🚀 FastAPI: A High - Performance Web Framework

FastAPI is a high - performance web application framework built on Python 3.5+ and Pydantic v1.x. It combines the best practices of modern web development with the concept of rapid development, aiming to help developers efficiently build RESTful APIs and real - time web applications.

✨ Features

High Performance: FastAPI uses the async/await asynchronous programming model, making it easy to handle high - concurrency requests.
Easy to Use: Through Pydantic models and Python type hints, you can quickly define the request and response structures of the API.
Automatic Documentation: It comes with built - in Swagger UI and ReDoc, generating interactive API documentation without additional configuration.
Scalability: Supports middleware, custom routes, and plugins, facilitating functional expansion.

📦 Installation

To start using FastAPI, you first need to install the necessary dependencies:

pip install fastapi[all]

This will install FastAPI and all its dependencies, including Pydantic and Starlette.

💻 Usage Examples

Basic Usage

Create a simple FastAPI application:

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
async def root():
    return {"message": "Hello World"}

Run the application:

uvicorn main:app --reload

Then, visit http://localhost:8000 in your browser, and you can see the automatically generated Swagger UI.

Advanced Usage

Path Parameters

@app.get("/items/{item_id}")
async def read_item(item_id: str):
    return {"item_id": item_id}

Visiting http://localhost:8000/items/5 will return {"item_id": "5"}.

Query Parameters

@app.get("/items")
async def read_items(q: str = None):
    if q:
        return {"q": q}
    else:
        return {"message": "No query string received"}

Visiting http://localhost:8000/items?q=hello will return {"q": "hello"}.

Request Body Parameters

from typing import Optional
import json

@app.post("/items")
async def create_item(data: dict):
    return data

Send a POST request to /items with the following request body:

{
    "name": "item1",
    "price": 10.5
}

It will return the same JSON data.

Middleware

FastAPI allows you to add middleware to extend functionality. For example, you can add a logging middleware:

@app.middleware("http")
async def log_request(request, call_next):
    print(f"Request received: {request.url}")
    response = await call_next(request)
    print(f"Response sent: {response.status_code}")
    return response

Automatic Documentation

FastAPI has built - in Swagger and ReDoc, which are convenient for developers to test and view API documentation. Visiting http://localhost:8000/docs will show you the interactive Swagger UI. Visiting http://localhost:8000/redoc will show you more detailed ReDoc documentation.

📚 Documentation

FastAPI is a powerful and easy - to - use web framework, suitable for quickly developing high - performance RESTful APIs and real - time web applications. With its built - in documentation generation and asynchronous support, developers can efficiently build and deploy web applications.