Simple Users API with FastAPI & SQLite

FastAPi CRUD project is a RESTful API for managing users, built using FastAPI, SQLAlchemy, and SQLite. It demonstrates clean architecture, dependency injection, and best practices for Python web APIs.

Features

• List all users
• Add new users
• Update existing users
• Delete users
• Uses SQLite for persistent storage
• Pydantic models for data validation
• SQLAlchemy for ORM and database operations

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Project Structure

├── app/
│   ├── main.py          # FastAPI app entrypoint
│   ├── database.py      # DB engine & session setup
│   ├── models.py        # SQLAlchemy & Pydantic models
│   └── routes/
│       └── users.py     # User CRUD endpoints
├── users.db             # SQLite database file
├── requirements.txt     # Python dependencies
├── api_venv/            # Virtual environment
└── README.md            # Project documentation

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Step-by-Step Setup & Usage

1. Clone the Repository

git clone <your-repo-url>
cd "Public Api"

2. Create & Activate Virtual Environment

python -m venv api_venv
api_venv\Scripts\Activate.ps1

3. Install Dependencies

pip install -r requirements.txt

4. Run the API Server

uvicorn app.main:app --reload

The server will start at http://127.0.0.1:8000/

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API Endpoints & Usage

1. List All Users

Request:

curl -X GET "http://127.0.0.1:8000/users/" -H "accept: application/json"

Response:

[
   {"id": 1, "name": "gg", "email": "gg@example.com"},
   {"id": 2, "name": "kk", "email": "kk@example.com"}
]

2. Add a New User

Request:

curl -X POST "http://127.0.0.1:8000/users/" \
       -H "accept: application/json" \
       -H "Content-Type: application/json" \
       -d '{"id": 3, "name": "cc", "email": "cc@example.com"}'

Response:

{
   "message": "User added successfully",
   "user": {"id": 3, "name": "cc", "email": "cc@example.com"}
}

3. Update a User

Request:

curl -X PUT "http://127.0.0.1:8000/users/3" \
       -H "accept: application/json" \
       -H "Content-Type: application/json" \
       -d '{"id": 3, "name": "ccb", "email": "ccb@example.com"}'

Response:

{
   "message": "User updated successfully",
   "user": {"id": 3, "name": "ccb", "email": "ccb@example.com"}
}

4. Delete a User

Request:

curl -X DELETE "http://127.0.0.1:8000/users/3" -H "accept: application/json"

Response:

{
   "message": "User deleted successfully"
}

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How It Works

• FastAPI provides automatic OpenAPI docs at /docs and /redoc.
• SQLAlchemy manages the SQLite database and user table.
• Pydantic validates request and response data.
• Dependency Injection is used for database sessions.

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Troubleshooting

• If you get a 500 Internal Server Error, check that users.db exists and is writable.
• Ensure all dependencies are installed and the virtual environment is activated.
• For database schema changes, delete users.db and restart the server to recreate tables.

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