Click Download File Function for Efficient File Downloading

def click_download_file(self, urn, path):
    'Click download button, download file'
    downloaded_files_success = list()  # Download successful file list
    downloaded_files_failed = list()  # Download failed file list
    links = self.browser.safe_get_link(By.CSS_SELECTOR, ATTACHMENT_VIEW_WINDOW_ELEMENT)
    for link in links:
        # Get file name and size
        file_title, download_time_min, download_time_max, file_size = self.file_title_data(link, urn)
        file_downloaded = False
        download_attempts = 0
        while not file_downloaded and download_attempts < 3:
            if download_attempts == 0:
                download_time = download_time_min
            else:
                download_time = download_time_max
            self.browser.click_with_link(link)
            self.download_alert()  # File download is too large
            logger.info(
                '
 >> 【urn = {}】文件名{}文件大小{},下载时间{}'.format(urn, file_title, file_size, download_time))
            time.sleep(download_time)  # File download time
            # File download
            status = self.download_file_is_successfully(path, file_title, download_time)
            if status:
                downloaded_files_success.append(file_title)  # Download successful
                file_downloaded = True
            else:
                logger.info('
 >> 【urn = {}】文件{}重试下载失败'.format(urn, file_title))
                download_attempts += 1

        if not file_downloaded:
            downloaded_files_failed.append(file_title)  # Download failed

    if downloaded_files_failed:
        logger.info('
 >> 【urn = {}】下载失败文件列表：{}'.format(urn, downloaded_files_failed))
        raise FileException(message=ErrorMsg.NO_DOWNLOADABLE_FILES, file_list=downloaded_files_failed)
    if downloaded_files_success:
        logger.info('
 >> 【urn = {}】下载成功文件列表：{}'.format(urn, downloaded_files_success))
        new_file_title = self.modify_file(path, urn, downloaded_files_success)  # Download successful file name modification
        return new_file_title


def download_file_is_successfully(cls, path, file_name, download_time):
    'Whether the file is downloaded successfully'
    file_path = os.path.join(path, file_name)
    file_path_with_suffix = file_path + '.crdownload'
    last_size = 0
    while os.path.exists(file_path_with_suffix):
        cur_size = os.path.getsize(file_path_with_suffix)
        speed = cur_size - last_size
        last_size = cur_size
        if speed > 0:
            time.sleep(download_time)
        else:
            return False
    if os.path.exists(file_path):  # File exists
        return True

    return False


def file_title_data(self, link, urn):
    'Get file information: file name, size'
    title = link.get_attribute('title')

    file_titles = re.findall(REG, title)
    if not file_titles:
        file_titles = re.findall(CHINE_REG, title)
    if len(file_titles) == 0:
        QueryResult.update(UPDATE_INVOICES_SQL, (generate_utils.get_strtime(), urn))
    file_title = file_titles[0].strip()  # File name
    # [Original File] 230324043.eml  (14159) kB
    file_size_str = title.split('(')[1].split(')')[0].strip()
    file_size = int(file_size_str)  # File size
    download_time_min, download_time_max = self.calculate_download_time_limit(file_size)  # Download time
    download_time_min = min(download_time_min, 60)

    return file_title, download_time_min, download_time_max, file_size