180010017_smtpmail.py

import socket
import sys
import argparse
from assets.core_modules.smtp.custom_smtp import is_valid_port, VALID_PORT_RANGE, SimpleMailServer
from assets.core_modules.exeptions.custom_exeptions import CustomConnectionError


def Main():
    ''' Main function to interact with user via commandline '''

    parser = argparse.ArgumentParser(description='Command Line Interface to accept port number on which server runs.')
    parser.add_argument('-p', '--port', help='The port number to be used by server', type=int, required=True)

    # Extract arguments passed from user, and verify the arguments are as expected
    args = parser.parse_args()

    # if user doesn't enter a valid port number
    if not is_valid_port(args.port):
        print(f'\tThe port number is not valid.\n\tExpecting a valid port number in range: {str(VALID_PORT_RANGE)}.\n\tPlease try again.')
        sys.exit(1)

    # The port entered by user is valid, Try creating connection
    mailserver = SimpleMailServer(port=args.port)

    try:
        print(f'Trying to bind socket on port {args.port}')
        mailserver.connect()
    except CustomConnectionError as e:
        print(f'\tThere was an error while connecting : {e}.\nPlease try again.')
        sys.exit(1)
    except Exception as e:
        print(f'Program exiting unexpectedly due to error : {e}.')
        sys.exit(1)

    # accept incoming mail requests from users and save them in database
    mailserver.accept()


if __name__ == '__main__':
    Main()