Python 3.0 smtplib

Question

I have a very simple piece of code that I used in previous versions of Python without issues (version 2.5 and prior). Now with 3.0, the following code give the error on the login line "argument 1 must be string or buffer, not str".

import smtplib

   smtpserver = 'mail.somedomain.com'
   AUTHREQUIRED = 1                     # if you need to use SMTP AUTH set to 1
   smtpuser = '[email protected]'    # for SMTP AUTH, set SMTP username here
   smtppass = 'somepassword'            # for SMTP AUTH, set SMTP password here
   msg = "Some message to send"

   RECIPIENTS = ['[email protected]']
   SENDER = '[email protected]'

   session = smtplib.SMTP(smtpserver)

   if AUTHREQUIRED:
      session.login(smtpuser, smtppass)

   smtpresult = session.sendmail(SENDER, RECIPIENTS, msg)

Google shows there are some issues with that error not being clear, but I still can't figure out what I need to try to make it work. Suggestions included defining the username as b"username", but that doesn't seem to work either.

Answer 1

Traceback (most recent call last):
  File "smtptest.py", line 18, in <module>
    session.login(smtpuser, smtppass)
  File "c:\Python30\lib\smtplib.py", line 580, in login
    AUTH_PLAIN + " " + encode_plain(user, password))
  File "c:\Python30\lib\smtplib.py", line 545, in encode_plain
    return encode_base64("\0%s\0%s" % (user, password))
  File "c:\Python30\lib\email\base64mime.py", line 96, in body_encode
    enc = b2a_base64(s[i:i + max_unencoded]).decode("ascii")
TypeError: b2a_base64() argument 1 must be bytes or buffer, not str

Your code is correct. This is a bug in smtplib or in the base64mime.py. You can track the issue here: http://bugs.python.org/issue5259

Hopefully the devs will post a patch soon.

Answer 2

UPDATE: just noticed from a look at the bug tracker there's a suggested fix also:

Edit smtplib.py and replace the existing encode_plain() definition with this:

def encode_plain(user, password):
    s = "\0%s\0%s" % (user, password)
    return encode_base64(s.encode('ascii'), eol='')

Tested here on my installation and it works properly.

Answer 3

As a variation on Jay's answer, rather than edit smtplib.py you could "monkey patch" it at run time.

Put this somewhere in your code:

def encode_plain(user, password):
    s = "\0%s\0%s" % (user, password)
    return encode_base64(s.encode('ascii'), eol='')

import smtplib
encode_plain.func_globals = vars(smtplib)
smtplib.encode_plain = encode_plain

This is kind of ugly but useful if you want to deploy your code onto other systems without making changes to their python libraries.

Answer 4

This issue has been addressed in Python3.1. Get the update at http://www.python.org/download/releases/3.1/