用python解码utf-8电子邮件附件文件名？

我收到一封带有附件名的电子邮件，附件名如下：

=?UTF-8?b?cmVhbF9hdHRhY2htZW50X25hbWUueGxz?=

但是，如果我查看Gmail中的原始文件，它显示如下：

------=_Part_1264195_253682143.1529181492460
Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="real_attachment_name.xls"


------=_Part_1264195_253682143.1529181492460--

for part in mail.walk():
    if part.get_content_maintype() == 'multipart' or part.get('Content-Disposition') is None:
        continue

    filename = part.get_filename()

    # Find non-ascii filenames and decode

    transfer_encoding = part.get_all('Content-Transfer-Encoding')
    if transfer_encoding and transfer_encoding[0] == 'base64':
        filename_parts = filename.split('?')
        filename = base64.b64decode(filename_parts[3]).decode(filename_parts[1])

---

我如何才能找到真正的附件名？

之所以会出现这种情况，是因为电子邮件不支持utf-8，所以它有点像是预兆。这里发生的事情是

内容传输编码

标题告诉您有一些

base64

内容正在进行，您需要按如下方式解码文件名：

------=_Part_1264195_253682143.1529181492460
Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="real_attachment_name.xls"


------=_Part_1264195_253682143.1529181492460--

for part in mail.walk():
    if part.get_content_maintype() == 'multipart' or part.get('Content-Disposition') is None:
        continue

    filename = part.get_filename()

    # Find non-ascii filenames and decode

    transfer_encoding = part.get_all('Content-Transfer-Encoding')
    if transfer_encoding and transfer_encoding[0] == 'base64':
        filename_parts = filename.split('?')
        filename = base64.b64decode(filename_parts[3]).decode(filename_parts[1])

---

所以，你实际上没有任何问题？那么这有什么意义呢？@Eypros这是我遇到并解决的一个问题，我决定同时添加问题和答案以帮助其他人：：-）