Knowing whether or not FTP is still connected with ftplib

Question

I was wondering if there is an easy way of knowing whether a connection to an FTP server is still active using ftplib.

So if you have an active connection like this:

import ftplib
ftp = ftplib.FTP("ftp.myserver.com", "admin", "pass123")

is there something like the following pseudo code that can be queried to check if the connection is still active?

if ftp.is_connected() == True:
    print "Connection still active"
else:
    print "Disconnected"

Answer 1

You could try retrieving something from the server, and catching any exceptions and returning whether or not it's connected based on that.

For example:

def is_connected(ftp_conn):
    try:
        ftp_conn.retrlines('LIST')
    except (socket.timeout, OSError):
        return False
    return True

This simple example will print the 'LIST' results to stdout, you can change that by putting your own callback into the retrlines method

---

(Make sure you set a timeout in the initial FTP object construction, as the default is for it to be None.)

ftp = ftplib.FTP("ftp.gnu.org", timeout=5, user='anonymous', passwd='')