Attribute Lookup

getter.py

import sys

class CommonAttributes:

    def __init__(self):
        self.name = 'common'

class MissingAttributes:

    def __init__(self):
        self.name = 'missing'

class GetterSpecialMethods(CommonAttributes):
    name = 'class variable'

    def __init__(self):
        super().__init__()
        this_func = sys._getframe().f_code.co_name
        print(f'Called {this_func} method to initialize class')
        self.name = 'Suresh'

    def __getattribute__(self, item):
        this_func = sys._getframe().f_code.co_name
        print(f'Called overridden method {this_func} for attribute lookup')
        if item not in super().__dict__:
            raise AttributeError(f'Attribute not found via {this_func}')
        # any other exception will abort, AttributeError will cause the lookup to continue via __getattr__
        return super().__dict__.get(item)

    def __getattr__(self, item):
        this_func = sys._getframe().f_code.co_name
        print(f'Called {this_func} for missing attribute')
        if item not in MissingAttributes().__dict__:
            raise AttributeError(f'Attribute not found via {this_func}')
        MissingAttributes().__dict__.get(item)


    def __getitem__(self, item):
        this_func = sys._getframe().f_code.co_name
        print(f'Called {this_func} for subscript notation')
        return self.__dict__.get(item)

    # def __get__(self, instance, owner):
    #     pass

    #
    # def __getinitargs__(self):
    #     pass
    #
    # def __getnewargs__(self):
    #     pass
    #

    # def __getstate__(self):
    #     pass

getter_obj = GetterSpecialMethods()
print(getter_obj.name)
print(getter_obj.name_not_found)
print(getter_obj['name'])