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kolab_sync_timezone_converter.php
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kolab_sync_timezone_converter.php
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<?php
/**
* Tine 2.0
*
* @package ActiveSync
* @license http://www.tine20.org/licenses/agpl-nonus.txt AGPL Version 1 (Non-US)
* NOTE: According to sec. 8 of the AFFERO GENERAL PUBLIC LICENSE (AGPL),
* Version 1, the distribution of the Tine 2.0 ActiveSync module in or to the
* United States of America is excluded from the scope of this license.
* @copyright Copyright (c) 2009 Metaways Infosystems GmbH (http://www.metaways.de)
* @author Jonas Fischer <j.fischer@metaways.de>
*/
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'
)
);
/**
* 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 an array 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
* @param string $_expectedTimezone Expected timezone
*
* @return array
*/
public function getListOfTimezones($_offsets, $_expectedTimezone = null)
{
if (is_string($_offsets) && isset($this->_knownTimezones[$_offsets])) {
$timezones = $this->_knownTimezones[$_offsets];
}
else {
if (is_string($_offsets)) {
// unpack timezone info to array
$_offsets = $this->_unpackTimezoneInfo($_offsets);
}
if (!$this->_validateOffsets($_offsets)) {
return array();
}
$this->_setDefaultStartDateIfEmpty($_offsets);
// don't use __METHOD__ ":" is not allowed as cache identifier
$cacheId = $this->_getCacheId('timezones', $_offsets);
$timezones = $this->_loadFromCache($cacheId);
if (!is_array($timezones)) {
$timezones = array();
foreach (DateTimeZone::listIdentifiers() as $timezoneIdentifier) {
$timezone = new DateTimeZone($timezoneIdentifier);
if (false !== ($matchingTransition = $this->_checkTimezone($timezone, $_offsets))) {
if ($timezoneIdentifier === $_expectedTimezone) {
$timezones = array($timezoneIdentifier => $matchingTransition['abbr']);
break;
}
else {
$timezones[$timezoneIdentifier] = $matchingTransition['abbr'];
}
}
}
$this->_saveInCache($timezones, $cacheId);
}
}
// $this->_log(__METHOD__, __LINE__, 'Matching timezones: '.print_r($timezones, true));
// if (empty($timezones)) {
// throw new ActiveSync_TimezoneNotFoundException('No timezone found for the given offsets');
// }
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, $_expectedTimezone);
if ($_expectedTimezone && isset($timezones[$_expectedTimezone])) {
return $_expectedTimezone;
}
else {
return current($timezones);
}
}
/**
* Unpacks {@param $_packedTimezoneInfo} using {@see unpackTimezoneInfo} and then
* calls {@see getTimezoneForOffsets} with the unpacked timezone info
*
* @param String $_packedTimezoneInfo
* @return String [timezone abbreviation e.g. CET, MST etc.]
*
*/
// public function getTimezoneForPackedTimezoneInfo($_packedTimezoneInfo)
// {
// $offsets = $this->_unpackTimezoneInfo($_packedTimezoneInfo);
// $matchingTimezones = $this->getTimezoneForOffsets($offsets);
// $maxMatches = 0;
// $matchingAbbr = null;
// foreach ($matchingTimezones as $abbr => $timezones) {
// if (count($timezones) > $maxMatches) {
// $maxMatches = count($timezones);
// $matchingAbbr = $abbr;
// }
// }
// return $matchingAbbr;
// }
/**
* Return packed string for given {@param $_timezone}
* @param String $_timezone
* @param String | int | null $_startDate
* @return String
*/
public function encodeTimezone($_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
* @param $_startDate
* @return array
*/
public function getOffsetsForTimezone($_timezone, $_startDate = null)
{
$this->_setStartDate($_startDate);
$cacheId = $this->_getCacheId('offsets', array($_timezone));
if (false === ($offsets = $this->_loadFromCache($cacheId))) {
$offsets = $this->_getOffsetsTemplate();
try {
$timezone = new DateTimeZone($_timezone);
}
catch (Exception $e) {
// $this->_log(__METHOD__, __LINE__, ": could not instantiate timezone {$_timezone}: {$e->getMessage()}");
return null;
}
list($standardTransition, $daylightTransition) = $this->_getTransitionsForTimezoneAndYear($timezone, $this->_startDate['year']);
if ($standardTransition) {
$offsets['bias'] = $standardTransition['offset']/60*-1;
if ($daylightTransition) {
$offsets = $this->_generateOffsetsForTransition($offsets, $standardTransition, 'standard');
$offsets = $this->_generateOffsetsForTransition($offsets, $daylightTransition, 'daylight');
$offsets['standardHour'] += $daylightTransition['offset']/3600;
$offsets['daylightHour'] += $standardTransition['offset']/3600;
//@todo how do we get the standardBias (is usually 0)?
//$offsets['standardBias'] = ...
$offsets['daylightBias'] = ($daylightTransition['offset'] - $standardTransition['offset'])/60*-1;
}
}
$this->_saveInCache($offsets, $cacheId);
}
return $offsets;
}
/**
*
*
* @param array $_offsets
* @param array $_transition
* @param String $_type
* @return array
*/
protected function _generateOffsetsForTransition(Array $_offsets, Array $_transition, $_type)
{
$transitionDateParsed = getdate($_transition['ts']);
$_offsets[$_type . 'Month'] = $transitionDateParsed['mon'];
$_offsets[$_type . 'DayOfWeek'] = $transitionDateParsed['wday'];
$_offsets[$_type . 'Minute'] = $transitionDateParsed['minutes'];
$_offsets[$_type . 'Hour'] = $transitionDateParsed['hours'];
for ($i=5; $i>0; $i--) {
if ($this->_isNthOcurrenceOfWeekdayInMonth($_transition['ts'], $i)) {
$_offsets[$_type . 'Day'] = $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 int $_timestamp
* @param int $_occurence [1 to 5, where 5 indicates the final occurrence during the month if that day of the week does not occur 5 times]
*
* @return bool
*/
protected function _isNthOcurrenceOfWeekdayInMonth($_timestamp, $_occurence)
{
if ($_occurence <= 1) {
return true;
}
$original = new DateTime('@'.$_timestamp);
$orig = $original->format('n');
if ($_occurence == 5) {
$modified = clone($original);
$modified->modify('1 week');
$mod = $modified->format('n');
// modified date is a next month
return $mod > $orig || ($mod == 1 && $orig == 12);
}
$modified = clone($original);
$modified->modify(sprintf('-%d weeks', $_occurence - 1));
$mod = $modified->format('n');
if ($mod != $orig) {
return false;
}
$modified = clone($original);
$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, $_offsets)
{
if (empty($_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'] + ($_offsets['daylightBias'] * -1) ) * 60 * -1;
if ($daylightOffset == $_daylightTransition['offset'] || $daylightOffsetMilestone == $_daylightTransition['offset']) {
$standardParsed = getdate($_standardTransition['ts']);
$daylightParsed = getdate($_daylightTransition['ts']);
if ($standardParsed['mon'] == $_offsets['standardMonth'] &&
$daylightParsed['mon'] == $_offsets['daylightMonth'] &&
$standardParsed['wday'] == $_offsets['standardDayOfWeek'] &&
$daylightParsed['wday'] == $_offsets['daylightDayOfWeek']
) {
return $this->_isNthOcurrenceOfWeekdayInMonth($_daylightTransition['ts'], $_offsets['daylightDay']) &&
$this->_isNthOcurrenceOfWeekdayInMonth($_standardTransition['ts'], $_offsets['standardDay']);
}
}
}
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/vstandardDay/vstandardHour/vstandardMinute/vstandardSecond/vstandardMilliseconds/lstandardBias/a64daylightName/vdaylightYear/vdaylightMonth/vdaylightDayOfWeek/vdaylightDay/vdaylightHour/vdaylightMinute/vdaylightSecond/vdaylightMilliseconds/ldaylightBias';
$timezoneInfo = unpack($timezoneUnpackString, base64_decode($_packedTimezoneInfo));
return $timezoneInfo;
}
/**
* encode timezone info to activesync
*
* @param array $_timezoneInfo
* @return string
*/
protected function _packTimezoneInfo($_timezoneInfo)
{
if (!is_array($_timezoneInfo)) {
return null;
}
$packed = pack(
"la64vvvvvvvvla64vvvvvvvvl",
$_timezoneInfo['bias'],
$_timezoneInfo['standardName'],
$_timezoneInfo['standardYear'],
$_timezoneInfo['standardMonth'],
$_timezoneInfo['standardDayOfWeek'],
$_timezoneInfo['standardDay'],
$_timezoneInfo['standardHour'],
$_timezoneInfo['standardMinute'],
$_timezoneInfo['standardSecond'],
$_timezoneInfo['standardMilliseconds'],
$_timezoneInfo['standardBias'],
$_timezoneInfo['daylightName'],
$_timezoneInfo['daylightYear'],
$_timezoneInfo['daylightMonth'],
$_timezoneInfo['daylightDayOfWeek'],
$_timezoneInfo['daylightDay'],
$_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,
'standardDay' => 0,
'standardHour' => 0,
'standardMinute' => 0,
'standardSecond' => 0,
'standardMilliseconds' => 0,
'standardBias' => 0,
'daylightName' => '',
'daylightYear' => 0,
'daylightMonth' => 0,
'daylightDayOfWeek' => 0,
'daylightDay' => 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($value['standardDay']) || !empty($value['daylightMonth']) || !empty($value['daylightDay'])) &&
(empty($value['standardMonth']) || empty($value['standardDay']) || empty($value['daylightMonth']) || empty($value['daylightDay']))
) {
// 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'] = strftime('%F', $_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)
{
// $this->_log(__METHOD__, __LINE__, 'Checking for matches with timezone: ' . $timezone->getName());
list($standardTransition, $daylightTransition) = $this->_getTransitionsForTimezoneAndYear($timezone, $this->_startDate['year']);
if ($this->_checkTransition($standardTransition, $daylightTransition, $offsets)) {
//$this->_log(__METHOD__, __LINE__, 'Matching timezone ' . $timezone->getName(), 7);
//$this->_log(__METHOD__, __LINE__, 'Matching daylight transition ' . print_r($daylightTransition, 1), 7);
//$this->_log(__METHOD__, __LINE__, 'Matching standard transition ' . print_r($standardTransition, 1), 7);
return $standardTransition;
}
return false;
}
/**
* Returns the standard and daylight transitions for the given {@param $_timezone}
* and {@param $_year}.
*
* @param DateTimeZone $_timezone
* @param $_year
* @return Array
*/
protected function _getTransitionsForTimezoneAndYear(DateTimeZone $_timezone, $_year)
{
$standardTransition = null;
$daylightTransition = null;
if (version_compare(PHP_VERSION, '5.3.0', '>=')) {
// Since php version 5.3.0 getTransitions accepts optional start and end parameters.
$start = mktime(0, 0, 0, 12, 1, $_year - 1);
$end = mktime(24, 0, 0, 12, 31, $_year);
$transitions = $_timezone->getTransitions($start, $end);
} else {
$transitions = $_timezone->getTransitions();
}
$index = 0; //we need to access index counter outside of the foreach loop
$transition = array(); //we need to access the transition counter outside of the foreach loop
foreach ($transitions as $index => $transition) {
if (strftime('%Y', $transition['ts']) == $_year) {
if (isset($transitions[$index+1]) && strftime('%Y', $transitions[$index]['ts']) == strftime('%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, $daylightTransition);
}
protected function _getCacheId($_prefix, $_offsets)
{
return $_prefix . md5(serialize($_offsets));
}
protected function _loadFromCache($key)
{
if ($cache = $this->getCache) {
return $cache->get($key);
}
return false;
}
protected function _saveInCache($value, $key)
{
if ($cache = $this->getCache) {
$cache->set($key, $value);
}
}
/**
* Getter for the cache engine object
*/
protected function getCache()
{
if ($this->cache === null) {
$rcube = rcube::get_instance();
if ($cache = $rcube->config->get('activesync_cache')) {
$ttl = $rcube->config->get('activesync_cache_lifetime', '10d');
$this->cache = $rcube->get_cache('ACTIVESYNC', $cache, $ttl);
}
else {
$this->cache = false;
}
}
return $this->cache;
}
}

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Default Alt Text
kolab_sync_timezone_converter.php (21 KB)

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