If you have some calendar(s) on a calendar service that supports CalDAV (e.g. Fastmail, Google Calendar) then this is a Python script that can create a copy of those calendar(s) with all the details redacted, and save it back to the same service. It's like the free/busy sharing feature. Except, I found that sometimes the implementation of that feature does not work well, e.g. recurring events are unrolled into every individual repetition of the event, bloating the size of the shared calendar massively. The implementation in this script is very simple, it just combines all the events from the selected calendar(s) and deletes/redacts the properties that have identifying information, but leaves other fields such as repeating rules the same.
Clone the repo and create .env file in it
CALDAV_URL=
CALDAV_USERNAME=
CALDAV_PASSWORD=
CALDAV_COLLECTIONS=
CALDAV_REDACTED=
The URL, username, and password are your CalDAV connection details.
- Fastmail is straightforward: documentation
- Google has something with OAuth2...? You can try figuring it out if you want.
The last two parameters are your calendar/collection IDs to operate on. First one is a list of the calendars to combine (comma-separated list), second one is the calendar to write the redacted events to. You identify calendars using their CalDAV IDs, not using their display names. On Fastmail for example, these are UUIDs and you can find them by clicking "export" next to a calendar in the settings and noting the UUID in the URL.
Install dependencies with Poetry or
equivalent following the versions in pyproject.toml, poetry.lock.
Execute
poetry run python -m calendar_redacter
on a cron job with the desired frequency. Your events should show up automatically in the target calendar you specified.
The redaction isn't very smart as this is mostly a proof of concept. Check the source code to see how I did it. Basically I just remove specific ICS fields that I saw contained unnecessary information. There could be some I missed that did not turn up in sample data.
Event and calendar IDs are transformed by unsalted SHA1 since they sometimes contain email addresses and other information in them. You might still be able to reverse the hash if you have a good guess of what the original values were.
I wrote this documentation in 5 minutes. If something is unclear just ask and I will add more details to cover the issue.