后台任务

定义在返回响应后后台运行的任务，例如像发送邮件这种耗时动作

1. 在路径操作函数中导入BackgroundTasks并定义一个参数，其类型声明为：BackgroundTasks
2. 通过.add_task()添加任务

add_task()作为参数接收：

• 要在后台运行的任务函数 ( write_notification)。
• 后面参数为任务函数的所需参数

from fastapi import FastAPI, HTTPException, Request, BackgroundTasks, status
from fastapi.responses import JSONResponse
import uvicorn
import time
app = FastAPI()
def write_notification(email: str, message=""):
    with open('log.txt', "a") as email_file:
        time.sleep(3)
        content = f"输入的邮箱是: {email}, 发送的消息是: {message} \n"
        email_file.write(content)
@app.post("/send_nitification/{email}")
async def send_nitification(email: str, backgroud_task: BackgroundTasks):
    backgroud_task.add_task(write_notification, email, message="这是发送的消息")
    return JSONResponse(status_code=status.HTTP_200_OK,
                        content={
                            "code": 200,
                            "msg": "消息正在后台执行"
                        })
if __name__ == "__main__":
    uvicorn.run(
        app="error_handler:app",
        host="127.0.0.1",
        port=8080,
        reload=True,
        debug=True,
        log_level="debug",
        access_log=True,
        use_colors=True
    )