A Tale about Time - LaravelLive India 2018

Timezones, DST, human readable diffs, standardised formats, intervals, getting the last Tuesday of next month… Dealing with timestamps seems easy, but there’s a lot to it. It’s very easy to do it wrong. Learn how to do this properly and you’ll never be chasing weird time related bugs anymore!

Transcript

1. A Tale about Time
   @hannesvdvreken
   @laravellivein
   

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2. Hi, my name is Hannes.
   

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3. !
   

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6. A Tale about Time
   

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7. 2018-03-17T10:15:00+05:30
   

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11. EST = UTC-05:00
    

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12. UTC+05:45
    

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13. UTC+05:30
    

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14. Helsinki
    Sunrise: 9:24 - 3:54
    Sunset: 15:13 - 22:50
    Quito
    Sunrise: 6:08 - 6:12
    Sunset: 18:16 - 18:19
    

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16. EST/EDT - March 12
    CET/CEST - March 24
    

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17. '
    

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18. (
    

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19. )
    

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20. Storing vs Expressing time
    

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21. 6:00PM vs 18:00
    

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23. 1521261900
    >1970-01-01T00:00:00+00:00
    

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24. 1521261900
    >1970-01-01T00:00:00+00:00
    <2038-01-19T03:14:07+00:00
    

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25. RFC3339:
    2018-03-17T10:15:00+05:30
    

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26. RFC3339 extended:
    2018-03-17T10:15:00.000+05:30
    

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27. Sortable:
    2018-03-17T05:45:00.000+00:00
    

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28. Calendars
    

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29. Weeks - 7 days
    

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30. Months
    Lunar vs Tropical
    

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31. Years
    Lunisolar vs Tropical
    

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32. 2018AD
    1500BC
    

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33. Leap years
    

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34. Leap years
    Leap seconds
    

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35. Time in PHP
    

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36. DateTimeInterface
    - DateTime (date, time, tz)
    - DateTimeImmutable
    

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37. $date = $date->setTimezone(‘Asia/Kolkata');
    

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38. $date = DateTimeImmutable::createFromMutable($mutable);
    

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39. Change in PHP 7.1: microseconds
    

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40. // Magic
    $date = new DateTimeImmutable(‘now’);
    $date = $date->modify(‘first day of next month’);
    

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41. “now + 5 hours”
    “first day of next month”
    "first weekday”
    …
    

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42. “2016-03-00” → “2016-02-29”
    “2018-06-31” → “2018-07-01”
    …
    

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43. “69-12-31” → “2069-12-31”
    “70-01-01” → “1970-01-01”
    …
    

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44. nesbot/carbon - Mutable
    cakephp/chronos - Immutable
    

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45. interface Clock
    {
    public function now(): DateTimeImmutable
    }
    

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46. The future
    

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47. E=mc²
    

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48. c ~ 299.000.000m/s
    

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51. Wrapping up
    

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52. Thanks for your time!
    @hannesvdvreken
    @laravellivein
    

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53. Time for questions.
    @hannesvdvreken
    @laravellivein
    

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