Django Generic Relations错误：“无法将关键字”content_object'解析为字段“ [英] Django Generic Relations error: "cannot resolve keyword 'content_object' into field"

问题描述

我正在使用Django的通用关系来定义问答模型的投票模型。

这是我的投票模式：

models.py

  class Vote（models.Model）：
 user_voted = models.ForeignKey（MyUser）
 is_upvote = models.BooleanField（default = True）
 
＃通用外键
 content_type = models.ForeignKey（ContentType）
 object_id = models.PositiveIntegerField（）
 content_object = generic.GenericForeignKey（'content_type'，'object_id'）
 
 class Meta：
 unique_together =（'content_type'，'user_voted'）
  

views.py

  user_voted = MyUser.objects.get（id = request.user.id）
 object_type = request.POST.get（'object_type'）
 
 object = None; 
如果object_type =='question'：
 object = get_object_or_404（Question，id = self.kwargs ['pk']）
 elif object_type =='answer'：
 object = get_object_or_404（Answer，id = self.kwargs ['pk']）
 
＃这是最近的线给我的错误
 vote，created = Vote.objects.get_or_create（user_voted = user_voted， content_object = object）
  

然后我得到这个错误：

  / 1 / 
中的FieldError无法将关键字content_object解析为字段。选择是：answer，content_type，id，is_upvote，object_id，question，user_voted 
  

>
当我将对象打印到Django控制台时，它会打印Question 1对象。所以我不明白为什么这行content_object = object给我的字段错误...

任何想法：（（（???

谢谢

解决方案

content_object 是一种只读属性，它将检索由 content_type 和 object_id 的字段指定的对象，您应该替换你的代码如下：

  from django.contrib.contenttypes.models import ContentType 
 type = ContentType.objects。 get_for_model（object）
 vote，created = Vote.objects.get_or_create（user_voted = user_voted，content_type = type，object_id = object.id）
  

编辑： Django 文档明确说明：

由于GenericForeignKey的实现方式，您不能使用suc通过数据库API直接使用过滤器（filter（）和exclude（））。因为GenericForeignKey不是正常的字段对象，这些示例将无法正常工作：

 这将失败
>>> TaggedItem.objects.filter（content_object = guido）
＃这也将失败
>>> TaggedItem.objects.get（content_object = guido）
  

I'm using Django's Generic Relations to define Vote model for Question and Answer models.

Here is my vote model:

models.py

class Vote(models.Model):
    user_voted = models.ForeignKey(MyUser)
    is_upvote = models.BooleanField(default=True)

    # Generic foreign key
    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = generic.GenericForeignKey('content_type', 'object_id')

    class Meta:
        unique_together = ('content_type', 'user_voted')

views.py

        user_voted = MyUser.objects.get(id=request.user.id)
        object_type = request.POST.get('object_type')

        object = None;
        if object_type == 'question':
            object = get_object_or_404(Question, id=self.kwargs['pk'])
        elif object_type == 'answer':
            object = get_object_or_404(Answer, id=self.kwargs['pk'])

        # THIS LAST LINE GIVES ME THE ERROR
        vote, created = Vote.objects.get_or_create(user_voted=user_voted, content_object=object)

And then I get this error:

FieldError at /1/ 
Cannot resolve keyword 'content_object' into field. Choices are: answer, content_type, id, is_upvote, object_id, question, user_voted

When I print the "object" to Django console, it prints "Question 1" object. So I don't understand why the line "content_object=object" gives me the field error...

Any ideas :(((???

Thanks

解决方案

content_object is a sort of read-only attribute that will retrieve the object specified by fields content_type and object_id. You should replace your code by the following:

from django.contrib.contenttypes.models import ContentType
type = ContentType.objects.get_for_model(object)
vote, created = Vote.objects.get_or_create(user_voted=user_voted, content_type=type, object_id=object.id)

Edit: Django documentation explicitly remarks:

Due to the way GenericForeignKey is implemented, you cannot use such fields directly with filters (filter() and exclude(), for example) via the database API. Because a GenericForeignKey isn’t a normal field object, these examples will not work:

# This will fail
>>> TaggedItem.objects.filter(content_object=guido)
# This will also fail
>>> TaggedItem.objects.get(content_object=guido)

这篇关于Django Generic Relations错误：“无法将关键字”content_object'解析为字段“的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！