exec-notify/execNotifyDir/mail.py

import sys
import datetime
import smtplib, ssl
import socket

from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

from execNotifyDir import config


def sendMailOrWriteToFile(SUBJECT: str, BODY: str):
    try:
        sendMail(SUBJECT=SUBJECT, BODY=BODY)
    except Exception as e:
        print("Error: Could not send mail! Writing to file instead ...", file=sys.stderr)
        print(e, file=sys.stderr)

        # Instead, try to save the mail so that the user can read
        # it later when connected to this computer
        saveMail(SUBJECT=SUBJECT, BODY=BODY)


def sendMail(SUBJECT: str, BODY: str):
    """
    :throws Exception: if mail could not be sent
    """

    FROM = config.getFrom()
    TO = config.getTo()
    password = config.getPassword()

    # Create a secure SSL context
    context = ssl.create_default_context()

    host, port = config.getHostAndPort()
    with smtplib.SMTP_SSL(host=host, port=port, context=context) as server:
        server.login(FROM, password)
        message = MIMEMultipart()
        message["Subject"] = SUBJECT
        message["From"] = FROM
        message["To"] = TO
        message["Bcc"] = TO  # Recommended for mass emails
        # Turn plain/html message_body into plain/html MIMEText objects
        message.attach(MIMEText(BODY, "plain"))

        server.sendmail(FROM, TO, message.as_string())


def saveMail(SUBJECT: str, BODY: str):
    """
    This method does NOT throw exceptions
    """

    time = datetime.datetime.now()
    timeStr = time.strftime('%Y%m%d_%H%M%S')

    DATE = '=' * 20 + '\n=== date ===\n' + timeStr + '\n'
    SUBJECT = '=== subject ===\n' + SUBJECT + '\n'

    try:
        # append to file; create file if not existent
        with open(config.getErrorFile(), "a") as f:
            f.write(DATE)
            f.write(SUBJECT)
            f.write(BODY)
    except Exception as e:
        print('Error: Could not write to file!', file=sys.stderr)
        print(e, file=sys.stderr)


def prevMailNotSent():
    return config.getErrorFile().exists()


def informAboutOldMail():
    """
    Try to inform user via mail about previous error(s) that could not be sent to him before.
    Maybe this time sending of an email works ;)
    """

    SUBJECT = '{} | Some mails not sent!'.format(socket.gethostname())
    BODY = 'Please check the file {} for mails which could previously not be sent to you!\n' \
           'Note: You may delete the file after reading it ;)' \
        .format(config.getErrorFile())
    sendMail(SUBJECT=SUBJECT, BODY=BODY)