Django-Rest 框架中的反向关系答案

【问题标题】：Reverse Relationships in Django-Rest frameworkDjango-Rest 框架中的反向关系
【发布时间】：2016-09-12 09:03:43
【问题描述】：

我有两个模型。现在 Class Track Model 有一个 Album 外键。我想写一个具有专辑名称的音轨序列化器。我怎样才能做到这一点？

class Album(models.Model):
    album_name = models.CharField(max_length=100)
    artist = models.CharField(max_length=100)

class Track(models.Model):
    album = models.ForeignKey(Album, related_name='tracks')
    order = models.IntegerField()
    title = models.CharField(max_length=100)
    duration = models.IntegerField()

    class Meta:
        unique_together = ('album', 'order')
        ordering = ['order']

    def __unicode__(self):
        return '%d: %s' % (self.order, self.title)

我将 Track 的 depth 参数设置为 1，但这会检索专辑名称以及艺术家。我只想要 Track Serializer 中的专辑名称

【问题讨论】：

标签： django django-rest-framework

【解决方案1】：

有很多解决方案。您可以使用多种类型的字段 e。 G。 StringRelatedField 或 SerializerMethodField。

这是一个带有自定义相关字段的示例：

from rest_framework import serializers


class TrackField(serializers.RelatedField):

    def to_representation(self, value):
        return value.album_name


class TrackSerializer(serializers.ModelSerializer):

    album = TrackField(queryset=Album.objects.all())

    class Meta:
        model = Track
        fields = ('album', 'order', 'title', 'duration')

这会产生：

track = Track.objects.get(...)

TrackSerializer(track).data  # Returns {'album': <name of the album>, ...}

【讨论】：

【解决方案2】：

class BaseSerializer(serializers.ModelSerializer):
    """
    A Base Serializer that takes an additional `fields` argument that
    controls which fields should be displayed.
    """

    def __init__(self, *args, **kwargs):
        # Don't pass the 'fields' arg up to the superclass
        fields = kwargs.pop('fields', None)
        exclude = kwargs.pop('exclude', None)
        # Instantiate the superclass normally
        super(BaseSerializer, self).__init__(*args, **kwargs)

        if fields:
            # Drop any fields that are not specified in the `fields` argument.
            allowed = set(fields)
            existing = set(self.fields.keys())
            for field_name in existing - allowed:
                self.fields.pop(field_name)
        if exclude:
            # Drop fields that are specified in the `exclude` argument.
            excluded = set(exclude)
            for field_name in excluded:
                try:
                    self.fields.pop(field_name)
                except KeyError:
                    pass

我使用上面的类来明确排除我不想要的参数，

信用：How to exclude parent when serializer is nested when using Django REST Framework?

【讨论】：