问题描述
我正在尝试创建一个通知系统来跟踪我的用户的所有活动。为了实现这一点,我创建了两个模型,贡献模型和通知模型
class Contribution(models.Model):
slug = models.SlugField(unique=True,blank=True,null=True)
user = models.ForeignKey(User,on_delete=models.PROTECT)
amount = models.DecimalField(default=0.00,max_digits=6,decimal_places=2)
zanaco_id = models.CharField(max_length=20,unique=True,null=True)
class Notification(models.Model):
slug = models.SlugField(unique=True,blank=True)
content_type = models.ForeignKey(ContentType,on_delete=models.CASCADE)
object_id = models.PositiveIntegerField()
content_object = GenericForeignKey('content_type','object_id')
message = models.TextField(null=True)
每次用户在 Contribution 表中创建对象时,我都想创建一个 Notification 对象,但在从 CreateView 创建对象时遇到一些困难
class ContributionAdd(CreateView):
model = Contribution
fields = ['user','amount','zanaco_id']
template_name = 'contribution_add.html'
def form_valid(self,form,*args,**kwargs):
activity_ct = ContentType.objects.get_for_model("????")
Notification.objects.create(content_type=activity_ct,object_id="?????",content_object=???,)
return super().form_valid(form)
我怎样才能完成上面的任务? 他们是使用 mixins 来做到这一点的方法吗?
解决方法
该对象是在超级 form_valid
方法中创建的,因此在调用之前您无法访问它。而是先调用 super 方法并使用 self.object
来引用创建的对象:
class ContributionAdd(CreateView):
model = Contribution
fields = ['user','amount','zanaco_id']
template_name = 'contribution_add.html'
def form_valid(self,form):
response = super().form_valid(form) # call super first
Notification.objects.create(content_object=self.object) # Why even pass the other values just pass `content_object` only
return response
,
一种优雅的方法是使用保存后信号:
from django.dispatch import receiver
from django.db.models.signals import post_save
@receiver(post_save,sender=Contribution)
def createNotification(sender,instance,created,**kwargs):
if created:
Notification.objects.create(content_type=activity_ct,object_id="?????",content_object=???,)