aeduG aeduG - 27 days ago 8
Python Question

Forward email message to remote smtp server in Python

I want to create a SMTP-Gateway that filters emails and redirects them to the remote SMTP server.

from smtpd import SMTPServer
from email.parser import Parser

class SMTPGateway(SMTPServer):

def process_message(self, peer, mailfrom, rcpttos, data, **kwargs):
print('Processing message...')

email = Parser().parsestr(data)
for part in email.walk():
if part.get_content_maintype() == 'text':
text = part.get_payload()
# Process text

# forward email to upstream smtp server


With this code I can receive a message and process it. But I don't know how to forward the message to the remote server.

In my main program, I create the server like this:

localaddress = ('localhost', 3000)
remoteaddress = ('localhost', 9000)

gateway = SMTPGateway(localaddress, remoteaddress)


How can I redirect the message in
process_message
to the remote server?


The documentation of the SMTP-Server is very short:
https://docs.python.org/2/library/smtpd.html.
I could not find the answer there.

Answer

I found the answer myself.

from smtpd import SMTPServer
from email.parser import Parser

class SMTPGateway(SMTPServer):
def process_message(self, peer, mailfrom, rcpttos, data, **kwargs):
    print('Processing message...')

    email = Parser().parsestr(data)
    for part in email.walk():
        if part.get_content_maintype() == 'text':
            text = part.get_payload()
            # Process text

    # forward email to upstream smtp server
    ip = self._remoteaddr[0]
    port = self._remoteaddr[1]
    server = SMTP(ip, port)
    server.send_message(email)
    server.quit()
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