helpers.py 文件源码

def get_subclasses(class_type, directory=None):
    """
    Creates a dictionary of classes which inherit from ``class_type`` found in
    all python files within a given directory, keyed by the class name in snake
    case as a string.

    :param class_type: The base class that all returned classes should inherit
        from.
    :type class_type: cls
    :param directory: The directory to look for classes in.
    :type directory: str
    :returns: A dict of classes found.
    :rtype: dict
    """
    try:
        glob_expression = os.path.join(directory, "*.py")
    except (AttributeError, TypeError):
        raise TypeError("'directory' object should be a string")

    module_paths = glob.glob(glob_expression)

    sys.path.append(directory)

    modules = [
        imp.load_source(
            os.path.basename(module_path).split(".")[0], module_path
        )
        for module_path in module_paths
        if "__init__" not in module_path
    ]

    classes = {}

    for module in modules:
        for attr in module.__dict__.values():
            if inspect.isclass(attr) \
                and issubclass(attr, class_type) \
                    and not inspect.isabstract(attr):
                        classes[camel_to_snake_case(attr.__name__)] = attr

    return classes