My PHP script for comparing dates is not working properly - php

Question

I have 2 dates in the database. One is in the past, and other is in the future. I want to check if the current time is between those two dates. Everything works locally, but not on the server.
The server is in a different timezone, but if I echo the results (in comments), everything shows as it should. Dates in the database are saved in the correct timezone, so I do not apply setTimezone to those.
$timezone = new DateTimeZone('Europe/Belgrade');
$start_date = new DateTime($popup_start);
$end_date = new DateTime($popup_end);
$current_date = new DateTime();
$current_date->setTimezone($timezone);
//echo $start_date->format('Y-m-d H:i:s') .'<br>';
//echo $end_date->format('Y-m-d H:i:s') .'<br>';
//echo $current_date->format('Y-m-d H:i:s') .'<br>';
if($start_date < $current_date AND $end_date > $current_date) {
echo 'true';
}
else {
echo 'false';
}
The code above always goes to false for some reason.
Any help is appreciated

Answer 1

DateTime() is compared in UTC time reference (not based on format('Y-m-d H:i:s')).
The universal time reference (probably Unix Epoch seconds) is set on the DataTime instancing and does not change by ->setTimeZone(), that just affects the output, but it's still the same UTC time.
You have no TZ reference in the DB, so $start_date gets your local TZ when parsed. Let's say TZ_REMOTE is the timezone of the datestimes in the DB, and TZ_LOCAL is the local TZ. Then what happens is (pseudocode):
$start_date <- (($popup_start TZ_LOCAL)=>UTC)
$current_date <- (now()=>UTC)
So you have not gotten rid of the TZ difference in any way, it's still TZ_LOCAL dates.
What you can do is compare the textual representations, not the DateTimes:
if($popup_start < $current_date->format('Y-m-d H:I:s') && $popup_end > $current_date->format('Y-m-d H:I:s'))
Because, like I said, ->setTimeZone() will not alter the actual time, but it will alter the output of ->format() to convert the UTC datetime to the specified TZ.