Python 3 EmailMessage html message with Image

Question

I am trying to get images shown as part of the mail sent with Python. There is a example on Python docs which is not working.

from datetime import datetime
import sys

import smtplib

from email.message import EmailMessage
from email.headerregistry import Address
from email.utils import make_msgid



from email.mime.image import MIMEImage

attachment = '/user/file/test.png'


import email.policy
msg = EmailMessage()
msg['To'] = Address("Srujan", '[email protected]')
msg['From'] = Address("Srujan", '[email protected]')
msg['Subject'] = "Nice message goes with it "+str(datetime.now())
id = make_msgid()
msg.set_type('text/html')
msg.set_content(" This is the Data Message that we want to send")
html_msg = "<br> <b><u> This is the Text .... </u></b><br> <img src='cid:{image_id}' />".format(image_id=id[1:-1])
msg.add_alternative(html_msg, subtype="html")
image_data = open(attachment, "rb")
image_mime = MIMEImage(image_data.read())
image_data.close()
msg.add_attachment(image_mime,   cid=id, filename = "myown.png" ,)


try:
    with smtplib.SMTP('example.com') as s:
        s.ehlo()
        s.starttls()
        s.ehlo()
        
        s.send_message(msg)
        s.close()
    print("Email sent!")
except:
    print("Unable to send the email. Error: ", sys.exc_info()[0])
    raise

I noticed that the last part is a message/rfc822, which then contains the image/png.

To: Srujan <"[email protected]"> From: Srujan
<"[email protected]"> Subject: Nice message goes with it 2016-01-21
17:39:23.642762 MIME-Version: 1.0 Content-Type: multipart/mixed;
boundary="===============3463325241650937591=="

--===============3463325241650937591==
Content-Type: multipart/alternative; boundary="===============0739224896516732414=="

--===============0739224896516732414==
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit

 This is the Data Message that we want to send

--===============0739224896516732414==
Content-Type: text/html; charset="utf-8"
Content-Transfer-Encoding: 7bit MIME-Version: 1.0

<br> <b><u> This is the Text .... </u></b><br> <img
src='cid:20160122013923.64205.76661' />

--===============0739224896516732414==--

--===============3463325241650937591==
Content-Type: message/rfc822
Content-Transfer-Encoding: 8bit
Content-Disposition: attachment; filename="myown.png"
Content-ID: <20160122013923.64205.76661>
MIME-Version: 1.0

Content-Type: image/png
MIME-Version: 1.0
Content-Transfer-Encoding: base64

iVBORw0KGgoAAAANSUhEUgAAAyAAAAJYCAIAAAAVFBUnAAAABmJLR0QA/wD/AP+gvaeTAAAgAElE
QVR4nOzdd2BUVfYH8HNfmZJAChAEQ1FAqoKgCAsWLEgTG4gKP11FQNG1AauIgGBXVhRUsCK4i6gI

Now the attached message has two content-type values. Email comes with just text and with no image.

I have done it successfully with MultiPart class, but looking to achieve that with EmailMessage.

Answer 1

It is really a pity that Python docs on this subject are incomplete/wrong. I wanted to do the same thing and got the same problem (attachments got two content-types)

Solved the problem by using the attach() method instead of add_attachment() on EmailMessage objects. The only caveat is that you have to transform the EmailMessage to multipart/mixed type before doing this. An example:

from smtplib import SMTP
from email.message import EmailMessage
from email.mime.text import MIMEText
from email.headerregistry import Address
from ssl import SSLContext, PROTOCOL_TLSv1_2

# Creating and populating email data:
msg = EmailMessage()
msg['From'] = Address(display_name='Recipient', addr_spec='[email protected]')
msg['To'] = Address(display_name='Sender', addr_spec='[email protected]')
msg['Subject'] = 'An email for you'    
msg.set_content('This should be in the email body')  
# It is possible to use msg.add_alternative() to add HTML content too  

# Attaching content:
att = MIMEText('This should be in an attached file') # Or use MIMEImage, etc
# The following line is to control the filename of the attached file
att.add_header('Content-Disposition', 'attachment', filename='attachment.txt')
msg.make_mixed() # This converts the message to multipart/mixed
msg.attach(att) # Don't forget to convert the message to multipart first!

# Sending the email:
with SMTP(host='smtp.example.org', port=587) as smtp_server:
    try:
        # You can choose SSL/TLS encryption protocol to use as shown
        # or just call starttls() without parameters
        smtp_server.starttls(context=SSLContext(PROTOCOL_TLSv1_2))
        smtp_server.login(user='[email protected]', password='password')
        smtp_server.send_message(msg)

    except Exception as e:                
        print('Error sending email. Details: {} - {}'.format(e.__class__, e))