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service

dandy.core.service.service

TypeAny = TypeVar('TypeAny', bound=Any, covariant=True) module-attribute

BaseService

Bases: ABC, Generic[TypeAny]

Source code in dandy/core/service/service.py 
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def __init__(self, obj: Any = None):
    if self.has_obj_service_instance(obj):
        return

    self._obj_type_name: str = str(
        list(self.__class__.__annotations__.values())[0]
    ).split('.')[-1]

    if obj is None:
        return

    self._obj_mro_type_names = [cls.__name__ for cls in obj.__class__.__mro__]

    if not self._obj_type_name in self._obj_mro_type_names:
        message = f'{self.__class__.__name__} was instantiated with obj type "{obj.__class__.__name__}" and failed as it was expecting "{self._obj_type_name}".'
        raise ServiceCriticalException(message)

    self._obj_type: type[TypeAny] = obj.__class__

    if self._obj_type is None or self._obj_type is ...:
        message = f'{self.__class__.__name__} top class attribute must have an annotated type.'
        raise ServiceCriticalException(message)

    self.obj: TypeAny = obj

    if ABC not in self.__class__.__bases__:
        if not self._obj_is_valid:
            message = f'{self._obj_type_name} failed to validate on {self.__class__.__name__}'
            raise ServiceCriticalException(message)

    self.__post_init__()

    if not hasattr(obj, self.generate_service_instance_name(self.__class__)):
        message = f'To use "{self.__class__.__name__}" can only be attached to an object with a "{self.generate_service_instance_name(self.__class__)}" attribute.'
        raise ServiceCriticalException(message)

    self.set_obj_service_instance(obj, self)

obj = obj instance-attribute

obj_class property

__new__

Source code in dandy/core/service/service.py 
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def __new__(cls, obj: Any = None) -> Any:
    service_instance = cls.get_obj_service_instance(obj)

    if service_instance is not None:
        return service_instance
    else:
        return super().__new__(cls)

__init_subclass__

Source code in dandy/core/service/service.py 
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def __init_subclass__(cls):
    super().__init_subclass__()

    if ABC not in cls.__bases__:
        if 'obj' not in cls.__annotations__:
            message = f'{cls.__name__} must have an "obj" attribute annotated with a type.'
            raise ServiceCriticalException(message)

        # Typing Does not work properly for services if you override __get__ in the BaseService class.
        # This is a workaround and should be fixed in future versions of the python lsp.
        def __get__(self, instance, owner):

            if instance is None:
                target: cls | Any = owner()
            else:
                target: cls | Any = instance

            if issubclass(target.__class__, BaseService):
                self._validate_base_service_target_or_error(target)

                return cls(getattr(target, 'obj'))

            return cls(target)

        setattr(cls, '__get__', __get__)

__post_init__

Source code in dandy/core/service/service.py 
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def __post_init__(self):
    pass

generate_service_instance_name staticmethod

Source code in dandy/core/service/service.py 
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@staticmethod
def generate_service_instance_name(cls) -> str:
    return f'_{cls.__name__}_instance'

get_obj_service_instance classmethod

Source code in dandy/core/service/service.py 
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@classmethod
def get_obj_service_instance(cls, obj: Any) -> Any | None:
    return getattr(
        obj,
        cls.generate_service_instance_name(cls),
        None
    )

has_obj_service_instance

Source code in dandy/core/service/service.py 
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def has_obj_service_instance(self, obj: Any) -> bool:
    return self.get_obj_service_instance(obj) is not None

set_obj_service_instance classmethod

Source code in dandy/core/service/service.py 
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@classmethod
def set_obj_service_instance(cls, obj: Any, service_instance: BaseService):
    setattr(
        obj,
        cls.generate_service_instance_name(cls),
        service_instance
    )