Authentication Service

A simple authentication service built with FastAPI and SQLite, providing JWT-based authentication for user signup, login, and logout functionality.

Features

• User registration (signup)
• User authentication (login)
• User logout
• JWT-based authentication
• Protected routes
• Health check endpoint
• SQLite database with SQLAlchemy ORM
• Database migrations with Alembic

Project Structure

.
├── alembic.ini                  # Alembic configuration
├── app                          # Application package
│   ├── api                      # API endpoints
│   │   └── endpoints.py         # Auth endpoints
│   ├── core                     # Core modules
│   │   ├── auth.py              # Auth utilities
│   │   ├── config.py            # App configuration
│   │   └── security.py          # Security utilities
│   ├── db                       # Database
│   │   ├── base.py              # Base DB imports
│   │   └── session.py           # DB session
│   ├── middleware               # Middleware
│   │   └── auth.py              # JWT middleware
│   ├── models                   # Database models
│   │   └── user.py              # User model
│   └── schemas                  # Pydantic schemas
│       ├── token.py             # Token schemas
│       └── user.py              # User schemas
├── init_db.py                   # DB initialization script
├── main.py                      # Application entry point
├── migrations                   # Alembic migrations
│   ├── env.py                   # Migration env
│   ├── script.py.mako           # Migration template
│   └── versions                 # Migration scripts
│       └── 001_create_users_table.py
└── requirements.txt             # Project dependencies

Installation

1. Clone the repository
2. Install dependencies:

pip install -r requirements.txt

3. Initialize the database:

python init_db.py

Running the Application

uvicorn main:app --reload

The application will be available at http://localhost:8000

API Documentation

Once the application is running, you can access:

• Swagger UI: http://localhost:8000/docs
• ReDoc: http://localhost:8000/redoc

API Endpoints

Authentication

• POST /api/v1/auth/signup - Create a new user
• POST /api/v1/auth/login - Login and get access token
• POST /api/v1/auth/logout - Logout (client-side token invalidation)

User

• GET /api/v1/users/me - Get current user information (protected)

Health Check

• GET /health - Check application health and database connectivity

Authentication Flow

1. Signup: Send a POST request to /api/v1/auth/signup with user information
2. Login: Send a POST request to /api/v1/auth/login to get an access token
3. Authenticated Requests: Include the token in the Authorization header as Bearer <token>
4. Logout: Client should remove the token from storage

Security

• Passwords are hashed using Bcrypt
• JWT tokens are used for authentication
• Token expiration is configurable in settings
• Protected routes are secured with OAuth2PasswordBearer dependency

Configuration

Configuration is handled through environment variables and the app/core/config.py file.

Important settings:

• SECRET_KEY: Used for JWT token signing (change in production)
• ACCESS_TOKEN_EXPIRE_MINUTES: Token expiration time
• SQLALCHEMY_DATABASE_URL: Database connection string