在 PHP 中设置时区偏移

Question

我正在编写一个 API，它将从传感器检索读数并返回时间和值列表，使用 Javascript 的 `new Date() 进行偏移。（原因见下文） p>

使用$date->sub(DateInterval::createFromDateString($offset . " minutes"))，我已经能够使时间加法/减法工作得很好，但返回的时间和日期的偏移量为+00:00（例如2016-02-26T13:32:28+00:00，而不是2016-02-26T13:32:28+11:00 用于澳大利亚)。

这会导致 Pebble 或 AngularJS 之类的东西出现问题，在看到偏移量为 +00:00 后，它们会在我自己的基础上应用自己的偏移量

调用$date->format("c")时如何正确设置偏移量？我应该自己编译日期（例如$date->format("Y-m-d\TH:i:s" . $plusOrMinus . $myoffset->format("h:i"))）还是有更好的方法？

编辑：由于平台限制（例如 Pebble 智能手表），我不能或不想使用时区名称，因为在我的手表应用程序中实现时区菜单会破坏 UX 或驱动文件大小如果我向时区表/库添加偏移量

Answer 1

我最终解决了这个问题。来自PHP manual 的这条信息告诉了我：

当 $time 参数是 UNIX 时间戳（例如 @946684800）或指定时区（例如 2010-01-28T15:00:00+02:00）时，$timezone 参数和当前时区将被忽略。

所以我最终的解决方案是扩展DateTime 类并覆盖__construct() 方法。我修改的类如下：

<?php

  class timezone extends DateTime {

    // Override our __construct method
    function __construct($date = "now", $offset = null) {
      // If we've not specified an offset
      if(is_null($offset)) {
          // Assume UTC
          $offsetFormat = "+00:00";
          $offset = 0;
      // Otherwise..
      } else {
        // Create a new DateTime, and get the difference between that, and another new DateTime that has $offset minutes subtracted from it. Format the results as something like +11:00 or -03:00
        $offsetFormat = (new DateTime($date, new DateTimeZone("UTC")))->diff((new DateTime($date, new DateTimeZone("UTC")))->sub(DateInterval::createFromDateString($offset . " minutes")))->format("%R%H:%I");
      }

      // Next, we get the offset from our $date. If this offset (divided by 60, as we're working in minutes, not in seconds) does NOT equal our offset
      if((new DateTime($date))->getOffset() / 60 !== $offset) {
        // Overwrite $date, and set it to a new DateTime with $offset minutes subtracted from it
        $date = (new DateTime($date, new DateTimeZone("UTC")))->sub(DateInterval::createFromDateString($offset . " minutes"));
      // If $date's offset equals $offset
      } else {
        // An offset has already been applied (we know this because all our pre-offset dates will be in UTC), and we don't need to do it again
        $date = (new DateTime($date));
      }

      // Finally, hand this back to the original DateTime class. This format works out to be something like: 2016-03-10T23:16:37+11:00
      parent::__construct($date->format("Y-m-d\TH:i:s") . $offsetFormat, null);
    }

  }


  echo (new timezone())->format("c") . "<br />"; // Will output something like 2016-03-10T12:17:44+00:00
  echo (new timezone(null, -660))->format("c") . "<br />"; // Will output something like 2016-03-10T23:17:44+11:00
  echo (new timezone("midnight", -660))->format("c") . "<br />"; // Will output 2016-03-10T11:00:00+11:00
  echo (new timezone("midnight"))->format("c") . "<br />"; // Will output 2016-03-10T00:00:00+00:00
  echo (new timezone("2016-01-01T00:00+00:00", -660))->format("c") . "<br />"; // Will output 2016-01-01T11:00:00+11:00
  echo (new timezone("2016-01-01T00:00+11:00", -660))->format("c") . "<br />"; // Will output 2016-01-01T11:00:00+11:00. Note that the offset isn't applied twice!

 ?>

编辑：现在这是我开源的一个库。 Check it out over on GitHub

Answer 2

这是？

$date = new DateTime('now', new DateTimeZone('Australia/Adelaide'));
var_dump($date);
var_dump($date->format('c'));

输出是

object(DateTime)[2]
  public 'date' => string '2016-02-26 13:35:48.000000' (length=26)
  public 'timezone_type' => int 3
  public 'timezone' => string 'Australia/Adelaide' (length=18)
string '2016-02-26T13:35:48+10:30' (length=25)