FastAPI系列：后台任务进程

注：后台任务应附加到响应中，并且仅在发送响应后运行

用于将单个后台任务添加到响应中

from fastapi import FastAPI
from fastapi.responses import JSONResponse
from starlette.background import BackgroundTask
from pydantic import  BaseModel

app = FastAPI()

class User(BaseModel):
    username: str
    email: str


@app.get('/signup')
async def signup(data: User):
    username = data.username
    email = data.email
    task = BackgroundTask(send_welcome_emil, username=username, to_address=email)
    message = {'status': 'Signup successful'}
    return JSONResponse(message, background=task)

async def send_welcome_emil(username, to_address):
    print("模拟发送邮件：：：：")
    print('用户：', username)
    print('地址：', to_address)
    # 模拟发送邮件
    import asyncio 
    await asyncio.sleep(5)

if __name__ == '__main__':
    import uvicorn
    uvicorn.run('background:app', host='0.0.0.0', port=8888, reload=True)

通过BackgroundTasks的add_task添加后台任务

from fastapi  import BackgroundTasks, FastAPI

# backgrounds.py
from datetime import datetime

# 记录用户行为
def audit_log_transaction(userID: str, message=""):
    with open("user_log.txt", mode="a") as f:
        content = f"user {userID} message {message} at {datetime.now()}"
        f.write(content)
        
#user.py
@router.post("/bgtask")
def login(user: User, bg_task:BackgroundTasks): # 通过注入的形式就可以使用
    if user:
        # 添加任务add_task
        bg_task.add_task(audit_log_transaction, userID=user.id, message="login")
    return jsonable_encoder(user)