django序列化程序动态设置属性

是否可以动态设置

序列化程序的属性

CONTEXT_CLASSES = dict()
contexts = ['EmailContext', 'SmsMessageContext',...]

for ctx in contexts:
    Ctx_class = getattr(sys.modules[__name__], f'{ctx}Serializer')
    ctx_class_instance = Ctx_class(many=False, required=False, read_only=True)
    attr_name = ctx.split('Context')[0].lower() + '_ctx'
    CONTEXT_CLASSES[attr_name] = ctx_class_instance


class ContextContainerSerializer(serializers.ModelSerializer):

    for attr_name, instance in CONTEXT_CLASSES.items():
        # set attributes somehow

    class Meta:
         ...
         fields = tuple([value[0] for value in CONTEXT_CLASSES.values()])

将其放入
\uuuu init\uuuu
将不起作用，因为
类Meta
在它之前执行，并设置字段变量，该变量已包含属性名称，并将引发
django.core.exceptions.improverlyconfigured
 您可以在初始化时设置属性

class ContextContainerSerializer(serializers.ModelSerializer):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        # should be able to access "self.Meta"
        for attr_name, instance in CONTEXT_CLASSES.items():
            setattr(self.Meta, attr_name, instance)

或者要获得更动态的控制/模式，请使用
元类

from rest_framework.serializers import SerializerMetaclass


class ExtraContextMetaclass(SerializerMetaclass):
     def __new__(cls, name, bases, dct):
         """

         :param name:  name of class to be created
         :param bases: sub classes
         :param dct: other attributes
         :return:
         """

         new_class = super().__new__(cls, name, bases, dct)
         new_class.Meta = cls.dynamic_meta(new_class.Meta)
         return new_class

     @classmethod
     def dynamic_meta(cls, old_meta):
         # create a class called "Meta"
         new_meta = type('Meta', (), dict(fields=None))

         # copy over required attributes from original Meta
         new_meta.model = old_meta.model
         new_meta.fields = list(old_meta.fields[:])

         # set new attributes dynamically 
         for attr_name, instance in CONTEXT_CLASSES.items():
             setattr(new_meta, attr_name, instance)

         return new_meta


class ContextContainerSerializer(serializers.ModelSerializer, 
                                 metaclass=ExtraContextMetaclass):

    class Meta:
        model = Model
        fields = ['some_field']

您可以尝试ContextContainerSerializer（context=context\u类）。并通过self.context.get（attr_name）在类序列化中获取第一个将不起作用，因为我正在定义
类元
中的字段，该字段在
\uuuu init\uu
之前执行，第二个版本似乎也会引起问题，因为
\uu new\u
在
类元
之前执行（很抱歉之前没有添加元-我现在更新了代码）我已经更新了答案以反映更新后的问题