastos-ba/
├── app.js                 # Main application file
├── package.json           # Dependencies and scripts
├── src/
│   ├── models/           # Sequelize models
│   ├── routes/           # API route handlers
│   ├── database/         # Database schema
│   └── security/         # Authentication middleware
└── assets/               # Static assets

Available Scripts

• npm run dev: Start development server with nodemon
• npm start: Start production server
• npm test: Run tests (to be implemented)

🤝 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

📄 License

This project is licensed under the ISC License.

🆘 Support

For support and questions, please open an issue in the repository or contact the development team.

🔄 Version History

• v1.0.0: Initial release with basic expense management and AI integration