def _get_resource(resource):
    if resource is not None:
        if os.path.isfile(resource):
            with util.open_file(resource) as resource_file:
                return util.load_json(resource_file)
        else:
            try:
                http.silence_requests_warnings()
                req = http.get(resource)
                if req.status_code == 200:
                    data = b''
                    for chunk in req.iter_content(1024):
                        data += chunk
                    return util.load_jsons(data.decode('utf-8'))
                else:
                    raise Exception
            except Exception:
                logger.exception('Cannot read from resource %s', resource)
                raise DCOSException(
                    "Can't read from resource: {0}.\n"
                    "Please check that it exists.".format(resource))

    # Check that stdin is not tty
    if sys.stdin.isatty():
        # We don't support TTY right now. In the future we will start an
        # editor
        raise DCOSException(
            "We currently don't support reading from the TTY. Please "
            "specify an application JSON.\n"
            "E.g.: dcos marathon app add < app_resource.json")

    return util.load_json(sys.stdin)
:param resource: optional filename or http(s) url
dataset/ETHPy150Open dcos/dcos-cli/cli/dcoscli/marathon/main.py/_get_resource