DRF ListAPIView return manytomany 值名称而不是 pk

Question

我有一个 Post 模型包含标签字段，该字段具有 ManyToManyField 类别模型，

当我调用 REST ListAPIView all post tags returns in pk 我试图覆盖 ListAPIView 中的列表函数并为每个 post 映射所有 tags_names 但这会花费大量时间并破坏性能

我 hope/Believe 为这种情况内置了一些东西

models.py

class Post(models.Model):
    author = models.ForeignKey(User, on_delete=models.CASCADE)
    title = models.CharField(max_length=256)
    content = RichTextField()
    tags = models.ManyToManyField(Categories)

    def __str__(self):
        return self.title



class Categories(models.Model):
    tag_name = models.CharField(max_length=256, unique=True)

    def __str__(self):
        return self.tag_name

    class Meta:
        ordering = ('tag_name',)
        unique_together = ('tag_name',)

views.py

from .models import Post
from .serializers import NewPostSerializer, PostSerializer


class NewPost(CreateAPIView):
    serializer_class = NewPostSerializer
    permission_classes = [IsAuthenticated, IsAdminUser]


class PostList(ListAPIView):
    queryset = Post.objects.all()
    serializer_class = PostSerializer

serializers.py

class NewPostSerializer(ModelSerializer):

    class Meta:
        model = Post
        fields = ['title', 'content', 'tags']

        read_only_fields = ['tags', 'author_id']

当我访问 ListApiView link 时返回的结果是这样的：

[
    {
        "id": 30,
        "title": "post title test",
        "content": "lorem text",
        "author": 3,
        "tags": [
            8, # should be games
            3  # should be action
        ]
    }
]

Answer 1

要优化性能，您应该使用 prefetch_related。这将对您的数据库的查询数量减少到只有 1 个请求来获取您所有帖子的所有相关标签。

class PostList(ListAPIView):
    queryset = Post.objects.prefetch_related('tags').all()
    serializer_class = NewPostSerializer

现在要对标签进行序列化，您必须创建一个新的序列化程序。

class TagSerializer(ModelSerializer):

    class Meta:
        model = Categories
        fields = ['name']

然后您可以在 NewPostSerializer.

中使用此序列化程序

class NewPostSerializer(ModelSerializer):
    tags = TagSerializer(many=True, read_only=True)

    class Meta:
        model = Post
        fields = ['title', 'content', 'tags']

        read_only_fields = ['author_id']

这个结果应该是"tags": [{"name": "ABC"},{"name": "EFG"}]。

Answer 2

您可以简单地使用 SlugRelatedField，这将 return 名称列表而不是 pks 列表

from rest_framework import serializers
class NewPostSerializer(ModelSerializer):

    tags = serializers.SlugRelatedField(
        many=True,
        read_only=True,
        slug_field='tag_name'
    )
    class Meta:
        model = Post
        fields = ['title', 'content', 'tags']

        read_only_fields = ['author_id']

DRF ListAPIView return manytomany 值名称而不是 pk

DRF ListAPIView return manytomany value names instead of pk

django

django-serializer

django-rest-framework