Check an email address in python

pyemailping.py

#!/usr/bin/python

import smtplib
import dns.resolver


def get_mx_records(domain):
    try:
        records = dns.resolver.query(domain, "MX")
        preferred = sorted(records, key=lambda r: r.preference)
        return [r.exchange.to_text(omit_final_dot=True) for r in preferred]
    except dns.resolver.NXDOMAIN:
        return []


def get_domain_part(email_address):
    return receiver[receiver.index("@") + 1:]


def send_smtp_command(s, command, **kwargs):
    status, response = s.docmd(command)
    expected = kwargs.get("expected")

    if expected and status != expected:
        msg = "Expected status {0}, received {1} {2}".format(
            expected, status, response)
        raise AssertionError(msg)

    return status


def ping_exchange(exchange, receiver, sender):
    s = smtplib.SMTP(exchange, 25)
    send_smtp_command(s, "HELO", expected=250)
    send_smtp_command(s, "MAIL FROM: <{}>".format(sender), expected=250)
    status = send_smtp_command(s, "RCPT TO: <{}>".format(receiver))
    send_smtp_command(s, "QUIT")

    return status == 250


def ping(receiver, sender):
    if "@" not in receiver:
        return False

    domain = get_domain_part(receiver)
    exchanges = get_mx_records(domain)

    if exchanges:
        return ping_exchange(exchanges[0], receiver, sender)
    else:
        return False


if __name__ == "__main__":
    from sys import argv
    receiver, sender = argv[1], argv[2]
    success = ping(receiver, sender)

    if success:
        print("Successfully contacted %s from %s" % (receiver, sender))
    else:
        print("Could not contact %s from %s" % (receiver, sender))

requirements.txt

dnspython==1.12.0