Before diving into code, let's understand the "why." FastAPI solves three fundamental problems that plagued previous Python frameworks like Flask and Django (for API development):
def common_parameters(q: str = None, skip: int = 0, limit: int = 10):return "q": q, "skip": skip, "limit": limit
@app.get("/items/") async def read_items(commons: dict = Depends(common_parameters)): return commons
my_fastapi_app/ │ ├── database.py ├── models.py ├── schemas.py ├── crud.py └── main.py Use code with caution. Configuration Files database.py
The docs live in the docs/en/ folder. They are Markdown files.
from pydantic import BaseModel, EmailStr class UserBase(BaseModel): email: EmailStr class UserCreate(UserBase): password: str class UserResponse(UserBase): id: int is_active: bool class Config: orm_mode = True Use code with caution. crud.py Handles database queries and operations.
python -m venv fastapi-env source fastapi-env/bin/activate # On Windows: fastapi-env\Scripts\activate pip install fastapi uvicorn
FastAPI leverages Python type hints to parse, validate, and document incoming requests. Path Parameters
The official docs at fastapi.tiangolo.com are markdown-based. You can clone the GitHub repository and use mkdocs build to generate a standalone site, then print-to-PDF using browser tools.
import time from fastapi import Request @app.middleware("http") async def add_process_time_header(request: Request, call_next): start_time = time.time() response = await call_next(request) process_time = time.time() - start_time response.headers["X-Process-Time"] = str(process_time) return response Use code with caution. Cross-Origin Resource Sharing (CORS)