Django 序列化程序中的反向外键

Question

假设

class Post(models.Model):
    content = ...
    image = ...
    timestamp = ...

class PostLike(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL,...)
    post = models.ForiegnKey(Post,...)
    timestamp = ...

和

class PostSerializer(serializers.ModelSerializer):
    class Meta:
        model = Post
        fields = ("content","image","timestamp","liked")

这里喜欢可以是真也可以是假。如果用户 (request.user) 在 PostLike 中，则为真。

如何创建喜欢的字段？

查看

@login_required()
def AllPosts(request):
    obj = Posts.objects.all()
    serializer = PostSerializer(obj, many=True)
    result = JsonResponse(serializer.data, safe=False)
    return result

Answer 1

您的序列化程序已经有一个 liked 属性的字段，唯一缺少的是一个字段：

class PostSerializer(serializers.ModelSerializer):
    liked = <strong>serializers.BooleanField(read_only=True)</strong>
    class Meta:
        model = Post
        fields = ('content', 'image', 'timestamp', 'liked')

您需要的是 QuerySet，其中的帖子具有额外的属性 .liked 您可以使用额外的属性来注释 Post 对象，该属性指定对象是否被点赞：

from django.db.models import Exists, OuterRef

def @login_required
def AllPosts(request):
    obj = Posts.objects.get_queryset(*args, **kwargs).annotate(
        liked=Exists(
            <strong>PostLike.objects.filter(user=request.user, post_id=OuterRef('pk')</strong>)
        )
    )
    serializer = PostSerializer(obj, many=True)
    result = JsonResponse(serializer.data, safe=False)
    return result

Django 序列化程序中的反向外键

Reverse Foriegn Key in Django Serializers

django

serialization

django-models

django-serializer

django-rest-framework