Radicale Email Reminder ======================= A standalone script designed to run repeatedly against a Radicale collection to send email reminders that match VALARMs nested in ICS/iCalendar files. The objective is to simply send emails along with any alert/alarm that is specified in any calendar event or to-do item. Very few open source CalDAV servers support such email notifications out-of-the-box. This project effectively allows any iCalendar VALARM to double as an email alert. This script supports *all* RFC 5545 VALARM use cases, and properly implements email reminders for both repeating and expiring events. Requirements ------------ - Radicale <https://radicale.org/> - icalendar <https://pypi.org/project/icalendar/> (should have already installed alongside Radicale) - Cron or Schtasks Setup ----- There really isn't much to lay out. When setting up Cron or Schtasks, simply specify the proper Python command. For Cron: * * * * * radicale python /var/lib/radicale/radicale_email_reminder.py /var/lib/radicale/collections/collection-root 1 ::1 25 'Radicale Reminder <admin@smith.net>' > /dev/null This will run "radicale_email_reminder.py" (which happens to be located in "/var/lib/radicale/") once a minute. Read further for information about the script's arguments. It might also be cleaner to move that bulky command into its own shell script where you can break lines and make other improvements. CLI Usage --------- python radicale_email_reminder.py <directory> <minutes ahead> <mail server host> <mail server port> <from address> <directory> Ideally this should be the path to the root Radicale collection. This script is actually agnostic to the CalDAV server itself. The given directory must simply contain the ICS/iCal files that are managed by any server. <minutes ahead> When the script runs, it must calculate the window in which VALARMs must fall so that their emails are sent. The window always starts at the zeroth second of the minute it runs. E.g. if the script starts at 2019-03-06T09:00:32.856Z (bear with me), and <minutes ahead> is "2", then it will send emails for all VALARMs that fall exactly *at* or *later* than 2019-03-06T09:00:00Z, and exactly *earlier* than 2019-03-06T09:02:00Z. VALARMs *at* exactly 2019-03-06T09:02:00Z will *not* be sent. This is to eliminate the possibility of duplicate emails when the script runs again at say 2019-03-06T09:02:15.283Z, in which case the window will be greater than or equal to 2019-03-06T09:02:00Z and strictly less than 2019-03-06T09:04:00Z. So yeah, every 2 minutes without repetition. <mail server host> So in order for emails to go out at all, an SMTP server must be specified. This script is meant to be as simple as possible, so chances are you will be deploying this with some cookie-cutter mail setup over a local network/host. - SMTPS and other historical protocols are *not* supported. - Authentication of any kind is *not* supported. - STARTTLS *is* supported it's easy. <mail server port> Port for the aforementioned host. As this script does not support authentication, this will likely be "25". <from address> The sender of the notification emails. Should follow the standard <https://tools.ietf.org/html/rfc5322#section-3.4>. E.g.: Radicale Reminder <admin@smith.net> In other words, should simply follow all the best practices for outgoing email. Setting an Email Reminder ------------------------- By now you're wondering where to specify the recipients of email reminders. In technical terms, a special syntax must be entered at the *top* of the "DESCRIPTION" in the VEVENT or VTODO closures in an iCal file, like so: DESCRIPTION:Notify:\nsmith@smith.net\nSomeone <someone@mymail.com>\n-\n\nTh is is a note/description/detail of the event. From a UI like InfCloud, it will be the "Note" section when creating a new calendar event or to-do item. The example above was generated by the following "Note": Notify: smith@smith.net Someone <someone@mymail.com> - This is a note/description/detail of the event. Notice the "Notify:" (yes, with the colon), followed by a new-line, followed by new-line separated email addresses, followed by a final new-line, then a dash. An email will be sent for this event containing the description "This is a note/description/detail of the event." and omitting the notify section. Don't forget to also set the actual alerts/reminders. Specifying a notify section without adding any actual VALARMs will obviously do nothing. In InfCloud they are each called "Alert". Contributing ------------ Please communicate changes over this project's GitLab/GitHub pages. Bear in mind that this is not and never will be a large-scale project, and the GitLab/GitHub pages are merely mirrors of a separate "official" repository. Any accepted changes will get due authorship and credit. https://gitlab.com/nzeid/radicale-email-reminder https://github.com/nzeid/radicale-email-reminder License ------- Copyright (c) 2019 Nader G. Zeid This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/gpl.html>. Acknowledgments --------------- Special thanks to the awesome work by the Radicale <https://radicale.org/> and icalendar <https://pypi.org/project/icalendar/> teams. And a thanks-as-always to the Python Software Foundation.
nzeid/radicale-email-reminder
A standalone script for Radicale to send email reminders matching VALARMs in ICS/iCalendar files.
PythonGPL-3.0