Time

A talk about how to handle time and timezones. Given at Twente.rb

Transcript

1. Time Dirkjan Bussink! @dbussink
2. Time is hard
8. Basics
10. Timezones
11. http://momentjs.com/
12. http://momentjs.com/
13. Storing
14. UTC
15. Why?
16. 2014-10-26 02:34
17. A bit more! complicated
18. Group! by date
20. Who’s date?
21. http://pellepim.bitbucket.org/jstz/
24. Calculations
26. Perspective
28. UTC loses data
29. UTC + offset
30. 2014-08-19 16:12:50 +0200
31. Time as a feature
32. Calendars
35. DST
36. amsterdam = ActiveSupport::TimeZone["Europe/Amsterdam"] time = amsterdam.parse("2014-08-19 17:15") => Tue, 19 Aug 2014 17:15:00 CEST +02:00
37. 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
38. 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
39. Our recurring meeting! just moved 2 hours!
40. UTC + offset! isn’t good enough
41. Time & time zone Europe/Amsterdam Tue, 19 Aug 2014 17:15:00 CEST +02:00
42. Time tracking
43. Check in & check out
44. 125% 22:00 00:00 150% Break 150% 01:00 01:30 06:00
45. DST
46. 125% 150% Break 150% 01:30 02:00 02:59 02:00 03:00
47. 9 hours from 22:00 until 06:00
48. Very specific! storage format
49. Day!! ! ! ! ! ! ! 2014-10-26! Start!! ! ! ! ! ! 79200!! ! ! End!! ! ! ! ! ! ! 108000! Duration!! ! 32400
50. Take away
51. Start with UTC
52. Be careful! with timezones
53. Make conscious! decisions