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Does anyone know PHP code to correct the conflictive time change in a country?

For example, when a country changes time, there are 2 possibilities:

1.- If it changes to an earlier time, for example, at 3 Am in Central Europe, the last Sunday in October at 3 Am becomes 2 Am, therefore, if there is a date that is 02:30 am, 2 Dates and Hours are possible, one before the Change, and one after the Change.

2.- In Central Europe the Last Sunday of March at 2 Am becomes 3 Am, therefore if someone puts a date/time like this: 03-31-2024 at 02:30 Am, that LOCAL time It is theoretically impossible, since between 2 and 3 there is no possibility of Local Time.

Is there any code that warns about this?

For example, I have this code in PHP, I pass it a time zone, and it does not warn me that this time, 02:30:00Am, is not officially possible, and I would like it to warn me about these conflicting hours:

https://timezonespro.com/php/test4.php?tzname=Europe/Madrid

<?php
$timezoneStr = $_GET["tzname"];
echo "TimeZone = " . $timezoneStr;


$datetime = "2024-03-31 02:30:00";
print '<br>';
echo "Local = " . $datetime;
$given = new DateTime($datetime, new DateTimeZone($timezoneStr));
$given->setTimezone(new DateTimeZone("UTC"));
$output = $given->format("Y-m-d H:i:s"); 
print '<br>';
echo "UTC = " . $output;

$ano = substr($output, 0, 4);
$mes = substr($output, 5, 2);
$dia = substr($output, 8, 2);
$hor = substr($output, 11, 2);
$min = substr($output, 14, 2);
$sec = substr($output, 17, 2);
print '<br>';
echo "Year = " . $ano;
print '<br>';
echo "Month = " . $mes;
print '<br>';
echo "Day = " . $dia;
print '<br>';
echo "Hours = " . $hor;
print '<br>';
echo "Minutes = " . $min;
print '<br>';
echo "Seconds = " . $sec;

$meses = ["Enero", "Febrero", "Marzo", "Abril", "Mayo", "Junio", "Julio", "Agosto", "Septiembre", "Octubre", "Noviembre", "Diciembre"];
$mesStr = $meses[intval($mes) - 1];

print '<br>';
echo $dia . "-" . $mesStr . "-" . $ano . " a las " . $hor . ":" . $min . ":" . $sec;

$secondsInTime = intval($hor * 3600) + intval($min * 60) + intval($sec);
$secondsInTimeDec = $secondsInTime / 86400;

$jd = GregorianToJD($mes, $dia, $ano);
$jdDec = intval($jd) + $secondsInTimeDec;
print '<br>';
echo "JulianDay = " . $jdDec;
?>

A code that warns of conflicting times in time changes in a country.

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2

Answers


  1. Chosen as BEST ANSWER
    0

    A little error in my code in the JulianDay, correction:

        <?php
$timezoneStr = $_GET["tzname"];
echo "TimeZone = " . $timezoneStr;


$datetime = "2024-03-31 02:30:00";
print '<br>';
echo "Local = " . $datetime;
//$given = new DateTime($datetime, new DateTimeZone("Europe/Madrid"));
$given = new DateTime($datetime, new DateTimeZone($timezoneStr));
$given->setTimezone(new DateTimeZone("UTC"));
$output = $given->format("Y-m-d H:i:s"); 
print '<br>';
echo "UTC = " . $output;

$ano = substr($output, 0, 4);
$mes = substr($output, 5, 2);
$dia = substr($output, 8, 2);
$hor = substr($output, 11, 2);
$min = substr($output, 14, 2);
$sec = substr($output, 17, 2);
print '<br>';
echo "Year = " . $ano;
print '<br>';
echo "Month = " . $mes;
print '<br>';
echo "Day = " . $dia;
print '<br>';
echo "Hours = " . $hor;
print '<br>';
echo "Minutes = " . $min;
print '<br>';
echo "Seconds = " . $sec;

$meses = ["Enero", "Febrero", "Marzo", "Abril", "Mayo", "Junio", "Julio", "Agosto", "Septiembre", "Octubre", "Noviembre", "Diciembre"];
$mesStr = $meses[intval($mes) - 1];

print '<br>';
echo $dia . "-" . $mesStr . "-" . $ano . " a las " . $hor . ":" . $min . ":" . $sec;

if (intval($hor) >= 12)
    $secondsInTime = intval($hor * 3600) + intval($min * 60) + intval($sec);
else
    $secondsInTime = intval($hor * 3600) + intval(12 * 3600) + intval($min * 60) + intval($sec);
$secondsInTimeDec = $secondsInTime / 86400;

$jd = GregorianToJD($mes, $dia, $ano);
$jdDec = intval($jd) + $secondsInTimeDec;
print '<br>';
echo "JulianDay = " . $jdDec;
?>

    The correction is this part:

    if (intval($hor) >= 12)
    $secondsInTime = intval($hor * 3600) + intval($min * 60) + intval($sec);
else
    $secondsInTime = intval($hor * 3600) + intval(12 * 3600) + intval($min * 60) + intval($sec);

    And well, it is possible to list all the time changes, and search for the dates that have these problems, but I was looking to see if there was someone who had already done it.

    For example, with this code you can list all changes in the "Europe/Madrid" TimeZone:

    All TimeZone changes for Europe/Madrid

    Code:

    <?php
$timezoneStr = $_GET["tzname"];
print_r('timezone = ' . $timezoneStr . '@');
print '<br>';
$timezone_identifiers = DateTimeZone::listIdentifiers();
for ($i=0; $i < 1005; $i++)
    {
    if ($timezone_identifiers[$i] == "")
        break;
    else if ($timezone_identifiers[$i] == $timezoneStr)
        {
        $timezone = new DateTimeZone($timezone_identifiers[$i]);
        $transitions = $timezone->getTransitions();
        for ($k=0; $k<500; $k++)
            {
            if ($transitions[$k] == "")
                break;
            $UnixTimeStamp = $transitions[$k][ts];
            $julianDay = ($UnixTimeStamp / 86400) + 2440587.5;
            print_r('UnixTimeStamp = ' . $UnixTimeStamp . ' | ');
            print_r('JulianDay = ' . $julianDay . ' | ');
            print_r('DateTime (Time) = ' . $transitions[$k][time] . ' | ');
            print_r('Seconds Difference to GMT (Offset) = ' . $transitions[$k][offset] . ' | ');
            print_r('Is Dst (IsDst) = ' . $transitions[$k][isdst] . ' | ');
            print_r('TimeZone Abreviation (Abbr) = ' . $transitions[$k][abbr] . '@');
            Print '<br>';
            }
        return;
        }
    }
return;

    ?>

    I'm looking to see if there was already someone who had done it. Well, it should be something that has been done for a long time, these types of problems with time changes are always there.

    And I think that php should already have it corrected, and when there are officially impossible hours, notify, and when there are possible double hours, also notify.


  2. 0

    DateTime already handles such cases:

    $dt = new DateTime('2024-03-31 02:30:00', new DateTimeZone('Europe/Madrid'));
echo $dt->format('Y-m-d H:i:s'); // prints: 2024-03-31 03:30:00

    Notice how the "impossible" 02:30 became 03:30 automatically.

    There is no warning, but you can always compare the formatted Y-m-d H:i:s strings of the date with and without timezone info, if you need to check if that happened.

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