def download()

in source/backend/src/transfer_sftp_backend.py [0:0]

• 50 lines of code
• 7 McCabe index (conditional complexity)

def download():
    try:
        logger.info(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): Request received')
        sftp_hostname = app.config.get('sftp_hostname')
        usr, passwd = authenticate_request(request)

        request_data = request.get_json()

        filepath = request_data['path']
        logger.info(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): File Path: {filepath}')
        filename = str(filepath).split('/')[-1]  # Returns the filename

        sftp_connection = get_sftp_connection(usr, passwd, sftp_hostname)
        download_scratch_space_path = '/var/sftp-download-scratch-space'

        if (os.path.exists(download_scratch_space_path) == False):
            logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): download scratch path {download_scratch_space_path} does not exist. Creating it ')
            os.mkdir(download_scratch_space_path)
            logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): created the {download_scratch_space_path} path')
        else:
            logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): download scratch path {download_scratch_space_path} exists ')
            listfolders = os.listdir(download_scratch_space_path)
            logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): List of existing folders (should be empty) : {listfolders} ')

        # create unique temp path for the file
        temppath = download_scratch_space_path + '/' + str(uuid.uuid4().hex) + '_' + str(
            datetime.datetime.utcnow().timestamp()).replace('.', '_')
        logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): temp path to be created : {temppath}')
        if (os.path.exists(temppath)):
            logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): download temp path already exists')
            os.rmdir(temppath)
            logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): deleted the existing download temp path')
            os.mkdir(temppath)
            logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): created the download temp path again')
        else:
            logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): download temp path does not exists. Creating new one')
            os.mkdir(temppath)

        remote_path = filepath
        local_path = temppath + "/" + filename
        # Getting file from SFTP endpoint
        sftp_connection.get(remote_path, local_path, callback=None)

        logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): sending file : remote path: {remote_path} local_path: {local_path}')

        # Remove the temp path and the file from the local storage after it is sent to the client
        @after_this_request
        def remove_temp_path(response):
            try:
                os.remove(local_path)
                os.rmdir(temppath)
                logger.debug(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): removed temp path after_this_request')
            except Exception as e:
                logger.error(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): Download operation after_this_request error occurred : {e}')
                return bad_request(e, 500)
            return response

        logger.info(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): Responding back with 200 status code')
        return send_file(local_path, as_attachment=True, attachment_filename=filename)

    except Exception as e:
        logger.error(f'TaskID: {fargate_task_id}(PID:{pid}) - download(): call to /api/download returned exception {e}')
        return bad_request("Bad or Invalid Request", 500)