我有以下简单的models.py
文件:
from django.db import models
from model_utils.managers import InheritanceManager
class Clique(models.Model):
created = models.DateTimeField(auto_now_add=True)
name = models.CharField(max_length=100, blank=False)
class Post(models.Model):
created = models.DateTimeField(auto_now_add=True)
headline = models.TextField()
clique = models.ForeignKey(Clique,
on_delete=models.CASCADE,
blank=True,
null=True)
objects = InheritanceManager()
def __str__(self):
return self.headline
class VideoPost(Post):
video = models.BooleanField(default=True)
class ImagePost(Post):
image = models.BooleanField(default=True)
因此,有一个Clique
模型可以包含多个Post
实例。Post
实例可以是ImagePost
或VideoPost
。因此,ImagePost
和VideoPost
都继承Post
。你知道吗
现在,假设我要检索ImagePost子类实例。因此,我的观点如下视图.py文件:
class PostList(generics.ListAPIView):
serializer_class = PostSerializer
def get_queryset(self):
return Post.objects.select_subclasses(ImagePost)
当我在url中传递端点posts/
时,就会触发这个视图,它应该只给我ImagePost
实例,对吗?但我也从数据库中获取VideoPost
实例:
[
{
"clique": "http://127.0.0.1:8000/cliques/1/",
"comment_set": [],
"created": "2019-06-18T09:52:47.929623Z",
"headline": "FirstImagePost",
"id": 1,
"url": "http://127.0.0.1:8000/posts/1/"
},
{
"clique": "http://127.0.0.1:8000/cliques/1/",
"comment_set": [],
"created": "2019-06-18T09:53:20.266653Z",
"headline": "FirstVideoPost",
"id": 2,
"url": "http://127.0.0.1:8000/posts/2/"
}
]
为什么会这样?我浏览了官方文件。有人能帮忙吗
为了完整起见,我的serializers.py
文件如下所示:
from rest_framework import serializers
from posts.models import Post, VideoPost, ImagePost, Clique
class CliqueSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Clique
fields = ('id', 'name', 'post_set')
read_only_fields = ('post_set', )
class PostSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Post
fields = ('url', 'id', 'created', 'headline', 'clique', 'comment_set',)
read_only_fields = ('comment_set',)
class VideoPostSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = VideoPost
fields = '__all__'
class ImagePostSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = ImagePost
fields = '__all__'
从文档中看,
select_subclasses
似乎没有按子类类型进行筛选,它只在与您提供的匹配时将其转换为子类。你知道吗对你来说
将所有ImagePost转换为ImagePost实例,将其他的作为Post对象,它不会过滤掉它。你知道吗
从这里的文件:
在您的情况下,您可以简单地执行以下操作:
尽管我认为你不需要
select_subclasses(ImagePost)
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