Python：附加MIME编码的文本文件

Question

After a bunch of fiddling, I finally hit upon the magical sequence to attach a text file to an email (many thanks to previous posts on this service).

I'm left wondering what the lines:

attachment.add_header('Content-Disposition'. . .)

--and--

e_msg = MIMEMultipart('alternative')

actually do.

Can someone unsilence the Mimes for me please (sorry couldn't resist)

import smtplib
from email import Encoders
from email.message import Message
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

smtp_server = "1.2.3.4"
smtp_login = "account"
smpt_password = "password"

server = smtplib.SMTP(smtp_server)
server.login(smtp_login,smtp_password)

f = file("filename.csv")
attachment = MIMEText(f.read())
attachment.add_header('Content-Disposition', 'attachment', filename="filename.csv")
e_msg = MIMEMultipart('alternative')
e_msg.attach(attachment)
e_msg['Subject'] = 'Domestic Toll Monitor'
e_msg['From'] = smtp_account
body = 'Some nifty text goes here'
content = MIMEText(body)
e_msg.attach(content)
server.sendmail(smtp_from, smtp_to, e_msg.as_string())

Answer 1

Basically, MIME is the specification defining email structure. The Multipart structure is designed to allow for multiple types of messages and attachments to be sent within the same message. For example, an email might have a plain text version for backwards compatibility and a rich text or html formatted message for modern clients. Attachments count as a "part", and thus require their own header. In this case, you're adding a "Content-Disposition" type header for the attachment. If you're really interested in what that means, you can read the specification here . As for the "Alternative portion, you're setting the message to multipart and defining the types of parts that you have attached and how the client needs to handle them. There are some standard presets defining various scenarios, but Alternative is something of a wildcard, used when there is a part whose type might not be recognized or handled by most clients. For the record, I believe you also could have used a "Mixed" type. The nice thing about MIME is that while it is complicated, its thoroughly defined and its very easy to look up the specification.