python - 如何在 Python 中访问父类(super class)的元属性？

Question

我有一些这样的代码 Django-Tastypie :

class SpecializedResource(ModelResource):
    class Meta:
        authentication = MyCustomAuthentication()

class TestResource(SpecializedResource):
    class Meta:
        # the following style works:
        authentication = SpecializedResource.authentication
        # but the following style does not:
        super(TestResource, meta).authentication

我想知道在不对父类(super class)名称进行硬编码的情况下访问父类(super class)元属性的正确方法是什么。

Answer 1

在您的示例中，您似乎试图覆盖父类(super class)的元属性。为什么不使用元继承？

class MyCustomAuthentication(Authentication):
    pass

class SpecializedResource(ModelResource):
    class Meta:
        authentication = MyCustomAuthentication()

class TestResource(SpecializedResource):
    class Meta(SpecializedResource.Meta):
        # just inheriting from parent meta
        pass
    print Meta.authentication

输出:

<__main__.MyCustomAuthentication object at 0x6160d10> 

因此 TestResource 的 meta 是从父元(这里是身份验证属性)继承的。

终于回答问题了:

如果您真的想访问它(例如将内容附加到父列表等)，您可以使用您的示例:

class TestResource(SpecializedResource):
    class Meta(SpecializedResource.Meta):
        authentication = SpecializedResource.Meta.authentication # works (but hardcoding)

或者没有硬编码 super 类:

class TestResource(SpecializedResource):
    class Meta(SpecializedResource.Meta):
        authentication = TestResource.Meta.authentication # works (because of the inheritance)