Django Rest Framework – Custom Hyperlink field in serializer

Question

How can I add a custom hyperlink field in a serializer? I would like to have a hyperlink field in my serializer that has query params in it. Since there is no way to pass query params from HyperlinkedRelatedField or HyperlinkedIdentityField as far as I know, I've tried using a SerializerMethodField. However, this only serializes to a string, and is not a clickable URL when I visit the API through my browser. My code looks something like this:

class MySerializer(serializers.HyperlinkedModelSerializer):
    custom_field = serializers.SerializerMethodField()

    class Meta:
        model = MyModel
        fields = ('url', 'custom_field')

    def get_custom_field(self, obj):
        result = '{}?{}'.format(
            reverse('my-view'),
            urllib.urlencode({'param': 'foo'})
        )
        return result

Also, I am having trouble understanding the difference between a HyperlinkedRelatedField and a HyperlinkedIdentityField, so a brief explanation would be appreciated.

Answer 1

这应该可以解决问题：

from rest_framework.reverse import reverse

class MySerializer(serializers.HyperlinkedModelSerializer):
    custom_field = serializers.SerializerMethodField()

    class Meta:
        model = MyModel
        fields = ('url', 'custom_field')

    def get_custom_field(self, obj):
        result = '{}?{}'.format(
            reverse('my-view', args=[obj.id], request=self.context['request']),
            'param=foo'
        )
        return result

rest_framework中的反向函数采用一个视图名称（无论您要链接到哪个视图），一个args列表（在这种情况下为对象ID）或kwargs，以及一个请求对象（可以在序列化器内部访问）self.context['request']）。此外，它还可以使用要传递给它的format参数和任何其他参数（作为字典）。

然后，反向功能将为您构建一个漂亮的，格式完整的URL。您可以向其中添加查询参数，只需?{}&{}&{}在结果变量中添加尽可能多的参数，然后在format函数中“ param = foo”下方的一系列查询参数中添加所需的其他参数即可。

的HyperlinkedIdentityField使用正被序列化的对象本身。因此HyperlinkedIdentifyField，正在使用a 代替您的主键字段，MyModel因为您正在使用a HyperlinkedModelSerializer，它HyperlinkedIdentityField为要序列化的对象本身的pk 创建一个a 。

该HyperlinkedRelatedField用来定义相关对象超链接关系。因此，如果存在MySecondModel与外键的关系，MyModel并且您希望在MyModel序列化程序上具有指向所有相关MySecondModel对象的超链接，则应使用HyperlinkedRelatedField这样的方式（请记住将新字段添加到Meta中的fields属性中）：

class MySerializer(serializers.HyperlinkedModelSerializer):
    custom_field = serializers.SerializerMethodField()
    mysecondmodels = serializers.HyperlinkedRelatedField(
        many=True
        read_only=True,
        view_name='mysecondmodel-detail'
    )

    class Meta:
        model = MyModel
        fields = ('url', 'custom_field', 'mysecondmodels')

    def get_custom_field(self, obj):
        result = '{}?{}'.format(
            reverse('my-view', args=[obj.id], request=self.context['request']),
            'param=foo'
        )
        return result

如果它是一个OneToOneField而不是ForeignKey字段，MySecondModel那么您将设置many = False。

希望这可以帮助！