Please note that on Debian/Ubuntu this function will return the system timezone defined in /etc/localtime if date.timezone is not defined, even with PHP 5.4+
See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=673763#10
(PHP 5 >= 5.1.0, PHP 7, PHP 8)
date_default_timezone_get — Récupère le décalage horaire par défaut utilisé par toutes les fonctions date/heure d'un script
Cette fonction retourne le décalage horaire en suivant l'ordre de préférences suivant :
Lecture du décalage horaire défini en utilisant la fonction date_default_timezone_set() (si elle existe)
Lecture de la valeur de l'option de configuration date.timezone (si elle est définie)
Si tout ce qui précède échoue, date_default_timezone_get()
retournera le décalage horaire par défaut de UTC
.
Cette fonction ne contient aucun paramètre.
Retourne une chaîne de caractères.
Exemple #1 Récupération du décalage horaire par défaut
<?php
date_default_timezone_set('Europe/London');
if (date_default_timezone_get()) {
echo 'date_default_timezone_set : ' . date_default_timezone_get() . '<br />';
}
if (ini_get('date.timezone')) {
echo 'date.timezone : ' . ini_get('date.timezone');
}
?>
Résultat de l'exemple ci-dessus est similaire à :
date_default_timezone_set : Europe/London date.timezone : Europe/London
Exemple #2 Récupération de l'abréviation d'un décalage horaire
<?php
date_default_timezone_set('America/Los_Angeles');
echo date_default_timezone_get() . ' => ' . date('e') . ' => ' . date('T');
?>
L'exemple ci-dessus va afficher :
America/Los_Angeles => America/Los_Angeles => PST
Please note that on Debian/Ubuntu this function will return the system timezone defined in /etc/localtime if date.timezone is not defined, even with PHP 5.4+
See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=673763#10
In my case, I'm not sure I can guess the correct timezone any better than PHP and it's no where near important enough to nag the user, so...
<?php
// Suppress DateTime warnings
date_default_timezone_set(@date_default_timezone_get());
?>
This function is not very useful for getting the OS timezone. One way to do it is to look at the results of 'timedatectl' from the OS. You can also look at the link from /etc/localtime
>file /etc/localtime
/etc/localtime: symbolic link to /usr/share/zoneinfo/America/Los_Angeles
>timedatectl
Local time: Thu 2020-12-24 07:11:27 PST
Universal time: Thu 2020-12-24 15:11:27 UTC
RTC time: Thu 2020-12-24 15:11:27
Time zone: America/Los_Angeles (PST, -0800)
System clock synchronized: yes
NTP service: active
RTC in local TZ: no
<?php
$dateinfo = trim(shell_exec("timedatectl | grep -i zone: 2>/dev/null"));
$dateinfoarray = explode(' ', $dateinfo);
echo 'Timezone = ' . $dateinfoarray[2] . PHP_EOL;
?>
Please note that "Damien dot Garrido dot Work at gmail dot com" code is wrong, the third parameter of sprintf must be divided by 60.
This is the corrected function:
<?php
function timezone_offset_string( $offset )
{
return sprintf( "%s%02d:%02d", ( $offset >= 0 ) ? '+' : '-', abs( $offset / 3600 ), abs( $offset % 3600 ) / 60 );
}
?>
You can use this function to convert given UTC datetime string to your application's local datetime:
<?php
function utc_to_local($utcDatetime, $format = 'Y-m-d H:i:s')
{
$currentTimeZone = date_default_timezone_get();
date_default_timezone_set('UTC');
$localDatetime = (new DateTime($utcDatetime))
->setTimeZone(new DateTimeZone($currentTimeZone));
date_default_timezone_set($currentTimeZone);
return $localDatetime->format($format);
}
To get offset string from offset:
<?php
function timezone_offset_string( $offset )
{
return sprintf( "%s%02d:%02d", ( $offset >= 0 ) ? '+' : '-', abs( $offset / 3600 ), abs( $offset % 3600 ) );
}
$offset = timezone_offset_get( new DateTimeZone( 'Pacific/Kiritimati' ), new DateTime() );
echo "offset: " . timezone_offset_string( $offset ) . "\n";
$offset = timezone_offset_get( new DateTimeZone( 'Pacific/Tahiti' ), new DateTime() );
echo "offset: " . timezone_offset_string( $offset ) . "\n";
?>
Output:
offset: +14:00
offset: -10:00
For the reason that date_default_timezone_get() throws an error when the timezone isn't set in php.ini and then returns a default chosen by the system (rather than returning false to indicate to the script that a timezone hasn't been set), I've found that the following works when you want a script to detect when the ini value has not been set and want the script itself to choose a default in that case, while still allowing bootstrap scripts to set their own default using date_default_timezone_set().
<?php
set_error_handler(function ($errno, $errstr){
throw new Exception($errstr);
return false;
});
try{
date_default_timezone_get();
}
catch(Exception $e){
date_default_timezone_set('UTC'); // Sets to UTC if not specified anywhere in .ini
}
restore_error_handler();
If you want to get the abbrivation (3 or 4 letter), instead of the long timezone string you can use date('T') function like this:
Input:
date_default_timezone_set('America/Los_Angeles');
echo date_default_timezone_get();
echo ' => '.date('e');
echo ' => '.date('T');
Output:
America/Los_Angeles => America/Los_Angeles => PST
date_default_timezone_get() will still emit a warning in E_STRICT if the timezone is not set; either by date_default_timezone_set() or the ini option of date.timezone.
This is probably not a big deal, but I thought I would contribute what I found.