Send gmails using command-line

gmail.py

#!/usr/bin/env python

import io
import sys
import yaml
import pathlib
import argparse
import smtplib
import getpass


def send_email(user, pwd, recipient, subject, body):
    gmail_user = user
    gmail_pwd = pwd
    FROM = user
    TO = recipient if type(recipient) is list else [recipient]
    SUBJECT = subject
    TEXT = body

    # Prepare actual message
    message = """From: %s\nTo: %s\nSubject: %s\n\n%s
    """ % (FROM, ", ".join(TO), SUBJECT, TEXT)
    try:
        server = smtplib.SMTP("smtp.gmail.com", 587)
        server.ehlo()
        server.starttls()
        server.login(gmail_user, gmail_pwd)
        server.sendmail(FROM, TO, message)
        server.close()
        print('successfully sent the mail')
    except Exception as e:
        sys.stderr.write("failed to send mail\n")
        sys.stderr.write(e + "\n")


def create_parser():
    parser = argparse.ArgumentParser(
        description="Send gmails using command lines. (Recommended) Set-up a "
                    "file at ~/.gmailrc that contains your gmail username and "
                    "password. Also, don't forget to set-up an 'Application-"
                    "specific password' to minimize security risk. Find more "
                    "information at https://support.google.com/mail/answer/185833?hl=en"
    )
    parser.add_argument("-t", "--to", 
                        help="Recipient of the email. If not provided, the "
                             "mail will be sent to the username instead.")
    parser.add_argument("-s", "--subject", default="", 
                        help="Subject of the email.")
    parser.add_argument("-b", "--body", default="", 
                        help="Contents of the email.")
    parser.add_argument("-u", "--username", 
                        help="Gmail username. Specifying this option will "
                             "override the username read from ~/.gmailrc.")
    parser.add_argument("-p", "--password", action="store_true",
                        help="Gmail password. Specifying this option will " 
                             "override the password read from ~/.gmailrc.")
    return parser


def main(args):
    username, password = None, None
    gmailrc_path = pathlib.Path("~/.gmailrc").expanduser().absolute()
    if gmailrc_path.exists() and not gmailrc_path.is_dir():
        with open(gmailrc_path, "r") as f:
            gmailrc = yaml.safe_load(f)
        username, password = gmailrc.get("username"), gmailrc.get("password")
    if args.username is not None:
        username = args.username
    if username is None:
        raise ValueError(f"must provide a username")
    if args.password:
        password = getpass.getpass(f"Password for {username}")
    if password is None:
        raise ValueError(f"must provide a password")
    if args.to is None:
        if "@" in username:
            recipient = username
        else:
            recipient = f"{username}@gmail.com"
    else:
        recipient = args.to
    send_email(username, password, recipient, args.subject, args.body)


if __name__ == "__main__":
    main(create_parser().parse_args())