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Dirkjan Bussink
February 10, 2015
Programming
0
110
Time
A talk about how to handle time and timezones. Given at Twente.rb
Dirkjan Bussink
February 10, 2015
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Transcript
Time Dirkjan Bussink! @dbussink
Time is hard
None
None
None
None
None
Basics
None
Timezones
http://momentjs.com/
http://momentjs.com/
Storing
UTC
Why?
2014-10-26 02:34
A bit more! complicated
Group! by date
None
Who’s date?
http://pellepim.bitbucket.org/jstz/
None
None
Calculations
None
Perspective
None
UTC loses data
UTC + offset
2014-08-19 16:12:50 +0200
Time as a feature
Calendars
None
None
DST
amsterdam = ActiveSupport::TimeZone["Europe/Amsterdam"] time = amsterdam.parse("2014-08-19 17:15") => Tue, 19
Aug 2014 17:15:00 CEST +02:00
sydney = ActiveSupport::TimeZone[“Australia/Sydney"] ! time => Tue, 19 Aug 2014
17:15:00 CEST +02:00 time.in_time_zone(sydney) => Wed, 20 Aug 2014 01:15:00 EST +10:00
later = time + 6.months => Thu, 19 Feb 2015
17:15:00 CET +01:00 ! later.in_time_zone(sydney) => Fri, 20 Feb 2015 03:15:00 EST +11:00
Our recurring meeting! just moved 2 hours!
UTC + offset! isn’t good enough
Time & time zone Europe/Amsterdam Tue, 19 Aug 2014 17:15:00
CEST +02:00
Time tracking
Check in & check out
125% 22:00 00:00 150% Break 150% 01:00 01:30 06:00
DST
125% 150% Break 150% 01:30 02:00 02:59 02:00 03:00
9 hours from 22:00 until 06:00
Very specific! storage format
Day!! ! ! ! ! ! ! 2014-10-26! Start!! !
! ! ! ! 79200!! ! ! End!! ! ! ! ! ! ! 108000! Duration!! ! 32400
Take away
Start with UTC
Be careful! with timezones
Make conscious! decisions