cached_property 和 classmethod 不能一起工作，Django

Question

我试图在视图集中一起使用cached_property和classmethod装饰器，但无论它们的相互位置如何，它都不起作用。有没有机会让它一起工作或cached_property不工作classmethod？特南克斯。

    @cached_property
    @classmethod
    def get_child_extra_actions(cls):
        """
        Returns only extra actions defined in this exact viewset exclude actions defined in superclasses.
        """
        all_extra_actions = cls.get_extra_actions()
        parent_extra_actions = cls.__base__.get_extra_actions()
        child_extra_actions = set(all_extra_actions).difference(parent_extra_actions)
        return (act.__name__ for act in child_extra_actions)

Answer 1

对于具有类方法用法的缓存属性，我几天前编写了该代码：

from django.utils.decorators import classproperty

class cached_classproperty(classproperty):
    def get_result_field_name(self):
        return self.fget.__name__ + "_property_result" if self.fget else None

    def __get__(self, instance, cls=None):
        result_field_name = self.get_result_field_name()

        if hasattr(cls, result_field_name):
            return getattr(cls, result_field_name)

        if not cls or not result_field_name:
            return self.fget(cls)

        setattr(cls, result_field_name, self.fget(cls))
        return getattr(cls, result_field_name)

它将在类级别缓存结果。
用法类似于classproperty：

@cached_classproperty
def some_func(cls, *args, **kwargs):
    ...

如果您的依赖项中没有 django，那么您可能希望阻止classproperty父级使用（sources）。在这种情况下，您可以使用该装饰器：

class cached_classproperty(classproperty):
    def __init__(self, method=None):
        self.fget = method

    def get_result_field_name(self):
        return self.fget.__name__ + "_property_result" if self.fget else None

    def __get__(self, instance, cls=None):
        result_field_name = self.get_result_field_name()

        if hasattr(cls, result_field_name):
            return getattr(cls, result_field_name)

        if not cls or not result_field_name:
            return self.fget(cls)

        setattr(cls, result_field_name, self.fget(cls))
        return getattr(cls, result_field_name)

    def getter(self, method):
        self.fget = method
        return self