Sends a multipart/alternative email containing 3 parts: text/plain, text/html and text/x-other.

multipart_email.py

#!/usr/bin/python3

# Copyright 2018 Google LLC.
# SPDX-License-Identifier: Apache-2.0

# Sends a multipart/alternative email containing 3 parts: text/plain, text/html and text/x-other.

import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

SUBJECT = 'Test email'
SENDER = 'johndoe@example.com'

SMTP_SERVER = 'smtp.gmail.com:587'
SMTP_USERNAME = 'user@gmail.com'
SMTP_PASSWORD = ''

def CreateEmail(recipient):
  payload = MIMEMultipart('alternative')
  payload['Subject'] = SUBJECT
  payload['From'] = SENDER
  payload['To'] = recipient
  payload.attach(MIMEText('text version', 'plain'))
  payload.attach(MIMEText('<b>html version</b>', 'html'))
  payload.attach(MIMEText('this shouldn\'t be displayed', 'x-other'))

  return payload

def SendPayloadViaSMTP(payload):
  smtp = smtplib.SMTP(SMTP_SERVER)
  try:
    smtp.ehlo()
    smtp.starttls()
    smtp.login(SMTP_USERNAME, SMTP_PASSWORD)
    smtp.sendmail(payload['From'], payload['To'], payload.as_string())
  except Exception as e:
    print('SMTP Exception:\n' + str(e))
  finally:
    smtp.quit()

def main():
  email = CreateEmail('user@domain.com')
  SendPayloadViaSMTP(email)

if __name__ == "__main__":
  main()