FastAPI 完全指南：Python 现代高性能 Web 框架

from fastapi import FastAPI
import asyncio

app = FastAPI()

# 异步路径操作
@app.get("/async-data")
async def get_async_data():
    # 使用 await 进行异步操作
    data = await fetch_data_from_api()
    return data

# 同步路径操作（也可以）
@app.get("/sync-data")
def get_sync_data():
    data = fetch_data_sync()
    return data

async def fetch_data_from_api():
    await asyncio.sleep(1)  # 模拟异步 IO
    return {"message": "异步获取的数据"}

def fetch_data_sync():
    time.sleep(1)  # 模拟同步 IO
    return {"message": "同步获取的数据"}

from fastapi import FastAPI
from pydantic import BaseModel
from typing import Optional, List

app = FastAPI()

# 定义数据模型
class User(BaseModel):
    name: str
    email: str
    age: Optional[int] = None
    tags: List[str] = []

# 类型提示的路径参数
@app.get("/users/{user_id}")
async def get_user(user_id: int) -> User:
    return User(
        name="张三",
        email="zhangsan@example.com",
        age=25,
        tags=["developer", "python"]
    )

# 请求体
@app.post("/users")
async def create_user(user: User) -> User:
    # 自动验证数据类型
    return user

from fastapi import FastAPI

app = FastAPI(
    title="我的 API",
    description="这是一个示例 API",
    version="1.0.0"
)

@app.get("/items/{item_id}")
async def read_item(item_id: int, q: str | None = None):
    """
    读取项目

    - **item_id**: 项目 ID
    - **q**: 可选的查询参数
    """
    if q:
        return {"item_id": item_id, "q": q}
    return {"item_id": item_id}

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr, Field, validator

app = FastAPI()

class UserCreate(BaseModel):
    username: str = Field(..., min_length=3, max_length=50)
    email: EmailStr  # 自动验证邮箱格式
    password: str = Field(..., min_length=8)
    age: int = Field(ge=0, le=150)  # 年龄范围验证

    @validator('password')
    def password_strength(cls, v):
        if not any(c.isupper() for c in v):
            raise ValueError('密码必须包含大写字母')
        if not any(c.isdigit() for c in v):
            raise ValueError('密码必须包含数字')
        return v

@app.post("/users/")
async def create_user(user: UserCreate):
    return {"username": user.username, "email": user.email}

from fastapi import FastAPI, Depends, HTTPException
from typing import Annotated

app = FastAPI()

# 模拟数据库
fake_db = {"alice": {"email": "alice@example.com"}}

# 定义依赖
async def get_current_user(token: str = Depends(lambda: "current_user")):
    if token != "valid_token":
        raise HTTPException(status_code=401, detail="未授权")
    return {"username": "alice", "email": "alice@example.com"}

# 使用依赖
@app.get("/profile")
async def get_profile(user: dict = Depends(get_current_user)):
    return user

# 类作为依赖
class QueryParams:
    def __init__(self, q: str = "default", skip: int = 0, limit: int = 10):
        self.q = q
        self.skip = skip
        self.limit = limit

@app.get("/items")
async def read_items(params: QueryParams = Depends(QueryParams)):
    return {"q": params.q, "skip": params.skip, "limit": params.limit}

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

app = FastAPI()

# CORS 中间件
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

@app.middleware("http")
async def add_header(request, call_next):
    response = await call_next(request)
    response.headers["X-Custom-Header"] = "FastAPI"
    return response

# 数据库
pip install sqlalchemy
pip install databases
pip install sqlmodel

# 认证
pip install python-jose[cryptography]
pip install passlib[bcrypt]

# 验证
pip install email-validator

# 异步
pip install uvicorn[standard]
pip install httpx