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kolab_sync_timezone_converter.php
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kolab_sync_timezone_converter.php
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<?php
/**
+--------------------------------------------------------------------------+
| Kolab Sync (ActiveSync for Kolab) |
| |
| Copyright (C) 2011-2017, Kolab Systems AG <contact@kolabsys.com> |
| Copyright (C) 2008-2012, Metaways Infosystems GmbH |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU Affero General Public License as published |
| by the Free Software Foundation, either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU Affero General Public License for more details. |
| |
| You should have received a copy of the GNU Affero General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/> |
+--------------------------------------------------------------------------+
| Author: Aleksander Machniak <machniak@kolabsys.com> |
| Author: Jonas Fischer <j.fischer@metaways.de> |
+--------------------------------------------------------------------------+
*/
/**
* Activesync timezone converter
*/
class kolab_sync_timezone_converter
{
/**
* holds the instance of the singleton
*
* @var kolab_sync_timezone_onverter
*/
private static $_instance = NULL;
protected $_startDate = array();
/**
* If set then the timezone guessing results will be cached.
* This is strongly recommended for performance reasons.
*
* @var rcube_cache
*/
protected $cache = null;
/**
* array of offsets known by ActiceSync clients, but unknown by php
* @var array
*/
protected $_knownTimezones = array(
'0AIAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA==' => array(
'Pacific/Kwajalein' => 'MHT'
)
);
protected $_legacyTimezones = array(
# This is an outdated timezone that outlook keeps sending because of an outdate timezone database on windows
'Lv///0kAcgBhAG4AIABTAHQAYQBuAGQAYQByAGQAIABUAGkAbQBlAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAkABAADABcAOwA7AOcDAAAAAEkAcgBhAG4AIABEAGEAeQBsAGkAZwBoAHQAIABUAGkAbQBlAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMAAwAEAAAAAAAAAAAAxP///w==' => array(
'Asia/Tehran' => '+0330'
)
);
/**
* don't use the constructor. Use the singleton.
*
* @param $_logger
*/
private function __construct()
{
}
/**
* don't clone. Use the singleton.
*/
private function __clone()
{
}
/**
* the singleton pattern
*
* @return kolab_sync_timezone_converter
*/
public static function getInstance()
{
if (self::$_instance === NULL) {
self::$_instance = new kolab_sync_timezone_converter();
}
return self::$_instance;
}
/**
* Returns a timezone with an offset matching the time difference
* of $dt from $referenceDt.
*
* If set and matching the offset, kolab_format::$timezone is preferred.
*
* @param DateTime $dt The date time value for which we
* calculate the offset.
* @param DateTime $referenceDt The reference value, for instance in UTC.
*
* @return DateTimeZone|null
*/
public function getOffsetTimezone($dt, $referenceDt)
{
$interval = $referenceDt->diff($dt);
$tz = new DateTimeZone($interval->format('%R%H%I')); //e.g. +0200
$utcOffset = $tz->getOffset($dt);
//Prefer the configured timezone if it matches the offset.
if (kolab_format::$timezone) {
if (kolab_format::$timezone->getOffset($dt) == $utcOffset) {
return kolab_format::$timezone;
}
}
//Look for any timezone with a matching offset.
foreach (DateTimeZone::listIdentifiers() as $timezoneIdentifier) {
$timezone = new DateTimeZone($timezoneIdentifier);
if ($timezone->getOffset($dt) == $utcOffset) {
return $timezone;
}
}
return null;
}
/**
* Returns a list of timezones that match to the {@param $_offsets}
*
* If {@see $_expectedTimezone} is set then the method will terminate as soon
* as the expected timezone has matched and the expected timezone will be the
* first entry to the returned array.
*
* @param string|array $_offsets
*
* @return array
*/
public function getListOfTimezones($_offsets)
{
if (is_string($_offsets) && isset($this->_knownTimezones[$_offsets])) {
$timezones = $this->_knownTimezones[$_offsets];
}
elseif (is_string($_offsets) && isset($this->_legacyTimezones[$_offsets])) {
$timezones = $this->_legacyTimezones[$_offsets];
}
else {
if (is_string($_offsets)) {
// unpack timezone info to array
$_offsets = $this->_unpackTimezoneInfo($_offsets);
}
if (!$this->_validateOffsets($_offsets)) {
return array();
}
$this->_setDefaultStartDateIfEmpty($_offsets);
$timezones = array();
foreach (DateTimeZone::listIdentifiers() as $timezoneIdentifier) {
$timezone = new DateTimeZone($timezoneIdentifier);
if (false !== ($matchingTransition = $this->_checkTimezone($timezone, $_offsets))) {
$timezones[$timezoneIdentifier] = $matchingTransition['abbr'];
}
}
}
return $timezones;
}
/**
* Returns PHP timezone that matches to the {@param $_offsets}
*
* If {@see $_expectedTimezone} is set then the method will return this timezone if it matches.
*
* @param string|array $_offsets Activesync timezone definition
* @param string $_expectedTomezone Expected timezone name
*
* @return string Expected timezone name
*/
public function getTimezone($_offsets, $_expectedTimezone = null)
{
$timezones = $this->getListOfTimezones($_offsets);
if ($_expectedTimezone && isset($timezones[$_expectedTimezone])) {
return $_expectedTimezone;
}
else {
return key($timezones);
}
}
/**
* Return packed string for given {@param $_timezone}
*
* @param string $_timezone Timezone identifier
* @param string|int $_startDate Start date
*
* @return string Packed timezone offsets
*/
public function encodeTimezone($_timezone, $_startDate = null)
{
foreach ($this->_knownTimezones as $packedString => $knownTimezone) {
if (array_key_exists($_timezone, $knownTimezone)) {
return $packedString;
}
}
$offsets = $this->getOffsetsForTimezone($_timezone, $_startDate);
return $this->_packTimezoneInfo($offsets);
}
/**
* Get offsets for given timezone
*
* @param string $_timezone Timezone identifier
* @param string|int $_startDate Start date
*
* @return array Timezone offsets
*/
public function getOffsetsForTimezone($_timezone, $_startDate = null)
{
$this->_setStartDate($_startDate);
$offsets = $this->_getOffsetsTemplate();
try {
$timezone = new DateTimeZone($_timezone);
}
catch (Exception $e) {
return null;
}
list($standardTransition, $daylightTransition) = $this->_getTransitionsForTimezoneAndYear($timezone, $this->_startDate['year']);
if ($standardTransition) {
$offsets['bias'] = $standardTransition['offset']/60*-1;
if ($daylightTransition) {
$offsets = $this->_generateOffsetsForTransition($offsets, $standardTransition, 'standard', $timezone);
$offsets = $this->_generateOffsetsForTransition($offsets, $daylightTransition, 'daylight', $timezone);
//@todo how do we get the standardBias (is usually 0)?
//$offsets['standardBias'] = ...
$offsets['daylightBias'] = ($daylightTransition['offset'] - $standardTransition['offset'])/60*-1;
$offsets['standardHour'] -= $offsets['daylightBias'] / 60;
$offsets['daylightHour'] += $offsets['daylightBias'] / 60;
}
}
return $offsets;
}
/**
* Get offsets for timezone transition
*
* @param array $_offsets Timezone offsets
* @param array $_transition Timezone transition information
* @param string $_type Transition type: 'standard' or 'daylight'
* @param DateTimeZone $_timezone Timezone of the transition
*
* @return array
*/
protected function _generateOffsetsForTransition(array $_offsets, array $_transition, $_type, $_timezone)
{
$transitionDate = new DateTime($_transition['time'], $_timezone);
if ($_transition['offset']) {
$transitionDate->modify($_transition['offset'] . ' seconds');
}
$_offsets[$_type . 'Month'] = (int) $transitionDate->format('n');
$_offsets[$_type . 'DayOfWeek'] = (int) $transitionDate->format('w');
$_offsets[$_type . 'Minute'] = (int) $transitionDate->format('i');
$_offsets[$_type . 'Hour'] = (int) $transitionDate->format('G');
for ($i=5; $i>0; $i--) {
if ($this->_isNthOcurrenceOfWeekdayInMonth($transitionDate, $i)) {
$_offsets[$_type . 'Week'] = $i;
break;
};
}
return $_offsets;
}
/**
* Test if the weekday of the given {@param $_timestamp} is the {@param $_occurence}th occurence of this weekday within its month.
*
* @param DateTime $_datetime
* @param int $_occurence [1 to 5, where 5 indicates the final occurrence during the month if that day of the week does not occur 5 times]
*
* @return bool
*/
protected function _isNthOcurrenceOfWeekdayInMonth($_datetime, $_occurence)
{
if ($_occurence <= 1) {
return true;
}
$orig = $_datetime->format('n');
if ($_occurence == 5) {
$modified = clone($_datetime);
$modified->modify('1 week');
$mod = $modified->format('n');
// modified date is a next month
return $mod > $orig || ($mod == 1 && $orig == 12);
}
$modified = clone($_datetime);
$modified->modify(sprintf('-%d weeks', $_occurence - 1));
$mod = $modified->format('n');
if ($mod != $orig) {
return false;
}
$modified = clone($_datetime);
$modified->modify(sprintf('-%d weeks', $_occurence));
$mod = $modified->format('n');
// modified month is earlier than original
return $mod < $orig || ($mod == 12 && $orig == 1);
}
/**
* Check if the given {@param $_standardTransition} and {@param $_daylightTransition}
* match to the object property {@see $_offsets}
*
* @param array $standardTransition
* @param array $daylightTransition
*
* @return bool
*/
protected function _checkTransition($_standardTransition, $_daylightTransition, $_offsets, $tz)
{
if (empty($_standardTransition) || empty($_offsets)) {
return false;
}
$standardOffset = ($_offsets['bias'] + $_offsets['standardBias']) * 60 * -1;
// check each condition in a single if statement and break the chain when one condition is not met - for performance reasons
if ($standardOffset == $_standardTransition['offset']) {
if (empty($_offsets['daylightMonth']) && (empty($_daylightTransition) || empty($_daylightTransition['isdst']))) {
// No DST
return true;
}
$daylightOffset = ($_offsets['bias'] + $_offsets['daylightBias']) * 60 * -1;
// the milestone is sending a positive value for daylightBias while it should send a negative value
$daylightOffsetMilestone = ($_offsets['bias'] + ($_offsets['daylightBias'] * -1) ) * 60 * -1;
if (
!empty($_daylightTransition)
&& ($daylightOffset == $_daylightTransition['offset'] || $daylightOffsetMilestone == $_daylightTransition['offset'])
) {
// date-time input here contains UTC timezone specifier (+0000),
// we have to convert the date to the requested timezone afterwards.
$standardDate = new DateTime($_standardTransition['time']);
$daylightDate = new DateTime($_daylightTransition['time']);
$standardDate->setTimezone($tz);
$daylightDate->setTimezone($tz);
if ($standardDate->format('n') == $_offsets['standardMonth'] &&
$daylightDate->format('n') == $_offsets['daylightMonth'] &&
$standardDate->format('w') == $_offsets['standardDayOfWeek'] &&
$daylightDate->format('w') == $_offsets['daylightDayOfWeek']
) {
return $this->_isNthOcurrenceOfWeekdayInMonth($daylightDate, $_offsets['daylightWeek']) &&
$this->_isNthOcurrenceOfWeekdayInMonth($standardDate, $_offsets['standardWeek']);
}
}
}
return false;
}
/**
* decode timezone info from activesync
*
* @param string $_packedTimezoneInfo the packed timezone info
* @return array
*/
protected function _unpackTimezoneInfo($_packedTimezoneInfo)
{
$timezoneUnpackString = 'lbias/a64standardName/vstandardYear/vstandardMonth/vstandardDayOfWeek/vstandardWeek/vstandardHour/vstandardMinute/vstandardSecond/vstandardMilliseconds/lstandardBias'
. '/a64daylightName/vdaylightYear/vdaylightMonth/vdaylightDayOfWeek/vdaylightWeek/vdaylightHour/vdaylightMinute/vdaylightSecond/vdaylightMilliseconds/ldaylightBias';
$timezoneInfo = unpack($timezoneUnpackString, base64_decode($_packedTimezoneInfo));
if ($timezoneInfo['standardHour'] == 23 && $timezoneInfo['standardMilliseconds'] == 999
&& $timezoneInfo['standardMinute'] == 59 && $timezoneInfo['standardSecond'] == 59
) {
$timezoneInfo['standardHour'] = 24;
$timezoneInfo['standardMinute'] = 0;
$timezoneInfo['standardSecond'] = 0;
$timezoneInfo['standardMilliseconds'] = 0;
}
return $timezoneInfo;
}
/**
* encode timezone info to activesync
*
* @param array $_timezoneInfo
* @return string
*/
protected function _packTimezoneInfo($_timezoneInfo)
{
if (!is_array($_timezoneInfo)) {
return null;
}
// According to e.g. https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-systemtime,
// 24 is not allowed in the Hour field, and consequently Outlook can't deal with it.
// This is the same workaround that Outlook applies.
if ($_timezoneInfo['standardHour'] == 24) {
$_timezoneInfo['standardHour'] = 23;
$_timezoneInfo['standardMinute'] = 59;
$_timezoneInfo['standardSecond'] = 59;
$_timezoneInfo['standardMilliseconds'] = 999;
}
$packed = pack(
"la64vvvvvvvvla64vvvvvvvvl",
$_timezoneInfo['bias'],
$_timezoneInfo['standardName'],
$_timezoneInfo['standardYear'],
$_timezoneInfo['standardMonth'],
$_timezoneInfo['standardDayOfWeek'],
$_timezoneInfo['standardWeek'],
$_timezoneInfo['standardHour'],
$_timezoneInfo['standardMinute'],
$_timezoneInfo['standardSecond'],
$_timezoneInfo['standardMilliseconds'],
$_timezoneInfo['standardBias'],
$_timezoneInfo['daylightName'],
$_timezoneInfo['daylightYear'],
$_timezoneInfo['daylightMonth'],
$_timezoneInfo['daylightDayOfWeek'],
$_timezoneInfo['daylightWeek'],
$_timezoneInfo['daylightHour'],
$_timezoneInfo['daylightMinute'],
$_timezoneInfo['daylightSecond'],
$_timezoneInfo['daylightMilliseconds'],
$_timezoneInfo['daylightBias']
);
return base64_encode($packed);
}
/**
* Returns complete offsets array with all fields empty
*
* Used e.g. when reverse-generating ActiveSync Timezone Offset Information
* based on a given Timezone, {@see getOffsetsForTimezone}
*
* @return unknown_type
*/
protected function _getOffsetsTemplate()
{
return array(
'bias' => 0,
'standardName' => '',
'standardYear' => 0,
'standardMonth' => 0,
'standardDayOfWeek' => 0,
'standardWeek' => 0,
'standardHour' => 0,
'standardMinute' => 0,
'standardSecond' => 0,
'standardMilliseconds' => 0,
'standardBias' => 0,
'daylightName' => '',
'daylightYear' => 0,
'daylightMonth' => 0,
'daylightDayOfWeek' => 0,
'daylightWeek' => 0,
'daylightHour' => 0,
'daylightMinute' => 0,
'daylightSecond' => 0,
'daylightMilliseconds' => 0,
'daylightBias' => 0
);
}
/**
* Validate and set offsets
*
* @param array $value
*
* @return bool Validation result
*/
protected function _validateOffsets($value)
{
// validate $value
if ((!empty($value['standardMonth']) || !empty($value['standardWeek']) || !empty($value['daylightMonth']) || !empty($value['daylightWeek'])) &&
(empty($value['standardMonth']) || empty($value['standardWeek']) || empty($value['daylightMonth']) || empty($value['daylightWeek']))
) {
// It is not possible not set standard offsets without setting daylight offsets and vice versa
return false;
}
return true;
}
/**
* Parse and set object property {@see $_startDate}
*
* @param string|int $_startDate
* @return void
*/
protected function _setStartDate($_startDate)
{
if (empty($_startDate)) {
$this->_setDefaultStartDateIfEmpty();
return;
}
$startDateParsed = array();
if (is_string($_startDate)) {
$startDateParsed['string'] = $_startDate;
$startDateParsed['ts'] = strtotime($_startDate);
}
else if (is_int($_startDate)) {
$startDateParsed['ts'] = $_startDate;
$startDateParsed['string'] = date('Y-m-d', $_startDate);
}
else {
$this->_setDefaultStartDateIfEmpty();
return;
}
$startDateParsed['object'] = new DateTime($startDateParsed['string']);
$startDateParsed = array_merge($startDateParsed, getdate($startDateParsed['ts']));
$this->_startDate = $startDateParsed;
}
/**
* Set default value for object property {@see $_startdate} if it is not set yet.
* Tries to guess the correct startDate depending on object property {@see $_offsets} and
* falls back to current date.
*
* @param array $_offsets [offsets may be avaluated for a given start year]
* @return void
*/
protected function _setDefaultStartDateIfEmpty($_offsets = null)
{
if (!empty($this->_startDate)) {
return;
}
if (!empty($_offsets['standardYear'])) {
$this->_setStartDate($_offsets['standardYear'].'-01-01');
}
else {
$this->_setStartDate(time());
}
}
/**
* Check if the given {@param $_timezone} matches the {@see $_offsets}
* and also evaluate the daylight saving time transitions for this timezone if necessary.
*
* @param DateTimeZone $timezone
* @param array $offsets
*
* @return array|bool
*/
protected function _checkTimezone(DateTimeZone $timezone, $offsets)
{
list($standardTransition, $daylightTransition) = $this->_getTransitionsForTimezoneAndYear($timezone, $this->_startDate['year']);
if ($this->_checkTransition($standardTransition, $daylightTransition, $offsets, $timezone)) {
return $standardTransition;
}
return false;
}
/**
* Returns the standard and daylight transitions for the given {@param $_timezone}
* and {@param $_year}.
*
* @param DateTimeZone $_timezone
* @param int $_year
*
* @return array
*/
protected function _getTransitionsForTimezoneAndYear(DateTimeZone $_timezone, $_year)
{
$standardTransition = null;
$daylightTransition = null;
$start = mktime(0, 0, 0, 12, 1, $_year - 1);
$end = mktime(24, 0, 0, 12, 31, $_year);
$transitions = $_timezone->getTransitions($start, $end);
if ($transitions === false) {
return array();
}
foreach ($transitions as $index => $transition) {
if (date('Y', $transition['ts']) == $_year) {
if (isset($transitions[$index+1]) && date('Y', $transitions[$index]['ts']) == date('Y', $transitions[$index+1]['ts'])) {
$daylightTransition = $transition['isdst'] ? $transition : $transitions[$index+1];
$standardTransition = $transition['isdst'] ? $transitions[$index+1] : $transition;
}
else {
$daylightTransition = $transition['isdst'] ? $transition : null;
$standardTransition = $transition['isdst'] ? null : $transition;
}
break;
}
else if ($index == count($transitions) -1) {
$standardTransition = $transition;
}
}
return array($standardTransition, $daylightTransition);
}
}

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kolab_sync_timezone_converter.php (22 KB)

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