python - 在 django rest 框架中按名称在通用关系中设置内容类型

Question

class Foo(models.Model):
    bar = models.CharField(max_length=300)
    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')


class FooSerializer(serializers.ModelSerializer):
    class Meta:
       model = Foo

class FooViewSet(viewsets.ModelViewSet):
    model = Foo
    serializer_class = FooSerializer

我现在可以将数据发布到如下所示的视图集：

{
    bar: 'content',
    content_type: 1
    object_id: 5
}

唯一困扰我的是前端必须知道内容类型 ID

相反，我希望能够将 content_types 名称（如“用户”）发布为 content_type，并让后端确定 id。

Answer 1

从 DRF 3.x 开始，用于读/写操作的最简单和最干净的方法：

from django.contrib.contenttypes.models import ContentType
from rest_framework import serializers
from .models import Foo

class FooSerializer(serializers.ModelSerializer):
    class Meta:
       model = Foo

    content_type = serializers.SlugRelatedField(
        queryset=ContentType.objects.all(),
        slug_field='model',
    )

然后，您可以使用模型名称执行 CRUD 操作：

data = {
    'bar': "content",
    'content_type': "model_name",
    'object_id': 1,
}

Answer 2

您可以自定义WritableField将内容类型 ID 映射到'app_label.model'字符串：

class ContentTypeField(serializers.WritableField):
    def field_from_native(self, data, files, field_name, into):
        into[field_name] = self.from_native(data[field_name])

    def from_native(self, data):
        app_label, model = data.split('.')
        return ContentType.objects.get(app_label=app_label, model=model)

    # If content_type is write_only, there is no need to have field_to_native here.
    def field_to_native(self, obj, field_name):
        if self.write_only:
            return None
        if obj is None:
            return self.empty
        ct = getattr(obj, field_name)
        return '.'.join(ct.natural_key())


class FooSerializer(serializers.ModelSerializer):
    content_type = ContentTypeField()
    # ...

您可能希望进行第二次映射以限制内容类型的选择并避免暴露您的应用程序/模型名称：

CONTENT_TYPES = {
  'exposed-contenttype': 'app_label.model'
}

class ContentTypeField(...):
    def from_native(self, data):
        if data not in CONTENT_TYPES:
            raise serializers.ValidationError(...)
        app_label, model = CONTENT_TYPES[data].split('.')
        # ...

Answer 3

DRF 已更改，现在代替 from_native 和 field_to_native 有新方法 - to_internal_value 和 to_representation。

现在更简单了：

class ContentTypeField(serializers.Field):

    def to_representation(self, obj):
        return obj.model

    def to_internal_value(self, data):
        return ContentType.objects.get(model=data)