FastAPI路由与请求处理全解：手把手打造用户管理系统 🔌

from fastapi import FastAPI

app = FastAPI()


# 简单GET路由
@app.get("/menu")
async def get_menu():
    return {"饮品": ["美式", "拿铁", "卡布奇诺"]}


# 带路径参数的GET路由
@app.get("/orders/{order_id}")
async def get_order(order_id: int):
    return {"订单号": order_id, "状态": "制作中"}

from typing import List
from pydantic import BaseModel


class User(BaseModel):
    id: int
    name: str
    email: str


fake_db: List[User] = []


# 创建用户
@app.post("/users")
async def create_user(user: User):
    fake_db.append(user)
    return {"操作": "创建成功", "数据": user}


# 获取所有用户
@app.get("/users")
async def get_users():
    return fake_db


# 更新用户
@app.put("/users/{user_id}")
async def update_user(user_id: int, new_user: User):
    for index, user in enumerate(fake_db):
        if user.id == user_id:
            fake_db[index] = new_user
            return {"操作": "更新成功"}
    return {"错误": "用户不存在"}


# 删除用户
@app.delete("/users/{user_id}")
async def delete_user(user_id: int):
    global fake_db
    fake_db = [user for user in fake_db if user.id != user_id]
    return {"操作": "删除成功"}

# 路径参数
@app.get("/products/{category}")
async def get_by_category(category: str):
    ...


# 查询参数
@app.get("/search")
async def search_products(keyword: str, limit: int = 10):
    ...

from fastapi import Query


@app.get("/users")
async def filter_users(
        age: int = Query(..., ge=18, description="最小年龄"),
        is_vip: bool = Query(False)
):
    return [u for u in fake_db if u.age >= age and u.is_vip == is_vip]

# 危险代码
@app.get("/user/{name}")
async def get_user(name: str):
    query = f"SELECT * FROM users WHERE name = '{name}'"

# 你的任务：使用参数化查询改写

@app.get("/users")
async def get_users(
        page: int = Query(1, ge=1),
        size: int = Query(10, le=100)
):
    # 实现分页逻辑
    start = (page - 1) * size
    return fake_db[start:start + size]