fahrplan icon indicating copy to clipboard operation
fahrplan copied to clipboard
verified publisher icon smurfy

Fix some daylight saving time issues by using UTC.

Open benzea opened this issue 10 years ago • 7 comments

Ok, this seems to work now. I have not actually done any search during daylight saving time change, as I cannot properly test it (cannot select the date in the GUI). The one thing I am not entirely sure about is what happens if the connection itself crosses the daylight saving time change. It is definitely an improvement to the current situation.

benzea avatar May 03 '15 19:05 benzea

sorry, i did not forgot this PR, i just want to make sure that this problem is not with the other backends as-well.

smurfy avatar May 19 '15 19:05 smurfy

This PR breaks the time on the details page. Even for today.

smurfy avatar May 20 '15 19:05 smurfy

I am a bit surprised, thought I had that tested ...

Hm, we could just change it to use UTC and a fixed base date for times and leave the addSecs part as is. That should at least work, but I don't understand how it might be failing.

benzea avatar May 20 '15 20:05 benzea

Wait, are the datetime objects passed around somewhere, and then a timezone conversion happens in the background? When I hit getJourneyDetails in the fahrplan2 UI, then the times are correct, but obviously they are displayed as UTC (as that is what they are with the patch, even thought that is wrong)

benzea avatar May 20 '15 20:05 benzea

With correct I mean, if you assume that the time is really local time and not UTC, then it is correct.

benzea avatar May 20 '15 20:05 benzea

I have to take a look, why the date is displayed as is, in the journey overview, but not in the details.

As far as i remember the date difference is about 2 hours more than the "correct" time. On 25th of october the 00:xx trains in my tests even will be displayed as 03:xx on details.

smurfy avatar May 21 '15 06:05 smurfy

Oh, two hours sounds like the time zone, but 03:XX in oktober sounds weird though (haven't thought it fully through though). Can I properly do a search in october with the "fahrplan2" desktop UI?

The trouble is that we have two timezones in the process as it is impossible to use the phones time zone to store the data:

  • current time zone of the phone
  • UTC (as the patch does) or correct timezone for each backend

I do think that the user will always want to see the local time for the backend. So just using UTC and hiding the fact works, but using the correct local time would also be good (the advantage is that you could generate correct calender entries then).

Then we would need to:

  • Store timezone for each backend
  • correctly convert the hours/minutes to this timezone (not sure how to best do this right now)
  • ensure dates/times are not converted to phones local time for display

benzea avatar May 21 '15 08:05 benzea