I'm trying to compare a start date of an event resource I have with the now date. All dates are being stored as UTC and then the timezone is set according to the user's timezone.
But when I compare the dates the difference is always the same regardless of the timezone I set. It's always being evaluated as UTC. So for instance when I set
$now = Carbon::now()->tz($profileTimezone);
And then try to compare it with another date
$difference = $now->diffInHours($event->starts_at));
It's always returning the same difference object with the same values regardless of the timezone I set for now. Shouldn't the difference in hours, for example, change when now is in a different timezone?
When running the tz method it will convert the datetime object to that timezone. Meaning if you change now to a timezone which is 1 hour behind from the current timezone, it will subtract that hour from the time.
What you are looking for is the method shiftTimezone, that one will change the timezone without changing the time also.
Carbon::now();
// 2019-07-29 12:53:29.575769 UTC (+00:00)
Carbon::now()->shiftTimezone('Asia/Phnom_Penh');
// 2019-07-29 12:53:29.572207 Asia/Phnom_Penh (+07:00)
Carbon::now()->tz('Asia/Phnom_Penh');
// 2019-07-29 19:53:29.575776 Asia/Phnom_Penh (+07:00)
Related
I'm struggling with the Carbon::now(), I'm specifying the desired timezone in the now function and it is not giving the date time based on the given timezone. It always using the UTC timezone that's specified in the laravel.
Carbon::now() // giving me date time of UTC timezone
Carbon::now('Asia/Karachi') // still giving me the date time of UTC timezone
var_dump(Carbon::now('Asia/Karachi')) // I'm able to see the correct date time based on the timezone.
So when I use the var_dump() I'm getting the correct date time based on the give timezone. Can anyone explain why it is nog returning the correct timezone from the Carbon::now('Asia/Karachi')? but dumping the instance showing the correct datetime.
I've also tried the php artisan cache:clear as well as php artisan config:clear
In config/app.php file change UTC to your desired timezone. It will change app timezone globally.
Eg:
'timezone' => 'Asia/Dhaka',
It always using the UTC timezone
Where? If you're talking about a JSON output, it's expected, date is formatted with ISO-8601 string and a trailing Z meaning Zulu = GMT timezone. The browser or client reading this JSON will have no issue to reconvert it then to any local date time using the user device timezone.
But at anytime if you dump explicitly this instance to a string using any format, the specified timezone will be used:
Carbon::now('Asia/Karachi')->format('Y-m-d H:i:s.u p')
(here using p or e you will see explicitly the timezone in the string.
I'm using Carbon inside of my Laravel API project, when trying to set the timezone and get a datetime back in the user's timezone, I'm for some reason getting a UTC value back, what am I doing wrong?
// $user->timezone will give me "America/Curacao" or whatever their time zone is
$curr = Carbon::now()->setTimezone($user->timezone)
But when I echo out the contents of $curr, I'm getting a UTC time of:
2021-04-05T11:58:35.186750Z
What am I missing?
You get the ISO-8601 string with is the standard format for dates in JSON. But the object is correctly in America/Curacao timezone. If you want to pass it to a Date object in the browser, you don't need the timezone and can just pass this string as is.
If you want to format the date to be seen by the user, then just pick the format after setting the timezone:
$curr = Carbon::now()->setTimezone($user->timezone)->format('Y-m-d H:i:s')
Or whatever format would be relevant for you.
And you should keep 'timezone' => 'UTC' in your app settings as your users will likely have any various timezone, and UTC is the more agnostic to use to save them back-end side.
I am developing a laravel application which stores GMT time in database accross the world.
Now I want user to see time in his local timezone but for this I must aware of user's local timezone which I don't.
I have user's country ISO code and using DateTimeZone::listIdentifiers method I can get the timezone but it returns array of timezones for some countries.
So is there a method or way through which I can get offset in hours between GMT +00:00 and user's local GMT time?
You need to make some request passing the timezone from client/browser to your server to get an accurate timezone.
Many countries have multiple timezones, Russia, USA, just to mention some. So country code is not enough.
Then, don't use offset, use named timezone as many timezones also have multiple offset due to daylight saving. Europe/Paris can be GMT+1 or GMT+2 and so current offset between GMT+0 now != current offset for your given timestamp.
When you have the precise city name of the timezone, then it's really simple to use it before formatting a Carbon date:
Carbon::createFromTimestamp($utcTimestamp)->tz('America/New_York')
I saved a record in 17:16:15, I run a job which gets the ModifiedOn field of my record and I got- 15:16:15, my GMT is +2, I want to know how to fix that gap that my result will turn out like it should be - 17:16:15. I can't select it from DB I need a solution in server side (c# I mean) what can U do in that case?
DateTimes are always saved in UTC in the database. *
You need to dynamically convert from UTC into your local time zone. In C#, you can do this with the .ToLocalTime() method as long as your code is running in the correct time zone. You can also find your local time in the FormattedValues collection of the response, which uses your Dynamics timezone user settings . But the raw datetime value in the database will always be in UTC.
* The only exception to this is if the DateTime field is set to “TimeZone Independent” in the attribute type settings. But be careful: once you set this option you can’t change it for that field again.
I am currently storing events of some entities in UTC time but I am not sure if I should do that in this case. Imagine there's an event at 10pm local time (-4h UTC) and a mobile App fetches "todays events". This could e.g. look like this:
App sends request to fetch all clubs in the near location
After receiving all clubs it sends a request to get all events for today. It therefore sends the local time Sun. 10pm to the server.
The server would convert the local time of the mobile device to UTC Mon. 1am and fetch all events from Monday. But of course that was not what I wanted.
Fetching all events from the clubs and convert them to their local time using their local time offset information is not really a great solution.
So wouldn't it be better to just store all events in local time? In that case the mobile App would send its local time to the server which would be able to query all events from the clubs in local time as well.
This sounds much simpler to me but I am not sure if I overlook something.
So what would I do in this case?
Yes, storing everything in UTC is probably the best solution.
You don't say how you are "storing" the dates/times, but if you are using Dates or Joda equivalents, then you should know that their underlying representation is effectively in UTC (they represent a moment in time as an offset in milliseconds since the "Epoch", which is Midnight, Jan 1, 1970 UTC). These dates only have a timezone when you format them as Strings.
Most databases do something similar (store the date in a common timezone, usually UTC). The major exception that I've found is the generally available date-time related column types in MS SqlServer which by default store everything in the local timezone of the server.
Also be aware that if you use SQLite, and you store a date/time by passing a String in SQL that contains a timezone, SQLite will store it without warning, but will ignore the timezone and assume that the timezone is UTC, giving you a result other than what you might expect.
For more on this, see my (old) blog post at http://greybeardedgeek.net/2012/11/24/java-dates/
The other answer is correct. Some more thoughts here.
A time zone is more than the offset from UTC mentioned in the Question. A time zone is also the set of past, present, and future rules for anomalies such as Daylight Saving Time. You should refer to a time zone by its proper name, continent plus Slash plus city or region. Never use the 3-4 letter codes such as EST or IST.
To search for events in the user's "today", you must know the user’s time zone. For example, a new day dawns earlier in Paris than in Montréal. After the stroke of midnight in Paris we still have a few hours of “yesterday” left to go in Montréal.
While you can make a guess as to the user’s time zone, the most reliable way is to ask the user.
DateTimeZone zone = DateTimeZone.forID( "America/Montreal" );
DateTimeZone now = DateTimeZone.now( zone );
DateTime today = now.withTimeAtStartOfDay();
DateTime tomorrow = today.plusDays( 1 );
// Search for events that start >= today AND that start < tomorrow.
To search Joda-Time objects, use the Comparator built into DateTime. That comparator works across objects of various time zones.
To query a database, convert that pair of DateTime objects into java.sql.Timestamp objects. You do that by extracting and passing the count of milliseconds since the epoch of 1970 in UTC.
long m = today.getMillis();
java.sql.Timestamp tsToday = new java.sql.Timestamp( m );