Here, we attempt to download the first email message from a user's Google email account. The username is supplied from a command line, but the password is kept secret and not passed from the command line. This is rather entered while the script is running and kept hidden from display.

Listing 5.4 shows how to download our Google email via POP3 as follows:

#!/usr/bin/env python 
# Python Network Programming Cookbook, Second Edition -- Chapter - 5 
# This program is optimized for Python 2.7.12 and Python 3.5.2. 
# It may run on any other version with/without modifications. 
 
import argparse 
import getpass 
import poplib 
 
GOOGLE_POP3_SERVER = 'pop.googlemail.com' 
 
def download_email(username):  
    mailbox = poplib.POP3_SSL(GOOGLE_POP3_SERVER, '995')  
    mailbox.user(username) 
    password = getpass.getpass(prompt="Enter your Google password: ")  
    mailbox.pass_(password)  
    num_messages = len(mailbox.list()[1]) 
    print ("Total emails: %s" %num_messages) 
    print ("Getting last message") 
    for msg in mailbox.retr(num_messages)[1]: 
        print (msg) 
    mailbox.quit() 
 
if __name__ == '__main__': 
    parser = argparse.ArgumentParser(description='Email Download Example') 
    parser.add_argument('--username', action="store", 
    dest="username", default=getpass.getuser()) 
    given_args = parser.parse_args()  
    username = given_args.username 
    download_email(username) 

If you run this script, you will see an output similar to the following one. The message is truncated for the sake of privacy:

$ python 5_4_download_google_email_via_pop3.py --username=<USERNAME>
Enter your Google password: 
Total emails: 333
Getting last message
...[TRUNCATED]