我试图让这个在“NUM_POSTS”博客中对象的字段递减一次属于该博客的一篇文章被删除的时间,增加每次一个贴子创建。我能实现重载的保存方法很轻松地:Django的post_delete()信号处理程序不工作
def save(self, *args, **kwargs):
'''After saving a new post, increment the num_posts value in the
relevant blog.'''
super(Posts, self).save(*args, **kwargs)
self.blog_id.num_posts += 1
tmp = self.blog_id
tmp.save()
但无论出于何种原因,删除帖子对象时的逻辑行不通。我通过在handlers.py
文件中信号的子模块使用信号处理程序遵循最佳实践。然后我导入子模块在我ready()
方法在我TasksConfig(Appconfig)
方法apps.py
我似乎并没有得到任何语法错误,或者在所有的任何错误。就有关博客的num_posts
场只是失败递减。下面是相关代码:
从我handlers.py
:
from django.db.models.signals import pre_delete
from django.dispatch import receiver
from webcomics.models import Pages, Posts, Blogs
@receiver(pre_delete, sender=Pages)
def handle_page_delete(sender, **kwargs):
obj = kwargs['instance']
if(obj != None):
tmp1 = obj.prev_id
tmp2 = obj.next_id
if(tmp1 != None):
tmp1.next_id = tmp2
obj.prev_id = None
if(tmp2 != None):
tmp2.prev_id = tmp1
obj.next_id = None
@receiver(pre_delete, sender=Posts)
def handle_bpost_delete(sender, **kwargs):
obj = kwargs['instance']
if(obj != None):
tmp = Blogs.objects.get(pk = obj.blog_id)
tmp.num_pages = tmp.num_pages - 1
从我apps.py
:
from django.apps import AppConfig
class WebcomicsConfig(AppConfig):
name = 'webcomics'
class TasksConfig(AppConfig):
name = 'tasks'
verbose_name = "Tasks"
def ready(self):
import binshellpress.webcomics.signals.handlers
而且,这里是完整的帖子对象models.py
,以防万一你们可以看到我失踪的东西:
class Posts(models.Model):
title = models.CharField(max_length=180)
pub_date = models.DateTimeField('date publishied', default=timezone.now)
blog_id = models.ForeignKey('Blogs', on_delete=models.CASCADE)
series_id = models.ForeignKey('Series', on_delete=models.SET_NULL,
blank=True, null=True)
# Note: Vanilla TinyMCE Integration seems to be working. Need to
# modify the implementation to handle links, images, etc.
data = HTMLField()
def __str__(self):
return self.title
def save(self, *args, **kwargs):
'''After saving a new post, increment the num_posts value in the
relevant blog.'''
super(Posts, self).save(*args, **kwargs)
self.blog_id.num_posts += 1
tmp = self.blog_id
tmp.save()
我怀疑这是明显的。我只是无所适从,因为似乎没有任何错误消息来自任何地方。
你们为什么试探,如果'kwargs [ “实例”] == None'? 'pre_delete'信号总是通过一个实例,还是有一些严重的错误。 和'Blogs.num_posts'可以简单地定义为返回'self.pages_set.count一个属性()'。这将比手动添加和减少更容易出错。 –