🚀 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.







