PHP Server time is behind local time - php

Question

my server time is ahead of my local time (I cannot change my server time) by about 4 hours. The server is hosted in a different time zone, and changing the server time would have too many far reaching effects on too many other things.
Anyways, I have customers that place an order for a Gift Card for instance, and the gift card is dated to be sent out the same day that they ordered it, so the date stamp that gets placed on the Gift Card is (for instance), 1/3/2018.
But, let's say they placed the gift card order at 11:30 PM, and the server time has already moved onto 1/4/2018. My code below does not account for that:
$curDate = date('Y-m-d');
if ($card->getCardStatus() == 0){
if ((($card->getMailDeliveryDate() == null) || ($curDate == $card->getMailDeliveryDate())) && $card->getCardType() != 'offline') {
$card->setCardStatus(1);
$card->save();
$card->send();
}
}
Any ideas on how to take this scenario into account?
Thank you.
Edit Awh man, I got my question reversed around. My local time is ahead of my server time. I apologize. My Magento is set to eastern time (where I'm at) but the server itself is located in LA, thus PST. I don't want to change the timezone, I just want to make sure that orders placed in other time zones are accounted for.

Answer 1

This is where the PHP date_default_timezone_set() function steps in.
date_default_timezone_set — Sets the default timezone used by all date/time functions in a script
Set the default_timezone like this:
date_default_timezone_set('America/Los_Angeles');
More here http://php.net/date-default-timezone-set.
EDIT: As suggested by #RamKesavan, you can also set the timezone in Magento settings by doing this:
First set global timezone to GMT or UTC:
1.) Go to System -> Settings
2.) Edit your default scope
3.) Go to Configuration -> General -> General -> Locale Options
4.) Select GMT Standard Time (or UTC)
Then you need to set your default website scope to your preferred time zone like this:
1.) Go to System -> Settings
2.) Select the scope for each of your websites.
3.) Go to Configuration -> General -> General -> Locale Options again.
4.) Select W. European Standard Time (Europe/Berlin or Europe/Amsterdam) or select some other timezone appropriate for the location of your customers.
5.)Repeat for the next website.
The default website scope will ensure that your websites display Dutch, Chinese or American order and shipping times, or some other time according to your settings.
More here https://support.hypernode.com/magento-utc-hypernode.
EDIT 2: (OP changed the question)
It is impossible to detect the user date time locale settings with accuracy from the server side (PHP). This is what the client side (javascript) is used for.
There is a javascript script available jstimezonedetect which is used to easily detect the user time zone settings. Download the script and include it in the page where you have the purhase form.
To retrieve the timezone and send it with the purchase form you can add a hidden field inside the purchase form (it will be sent with the form) like this:
var tz = jstz.determine(); // call the jstimezonedetect script object
var tzName = tz.name(); // name of the user timezone 'Europe/Berlin'
var hiddenTimezone = document.getElementById('myHiddenTimezone');
hiddenTimezone.value = tzName; // add timezone value to hidden field
And in HTML you would need to have the hidden element added inside the purchase form like this:
<form ...>
// ...
// ...
<input type="hidden" id="myHiddenTimezone" name="userTimezone" value="" />
<!-- since the hidden element is inside the form and has a name -->
<!-- it will be sent with the form -->
// ...
</form>
On the server side (receiving side) you would get the timezone like this:
$userTimezone = $_POST['userTimezone']; // or $_GET['userTimezone'] if form method was GET
When a purchase occurs, you now have the server time and the user timezone. You can make 3 columns in your table. One for server time, another for user time zone and the third the current (calculated) user time.
You can then extract whichever column you wish and you would know for sure what you are getting from the database and how to write a PHP function to handle it.
EDIT 3:
To simply convert the a date from for example PST to EST you would do this:
$ESTDate = new DateTime('2017-02-04 12:32:43', new DateTimeZone('America/Los_Angeles'));
$ESTDate->setTimezone(new DateTimeZone('America/New_York'));
If you wish to echo the datetime with formatting:
echo $ESTDate->format('Y-m-d H:i:s');
If you wish to compare to another date you can use:
$difference = $ESTDate1->diff($ESTDate2);
which will produce results like this:
DateInterval Object
(
[y] => 3
[m] => 5
[d] => 15
[h] => 0
[i] => 0
[s] => 0
[invert] => 0
[days] => 1264
)
// usage
if($difference['days'] == 0)
// ...
Or you can use the > < and other operators like this:
// both dates must be in the same format (example: 'Y-m-d h:i:s')
if( $ESTDate1 > $ESTDate2) // date1 is greater
else // date2 is greater or equal