Django Rest-Framework嵌套序列化器命令

Question

有没有办法订购嵌套的序列化程序_set,例如order by pk或time-stamp.

所以基本上song_set在下面的json数据中显示的顺序是从最相邻的最新对象创建的,在本例中是order_by('-timestamp')或order_by('-pk').

Json数据

{
    "pk": 151,
    "album_name": "Name",
    "song_set": [
         {
           pk: 3,
           timestamp: '5 seconds'
         },
         {
           pk: 2,
           timestamp: '10 seconds'
         },
         {
           pk: 1,
           timestamp: '15 seconds'
         }
    ]
}

模型

class Album(models.Model):
    album_name     = models.CharField(max_length=100, blank=True)


class Song(models.Model):
    album          = models.ForeignKey('album.Album', default=1)
    timestamp      = models.DateTimeField(auto_now_add=True, auto_now=False)

Searilizer

class SongListSerializer(HyperlinkedModelSerializer):
    class Meta:
        model = Song
        fields = [
            'pk',
            'timestamp'
        ]

class AlbumSerializer(HyperlinkedModelSerializer):
    song_set = SongListSerializer(many=True, read_only=True)
    class Meta:
        model = Album
        fields = [
            'pk',
            'timestamp',
            'song_set'
        ]

Answer 1

将排序元参数添加到您的 Song 模型中：

class Song(models.Model):
    album = models.ForeignKey('album.Album', default=1)
    timestamp = models.DateTimeField(auto_now_add=True, auto_now=False)

    class Meta:
        ordering = ['timestamp', 'pk']

Answer 2

您可以SerializerMethodField为此使用和编写自定义方法.

class AlbumSerializer(HyperlinkedModelSerializer):
    song_set = serializers.SerializerMethodField()
    class Meta:
        model = Album
        fields = [
            'pk',
            'timestamp',
            'song_set'
        ]

    def get_song_set(self, instance):
        songs = instance.song_set.all().order_by('-timestamp')
        return SongListSerializer(songs, many=True).data

Answer 3

在您的 中ViewSet，您可以指定一个带有自定义Prefetch对象的查询集，您可以根据需要对其进行过滤和排序。预取仅导致一个额外的数据库查询（而不是使用 时每个父对象一个SerializerMethodField），从而大大提高了性能。

from rest_framework import viewsets
from django.db.models import Prefetch

class AlbumViewSet(viewsets.ModelViewSet):
    queryset = Album.objects.prefetch_related(Prefetch('song_set',
        queryset=Song.objects.order_by('-timestamp')))

Answer 4

旧线程，但因为它仍然出现在谷歌上，我也想分享我的答案。尝试覆盖该Serializer.to_representation方法。现在您基本上可以做任何您想做的事情，包括自定义响应的排序。在你的情况下：

class AlbumSerializer(HyperlinkedModelSerializer):
    song_set = SongListSerializer(many=True, read_only=True)
    class Meta:
        model = Album
        fields = [
            'pk',
            'timestamp',
            'song_set'
        ]

    def to_representation(self, instance):
        response = super().to_representation(instance)
        response["song_set"] = sorted(response["song_set"], key=lambda x: x["timestamp"])
        return response