PHP – Can’t set correct DateTimeZone to DateTime

Background

---

I have a list of events that are set to a certain (UK) time. I want users to see the time of the event in their local time. For example: if an event starts at 20:30 UK time a user from the Netherlands should see the start time as 21:30.

Problem

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I’ve got everything set up, and am creating new DateTime objects to set my events to. However, when I specify my DateTimeZone object it shows +00:00 in stead of the DateTimeZone I have created for it. This means that the new times are incorrect. So time that were set to 20:30 UK time still roll out as 20:30 NL time in stead of 21:30.

Code

---

This is the code I’ve written. As far as I’m aware everything I’m doing is correct, but the DateTimeZone is still incorrect when assigned to the DateTime object.

The default setting:

date_default_timezone_set('Europe/London');

The code that should convert DateTime objects to local time:

$user_timezone = Helper::get_user_timezone(); //contains "Europe/Amsterdam"
foreach($events as $event){
    $timestamp = $event->getDatetime()->getTimestamp();
    $local_datetime = new DateTime('@'.$timestamp, new DateTimeZone($user_timezone));
}

Input

---

I’ll use the following DateTime object as input:

DateTime Object
(
    [date] => 2015-02-14 19:30:00.000000
    [timezone_type] => 3
    [timezone] => Europe/London
)

Output

---

This outputs the following DateTime object for me:

DateTime Object
(
    [date] => 2015-02-14 19:30:00.000000
    [timezone_type] => 1
    [timezone] => +00:00
)

What have I tried

---

I’ve tried multiple things. Mostly it was about the order I set the DateTimeZone.

1. I tried creating a DateTimeZone before the creation of the DateTime object. I made sure it was a correct object and set it in the DateTime constructor then.
2. I tried creating a DateTime object first with just a timestamp as parameter, and setting the DateTimeZone object afterwards (I know there is/was a bug that caused some weird behaviour with setting DateTimeZone directly).
3. I’ve made sure the timezone I want to set (Europe/Amsterdam) is legit according to the docs.

I’m starting to wonder if it’s not possible to convert the date when using a timestamp?

I have also looked at these question for the basic gist, but they have no such problem:
1. Converting between timezones in PHP
2. How to convert between time zones in PHP using the DateTime class?

I followed a couple more, but I can’t find them at the moment.

Question

---

Why is my DateTime object getting an incorrect DateTimeZone?

Edit

---

After checking again that my DateTimeZone objects are correct I get the following:

DateTimeZone Object
(
    [timezone_type] => 3
    [timezone] => Europe/Amsterdam
)

But when I set it to the new DateTime object both the timezone_type and timezone change to:

DateTime Object
(
    [date] => 2015-02-14 19:30:00.000000
    [timezone_type] => 1
    [timezone] => +00:00
)

You’ll notice the different timezone_type and timezone.

Answer

Use method DateTime::setTimeZone():

date_default_timezone_set('Europe/London');

$date = new DateTime('2015-02-14 19:30:00');
print_r($date);
echo("Local time in London: ".$date->format('Y-m-d H:i:s')."n");

$date->setTimeZone(new DateTimeZone('Europe/Amsterdam'));
print_r($date);
echo("Local time in Amsterdam: ".$date->format('Y-m-d H:i:s')."n");

The output of the script above:

DateTime Object
(
    [date] => 2015-02-14 19:30:00.000000
    [timezone_type] => 3
    [timezone] => Europe/London
)
Local time in London: 2015-02-14 19:30:00
DateTime Object
(
    [date] => 2015-02-14 20:30:00.000000
    [timezone_type] => 3
    [timezone] => Europe/Amsterdam
)
Local time in Amsterdam: 2015-02-14 20:30:00

If you don’t want to modify the original $date object then you can clone it and modify the timezone of the clone:

$roDate = clone $date;
$roDate->setTimeZone(new DateTimeZone('Europe/Bucharest'));
echo("Local time in Bucharest: ".$roDate->format('Y-m-d H:i:s')."n");

displays:

Local time in Bucharest: 2015-02-14 21:30:00

Remarks

I ran the code with PHP 5.6.6 on OSX.

The DateTime and related classes had a lot of bugs in their early versions (PHP 5.2, PHP 5.3). Most of them were fixed in the recent versions (but there still are some well hidden minor issues).

My suggestion is to use the most recent version of PHP you can install on your system.