自定义钩子

class BaseSerializer(Field):
	@property
    def data(self):
        if not hasattr(self, '_data'):
            if self.instance is not None and not getattr(self, '_errors', None):
                self._data = self.to_representation(self.instance)
            elif hasattr(self, '_validated_data') and not getattr(self, '_errors', None):
                self._data = self.to_representation(self.validated_data)
            else:
                self._data = self.get_initial()
        return self._data

class Serializer(BaseSerializer, metaclass=SerializerMetaclass):
	@property
    def data(self):
        ret = super().data
        return ReturnDict(ret, serializer=self)
    def to_representation(self, instance):
        """
        Object instance -> Dict of primitive datatypes.
        """
        ret = OrderedDict()
		#内部会执行bind方法
        fields = self._readable_fields #找到所有的字段，然后筛选出可读的（可序列化的）。

        for field in fields:
		if hasattr(self, 'nb_%s' % field.field_name):
			value = getattr(self, 'nb_%s' % field.field_name)(instance)
			retret[field.field_name]=value
		else:
			attribute = field.get_attribute(instance)
			ret[field.field_name] = field.to_representation(attribute)
        return ret
class ModelSerializer(Serializer):
class NbModelSerializer(serializers.ModelSerializer):
    gender=serializers.SerializerMethodField()
    class Meta:
        model=models.Role
        fields=["id","name","age","gender"]
		extra_kwargs={
		"id"：{"read_inly":True}
		}
	def get_gender(self,obj):
		return obj.get_gender_dispalay()
		
ser = NbModelSerializer(instance=对象)
ser.data

ser= NbModelSerializer（data=request.data）
if ser.is_valid():
	ser.save()
	ser.data

#老师讲的码源也一脸蒙 所以先死记下来
#老师推荐的自定的方法
from collections import OrderedDict
from rest_framework.fields import SkipField
from rest_framework.relations import PKOnlyObject


class NbHookSerializer(object):

    def to_representation(self, instance):
        ret = OrderedDict()
        fields = self._readable_fields

        for field in fields:
            if hasattr(self, 'nb_%s' % field.field_name):
                value = getattr(self, 'nb_%s' % field.field_name)(instance)
                ret[field.field_name] = value
            else:
                try:
                    attribute = field.get_attribute(instance)
                except SkipField:
                    continue

                check_for_none = attribute.pk if isinstance(attribute, PKOnlyObject) else attribute
                if check_for_none is None:
                    ret[field.field_name] = None
                else:
                    ret[field.field_name] = field.to_representation(attribute)

        return ret