Python Send Mail with Attachments

sendmail.py

######
#
# short snippet to send a mail with python
#         with mail attachments
#
# - always handy to have such a code snippet
# - should work on python 2.x and 3.x
# - supports multiple recipients
# - based on https://docs.python.org/3.1/library/email-examples.html
# - please do proper error handling in production
# - some details on msg['To'] and sendmail: https://stackoverflow.com/a/8861795
#
######
import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.application import MIMEApplication


def sendmail(recv, subject, plain, html = None, attachments = []):
    '''
    simple function which sends a html mail with some attachments.
    make sure that all attachments can be read.

    usage:
    sendmail('you@email.com', 'Mail', 'Some Text', None, [
        {
            'name': 'filename.pdf',
            'file': '/path/to/a/file',
        },
    ])

    or

    sendmail(['one@email.com', 'two@email.com'], 'subject line', 'some plain text')

    '''
    # me == my email address, recv == recipient's email address
    me = 'me@email.com'
    password = 'password'
    server = 'smtp.email.com'
    port = 587
    if isinstance(recv, str):
        recv = [recv]
    try:
        # make sure that some assumptions are correct
        assert isinstance(recv, (list, tuple))
        assert plain or html
        assert isinstance(attachments, (list, tuple))
        # create message container - the correct MIME type is multipart/alternative.
        msg = MIMEMultipart() # 'alternative' - not doing it
        msg['Subject'] = '{}'.format(subject)
        msg['From'] = me
        msg['To'] = ', '.join(recv)
        # add main content
        if not plain is None:
            part = MIMEText(plain, 'plain')
            msg.attach(part)
        if not html is None:
            part = MIMEText(html, 'html')
            msg.attach(part)
        # According to RFC 2046, the last part of a multipart message, in this case
        # the HTML message, is best and preferred.
        # add attachment files
        for attachment in attachments:
            name = attachment['name']
            with open(attachment['file'], 'rb') as f:
                content = f.read()
            part = MIMEApplication(content, Name=name)
            part['Content-Disposition'] = 'attachment; filename="{}"'.format(name)
            msg.attach(part)
        # Send the message via SMTP server.
        mail = smtplib.SMTP(server, port)
        mail.ehlo()
        mail.starttls()
        mail.login(me, password)
        mail.sendmail(me, recv, msg.as_string())
        mail.quit()
        return True
    except Exception:
        return False