Calendar 'Loading...' issue with iCloud

[nigel-daniels]

I have seen a problem when using an iCloud url with the calendar module that I thought I’d post in case anyone else runs into the issue.

Symptoms
The symptom is the calendar sticks with the ‘Loading…’ message but never loads. On the command line I saw the following error:

Ready to go! Please point your browser to: http://localhost:8080
Create new calendar fetcher for url: http://p02-calendarws.icloud.com/ca/subscribe/1/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx - Interval: 300000
Whoops! There was an uncaught exception...
[Error: Invalid UNTIL value: 20160730T115959]
MagicMirror will not quit, but it might be a good idea to check why this happened. Maybe no internet connection?
If you think this really is an issue, please open an issue on GitHub: https://github.com/MichMich/MagicMirror/issues

Cause
With Mitchs support the problem has been traced to the rrule library which handles recurring calendar events. There is an open issue on the library here:

https://github.com/jkbrzt/rrule/issues/145

It seems the library is strictly following RFC2445 detailing how UTC dates work, but it seems not every calendar provider is structuring the dates per RFC2445 when they are set to a local time.

I’ve added the problem I’m seeing to the issue 145. I hope that helps anyone else encountering the same issue.