Kasir API Python

A Point of Sale (Kasir) REST API built with FastAPI and PostgreSQL.

Tech Stack

• Language: Python 3.14+
• Framework: FastAPI
• Database: PostgreSQL via psycopg (async)
• Validation: Pydantic
• Package Manager: uv

Features

• Health check endpoint
• Categories CRUD operations
• Products CRUD operations
• Async database operations
• Auto-generated API documentation

Quick Start

Prerequisites

• Python 3.14+
• uv package manager
• PostgreSQL database

Installation

1. Clone the repository:

   git clone <repository-url>
   cd kasir-api-python

2. Copy environment file and configure:

   cp .env.example .env

3. Edit .env and set your database connection string:

   DB_CONN=postgresql://user:password@localhost:5432/kasir_db
   PORT=8000
   

4. Install dependencies:

   uv sync

5. Run the development server:

   uv run fastapi dev src/kasir_api/app.py

   For production:

   uv run fastapi run src/kasir_api/app.py --port 8000

Environment Variables

Variable	Required	Default	Description
DB_CONN	Yes	-	PostgreSQL connection string
PORT	No	8000	Server port

API Endpoints

Method	Endpoint	Description
GET	/api/health	Health check
GET	/api/categories	Get all categories
GET	/api/categories/{id}	Get category by ID
POST	/api/categories	Create category
PUT	/api/categories/{id}	Update category
DELETE	/api/categories/{id}	Delete category
GET	/api/products	Get all products
GET	/api/products/{id}	Get product by ID
POST	/api/products	Create product
PUT	/api/products/{id}	Update product
DELETE	/api/products/{id}	Delete product

API Documentation

Once the server is running, access the interactive API documentation:

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

Project Structure

src/kasir_api/
├── app.py                    # FastAPI application entry point
├── config.py                 # Environment variable loading
├── settings.py               # Settings class
├── errors.py                 # Custom exception classes
├── lifespan.py               # Application lifespan management
├── models/                   # Pydantic models
│   ├── category.py
│   ├── health.py
│   └── product.py
├── repositories/             # Database access layer
│   ├── db.py
│   ├── category_repository.py
│   ├── health_repository.py
│   └── product_repository.py
├── services/                 # Business logic layer
│   ├── category_service.py
│   ├── health_service.py
│   └── product_service.py
└── handlers/                 # Request handlers (routes)
    ├── category_handler.py
    ├── health_handler.py
    └── product_handler.py

Testing

# Run all tests
uv run pytest

# Run with verbose output
uv run pytest -v

# Run with coverage
uv run pytest --cov=src/kasir_api