您如何处理 PHP 中的时区差异计算?

I'm being told that this below method of calculating the user's local time is sometimes not working. What's the best way to do this in PHP? What do you do?

public function getTimeOffset ($time) {
    $this->_cacheTimeOffset();  
    if ($this->timeOffsetExecuted) {
        $d = date("O");
        $neg = 1;

        if (substr($d, 0, 1) == "-") {
            $neg = -1;
            $d = substr($d, 1);
        }

        $h = substr($d, 0, 2)*3600;
        $m = substr($d, 2)*60;

        return $time + ($neg * ($h + $m) * -1) + (($this->timeOffset + $this->getDstInUse()) * 3600);
    }
    return $time;
}

推荐答案

使用 DateTime 扩展，例如 日期时间::getOffset,
或 DateTimeZone::getOffset