movassaghi6 / shopping-cart

a CRUD RESTful API with Python, FastAPI, SQLAlchemy ORM, Pydantic, PostgreSQL, and Docker-compose

shopping-cart

a CRUD RESTful API with Python, FastAPI, SQLAlchemy ORM, Pydantic, PostgreSQL, and Docker-compose

Introduction

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints.

The key features that I like in FastApi are:

• Fast to code: Increase the speed to develop features by about 200% to 300%. *
• Fewer bugs: Reduce about 40% of human (developer) induced errors. *
• Easy: Designed to be easy to use and learn. Less time reading docs.
• Robust: Get production-ready code. With automatic interactive documentation.
• Standards-based: Based on (and fully compatible with) the open standards for APIs: OpenAPI (previously known as Swagger) and JSON Schema.

Getting Started

To get started make sure the following requirements (for development and deployment tooling) are installed on your system:

• Python 3.11+ (Project Programming Language)
• Virtualenv (Python Dependency Manager)
• Docker (Containerization)
• Docker Compose (Composer for Docker)

To getting started with deployment:

1.You have to implement .env file in the root of project but what is the structure of this file:

# These credentials will be used by the Postgres Docker image to configure the PostgreSQL database.
DATABASE_PORT=6500
POSTGRES_PASSWORD=examplepassword
POSTGRES_USER=exampleusername
POSTGRES_DB=examplename
POSTGRES_HOST=examplehostname
POSTGRES_HOSTNAME=127.0.0.1

2.run following command to build docker image and start container:

docker-compose up -d

3.create python virtualenv

python3 -m venv venv

4.active python virtualenv

5.install packages

pip install -r requirements.txt

6.run project

uvicorn main:app --reload

7. now go to:

http://localhost:8000/docs

Endpoints

A basic shopping cart application has features such as Cart functionalities and Admin CRUD capabilities among other functionalities.

We have the following API's:

A few assumptions

You have a good understanding of Python Language The project you want to use this codebase for uses an SQL Database You have an understanding of sqlalchemy as an ORM The Repository contains 5 main files namely:

main.py

This file is the entry point for the application. It contains the main routes and redirects all requested routes to their respective functions.

crud.py

This file contains the main functions that interact with the database, it is basically where the business logic happens.

models.py

This file is similar to the one in Django. In this file is where we define our database tables.

schemas.py

This file contains the data schemas for our application.

database.py

This file contains our database connection string.

Code Samples

Just to show you how the flow works here is the working example of the get_item/id endpoint.

main.py

@app.get("/carts/{cart_id}", response_model=schemas.Cart)
def read_cart(cart_id: int, db: Session = Depends(get_db)):
    db_cart = crud.get_cart(db, cart_id= cart_id)
    if db_cart is None:
        raise HTTPException(status_code=404, detail="Cart not found")
    return db_cart

The above piece of code handles the endpoint and calls the function get_item_by_id in the crud.py file for further processing.

crud.py

def get_cart(db: Session, cart_id: int):
    return db.query(models.Cart).filter(models.Cart.id == cart_id).first()

The above piece of code handles the get_cart call and queries the DB for an item with the id passed in the parameter.

Todo

• Add support for user registeration and logging
• add testing
• Implement better error handling
• Implement incomplete endpoints