It's pretty easy to convert a given GMT date into local time if you're given the timezone identifier from this list in PHP: http://www.php.net/manual/en/timezones.php
For example, you can do this (where $fromTimeZone is just 'GMT', $toTimeZone is just one of the constants from that list (i.e. 'America/Chicago'), and $datetime is the GMT date):
public static function convertToTimezone($datetime, $fromTimeZone, $toTimeZone, $format = 'Y-m-d H:i')
{
// Construct a new DateTime object from the given time, set in the original timezone
$convertedDateTime = new DateTime($datetime, timezone_open($fromTimeZone));
// Convert the published date to the new timezone
$convertedDateTime->setTimezone(timezone_open($toTimeZone));
// Return the udpated date in the format given
return $convertedDateTime->format($format);
}
However, I'm having issue converting the same GMT date to the local time if just given the timezone offset. For instance, instead of being given 'America/Chicago', I'm given -0500 (which is the equivalent offset for that timezone).
I've tried things such as the following (where $datetime is my GMT date and $toTimeZone is the offset (-0500 in this case)):
date($format, strtotime($datetime . ' ' . $toTimeZone))
I know all the date() sort of functions are based on the servers's timezone. I just can't seem to get it to ignore that and use a timezone offset that is given explicitly.
You can convert a specific offset to a DateTimeZone:
$offset = '-0500';
$isDST = 1; // Daylight Saving 1 - on, 0 - off
$timezoneName = timezone_name_from_abbr('', intval($offset, 10) * 36, $isDST);
$timezone = new DateTimeZone($timezoneName);
Then you can use it in a DateTime constructor, e.g.
$datetime = new DateTime('2012-04-21 01:13:30', $timezone);
or with the setter:
$datetime->setTimezone($timezone);
In the latter case, if $datetime was constructed with a different timezone, the date/time will be converted to specified timezone.
Related
I know \DateTimeZone::listIdentifiers() returns all timezone identifiers, but how can I retrieve their actual offset from UTC?
There is method getoffset
<?php
// Create two timezone objects, one for Taipei (Taiwan) and one for
// Tokyo (Japan)
$dateTimeZoneTaipei = new DateTimeZone("Asia/Taipei");
$dateTimeZoneJapan = new DateTimeZone("Asia/Tokyo");
// Create two DateTime objects that will contain the same Unix timestamp, but
// have different timezones attached to them.
$dateTimeTaipei = new DateTime("now", $dateTimeZoneTaipei);
$dateTimeJapan = new DateTime("now", $dateTimeZoneJapan);
// Calculate the GMT offset for the date/time contained in the $dateTimeTaipei
// object, but using the timezone rules as defined for Tokyo
// ($dateTimeZoneJapan).
$timeOffset = $dateTimeZoneJapan->getOffset($dateTimeTaipei);
// Should show int(32400) (for dates after Sat Sep 8 01:00:00 1951 JST).
var_dump($timeOffset);
?>
You can build an associative array mapping timezones and their offset using the getOffset method of DateTime instance.
getOffset returns the difference in seconds of a date evaluated in the time zone of the provided datetime argument (in our example, this is the current time in utc), and the same datetime as evaluated in the local time zone.
$utcNow = new DateTime('now', (new DateTimeZone('UTC')));
$identOffset = array_map(
function ($ident) use ($utcNow) {
$localTimeZone = new DateTimeZone($ident);
$offset = $localTimeZone->getOffset($utcNow);
return [$ident => $offset] ;
},
DateTimeZone::listIdentifiers()
);
$identOffset = array_merge(...$identOffset);
var_dump($identOffset);
If you are using https://carbon.nesbot.com/
// You will get timezone offset as string
Carbon::now('Asia/Kathmandu')->getOffsetString(); // +05:45
For example
strtotime("2018-12-06T09:04:55");
strtotime("2021-07-09T14:09:47.529751-04:00");
I read in the php manual that ISO dates should be avoided when using strtotime, why ?
Should I extract date time from the string before using strtotime.
strtotime() will convert a string WITHOUT a timezone indication as if the string is a time in the default timezone ( date_default_timezone_set() ). So converting a UTC time like '2018-12-06T09:04:55' with strtotime() actually yields a wrong result. In this case use:
<?php
function UTCdatestringToTime($utcdatestring)
{
$tz = date_default_timezone_get();
date_default_timezone_set('UTC');
$result = strtotime($utcdatestring);
date_default_timezone_set($tz);
return $result;
}
?>
If the date string contains a time zone, strtotime also takes this into account.
$strDate = "2018-12-06T09:04:55 UTC";
$ts = strtotime($strDate); // int(1544087095)
If the time zone is missing in the date string, the default time zone is used. My Timezone is "Europe/Berlin".
$strDate = "2018-12-06T09:04:55";
$ts = strtotime($strDate); // int(1544083495)
As a result, we get a different timestamp.
If I want to convert a date string from another time zone into a time stamp, then the best solution is to do it with the DateTime object. There I can enter the correct time zone in the 2nd parameter when creating the object.
$strDate = "2018-12-06T09:04:55";
$dt = new DateTime($strDate, new DateTimeZone('UTC'));
$ts = $dt->getTimeStamp(); // int(1544087095)
Important: If the date string contains a valid time zone, this has priority over the 2nd parameter.
$strDate = "2018-12-06T09:04:55 UTC";
$dt = new DateTime($strDate, new DateTimeZone('Europe/Berlin'));
/*
DateTime::__set_state(array(
'date' => "2018-12-06 09:04:55.000000",
'timezone_type' => 3,
'timezone' => "UTC",
))
*/
The DateTimeZone ('Europe/Berlin') is ignored here.
Since strtotime also accepts a time zone in the date string, the time zone can also be added with a string concatenation.
$strDate = "2018-12-06T09:04:55";
$ts = strtotime($strDate." UTC"); //int(1544087095)
The UTCdatestringToTime function does the same. However, it is not nice to temporarily change the default time zone in the PHP script.
I am attempting to retrieve a date that is not in GMT and convert it to GMT. To do this, I am creating two time zones (one GMT and one non-GMT) and attempting to get the offset between them. However, the offset is only correct in one direction. For this specific example, I am trying to compare GMT +4 to GMT. I expect to get 4hrs (14400 seconds) when I compare the the GMT timezone to the GMT+4 timezone, and -4hrs (-14400 seconds) when I compare the GMT+4 timezone to GMT. However, when comparing the later I'm getting 0... Here is what I have
$default_timezone = new DateTimeZone(drupal_get_user_timezone());
$default_reg_date = new DateTime($reg_date_string, $default_timezone);
$gmt_timezone = new DateTimeZone('UTC');
$gmt_reg_date = new DateTime($reg_date_string, $gmt_timezone);
// Returns as 14400
$default_gmt_offset = $default_timezone->getOffset($gmt_reg_date);
// Returns as 0
$gmt_default_offset = $gmt_timezone->getOffset($default_reg_date);
Why can't I get the right number, what am I doing wrong? Does retrieving the offset only work one way?
Note: in this specific example, drupal_get_user_timezone() is returning GMT+4
From the PHP documentation :
This function returns the offset to GMT for the date/time specified in the datetime parameter. The GMT offset is calculated with the timezone information contained in the DateTimeZone object being used.
The function works with 2 logics steps :
Convert the date into the timezone on which the function is applied
Get the offset from GMT
So calling this function on new DateTimeZone('UTC') will always returns 0
If you want to convert a date into UTC, you can use the setTimeZone function :
$date_string = '2020-05-01 09:11:00' ;
$date = new DateTime($date_string, new DateTimeZone('Europe/Brussels'));
echo $date->format('c') ; // 2020-05-01T09:11:00+02:00
$date->setTimeZone(new DateTimeZone('UTC'));
echo $date->format('c') ; // 2020-05-01T07:11:00+00:00
Suppose I have an offset like this:
$secOffset = -28800
I need it to convert in a format that is usable with MYSQL function convert_tz()
If I use gmdate("h:i", secOffset) I got 16:00 that is almost correct but It miss the minus - (that is quite important)
Alternative approach:
Suppose I have a time string America/Los_Angeles and I want to convert in a offset useful for MYSQL function convert_tz()
The final expected output is the offset from GMT so given a timezone.
For ex, having a timezone like America/Los_Angeles, the output should be:
−08:00
I'm on Magento/Zend so if any available function is on Zend I can accept answer based on it.
You should use the DateTimeZone and DateInterval classes for this:
$tzid = 'America/Los_Angeles';
$tz = new DateTimeZone($tzid);
$date = new DateTime('now', $tz);
// create a new date offset by the timezone offset
// gets the interval as hours & minutes
$offset = $tz->getOffset($date) . ' seconds';
$dateOffset = clone $date;
$dateOffset->sub(DateInterval::createFromDateString($offset));
$interval = $dateOffset->diff($date);
$formatted = $interval->format('%R%H:%I');
This is a little convoluted, as you first get the timezone offset in seconds, and then use DateTime to help convert that interval into hours/mins.
I need to display user's activities date as per the current time zone.
My approach -
Getting a timezone offset from javascript and storing it to the user's profile table.
When user logged in, getting time zone offset.
current date is working fine with time zone offset-
$offsetDiff = $_SESSION['TimeZone']*60;
$UserDateTime = time() + $offsetDiff;
$currentDate = date('Y-m-d',$UserDateTime);
Dateo other then today is not working properly -
$offsetDiff = $_SESSION['TimeZone']*60;
$UserDateTime = '2014-02-10 08:58:00'; + $offsetDiff;
$monthUser = date('Y-m-d',$UserDateTime);
Can anybody please let me know how can i show correct date according to time zone offset?
You can convert a specific offset to a DateTimeZone:
$offset = '-0500';
$isDST = 1; // Daylight Saving 1 - on, 0 - off
$timezoneName = timezone_name_from_abbr('', intval($offset, 10) * 36, $isDST);
$timezone = new DateTimeZone($timezoneName);
Then you can use it in a DateTime constructor, e.g.
$datetime = new DateTime('2012-04-21 01:13:30', $timezone);
or with the setter:
$datetime->setTimezone($timezone);
In the latter case, if $datetime was constructed with a different timezone, the date/time will be converted to specified timezone.