def build_empty_response()

in Assets_as_Code/Assets_as_Code/boto3-1.18.59/boto3/resources/response.py [0:0]

• 22 lines of code
• 13 McCabe index (conditional complexity)

def build_empty_response(search_path, operation_name, service_model):
    """
    Creates an appropriate empty response for the type that is expected,
    based on the service model's shape type. For example, a value that
    is normally a list would then return an empty list. A structure would
    return an empty dict, and a number would return None.

    :type search_path: string
    :param search_path: JMESPath expression to search in the response
    :type operation_name: string
    :param operation_name: Name of the underlying service operation.
    :type service_model: :ref:`botocore.model.ServiceModel`
    :param service_model: The Botocore service model
    :rtype: dict, list, or None
    :return: An appropriate empty value
    """
    response = None

    operation_model = service_model.operation_model(operation_name)
    shape = operation_model.output_shape

    if search_path:
        # Walk the search path and find the final shape. For example, given
        # a path of ``foo.bar[0].baz``, we first find the shape for ``foo``,
        # then the shape for ``bar`` (ignoring the indexing), and finally
        # the shape for ``baz``.
        for item in search_path.split('.'):
            item = item.strip('[0123456789]$')

            if shape.type_name == 'structure':
                shape = shape.members[item]
            elif shape.type_name == 'list':
                shape = shape.member
            else:
                raise NotImplementedError(
                    'Search path hits shape type {0} from {1}'.format(
                        shape.type_name, item))

    # Anything not handled here is set to None
    if shape.type_name == 'structure':
        response = {}
    elif shape.type_name == 'list':
        response = []
    elif shape.type_name == 'map':
        response = {}

    return response