A simple SMTP server (in Python)

Take a look at this SMTP sink server:

from __future__ import print_function
from datetime import datetime
import asyncore
from smtpd import SMTPServer

class EmlServer(SMTPServer):
    no = 0
    def process_message(self, peer, mailfrom, rcpttos, data):
        filename = '%s-%d.eml' % (datetime.now().strftime('%Y%m%d%H%M%S'),
                self.no)
        f = open(filename, 'w')
        f.write(data)
        f.close
        print('%s saved.' % filename)
        self.no += 1


def run():
    # start the smtp server on localhost:1025
    foo = EmlServer(('localhost', 1025), None)
    try:
        asyncore.loop()
    except KeyboardInterrupt:
        pass


if __name__ == '__main__':
    run()

It uses smtpd.SMTPServer to dump emails to files.

To get Hasen's script working in Python 3 I had to tweak it slightly:

from datetime import datetime
import asyncore
from smtpd import SMTPServer

class EmlServer(SMTPServer):
    no = 0
    def process_message(self, peer, mailfrom, rcpttos, data, **kwargs):
        filename = '%s-%d.eml' % (datetime.now().strftime('%Y%m%d%H%M%S'),
            self.no)
        print(filename)
        f = open(filename, 'wb')
        f.write(data)
        f.close
        print('%s saved.' % filename)
        self.no += 1

def run():
    EmlServer(('localhost', 25), None)
    try:
        asyncore.loop()
    except KeyboardInterrupt:
        pass

if __name__ == '__main__':
    run()

There are really 2 things required to send an email:

• An SMTP Server - This can either be the Python SMTP Server or you can use GMail or your ISP's server. Chances are you don't need to run your own.
• An SMTP Library - Something that will send an email request to the SMTP server. Python ships with a library called smtplib that can do that for you. There is tons of information on how to use it here: http://docs.python.org/library/smtplib.html

For reading, there are two options depending on what server you are reading the email from.

• For a POP Email Server - You can use the poplib python library: http://docs.python.org/library/poplib.html
• For an IMAP Email Server - You can use the imaplib python library: http://docs.python.org/library/imaplib.html