并非所有 MIME 文本都显示在邮件服务器上

Question

我正在使用 Python email.mime lib 编写电子邮件，我创建了两个 MIMEText 对象，然后将它们作为文本（而不是附件）附加到 Message，结果我得到了 MIME 文档，如下所示可以看到有两个文本对象，一个是plain类型，另一个是html类型，我的问题是我在某些邮件客户端中只能看到后一个文本对象（这里是html），而我可以看到两个文本其他一些邮件客户端（例如 live.com）中的对象，那么是什么原因造成的呢？

Content-Type: multipart/mixed; boundary="===============0542266593=="
MIME-Version: 1.0
FROM: john.smith@NYU.com
TO: john.smith@live.com, john.smith@gmail.com
SUBJECT: =?utf-8?q?A_Greeting_From_Postman?=

--===============0542266593==
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: base64

SGkhCkhvdyBhcmUgeW91PwpIZXJlIGlzIHRoZSBsaW5rIHlvdSB3YW50ZWQ6Cmh0dHA6Ly93d3cu
cHl0aG9uLm9yZw==

--===============0542266593==
Content-Type: text/html; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: base64

ICAgICAgICA8aHRtbD4KICAgICAgICAgIDxoZWFkPjwvaGVhZD4KICAgICAgICAgIDxib2R5Pgog
ICAgICAgICAgICA8cD5IaSE8YnI+CiAgICAgICAgICAgICAgIEhvdyBhcmUgeW91Pzxicj4KICAg
ICAgICAgICAgICAgSGVyZSBpcyB0aGUgPGEgaHJlZj0iaHR0cDovL3d3dy5weXRob24ub3JnIj5s
aW5rPC9hPiB5b3Ugd2FudGVkLgogICAgICAgICAgICA8L3A+CiAgICAgICAgICA8L2JvZHk+CiAg
ICAgICAgPC9odG1sPgogICAgICAgIA==

--===============0542266593==--

Answer 1

您已将“multipart/mixed”指定为 mime 类型。如果您只想显示一项，请指定“multipart/alternative”，如下所示：

email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.encoders import encode_base64

# Note: 'alternative' means only display one of the items. 
msg = MIMEMultipart('alternative')
msg['Subject'] = "Hello"
msg['From'] = 'me@example.com'
msg['To'] = 'you@example.com'

msg.attach(MIMEText('Hello!', 'plain'))
msg.attach(MIMEText('<b>Hello!</b>', 'html'))

# Not required, but you had it in your example, so I kept it.
for i in msg.get_payload():
    encode_base64(i)

print msg.as_string()