python. Can I check if SMTP Server is disconnected (so I can connect again?)

Question

I am using smtplib and I am sending notification emails from my application. However I noticed that sometimes (especially when there is a lot of idle time between mail sending) I get a SMTPServerDisconnected error.

I guess there are 2 solutions for this (know none of them, though)

1. Increase idle time between sending mails
2. reconnect when connection is down.

I think 2nd solution seems more elegant. But how can I do that?

edit: I am adding the code

from smtplib import SMTP
smtp = SMTP()
smtp.connect('smtp.server.com')
smtp.login('username','password')

def notifyUser():
    smtp.sendmail(from_email, to_email, msg.as_string())

Answer 1

Yes, you can check if the connection is open. To do this, issue a NOOP command and test for status == 250. If not, then open the connection before sending out your mail.

def test_conn_open(conn):
    try:
        status = conn.noop()[0]
    except:  # smtplib.SMTPServerDisconnected
        status = -1
    return True if status == 250 else False

def send_email(conn, from_email, to_email, msg):
   if not test_conn_open(conn):
       conn = create_conn()
   conn.sendmail(from_email, to_email, msg.as_string())
   return conn    # as you want are trying to reuse it.

Note that you are doing this as opening a connection, say with gmail, consumes time, like 2-3 secs. Subsequently, to optimize on sending multiple emails that you may have at hand, then you should also follow Pedro's response (last part).