def resource_file_format(value):
    """Space-separated resource references in filename=httpurl format."""
    try:
        file_name, http_url = value.split('=', 1)
    except ValueError:
        message = (
            'Incorrectly formatted resource reference. Argument values should be in the format filename=httpurl'
            )
        raise ValueError(message)
    return {'file_path': file_name, 'http_url': http_url}
