python - 使用 Django Rest Framework 序列化器创建外键关系的方法

Question

我的模型是这样的:

class FirewallPolicy(models.Model):
    name = models.CharField(max_length=100, unique=True)
    team = models.ForeignKey(Team)
    source_ip = models.ForeignKey(IP)
    destination_ip = models.ForeignKey(IP)

现在，为了创建新的防火墙策略，应该已经有一个现有团队、source_ip 和 destination_ip。我创建新防火墙策略的负载如下:

{"name": "test-create-policy-911",
 "team": "avengers",
 "source_ip": "1.1.1.1",
 "destination_ip": "2.2.2.2",
}

我创建新防火墙策略的序列化程序如下:

class FirewallPolicyCreateSerializer(serializers.ModelSerializer):
    name = serializers.CharField(max_length=100)
    team = serializers.CharField(max_length=100)
    source_ip = serializers.CharField(max_length=100)
    destination_ip = serializers.CharField(max_length=100)

    class Meta:
        model = Policy
        fields = ['id', 'name', 'team', 'source_ip', 'destination_ip']

    def validate(self, data):
        try:
            Team.objects.get(name=data['team'])
            IP.objects.get(name=data['source_ip'])
            IP.objects.get(name=data['destination_ip'])
        except ObjectDoesNotExist:
            raise serializers.ValidationError("Entities must exist before you can associate it with a Firewall Policy")

    def create(self, validated_data):
        team = Team.objects.get(name=validated_data['team'])
        source_ip = IP.objects.get(name=validated_data['source_ip'])
        destination_ip = IP.objects.get(name=validated_data['destination_ip'])
        policy  = Policy.objects.create(name=validated_data['name'], 
                                        team_id=team.id, 
                                        source_ip_id = source_ip.id, 
                                        destination_ip_id = destination_ip.id )
        return policy 

我不确定这是否是向模型添加外键的正确方法，因为它看起来工作量太大。在序列化程序可以自动检查所有这些并添加外键的地方，我是否遗漏了什么？

Answer 1

是的，你做的工作比你需要的多得多。

您应该使用 SlugRelatedField 定义您的字段允许 DRF 从相关模型上的字段自动填充它们。所以:

class FirewallPolicyCreateSerializer(serializers.ModelSerializer):
    team = serializers.SlugRelatedField(queryset=Team.objects.all(), slug_field='name')
    source_ip = serializers.SlugRelatedField(queryset=IP.objects.all(), slug_field='source_ip')
    destination_ip = serializers.SlugRelatedField(queryset=IP.objects.all(), slug_field='destination_ip')

    class Meta:
        model = Policy
        fields = ['id', 'name', 'team', 'source_ip', 'destination_ip']

现在你不需要定义 validate或 create根本没有，因为 DRF 将完成所有相关的验证和分配。

(注意，您也不需要重新定义 name 字段，因为您不会更改底层模型字段的任何内容。)