Program which send email via Python exits with "AttributeError: 'str' object has no attribute 'get_content_maintype''"

Question

I have python code intended to send an email with an attachment, and I've come down to this:

#!/usr/bin/python
import os, re
import sys
import smtplib

#from email.mime.image import MIMEImage
from email.mime.multipart import MIMEMultipart
from email.MIMEText import MIMEText


SMTP_SERVER = 'smtp.gmail.com'
SMTP_PORT = 587

sender = '[email protected]'
password = "e45dt4iamkiddingthisisnotmypassword"
recipient = '[email protected]'
subject = 'Python emaillib Test'
message = 'Images attached.'

def main():
    msg = MIMEMultipart()
    msg['Subject'] = 'Python emaillib Test'
    msg['To'] = recipient
    msg['From'] = sender

    msg.attach('/tmp/images/a.gif')

    part = MIMEText('text', "plain")
    part.set_payload(message)
    msg.attach(part)

    session = smtplib.SMTP(SMTP_SERVER, SMTP_PORT)

    session.ehlo()
    session.starttls()
    session.ehlo

    session.login(sender, password)

#    my_message=msg.as_string()
    qwertyuiop=msg
    session.sendmail(sender, recipient, qwertyuiop.as_string())

    session.quit()

if __name__ == '__main__':
    main()

And I get this error when running:

Traceback (most recent call last):
  File "./abcd.py", line 49, in <module>
    main()
  File "./abcd.py", line 44, in main
    session.sendmail(sender, recipient, qwertyuiop.as_string())
  File "/usr/lib/python2.7/email/message.py", line 137, in as_string
    g.flatten(self, unixfrom=unixfrom)
  File "/usr/lib/python2.7/email/generator.py", line 83, in flatten
    self._write(msg)
  File "/usr/lib/python2.7/email/generator.py", line 108, in _write
    self._dispatch(msg)
  File "/usr/lib/python2.7/email/generator.py", line 134, in _dispatch
    meth(msg)
  File "/usr/lib/python2.7/email/generator.py", line 203, in _handle_multipart
    g.flatten(part, unixfrom=False)
  File "/usr/lib/python2.7/email/generator.py", line 83, in flatten
    self._write(msg)
  File "/usr/lib/python2.7/email/generator.py", line 108, in _write
    self._dispatch(msg)
  File "/usr/lib/python2.7/email/generator.py", line 125, in _dispatch
    main = msg.get_content_maintype()
AttributeError: 'str' object has no attribute 'get_content_maintype'

I assume that it has to do with msg.attach("/tmp/images/a.gif") but I'm not sure. The source of the problem is qwertyuiop.as_string() though.

Solution

The problem is that msg.attach() attaches another message, not a string/filename. You need to create a MIMEImage object and attach that:

# instead of msg.attach('/tmp/images/a.gif')...
fp = open('/tmp/images/a.gif', 'rb')
msgImage = MIMEImage(fp.read())
fp.close()
msg.attach(msgImage)

Example adapted from here

If you want types other than Images, check out http://docs.python.org/library/email.mime.html.

The reason you're getting the error on the qwertyuiop.as_string() line is that the message isn't parsed until you call as_string().