你能制作一个在 Django 中删除自身的对象吗？

Question

所以我制作了模型VerificationToken

class VerificationToken(models.Model):

    user = models.ForeignKey(User, on_delete=models.CASCADE)
    code = models.CharField(max_length=4)
    date_created = models.DateTimeField(auto_now_add=True)


    @property
    def expiration(self):

        lifetime = timedelta(minutes=10)

        expire = self.date_created + lifetime

        return expire

并且此模型有有效期属性。有没有办法让这个模型过期后自行删除？

Answer 1

我相信 Django 不提供那种功能。您可以使用 Celery 创建一个 celery 任务，该任务将删除在一定时间后过期的令牌。您还可以创建定期查找过期令牌并将其删除的任务。

Celery documentation

Answer 2

很遗憾，这是不可能的。您可以做的是使用 celery-beat 或您喜欢的方式创建一个 cronjob，并设置一个 cronjob 任务来清理过期的数据库记录（每个 minute/hour/day 一次）

Answer 3

只需制作一个过滤器以防止检索过期的 VerificationTokens:

from datetime import timedelta
from django.db.models.functions import Now

VerificationToken.objects.filter(
    <strong>date_created__gte=Now()-timedelta(minutes=10)</strong>
)

您也可以创建一个管理器，使得 VerificationToken.objects 是一个仅包含 non-expired 个令牌的管理器：

from datetime import timedelta
from django.conf import settings
from django.db.models.functions import Now

class <strong>VerificationTokenManager</strong>(models.Manager):
    
    def get_queryset(self):
        return super().get_querset().filter(
            date_created__gte=Now()-timedelta(minutes=10)
        )

class VerificationToken(models.Model):
    user = models.ForeignKey(
        <strong>settings.AUTH_USER_MODEL</strong>,
        on_delete=models.CASCADE
    )
    code = models.CharField(max_length=4)
    date_created = models.DateTimeField(auto_now_add=True<strong>, db_index=True</strong>)
    objects = <strong>VerificationTokenManager()</strong>

然后您可以创建一个 management command [Django-doc]，例如运行通过 cron，或其他一些删除过期 VerificationToken 的调度任务：

# app_name/management/commands/remove_expired_tokens.py

from datetime import timedelta
from django.core.management.base import BaseCommand
from django.db.models.functions import Now
from <em>app_name</em>.models import VerificationToken

class Command(BaseCommand):
    help = 'Remove expired verification tokens'

    def handle(self, *args, **options):
        VerificationToken._base_manager.filter(
            <strong>date_created__lt=Now()-timedelta(minutes=10)</strong>
        )<strong>.delete()</strong>

Note: It is normally better to make use of the settings.AUTH_USER_MODEL [Django-doc] to refer to the user model, than to use the User model [Django-doc] directly. For more information you can see the referencing the User model section of the documentation.

你能制作一个在 Django 中删除自身的对象吗？

Can you make an objects that deletes itself in Django?

python

django

django-models