Different timezones and UTC in database

Hi, you must do couple of things to correctly display time in your app:

1. setup timezone of the server/application
Set this line to correct value by the geolocation of the server. If your server is in Frankfurt for example, set it to Europe/Berlin. If you are the administrator of the server, install/setup NTP daemon too, so the server clocks are always at correct value.

2. allow user to set their timezone
you must provide user with some sort of timezone setup. Screen like this:

You must create this list of all possible timezones (use that wiki page link above).

3. store all date-time events/data as timestamp
Timestamp is best when dealing with timezones, because timestamp is timezone independent. You can convert timestamp into timezone time with code below.

4. display date-time event/date in users' timezone

$userTimezone = 'Asia/Ashgabat';  // get this from DB, step 2
$postCreatedAt = 1495971234;      // timestamp of date-time event you want to display, step 3

$datetimeObj = new Nette\Utils\DateTime();
$datetimeObj->setTimestamp($postCreatedAt);
$datetimeObj->setTimezone(new DateTimeZone($userTimezone));

echo $datetimeObj->format('Y-m-d H:i:sP') . "\n";
// 2017-05-28 16:33:54+05:00

Last edited by srigi (2017-05-28 13:47)

2. yes, users must setup their tz by themselfs. There is no timezone data in the request. However, you can use IP address to geolocate user request, usage.
3. ok
4. don't forget to set timezone of the datetime object to the users' tz.

Last edited by srigi (2017-05-28 15:45)