如何从电子邮件中获取有效负载并发送它们未经修改，没有主标题

Question

我需要将收件箱a@example.com中的电子邮件重新发送到b@example.org。在创建新电子邮件时，是否可以在不解码和编码的情况下发送有效负载？无论是文本、HTML还是附件。您只需从另一个邮箱发送原始信件，而无需转发通知

mail = imaplib.IMAP4_SSL(server)
mail.login(login, password)
mail.list()
mail.select("inbox")

result, data = mail.search(None, "UNSEEN")
if result == 'OK':
    for num in data[0].split():
        result, data = mail.fetch(num, "(RFC822)")
        raw_email = data[0][1]
        try:
            oldmsg = email.message_from_string(raw_email)
        except TypeError:
            oldmsg = email.message_from_bytes(raw_email)
        newmsg = email.mime.multipart.MIMEMultipart(boundary="----")
        newmsg['Subject'] = decode_mime_words(oldmsg['Subject'])
        newmsg['From'] = login
        newmsg['Date'] = strftime("%a, %d %b %Y %H:%M:%S %z")
        newmsg['User-Agent'] = "Roundcube Webmail"
        newmsg['To'] = to
        #part = MIMEBase('application', 'octet-stream')
        if oldmsg.is_multipart():
            for oldpayload in oldmsg.get_payload():
                print(oldpayload.get_payload())
                print("-_________________-")
        else:
            print(oldmsg.get_payload())

            # get attachments
        for part in oldmsg.walk():
            if part.get_content_maintype() == 'multipart':
                continue
            if part.get('Content-Disposition') is None:
                continue
            fileName = part.get_filename()
            if (fileName[:11] == '=?koi8-r?B?') or (fileName[:11] == '=?KOI8-R?B?'):
                fileName = base64.b64decode(fileName[11:]).decode(
                    'KOI8-R')
            elif (fileName[:10] == '=?utf-8?B?') or (fileName[:10] == '=?UTF-8?B?'):
                fileName = base64.b64decode(fileName[10:])
                fileName = fileName.decode('utf-8')

            # name attachemnts
            if bool(fileName):
                filePath = os.path.join('attach', fileName)
                if not os.path.isfile(filePath):
                    fp = open(filePath, 'wb')
                    fp.write(part.get_payload(decode=True))
                    part = MIMEApplication(open(filePath, 'rb').read())
                    part.add_header('Content-Disposition', 'attachment', filename=fileName)
                    newmsg.attach(part)
                    fp.close()