Django Rest-Framework嵌套序列化程序顺序 [英] Django Rest-Framework nested serializer order

问题描述

是否可以订购嵌套序列化器 set ，例如按 pk 或<$ c $进行订购c>时间戳。

Is there a way to order a nested serializer _set, for example order by pk or time-stamp.

因此基本上订购json数据中显示的 song_set 从最近创建的对象到最新创建的对象，在这种情况下，由 order_by（'-timestamp'）或 order_by（'-pk'）。

So basically order song_set shown in the json data below from the most recent to the latest object created, in this case by order_by('-timestamp') or 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)

序列化器

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'
        ]

推荐答案

您可以使用 SerializerMethodField 并为此编写自定义方法。

You can use SerializerMethodField and write custom method for this.

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

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