FastAPI怎样通过中间件捕获所有未处理异常并格式化输出？

from fastapi import FastAPI, Request, HTTPException
from fastapi.responses import JSONResponse
import logging

app = FastAPI()

# 配置日志
logging.basicConfig(level=logging.ERROR)
logger = logging.getLogger(__name__)

async def catch_exceptions_middleware(request: Request, call_next):
    try:
        return await call_next(request)
    except HTTPException as e:
        return JSONResponse({"error": e.detail}, status_code=e.status_code)
    except Exception as e:
        logger.exception(f"Unhandled exception: {e}") # 记录完整的异常信息
        return JSONResponse({"error": "Internal Server Error"}, status_code=500)

app.middleware("http")(catch_exceptions_middleware)

@app.get("/items/{item_id}")
async def read_item(item_id: int):
    if item_id == 0:
        raise HTTPException(status_code=400, detail="Item ID cannot be zero")
    # 模拟一个其他类型的异常
    if item_id == 1:
        raise ValueError("Invalid item ID")
    return {"item_id": item_id}

from datetime import datetime

async def catch_exceptions_middleware(request: Request, call_next):
    try:
        return await call_next(request)
    except HTTPException as e:
        return JSONResponse({
            "timestamp": datetime.utcnow().isoformat(),
            "path": request.url.path,
            "error": e.detail
        }, status_code=e.status_code)
    except Exception as e:
        logger.exception(f"Unhandled exception: {e}")
        return JSONResponse({
            "timestamp": datetime.utcnow().isoformat(),
            "path": request.url.path,
            "error": "Internal Server Error"
        }, status_code=500)

import asyncio
from fastapi import BackgroundTasks

async def my_task(item_id: int):
    try:
        # 模拟一个可能抛出异常的任务
        await asyncio.sleep(1)
        if item_id == 2:
            raise ValueError("Task failed")
        print(f"Task completed for item {item_id}")
    except Exception as e:
        logger.exception(f"Task failed: {e}")

@app.post("/tasks")
async def create_task(item_id: int, background_tasks: BackgroundTasks):
    background_tasks.add_task(my_task, item_id)
    return {"message": "Task started"}

from fastapi.testclient import TestClient

client = TestClient(app)

def test_read_item_invalid_id():
    response = client.get("/items/0")
    assert response.status_code == 400
    assert response.json() == {"error": "Item ID cannot be zero"}

def test_read_item_value_error():
    response = client.get("/items/1")
    assert response.status_code == 500
    assert "error" in response.json() # 仅仅检查error键是否存在，不检查具体内容