Re:UTC Is Enough for Everyone, Right?
by cryptonector on Tuesday May 29, 2018 @07:22PM
(#17183613)
But users want wall clock time. That you stored 2018-05-26T13:45:21+02:00 is irrelevant. The user wants that time to change if the original timezone's definition changes.
So you really need to store {datetime, timezone_name}.
It gets tricky when you don't know the timezone... For example, you're on a plane with your devices in airplane mode and no wifi connectivity, and you want to create a calendar event in destination time... The UI had better let you specify a TZ, and you'll have to know what it is. Whereas if you want until you land you can just let your devices figure out what TZ you're in and spare you the bother of thinking about it. That's an unlikely edge case, but the UI should really let you input a TZ if you want to. Perhaps the UI should insist on you entering a TZ if you're in airplane mode.
So you really need to store {datetime, timezone_name}.
It gets tricky when you don't know the timezone... For example, you're on a plane with your devices in airplane mode and no wifi connectivity, and you want to create a calendar event in destination time... The UI had better let you specify a TZ, and you'll have to know what it is. Whereas if you want until you land you can just let your devices figure out what TZ you're in and spare you the bother of thinking about it. That's an unlikely edge case, but the UI should really let you input a TZ if you want to. Perhaps the UI should insist on you entering a TZ if you're in airplane mode.