timezone.php

<?php

namespace Goodby\TimeZone;

use Exception;
use DateTime;
use DateTimeZone;

class ReliableTimeZoneDateTime extends DateTime
{
	public function format($format)
	{
		throw new Exception('You can\'t call format(). Please call by formatWithTimezone()');
	}
	
	public function formatWithTimezone($format, $timezone)
	{
		return (new DateTime)
			->setTimestamp($this->getTimestamp())
			->setTimezone(new DateTimeZone($timezone))
			->format($format);
	}
}



// Server: Asia/Tokyo
// User: Asia/Shanghai

if (true) {
	define('ZEN_METRICS_CLIENT_TIMEZONE',  'Asia/Shanghai');
} else {
	define('ZEN_METRICS_CLIENT_TIMEZONE',  'UTC');
}

// model
$createdTime = (new ReliableTimeZoneDateTime())->setTimestamp(999994149);
var_dump($createdTime->formatWithTimezone(DATE_ATOM, date_default_timezone_get()));

echo '✄ - - - - - - - - - - - - - - - - - - - - - - - -', PHP_EOL;


// view
var_dump($createdTime->formatWithTimezone(DATE_ATOM, date_default_timezone_get()));
var_dump($createdTime->formatWithTimezone(DATE_ATOM, ZEN_METRICS_CLIENT_TIMEZONE));