from datetime import datetime

from django.core.cache import cache

from django.db import models

from django.db.models.signals import post_delete, post_save

from django.utils import timezone

class Comment(models.Model):

name = models.CharField("名字", max_length=50)

email = models.EmailField("邮箱")

url = models.URLField("网址", blank=True)

text = models.TextField("内容")

created_time = models.DateTimeField("创建时间", default=timezone.now)

post = models.ForeignKey("blog.Post", verbose_name="文章", on_delete=models.CASCADE)

class Meta:

verbose_name = "评论"

verbose_name_plural = verbose_name

ordering = ["-created_time"]

def __str__(self):

return "{}: {}".format(self.name, self.text[:20])

def change_comment_updated_at(sender=None, instance=None, *args, **kwargs):

cache.set("comment_updated_at", datetime.utcnow())

post_save.connect(receiver=change_comment_updated_at, sender=Comment)

post_delete.connect(receiver=change_comment_updated_at, sender=Comment)