connexion as an extension

api.py

import pathlib
from connexion.api import Api, Resolver
import werkzeug.exceptions


def swagger_blueprint(specification, specification_dir=None, validate_responses=False,
            strict_validation=False, resolver_error=None,
            base_path='', debug=False):
    resolver = Resolver()
    swagger_json = False
    swagger_ui = False
    swagger_path = None
    swagger_url = None
    auth_all_paths = False
    arguments = dict()
    specification_dir = pathlib.Path(specification_dir)
    specification = specification_dir / specification
    resolver_error_handler = None
    validator_map = None

    api = Api(specification=specification,
                base_url=base_path, arguments=arguments,
                swagger_json=swagger_json,
                swagger_ui=swagger_ui,
                swagger_path=swagger_path,
                swagger_url=swagger_url,
                resolver=resolver,
                resolver_error_handler=resolver_error_handler,
                validate_responses=validate_responses,
                strict_validation=strict_validation,
                auth_all_paths=auth_all_paths,
                debug=debug,
                validator_map=validator_map)
    return api.blueprint

Note that the way to do this as of the version 1.1.15 is from connexion import Api