How do I send attachments using SMTP?

StackOverflow https://stackoverflow.com/questions/1966073

Question

I want to write a program that sends email using Python's smtplib. I searched through the document and the RFCs, but couldn't find anything related to attachments. Thus, I'm sure there's some higher-level concept I'm missing out on. Can someone clue me in on how attachments work in SMTP?

Was it helpful?

Solution

What you want to check out is the email module. It lets you build MIME-compliant messages that you then send with smtplib.

OTHER TIPS

Here is an example of a message with a PDF attachment, a text "body" and sending via Gmail.

# Import smtplib for the actual sending function
import smtplib

# For guessing MIME type
import mimetypes

# Import the email modules we'll need
import email
import email.mime.application

# Create a text/plain message
msg = email.mime.Multipart.MIMEMultipart()
msg['Subject'] = 'Greetings'
msg['From'] = 'xyz@gmail.com'
msg['To'] = 'abc@gmail.com'

# The main body is just another attachment
body = email.mime.Text.MIMEText("""Hello, how are you? I am fine.
This is a rather nice letter, don't you think?""")
msg.attach(body)

# PDF attachment
filename='simple-table.pdf'
fp=open(filename,'rb')
att = email.mime.application.MIMEApplication(fp.read(),_subtype="pdf")
fp.close()
att.add_header('Content-Disposition','attachment',filename=filename)
msg.attach(att)

# send via Gmail server
# NOTE: my ISP, Centurylink, seems to be automatically rewriting
# port 25 packets to be port 587 and it is trashing port 587 packets.
# So, I use the default port 25, but I authenticate. 
s = smtplib.SMTP('smtp.gmail.com')
s.starttls()
s.login('xyz@gmail.com','xyzpassword')
s.sendmail('xyz@gmail.com',['xyz@gmail.com'], msg.as_string())
s.quit()

Here's an example I snipped out of a work application we did. It creates an HTML email with an Excel attachment.

  import smtplib,email,email.encoders,email.mime.text,email.mime.base

  smtpserver = 'localhost'
  to = ['email@somewhere.com']
  fromAddr = 'automated@hi.com'
  subject = "my subject"

  # create html email
  html = '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" '
  html +='"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml">'
  html +='<body style="font-size:12px;font-family:Verdana"><p>...</p>'
  html += "</body></html>"
  emailMsg = email.MIMEMultipart.MIMEMultipart('alternative')
  emailMsg['Subject'] = subject
  emailMsg['From'] = fromAddr
  emailMsg['To'] = ', '.join(to)
  emailMsg['Cc'] = ", ".join(cc)
  emailMsg.attach(email.mime.text.MIMEText(html,'html'))

  # now attach the file
  fileMsg = email.mime.base.MIMEBase('application','vnd.ms-excel')
  fileMsg.set_payload(file('exelFile.xls').read())
  email.encoders.encode_base64(fileMsg)
  fileMsg.add_header('Content-Disposition','attachment;filename=anExcelFile.xls')
  emailMsg.attach(fileMsg)

  # send email
  server = smtplib.SMTP(smtpserver)
  server.sendmail(fromAddr,to,emailMsg.as_string())
  server.quit()

Well, attachments are not treated in any special ways, they are "just" leaves of the Message-object tree. You can find the answers to any questions regarding MIME-compliant mesasges in this section of the documentation on the email python package.

In general, any kind of attachment (read: raw binary data) can be represented by using base64 (or similar) Content-Transfer-Encoding.

Here's how to send e-mails with zip file attachments and utf-8 encoded subject+body.

It was not straightforward to figure this one out, due to lack of documentation and samples for this particular case.

Non-ascii characters in replyto needs to be encoded with, for instance, ISO-8859-1. There probably exists a function that can do this.

Tip:
Send yourself an e-mail, save it and examine the content to figure out how to do the same thing in Python.

Here's the code, for Python 3:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# vim:set ts=4 sw=4 et:

from os.path import basename
from smtplib import SMTP
from email.mime.text import MIMEText
from email.mime.base import MIMEBase
from email.mime.multipart import MIMEMultipart
from email.header import Header
from email.utils import parseaddr, formataddr
from base64 import encodebytes

def send_email(recipients=["somebody@somewhere.xyz"],
         subject="Test subject æøå",
         body="Test body æøå",
         zipfiles=[],
         server="smtp.somewhere.xyz",
         username="bob",
         password="password123",
         sender="Bob <bob@somewhere.xyz>",
         replyto="=?ISO-8859-1?Q?M=F8=F8=F8?= <bob@somewhere.xyz>"): #: bool
    """Sends an e-mail"""
    to = ",".join(recipients)
    charset = "utf-8"
    # Testing if body can be encoded with the charset
    try:
        body.encode(charset)
    except UnicodeEncodeError:
        print("Could not encode " + body + " as " + charset + ".")
        return False

    # Split real name (which is optional) and email address parts
    sender_name, sender_addr = parseaddr(sender)
    replyto_name, replyto_addr = parseaddr(replyto)

    sender_name = str(Header(sender_name, charset))
    replyto_name = str(Header(replyto_name, charset))

    # Create the message ('plain' stands for Content-Type: text/plain)
    try:
        msgtext = MIMEText(body.encode(charset), 'plain', charset)
    except TypeError:
        print("MIMEText fail")
        return False

    msg = MIMEMultipart()

    msg['From'] = formataddr((sender_name, sender_addr))
    msg['To'] = to #formataddr((recipient_name, recipient_addr))
    msg['Reply-to'] = formataddr((replyto_name, replyto_addr))
    msg['Subject'] = Header(subject, charset)

    msg.attach(msgtext)

    for zipfile in zipfiles:
        part = MIMEBase('application', "zip")
        b = open(zipfile, "rb").read()
        # Convert from bytes to a base64-encoded ascii string
        bs = encodebytes(b).decode()
        # Add the ascii-string to the payload
        part.set_payload(bs)
        # Tell the e-mail client that we're using base 64
        part.add_header('Content-Transfer-Encoding', 'base64')
        part.add_header('Content-Disposition', 'attachment; filename="%s"' %
                        os.path.basename(zipfile))
        msg.attach(part)

    s = SMTP()
    try:
        s.connect(server)
    except:
        print("Could not connect to smtp server: " + server)
        return False

    if username:
        s.login(username, password)
    print("Sending the e-mail")
    s.sendmail(sender, recipients, msg.as_string())
    s.quit()
    return True

def main():
    send_email()

if __name__ == "__main__":
    main()

# -*- coding: utf-8 -*-

"""
Mail sender
"""

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

import smtplib
import pystache
import codecs
import time

import sys
reload(sys)
sys.setdefaultencoding('utf-8')


HOST = 'smtp.exmail.qq.com'
PORT = 587
USER = 'your@mail.com'
PASS = 'yourpass'
FROM = 'your@mail.com'

SUBJECT = 'subject'
HTML_NAME = 'tpl.html'
CSV_NAME = 'list.txt'
FAILED_LIST = []


def send(mail_receiver, mail_to):
    # text = mail_text
    html = render(mail_receiver)

    # msg = MIMEMultipart('alternative')
    msg = MIMEMultipart('mixed')
    msg['From'] = FROM
    msg['To'] = mail_to.encode()
    msg['Subject'] = SUBJECT.encode()

    # msg.attach(MIMEText(text, 'plain', 'utf-8'))
    msg.attach(MIMEText(html, 'html', 'utf-8'))

    try:
        _sender = smtplib.SMTP(
            HOST,
            PORT
        )
        _sender.starttls()
        _sender.login(USER, PASS)
        _sender.sendmail(FROM, mail_to, msg.as_string())
        _sender.quit()
        print "Success"
    except smtplib.SMTPException, e:
        print e
        FAILED_LIST.append(mail_receiver + ',' + mail_to)


def render(name):
    _tpl = codecs.open(
        './html/' + HTML_NAME,
        'r',
        'utf-8'
    )
    _html_string = _tpl.read()
    return pystache.render(_html_string, {
        'receiver': name
    })


def main():
    ls = open('./csv/' + CSV_NAME, 'r')
    mail_list = ls.read().split('\r')

    for _receiver in mail_list:
        _tmp = _receiver.split(',')
        print 'Mail: ' + _tmp[0] + ',' + _tmp[1]
        time.sleep(20)
        send(_tmp[0], _tmp[1])

    print FAILED_LIST


main()
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