FastAPI 框架

精选 FastAPI 常用指令与核心速查备忘单，涵盖高频用法、配置参数与实用技巧。FastAPI 是一个快速、现代的 Python 3.7+ Web 框架，用于构建 API 的简明速查表。

Star 项目
关注 X (Twitter)
赞赏饮咖啡

#入门指南

#安装与运行 (Install & Run)

pip install fastapi uvicorn
uvicorn main:app --reload

#Hello World 示例

from fastapi import FastAPI
app = FastAPI()

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

#命令行运行提示 (CLI Run Hint)

uvicorn main:app --reload

#路由与参数

#路径参数 (Path Parameter)

@app.get("/items/{id}")
def read(id: int):
    return {"id": id}

#查询参数 (Query Parameter)

@app.get("/search")
def find(q: str = "default"):
    return {"q": q}

#可选查询参数 (可选 Query)

@app.get("/filter")
def filter_data(limit: int = 10, active: bool = True):
    return {"limit": limit, "active": active}

#请求体与验证

#使用 Pydantic (Using Pydantic)

from pydantic import BaseModel

class Item(BaseModel):
    name: str
    price: float

#JSON 请求体 (JSON Body)

@app.post("/items/")
def create(item: Item):
    return item

#响应模型 (Response Model)

@app.post("/items/", response_model=Item)
def create(item: Item):
    return item

#表单、文件与请求头

#表单输入 (Form Input)

from fastapi import Form

@app.post("/login")
def login(user: str = Form(...)):
    return {"user": user}

#文件上传 (File Upload)

from fastapi import UploadFile, File

@app.post("/upload")
def upload(f: UploadFile = File(...)):
    return {"filename": f.filename}

#请求头与 Cookies (Headers / Cookies)

from fastapi import Header, Cookie

@app.get("/info")
def info(ua: str = Header(None)):
    return {"UA": ua}

#中间件与依赖注入

#中间件 (Middleware)

@app.middleware("http")
async def log_req(req, call_next):
    res = await call_next(req)
    return res

#依赖注入 (Dependency)

from fastapi import Depends

def auth(token: str = ""):
    if token != "xyz": raise HTTPException(401)
    return True

@app.get("/secure")
def secure(_: bool = Depends(auth)):
    return {"secure": True}

#错误处理与 JSON API

#HTTP 错误 (HTTP Error)

from fastapi import HTTPException

@app.get("/err")
def error():
    raise HTTPException(404, "Not Found")

#JSON API 响应

from fastapi import FastAPI

@app.get("/json")
def get_data():
    return {"status": "ok"}

#模板与静态文件

#挂载静态文件 (Mount Static)

from fastapi.staticfiles import StaticFiles
app.mount("/static", StaticFiles(directory="static"), name="static")

#Jinja2 模板支持 (Jinja2 Support)

from fastapi.templating import Jinja2Templates
templates = Jinja2Templates("templates")

#路由器与项目结构

#路由器（类似蓝图）(Routers / Blueprints)

from fastapi import APIRouter
router = APIRouter()

@router.get("/")
def admin():
    return {"admin": True}

app.include_router(router, prefix="/admin")

#文件夹布局 (Folder Layout)

project/
├── main.py
├── static/
├── templates/
├── routers/
│   └── admin.py
└── models/

#文档与状态码

#内置文档 (Built-in Docs)

  • Swagger 文档: /docs
  • ReDoc 文档: /redoc

#自定义状态码 (Custom Status Code)

from fastapi import status

@app.post("/create", status_code=status.HTTP_201_CREATED)
def create():
    return {"msg": "Created"}