Django:模型上缺少信号回调函数
哎,, 我正试着让信号pre_save在我的模型上工作,但是没有 外键好像有问题。我的模型是 像这样:Django:模型上缺少信号回调函数,django,callback,django-signals,Django,Callback,Django Signals,哎,, 我正试着让信号pre_save在我的模型上工作,但是没有 外键好像有问题。我的模型是 像这样: class BlogEntry(models.Model): headline = models.CharField(max_length=100) content = models.CharField(max_length=2000) written_by = models.ForeignKey(User) date = models.DateTimeFiel
class BlogEntry(models.Model):
headline = models.CharField(max_length=100)
content = models.CharField(max_length=2000)
written_by = models.ForeignKey(User)
date = models.DateTimeField(auto_now=True)
project = models.ForeignKey(Project)
@receiver(post_save, sender=BlogEntry)
def project_blog_entry_signal(sender, **kwargs):
log = Log()
log.project = kwargs["instance"].project
log.content_type = Log.content_new_blogentry
log.save()
这里是处理和保存表单的位置:
def form_valid(self, blogform): # post a blogentry
blog_entry = blogform.save(commit=False)
blog_entry.written_by = self.request.user
blog_entry.project = blog_entry.project #debugging shows that this
is a valid instance of the Project model
blog_entry.save()
return TemplateResponseMixin.render_to_response(self,
self.get_context_data())
这是我的信号接收器功能
@receiver(post_save, sender=BlogEntry)
def project_blog_entry_signal(sender, **kwargs):
log = Log()
log.project = sender.project.field
log.content_type = Log.content_new_blogentry
log.save()
这里有一个例外:
无法分配
“django.db.models.fields.related.ForeignKey
0x21eef86c处的对象“:“Log.project”
必须是“项目”实例
@行-->log.project=
中的sender.project.field
project\u blog\u entry\u signal()函数
发送方对象似乎不是作为模型实例传递项目,而是作为外键实例传递。为什么呢 解决了它。“sender”参数只是一个类对象,而不是实例。在我的回调中,我可以通过kwargs引用实例,如: blog\u entry\u instance=kwargs[“instance”] 因此回调函数如下所示:
class BlogEntry(models.Model):
headline = models.CharField(max_length=100)
content = models.CharField(max_length=2000)
written_by = models.ForeignKey(User)
date = models.DateTimeField(auto_now=True)
project = models.ForeignKey(Project)
@receiver(post_save, sender=BlogEntry)
def project_blog_entry_signal(sender, **kwargs):
log = Log()
log.project = kwargs["instance"].project
log.content_type = Log.content_new_blogentry
log.save()
为了节省一些输入,您可以将函数参数定义为“def project\u blog\u entry\u signal(sender,instance,**kwargs)”。这样,您就不需要键入“kwargs[“instance”]”,而是键入“instance:)