nextcloud / server

apps/user_ldap/lib/Group_LDAP.php

Indentation +1039 added lines, -1039 removed lines

@@ -41,1043 +41,1043 @@
 use OC\Cache\CappedMemoryCache;
 
 class Group_LDAP extends BackendUtility implements \OCP\GroupInterface {
-	protected $enabled = false;
-
-	/**
-	 * @var string[] $cachedGroupMembers array of users with gid as key
-	 */
-	protected $cachedGroupMembers;
-
-	/**
-	 * @var string[] $cachedGroupsByMember array of groups with uid as key
-	 */
-	protected $cachedGroupsByMember;
-
-	public function __construct(Access $access) {
-		parent::__construct($access);
-		$filter = $this->access->connection->ldapGroupFilter;
-		$gassoc = $this->access->connection->ldapGroupMemberAssocAttr;
-		if(!empty($filter) && !empty($gassoc)) {
-			$this->enabled = true;
-		}
-
-		$this->cachedGroupMembers = new CappedMemoryCache();
-		$this->cachedGroupsByMember = new CappedMemoryCache();
-	}
-
-	/**
-	 * is user in group?
-	 * @param string $uid uid of the user
-	 * @param string $gid gid of the group
-	 * @return bool
-	 *
-	 * Checks whether the user is member of a group or not.
-	 */
-	public function inGroup($uid, $gid) {
-		if(!$this->enabled) {
-			return false;
-		}
-		$cacheKey = 'inGroup'.$uid.':'.$gid;
-		$inGroup = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($inGroup)) {
-			return (bool)$inGroup;
-		}
-
-		$userDN = $this->access->username2dn($uid);
-
-		if(isset($this->cachedGroupMembers[$gid])) {
-			$isInGroup = in_array($userDN, $this->cachedGroupMembers[$gid]);
-			return $isInGroup;
-		}
-
-		$cacheKeyMembers = 'inGroup-members:'.$gid;
-		$members = $this->access->connection->getFromCache($cacheKeyMembers);
-		if(!is_null($members)) {
-			$this->cachedGroupMembers[$gid] = $members;
-			$isInGroup = in_array($userDN, $members);
-			$this->access->connection->writeToCache($cacheKey, $isInGroup);
-			return $isInGroup;
-		}
-
-		$groupDN = $this->access->groupname2dn($gid);
-		// just in case
-		if(!$groupDN || !$userDN) {
-			$this->access->connection->writeToCache($cacheKey, false);
-			return false;
-		}
-
-		//check primary group first
-		if($gid === $this->getUserPrimaryGroup($userDN)) {
-			$this->access->connection->writeToCache($cacheKey, true);
-			return true;
-		}
-
-		//usually, LDAP attributes are said to be case insensitive. But there are exceptions of course.
-		$members = $this->_groupMembers($groupDN);
-		$members = array_keys($members); // uids are returned as keys
-		if(!is_array($members) || count($members) === 0) {
-			$this->access->connection->writeToCache($cacheKey, false);
-			return false;
-		}
-
-		//extra work if we don't get back user DNs
-		if(strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {
-			$dns = array();
-			$filterParts = array();
-			$bytes = 0;
-			foreach($members as $mid) {
-				$filter = str_replace('%uid', $mid, $this->access->connection->ldapLoginFilter);
-				$filterParts[] = $filter;
-				$bytes += strlen($filter);
-				if($bytes >= 9000000) {
-					// AD has a default input buffer of 10 MB, we do not want
-					// to take even the chance to exceed it
-					$filter = $this->access->combineFilterWithOr($filterParts);
-					$bytes = 0;
-					$filterParts = array();
-					$users = $this->access->fetchListOfUsers($filter, 'dn', count($filterParts));
-					$dns = array_merge($dns, $users);
-				}
-			}
-			if(count($filterParts) > 0) {
-				$filter = $this->access->combineFilterWithOr($filterParts);
-				$users = $this->access->fetchListOfUsers($filter, 'dn', count($filterParts));
-				$dns = array_merge($dns, $users);
-			}
-			$members = $dns;
-		}
-
-		$isInGroup = in_array($userDN, $members);
-		$this->access->connection->writeToCache($cacheKey, $isInGroup);
-		$this->access->connection->writeToCache($cacheKeyMembers, $members);
-		$this->cachedGroupMembers[$gid] = $members;
-
-		return $isInGroup;
-	}
-
-	/**
-	 * @param string $dnGroup
-	 * @return array
-	 *
-	 * For a group that has user membership defined by an LDAP search url attribute returns the users
-	 * that match the search url otherwise returns an empty array.
-	 */
-	public function getDynamicGroupMembers($dnGroup) {
-		$dynamicGroupMemberURL = strtolower($this->access->connection->ldapDynamicGroupMemberURL);
-
-		if (empty($dynamicGroupMemberURL)) {
-			return array();
-		}
-
-		$dynamicMembers = array();
-		$memberURLs = $this->access->readAttribute(
-			$dnGroup,
-			$dynamicGroupMemberURL,
-			$this->access->connection->ldapGroupFilter
-		);
-		if ($memberURLs !== false) {
-			// this group has the 'memberURL' attribute so this is a dynamic group
-			// example 1: ldap:///cn=users,cn=accounts,dc=dcsubbase,dc=dcbase??one?(o=HeadOffice)
-			// example 2: ldap:///cn=users,cn=accounts,dc=dcsubbase,dc=dcbase??one?(&(o=HeadOffice)(uidNumber>=500))
-			$pos = strpos($memberURLs[0], '(');
-			if ($pos !== false) {
-				$memberUrlFilter = substr($memberURLs[0], $pos);
-				$foundMembers = $this->access->searchUsers($memberUrlFilter,'dn');
-				$dynamicMembers = array();
-				foreach($foundMembers as $value) {
-					$dynamicMembers[$value['dn'][0]] = 1;
-				}
-			} else {
-				\OCP\Util::writeLog('user_ldap', 'No search filter found on member url '.
-					'of group ' . $dnGroup, \OCP\Util::DEBUG);
-			}
-		}
-		return $dynamicMembers;
-	}
-
-	/**
-	 * @param string $dnGroup
-	 * @param array|null &$seen
-	 * @return array|mixed|null
-	 */
-	private function _groupMembers($dnGroup, &$seen = null) {
-		if ($seen === null) {
-			$seen = array();
-		}
-		$allMembers = array();
-		if (array_key_exists($dnGroup, $seen)) {
-			// avoid loops
-			return array();
-		}
-		// used extensively in cron job, caching makes sense for nested groups
-		$cacheKey = '_groupMembers'.$dnGroup;
-		$groupMembers = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupMembers)) {
-			return $groupMembers;
-		}
-		$seen[$dnGroup] = 1;
-		$members = $this->access->readAttribute($dnGroup, $this->access->connection->ldapGroupMemberAssocAttr,
-												$this->access->connection->ldapGroupFilter);
-		if (is_array($members)) {
-			foreach ($members as $memberDN) {
-				$allMembers[$memberDN] = 1;
-				$nestedGroups = $this->access->connection->ldapNestedGroups;
-				if (!empty($nestedGroups)) {
-					$subMembers = $this->_groupMembers($memberDN, $seen);
-					if ($subMembers) {
-						$allMembers = array_merge($allMembers, $subMembers);
-					}
-				}
-			}
-		}
-
-		$allMembers = array_merge($allMembers, $this->getDynamicGroupMembers($dnGroup));
-
-		$this->access->connection->writeToCache($cacheKey, $allMembers);
-		return $allMembers;
-	}
-
-	/**
-	 * @param string $DN
-	 * @param array|null &$seen
-	 * @return array
-	 */
-	private function _getGroupDNsFromMemberOf($DN, &$seen = null) {
-		if ($seen === null) {
-			$seen = array();
-		}
-		if (array_key_exists($DN, $seen)) {
-			// avoid loops
-			return array();
-		}
-		$seen[$DN] = 1;
-		$groups = $this->access->readAttribute($DN, 'memberOf');
-		if (!is_array($groups)) {
-			return array();
-		}
-		$groups = $this->access->groupsMatchFilter($groups);
-		$allGroups =  $groups;
-		$nestedGroups = $this->access->connection->ldapNestedGroups;
-		if (intval($nestedGroups) === 1) {
-			foreach ($groups as $group) {
-				$subGroups = $this->_getGroupDNsFromMemberOf($group, $seen);
-				$allGroups = array_merge($allGroups, $subGroups);
-			}
-		}
-		return $allGroups;
-	}
-
-	/**
-	 * translates a gidNumber into an ownCloud internal name
-	 * @param string $gid as given by gidNumber on POSIX LDAP
-	 * @param string $dn a DN that belongs to the same domain as the group
-	 * @return string|bool
-	 */
-	public function gidNumber2Name($gid, $dn) {
-		$cacheKey = 'gidNumberToName' . $gid;
-		$groupName = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupName) && isset($groupName)) {
-			return $groupName;
-		}
-
-		//we need to get the DN from LDAP
-		$filter = $this->access->combineFilterWithAnd([
-			$this->access->connection->ldapGroupFilter,
-			'objectClass=posixGroup',
-			$this->access->connection->ldapGidNumber . '=' . $gid
-		]);
-		$result = $this->access->searchGroups($filter, array('dn'), 1);
-		if(empty($result)) {
-			return false;
-		}
-		$dn = $result[0]['dn'][0];
-
-		//and now the group name
-		//NOTE once we have separate ownCloud group IDs and group names we can
-		//directly read the display name attribute instead of the DN
-		$name = $this->access->dn2groupname($dn);
-
-		$this->access->connection->writeToCache($cacheKey, $name);
-
-		return $name;
-	}
-
-	/**
-	 * returns the entry's gidNumber
-	 * @param string $dn
-	 * @param string $attribute
-	 * @return string|bool
-	 */
-	private function getEntryGidNumber($dn, $attribute) {
-		$value = $this->access->readAttribute($dn, $attribute);
-		if(is_array($value) && !empty($value)) {
-			return $value[0];
-		}
-		return false;
-	}
-
-	/**
-	 * returns the group's primary ID
-	 * @param string $dn
-	 * @return string|bool
-	 */
-	public function getGroupGidNumber($dn) {
-		return $this->getEntryGidNumber($dn, 'gidNumber');
-	}
-
-	/**
-	 * returns the user's gidNumber
-	 * @param string $dn
-	 * @return string|bool
-	 */
-	public function getUserGidNumber($dn) {
-		$gidNumber = false;
-		if($this->access->connection->hasGidNumber) {
-			$gidNumber = $this->getEntryGidNumber($dn, $this->access->connection->ldapGidNumber);
-			if($gidNumber === false) {
-				$this->access->connection->hasGidNumber = false;
-			}
-		}
-		return $gidNumber;
-	}
-
-	/**
-	 * returns a filter for a "users has specific gid" search or count operation
-	 *
-	 * @param string $groupDN
-	 * @param string $search
-	 * @return string
-	 * @throws \Exception
-	 */
-	private function prepareFilterForUsersHasGidNumber($groupDN, $search = '') {
-		$groupID = $this->getGroupGidNumber($groupDN);
-		if($groupID === false) {
-			throw new \Exception('Not a valid group');
-		}
-
-		$filterParts = [];
-		$filterParts[] = $this->access->getFilterForUserCount();
-		if ($search !== '') {
-			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
-		}
-		$filterParts[] = $this->access->connection->ldapGidNumber .'=' . $groupID;
-
-		$filter = $this->access->combineFilterWithAnd($filterParts);
-
-		return $filter;
-	}
-
-	/**
-	 * returns a list of users that have the given group as gid number
-	 *
-	 * @param string $groupDN
-	 * @param string $search
-	 * @param int $limit
-	 * @param int $offset
-	 * @return string[]
-	 */
-	public function getUsersInGidNumber($groupDN, $search = '', $limit = -1, $offset = 0) {
-		try {
-			$filter = $this->prepareFilterForUsersHasGidNumber($groupDN, $search);
-			$users = $this->access->fetchListOfUsers(
-				$filter,
-				[$this->access->connection->ldapUserDisplayName, 'dn'],
-				$limit,
-				$offset
-			);
-			return $this->access->nextcloudUserNames($users);
-		} catch (\Exception $e) {
-			return [];
-		}
-	}
-
-	/**
-	 * returns the number of users that have the given group as gid number
-	 *
-	 * @param string $groupDN
-	 * @param string $search
-	 * @param int $limit
-	 * @param int $offset
-	 * @return int
-	 */
-	public function countUsersInGidNumber($groupDN, $search = '', $limit = -1, $offset = 0) {
-		try {
-			$filter = $this->prepareFilterForUsersHasGidNumber($groupDN, $search);
-			$users = $this->access->countUsers($filter, ['dn'], $limit, $offset);
-			return (int)$users;
-		} catch (\Exception $e) {
-			return 0;
-		}
-	}
-
-	/**
-	 * gets the gidNumber of a user
-	 * @param string $dn
-	 * @return string
-	 */
-	public function getUserGroupByGid($dn) {
-		$groupID = $this->getUserGidNumber($dn);
-		if($groupID !== false) {
-			$groupName = $this->gidNumber2Name($groupID, $dn);
-			if($groupName !== false) {
-				return $groupName;
-			}
-		}
-
-		return false;
-	}
-
-	/**
-	 * translates a primary group ID into an Nextcloud internal name
-	 * @param string $gid as given by primaryGroupID on AD
-	 * @param string $dn a DN that belongs to the same domain as the group
-	 * @return string|bool
-	 */
-	public function primaryGroupID2Name($gid, $dn) {
-		$cacheKey = 'primaryGroupIDtoName';
-		$groupNames = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupNames) && isset($groupNames[$gid])) {
-			return $groupNames[$gid];
-		}
-
-		$domainObjectSid = $this->access->getSID($dn);
-		if($domainObjectSid === false) {
-			return false;
-		}
-
-		//we need to get the DN from LDAP
-		$filter = $this->access->combineFilterWithAnd(array(
-			$this->access->connection->ldapGroupFilter,
-			'objectsid=' . $domainObjectSid . '-' . $gid
-		));
-		$result = $this->access->searchGroups($filter, array('dn'), 1);
-		if(empty($result)) {
-			return false;
-		}
-		$dn = $result[0]['dn'][0];
-
-		//and now the group name
-		//NOTE once we have separate Nextcloud group IDs and group names we can
-		//directly read the display name attribute instead of the DN
-		$name = $this->access->dn2groupname($dn);
-
-		$this->access->connection->writeToCache($cacheKey, $name);
-
-		return $name;
-	}
-
-	/**
-	 * returns the entry's primary group ID
-	 * @param string $dn
-	 * @param string $attribute
-	 * @return string|bool
-	 */
-	private function getEntryGroupID($dn, $attribute) {
-		$value = $this->access->readAttribute($dn, $attribute);
-		if(is_array($value) && !empty($value)) {
-			return $value[0];
-		}
-		return false;
-	}
-
-	/**
-	 * returns the group's primary ID
-	 * @param string $dn
-	 * @return string|bool
-	 */
-	public function getGroupPrimaryGroupID($dn) {
-		return $this->getEntryGroupID($dn, 'primaryGroupToken');
-	}
-
-	/**
-	 * returns the user's primary group ID
-	 * @param string $dn
-	 * @return string|bool
-	 */
-	public function getUserPrimaryGroupIDs($dn) {
-		$primaryGroupID = false;
-		if($this->access->connection->hasPrimaryGroups) {
-			$primaryGroupID = $this->getEntryGroupID($dn, 'primaryGroupID');
-			if($primaryGroupID === false) {
-				$this->access->connection->hasPrimaryGroups = false;
-			}
-		}
-		return $primaryGroupID;
-	}
-
-	/**
-	 * returns a filter for a "users in primary group" search or count operation
-	 *
-	 * @param string $groupDN
-	 * @param string $search
-	 * @return string
-	 * @throws \Exception
-	 */
-	private function prepareFilterForUsersInPrimaryGroup($groupDN, $search = '') {
-		$groupID = $this->getGroupPrimaryGroupID($groupDN);
-		if($groupID === false) {
-			throw new \Exception('Not a valid group');
-		}
-
-		$filterParts = [];
-		$filterParts[] = $this->access->getFilterForUserCount();
-		if ($search !== '') {
-			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
-		}
-		$filterParts[] = 'primaryGroupID=' . $groupID;
-
-		$filter = $this->access->combineFilterWithAnd($filterParts);
-
-		return $filter;
-	}
-
-	/**
-	 * returns a list of users that have the given group as primary group
-	 *
-	 * @param string $groupDN
-	 * @param string $search
-	 * @param int $limit
-	 * @param int $offset
-	 * @return string[]
-	 */
-	public function getUsersInPrimaryGroup($groupDN, $search = '', $limit = -1, $offset = 0) {
-		try {
-			$filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
-			$users = $this->access->fetchListOfUsers(
-				$filter,
-				array($this->access->connection->ldapUserDisplayName, 'dn'),
-				$limit,
-				$offset
-			);
-			return $this->access->nextcloudUserNames($users);
-		} catch (\Exception $e) {
-			return array();
-		}
-	}
-
-	/**
-	 * returns the number of users that have the given group as primary group
-	 *
-	 * @param string $groupDN
-	 * @param string $search
-	 * @param int $limit
-	 * @param int $offset
-	 * @return int
-	 */
-	public function countUsersInPrimaryGroup($groupDN, $search = '', $limit = -1, $offset = 0) {
-		try {
-			$filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
-			$users = $this->access->countUsers($filter, array('dn'), $limit, $offset);
-			return (int)$users;
-		} catch (\Exception $e) {
-			return 0;
-		}
-	}
-
-	/**
-	 * gets the primary group of a user
-	 * @param string $dn
-	 * @return string
-	 */
-	public function getUserPrimaryGroup($dn) {
-		$groupID = $this->getUserPrimaryGroupIDs($dn);
-		if($groupID !== false) {
-			$groupName = $this->primaryGroupID2Name($groupID, $dn);
-			if($groupName !== false) {
-				return $groupName;
-			}
-		}
-
-		return false;
-	}
-
-	/**
-	 * Get all groups a user belongs to
-	 * @param string $uid Name of the user
-	 * @return array with group names
-	 *
-	 * This function fetches all groups a user belongs to. It does not check
-	 * if the user exists at all.
-	 *
-	 * This function includes groups based on dynamic group membership.
-	 */
-	public function getUserGroups($uid) {
-		if(!$this->enabled) {
-			return array();
-		}
-		$cacheKey = 'getUserGroups'.$uid;
-		$userGroups = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($userGroups)) {
-			return $userGroups;
-		}
-		$userDN = $this->access->username2dn($uid);
-		if(!$userDN) {
-			$this->access->connection->writeToCache($cacheKey, array());
-			return array();
-		}
-
-		$groups = [];
-		$primaryGroup = $this->getUserPrimaryGroup($userDN);
-		$gidGroupName = $this->getUserGroupByGid($userDN);
-
-		$dynamicGroupMemberURL = strtolower($this->access->connection->ldapDynamicGroupMemberURL);
-
-		if (!empty($dynamicGroupMemberURL)) {
-			// look through dynamic groups to add them to the result array if needed
-			$groupsToMatch = $this->access->fetchListOfGroups(
-				$this->access->connection->ldapGroupFilter,array('dn',$dynamicGroupMemberURL));
-			foreach($groupsToMatch as $dynamicGroup) {
-				if (!array_key_exists($dynamicGroupMemberURL, $dynamicGroup)) {
-					continue;
-				}
-				$pos = strpos($dynamicGroup[$dynamicGroupMemberURL][0], '(');
-				if ($pos !== false) {
-					$memberUrlFilter = substr($dynamicGroup[$dynamicGroupMemberURL][0],$pos);
-					// apply filter via ldap search to see if this user is in this
-					// dynamic group
-					$userMatch = $this->access->readAttribute(
-						$userDN,
-						$this->access->connection->ldapUserDisplayName,
-						$memberUrlFilter
-					);
-					if ($userMatch !== false) {
-						// match found so this user is in this group
-						$groupName = $this->access->dn2groupname($dynamicGroup['dn'][0]);
-						if(is_string($groupName)) {
-							// be sure to never return false if the dn could not be
-							// resolved to a name, for whatever reason.
-							$groups[] = $groupName;
-						}
-					}
-				} else {
-					\OCP\Util::writeLog('user_ldap', 'No search filter found on member url '.
-						'of group ' . print_r($dynamicGroup, true), \OCP\Util::DEBUG);
-				}
-			}
-		}
-
-		// if possible, read out membership via memberOf. It's far faster than
-		// performing a search, which still is a fallback later.
-		// memberof doesn't support memberuid, so skip it here.
-		if(intval($this->access->connection->hasMemberOfFilterSupport) === 1
-			&& intval($this->access->connection->useMemberOfToDetectMembership) === 1
-		    && strtolower($this->access->connection->ldapGroupMemberAssocAttr) !== 'memberuid'
-		    ) {
-			$groupDNs = $this->_getGroupDNsFromMemberOf($userDN);
-			if (is_array($groupDNs)) {
-				foreach ($groupDNs as $dn) {
-					$groupName = $this->access->dn2groupname($dn);
-					if(is_string($groupName)) {
-						// be sure to never return false if the dn could not be
-						// resolved to a name, for whatever reason.
-						$groups[] = $groupName;
-					}
-				}
-			}
-
-			if($primaryGroup !== false) {
-				$groups[] = $primaryGroup;
-			}
-			if($gidGroupName !== false) {
-				$groups[] = $gidGroupName;
-			}
-			$this->access->connection->writeToCache($cacheKey, $groups);
-			return $groups;
-		}
-
-		//uniqueMember takes DN, memberuid the uid, so we need to distinguish
-		if((strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'uniquemember')
-			|| (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'member')
-		) {
-			$uid = $userDN;
-		} else if(strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {
-			$result = $this->access->readAttribute($userDN, 'uid');
-			if ($result === false) {
-				\OCP\Util::writeLog('user_ldap', 'No uid attribute found for DN ' . $userDN . ' on '.
-					$this->access->connection->ldapHost, \OCP\Util::DEBUG);
-			}
-			$uid = $result[0];
-		} else {
-			// just in case
-			$uid = $userDN;
-		}
-
-		if(isset($this->cachedGroupsByMember[$uid])) {
-			$groups = array_merge($groups, $this->cachedGroupsByMember[$uid]);
-		} else {
-			$groupsByMember = array_values($this->getGroupsByMember($uid));
-			$groupsByMember = $this->access->nextcloudGroupNames($groupsByMember);
-			$this->cachedGroupsByMember[$uid] = $groupsByMember;
-			$groups = array_merge($groups, $groupsByMember);
-		}
-
-		if($primaryGroup !== false) {
-			$groups[] = $primaryGroup;
-		}
-		if($gidGroupName !== false) {
-			$groups[] = $gidGroupName;
-		}
-
-		$groups = array_unique($groups, SORT_LOCALE_STRING);
-		$this->access->connection->writeToCache($cacheKey, $groups);
-
-		return $groups;
-	}
-
-	/**
-	 * @param string $dn
-	 * @param array|null &$seen
-	 * @return array
-	 */
-	private function getGroupsByMember($dn, &$seen = null) {
-		if ($seen === null) {
-			$seen = array();
-		}
-		$allGroups = array();
-		if (array_key_exists($dn, $seen)) {
-			// avoid loops
-			return array();
-		}
-		$seen[$dn] = true;
-		$filter = $this->access->combineFilterWithAnd(array(
-			$this->access->connection->ldapGroupFilter,
-			$this->access->connection->ldapGroupMemberAssocAttr.'='.$dn
-		));
-		$groups = $this->access->fetchListOfGroups($filter,
-			array($this->access->connection->ldapGroupDisplayName, 'dn'));
-		if (is_array($groups)) {
-			foreach ($groups as $groupobj) {
-				$groupDN = $groupobj['dn'][0];
-				$allGroups[$groupDN] = $groupobj;
-				$nestedGroups = $this->access->connection->ldapNestedGroups;
-				if (!empty($nestedGroups)) {
-					$supergroups = $this->getGroupsByMember($groupDN, $seen);
-					if (is_array($supergroups) && (count($supergroups)>0)) {
-						$allGroups = array_merge($allGroups, $supergroups);
-					}
-				}
-			}
-		}
-		return $allGroups;
-	}
-
-	/**
-	 * get a list of all users in a group
-	 *
-	 * @param string $gid
-	 * @param string $search
-	 * @param int $limit
-	 * @param int $offset
-	 * @return array with user ids
-	 */
-	public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
-		if(!$this->enabled) {
-			return array();
-		}
-		if(!$this->groupExists($gid)) {
-			return array();
-		}
-		$search = $this->access->escapeFilterPart($search, true);
-		$cacheKey = 'usersInGroup-'.$gid.'-'.$search.'-'.$limit.'-'.$offset;
-		// check for cache of the exact query
-		$groupUsers = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupUsers)) {
-			return $groupUsers;
-		}
-
-		// check for cache of the query without limit and offset
-		$groupUsers = $this->access->connection->getFromCache('usersInGroup-'.$gid.'-'.$search);
-		if(!is_null($groupUsers)) {
-			$groupUsers = array_slice($groupUsers, $offset, $limit);
-			$this->access->connection->writeToCache($cacheKey, $groupUsers);
-			return $groupUsers;
-		}
-
-		if($limit === -1) {
-			$limit = null;
-		}
-		$groupDN = $this->access->groupname2dn($gid);
-		if(!$groupDN) {
-			// group couldn't be found, return empty resultset
-			$this->access->connection->writeToCache($cacheKey, array());
-			return array();
-		}
-
-		$primaryUsers = $this->getUsersInPrimaryGroup($groupDN, $search, $limit, $offset);
-		$posixGroupUsers = $this->getUsersInGidNumber($groupDN, $search, $limit, $offset);
-		$members = array_keys($this->_groupMembers($groupDN));
-		if(!$members && empty($posixGroupUsers) && empty($primaryUsers)) {
-			//in case users could not be retrieved, return empty result set
-			$this->access->connection->writeToCache($cacheKey, []);
-			return [];
-		}
-
-		$groupUsers = array();
-		$isMemberUid = (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid');
-		$attrs = $this->access->userManager->getAttributes(true);
-		foreach($members as $member) {
-			if($isMemberUid) {
-				//we got uids, need to get their DNs to 'translate' them to user names
-				$filter = $this->access->combineFilterWithAnd(array(
-					str_replace('%uid', $member, $this->access->connection->ldapLoginFilter),
-					$this->access->getFilterPartForUserSearch($search)
-				));
-				$ldap_users = $this->access->fetchListOfUsers($filter, $attrs, 1);
-				if(count($ldap_users) < 1) {
-					continue;
-				}
-				$groupUsers[] = $this->access->dn2username($ldap_users[0]['dn'][0]);
-			} else {
-				//we got DNs, check if we need to filter by search or we can give back all of them
-				if ($search !== '') {
-					if(!$this->access->readAttribute($member,
-						$this->access->connection->ldapUserDisplayName,
-						$this->access->getFilterPartForUserSearch($search))) {
-						continue;
-					}
-				}
-				// dn2username will also check if the users belong to the allowed base
-				if($ocname = $this->access->dn2username($member)) {
-					$groupUsers[] = $ocname;
-				}
-			}
-		}
-
-		$groupUsers = array_unique(array_merge($groupUsers, $primaryUsers, $posixGroupUsers));
-		natsort($groupUsers);
-		$this->access->connection->writeToCache('usersInGroup-'.$gid.'-'.$search, $groupUsers);
-		$groupUsers = array_slice($groupUsers, $offset, $limit);
-
-		$this->access->connection->writeToCache($cacheKey, $groupUsers);
-
-		return $groupUsers;
-	}
-
-	/**
-	 * returns the number of users in a group, who match the search term
-	 * @param string $gid the internal group name
-	 * @param string $search optional, a search string
-	 * @return int|bool
-	 */
-	public function countUsersInGroup($gid, $search = '') {
-		$cacheKey = 'countUsersInGroup-'.$gid.'-'.$search;
-		if(!$this->enabled || !$this->groupExists($gid)) {
-			return false;
-		}
-		$groupUsers = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupUsers)) {
-			return $groupUsers;
-		}
-
-		$groupDN = $this->access->groupname2dn($gid);
-		if(!$groupDN) {
-			// group couldn't be found, return empty result set
-			$this->access->connection->writeToCache($cacheKey, false);
-			return false;
-		}
-
-		$members = array_keys($this->_groupMembers($groupDN));
-		$primaryUserCount = $this->countUsersInPrimaryGroup($groupDN, '');
-		if(!$members && $primaryUserCount === 0) {
-			//in case users could not be retrieved, return empty result set
-			$this->access->connection->writeToCache($cacheKey, false);
-			return false;
-		}
-
-		if ($search === '') {
-			$groupUsers = count($members) + $primaryUserCount;
-			$this->access->connection->writeToCache($cacheKey, $groupUsers);
-			return $groupUsers;
-		}
-		$search = $this->access->escapeFilterPart($search, true);
-		$isMemberUid =
-			(strtolower($this->access->connection->ldapGroupMemberAssocAttr)
-			=== 'memberuid');
-
-		//we need to apply the search filter
-		//alternatives that need to be checked:
-		//a) get all users by search filter and array_intersect them
-		//b) a, but only when less than 1k 10k ?k users like it is
-		//c) put all DNs|uids in a LDAP filter, combine with the search string
-		//   and let it count.
-		//For now this is not important, because the only use of this method
-		//does not supply a search string
-		$groupUsers = array();
-		foreach($members as $member) {
-			if($isMemberUid) {
-				//we got uids, need to get their DNs to 'translate' them to user names
-				$filter = $this->access->combineFilterWithAnd(array(
-					str_replace('%uid', $member, $this->access->connection->ldapLoginFilter),
-					$this->access->getFilterPartForUserSearch($search)
-				));
-				$ldap_users = $this->access->fetchListOfUsers($filter, 'dn', 1);
-				if(count($ldap_users) < 1) {
-					continue;
-				}
-				$groupUsers[] = $this->access->dn2username($ldap_users[0]);
-			} else {
-				//we need to apply the search filter now
-				if(!$this->access->readAttribute($member,
-					$this->access->connection->ldapUserDisplayName,
-					$this->access->getFilterPartForUserSearch($search))) {
-					continue;
-				}
-				// dn2username will also check if the users belong to the allowed base
-				if($ocname = $this->access->dn2username($member)) {
-					$groupUsers[] = $ocname;
-				}
-			}
-		}
-
-		//and get users that have the group as primary
-		$primaryUsers = $this->countUsersInPrimaryGroup($groupDN, $search);
-
-		return count($groupUsers) + $primaryUsers;
-	}
-
-	/**
-	 * get a list of all groups
-	 *
-	 * @param string $search
-	 * @param $limit
-	 * @param int $offset
-	 * @return array with group names
-	 *
-	 * Returns a list with all groups (used by getGroups)
-	 */
-	protected function getGroupsChunk($search = '', $limit = -1, $offset = 0) {
-		if(!$this->enabled) {
-			return array();
-		}
-		$cacheKey = 'getGroups-'.$search.'-'.$limit.'-'.$offset;
-
-		//Check cache before driving unnecessary searches
-		\OCP\Util::writeLog('user_ldap', 'getGroups '.$cacheKey, \OCP\Util::DEBUG);
-		$ldap_groups = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($ldap_groups)) {
-			return $ldap_groups;
-		}
-
-		// if we'd pass -1 to LDAP search, we'd end up in a Protocol
-		// error. With a limit of 0, we get 0 results. So we pass null.
-		if($limit <= 0) {
-			$limit = null;
-		}
-		$filter = $this->access->combineFilterWithAnd(array(
-			$this->access->connection->ldapGroupFilter,
-			$this->access->getFilterPartForGroupSearch($search)
-		));
-		\OCP\Util::writeLog('user_ldap', 'getGroups Filter '.$filter, \OCP\Util::DEBUG);
-		$ldap_groups = $this->access->fetchListOfGroups($filter,
-				array($this->access->connection->ldapGroupDisplayName, 'dn'),
-				$limit,
-				$offset);
-		$ldap_groups = $this->access->nextcloudGroupNames($ldap_groups);
-
-		$this->access->connection->writeToCache($cacheKey, $ldap_groups);
-		return $ldap_groups;
-	}
-
-	/**
-	 * get a list of all groups using a paged search
-	 *
-	 * @param string $search
-	 * @param int $limit
-	 * @param int $offset
-	 * @return array with group names
-	 *
-	 * Returns a list with all groups
-	 * Uses a paged search if available to override a
-	 * server side search limit.
-	 * (active directory has a limit of 1000 by default)
-	 */
-	public function getGroups($search = '', $limit = -1, $offset = 0) {
-		if(!$this->enabled) {
-			return array();
-		}
-		$search = $this->access->escapeFilterPart($search, true);
-		$pagingSize = intval($this->access->connection->ldapPagingSize);
-		if (!$this->access->connection->hasPagedResultSupport || $pagingSize <= 0) {
-			return $this->getGroupsChunk($search, $limit, $offset);
-		}
-		$maxGroups = 100000; // limit max results (just for safety reasons)
-		if ($limit > -1) {
-		   $overallLimit = min($limit + $offset, $maxGroups);
-		} else {
-		   $overallLimit = $maxGroups;
-		}
-		$chunkOffset = $offset;
-		$allGroups = array();
-		while ($chunkOffset < $overallLimit) {
-			$chunkLimit = min($pagingSize, $overallLimit - $chunkOffset);
-			$ldapGroups = $this->getGroupsChunk($search, $chunkLimit, $chunkOffset);
-			$nread = count($ldapGroups);
-			\OCP\Util::writeLog('user_ldap', 'getGroups('.$search.'): read '.$nread.' at offset '.$chunkOffset.' (limit: '.$chunkLimit.')', \OCP\Util::DEBUG);
-			if ($nread) {
-				$allGroups = array_merge($allGroups, $ldapGroups);
-				$chunkOffset += $nread;
-			}
-			if ($nread < $chunkLimit) {
-				break;
-			}
-		}
-		return $allGroups;
-	}
-
-	/**
-	 * @param string $group
-	 * @return bool
-	 */
-	public function groupMatchesFilter($group) {
-		return (strripos($group, $this->groupSearch) !== false);
-	}
-
-	/**
-	 * check if a group exists
-	 * @param string $gid
-	 * @return bool
-	 */
-	public function groupExists($gid) {
-		$groupExists = $this->access->connection->getFromCache('groupExists'.$gid);
-		if(!is_null($groupExists)) {
-			return (bool)$groupExists;
-		}
-
-		//getting dn, if false the group does not exist. If dn, it may be mapped
-		//only, requires more checking.
-		$dn = $this->access->groupname2dn($gid);
-		if(!$dn) {
-			$this->access->connection->writeToCache('groupExists'.$gid, false);
-			return false;
-		}
-
-		//if group really still exists, we will be able to read its objectclass
-		if(!is_array($this->access->readAttribute($dn, ''))) {
-			$this->access->connection->writeToCache('groupExists'.$gid, false);
-			return false;
-		}
-
-		$this->access->connection->writeToCache('groupExists'.$gid, true);
-		return true;
-	}
-
-	/**
-	* Check if backend implements actions
-	* @param int $actions bitwise-or'ed actions
-	* @return boolean
-	*
-	* Returns the supported actions as int to be
-	* compared with \OC\User\Backend::CREATE_USER etc.
-	*/
-	public function implementsActions($actions) {
-		return (bool)(\OC\Group\Backend::COUNT_USERS & $actions);
-	}
-
-	/**
-	 * Return access for LDAP interaction.
-	 * @return Access instance of Access for LDAP interaction
-	 */
-	public function getLDAPAccess() {
-		return $this->access;
-	}
+    protected $enabled = false;
+
+    /**
+     * @var string[] $cachedGroupMembers array of users with gid as key
+     */
+    protected $cachedGroupMembers;
+
+    /**
+     * @var string[] $cachedGroupsByMember array of groups with uid as key
+     */
+    protected $cachedGroupsByMember;
+
+    public function __construct(Access $access) {
+        parent::__construct($access);
+        $filter = $this->access->connection->ldapGroupFilter;
+        $gassoc = $this->access->connection->ldapGroupMemberAssocAttr;
+        if(!empty($filter) && !empty($gassoc)) {
+            $this->enabled = true;
+        }
+
+        $this->cachedGroupMembers = new CappedMemoryCache();
+        $this->cachedGroupsByMember = new CappedMemoryCache();
+    }
+
+    /**
+     * is user in group?
+     * @param string $uid uid of the user
+     * @param string $gid gid of the group
+     * @return bool
+     *
+     * Checks whether the user is member of a group or not.
+     */
+    public function inGroup($uid, $gid) {
+        if(!$this->enabled) {
+            return false;
+        }
+        $cacheKey = 'inGroup'.$uid.':'.$gid;
+        $inGroup = $this->access->connection->getFromCache($cacheKey);
+        if(!is_null($inGroup)) {
+            return (bool)$inGroup;
+        }
+
+        $userDN = $this->access->username2dn($uid);
+
+        if(isset($this->cachedGroupMembers[$gid])) {
+            $isInGroup = in_array($userDN, $this->cachedGroupMembers[$gid]);
+            return $isInGroup;
+        }
+
+        $cacheKeyMembers = 'inGroup-members:'.$gid;
+        $members = $this->access->connection->getFromCache($cacheKeyMembers);
+        if(!is_null($members)) {
+            $this->cachedGroupMembers[$gid] = $members;
+            $isInGroup = in_array($userDN, $members);
+            $this->access->connection->writeToCache($cacheKey, $isInGroup);
+            return $isInGroup;
+        }
+
+        $groupDN = $this->access->groupname2dn($gid);
+        // just in case
+        if(!$groupDN || !$userDN) {
+            $this->access->connection->writeToCache($cacheKey, false);
+            return false;
+        }
+
+        //check primary group first
+        if($gid === $this->getUserPrimaryGroup($userDN)) {
+            $this->access->connection->writeToCache($cacheKey, true);
+            return true;
+        }
+
+        //usually, LDAP attributes are said to be case insensitive. But there are exceptions of course.
+        $members = $this->_groupMembers($groupDN);
+        $members = array_keys($members); // uids are returned as keys
+        if(!is_array($members) || count($members) === 0) {
+            $this->access->connection->writeToCache($cacheKey, false);
+            return false;
+        }
+
+        //extra work if we don't get back user DNs
+        if(strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {
+            $dns = array();
+            $filterParts = array();
+            $bytes = 0;
+            foreach($members as $mid) {
+                $filter = str_replace('%uid', $mid, $this->access->connection->ldapLoginFilter);
+                $filterParts[] = $filter;
+                $bytes += strlen($filter);
+                if($bytes >= 9000000) {
+                    // AD has a default input buffer of 10 MB, we do not want
+                    // to take even the chance to exceed it
+                    $filter = $this->access->combineFilterWithOr($filterParts);
+                    $bytes = 0;
+                    $filterParts = array();
+                    $users = $this->access->fetchListOfUsers($filter, 'dn', count($filterParts));
+                    $dns = array_merge($dns, $users);
+                }
+            }
+            if(count($filterParts) > 0) {
+                $filter = $this->access->combineFilterWithOr($filterParts);
+                $users = $this->access->fetchListOfUsers($filter, 'dn', count($filterParts));
+                $dns = array_merge($dns, $users);
+            }
+            $members = $dns;
+        }
+
+        $isInGroup = in_array($userDN, $members);
+        $this->access->connection->writeToCache($cacheKey, $isInGroup);
+        $this->access->connection->writeToCache($cacheKeyMembers, $members);
+        $this->cachedGroupMembers[$gid] = $members;
+
+        return $isInGroup;
+    }
+
+    /**
+     * @param string $dnGroup
+     * @return array
+     *
+     * For a group that has user membership defined by an LDAP search url attribute returns the users
+     * that match the search url otherwise returns an empty array.
+     */
+    public function getDynamicGroupMembers($dnGroup) {
+        $dynamicGroupMemberURL = strtolower($this->access->connection->ldapDynamicGroupMemberURL);
+
+        if (empty($dynamicGroupMemberURL)) {
+            return array();
+        }
+
+        $dynamicMembers = array();
+        $memberURLs = $this->access->readAttribute(
+            $dnGroup,
+            $dynamicGroupMemberURL,
+            $this->access->connection->ldapGroupFilter
+        );
+        if ($memberURLs !== false) {
+            // this group has the 'memberURL' attribute so this is a dynamic group
+            // example 1: ldap:///cn=users,cn=accounts,dc=dcsubbase,dc=dcbase??one?(o=HeadOffice)
+            // example 2: ldap:///cn=users,cn=accounts,dc=dcsubbase,dc=dcbase??one?(&(o=HeadOffice)(uidNumber>=500))
+            $pos = strpos($memberURLs[0], '(');
+            if ($pos !== false) {
+                $memberUrlFilter = substr($memberURLs[0], $pos);
+                $foundMembers = $this->access->searchUsers($memberUrlFilter,'dn');
+                $dynamicMembers = array();
+                foreach($foundMembers as $value) {
+                    $dynamicMembers[$value['dn'][0]] = 1;
+                }
+            } else {
+                \OCP\Util::writeLog('user_ldap', 'No search filter found on member url '.
+                    'of group ' . $dnGroup, \OCP\Util::DEBUG);
+            }
+        }
+        return $dynamicMembers;
+    }
+
+    /**
+     * @param string $dnGroup
+     * @param array|null &$seen
+     * @return array|mixed|null
+     */
+    private function _groupMembers($dnGroup, &$seen = null) {
+        if ($seen === null) {
+            $seen = array();
+        }
+        $allMembers = array();
+        if (array_key_exists($dnGroup, $seen)) {
+            // avoid loops
+            return array();
+        }
+        // used extensively in cron job, caching makes sense for nested groups
+        $cacheKey = '_groupMembers'.$dnGroup;
+        $groupMembers = $this->access->connection->getFromCache($cacheKey);
+        if(!is_null($groupMembers)) {
+            return $groupMembers;
+        }
+        $seen[$dnGroup] = 1;
+        $members = $this->access->readAttribute($dnGroup, $this->access->connection->ldapGroupMemberAssocAttr,
+                                                $this->access->connection->ldapGroupFilter);
+        if (is_array($members)) {
+            foreach ($members as $memberDN) {
+                $allMembers[$memberDN] = 1;
+                $nestedGroups = $this->access->connection->ldapNestedGroups;
+                if (!empty($nestedGroups)) {
+                    $subMembers = $this->_groupMembers($memberDN, $seen);
+                    if ($subMembers) {
+                        $allMembers = array_merge($allMembers, $subMembers);
+                    }
+                }
+            }
+        }
+
+        $allMembers = array_merge($allMembers, $this->getDynamicGroupMembers($dnGroup));
+
+        $this->access->connection->writeToCache($cacheKey, $allMembers);
+        return $allMembers;
+    }
+
+    /**
+     * @param string $DN
+     * @param array|null &$seen
+     * @return array
+     */
+    private function _getGroupDNsFromMemberOf($DN, &$seen = null) {
+        if ($seen === null) {
+            $seen = array();
+        }
+        if (array_key_exists($DN, $seen)) {
+            // avoid loops
+            return array();
+        }
+        $seen[$DN] = 1;
+        $groups = $this->access->readAttribute($DN, 'memberOf');
+        if (!is_array($groups)) {
+            return array();
+        }
+        $groups = $this->access->groupsMatchFilter($groups);
+        $allGroups =  $groups;
+        $nestedGroups = $this->access->connection->ldapNestedGroups;
+        if (intval($nestedGroups) === 1) {
+            foreach ($groups as $group) {
+                $subGroups = $this->_getGroupDNsFromMemberOf($group, $seen);
+                $allGroups = array_merge($allGroups, $subGroups);
+            }
+        }
+        return $allGroups;
+    }
+
+    /**
+     * translates a gidNumber into an ownCloud internal name
+     * @param string $gid as given by gidNumber on POSIX LDAP
+     * @param string $dn a DN that belongs to the same domain as the group
+     * @return string|bool
+     */
+    public function gidNumber2Name($gid, $dn) {
+        $cacheKey = 'gidNumberToName' . $gid;
+        $groupName = $this->access->connection->getFromCache($cacheKey);
+        if(!is_null($groupName) && isset($groupName)) {
+            return $groupName;
+        }
+
+        //we need to get the DN from LDAP
+        $filter = $this->access->combineFilterWithAnd([
+            $this->access->connection->ldapGroupFilter,
+            'objectClass=posixGroup',
+            $this->access->connection->ldapGidNumber . '=' . $gid
+        ]);
+        $result = $this->access->searchGroups($filter, array('dn'), 1);
+        if(empty($result)) {
+            return false;
+        }
+        $dn = $result[0]['dn'][0];
+
+        //and now the group name
+        //NOTE once we have separate ownCloud group IDs and group names we can
+        //directly read the display name attribute instead of the DN
+        $name = $this->access->dn2groupname($dn);
+
+        $this->access->connection->writeToCache($cacheKey, $name);
+
+        return $name;
+    }
+
+    /**
+     * returns the entry's gidNumber
+     * @param string $dn
+     * @param string $attribute
+     * @return string|bool
+     */
+    private function getEntryGidNumber($dn, $attribute) {
+        $value = $this->access->readAttribute($dn, $attribute);
+        if(is_array($value) && !empty($value)) {
+            return $value[0];
+        }
+        return false;
+    }
+
+    /**
+     * returns the group's primary ID
+     * @param string $dn
+     * @return string|bool
+     */
+    public function getGroupGidNumber($dn) {
+        return $this->getEntryGidNumber($dn, 'gidNumber');
+    }
+
+    /**
+     * returns the user's gidNumber
+     * @param string $dn
+     * @return string|bool
+     */
+    public function getUserGidNumber($dn) {
+        $gidNumber = false;
+        if($this->access->connection->hasGidNumber) {
+            $gidNumber = $this->getEntryGidNumber($dn, $this->access->connection->ldapGidNumber);
+            if($gidNumber === false) {
+                $this->access->connection->hasGidNumber = false;
+            }
+        }
+        return $gidNumber;
+    }
+
+    /**
+     * returns a filter for a "users has specific gid" search or count operation
+     *
+     * @param string $groupDN
+     * @param string $search
+     * @return string
+     * @throws \Exception
+     */
+    private function prepareFilterForUsersHasGidNumber($groupDN, $search = '') {
+        $groupID = $this->getGroupGidNumber($groupDN);
+        if($groupID === false) {
+            throw new \Exception('Not a valid group');
+        }
+
+        $filterParts = [];
+        $filterParts[] = $this->access->getFilterForUserCount();
+        if ($search !== '') {
+            $filterParts[] = $this->access->getFilterPartForUserSearch($search);
+        }
+        $filterParts[] = $this->access->connection->ldapGidNumber .'=' . $groupID;
+
+        $filter = $this->access->combineFilterWithAnd($filterParts);
+
+        return $filter;
+    }
+
+    /**
+     * returns a list of users that have the given group as gid number
+     *
+     * @param string $groupDN
+     * @param string $search
+     * @param int $limit
+     * @param int $offset
+     * @return string[]
+     */
+    public function getUsersInGidNumber($groupDN, $search = '', $limit = -1, $offset = 0) {
+        try {
+            $filter = $this->prepareFilterForUsersHasGidNumber($groupDN, $search);
+            $users = $this->access->fetchListOfUsers(
+                $filter,
+                [$this->access->connection->ldapUserDisplayName, 'dn'],
+                $limit,
+                $offset
+            );
+            return $this->access->nextcloudUserNames($users);
+        } catch (\Exception $e) {
+            return [];
+        }
+    }
+
+    /**
+     * returns the number of users that have the given group as gid number
+     *
+     * @param string $groupDN
+     * @param string $search
+     * @param int $limit
+     * @param int $offset
+     * @return int
+     */
+    public function countUsersInGidNumber($groupDN, $search = '', $limit = -1, $offset = 0) {
+        try {
+            $filter = $this->prepareFilterForUsersHasGidNumber($groupDN, $search);
+            $users = $this->access->countUsers($filter, ['dn'], $limit, $offset);
+            return (int)$users;
+        } catch (\Exception $e) {
+            return 0;
+        }
+    }
+
+    /**
+     * gets the gidNumber of a user
+     * @param string $dn
+     * @return string
+     */
+    public function getUserGroupByGid($dn) {
+        $groupID = $this->getUserGidNumber($dn);
+        if($groupID !== false) {
+            $groupName = $this->gidNumber2Name($groupID, $dn);
+            if($groupName !== false) {
+                return $groupName;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * translates a primary group ID into an Nextcloud internal name
+     * @param string $gid as given by primaryGroupID on AD
+     * @param string $dn a DN that belongs to the same domain as the group
+     * @return string|bool
+     */
+    public function primaryGroupID2Name($gid, $dn) {
+        $cacheKey = 'primaryGroupIDtoName';
+        $groupNames = $this->access->connection->getFromCache($cacheKey);
+        if(!is_null($groupNames) && isset($groupNames[$gid])) {
+            return $groupNames[$gid];
+        }
+
+        $domainObjectSid = $this->access->getSID($dn);
+        if($domainObjectSid === false) {
+            return false;
+        }
+
+        //we need to get the DN from LDAP
+        $filter = $this->access->combineFilterWithAnd(array(
+            $this->access->connection->ldapGroupFilter,
+            'objectsid=' . $domainObjectSid . '-' . $gid
+        ));
+        $result = $this->access->searchGroups($filter, array('dn'), 1);
+        if(empty($result)) {
+            return false;
+        }
+        $dn = $result[0]['dn'][0];
+
+        //and now the group name
+        //NOTE once we have separate Nextcloud group IDs and group names we can
+        //directly read the display name attribute instead of the DN
+        $name = $this->access->dn2groupname($dn);
+
+        $this->access->connection->writeToCache($cacheKey, $name);
+
+        return $name;
+    }
+
+    /**
+     * returns the entry's primary group ID
+     * @param string $dn
+     * @param string $attribute
+     * @return string|bool
+     */
+    private function getEntryGroupID($dn, $attribute) {
+        $value = $this->access->readAttribute($dn, $attribute);
+        if(is_array($value) && !empty($value)) {
+            return $value[0];
+        }
+        return false;
+    }
+
+    /**
+     * returns the group's primary ID
+     * @param string $dn
+     * @return string|bool
+     */
+    public function getGroupPrimaryGroupID($dn) {
+        return $this->getEntryGroupID($dn, 'primaryGroupToken');
+    }
+
+    /**
+     * returns the user's primary group ID
+     * @param string $dn
+     * @return string|bool
+     */
+    public function getUserPrimaryGroupIDs($dn) {
+        $primaryGroupID = false;
+        if($this->access->connection->hasPrimaryGroups) {
+            $primaryGroupID = $this->getEntryGroupID($dn, 'primaryGroupID');
+            if($primaryGroupID === false) {
+                $this->access->connection->hasPrimaryGroups = false;
+            }
+        }
+        return $primaryGroupID;
+    }
+
+    /**
+     * returns a filter for a "users in primary group" search or count operation
+     *
+     * @param string $groupDN
+     * @param string $search
+     * @return string
+     * @throws \Exception
+     */
+    private function prepareFilterForUsersInPrimaryGroup($groupDN, $search = '') {
+        $groupID = $this->getGroupPrimaryGroupID($groupDN);
+        if($groupID === false) {
+            throw new \Exception('Not a valid group');
+        }
+
+        $filterParts = [];
+        $filterParts[] = $this->access->getFilterForUserCount();
+        if ($search !== '') {
+            $filterParts[] = $this->access->getFilterPartForUserSearch($search);
+        }
+        $filterParts[] = 'primaryGroupID=' . $groupID;
+
+        $filter = $this->access->combineFilterWithAnd($filterParts);
+
+        return $filter;
+    }
+
+    /**
+     * returns a list of users that have the given group as primary group
+     *
+     * @param string $groupDN
+     * @param string $search
+     * @param int $limit
+     * @param int $offset
+     * @return string[]
+     */
+    public function getUsersInPrimaryGroup($groupDN, $search = '', $limit = -1, $offset = 0) {
+        try {
+            $filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
+            $users = $this->access->fetchListOfUsers(
+                $filter,
+                array($this->access->connection->ldapUserDisplayName, 'dn'),
+                $limit,
+                $offset
+            );
+            return $this->access->nextcloudUserNames($users);
+        } catch (\Exception $e) {
+            return array();
+        }
+    }
+
+    /**
+     * returns the number of users that have the given group as primary group
+     *
+     * @param string $groupDN
+     * @param string $search
+     * @param int $limit
+     * @param int $offset
+     * @return int
+     */
+    public function countUsersInPrimaryGroup($groupDN, $search = '', $limit = -1, $offset = 0) {
+        try {
+            $filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
+            $users = $this->access->countUsers($filter, array('dn'), $limit, $offset);
+            return (int)$users;
+        } catch (\Exception $e) {
+            return 0;
+        }
+    }
+
+    /**
+     * gets the primary group of a user
+     * @param string $dn
+     * @return string
+     */
+    public function getUserPrimaryGroup($dn) {
+        $groupID = $this->getUserPrimaryGroupIDs($dn);
+        if($groupID !== false) {
+            $groupName = $this->primaryGroupID2Name($groupID, $dn);
+            if($groupName !== false) {
+                return $groupName;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Get all groups a user belongs to
+     * @param string $uid Name of the user
+     * @return array with group names
+     *
+     * This function fetches all groups a user belongs to. It does not check
+     * if the user exists at all.
+     *
+     * This function includes groups based on dynamic group membership.
+     */
+    public function getUserGroups($uid) {
+        if(!$this->enabled) {
+            return array();
+        }
+        $cacheKey = 'getUserGroups'.$uid;
+        $userGroups = $this->access->connection->getFromCache($cacheKey);
+        if(!is_null($userGroups)) {
+            return $userGroups;
+        }
+        $userDN = $this->access->username2dn($uid);
+        if(!$userDN) {
+            $this->access->connection->writeToCache($cacheKey, array());
+            return array();
+        }
+
+        $groups = [];
+        $primaryGroup = $this->getUserPrimaryGroup($userDN);
+        $gidGroupName = $this->getUserGroupByGid($userDN);
+
+        $dynamicGroupMemberURL = strtolower($this->access->connection->ldapDynamicGroupMemberURL);
+
+        if (!empty($dynamicGroupMemberURL)) {
+            // look through dynamic groups to add them to the result array if needed
+            $groupsToMatch = $this->access->fetchListOfGroups(
+                $this->access->connection->ldapGroupFilter,array('dn',$dynamicGroupMemberURL));
+            foreach($groupsToMatch as $dynamicGroup) {
+                if (!array_key_exists($dynamicGroupMemberURL, $dynamicGroup)) {
+                    continue;
+                }
+                $pos = strpos($dynamicGroup[$dynamicGroupMemberURL][0], '(');
+                if ($pos !== false) {
+                    $memberUrlFilter = substr($dynamicGroup[$dynamicGroupMemberURL][0],$pos);
+                    // apply filter via ldap search to see if this user is in this
+                    // dynamic group
+                    $userMatch = $this->access->readAttribute(
+                        $userDN,
+                        $this->access->connection->ldapUserDisplayName,
+                        $memberUrlFilter
+                    );
+                    if ($userMatch !== false) {
+                        // match found so this user is in this group
+                        $groupName = $this->access->dn2groupname($dynamicGroup['dn'][0]);
+                        if(is_string($groupName)) {
+                            // be sure to never return false if the dn could not be
+                            // resolved to a name, for whatever reason.
+                            $groups[] = $groupName;
+                        }
+                    }
+                } else {
+                    \OCP\Util::writeLog('user_ldap', 'No search filter found on member url '.
+                        'of group ' . print_r($dynamicGroup, true), \OCP\Util::DEBUG);
+                }
+            }
+        }
+
+        // if possible, read out membership via memberOf. It's far faster than
+        // performing a search, which still is a fallback later.
+        // memberof doesn't support memberuid, so skip it here.
+        if(intval($this->access->connection->hasMemberOfFilterSupport) === 1
+            && intval($this->access->connection->useMemberOfToDetectMembership) === 1
+            && strtolower($this->access->connection->ldapGroupMemberAssocAttr) !== 'memberuid'
+            ) {
+            $groupDNs = $this->_getGroupDNsFromMemberOf($userDN);
+            if (is_array($groupDNs)) {
+                foreach ($groupDNs as $dn) {
+                    $groupName = $this->access->dn2groupname($dn);
+                    if(is_string($groupName)) {
+                        // be sure to never return false if the dn could not be
+                        // resolved to a name, for whatever reason.
+                        $groups[] = $groupName;
+                    }
+                }
+            }
+
+            if($primaryGroup !== false) {
+                $groups[] = $primaryGroup;
+            }
+            if($gidGroupName !== false) {
+                $groups[] = $gidGroupName;
+            }
+            $this->access->connection->writeToCache($cacheKey, $groups);
+            return $groups;
+        }
+
+        //uniqueMember takes DN, memberuid the uid, so we need to distinguish
+        if((strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'uniquemember')
+            || (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'member')
+        ) {
+            $uid = $userDN;
+        } else if(strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {
+            $result = $this->access->readAttribute($userDN, 'uid');
+            if ($result === false) {
+                \OCP\Util::writeLog('user_ldap', 'No uid attribute found for DN ' . $userDN . ' on '.
+                    $this->access->connection->ldapHost, \OCP\Util::DEBUG);
+            }
+            $uid = $result[0];
+        } else {
+            // just in case
+            $uid = $userDN;
+        }
+
+        if(isset($this->cachedGroupsByMember[$uid])) {
+            $groups = array_merge($groups, $this->cachedGroupsByMember[$uid]);
+        } else {
+            $groupsByMember = array_values($this->getGroupsByMember($uid));
+            $groupsByMember = $this->access->nextcloudGroupNames($groupsByMember);
+            $this->cachedGroupsByMember[$uid] = $groupsByMember;
+            $groups = array_merge($groups, $groupsByMember);
+        }
+
+        if($primaryGroup !== false) {
+            $groups[] = $primaryGroup;
+        }
+        if($gidGroupName !== false) {
+            $groups[] = $gidGroupName;
+        }
+
+        $groups = array_unique($groups, SORT_LOCALE_STRING);
+        $this->access->connection->writeToCache($cacheKey, $groups);
+
+        return $groups;
+    }
+
+    /**
+     * @param string $dn
+     * @param array|null &$seen
+     * @return array
+     */
+    private function getGroupsByMember($dn, &$seen = null) {
+        if ($seen === null) {
+            $seen = array();
+        }
+        $allGroups = array();
+        if (array_key_exists($dn, $seen)) {
+            // avoid loops
+            return array();
+        }
+        $seen[$dn] = true;
+        $filter = $this->access->combineFilterWithAnd(array(
+            $this->access->connection->ldapGroupFilter,
+            $this->access->connection->ldapGroupMemberAssocAttr.'='.$dn
+        ));
+        $groups = $this->access->fetchListOfGroups($filter,
+            array($this->access->connection->ldapGroupDisplayName, 'dn'));
+        if (is_array($groups)) {
+            foreach ($groups as $groupobj) {
+                $groupDN = $groupobj['dn'][0];
+                $allGroups[$groupDN] = $groupobj;
+                $nestedGroups = $this->access->connection->ldapNestedGroups;
+                if (!empty($nestedGroups)) {
+                    $supergroups = $this->getGroupsByMember($groupDN, $seen);
+                    if (is_array($supergroups) && (count($supergroups)>0)) {
+                        $allGroups = array_merge($allGroups, $supergroups);
+                    }
+                }
+            }
+        }
+        return $allGroups;
+    }
+
+    /**
+     * get a list of all users in a group
+     *
+     * @param string $gid
+     * @param string $search
+     * @param int $limit
+     * @param int $offset
+     * @return array with user ids
+     */
+    public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
+        if(!$this->enabled) {
+            return array();
+        }
+        if(!$this->groupExists($gid)) {
+            return array();
+        }
+        $search = $this->access->escapeFilterPart($search, true);
+        $cacheKey = 'usersInGroup-'.$gid.'-'.$search.'-'.$limit.'-'.$offset;
+        // check for cache of the exact query
+        $groupUsers = $this->access->connection->getFromCache($cacheKey);
+        if(!is_null($groupUsers)) {
+            return $groupUsers;
+        }
+
+        // check for cache of the query without limit and offset
+        $groupUsers = $this->access->connection->getFromCache('usersInGroup-'.$gid.'-'.$search);
+        if(!is_null($groupUsers)) {
+            $groupUsers = array_slice($groupUsers, $offset, $limit);
+            $this->access->connection->writeToCache($cacheKey, $groupUsers);
+            return $groupUsers;
+        }
+
+        if($limit === -1) {
+            $limit = null;
+        }
+        $groupDN = $this->access->groupname2dn($gid);
+        if(!$groupDN) {
+            // group couldn't be found, return empty resultset
+            $this->access->connection->writeToCache($cacheKey, array());
+            return array();
+        }
+
+        $primaryUsers = $this->getUsersInPrimaryGroup($groupDN, $search, $limit, $offset);
+        $posixGroupUsers = $this->getUsersInGidNumber($groupDN, $search, $limit, $offset);
+        $members = array_keys($this->_groupMembers($groupDN));
+        if(!$members && empty($posixGroupUsers) && empty($primaryUsers)) {
+            //in case users could not be retrieved, return empty result set
+            $this->access->connection->writeToCache($cacheKey, []);
+            return [];
+        }
+
+        $groupUsers = array();
+        $isMemberUid = (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid');
+        $attrs = $this->access->userManager->getAttributes(true);
+        foreach($members as $member) {
+            if($isMemberUid) {
+                //we got uids, need to get their DNs to 'translate' them to user names
+                $filter = $this->access->combineFilterWithAnd(array(
+                    str_replace('%uid', $member, $this->access->connection->ldapLoginFilter),
+                    $this->access->getFilterPartForUserSearch($search)
+                ));
+                $ldap_users = $this->access->fetchListOfUsers($filter, $attrs, 1);
+                if(count($ldap_users) < 1) {
+                    continue;
+                }
+                $groupUsers[] = $this->access->dn2username($ldap_users[0]['dn'][0]);
+            } else {
+                //we got DNs, check if we need to filter by search or we can give back all of them
+                if ($search !== '') {
+                    if(!$this->access->readAttribute($member,
+                        $this->access->connection->ldapUserDisplayName,
+                        $this->access->getFilterPartForUserSearch($search))) {
+                        continue;
+                    }
+                }
+                // dn2username will also check if the users belong to the allowed base
+                if($ocname = $this->access->dn2username($member)) {
+                    $groupUsers[] = $ocname;
+                }
+            }
+        }
+
+        $groupUsers = array_unique(array_merge($groupUsers, $primaryUsers, $posixGroupUsers));
+        natsort($groupUsers);
+        $this->access->connection->writeToCache('usersInGroup-'.$gid.'-'.$search, $groupUsers);
+        $groupUsers = array_slice($groupUsers, $offset, $limit);
+
+        $this->access->connection->writeToCache($cacheKey, $groupUsers);
+
+        return $groupUsers;
+    }
+
+    /**
+     * returns the number of users in a group, who match the search term
+     * @param string $gid the internal group name
+     * @param string $search optional, a search string
+     * @return int|bool
+     */
+    public function countUsersInGroup($gid, $search = '') {
+        $cacheKey = 'countUsersInGroup-'.$gid.'-'.$search;
+        if(!$this->enabled || !$this->groupExists($gid)) {
+            return false;
+        }
+        $groupUsers = $this->access->connection->getFromCache($cacheKey);
+        if(!is_null($groupUsers)) {
+            return $groupUsers;
+        }
+
+        $groupDN = $this->access->groupname2dn($gid);
+        if(!$groupDN) {
+            // group couldn't be found, return empty result set
+            $this->access->connection->writeToCache($cacheKey, false);
+            return false;
+        }
+
+        $members = array_keys($this->_groupMembers($groupDN));
+        $primaryUserCount = $this->countUsersInPrimaryGroup($groupDN, '');
+        if(!$members && $primaryUserCount === 0) {
+            //in case users could not be retrieved, return empty result set
+            $this->access->connection->writeToCache($cacheKey, false);
+            return false;
+        }
+
+        if ($search === '') {
+            $groupUsers = count($members) + $primaryUserCount;
+            $this->access->connection->writeToCache($cacheKey, $groupUsers);
+            return $groupUsers;
+        }
+        $search = $this->access->escapeFilterPart($search, true);
+        $isMemberUid =
+            (strtolower($this->access->connection->ldapGroupMemberAssocAttr)
+            === 'memberuid');
+
+        //we need to apply the search filter
+        //alternatives that need to be checked:
+        //a) get all users by search filter and array_intersect them
+        //b) a, but only when less than 1k 10k ?k users like it is
+        //c) put all DNs|uids in a LDAP filter, combine with the search string
+        //   and let it count.
+        //For now this is not important, because the only use of this method
+        //does not supply a search string
+        $groupUsers = array();
+        foreach($members as $member) {
+            if($isMemberUid) {
+                //we got uids, need to get their DNs to 'translate' them to user names
+                $filter = $this->access->combineFilterWithAnd(array(
+                    str_replace('%uid', $member, $this->access->connection->ldapLoginFilter),
+                    $this->access->getFilterPartForUserSearch($search)
+                ));
+                $ldap_users = $this->access->fetchListOfUsers($filter, 'dn', 1);
+                if(count($ldap_users) < 1) {
+                    continue;
+                }
+                $groupUsers[] = $this->access->dn2username($ldap_users[0]);
+            } else {
+                //we need to apply the search filter now
+                if(!$this->access->readAttribute($member,
+                    $this->access->connection->ldapUserDisplayName,
+                    $this->access->getFilterPartForUserSearch($search))) {
+                    continue;
+                }
+                // dn2username will also check if the users belong to the allowed base
+                if($ocname = $this->access->dn2username($member)) {
+                    $groupUsers[] = $ocname;
+                }
+            }
+        }
+
+        //and get users that have the group as primary
+        $primaryUsers = $this->countUsersInPrimaryGroup($groupDN, $search);
+
+        return count($groupUsers) + $primaryUsers;
+    }
+
+    /**
+     * get a list of all groups
+     *
+     * @param string $search
+     * @param $limit
+     * @param int $offset
+     * @return array with group names
+     *
+     * Returns a list with all groups (used by getGroups)
+     */
+    protected function getGroupsChunk($search = '', $limit = -1, $offset = 0) {
+        if(!$this->enabled) {
+            return array();
+        }
+        $cacheKey = 'getGroups-'.$search.'-'.$limit.'-'.$offset;
+
+        //Check cache before driving unnecessary searches
+        \OCP\Util::writeLog('user_ldap', 'getGroups '.$cacheKey, \OCP\Util::DEBUG);
+        $ldap_groups = $this->access->connection->getFromCache($cacheKey);
+        if(!is_null($ldap_groups)) {
+            return $ldap_groups;
+        }
+
+        // if we'd pass -1 to LDAP search, we'd end up in a Protocol
+        // error. With a limit of 0, we get 0 results. So we pass null.
+        if($limit <= 0) {
+            $limit = null;
+        }
+        $filter = $this->access->combineFilterWithAnd(array(
+            $this->access->connection->ldapGroupFilter,
+            $this->access->getFilterPartForGroupSearch($search)
+        ));
+        \OCP\Util::writeLog('user_ldap', 'getGroups Filter '.$filter, \OCP\Util::DEBUG);
+        $ldap_groups = $this->access->fetchListOfGroups($filter,
+                array($this->access->connection->ldapGroupDisplayName, 'dn'),
+                $limit,
+                $offset);
+        $ldap_groups = $this->access->nextcloudGroupNames($ldap_groups);
+
+        $this->access->connection->writeToCache($cacheKey, $ldap_groups);
+        return $ldap_groups;
+    }
+
+    /**
+     * get a list of all groups using a paged search
+     *
+     * @param string $search
+     * @param int $limit
+     * @param int $offset
+     * @return array with group names
+     *
+     * Returns a list with all groups
+     * Uses a paged search if available to override a
+     * server side search limit.
+     * (active directory has a limit of 1000 by default)
+     */
+    public function getGroups($search = '', $limit = -1, $offset = 0) {
+        if(!$this->enabled) {
+            return array();
+        }
+        $search = $this->access->escapeFilterPart($search, true);
+        $pagingSize = intval($this->access->connection->ldapPagingSize);
+        if (!$this->access->connection->hasPagedResultSupport || $pagingSize <= 0) {
+            return $this->getGroupsChunk($search, $limit, $offset);
+        }
+        $maxGroups = 100000; // limit max results (just for safety reasons)
+        if ($limit > -1) {
+            $overallLimit = min($limit + $offset, $maxGroups);
+        } else {
+            $overallLimit = $maxGroups;
+        }
+        $chunkOffset = $offset;
+        $allGroups = array();
+        while ($chunkOffset < $overallLimit) {
+            $chunkLimit = min($pagingSize, $overallLimit - $chunkOffset);
+            $ldapGroups = $this->getGroupsChunk($search, $chunkLimit, $chunkOffset);
+            $nread = count($ldapGroups);
+            \OCP\Util::writeLog('user_ldap', 'getGroups('.$search.'): read '.$nread.' at offset '.$chunkOffset.' (limit: '.$chunkLimit.')', \OCP\Util::DEBUG);
+            if ($nread) {
+                $allGroups = array_merge($allGroups, $ldapGroups);
+                $chunkOffset += $nread;
+            }
+            if ($nread < $chunkLimit) {
+                break;
+            }
+        }
+        return $allGroups;
+    }
+
+    /**
+     * @param string $group
+     * @return bool
+     */
+    public function groupMatchesFilter($group) {
+        return (strripos($group, $this->groupSearch) !== false);
+    }
+
+    /**
+     * check if a group exists
+     * @param string $gid
+     * @return bool
+     */
+    public function groupExists($gid) {
+        $groupExists = $this->access->connection->getFromCache('groupExists'.$gid);
+        if(!is_null($groupExists)) {
+            return (bool)$groupExists;
+        }
+
+        //getting dn, if false the group does not exist. If dn, it may be mapped
+        //only, requires more checking.
+        $dn = $this->access->groupname2dn($gid);
+        if(!$dn) {
+            $this->access->connection->writeToCache('groupExists'.$gid, false);
+            return false;
+        }
+
+        //if group really still exists, we will be able to read its objectclass
+        if(!is_array($this->access->readAttribute($dn, ''))) {
+            $this->access->connection->writeToCache('groupExists'.$gid, false);
+            return false;
+        }
+
+        $this->access->connection->writeToCache('groupExists'.$gid, true);
+        return true;
+    }
+
+    /**
+     * Check if backend implements actions
+     * @param int $actions bitwise-or'ed actions
+     * @return boolean
+     *
+     * Returns the supported actions as int to be
+     * compared with \OC\User\Backend::CREATE_USER etc.
+     */
+    public function implementsActions($actions) {
+        return (bool)(\OC\Group\Backend::COUNT_USERS & $actions);
+    }
+
+    /**
+     * Return access for LDAP interaction.
+     * @return Access instance of Access for LDAP interaction
+     */
+    public function getLDAPAccess() {
+        return $this->access;
+    }
 }

Spacing +91 added lines, -91 removed lines

@@ -57,7 +57,7 @@ 
 		parent::__construct($access);
 		$filter = $this->access->connection->ldapGroupFilter;
 		$gassoc = $this->access->connection->ldapGroupMemberAssocAttr;
-		if(!empty($filter) && !empty($gassoc)) {
+		if (!empty($filter) && !empty($gassoc)) {
 			$this->enabled = true;
 		}
 
@@ -74,25 +74,25 @@ 
 	 * Checks whether the user is member of a group or not.
 	 */
 	public function inGroup($uid, $gid) {
-		if(!$this->enabled) {
+		if (!$this->enabled) {
 			return false;
 		}
 		$cacheKey = 'inGroup'.$uid.':'.$gid;
 		$inGroup = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($inGroup)) {
-			return (bool)$inGroup;
+		if (!is_null($inGroup)) {
+			return (bool) $inGroup;
 		}
 
 		$userDN = $this->access->username2dn($uid);
 
-		if(isset($this->cachedGroupMembers[$gid])) {
+		if (isset($this->cachedGroupMembers[$gid])) {
 			$isInGroup = in_array($userDN, $this->cachedGroupMembers[$gid]);
 			return $isInGroup;
 		}
 
 		$cacheKeyMembers = 'inGroup-members:'.$gid;
 		$members = $this->access->connection->getFromCache($cacheKeyMembers);
-		if(!is_null($members)) {
+		if (!is_null($members)) {
 			$this->cachedGroupMembers[$gid] = $members;
 			$isInGroup = in_array($userDN, $members);
 			$this->access->connection->writeToCache($cacheKey, $isInGroup);
@@ -101,13 +101,13 @@ 
 
 		$groupDN = $this->access->groupname2dn($gid);
 		// just in case
-		if(!$groupDN || !$userDN) {
+		if (!$groupDN || !$userDN) {
 			$this->access->connection->writeToCache($cacheKey, false);
 			return false;
 		}
 
 		//check primary group first
-		if($gid === $this->getUserPrimaryGroup($userDN)) {
+		if ($gid === $this->getUserPrimaryGroup($userDN)) {
 			$this->access->connection->writeToCache($cacheKey, true);
 			return true;
 		}
@@ -115,21 +115,21 @@ 
 		//usually, LDAP attributes are said to be case insensitive. But there are exceptions of course.
 		$members = $this->_groupMembers($groupDN);
 		$members = array_keys($members); // uids are returned as keys
-		if(!is_array($members) || count($members) === 0) {
+		if (!is_array($members) || count($members) === 0) {
 			$this->access->connection->writeToCache($cacheKey, false);
 			return false;
 		}
 
 		//extra work if we don't get back user DNs
-		if(strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {
+		if (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {
 			$dns = array();
 			$filterParts = array();
 			$bytes = 0;
-			foreach($members as $mid) {
+			foreach ($members as $mid) {
 				$filter = str_replace('%uid', $mid, $this->access->connection->ldapLoginFilter);
 				$filterParts[] = $filter;
 				$bytes += strlen($filter);
-				if($bytes >= 9000000) {
+				if ($bytes >= 9000000) {
 					// AD has a default input buffer of 10 MB, we do not want
 					// to take even the chance to exceed it
 					$filter = $this->access->combineFilterWithOr($filterParts);
@@ -139,7 +139,7 @@ 
 					$dns = array_merge($dns, $users);
 				}
 			}
-			if(count($filterParts) > 0) {
+			if (count($filterParts) > 0) {
 				$filter = $this->access->combineFilterWithOr($filterParts);
 				$users = $this->access->fetchListOfUsers($filter, 'dn', count($filterParts));
 				$dns = array_merge($dns, $users);
@@ -182,14 +182,14 @@ 
 			$pos = strpos($memberURLs[0], '(');
 			if ($pos !== false) {
 				$memberUrlFilter = substr($memberURLs[0], $pos);
-				$foundMembers = $this->access->searchUsers($memberUrlFilter,'dn');
+				$foundMembers = $this->access->searchUsers($memberUrlFilter, 'dn');
 				$dynamicMembers = array();
-				foreach($foundMembers as $value) {
+				foreach ($foundMembers as $value) {
 					$dynamicMembers[$value['dn'][0]] = 1;
 				}
 			} else {
 				\OCP\Util::writeLog('user_ldap', 'No search filter found on member url '.
-					'of group ' . $dnGroup, \OCP\Util::DEBUG);
+					'of group '.$dnGroup, \OCP\Util::DEBUG);
 			}
 		}
 		return $dynamicMembers;
@@ -212,7 +212,7 @@ 
 		// used extensively in cron job, caching makes sense for nested groups
 		$cacheKey = '_groupMembers'.$dnGroup;
 		$groupMembers = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupMembers)) {
+		if (!is_null($groupMembers)) {
 			return $groupMembers;
 		}
 		$seen[$dnGroup] = 1;
@@ -256,7 +256,7 @@ 
 			return array();
 		}
 		$groups = $this->access->groupsMatchFilter($groups);
-		$allGroups =  $groups;
+		$allGroups = $groups;
 		$nestedGroups = $this->access->connection->ldapNestedGroups;
 		if (intval($nestedGroups) === 1) {
 			foreach ($groups as $group) {
@@ -274,9 +274,9 @@ 
 	 * @return string|bool
 	 */
 	public function gidNumber2Name($gid, $dn) {
-		$cacheKey = 'gidNumberToName' . $gid;
+		$cacheKey = 'gidNumberToName'.$gid;
 		$groupName = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupName) && isset($groupName)) {
+		if (!is_null($groupName) && isset($groupName)) {
 			return $groupName;
 		}
 
@@ -284,10 +284,10 @@ 
 		$filter = $this->access->combineFilterWithAnd([
 			$this->access->connection->ldapGroupFilter,
 			'objectClass=posixGroup',
-			$this->access->connection->ldapGidNumber . '=' . $gid
+			$this->access->connection->ldapGidNumber.'='.$gid
 		]);
 		$result = $this->access->searchGroups($filter, array('dn'), 1);
-		if(empty($result)) {
+		if (empty($result)) {
 			return false;
 		}
 		$dn = $result[0]['dn'][0];
@@ -310,7 +310,7 @@ 
 	 */
 	private function getEntryGidNumber($dn, $attribute) {
 		$value = $this->access->readAttribute($dn, $attribute);
-		if(is_array($value) && !empty($value)) {
+		if (is_array($value) && !empty($value)) {
 			return $value[0];
 		}
 		return false;
@@ -332,9 +332,9 @@ 
 	 */
 	public function getUserGidNumber($dn) {
 		$gidNumber = false;
-		if($this->access->connection->hasGidNumber) {
+		if ($this->access->connection->hasGidNumber) {
 			$gidNumber = $this->getEntryGidNumber($dn, $this->access->connection->ldapGidNumber);
-			if($gidNumber === false) {
+			if ($gidNumber === false) {
 				$this->access->connection->hasGidNumber = false;
 			}
 		}
@@ -351,7 +351,7 @@ 
 	 */
 	private function prepareFilterForUsersHasGidNumber($groupDN, $search = '') {
 		$groupID = $this->getGroupGidNumber($groupDN);
-		if($groupID === false) {
+		if ($groupID === false) {
 			throw new \Exception('Not a valid group');
 		}
 
@@ -360,7 +360,7 @@ 
 		if ($search !== '') {
 			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
 		}
-		$filterParts[] = $this->access->connection->ldapGidNumber .'=' . $groupID;
+		$filterParts[] = $this->access->connection->ldapGidNumber.'='.$groupID;
 
 		$filter = $this->access->combineFilterWithAnd($filterParts);
 
@@ -404,7 +404,7 @@ 
 		try {
 			$filter = $this->prepareFilterForUsersHasGidNumber($groupDN, $search);
 			$users = $this->access->countUsers($filter, ['dn'], $limit, $offset);
-			return (int)$users;
+			return (int) $users;
 		} catch (\Exception $e) {
 			return 0;
 		}
@@ -417,9 +417,9 @@ 
 	 */
 	public function getUserGroupByGid($dn) {
 		$groupID = $this->getUserGidNumber($dn);
-		if($groupID !== false) {
+		if ($groupID !== false) {
 			$groupName = $this->gidNumber2Name($groupID, $dn);
-			if($groupName !== false) {
+			if ($groupName !== false) {
 				return $groupName;
 			}
 		}
@@ -436,22 +436,22 @@ 
 	public function primaryGroupID2Name($gid, $dn) {
 		$cacheKey = 'primaryGroupIDtoName';
 		$groupNames = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupNames) && isset($groupNames[$gid])) {
+		if (!is_null($groupNames) && isset($groupNames[$gid])) {
 			return $groupNames[$gid];
 		}
 
 		$domainObjectSid = $this->access->getSID($dn);
-		if($domainObjectSid === false) {
+		if ($domainObjectSid === false) {
 			return false;
 		}
 
 		//we need to get the DN from LDAP
 		$filter = $this->access->combineFilterWithAnd(array(
 			$this->access->connection->ldapGroupFilter,
-			'objectsid=' . $domainObjectSid . '-' . $gid
+			'objectsid='.$domainObjectSid.'-'.$gid
 		));
 		$result = $this->access->searchGroups($filter, array('dn'), 1);
-		if(empty($result)) {
+		if (empty($result)) {
 			return false;
 		}
 		$dn = $result[0]['dn'][0];
@@ -474,7 +474,7 @@ 
 	 */
 	private function getEntryGroupID($dn, $attribute) {
 		$value = $this->access->readAttribute($dn, $attribute);
-		if(is_array($value) && !empty($value)) {
+		if (is_array($value) && !empty($value)) {
 			return $value[0];
 		}
 		return false;
@@ -496,9 +496,9 @@ 
 	 */
 	public function getUserPrimaryGroupIDs($dn) {
 		$primaryGroupID = false;
-		if($this->access->connection->hasPrimaryGroups) {
+		if ($this->access->connection->hasPrimaryGroups) {
 			$primaryGroupID = $this->getEntryGroupID($dn, 'primaryGroupID');
-			if($primaryGroupID === false) {
+			if ($primaryGroupID === false) {
 				$this->access->connection->hasPrimaryGroups = false;
 			}
 		}
@@ -515,7 +515,7 @@ 
 	 */
 	private function prepareFilterForUsersInPrimaryGroup($groupDN, $search = '') {
 		$groupID = $this->getGroupPrimaryGroupID($groupDN);
-		if($groupID === false) {
+		if ($groupID === false) {
 			throw new \Exception('Not a valid group');
 		}
 
@@ -524,7 +524,7 @@ 
 		if ($search !== '') {
 			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
 		}
-		$filterParts[] = 'primaryGroupID=' . $groupID;
+		$filterParts[] = 'primaryGroupID='.$groupID;
 
 		$filter = $this->access->combineFilterWithAnd($filterParts);
 
@@ -568,7 +568,7 @@ 
 		try {
 			$filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
 			$users = $this->access->countUsers($filter, array('dn'), $limit, $offset);
-			return (int)$users;
+			return (int) $users;
 		} catch (\Exception $e) {
 			return 0;
 		}
@@ -581,9 +581,9 @@ 
 	 */
 	public function getUserPrimaryGroup($dn) {
 		$groupID = $this->getUserPrimaryGroupIDs($dn);
-		if($groupID !== false) {
+		if ($groupID !== false) {
 			$groupName = $this->primaryGroupID2Name($groupID, $dn);
-			if($groupName !== false) {
+			if ($groupName !== false) {
 				return $groupName;
 			}
 		}
@@ -602,16 +602,16 @@ 
 	 * This function includes groups based on dynamic group membership.
 	 */
 	public function getUserGroups($uid) {
-		if(!$this->enabled) {
+		if (!$this->enabled) {
 			return array();
 		}
 		$cacheKey = 'getUserGroups'.$uid;
 		$userGroups = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($userGroups)) {
+		if (!is_null($userGroups)) {
 			return $userGroups;
 		}
 		$userDN = $this->access->username2dn($uid);
-		if(!$userDN) {
+		if (!$userDN) {
 			$this->access->connection->writeToCache($cacheKey, array());
 			return array();
 		}
@@ -625,14 +625,14 @@ 
 		if (!empty($dynamicGroupMemberURL)) {
 			// look through dynamic groups to add them to the result array if needed
 			$groupsToMatch = $this->access->fetchListOfGroups(
-				$this->access->connection->ldapGroupFilter,array('dn',$dynamicGroupMemberURL));
-			foreach($groupsToMatch as $dynamicGroup) {
+				$this->access->connection->ldapGroupFilter, array('dn', $dynamicGroupMemberURL));
+			foreach ($groupsToMatch as $dynamicGroup) {
 				if (!array_key_exists($dynamicGroupMemberURL, $dynamicGroup)) {
 					continue;
 				}
 				$pos = strpos($dynamicGroup[$dynamicGroupMemberURL][0], '(');
 				if ($pos !== false) {
-					$memberUrlFilter = substr($dynamicGroup[$dynamicGroupMemberURL][0],$pos);
+					$memberUrlFilter = substr($dynamicGroup[$dynamicGroupMemberURL][0], $pos);
 					// apply filter via ldap search to see if this user is in this
 					// dynamic group
 					$userMatch = $this->access->readAttribute(
@@ -643,7 +643,7 @@ 
 					if ($userMatch !== false) {
 						// match found so this user is in this group
 						$groupName = $this->access->dn2groupname($dynamicGroup['dn'][0]);
-						if(is_string($groupName)) {
+						if (is_string($groupName)) {
 							// be sure to never return false if the dn could not be
 							// resolved to a name, for whatever reason.
 							$groups[] = $groupName;
@@ -651,7 +651,7 @@ 
 					}
 				} else {
 					\OCP\Util::writeLog('user_ldap', 'No search filter found on member url '.
-						'of group ' . print_r($dynamicGroup, true), \OCP\Util::DEBUG);
+						'of group '.print_r($dynamicGroup, true), \OCP\Util::DEBUG);
 				}
 			}
 		}
@@ -659,7 +659,7 @@ 
 		// if possible, read out membership via memberOf. It's far faster than
 		// performing a search, which still is a fallback later.
 		// memberof doesn't support memberuid, so skip it here.
-		if(intval($this->access->connection->hasMemberOfFilterSupport) === 1
+		if (intval($this->access->connection->hasMemberOfFilterSupport) === 1
 			&& intval($this->access->connection->useMemberOfToDetectMembership) === 1
 		    && strtolower($this->access->connection->ldapGroupMemberAssocAttr) !== 'memberuid'
 		    ) {
@@ -667,7 +667,7 @@ 
 			if (is_array($groupDNs)) {
 				foreach ($groupDNs as $dn) {
 					$groupName = $this->access->dn2groupname($dn);
-					if(is_string($groupName)) {
+					if (is_string($groupName)) {
 						// be sure to never return false if the dn could not be
 						// resolved to a name, for whatever reason.
 						$groups[] = $groupName;
@@ -675,10 +675,10 @@ 
 				}
 			}
 
-			if($primaryGroup !== false) {
+			if ($primaryGroup !== false) {
 				$groups[] = $primaryGroup;
 			}
-			if($gidGroupName !== false) {
+			if ($gidGroupName !== false) {
 				$groups[] = $gidGroupName;
 			}
 			$this->access->connection->writeToCache($cacheKey, $groups);
@@ -686,14 +686,14 @@ 
 		}
 
 		//uniqueMember takes DN, memberuid the uid, so we need to distinguish
-		if((strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'uniquemember')
+		if ((strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'uniquemember')
 			|| (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'member')
 		) {
 			$uid = $userDN;
-		} else if(strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {
+		} else if (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid') {
 			$result = $this->access->readAttribute($userDN, 'uid');
 			if ($result === false) {
-				\OCP\Util::writeLog('user_ldap', 'No uid attribute found for DN ' . $userDN . ' on '.
+				\OCP\Util::writeLog('user_ldap', 'No uid attribute found for DN '.$userDN.' on '.
 					$this->access->connection->ldapHost, \OCP\Util::DEBUG);
 			}
 			$uid = $result[0];
@@ -702,7 +702,7 @@ 
 			$uid = $userDN;
 		}
 
-		if(isset($this->cachedGroupsByMember[$uid])) {
+		if (isset($this->cachedGroupsByMember[$uid])) {
 			$groups = array_merge($groups, $this->cachedGroupsByMember[$uid]);
 		} else {
 			$groupsByMember = array_values($this->getGroupsByMember($uid));
@@ -711,10 +711,10 @@ 
 			$groups = array_merge($groups, $groupsByMember);
 		}
 
-		if($primaryGroup !== false) {
+		if ($primaryGroup !== false) {
 			$groups[] = $primaryGroup;
 		}
-		if($gidGroupName !== false) {
+		if ($gidGroupName !== false) {
 			$groups[] = $gidGroupName;
 		}
 
@@ -752,7 +752,7 @@ 
 				$nestedGroups = $this->access->connection->ldapNestedGroups;
 				if (!empty($nestedGroups)) {
 					$supergroups = $this->getGroupsByMember($groupDN, $seen);
-					if (is_array($supergroups) && (count($supergroups)>0)) {
+					if (is_array($supergroups) && (count($supergroups) > 0)) {
 						$allGroups = array_merge($allGroups, $supergroups);
 					}
 				}
@@ -771,33 +771,33 @@ 
 	 * @return array with user ids
 	 */
 	public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
-		if(!$this->enabled) {
+		if (!$this->enabled) {
 			return array();
 		}
-		if(!$this->groupExists($gid)) {
+		if (!$this->groupExists($gid)) {
 			return array();
 		}
 		$search = $this->access->escapeFilterPart($search, true);
 		$cacheKey = 'usersInGroup-'.$gid.'-'.$search.'-'.$limit.'-'.$offset;
 		// check for cache of the exact query
 		$groupUsers = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupUsers)) {
+		if (!is_null($groupUsers)) {
 			return $groupUsers;
 		}
 
 		// check for cache of the query without limit and offset
 		$groupUsers = $this->access->connection->getFromCache('usersInGroup-'.$gid.'-'.$search);
-		if(!is_null($groupUsers)) {
+		if (!is_null($groupUsers)) {
 			$groupUsers = array_slice($groupUsers, $offset, $limit);
 			$this->access->connection->writeToCache($cacheKey, $groupUsers);
 			return $groupUsers;
 		}
 
-		if($limit === -1) {
+		if ($limit === -1) {
 			$limit = null;
 		}
 		$groupDN = $this->access->groupname2dn($gid);
-		if(!$groupDN) {
+		if (!$groupDN) {
 			// group couldn't be found, return empty resultset
 			$this->access->connection->writeToCache($cacheKey, array());
 			return array();
@@ -806,7 +806,7 @@ 
 		$primaryUsers = $this->getUsersInPrimaryGroup($groupDN, $search, $limit, $offset);
 		$posixGroupUsers = $this->getUsersInGidNumber($groupDN, $search, $limit, $offset);
 		$members = array_keys($this->_groupMembers($groupDN));
-		if(!$members && empty($posixGroupUsers) && empty($primaryUsers)) {
+		if (!$members && empty($posixGroupUsers) && empty($primaryUsers)) {
 			//in case users could not be retrieved, return empty result set
 			$this->access->connection->writeToCache($cacheKey, []);
 			return [];
@@ -815,29 +815,29 @@ 
 		$groupUsers = array();
 		$isMemberUid = (strtolower($this->access->connection->ldapGroupMemberAssocAttr) === 'memberuid');
 		$attrs = $this->access->userManager->getAttributes(true);
-		foreach($members as $member) {
-			if($isMemberUid) {
+		foreach ($members as $member) {
+			if ($isMemberUid) {
 				//we got uids, need to get their DNs to 'translate' them to user names
 				$filter = $this->access->combineFilterWithAnd(array(
 					str_replace('%uid', $member, $this->access->connection->ldapLoginFilter),
 					$this->access->getFilterPartForUserSearch($search)
 				));
 				$ldap_users = $this->access->fetchListOfUsers($filter, $attrs, 1);
-				if(count($ldap_users) < 1) {
+				if (count($ldap_users) < 1) {
 					continue;
 				}
 				$groupUsers[] = $this->access->dn2username($ldap_users[0]['dn'][0]);
 			} else {
 				//we got DNs, check if we need to filter by search or we can give back all of them
 				if ($search !== '') {
-					if(!$this->access->readAttribute($member,
+					if (!$this->access->readAttribute($member,
 						$this->access->connection->ldapUserDisplayName,
 						$this->access->getFilterPartForUserSearch($search))) {
 						continue;
 					}
 				}
 				// dn2username will also check if the users belong to the allowed base
-				if($ocname = $this->access->dn2username($member)) {
+				if ($ocname = $this->access->dn2username($member)) {
 					$groupUsers[] = $ocname;
 				}
 			}
@@ -861,16 +861,16 @@ 
 	 */
 	public function countUsersInGroup($gid, $search = '') {
 		$cacheKey = 'countUsersInGroup-'.$gid.'-'.$search;
-		if(!$this->enabled || !$this->groupExists($gid)) {
+		if (!$this->enabled || !$this->groupExists($gid)) {
 			return false;
 		}
 		$groupUsers = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($groupUsers)) {
+		if (!is_null($groupUsers)) {
 			return $groupUsers;
 		}
 
 		$groupDN = $this->access->groupname2dn($gid);
-		if(!$groupDN) {
+		if (!$groupDN) {
 			// group couldn't be found, return empty result set
 			$this->access->connection->writeToCache($cacheKey, false);
 			return false;
@@ -878,7 +878,7 @@ 
 
 		$members = array_keys($this->_groupMembers($groupDN));
 		$primaryUserCount = $this->countUsersInPrimaryGroup($groupDN, '');
-		if(!$members && $primaryUserCount === 0) {
+		if (!$members && $primaryUserCount === 0) {
 			//in case users could not be retrieved, return empty result set
 			$this->access->connection->writeToCache($cacheKey, false);
 			return false;
@@ -903,27 +903,27 @@ 
 		//For now this is not important, because the only use of this method
 		//does not supply a search string
 		$groupUsers = array();
-		foreach($members as $member) {
-			if($isMemberUid) {
+		foreach ($members as $member) {
+			if ($isMemberUid) {
 				//we got uids, need to get their DNs to 'translate' them to user names
 				$filter = $this->access->combineFilterWithAnd(array(
 					str_replace('%uid', $member, $this->access->connection->ldapLoginFilter),
 					$this->access->getFilterPartForUserSearch($search)
 				));
 				$ldap_users = $this->access->fetchListOfUsers($filter, 'dn', 1);
-				if(count($ldap_users) < 1) {
+				if (count($ldap_users) < 1) {
 					continue;
 				}
 				$groupUsers[] = $this->access->dn2username($ldap_users[0]);
 			} else {
 				//we need to apply the search filter now
-				if(!$this->access->readAttribute($member,
+				if (!$this->access->readAttribute($member,
 					$this->access->connection->ldapUserDisplayName,
 					$this->access->getFilterPartForUserSearch($search))) {
 					continue;
 				}
 				// dn2username will also check if the users belong to the allowed base
-				if($ocname = $this->access->dn2username($member)) {
+				if ($ocname = $this->access->dn2username($member)) {
 					$groupUsers[] = $ocname;
 				}
 			}
@@ -946,7 +946,7 @@ 
 	 * Returns a list with all groups (used by getGroups)
 	 */
 	protected function getGroupsChunk($search = '', $limit = -1, $offset = 0) {
-		if(!$this->enabled) {
+		if (!$this->enabled) {
 			return array();
 		}
 		$cacheKey = 'getGroups-'.$search.'-'.$limit.'-'.$offset;
@@ -954,13 +954,13 @@ 
 		//Check cache before driving unnecessary searches
 		\OCP\Util::writeLog('user_ldap', 'getGroups '.$cacheKey, \OCP\Util::DEBUG);
 		$ldap_groups = $this->access->connection->getFromCache($cacheKey);
-		if(!is_null($ldap_groups)) {
+		if (!is_null($ldap_groups)) {
 			return $ldap_groups;
 		}
 
 		// if we'd pass -1 to LDAP search, we'd end up in a Protocol
 		// error. With a limit of 0, we get 0 results. So we pass null.
-		if($limit <= 0) {
+		if ($limit <= 0) {
 			$limit = null;
 		}
 		$filter = $this->access->combineFilterWithAnd(array(
@@ -992,7 +992,7 @@ 
 	 * (active directory has a limit of 1000 by default)
 	 */
 	public function getGroups($search = '', $limit = -1, $offset = 0) {
-		if(!$this->enabled) {
+		if (!$this->enabled) {
 			return array();
 		}
 		$search = $this->access->escapeFilterPart($search, true);
@@ -1039,20 +1039,20 @@ 
 	 */
 	public function groupExists($gid) {
 		$groupExists = $this->access->connection->getFromCache('groupExists'.$gid);
-		if(!is_null($groupExists)) {
-			return (bool)$groupExists;
+		if (!is_null($groupExists)) {
+			return (bool) $groupExists;
 		}
 
 		//getting dn, if false the group does not exist. If dn, it may be mapped
 		//only, requires more checking.
 		$dn = $this->access->groupname2dn($gid);
-		if(!$dn) {
+		if (!$dn) {
 			$this->access->connection->writeToCache('groupExists'.$gid, false);
 			return false;
 		}
 
 		//if group really still exists, we will be able to read its objectclass
-		if(!is_array($this->access->readAttribute($dn, ''))) {
+		if (!is_array($this->access->readAttribute($dn, ''))) {
 			$this->access->connection->writeToCache('groupExists'.$gid, false);
 			return false;
 		}
@@ -1070,7 +1070,7 @@ 
 	* compared with \OC\User\Backend::CREATE_USER etc.
 	*/
 	public function implementsActions($actions) {
-		return (bool)(\OC\Group\Backend::COUNT_USERS & $actions);
+		return (bool) (\OC\Group\Backend::COUNT_USERS & $actions);
 	}
 
 	/**

apps/user_ldap/lib/Access.php

Indentation +1819 added lines, -1819 removed lines

@@ -54,1580 +54,1580 @@ 
  * @package OCA\User_LDAP
  */
 class Access extends LDAPUtility implements IUserTools {
-	/**
-	 * @var \OCA\User_LDAP\Connection
-	 */
-	public $connection;
-	/** @var Manager */
-	public $userManager;
-	//never ever check this var directly, always use getPagedSearchResultState
-	protected $pagedSearchedSuccessful;
-
-	/**
-	 * @var string[] $cookies an array of returned Paged Result cookies
-	 */
-	protected $cookies = array();
-
-	/**
-	 * @var string $lastCookie the last cookie returned from a Paged Results
-	 * operation, defaults to an empty string
-	 */
-	protected $lastCookie = '';
-
-	/**
-	 * @var AbstractMapping $userMapper
-	 */
-	protected $userMapper;
-
-	/**
-	* @var AbstractMapping $userMapper
-	*/
-	protected $groupMapper;
+    /**
+     * @var \OCA\User_LDAP\Connection
+     */
+    public $connection;
+    /** @var Manager */
+    public $userManager;
+    //never ever check this var directly, always use getPagedSearchResultState
+    protected $pagedSearchedSuccessful;
+
+    /**
+     * @var string[] $cookies an array of returned Paged Result cookies
+     */
+    protected $cookies = array();
+
+    /**
+     * @var string $lastCookie the last cookie returned from a Paged Results
+     * operation, defaults to an empty string
+     */
+    protected $lastCookie = '';
+
+    /**
+     * @var AbstractMapping $userMapper
+     */
+    protected $userMapper;
+
+    /**
+     * @var AbstractMapping $userMapper
+     */
+    protected $groupMapper;
 	
-	/**
-	 * @var \OCA\User_LDAP\Helper
-	 */
-	private $helper;
-
-	public function __construct(Connection $connection, ILDAPWrapper $ldap,
-		Manager $userManager, Helper $helper) {
-		parent::__construct($ldap);
-		$this->connection = $connection;
-		$this->userManager = $userManager;
-		$this->userManager->setLdapAccess($this);
-		$this->helper = $helper;
-	}
-
-	/**
-	 * sets the User Mapper
-	 * @param AbstractMapping $mapper
-	 */
-	public function setUserMapper(AbstractMapping $mapper) {
-		$this->userMapper = $mapper;
-	}
-
-	/**
-	 * returns the User Mapper
-	 * @throws \Exception
-	 * @return AbstractMapping
-	 */
-	public function getUserMapper() {
-		if(is_null($this->userMapper)) {
-			throw new \Exception('UserMapper was not assigned to this Access instance.');
-		}
-		return $this->userMapper;
-	}
-
-	/**
-	 * sets the Group Mapper
-	 * @param AbstractMapping $mapper
-	 */
-	public function setGroupMapper(AbstractMapping $mapper) {
-		$this->groupMapper = $mapper;
-	}
-
-	/**
-	 * returns the Group Mapper
-	 * @throws \Exception
-	 * @return AbstractMapping
-	 */
-	public function getGroupMapper() {
-		if(is_null($this->groupMapper)) {
-			throw new \Exception('GroupMapper was not assigned to this Access instance.');
-		}
-		return $this->groupMapper;
-	}
-
-	/**
-	 * @return bool
-	 */
-	private function checkConnection() {
-		return ($this->connection instanceof Connection);
-	}
-
-	/**
-	 * returns the Connection instance
-	 * @return \OCA\User_LDAP\Connection
-	 */
-	public function getConnection() {
-		return $this->connection;
-	}
-
-	/**
-	 * reads a given attribute for an LDAP record identified by a DN
-	 * @param string $dn the record in question
-	 * @param string $attr the attribute that shall be retrieved
-	 *        if empty, just check the record's existence
-	 * @param string $filter
-	 * @return array|false an array of values on success or an empty
-	 *          array if $attr is empty, false otherwise
-	 */
-	public function readAttribute($dn, $attr, $filter = 'objectClass=*') {
-		if(!$this->checkConnection()) {
-			\OCP\Util::writeLog('user_ldap',
-				'No LDAP Connector assigned, access impossible for readAttribute.',
-				\OCP\Util::WARN);
-			return false;
-		}
-		$cr = $this->connection->getConnectionResource();
-		if(!$this->ldap->isResource($cr)) {
-			//LDAP not available
-			\OCP\Util::writeLog('user_ldap', 'LDAP resource not available.', \OCP\Util::DEBUG);
-			return false;
-		}
-		//Cancel possibly running Paged Results operation, otherwise we run in
-		//LDAP protocol errors
-		$this->abandonPagedSearch();
-		// openLDAP requires that we init a new Paged Search. Not needed by AD,
-		// but does not hurt either.
-		$pagingSize = intval($this->connection->ldapPagingSize);
-		// 0 won't result in replies, small numbers may leave out groups
-		// (cf. #12306), 500 is default for paging and should work everywhere.
-		$maxResults = $pagingSize > 20 ? $pagingSize : 500;
-		$attr = mb_strtolower($attr, 'UTF-8');
-		// the actual read attribute later may contain parameters on a ranged
-		// request, e.g. member;range=99-199. Depends on server reply.
-		$attrToRead = $attr;
-
-		$values = [];
-		$isRangeRequest = false;
-		do {
-			$result = $this->executeRead($cr, $dn, $attrToRead, $filter, $maxResults);
-			if(is_bool($result)) {
-				// when an exists request was run and it was successful, an empty
-				// array must be returned
-				return $result ? [] : false;
-			}
-
-			if (!$isRangeRequest) {
-				$values = $this->extractAttributeValuesFromResult($result, $attr);
-				if (!empty($values)) {
-					return $values;
-				}
-			}
-
-			$isRangeRequest = false;
-			$result = $this->extractRangeData($result, $attr);
-			if (!empty($result)) {
-				$normalizedResult = $this->extractAttributeValuesFromResult(
-					[ $attr => $result['values'] ],
-					$attr
-				);
-				$values = array_merge($values, $normalizedResult);
-
-				if($result['rangeHigh'] === '*') {
-					// when server replies with * as high range value, there are
-					// no more results left
-					return $values;
-				} else {
-					$low  = $result['rangeHigh'] + 1;
-					$attrToRead = $result['attributeName'] . ';range=' . $low . '-*';
-					$isRangeRequest = true;
-				}
-			}
-		} while($isRangeRequest);
-
-		\OCP\Util::writeLog('user_ldap', 'Requested attribute '.$attr.' not found for '.$dn, \OCP\Util::DEBUG);
-		return false;
-	}
-
-	/**
-	 * Runs an read operation against LDAP
-	 *
-	 * @param resource $cr the LDAP connection
-	 * @param string $dn
-	 * @param string $attribute
-	 * @param string $filter
-	 * @param int $maxResults
-	 * @return array|bool false if there was any error, true if an exists check
-	 *                    was performed and the requested DN found, array with the
-	 *                    returned data on a successful usual operation
-	 */
-	public function executeRead($cr, $dn, $attribute, $filter, $maxResults) {
-		$this->initPagedSearch($filter, array($dn), array($attribute), $maxResults, 0);
-		$dn = $this->helper->DNasBaseParameter($dn);
-		$rr = @$this->invokeLDAPMethod('read', $cr, $dn, $filter, array($attribute));
-		if (!$this->ldap->isResource($rr)) {
-			if ($attribute !== '') {
-				//do not throw this message on userExists check, irritates
-				\OCP\Util::writeLog('user_ldap', 'readAttribute failed for DN ' . $dn, \OCP\Util::DEBUG);
-			}
-			//in case an error occurs , e.g. object does not exist
-			return false;
-		}
-		if ($attribute === '' && ($filter === 'objectclass=*' || $this->invokeLDAPMethod('countEntries', $cr, $rr) === 1)) {
-			\OCP\Util::writeLog('user_ldap', 'readAttribute: ' . $dn . ' found', \OCP\Util::DEBUG);
-			return true;
-		}
-		$er = $this->invokeLDAPMethod('firstEntry', $cr, $rr);
-		if (!$this->ldap->isResource($er)) {
-			//did not match the filter, return false
-			return false;
-		}
-		//LDAP attributes are not case sensitive
-		$result = \OCP\Util::mb_array_change_key_case(
-			$this->invokeLDAPMethod('getAttributes', $cr, $er), MB_CASE_LOWER, 'UTF-8');
-
-		return $result;
-	}
-
-	/**
-	 * Normalizes a result grom getAttributes(), i.e. handles DNs and binary
-	 * data if present.
-	 *
-	 * @param array $result from ILDAPWrapper::getAttributes()
-	 * @param string $attribute the attribute name that was read
-	 * @return string[]
-	 */
-	public function extractAttributeValuesFromResult($result, $attribute) {
-		$values = [];
-		if(isset($result[$attribute]) && $result[$attribute]['count'] > 0) {
-			$lowercaseAttribute = strtolower($attribute);
-			for($i=0;$i<$result[$attribute]['count'];$i++) {
-				if($this->resemblesDN($attribute)) {
-					$values[] = $this->helper->sanitizeDN($result[$attribute][$i]);
-				} elseif($lowercaseAttribute === 'objectguid' || $lowercaseAttribute === 'guid') {
-					$values[] = $this->convertObjectGUID2Str($result[$attribute][$i]);
-				} else {
-					$values[] = $result[$attribute][$i];
-				}
-			}
-		}
-		return $values;
-	}
-
-	/**
-	 * Attempts to find ranged data in a getAttribute results and extracts the
-	 * returned values as well as information on the range and full attribute
-	 * name for further processing.
-	 *
-	 * @param array $result from ILDAPWrapper::getAttributes()
-	 * @param string $attribute the attribute name that was read. Without ";range=…"
-	 * @return array If a range was detected with keys 'values', 'attributeName',
-	 *               'attributeFull' and 'rangeHigh', otherwise empty.
-	 */
-	public function extractRangeData($result, $attribute) {
-		$keys = array_keys($result);
-		foreach($keys as $key) {
-			if($key !== $attribute && strpos($key, $attribute) === 0) {
-				$queryData = explode(';', $key);
-				if(strpos($queryData[1], 'range=') === 0) {
-					$high = substr($queryData[1], 1 + strpos($queryData[1], '-'));
-					$data = [
-						'values' => $result[$key],
-						'attributeName' => $queryData[0],
-						'attributeFull' => $key,
-						'rangeHigh' => $high,
-					];
-					return $data;
-				}
-			}
-		}
-		return [];
-	}
+    /**
+     * @var \OCA\User_LDAP\Helper
+     */
+    private $helper;
+
+    public function __construct(Connection $connection, ILDAPWrapper $ldap,
+        Manager $userManager, Helper $helper) {
+        parent::__construct($ldap);
+        $this->connection = $connection;
+        $this->userManager = $userManager;
+        $this->userManager->setLdapAccess($this);
+        $this->helper = $helper;
+    }
+
+    /**
+     * sets the User Mapper
+     * @param AbstractMapping $mapper
+     */
+    public function setUserMapper(AbstractMapping $mapper) {
+        $this->userMapper = $mapper;
+    }
+
+    /**
+     * returns the User Mapper
+     * @throws \Exception
+     * @return AbstractMapping
+     */
+    public function getUserMapper() {
+        if(is_null($this->userMapper)) {
+            throw new \Exception('UserMapper was not assigned to this Access instance.');
+        }
+        return $this->userMapper;
+    }
+
+    /**
+     * sets the Group Mapper
+     * @param AbstractMapping $mapper
+     */
+    public function setGroupMapper(AbstractMapping $mapper) {
+        $this->groupMapper = $mapper;
+    }
+
+    /**
+     * returns the Group Mapper
+     * @throws \Exception
+     * @return AbstractMapping
+     */
+    public function getGroupMapper() {
+        if(is_null($this->groupMapper)) {
+            throw new \Exception('GroupMapper was not assigned to this Access instance.');
+        }
+        return $this->groupMapper;
+    }
+
+    /**
+     * @return bool
+     */
+    private function checkConnection() {
+        return ($this->connection instanceof Connection);
+    }
+
+    /**
+     * returns the Connection instance
+     * @return \OCA\User_LDAP\Connection
+     */
+    public function getConnection() {
+        return $this->connection;
+    }
+
+    /**
+     * reads a given attribute for an LDAP record identified by a DN
+     * @param string $dn the record in question
+     * @param string $attr the attribute that shall be retrieved
+     *        if empty, just check the record's existence
+     * @param string $filter
+     * @return array|false an array of values on success or an empty
+     *          array if $attr is empty, false otherwise
+     */
+    public function readAttribute($dn, $attr, $filter = 'objectClass=*') {
+        if(!$this->checkConnection()) {
+            \OCP\Util::writeLog('user_ldap',
+                'No LDAP Connector assigned, access impossible for readAttribute.',
+                \OCP\Util::WARN);
+            return false;
+        }
+        $cr = $this->connection->getConnectionResource();
+        if(!$this->ldap->isResource($cr)) {
+            //LDAP not available
+            \OCP\Util::writeLog('user_ldap', 'LDAP resource not available.', \OCP\Util::DEBUG);
+            return false;
+        }
+        //Cancel possibly running Paged Results operation, otherwise we run in
+        //LDAP protocol errors
+        $this->abandonPagedSearch();
+        // openLDAP requires that we init a new Paged Search. Not needed by AD,
+        // but does not hurt either.
+        $pagingSize = intval($this->connection->ldapPagingSize);
+        // 0 won't result in replies, small numbers may leave out groups
+        // (cf. #12306), 500 is default for paging and should work everywhere.
+        $maxResults = $pagingSize > 20 ? $pagingSize : 500;
+        $attr = mb_strtolower($attr, 'UTF-8');
+        // the actual read attribute later may contain parameters on a ranged
+        // request, e.g. member;range=99-199. Depends on server reply.
+        $attrToRead = $attr;
+
+        $values = [];
+        $isRangeRequest = false;
+        do {
+            $result = $this->executeRead($cr, $dn, $attrToRead, $filter, $maxResults);
+            if(is_bool($result)) {
+                // when an exists request was run and it was successful, an empty
+                // array must be returned
+                return $result ? [] : false;
+            }
+
+            if (!$isRangeRequest) {
+                $values = $this->extractAttributeValuesFromResult($result, $attr);
+                if (!empty($values)) {
+                    return $values;
+                }
+            }
+
+            $isRangeRequest = false;
+            $result = $this->extractRangeData($result, $attr);
+            if (!empty($result)) {
+                $normalizedResult = $this->extractAttributeValuesFromResult(
+                    [ $attr => $result['values'] ],
+                    $attr
+                );
+                $values = array_merge($values, $normalizedResult);
+
+                if($result['rangeHigh'] === '*') {
+                    // when server replies with * as high range value, there are
+                    // no more results left
+                    return $values;
+                } else {
+                    $low  = $result['rangeHigh'] + 1;
+                    $attrToRead = $result['attributeName'] . ';range=' . $low . '-*';
+                    $isRangeRequest = true;
+                }
+            }
+        } while($isRangeRequest);
+
+        \OCP\Util::writeLog('user_ldap', 'Requested attribute '.$attr.' not found for '.$dn, \OCP\Util::DEBUG);
+        return false;
+    }
+
+    /**
+     * Runs an read operation against LDAP
+     *
+     * @param resource $cr the LDAP connection
+     * @param string $dn
+     * @param string $attribute
+     * @param string $filter
+     * @param int $maxResults
+     * @return array|bool false if there was any error, true if an exists check
+     *                    was performed and the requested DN found, array with the
+     *                    returned data on a successful usual operation
+     */
+    public function executeRead($cr, $dn, $attribute, $filter, $maxResults) {
+        $this->initPagedSearch($filter, array($dn), array($attribute), $maxResults, 0);
+        $dn = $this->helper->DNasBaseParameter($dn);
+        $rr = @$this->invokeLDAPMethod('read', $cr, $dn, $filter, array($attribute));
+        if (!$this->ldap->isResource($rr)) {
+            if ($attribute !== '') {
+                //do not throw this message on userExists check, irritates
+                \OCP\Util::writeLog('user_ldap', 'readAttribute failed for DN ' . $dn, \OCP\Util::DEBUG);
+            }
+            //in case an error occurs , e.g. object does not exist
+            return false;
+        }
+        if ($attribute === '' && ($filter === 'objectclass=*' || $this->invokeLDAPMethod('countEntries', $cr, $rr) === 1)) {
+            \OCP\Util::writeLog('user_ldap', 'readAttribute: ' . $dn . ' found', \OCP\Util::DEBUG);
+            return true;
+        }
+        $er = $this->invokeLDAPMethod('firstEntry', $cr, $rr);
+        if (!$this->ldap->isResource($er)) {
+            //did not match the filter, return false
+            return false;
+        }
+        //LDAP attributes are not case sensitive
+        $result = \OCP\Util::mb_array_change_key_case(
+            $this->invokeLDAPMethod('getAttributes', $cr, $er), MB_CASE_LOWER, 'UTF-8');
+
+        return $result;
+    }
+
+    /**
+     * Normalizes a result grom getAttributes(), i.e. handles DNs and binary
+     * data if present.
+     *
+     * @param array $result from ILDAPWrapper::getAttributes()
+     * @param string $attribute the attribute name that was read
+     * @return string[]
+     */
+    public function extractAttributeValuesFromResult($result, $attribute) {
+        $values = [];
+        if(isset($result[$attribute]) && $result[$attribute]['count'] > 0) {
+            $lowercaseAttribute = strtolower($attribute);
+            for($i=0;$i<$result[$attribute]['count'];$i++) {
+                if($this->resemblesDN($attribute)) {
+                    $values[] = $this->helper->sanitizeDN($result[$attribute][$i]);
+                } elseif($lowercaseAttribute === 'objectguid' || $lowercaseAttribute === 'guid') {
+                    $values[] = $this->convertObjectGUID2Str($result[$attribute][$i]);
+                } else {
+                    $values[] = $result[$attribute][$i];
+                }
+            }
+        }
+        return $values;
+    }
+
+    /**
+     * Attempts to find ranged data in a getAttribute results and extracts the
+     * returned values as well as information on the range and full attribute
+     * name for further processing.
+     *
+     * @param array $result from ILDAPWrapper::getAttributes()
+     * @param string $attribute the attribute name that was read. Without ";range=…"
+     * @return array If a range was detected with keys 'values', 'attributeName',
+     *               'attributeFull' and 'rangeHigh', otherwise empty.
+     */
+    public function extractRangeData($result, $attribute) {
+        $keys = array_keys($result);
+        foreach($keys as $key) {
+            if($key !== $attribute && strpos($key, $attribute) === 0) {
+                $queryData = explode(';', $key);
+                if(strpos($queryData[1], 'range=') === 0) {
+                    $high = substr($queryData[1], 1 + strpos($queryData[1], '-'));
+                    $data = [
+                        'values' => $result[$key],
+                        'attributeName' => $queryData[0],
+                        'attributeFull' => $key,
+                        'rangeHigh' => $high,
+                    ];
+                    return $data;
+                }
+            }
+        }
+        return [];
+    }
 	
-	/**
-	 * Set password for an LDAP user identified by a DN
-	 *
-	 * @param string $userDN the user in question
-	 * @param string $password the new password
-	 * @return bool
-	 * @throws HintException
-	 * @throws \Exception
-	 */
-	public function setPassword($userDN, $password) {
-		if(intval($this->connection->turnOnPasswordChange) !== 1) {
-			throw new \Exception('LDAP password changes are disabled.');
-		}
-		$cr = $this->connection->getConnectionResource();
-		if(!$this->ldap->isResource($cr)) {
-			//LDAP not available
-			\OCP\Util::writeLog('user_ldap', 'LDAP resource not available.', \OCP\Util::DEBUG);
-			return false;
-		}
-		try {
-			return @$this->invokeLDAPMethod('modReplace', $cr, $userDN, $password);
-		} catch(ConstraintViolationException $e) {
-			throw new HintException('Password change rejected.', \OC::$server->getL10N('user_ldap')->t('Password change rejected. Hint: ').$e->getMessage(), $e->getCode());
-		}
-	}
-
-	/**
-	 * checks whether the given attributes value is probably a DN
-	 * @param string $attr the attribute in question
-	 * @return boolean if so true, otherwise false
-	 */
-	private function resemblesDN($attr) {
-		$resemblingAttributes = array(
-			'dn',
-			'uniquemember',
-			'member',
-			// memberOf is an "operational" attribute, without a definition in any RFC
-			'memberof'
-		);
-		return in_array($attr, $resemblingAttributes);
-	}
-
-	/**
-	 * checks whether the given string is probably a DN
-	 * @param string $string
-	 * @return boolean
-	 */
-	public function stringResemblesDN($string) {
-		$r = $this->ldap->explodeDN($string, 0);
-		// if exploding a DN succeeds and does not end up in
-		// an empty array except for $r[count] being 0.
-		return (is_array($r) && count($r) > 1);
-	}
-
-	/**
-	 * returns a DN-string that is cleaned from not domain parts, e.g.
-	 * cn=foo,cn=bar,dc=foobar,dc=server,dc=org
-	 * becomes dc=foobar,dc=server,dc=org
-	 * @param string $dn
-	 * @return string
-	 */
-	public function getDomainDNFromDN($dn) {
-		$allParts = $this->ldap->explodeDN($dn, 0);
-		if($allParts === false) {
-			//not a valid DN
-			return '';
-		}
-		$domainParts = array();
-		$dcFound = false;
-		foreach($allParts as $part) {
-			if(!$dcFound && strpos($part, 'dc=') === 0) {
-				$dcFound = true;
-			}
-			if($dcFound) {
-				$domainParts[] = $part;
-			}
-		}
-		$domainDN = implode(',', $domainParts);
-		return $domainDN;
-	}
-
-	/**
-	 * returns the LDAP DN for the given internal Nextcloud name of the group
-	 * @param string $name the Nextcloud name in question
-	 * @return string|false LDAP DN on success, otherwise false
-	 */
-	public function groupname2dn($name) {
-		return $this->groupMapper->getDNByName($name);
-	}
-
-	/**
-	 * returns the LDAP DN for the given internal Nextcloud name of the user
-	 * @param string $name the Nextcloud name in question
-	 * @return string|false with the LDAP DN on success, otherwise false
-	 */
-	public function username2dn($name) {
-		$fdn = $this->userMapper->getDNByName($name);
-
-		//Check whether the DN belongs to the Base, to avoid issues on multi-
-		//server setups
-		if(is_string($fdn) && $this->isDNPartOfBase($fdn, $this->connection->ldapBaseUsers)) {
-			return $fdn;
-		}
-
-		return false;
-	}
-
-	/**
-	 * returns the internal Nextcloud name for the given LDAP DN of the group, false on DN outside of search DN or failure
-	 * @param string $fdn the dn of the group object
-	 * @param string $ldapName optional, the display name of the object
-	 * @return string|false with the name to use in Nextcloud, false on DN outside of search DN
-	 */
-	public function dn2groupname($fdn, $ldapName = null) {
-		//To avoid bypassing the base DN settings under certain circumstances
-		//with the group support, check whether the provided DN matches one of
-		//the given Bases
-		if(!$this->isDNPartOfBase($fdn, $this->connection->ldapBaseGroups)) {
-			return false;
-		}
-
-		return $this->dn2ocname($fdn, $ldapName, false);
-	}
-
-	/**
-	 * accepts an array of group DNs and tests whether they match the user
-	 * filter by doing read operations against the group entries. Returns an
-	 * array of DNs that match the filter.
-	 *
-	 * @param string[] $groupDNs
-	 * @return string[]
-	 */
-	public function groupsMatchFilter($groupDNs) {
-		$validGroupDNs = [];
-		foreach($groupDNs as $dn) {
-			$cacheKey = 'groupsMatchFilter-'.$dn;
-			$groupMatchFilter = $this->connection->getFromCache($cacheKey);
-			if(!is_null($groupMatchFilter)) {
-				if($groupMatchFilter) {
-					$validGroupDNs[] = $dn;
-				}
-				continue;
-			}
-
-			// Check the base DN first. If this is not met already, we don't
-			// need to ask the server at all.
-			if(!$this->isDNPartOfBase($dn, $this->connection->ldapBaseGroups)) {
-				$this->connection->writeToCache($cacheKey, false);
-				continue;
-			}
-
-			$result = $this->readAttribute($dn, 'cn', $this->connection->ldapGroupFilter);
-			if(is_array($result)) {
-				$this->connection->writeToCache($cacheKey, true);
-				$validGroupDNs[] = $dn;
-			} else {
-				$this->connection->writeToCache($cacheKey, false);
-			}
-
-		}
-		return $validGroupDNs;
-	}
-
-	/**
-	 * returns the internal Nextcloud name for the given LDAP DN of the user, false on DN outside of search DN or failure
-	 * @param string $dn the dn of the user object
-	 * @param string $ldapName optional, the display name of the object
-	 * @return string|false with with the name to use in Nextcloud
-	 */
-	public function dn2username($fdn, $ldapName = null) {
-		//To avoid bypassing the base DN settings under certain circumstances
-		//with the group support, check whether the provided DN matches one of
-		//the given Bases
-		if(!$this->isDNPartOfBase($fdn, $this->connection->ldapBaseUsers)) {
-			return false;
-		}
-
-		return $this->dn2ocname($fdn, $ldapName, true);
-	}
-
-	/**
-	 * returns an internal Nextcloud name for the given LDAP DN, false on DN outside of search DN
-	 * @param string $dn the dn of the user object
-	 * @param string $ldapName optional, the display name of the object
-	 * @param bool $isUser optional, whether it is a user object (otherwise group assumed)
-	 * @return string|false with with the name to use in Nextcloud
-	 */
-	public function dn2ocname($fdn, $ldapName = null, $isUser = true) {
-		if($isUser) {
-			$mapper = $this->getUserMapper();
-			$nameAttribute = $this->connection->ldapUserDisplayName;
-		} else {
-			$mapper = $this->getGroupMapper();
-			$nameAttribute = $this->connection->ldapGroupDisplayName;
-		}
-
-		//let's try to retrieve the Nextcloud name from the mappings table
-		$ocName = $mapper->getNameByDN($fdn);
-		if(is_string($ocName)) {
-			return $ocName;
-		}
-
-		//second try: get the UUID and check if it is known. Then, update the DN and return the name.
-		$uuid = $this->getUUID($fdn, $isUser);
-		if(is_string($uuid)) {
-			$ocName = $mapper->getNameByUUID($uuid);
-			if(is_string($ocName)) {
-				$mapper->setDNbyUUID($fdn, $uuid);
-				return $ocName;
-			}
-		} else {
-			//If the UUID can't be detected something is foul.
-			\OCP\Util::writeLog('user_ldap', 'Cannot determine UUID for '.$fdn.'. Skipping.', \OCP\Util::INFO);
-			return false;
-		}
-
-		if(is_null($ldapName)) {
-			$ldapName = $this->readAttribute($fdn, $nameAttribute);
-			if(!isset($ldapName[0]) && empty($ldapName[0])) {
-				\OCP\Util::writeLog('user_ldap', 'No or empty name for '.$fdn.'.', \OCP\Util::INFO);
-				return false;
-			}
-			$ldapName = $ldapName[0];
-		}
-
-		if($isUser) {
-			$usernameAttribute = strval($this->connection->ldapExpertUsernameAttr);
-			if ($usernameAttribute !== '') {
-				$username = $this->readAttribute($fdn, $usernameAttribute);
-				$username = $username[0];
-			} else {
-				$username = $uuid;
-			}
-			$intName = $this->sanitizeUsername($username);
-		} else {
-			$intName = $ldapName;
-		}
-
-		//a new user/group! Add it only if it doesn't conflict with other backend's users or existing groups
-		//disabling Cache is required to avoid that the new user is cached as not-existing in fooExists check
-		//NOTE: mind, disabling cache affects only this instance! Using it
-		// outside of core user management will still cache the user as non-existing.
-		$originalTTL = $this->connection->ldapCacheTTL;
-		$this->connection->setConfiguration(array('ldapCacheTTL' => 0));
-		if(($isUser && !\OCP\User::userExists($intName))
-			|| (!$isUser && !\OC::$server->getGroupManager()->groupExists($intName))) {
-			if($mapper->map($fdn, $intName, $uuid)) {
-				$this->connection->setConfiguration(array('ldapCacheTTL' => $originalTTL));
-				return $intName;
-			}
-		}
-		$this->connection->setConfiguration(array('ldapCacheTTL' => $originalTTL));
-
-		$altName = $this->createAltInternalOwnCloudName($intName, $isUser);
-		if(is_string($altName) && $mapper->map($fdn, $altName, $uuid)) {
-			return $altName;
-		}
-
-		//if everything else did not help..
-		\OCP\Util::writeLog('user_ldap', 'Could not create unique name for '.$fdn.'.', \OCP\Util::INFO);
-		return false;
-	}
-
-	/**
-	 * gives back the user names as they are used ownClod internally
-	 * @param array $ldapUsers as returned by fetchList()
-	 * @return array an array with the user names to use in Nextcloud
-	 *
-	 * gives back the user names as they are used ownClod internally
-	 */
-	public function nextcloudUserNames($ldapUsers) {
-		return $this->ldap2NextcloudNames($ldapUsers, true);
-	}
-
-	/**
-	 * gives back the group names as they are used ownClod internally
-	 * @param array $ldapGroups as returned by fetchList()
-	 * @return array an array with the group names to use in Nextcloud
-	 *
-	 * gives back the group names as they are used ownClod internally
-	 */
-	public function nextcloudGroupNames($ldapGroups) {
-		return $this->ldap2NextcloudNames($ldapGroups, false);
-	}
-
-	/**
-	 * @param array $ldapObjects as returned by fetchList()
-	 * @param bool $isUsers
-	 * @return array
-	 */
-	private function ldap2NextcloudNames($ldapObjects, $isUsers) {
-		if($isUsers) {
-			$nameAttribute = $this->connection->ldapUserDisplayName;
-			$sndAttribute  = $this->connection->ldapUserDisplayName2;
-		} else {
-			$nameAttribute = $this->connection->ldapGroupDisplayName;
-		}
-		$nextcloudNames = array();
-
-		foreach($ldapObjects as $ldapObject) {
-			$nameByLDAP = null;
-			if(    isset($ldapObject[$nameAttribute])
-				&& is_array($ldapObject[$nameAttribute])
-				&& isset($ldapObject[$nameAttribute][0])
-			) {
-				// might be set, but not necessarily. if so, we use it.
-				$nameByLDAP = $ldapObject[$nameAttribute][0];
-			}
-
-			$ncName = $this->dn2ocname($ldapObject['dn'][0], $nameByLDAP, $isUsers);
-			if($ncName) {
-				$nextcloudNames[] = $ncName;
-				if($isUsers) {
-					//cache the user names so it does not need to be retrieved
-					//again later (e.g. sharing dialogue).
-					if(is_null($nameByLDAP)) {
-						continue;
-					}
-					$sndName = isset($ldapObject[$sndAttribute][0])
-						? $ldapObject[$sndAttribute][0] : '';
-					$this->cacheUserDisplayName($ncName, $nameByLDAP, $sndName);
-				}
-			}
-		}
-		return $nextcloudNames;
-	}
-
-	/**
-	 * caches the user display name
-	 * @param string $ocName the internal Nextcloud username
-	 * @param string|false $home the home directory path
-	 */
-	public function cacheUserHome($ocName, $home) {
-		$cacheKey = 'getHome'.$ocName;
-		$this->connection->writeToCache($cacheKey, $home);
-	}
-
-	/**
-	 * caches a user as existing
-	 * @param string $ocName the internal Nextcloud username
-	 */
-	public function cacheUserExists($ocName) {
-		$this->connection->writeToCache('userExists'.$ocName, true);
-	}
-
-	/**
-	 * caches the user display name
-	 * @param string $ocName the internal Nextcloud username
-	 * @param string $displayName the display name
-	 * @param string $displayName2 the second display name
-	 */
-	public function cacheUserDisplayName($ocName, $displayName, $displayName2 = '') {
-		$user = $this->userManager->get($ocName);
-		if($user === null) {
-			return;
-		}
-		$displayName = $user->composeAndStoreDisplayName($displayName, $displayName2);
-		$cacheKeyTrunk = 'getDisplayName';
-		$this->connection->writeToCache($cacheKeyTrunk.$ocName, $displayName);
-	}
-
-	/**
-	 * creates a unique name for internal Nextcloud use for users. Don't call it directly.
-	 * @param string $name the display name of the object
-	 * @return string|false with with the name to use in Nextcloud or false if unsuccessful
-	 *
-	 * Instead of using this method directly, call
-	 * createAltInternalOwnCloudName($name, true)
-	 */
-	private function _createAltInternalOwnCloudNameForUsers($name) {
-		$attempts = 0;
-		//while loop is just a precaution. If a name is not generated within
-		//20 attempts, something else is very wrong. Avoids infinite loop.
-		while($attempts < 20){
-			$altName = $name . '_' . rand(1000,9999);
-			if(!\OCP\User::userExists($altName)) {
-				return $altName;
-			}
-			$attempts++;
-		}
-		return false;
-	}
-
-	/**
-	 * creates a unique name for internal Nextcloud use for groups. Don't call it directly.
-	 * @param string $name the display name of the object
-	 * @return string|false with with the name to use in Nextcloud or false if unsuccessful.
-	 *
-	 * Instead of using this method directly, call
-	 * createAltInternalOwnCloudName($name, false)
-	 *
-	 * Group names are also used as display names, so we do a sequential
-	 * numbering, e.g. Developers_42 when there are 41 other groups called
-	 * "Developers"
-	 */
-	private function _createAltInternalOwnCloudNameForGroups($name) {
-		$usedNames = $this->groupMapper->getNamesBySearch($name, "", '_%');
-		if(!($usedNames) || count($usedNames) === 0) {
-			$lastNo = 1; //will become name_2
-		} else {
-			natsort($usedNames);
-			$lastName = array_pop($usedNames);
-			$lastNo = intval(substr($lastName, strrpos($lastName, '_') + 1));
-		}
-		$altName = $name.'_'.strval($lastNo+1);
-		unset($usedNames);
-
-		$attempts = 1;
-		while($attempts < 21){
-			// Check to be really sure it is unique
-			// while loop is just a precaution. If a name is not generated within
-			// 20 attempts, something else is very wrong. Avoids infinite loop.
-			if(!\OC::$server->getGroupManager()->groupExists($altName)) {
-				return $altName;
-			}
-			$altName = $name . '_' . ($lastNo + $attempts);
-			$attempts++;
-		}
-		return false;
-	}
-
-	/**
-	 * creates a unique name for internal Nextcloud use.
-	 * @param string $name the display name of the object
-	 * @param boolean $isUser whether name should be created for a user (true) or a group (false)
-	 * @return string|false with with the name to use in Nextcloud or false if unsuccessful
-	 */
-	private function createAltInternalOwnCloudName($name, $isUser) {
-		$originalTTL = $this->connection->ldapCacheTTL;
-		$this->connection->setConfiguration(array('ldapCacheTTL' => 0));
-		if($isUser) {
-			$altName = $this->_createAltInternalOwnCloudNameForUsers($name);
-		} else {
-			$altName = $this->_createAltInternalOwnCloudNameForGroups($name);
-		}
-		$this->connection->setConfiguration(array('ldapCacheTTL' => $originalTTL));
-
-		return $altName;
-	}
-
-	/**
-	 * fetches a list of users according to a provided loginName and utilizing
-	 * the login filter.
-	 *
-	 * @param string $loginName
-	 * @param array $attributes optional, list of attributes to read
-	 * @return array
-	 */
-	public function fetchUsersByLoginName($loginName, $attributes = array('dn')) {
-		$loginName = $this->escapeFilterPart($loginName);
-		$filter = str_replace('%uid', $loginName, $this->connection->ldapLoginFilter);
-		$users = $this->fetchListOfUsers($filter, $attributes);
-		return $users;
-	}
-
-	/**
-	 * counts the number of users according to a provided loginName and
-	 * utilizing the login filter.
-	 *
-	 * @param string $loginName
-	 * @return array
-	 */
-	public function countUsersByLoginName($loginName) {
-		$loginName = $this->escapeFilterPart($loginName);
-		$filter = str_replace('%uid', $loginName, $this->connection->ldapLoginFilter);
-		$users = $this->countUsers($filter);
-		return $users;
-	}
-
-	/**
-	 * @param string $filter
-	 * @param string|string[] $attr
-	 * @param int $limit
-	 * @param int $offset
-	 * @return array
-	 */
-	public function fetchListOfUsers($filter, $attr, $limit = null, $offset = null) {
-		$ldapRecords = $this->searchUsers($filter, $attr, $limit, $offset);
-		$this->batchApplyUserAttributes($ldapRecords);
-		return $this->fetchList($ldapRecords, (count($attr) > 1));
-	}
-
-	/**
-	 * provided with an array of LDAP user records the method will fetch the
-	 * user object and requests it to process the freshly fetched attributes and
-	 * and their values
-	 * @param array $ldapRecords
-	 */
-	public function batchApplyUserAttributes(array $ldapRecords){
-		$displayNameAttribute = strtolower($this->connection->ldapUserDisplayName);
-		foreach($ldapRecords as $userRecord) {
-			if(!isset($userRecord[$displayNameAttribute])) {
-				// displayName is obligatory
-				continue;
-			}
-			$ocName  = $this->dn2ocname($userRecord['dn'][0]);
-			if($ocName === false) {
-				continue;
-			}
-			$this->cacheUserExists($ocName);
-			$user = $this->userManager->get($ocName);
-			if($user instanceof OfflineUser) {
-				$user->unmark();
-				$user = $this->userManager->get($ocName);
-			}
-			if ($user !== null) {
-				$user->processAttributes($userRecord);
-			} else {
-				\OC::$server->getLogger()->debug(
-					"The ldap user manager returned null for $ocName",
-					['app'=>'user_ldap']
-				);
-			}
-		}
-	}
-
-	/**
-	 * @param string $filter
-	 * @param string|string[] $attr
-	 * @param int $limit
-	 * @param int $offset
-	 * @return array
-	 */
-	public function fetchListOfGroups($filter, $attr, $limit = null, $offset = null) {
-		return $this->fetchList($this->searchGroups($filter, $attr, $limit, $offset), (count($attr) > 1));
-	}
-
-	/**
-	 * @param array $list
-	 * @param bool $manyAttributes
-	 * @return array
-	 */
-	private function fetchList($list, $manyAttributes) {
-		if(is_array($list)) {
-			if($manyAttributes) {
-				return $list;
-			} else {
-				$list = array_reduce($list, function($carry, $item) {
-					$attribute = array_keys($item)[0];
-					$carry[] = $item[$attribute][0];
-					return $carry;
-				}, array());
-				return array_unique($list, SORT_LOCALE_STRING);
-			}
-		}
-
-		//error cause actually, maybe throw an exception in future.
-		return array();
-	}
-
-	/**
-	 * executes an LDAP search, optimized for Users
-	 * @param string $filter the LDAP filter for the search
-	 * @param string|string[] $attr optional, when a certain attribute shall be filtered out
-	 * @param integer $limit
-	 * @param integer $offset
-	 * @return array with the search result
-	 *
-	 * Executes an LDAP search
-	 */
-	public function searchUsers($filter, $attr = null, $limit = null, $offset = null) {
-		return $this->search($filter, $this->connection->ldapBaseUsers, $attr, $limit, $offset);
-	}
-
-	/**
-	 * @param string $filter
-	 * @param string|string[] $attr
-	 * @param int $limit
-	 * @param int $offset
-	 * @return false|int
-	 */
-	public function countUsers($filter, $attr = array('dn'), $limit = null, $offset = null) {
-		return $this->count($filter, $this->connection->ldapBaseUsers, $attr, $limit, $offset);
-	}
-
-	/**
-	 * executes an LDAP search, optimized for Groups
-	 * @param string $filter the LDAP filter for the search
-	 * @param string|string[] $attr optional, when a certain attribute shall be filtered out
-	 * @param integer $limit
-	 * @param integer $offset
-	 * @return array with the search result
-	 *
-	 * Executes an LDAP search
-	 */
-	public function searchGroups($filter, $attr = null, $limit = null, $offset = null) {
-		return $this->search($filter, $this->connection->ldapBaseGroups, $attr, $limit, $offset);
-	}
-
-	/**
-	 * returns the number of available groups
-	 * @param string $filter the LDAP search filter
-	 * @param string[] $attr optional
-	 * @param int|null $limit
-	 * @param int|null $offset
-	 * @return int|bool
-	 */
-	public function countGroups($filter, $attr = array('dn'), $limit = null, $offset = null) {
-		return $this->count($filter, $this->connection->ldapBaseGroups, $attr, $limit, $offset);
-	}
-
-	/**
-	 * returns the number of available objects on the base DN
-	 *
-	 * @param int|null $limit
-	 * @param int|null $offset
-	 * @return int|bool
-	 */
-	public function countObjects($limit = null, $offset = null) {
-		return $this->count('objectclass=*', $this->connection->ldapBase, array('dn'), $limit, $offset);
-	}
-
-	/**
-	 * Returns the LDAP handler
-	 * @throws \OC\ServerNotAvailableException
-	 */
-
-	/**
-	 * @return mixed
-	 * @throws \OC\ServerNotAvailableException
-	 */
-	private function invokeLDAPMethod() {
-		$arguments = func_get_args();
-		$command = array_shift($arguments);
-		$cr = array_shift($arguments);
-		if (!method_exists($this->ldap, $command)) {
-			return null;
-		}
-		array_unshift($arguments, $cr);
-		// php no longer supports call-time pass-by-reference
-		// thus cannot support controlPagedResultResponse as the third argument
-		// is a reference
-		$doMethod = function () use ($command, &$arguments) {
-			if ($command == 'controlPagedResultResponse') {
-				throw new \InvalidArgumentException('Invoker does not support controlPagedResultResponse, call LDAP Wrapper directly instead.');
-			} else {
-				return call_user_func_array(array($this->ldap, $command), $arguments);
-			}
-		};
-		try {
-			$ret = $doMethod();
-		} catch (ServerNotAvailableException $e) {
-			/* Server connection lost, attempt to reestablish it
+    /**
+     * Set password for an LDAP user identified by a DN
+     *
+     * @param string $userDN the user in question
+     * @param string $password the new password
+     * @return bool
+     * @throws HintException
+     * @throws \Exception
+     */
+    public function setPassword($userDN, $password) {
+        if(intval($this->connection->turnOnPasswordChange) !== 1) {
+            throw new \Exception('LDAP password changes are disabled.');
+        }
+        $cr = $this->connection->getConnectionResource();
+        if(!$this->ldap->isResource($cr)) {
+            //LDAP not available
+            \OCP\Util::writeLog('user_ldap', 'LDAP resource not available.', \OCP\Util::DEBUG);
+            return false;
+        }
+        try {
+            return @$this->invokeLDAPMethod('modReplace', $cr, $userDN, $password);
+        } catch(ConstraintViolationException $e) {
+            throw new HintException('Password change rejected.', \OC::$server->getL10N('user_ldap')->t('Password change rejected. Hint: ').$e->getMessage(), $e->getCode());
+        }
+    }
+
+    /**
+     * checks whether the given attributes value is probably a DN
+     * @param string $attr the attribute in question
+     * @return boolean if so true, otherwise false
+     */
+    private function resemblesDN($attr) {
+        $resemblingAttributes = array(
+            'dn',
+            'uniquemember',
+            'member',
+            // memberOf is an "operational" attribute, without a definition in any RFC
+            'memberof'
+        );
+        return in_array($attr, $resemblingAttributes);
+    }
+
+    /**
+     * checks whether the given string is probably a DN
+     * @param string $string
+     * @return boolean
+     */
+    public function stringResemblesDN($string) {
+        $r = $this->ldap->explodeDN($string, 0);
+        // if exploding a DN succeeds and does not end up in
+        // an empty array except for $r[count] being 0.
+        return (is_array($r) && count($r) > 1);
+    }
+
+    /**
+     * returns a DN-string that is cleaned from not domain parts, e.g.
+     * cn=foo,cn=bar,dc=foobar,dc=server,dc=org
+     * becomes dc=foobar,dc=server,dc=org
+     * @param string $dn
+     * @return string
+     */
+    public function getDomainDNFromDN($dn) {
+        $allParts = $this->ldap->explodeDN($dn, 0);
+        if($allParts === false) {
+            //not a valid DN
+            return '';
+        }
+        $domainParts = array();
+        $dcFound = false;
+        foreach($allParts as $part) {
+            if(!$dcFound && strpos($part, 'dc=') === 0) {
+                $dcFound = true;
+            }
+            if($dcFound) {
+                $domainParts[] = $part;
+            }
+        }
+        $domainDN = implode(',', $domainParts);
+        return $domainDN;
+    }
+
+    /**
+     * returns the LDAP DN for the given internal Nextcloud name of the group
+     * @param string $name the Nextcloud name in question
+     * @return string|false LDAP DN on success, otherwise false
+     */
+    public function groupname2dn($name) {
+        return $this->groupMapper->getDNByName($name);
+    }
+
+    /**
+     * returns the LDAP DN for the given internal Nextcloud name of the user
+     * @param string $name the Nextcloud name in question
+     * @return string|false with the LDAP DN on success, otherwise false
+     */
+    public function username2dn($name) {
+        $fdn = $this->userMapper->getDNByName($name);
+
+        //Check whether the DN belongs to the Base, to avoid issues on multi-
+        //server setups
+        if(is_string($fdn) && $this->isDNPartOfBase($fdn, $this->connection->ldapBaseUsers)) {
+            return $fdn;
+        }
+
+        return false;
+    }
+
+    /**
+     * returns the internal Nextcloud name for the given LDAP DN of the group, false on DN outside of search DN or failure
+     * @param string $fdn the dn of the group object
+     * @param string $ldapName optional, the display name of the object
+     * @return string|false with the name to use in Nextcloud, false on DN outside of search DN
+     */
+    public function dn2groupname($fdn, $ldapName = null) {
+        //To avoid bypassing the base DN settings under certain circumstances
+        //with the group support, check whether the provided DN matches one of
+        //the given Bases
+        if(!$this->isDNPartOfBase($fdn, $this->connection->ldapBaseGroups)) {
+            return false;
+        }
+
+        return $this->dn2ocname($fdn, $ldapName, false);
+    }
+
+    /**
+     * accepts an array of group DNs and tests whether they match the user
+     * filter by doing read operations against the group entries. Returns an
+     * array of DNs that match the filter.
+     *
+     * @param string[] $groupDNs
+     * @return string[]
+     */
+    public function groupsMatchFilter($groupDNs) {
+        $validGroupDNs = [];
+        foreach($groupDNs as $dn) {
+            $cacheKey = 'groupsMatchFilter-'.$dn;
+            $groupMatchFilter = $this->connection->getFromCache($cacheKey);
+            if(!is_null($groupMatchFilter)) {
+                if($groupMatchFilter) {
+                    $validGroupDNs[] = $dn;
+                }
+                continue;
+            }
+
+            // Check the base DN first. If this is not met already, we don't
+            // need to ask the server at all.
+            if(!$this->isDNPartOfBase($dn, $this->connection->ldapBaseGroups)) {
+                $this->connection->writeToCache($cacheKey, false);
+                continue;
+            }
+
+            $result = $this->readAttribute($dn, 'cn', $this->connection->ldapGroupFilter);
+            if(is_array($result)) {
+                $this->connection->writeToCache($cacheKey, true);
+                $validGroupDNs[] = $dn;
+            } else {
+                $this->connection->writeToCache($cacheKey, false);
+            }
+
+        }
+        return $validGroupDNs;
+    }
+
+    /**
+     * returns the internal Nextcloud name for the given LDAP DN of the user, false on DN outside of search DN or failure
+     * @param string $dn the dn of the user object
+     * @param string $ldapName optional, the display name of the object
+     * @return string|false with with the name to use in Nextcloud
+     */
+    public function dn2username($fdn, $ldapName = null) {
+        //To avoid bypassing the base DN settings under certain circumstances
+        //with the group support, check whether the provided DN matches one of
+        //the given Bases
+        if(!$this->isDNPartOfBase($fdn, $this->connection->ldapBaseUsers)) {
+            return false;
+        }
+
+        return $this->dn2ocname($fdn, $ldapName, true);
+    }
+
+    /**
+     * returns an internal Nextcloud name for the given LDAP DN, false on DN outside of search DN
+     * @param string $dn the dn of the user object
+     * @param string $ldapName optional, the display name of the object
+     * @param bool $isUser optional, whether it is a user object (otherwise group assumed)
+     * @return string|false with with the name to use in Nextcloud
+     */
+    public function dn2ocname($fdn, $ldapName = null, $isUser = true) {
+        if($isUser) {
+            $mapper = $this->getUserMapper();
+            $nameAttribute = $this->connection->ldapUserDisplayName;
+        } else {
+            $mapper = $this->getGroupMapper();
+            $nameAttribute = $this->connection->ldapGroupDisplayName;
+        }
+
+        //let's try to retrieve the Nextcloud name from the mappings table
+        $ocName = $mapper->getNameByDN($fdn);
+        if(is_string($ocName)) {
+            return $ocName;
+        }
+
+        //second try: get the UUID and check if it is known. Then, update the DN and return the name.
+        $uuid = $this->getUUID($fdn, $isUser);
+        if(is_string($uuid)) {
+            $ocName = $mapper->getNameByUUID($uuid);
+            if(is_string($ocName)) {
+                $mapper->setDNbyUUID($fdn, $uuid);
+                return $ocName;
+            }
+        } else {
+            //If the UUID can't be detected something is foul.
+            \OCP\Util::writeLog('user_ldap', 'Cannot determine UUID for '.$fdn.'. Skipping.', \OCP\Util::INFO);
+            return false;
+        }
+
+        if(is_null($ldapName)) {
+            $ldapName = $this->readAttribute($fdn, $nameAttribute);
+            if(!isset($ldapName[0]) && empty($ldapName[0])) {
+                \OCP\Util::writeLog('user_ldap', 'No or empty name for '.$fdn.'.', \OCP\Util::INFO);
+                return false;
+            }
+            $ldapName = $ldapName[0];
+        }
+
+        if($isUser) {
+            $usernameAttribute = strval($this->connection->ldapExpertUsernameAttr);
+            if ($usernameAttribute !== '') {
+                $username = $this->readAttribute($fdn, $usernameAttribute);
+                $username = $username[0];
+            } else {
+                $username = $uuid;
+            }
+            $intName = $this->sanitizeUsername($username);
+        } else {
+            $intName = $ldapName;
+        }
+
+        //a new user/group! Add it only if it doesn't conflict with other backend's users or existing groups
+        //disabling Cache is required to avoid that the new user is cached as not-existing in fooExists check
+        //NOTE: mind, disabling cache affects only this instance! Using it
+        // outside of core user management will still cache the user as non-existing.
+        $originalTTL = $this->connection->ldapCacheTTL;
+        $this->connection->setConfiguration(array('ldapCacheTTL' => 0));
+        if(($isUser && !\OCP\User::userExists($intName))
+            || (!$isUser && !\OC::$server->getGroupManager()->groupExists($intName))) {
+            if($mapper->map($fdn, $intName, $uuid)) {
+                $this->connection->setConfiguration(array('ldapCacheTTL' => $originalTTL));
+                return $intName;
+            }
+        }
+        $this->connection->setConfiguration(array('ldapCacheTTL' => $originalTTL));
+
+        $altName = $this->createAltInternalOwnCloudName($intName, $isUser);
+        if(is_string($altName) && $mapper->map($fdn, $altName, $uuid)) {
+            return $altName;
+        }
+
+        //if everything else did not help..
+        \OCP\Util::writeLog('user_ldap', 'Could not create unique name for '.$fdn.'.', \OCP\Util::INFO);
+        return false;
+    }
+
+    /**
+     * gives back the user names as they are used ownClod internally
+     * @param array $ldapUsers as returned by fetchList()
+     * @return array an array with the user names to use in Nextcloud
+     *
+     * gives back the user names as they are used ownClod internally
+     */
+    public function nextcloudUserNames($ldapUsers) {
+        return $this->ldap2NextcloudNames($ldapUsers, true);
+    }
+
+    /**
+     * gives back the group names as they are used ownClod internally
+     * @param array $ldapGroups as returned by fetchList()
+     * @return array an array with the group names to use in Nextcloud
+     *
+     * gives back the group names as they are used ownClod internally
+     */
+    public function nextcloudGroupNames($ldapGroups) {
+        return $this->ldap2NextcloudNames($ldapGroups, false);
+    }
+
+    /**
+     * @param array $ldapObjects as returned by fetchList()
+     * @param bool $isUsers
+     * @return array
+     */
+    private function ldap2NextcloudNames($ldapObjects, $isUsers) {
+        if($isUsers) {
+            $nameAttribute = $this->connection->ldapUserDisplayName;
+            $sndAttribute  = $this->connection->ldapUserDisplayName2;
+        } else {
+            $nameAttribute = $this->connection->ldapGroupDisplayName;
+        }
+        $nextcloudNames = array();
+
+        foreach($ldapObjects as $ldapObject) {
+            $nameByLDAP = null;
+            if(    isset($ldapObject[$nameAttribute])
+                && is_array($ldapObject[$nameAttribute])
+                && isset($ldapObject[$nameAttribute][0])
+            ) {
+                // might be set, but not necessarily. if so, we use it.
+                $nameByLDAP = $ldapObject[$nameAttribute][0];
+            }
+
+            $ncName = $this->dn2ocname($ldapObject['dn'][0], $nameByLDAP, $isUsers);
+            if($ncName) {
+                $nextcloudNames[] = $ncName;
+                if($isUsers) {
+                    //cache the user names so it does not need to be retrieved
+                    //again later (e.g. sharing dialogue).
+                    if(is_null($nameByLDAP)) {
+                        continue;
+                    }
+                    $sndName = isset($ldapObject[$sndAttribute][0])
+                        ? $ldapObject[$sndAttribute][0] : '';
+                    $this->cacheUserDisplayName($ncName, $nameByLDAP, $sndName);
+                }
+            }
+        }
+        return $nextcloudNames;
+    }
+
+    /**
+     * caches the user display name
+     * @param string $ocName the internal Nextcloud username
+     * @param string|false $home the home directory path
+     */
+    public function cacheUserHome($ocName, $home) {
+        $cacheKey = 'getHome'.$ocName;
+        $this->connection->writeToCache($cacheKey, $home);
+    }
+
+    /**
+     * caches a user as existing
+     * @param string $ocName the internal Nextcloud username
+     */
+    public function cacheUserExists($ocName) {
+        $this->connection->writeToCache('userExists'.$ocName, true);
+    }
+
+    /**
+     * caches the user display name
+     * @param string $ocName the internal Nextcloud username
+     * @param string $displayName the display name
+     * @param string $displayName2 the second display name
+     */
+    public function cacheUserDisplayName($ocName, $displayName, $displayName2 = '') {
+        $user = $this->userManager->get($ocName);
+        if($user === null) {
+            return;
+        }
+        $displayName = $user->composeAndStoreDisplayName($displayName, $displayName2);
+        $cacheKeyTrunk = 'getDisplayName';
+        $this->connection->writeToCache($cacheKeyTrunk.$ocName, $displayName);
+    }
+
+    /**
+     * creates a unique name for internal Nextcloud use for users. Don't call it directly.
+     * @param string $name the display name of the object
+     * @return string|false with with the name to use in Nextcloud or false if unsuccessful
+     *
+     * Instead of using this method directly, call
+     * createAltInternalOwnCloudName($name, true)
+     */
+    private function _createAltInternalOwnCloudNameForUsers($name) {
+        $attempts = 0;
+        //while loop is just a precaution. If a name is not generated within
+        //20 attempts, something else is very wrong. Avoids infinite loop.
+        while($attempts < 20){
+            $altName = $name . '_' . rand(1000,9999);
+            if(!\OCP\User::userExists($altName)) {
+                return $altName;
+            }
+            $attempts++;
+        }
+        return false;
+    }
+
+    /**
+     * creates a unique name for internal Nextcloud use for groups. Don't call it directly.
+     * @param string $name the display name of the object
+     * @return string|false with with the name to use in Nextcloud or false if unsuccessful.
+     *
+     * Instead of using this method directly, call
+     * createAltInternalOwnCloudName($name, false)
+     *
+     * Group names are also used as display names, so we do a sequential
+     * numbering, e.g. Developers_42 when there are 41 other groups called
+     * "Developers"
+     */
+    private function _createAltInternalOwnCloudNameForGroups($name) {
+        $usedNames = $this->groupMapper->getNamesBySearch($name, "", '_%');
+        if(!($usedNames) || count($usedNames) === 0) {
+            $lastNo = 1; //will become name_2
+        } else {
+            natsort($usedNames);
+            $lastName = array_pop($usedNames);
+            $lastNo = intval(substr($lastName, strrpos($lastName, '_') + 1));
+        }
+        $altName = $name.'_'.strval($lastNo+1);
+        unset($usedNames);
+
+        $attempts = 1;
+        while($attempts < 21){
+            // Check to be really sure it is unique
+            // while loop is just a precaution. If a name is not generated within
+            // 20 attempts, something else is very wrong. Avoids infinite loop.
+            if(!\OC::$server->getGroupManager()->groupExists($altName)) {
+                return $altName;
+            }
+            $altName = $name . '_' . ($lastNo + $attempts);
+            $attempts++;
+        }
+        return false;
+    }
+
+    /**
+     * creates a unique name for internal Nextcloud use.
+     * @param string $name the display name of the object
+     * @param boolean $isUser whether name should be created for a user (true) or a group (false)
+     * @return string|false with with the name to use in Nextcloud or false if unsuccessful
+     */
+    private function createAltInternalOwnCloudName($name, $isUser) {
+        $originalTTL = $this->connection->ldapCacheTTL;
+        $this->connection->setConfiguration(array('ldapCacheTTL' => 0));
+        if($isUser) {
+            $altName = $this->_createAltInternalOwnCloudNameForUsers($name);
+        } else {
+            $altName = $this->_createAltInternalOwnCloudNameForGroups($name);
+        }
+        $this->connection->setConfiguration(array('ldapCacheTTL' => $originalTTL));
+
+        return $altName;
+    }
+
+    /**
+     * fetches a list of users according to a provided loginName and utilizing
+     * the login filter.
+     *
+     * @param string $loginName
+     * @param array $attributes optional, list of attributes to read
+     * @return array
+     */
+    public function fetchUsersByLoginName($loginName, $attributes = array('dn')) {
+        $loginName = $this->escapeFilterPart($loginName);
+        $filter = str_replace('%uid', $loginName, $this->connection->ldapLoginFilter);
+        $users = $this->fetchListOfUsers($filter, $attributes);
+        return $users;
+    }
+
+    /**
+     * counts the number of users according to a provided loginName and
+     * utilizing the login filter.
+     *
+     * @param string $loginName
+     * @return array
+     */
+    public function countUsersByLoginName($loginName) {
+        $loginName = $this->escapeFilterPart($loginName);
+        $filter = str_replace('%uid', $loginName, $this->connection->ldapLoginFilter);
+        $users = $this->countUsers($filter);
+        return $users;
+    }
+
+    /**
+     * @param string $filter
+     * @param string|string[] $attr
+     * @param int $limit
+     * @param int $offset
+     * @return array
+     */
+    public function fetchListOfUsers($filter, $attr, $limit = null, $offset = null) {
+        $ldapRecords = $this->searchUsers($filter, $attr, $limit, $offset);
+        $this->batchApplyUserAttributes($ldapRecords);
+        return $this->fetchList($ldapRecords, (count($attr) > 1));
+    }
+
+    /**
+     * provided with an array of LDAP user records the method will fetch the
+     * user object and requests it to process the freshly fetched attributes and
+     * and their values
+     * @param array $ldapRecords
+     */
+    public function batchApplyUserAttributes(array $ldapRecords){
+        $displayNameAttribute = strtolower($this->connection->ldapUserDisplayName);
+        foreach($ldapRecords as $userRecord) {
+            if(!isset($userRecord[$displayNameAttribute])) {
+                // displayName is obligatory
+                continue;
+            }
+            $ocName  = $this->dn2ocname($userRecord['dn'][0]);
+            if($ocName === false) {
+                continue;
+            }
+            $this->cacheUserExists($ocName);
+            $user = $this->userManager->get($ocName);
+            if($user instanceof OfflineUser) {
+                $user->unmark();
+                $user = $this->userManager->get($ocName);
+            }
+            if ($user !== null) {
+                $user->processAttributes($userRecord);
+            } else {
+                \OC::$server->getLogger()->debug(
+                    "The ldap user manager returned null for $ocName",
+                    ['app'=>'user_ldap']
+                );
+            }
+        }
+    }
+
+    /**
+     * @param string $filter
+     * @param string|string[] $attr
+     * @param int $limit
+     * @param int $offset
+     * @return array
+     */
+    public function fetchListOfGroups($filter, $attr, $limit = null, $offset = null) {
+        return $this->fetchList($this->searchGroups($filter, $attr, $limit, $offset), (count($attr) > 1));
+    }
+
+    /**
+     * @param array $list
+     * @param bool $manyAttributes
+     * @return array
+     */
+    private function fetchList($list, $manyAttributes) {
+        if(is_array($list)) {
+            if($manyAttributes) {
+                return $list;
+            } else {
+                $list = array_reduce($list, function($carry, $item) {
+                    $attribute = array_keys($item)[0];
+                    $carry[] = $item[$attribute][0];
+                    return $carry;
+                }, array());
+                return array_unique($list, SORT_LOCALE_STRING);
+            }
+        }
+
+        //error cause actually, maybe throw an exception in future.
+        return array();
+    }
+
+    /**
+     * executes an LDAP search, optimized for Users
+     * @param string $filter the LDAP filter for the search
+     * @param string|string[] $attr optional, when a certain attribute shall be filtered out
+     * @param integer $limit
+     * @param integer $offset
+     * @return array with the search result
+     *
+     * Executes an LDAP search
+     */
+    public function searchUsers($filter, $attr = null, $limit = null, $offset = null) {
+        return $this->search($filter, $this->connection->ldapBaseUsers, $attr, $limit, $offset);
+    }
+
+    /**
+     * @param string $filter
+     * @param string|string[] $attr
+     * @param int $limit
+     * @param int $offset
+     * @return false|int
+     */
+    public function countUsers($filter, $attr = array('dn'), $limit = null, $offset = null) {
+        return $this->count($filter, $this->connection->ldapBaseUsers, $attr, $limit, $offset);
+    }
+
+    /**
+     * executes an LDAP search, optimized for Groups
+     * @param string $filter the LDAP filter for the search
+     * @param string|string[] $attr optional, when a certain attribute shall be filtered out
+     * @param integer $limit
+     * @param integer $offset
+     * @return array with the search result
+     *
+     * Executes an LDAP search
+     */
+    public function searchGroups($filter, $attr = null, $limit = null, $offset = null) {
+        return $this->search($filter, $this->connection->ldapBaseGroups, $attr, $limit, $offset);
+    }
+
+    /**
+     * returns the number of available groups
+     * @param string $filter the LDAP search filter
+     * @param string[] $attr optional
+     * @param int|null $limit
+     * @param int|null $offset
+     * @return int|bool
+     */
+    public function countGroups($filter, $attr = array('dn'), $limit = null, $offset = null) {
+        return $this->count($filter, $this->connection->ldapBaseGroups, $attr, $limit, $offset);
+    }
+
+    /**
+     * returns the number of available objects on the base DN
+     *
+     * @param int|null $limit
+     * @param int|null $offset
+     * @return int|bool
+     */
+    public function countObjects($limit = null, $offset = null) {
+        return $this->count('objectclass=*', $this->connection->ldapBase, array('dn'), $limit, $offset);
+    }
+
+    /**
+     * Returns the LDAP handler
+     * @throws \OC\ServerNotAvailableException
+     */
+
+    /**
+     * @return mixed
+     * @throws \OC\ServerNotAvailableException
+     */
+    private function invokeLDAPMethod() {
+        $arguments = func_get_args();
+        $command = array_shift($arguments);
+        $cr = array_shift($arguments);
+        if (!method_exists($this->ldap, $command)) {
+            return null;
+        }
+        array_unshift($arguments, $cr);
+        // php no longer supports call-time pass-by-reference
+        // thus cannot support controlPagedResultResponse as the third argument
+        // is a reference
+        $doMethod = function () use ($command, &$arguments) {
+            if ($command == 'controlPagedResultResponse') {
+                throw new \InvalidArgumentException('Invoker does not support controlPagedResultResponse, call LDAP Wrapper directly instead.');
+            } else {
+                return call_user_func_array(array($this->ldap, $command), $arguments);
+            }
+        };
+        try {
+            $ret = $doMethod();
+        } catch (ServerNotAvailableException $e) {
+            /* Server connection lost, attempt to reestablish it
 			 * Maybe implement exponential backoff?
 			 * This was enough to get solr indexer working which has large delays between LDAP fetches.
 			 */
-			\OCP\Util::writeLog('user_ldap', "Connection lost on $command, attempting to reestablish.", \OCP\Util::DEBUG);
-			$this->connection->resetConnectionResource();
-			$cr = $this->connection->getConnectionResource();
-
-			if(!$this->ldap->isResource($cr)) {
-				// Seems like we didn't find any resource.
-				\OCP\Util::writeLog('user_ldap', "Could not $command, because resource is missing.", \OCP\Util::DEBUG);
-				throw $e;
-			}
-
-			$arguments[0] = array_pad([], count($arguments[0]), $cr);
-			$ret = $doMethod();
-		}
-		return $ret;
-	}
-
-	/**
-	 * retrieved. Results will according to the order in the array.
-	 * @param int $limit optional, maximum results to be counted
-	 * @param int $offset optional, a starting point
-	 * @return array|false array with the search result as first value and pagedSearchOK as
-	 * second | false if not successful
-	 * @throws \OC\ServerNotAvailableException
-	 */
-	private function executeSearch($filter, $base, &$attr = null, $limit = null, $offset = null) {
-		if(!is_null($attr) && !is_array($attr)) {
-			$attr = array(mb_strtolower($attr, 'UTF-8'));
-		}
-
-		// See if we have a resource, in case not cancel with message
-		$cr = $this->connection->getConnectionResource();
-		if(!$this->ldap->isResource($cr)) {
-			// Seems like we didn't find any resource.
-			// Return an empty array just like before.
-			\OCP\Util::writeLog('user_ldap', 'Could not search, because resource is missing.', \OCP\Util::DEBUG);
-			return false;
-		}
-
-		//check whether paged search should be attempted
-		$pagedSearchOK = $this->initPagedSearch($filter, $base, $attr, intval($limit), $offset);
-
-		$linkResources = array_pad(array(), count($base), $cr);
-		$sr = $this->invokeLDAPMethod('search', $linkResources, $base, $filter, $attr);
-		// cannot use $cr anymore, might have changed in the previous call!
-		$error = $this->ldap->errno($this->connection->getConnectionResource());
-		if(!is_array($sr) || $error !== 0) {
-			\OCP\Util::writeLog('user_ldap', 'Attempt for Paging?  '.print_r($pagedSearchOK, true), \OCP\Util::ERROR);
-			return false;
-		}
-
-		return array($sr, $pagedSearchOK);
-	}
-
-	/**
-	 * processes an LDAP paged search operation
-	 * @param array $sr the array containing the LDAP search resources
-	 * @param string $filter the LDAP filter for the search
-	 * @param array $base an array containing the LDAP subtree(s) that shall be searched
-	 * @param int $iFoundItems number of results in the single search operation
-	 * @param int $limit maximum results to be counted
-	 * @param int $offset a starting point
-	 * @param bool $pagedSearchOK whether a paged search has been executed
-	 * @param bool $skipHandling required for paged search when cookies to
-	 * prior results need to be gained
-	 * @return bool cookie validity, true if we have more pages, false otherwise.
-	 */
-	private function processPagedSearchStatus($sr, $filter, $base, $iFoundItems, $limit, $offset, $pagedSearchOK, $skipHandling) {
-		$cookie = null;
-		if($pagedSearchOK) {
-			$cr = $this->connection->getConnectionResource();
-			foreach($sr as $key => $res) {
-				if($this->ldap->controlPagedResultResponse($cr, $res, $cookie)) {
-					$this->setPagedResultCookie($base[$key], $filter, $limit, $offset, $cookie);
-				}
-			}
-
-			//browsing through prior pages to get the cookie for the new one
-			if($skipHandling) {
-				return false;
-			}
-			// if count is bigger, then the server does not support
-			// paged search. Instead, he did a normal search. We set a
-			// flag here, so the callee knows how to deal with it.
-			if($iFoundItems <= $limit) {
-				$this->pagedSearchedSuccessful = true;
-			}
-		} else {
-			if(!is_null($limit)) {
-				\OCP\Util::writeLog('user_ldap', 'Paged search was not available', \OCP\Util::INFO);
-			}
-		}
-		/* ++ Fixing RHDS searches with pages with zero results ++
+            \OCP\Util::writeLog('user_ldap', "Connection lost on $command, attempting to reestablish.", \OCP\Util::DEBUG);
+            $this->connection->resetConnectionResource();
+            $cr = $this->connection->getConnectionResource();
+
+            if(!$this->ldap->isResource($cr)) {
+                // Seems like we didn't find any resource.
+                \OCP\Util::writeLog('user_ldap', "Could not $command, because resource is missing.", \OCP\Util::DEBUG);
+                throw $e;
+            }
+
+            $arguments[0] = array_pad([], count($arguments[0]), $cr);
+            $ret = $doMethod();
+        }
+        return $ret;
+    }
+
+    /**
+     * retrieved. Results will according to the order in the array.
+     * @param int $limit optional, maximum results to be counted
+     * @param int $offset optional, a starting point
+     * @return array|false array with the search result as first value and pagedSearchOK as
+     * second | false if not successful
+     * @throws \OC\ServerNotAvailableException
+     */
+    private function executeSearch($filter, $base, &$attr = null, $limit = null, $offset = null) {
+        if(!is_null($attr) && !is_array($attr)) {
+            $attr = array(mb_strtolower($attr, 'UTF-8'));
+        }
+
+        // See if we have a resource, in case not cancel with message
+        $cr = $this->connection->getConnectionResource();
+        if(!$this->ldap->isResource($cr)) {
+            // Seems like we didn't find any resource.
+            // Return an empty array just like before.
+            \OCP\Util::writeLog('user_ldap', 'Could not search, because resource is missing.', \OCP\Util::DEBUG);
+            return false;
+        }
+
+        //check whether paged search should be attempted
+        $pagedSearchOK = $this->initPagedSearch($filter, $base, $attr, intval($limit), $offset);
+
+        $linkResources = array_pad(array(), count($base), $cr);
+        $sr = $this->invokeLDAPMethod('search', $linkResources, $base, $filter, $attr);
+        // cannot use $cr anymore, might have changed in the previous call!
+        $error = $this->ldap->errno($this->connection->getConnectionResource());
+        if(!is_array($sr) || $error !== 0) {
+            \OCP\Util::writeLog('user_ldap', 'Attempt for Paging?  '.print_r($pagedSearchOK, true), \OCP\Util::ERROR);
+            return false;
+        }
+
+        return array($sr, $pagedSearchOK);
+    }
+
+    /**
+     * processes an LDAP paged search operation
+     * @param array $sr the array containing the LDAP search resources
+     * @param string $filter the LDAP filter for the search
+     * @param array $base an array containing the LDAP subtree(s) that shall be searched
+     * @param int $iFoundItems number of results in the single search operation
+     * @param int $limit maximum results to be counted
+     * @param int $offset a starting point
+     * @param bool $pagedSearchOK whether a paged search has been executed
+     * @param bool $skipHandling required for paged search when cookies to
+     * prior results need to be gained
+     * @return bool cookie validity, true if we have more pages, false otherwise.
+     */
+    private function processPagedSearchStatus($sr, $filter, $base, $iFoundItems, $limit, $offset, $pagedSearchOK, $skipHandling) {
+        $cookie = null;
+        if($pagedSearchOK) {
+            $cr = $this->connection->getConnectionResource();
+            foreach($sr as $key => $res) {
+                if($this->ldap->controlPagedResultResponse($cr, $res, $cookie)) {
+                    $this->setPagedResultCookie($base[$key], $filter, $limit, $offset, $cookie);
+                }
+            }
+
+            //browsing through prior pages to get the cookie for the new one
+            if($skipHandling) {
+                return false;
+            }
+            // if count is bigger, then the server does not support
+            // paged search. Instead, he did a normal search. We set a
+            // flag here, so the callee knows how to deal with it.
+            if($iFoundItems <= $limit) {
+                $this->pagedSearchedSuccessful = true;
+            }
+        } else {
+            if(!is_null($limit)) {
+                \OCP\Util::writeLog('user_ldap', 'Paged search was not available', \OCP\Util::INFO);
+            }
+        }
+        /* ++ Fixing RHDS searches with pages with zero results ++
 		 * Return cookie status. If we don't have more pages, with RHDS
 		 * cookie is null, with openldap cookie is an empty string and
 		 * to 386ds '0' is a valid cookie. Even if $iFoundItems == 0
 		 */
-		return !empty($cookie) || $cookie === '0';
-	}
-
-	/**
-	 * executes an LDAP search, but counts the results only
-	 * @param string $filter the LDAP filter for the search
-	 * @param array $base an array containing the LDAP subtree(s) that shall be searched
-	 * @param string|string[] $attr optional, array, one or more attributes that shall be
-	 * retrieved. Results will according to the order in the array.
-	 * @param int $limit optional, maximum results to be counted
-	 * @param int $offset optional, a starting point
-	 * @param bool $skipHandling indicates whether the pages search operation is
-	 * completed
-	 * @return int|false Integer or false if the search could not be initialized
-	 *
-	 */
-	private function count($filter, $base, $attr = null, $limit = null, $offset = null, $skipHandling = false) {
-		\OCP\Util::writeLog('user_ldap', 'Count filter:  '.print_r($filter, true), \OCP\Util::DEBUG);
-
-		$limitPerPage = intval($this->connection->ldapPagingSize);
-		if(!is_null($limit) && $limit < $limitPerPage && $limit > 0) {
-			$limitPerPage = $limit;
-		}
-
-		$counter = 0;
-		$count = null;
-		$this->connection->getConnectionResource();
-
-		do {
-			$search = $this->executeSearch($filter, $base, $attr,
-										   $limitPerPage, $offset);
-			if($search === false) {
-				return $counter > 0 ? $counter : false;
-			}
-			list($sr, $pagedSearchOK) = $search;
-
-			/* ++ Fixing RHDS searches with pages with zero results ++
+        return !empty($cookie) || $cookie === '0';
+    }
+
+    /**
+     * executes an LDAP search, but counts the results only
+     * @param string $filter the LDAP filter for the search
+     * @param array $base an array containing the LDAP subtree(s) that shall be searched
+     * @param string|string[] $attr optional, array, one or more attributes that shall be
+     * retrieved. Results will according to the order in the array.
+     * @param int $limit optional, maximum results to be counted
+     * @param int $offset optional, a starting point
+     * @param bool $skipHandling indicates whether the pages search operation is
+     * completed
+     * @return int|false Integer or false if the search could not be initialized
+     *
+     */
+    private function count($filter, $base, $attr = null, $limit = null, $offset = null, $skipHandling = false) {
+        \OCP\Util::writeLog('user_ldap', 'Count filter:  '.print_r($filter, true), \OCP\Util::DEBUG);
+
+        $limitPerPage = intval($this->connection->ldapPagingSize);
+        if(!is_null($limit) && $limit < $limitPerPage && $limit > 0) {
+            $limitPerPage = $limit;
+        }
+
+        $counter = 0;
+        $count = null;
+        $this->connection->getConnectionResource();
+
+        do {
+            $search = $this->executeSearch($filter, $base, $attr,
+                                            $limitPerPage, $offset);
+            if($search === false) {
+                return $counter > 0 ? $counter : false;
+            }
+            list($sr, $pagedSearchOK) = $search;
+
+            /* ++ Fixing RHDS searches with pages with zero results ++
 			 * countEntriesInSearchResults() method signature changed
 			 * by removing $limit and &$hasHitLimit parameters
 			 */
-			$count = $this->countEntriesInSearchResults($sr);
-			$counter += $count;
+            $count = $this->countEntriesInSearchResults($sr);
+            $counter += $count;
 
-			$hasMorePages = $this->processPagedSearchStatus($sr, $filter, $base, $count, $limitPerPage,
-										$offset, $pagedSearchOK, $skipHandling);
-			$offset += $limitPerPage;
-			/* ++ Fixing RHDS searches with pages with zero results ++
+            $hasMorePages = $this->processPagedSearchStatus($sr, $filter, $base, $count, $limitPerPage,
+                                        $offset, $pagedSearchOK, $skipHandling);
+            $offset += $limitPerPage;
+            /* ++ Fixing RHDS searches with pages with zero results ++
 			 * Continue now depends on $hasMorePages value
 			 */
-			$continue = $pagedSearchOK && $hasMorePages;
-		} while($continue && (is_null($limit) || $limit <= 0 || $limit > $counter));
-
-		return $counter;
-	}
-
-	/**
-	 * @param array $searchResults
-	 * @return int
-	 */
-	private function countEntriesInSearchResults($searchResults) {
-		$counter = 0;
-
-		foreach($searchResults as $res) {
-			$count = intval($this->invokeLDAPMethod('countEntries', $this->connection->getConnectionResource(), $res));
-			$counter += $count;
-		}
-
-		return $counter;
-	}
-
-	/**
-	 * Executes an LDAP search
-	 * @param string $filter the LDAP filter for the search
-	 * @param array $base an array containing the LDAP subtree(s) that shall be searched
-	 * @param string|string[] $attr optional, array, one or more attributes that shall be
-	 * @param int $limit
-	 * @param int $offset
-	 * @param bool $skipHandling
-	 * @return array with the search result
-	 */
-	public function search($filter, $base, $attr = null, $limit = null, $offset = null, $skipHandling = false) {
-		$limitPerPage = intval($this->connection->ldapPagingSize);
-		if(!is_null($limit) && $limit < $limitPerPage && $limit > 0) {
-			$limitPerPage = $limit;
-		}
-
-		/* ++ Fixing RHDS searches with pages with zero results ++
+            $continue = $pagedSearchOK && $hasMorePages;
+        } while($continue && (is_null($limit) || $limit <= 0 || $limit > $counter));
+
+        return $counter;
+    }
+
+    /**
+     * @param array $searchResults
+     * @return int
+     */
+    private function countEntriesInSearchResults($searchResults) {
+        $counter = 0;
+
+        foreach($searchResults as $res) {
+            $count = intval($this->invokeLDAPMethod('countEntries', $this->connection->getConnectionResource(), $res));
+            $counter += $count;
+        }
+
+        return $counter;
+    }
+
+    /**
+     * Executes an LDAP search
+     * @param string $filter the LDAP filter for the search
+     * @param array $base an array containing the LDAP subtree(s) that shall be searched
+     * @param string|string[] $attr optional, array, one or more attributes that shall be
+     * @param int $limit
+     * @param int $offset
+     * @param bool $skipHandling
+     * @return array with the search result
+     */
+    public function search($filter, $base, $attr = null, $limit = null, $offset = null, $skipHandling = false) {
+        $limitPerPage = intval($this->connection->ldapPagingSize);
+        if(!is_null($limit) && $limit < $limitPerPage && $limit > 0) {
+            $limitPerPage = $limit;
+        }
+
+        /* ++ Fixing RHDS searches with pages with zero results ++
 		 * As we can have pages with zero results and/or pages with less
 		 * than $limit results but with a still valid server 'cookie',
 		 * loops through until we get $continue equals true and
 		 * $findings['count'] < $limit
 		 */
-		$findings = array();
-		$savedoffset = $offset;
-		do {
-			$search = $this->executeSearch($filter, $base, $attr, $limitPerPage, $offset);
-			if($search === false) {
-				return array();
-			}
-			list($sr, $pagedSearchOK) = $search;
-			$cr = $this->connection->getConnectionResource();
-
-			if($skipHandling) {
-				//i.e. result do not need to be fetched, we just need the cookie
-				//thus pass 1 or any other value as $iFoundItems because it is not
-				//used
-				$this->processPagedSearchStatus($sr, $filter, $base, 1, $limitPerPage,
-								$offset, $pagedSearchOK,
-								$skipHandling);
-				return array();
-			}
-
-			$iFoundItems = 0;
-			foreach($sr as $res) {
-				$findings = array_merge($findings, $this->invokeLDAPMethod('getEntries', $cr, $res));
-				$iFoundItems = max($iFoundItems, $findings['count']);
-				unset($findings['count']);
-			}
-
-			$continue = $this->processPagedSearchStatus($sr, $filter, $base, $iFoundItems,
-				$limitPerPage, $offset, $pagedSearchOK,
-										$skipHandling);
-			$offset += $limitPerPage;
-		} while ($continue && $pagedSearchOK && ($limit === null || count($findings) < $limit));
-		// reseting offset
-		$offset = $savedoffset;
-
-		// if we're here, probably no connection resource is returned.
-		// to make Nextcloud behave nicely, we simply give back an empty array.
-		if(is_null($findings)) {
-			return array();
-		}
-
-		if(!is_null($attr)) {
-			$selection = array();
-			$i = 0;
-			foreach($findings as $item) {
-				if(!is_array($item)) {
-					continue;
-				}
-				$item = \OCP\Util::mb_array_change_key_case($item, MB_CASE_LOWER, 'UTF-8');
-				foreach($attr as $key) {
-					$key = mb_strtolower($key, 'UTF-8');
-					if(isset($item[$key])) {
-						if(is_array($item[$key]) && isset($item[$key]['count'])) {
-							unset($item[$key]['count']);
-						}
-						if($key !== 'dn') {
-							$selection[$i][$key] = $this->resemblesDN($key) ?
-								$this->helper->sanitizeDN($item[$key])
-								: $item[$key];
-						} else {
-							$selection[$i][$key] = [$this->helper->sanitizeDN($item[$key])];
-						}
-					}
-
-				}
-				$i++;
-			}
-			$findings = $selection;
-		}
-		//we slice the findings, when
-		//a) paged search unsuccessful, though attempted
-		//b) no paged search, but limit set
-		if((!$this->getPagedSearchResultState()
-			&& $pagedSearchOK)
-			|| (
-				!$pagedSearchOK
-				&& !is_null($limit)
-			)
-		) {
-			$findings = array_slice($findings, intval($offset), $limit);
-		}
-		return $findings;
-	}
-
-	/**
-	 * @param string $name
-	 * @return bool|mixed|string
-	 */
-	public function sanitizeUsername($name) {
-		if($this->connection->ldapIgnoreNamingRules) {
-			return $name;
-		}
-
-		// Transliteration
-		// latin characters to ASCII
-		$name = iconv('UTF-8', 'ASCII//TRANSLIT', $name);
-
-		// Replacements
-		$name = str_replace(' ', '_', $name);
-
-		// Every remaining disallowed characters will be removed
-		$name = preg_replace('/[^a-zA-Z0-9_.@-]/u', '', $name);
-
-		return $name;
-	}
-
-	/**
-	* escapes (user provided) parts for LDAP filter
-	* @param string $input, the provided value
-	* @param bool $allowAsterisk whether in * at the beginning should be preserved
-	* @return string the escaped string
-	*/
-	public function escapeFilterPart($input, $allowAsterisk = false) {
-		$asterisk = '';
-		if($allowAsterisk && strlen($input) > 0 && $input[0] === '*') {
-			$asterisk = '*';
-			$input = mb_substr($input, 1, null, 'UTF-8');
-		}
-		$search  = array('*', '\\', '(', ')');
-		$replace = array('\\*', '\\\\', '\\(', '\\)');
-		return $asterisk . str_replace($search, $replace, $input);
-	}
-
-	/**
-	 * combines the input filters with AND
-	 * @param string[] $filters the filters to connect
-	 * @return string the combined filter
-	 */
-	public function combineFilterWithAnd($filters) {
-		return $this->combineFilter($filters, '&');
-	}
-
-	/**
-	 * combines the input filters with OR
-	 * @param string[] $filters the filters to connect
-	 * @return string the combined filter
-	 * Combines Filter arguments with OR
-	 */
-	public function combineFilterWithOr($filters) {
-		return $this->combineFilter($filters, '|');
-	}
-
-	/**
-	 * combines the input filters with given operator
-	 * @param string[] $filters the filters to connect
-	 * @param string $operator either & or |
-	 * @return string the combined filter
-	 */
-	private function combineFilter($filters, $operator) {
-		$combinedFilter = '('.$operator;
-		foreach($filters as $filter) {
-			if ($filter !== '' && $filter[0] !== '(') {
-				$filter = '('.$filter.')';
-			}
-			$combinedFilter.=$filter;
-		}
-		$combinedFilter.=')';
-		return $combinedFilter;
-	}
-
-	/**
-	 * creates a filter part for to perform search for users
-	 * @param string $search the search term
-	 * @return string the final filter part to use in LDAP searches
-	 */
-	public function getFilterPartForUserSearch($search) {
-		return $this->getFilterPartForSearch($search,
-			$this->connection->ldapAttributesForUserSearch,
-			$this->connection->ldapUserDisplayName);
-	}
-
-	/**
-	 * creates a filter part for to perform search for groups
-	 * @param string $search the search term
-	 * @return string the final filter part to use in LDAP searches
-	 */
-	public function getFilterPartForGroupSearch($search) {
-		return $this->getFilterPartForSearch($search,
-			$this->connection->ldapAttributesForGroupSearch,
-			$this->connection->ldapGroupDisplayName);
-	}
-
-	/**
-	 * creates a filter part for searches by splitting up the given search
-	 * string into single words
-	 * @param string $search the search term
-	 * @param string[] $searchAttributes needs to have at least two attributes,
-	 * otherwise it does not make sense :)
-	 * @return string the final filter part to use in LDAP searches
-	 * @throws \Exception
-	 */
-	private function getAdvancedFilterPartForSearch($search, $searchAttributes) {
-		if(!is_array($searchAttributes) || count($searchAttributes) < 2) {
-			throw new \Exception('searchAttributes must be an array with at least two string');
-		}
-		$searchWords = explode(' ', trim($search));
-		$wordFilters = array();
-		foreach($searchWords as $word) {
-			$word = $this->prepareSearchTerm($word);
-			//every word needs to appear at least once
-			$wordMatchOneAttrFilters = array();
-			foreach($searchAttributes as $attr) {
-				$wordMatchOneAttrFilters[] = $attr . '=' . $word;
-			}
-			$wordFilters[] = $this->combineFilterWithOr($wordMatchOneAttrFilters);
-		}
-		return $this->combineFilterWithAnd($wordFilters);
-	}
-
-	/**
-	 * creates a filter part for searches
-	 * @param string $search the search term
-	 * @param string[]|null $searchAttributes
-	 * @param string $fallbackAttribute a fallback attribute in case the user
-	 * did not define search attributes. Typically the display name attribute.
-	 * @return string the final filter part to use in LDAP searches
-	 */
-	private function getFilterPartForSearch($search, $searchAttributes, $fallbackAttribute) {
-		$filter = array();
-		$haveMultiSearchAttributes = (is_array($searchAttributes) && count($searchAttributes) > 0);
-		if($haveMultiSearchAttributes && strpos(trim($search), ' ') !== false) {
-			try {
-				return $this->getAdvancedFilterPartForSearch($search, $searchAttributes);
-			} catch(\Exception $e) {
-				\OCP\Util::writeLog(
-					'user_ldap',
-					'Creating advanced filter for search failed, falling back to simple method.',
-					\OCP\Util::INFO
-				);
-			}
-		}
-
-		$search = $this->prepareSearchTerm($search);
-		if(!is_array($searchAttributes) || count($searchAttributes) === 0) {
-			if ($fallbackAttribute === '') {
-				return '';
-			}
-			$filter[] = $fallbackAttribute . '=' . $search;
-		} else {
-			foreach($searchAttributes as $attribute) {
-				$filter[] = $attribute . '=' . $search;
-			}
-		}
-		if(count($filter) === 1) {
-			return '('.$filter[0].')';
-		}
-		return $this->combineFilterWithOr($filter);
-	}
-
-	/**
-	 * returns the search term depending on whether we are allowed
-	 * list users found by ldap with the current input appended by
-	 * a *
-	 * @return string
-	 */
-	private function prepareSearchTerm($term) {
-		$config = \OC::$server->getConfig();
-
-		$allowEnum = $config->getAppValue('core', 'shareapi_allow_share_dialog_user_enumeration', 'yes');
-
-		$result = $term;
-		if ($term === '') {
-			$result = '*';
-		} else if ($allowEnum !== 'no') {
-			$result = $term . '*';
-		}
-		return $result;
-	}
-
-	/**
-	 * returns the filter used for counting users
-	 * @return string
-	 */
-	public function getFilterForUserCount() {
-		$filter = $this->combineFilterWithAnd(array(
-			$this->connection->ldapUserFilter,
-			$this->connection->ldapUserDisplayName . '=*'
-		));
-
-		return $filter;
-	}
-
-	/**
-	 * @param string $name
-	 * @param string $password
-	 * @return bool
-	 */
-	public function areCredentialsValid($name, $password) {
-		$name = $this->helper->DNasBaseParameter($name);
-		$testConnection = clone $this->connection;
-		$credentials = array(
-			'ldapAgentName' => $name,
-			'ldapAgentPassword' => $password
-		);
-		if(!$testConnection->setConfiguration($credentials)) {
-			return false;
-		}
-		return $testConnection->bind();
-	}
-
-	/**
-	 * reverse lookup of a DN given a known UUID
-	 *
-	 * @param string $uuid
-	 * @return string
-	 * @throws \Exception
-	 */
-	public function getUserDnByUuid($uuid) {
-		$uuidOverride = $this->connection->ldapExpertUUIDUserAttr;
-		$filter       = $this->connection->ldapUserFilter;
-		$base         = $this->connection->ldapBaseUsers;
-
-		if ($this->connection->ldapUuidUserAttribute === 'auto' && $uuidOverride === '') {
-			// Sacrebleu! The UUID attribute is unknown :( We need first an
-			// existing DN to be able to reliably detect it.
-			$result = $this->search($filter, $base, ['dn'], 1);
-			if(!isset($result[0]) || !isset($result[0]['dn'])) {
-				throw new \Exception('Cannot determine UUID attribute');
-			}
-			$dn = $result[0]['dn'][0];
-			if(!$this->detectUuidAttribute($dn, true)) {
-				throw new \Exception('Cannot determine UUID attribute');
-			}
-		} else {
-			// The UUID attribute is either known or an override is given.
-			// By calling this method we ensure that $this->connection->$uuidAttr
-			// is definitely set
-			if(!$this->detectUuidAttribute('', true)) {
-				throw new \Exception('Cannot determine UUID attribute');
-			}
-		}
-
-		$uuidAttr = $this->connection->ldapUuidUserAttribute;
-		if($uuidAttr === 'guid' || $uuidAttr === 'objectguid') {
-			$uuid = $this->formatGuid2ForFilterUser($uuid);
-		}
-
-		$filter = $uuidAttr . '=' . $uuid;
-		$result = $this->searchUsers($filter, ['dn'], 2);
-		if(is_array($result) && isset($result[0]) && isset($result[0]['dn']) && count($result) === 1) {
-			// we put the count into account to make sure that this is
-			// really unique
-			return $result[0]['dn'][0];
-		}
-
-		throw new \Exception('Cannot determine UUID attribute');
-	}
-
-	/**
-	 * auto-detects the directory's UUID attribute
-	 * @param string $dn a known DN used to check against
-	 * @param bool $isUser
-	 * @param bool $force the detection should be run, even if it is not set to auto
-	 * @return bool true on success, false otherwise
-	 */
-	private function detectUuidAttribute($dn, $isUser = true, $force = false) {
-		if($isUser) {
-			$uuidAttr     = 'ldapUuidUserAttribute';
-			$uuidOverride = $this->connection->ldapExpertUUIDUserAttr;
-		} else {
-			$uuidAttr     = 'ldapUuidGroupAttribute';
-			$uuidOverride = $this->connection->ldapExpertUUIDGroupAttr;
-		}
-
-		if(($this->connection->$uuidAttr !== 'auto') && !$force) {
-			return true;
-		}
-
-		if (is_string($uuidOverride) && trim($uuidOverride) !== '' && !$force) {
-			$this->connection->$uuidAttr = $uuidOverride;
-			return true;
-		}
-
-		// for now, supported attributes are entryUUID, nsuniqueid, objectGUID, ipaUniqueID
-		$testAttributes = array('entryuuid', 'nsuniqueid', 'objectguid', 'guid', 'ipauniqueid');
-
-		foreach($testAttributes as $attribute) {
-			$value = $this->readAttribute($dn, $attribute);
-			if(is_array($value) && isset($value[0]) && !empty($value[0])) {
-				\OCP\Util::writeLog('user_ldap',
-									'Setting '.$attribute.' as '.$uuidAttr,
-									\OCP\Util::DEBUG);
-				$this->connection->$uuidAttr = $attribute;
-				return true;
-			}
-		}
-		\OCP\Util::writeLog('user_ldap',
-							'Could not autodetect the UUID attribute',
-							\OCP\Util::ERROR);
-
-		return false;
-	}
-
-	/**
-	 * @param string $dn
-	 * @param bool $isUser
-	 * @return string|bool
-	 */
-	public function getUUID($dn, $isUser = true) {
-		if($isUser) {
-			$uuidAttr     = 'ldapUuidUserAttribute';
-			$uuidOverride = $this->connection->ldapExpertUUIDUserAttr;
-		} else {
-			$uuidAttr     = 'ldapUuidGroupAttribute';
-			$uuidOverride = $this->connection->ldapExpertUUIDGroupAttr;
-		}
-
-		$uuid = false;
-		if($this->detectUuidAttribute($dn, $isUser)) {
-			$uuid = $this->readAttribute($dn, $this->connection->$uuidAttr);
-			if( !is_array($uuid)
-				&& $uuidOverride !== ''
-				&& $this->detectUuidAttribute($dn, $isUser, true)) {
-					$uuid = $this->readAttribute($dn,
-												 $this->connection->$uuidAttr);
-			}
-			if(is_array($uuid) && isset($uuid[0]) && !empty($uuid[0])) {
-				$uuid = $uuid[0];
-			}
-		}
-
-		return $uuid;
-	}
-
-	/**
-	 * converts a binary ObjectGUID into a string representation
-	 * @param string $oguid the ObjectGUID in it's binary form as retrieved from AD
-	 * @return string
-	 * @link http://www.php.net/manual/en/function.ldap-get-values-len.php#73198
-	 */
-	private function convertObjectGUID2Str($oguid) {
-		$hex_guid = bin2hex($oguid);
-		$hex_guid_to_guid_str = '';
-		for($k = 1; $k <= 4; ++$k) {
-			$hex_guid_to_guid_str .= substr($hex_guid, 8 - 2 * $k, 2);
-		}
-		$hex_guid_to_guid_str .= '-';
-		for($k = 1; $k <= 2; ++$k) {
-			$hex_guid_to_guid_str .= substr($hex_guid, 12 - 2 * $k, 2);
-		}
-		$hex_guid_to_guid_str .= '-';
-		for($k = 1; $k <= 2; ++$k) {
-			$hex_guid_to_guid_str .= substr($hex_guid, 16 - 2 * $k, 2);
-		}
-		$hex_guid_to_guid_str .= '-' . substr($hex_guid, 16, 4);
-		$hex_guid_to_guid_str .= '-' . substr($hex_guid, 20);
-
-		return strtoupper($hex_guid_to_guid_str);
-	}
-
-	/**
-	 * the first three blocks of the string-converted GUID happen to be in
-	 * reverse order. In order to use it in a filter, this needs to be
-	 * corrected. Furthermore the dashes need to be replaced and \\ preprended
-	 * to every two hax figures.
-	 *
-	 * If an invalid string is passed, it will be returned without change.
-	 *
-	 * @param string $guid
-	 * @return string
-	 */
-	public function formatGuid2ForFilterUser($guid) {
-		if(!is_string($guid)) {
-			throw new \InvalidArgumentException('String expected');
-		}
-		$blocks = explode('-', $guid);
-		if(count($blocks) !== 5) {
-			/*
+        $findings = array();
+        $savedoffset = $offset;
+        do {
+            $search = $this->executeSearch($filter, $base, $attr, $limitPerPage, $offset);
+            if($search === false) {
+                return array();
+            }
+            list($sr, $pagedSearchOK) = $search;
+            $cr = $this->connection->getConnectionResource();
+
+            if($skipHandling) {
+                //i.e. result do not need to be fetched, we just need the cookie
+                //thus pass 1 or any other value as $iFoundItems because it is not
+                //used
+                $this->processPagedSearchStatus($sr, $filter, $base, 1, $limitPerPage,
+                                $offset, $pagedSearchOK,
+                                $skipHandling);
+                return array();
+            }
+
+            $iFoundItems = 0;
+            foreach($sr as $res) {
+                $findings = array_merge($findings, $this->invokeLDAPMethod('getEntries', $cr, $res));
+                $iFoundItems = max($iFoundItems, $findings['count']);
+                unset($findings['count']);
+            }
+
+            $continue = $this->processPagedSearchStatus($sr, $filter, $base, $iFoundItems,
+                $limitPerPage, $offset, $pagedSearchOK,
+                                        $skipHandling);
+            $offset += $limitPerPage;
+        } while ($continue && $pagedSearchOK && ($limit === null || count($findings) < $limit));
+        // reseting offset
+        $offset = $savedoffset;
+
+        // if we're here, probably no connection resource is returned.
+        // to make Nextcloud behave nicely, we simply give back an empty array.
+        if(is_null($findings)) {
+            return array();
+        }
+
+        if(!is_null($attr)) {
+            $selection = array();
+            $i = 0;
+            foreach($findings as $item) {
+                if(!is_array($item)) {
+                    continue;
+                }
+                $item = \OCP\Util::mb_array_change_key_case($item, MB_CASE_LOWER, 'UTF-8');
+                foreach($attr as $key) {
+                    $key = mb_strtolower($key, 'UTF-8');
+                    if(isset($item[$key])) {
+                        if(is_array($item[$key]) && isset($item[$key]['count'])) {
+                            unset($item[$key]['count']);
+                        }
+                        if($key !== 'dn') {
+                            $selection[$i][$key] = $this->resemblesDN($key) ?
+                                $this->helper->sanitizeDN($item[$key])
+                                : $item[$key];
+                        } else {
+                            $selection[$i][$key] = [$this->helper->sanitizeDN($item[$key])];
+                        }
+                    }
+
+                }
+                $i++;
+            }
+            $findings = $selection;
+        }
+        //we slice the findings, when
+        //a) paged search unsuccessful, though attempted
+        //b) no paged search, but limit set
+        if((!$this->getPagedSearchResultState()
+            && $pagedSearchOK)
+            || (
+                !$pagedSearchOK
+                && !is_null($limit)
+            )
+        ) {
+            $findings = array_slice($findings, intval($offset), $limit);
+        }
+        return $findings;
+    }
+
+    /**
+     * @param string $name
+     * @return bool|mixed|string
+     */
+    public function sanitizeUsername($name) {
+        if($this->connection->ldapIgnoreNamingRules) {
+            return $name;
+        }
+
+        // Transliteration
+        // latin characters to ASCII
+        $name = iconv('UTF-8', 'ASCII//TRANSLIT', $name);
+
+        // Replacements
+        $name = str_replace(' ', '_', $name);
+
+        // Every remaining disallowed characters will be removed
+        $name = preg_replace('/[^a-zA-Z0-9_.@-]/u', '', $name);
+
+        return $name;
+    }
+
+    /**
+     * escapes (user provided) parts for LDAP filter
+     * @param string $input, the provided value
+     * @param bool $allowAsterisk whether in * at the beginning should be preserved
+     * @return string the escaped string
+     */
+    public function escapeFilterPart($input, $allowAsterisk = false) {
+        $asterisk = '';
+        if($allowAsterisk && strlen($input) > 0 && $input[0] === '*') {
+            $asterisk = '*';
+            $input = mb_substr($input, 1, null, 'UTF-8');
+        }
+        $search  = array('*', '\\', '(', ')');
+        $replace = array('\\*', '\\\\', '\\(', '\\)');
+        return $asterisk . str_replace($search, $replace, $input);
+    }
+
+    /**
+     * combines the input filters with AND
+     * @param string[] $filters the filters to connect
+     * @return string the combined filter
+     */
+    public function combineFilterWithAnd($filters) {
+        return $this->combineFilter($filters, '&');
+    }
+
+    /**
+     * combines the input filters with OR
+     * @param string[] $filters the filters to connect
+     * @return string the combined filter
+     * Combines Filter arguments with OR
+     */
+    public function combineFilterWithOr($filters) {
+        return $this->combineFilter($filters, '|');
+    }
+
+    /**
+     * combines the input filters with given operator
+     * @param string[] $filters the filters to connect
+     * @param string $operator either & or |
+     * @return string the combined filter
+     */
+    private function combineFilter($filters, $operator) {
+        $combinedFilter = '('.$operator;
+        foreach($filters as $filter) {
+            if ($filter !== '' && $filter[0] !== '(') {
+                $filter = '('.$filter.')';
+            }
+            $combinedFilter.=$filter;
+        }
+        $combinedFilter.=')';
+        return $combinedFilter;
+    }
+
+    /**
+     * creates a filter part for to perform search for users
+     * @param string $search the search term
+     * @return string the final filter part to use in LDAP searches
+     */
+    public function getFilterPartForUserSearch($search) {
+        return $this->getFilterPartForSearch($search,
+            $this->connection->ldapAttributesForUserSearch,
+            $this->connection->ldapUserDisplayName);
+    }
+
+    /**
+     * creates a filter part for to perform search for groups
+     * @param string $search the search term
+     * @return string the final filter part to use in LDAP searches
+     */
+    public function getFilterPartForGroupSearch($search) {
+        return $this->getFilterPartForSearch($search,
+            $this->connection->ldapAttributesForGroupSearch,
+            $this->connection->ldapGroupDisplayName);
+    }
+
+    /**
+     * creates a filter part for searches by splitting up the given search
+     * string into single words
+     * @param string $search the search term
+     * @param string[] $searchAttributes needs to have at least two attributes,
+     * otherwise it does not make sense :)
+     * @return string the final filter part to use in LDAP searches
+     * @throws \Exception
+     */
+    private function getAdvancedFilterPartForSearch($search, $searchAttributes) {
+        if(!is_array($searchAttributes) || count($searchAttributes) < 2) {
+            throw new \Exception('searchAttributes must be an array with at least two string');
+        }
+        $searchWords = explode(' ', trim($search));
+        $wordFilters = array();
+        foreach($searchWords as $word) {
+            $word = $this->prepareSearchTerm($word);
+            //every word needs to appear at least once
+            $wordMatchOneAttrFilters = array();
+            foreach($searchAttributes as $attr) {
+                $wordMatchOneAttrFilters[] = $attr . '=' . $word;
+            }
+            $wordFilters[] = $this->combineFilterWithOr($wordMatchOneAttrFilters);
+        }
+        return $this->combineFilterWithAnd($wordFilters);
+    }
+
+    /**
+     * creates a filter part for searches
+     * @param string $search the search term
+     * @param string[]|null $searchAttributes
+     * @param string $fallbackAttribute a fallback attribute in case the user
+     * did not define search attributes. Typically the display name attribute.
+     * @return string the final filter part to use in LDAP searches
+     */
+    private function getFilterPartForSearch($search, $searchAttributes, $fallbackAttribute) {
+        $filter = array();
+        $haveMultiSearchAttributes = (is_array($searchAttributes) && count($searchAttributes) > 0);
+        if($haveMultiSearchAttributes && strpos(trim($search), ' ') !== false) {
+            try {
+                return $this->getAdvancedFilterPartForSearch($search, $searchAttributes);
+            } catch(\Exception $e) {
+                \OCP\Util::writeLog(
+                    'user_ldap',
+                    'Creating advanced filter for search failed, falling back to simple method.',
+                    \OCP\Util::INFO
+                );
+            }
+        }
+
+        $search = $this->prepareSearchTerm($search);
+        if(!is_array($searchAttributes) || count($searchAttributes) === 0) {
+            if ($fallbackAttribute === '') {
+                return '';
+            }
+            $filter[] = $fallbackAttribute . '=' . $search;
+        } else {
+            foreach($searchAttributes as $attribute) {
+                $filter[] = $attribute . '=' . $search;
+            }
+        }
+        if(count($filter) === 1) {
+            return '('.$filter[0].')';
+        }
+        return $this->combineFilterWithOr($filter);
+    }
+
+    /**
+     * returns the search term depending on whether we are allowed
+     * list users found by ldap with the current input appended by
+     * a *
+     * @return string
+     */
+    private function prepareSearchTerm($term) {
+        $config = \OC::$server->getConfig();
+
+        $allowEnum = $config->getAppValue('core', 'shareapi_allow_share_dialog_user_enumeration', 'yes');
+
+        $result = $term;
+        if ($term === '') {
+            $result = '*';
+        } else if ($allowEnum !== 'no') {
+            $result = $term . '*';
+        }
+        return $result;
+    }
+
+    /**
+     * returns the filter used for counting users
+     * @return string
+     */
+    public function getFilterForUserCount() {
+        $filter = $this->combineFilterWithAnd(array(
+            $this->connection->ldapUserFilter,
+            $this->connection->ldapUserDisplayName . '=*'
+        ));
+
+        return $filter;
+    }
+
+    /**
+     * @param string $name
+     * @param string $password
+     * @return bool
+     */
+    public function areCredentialsValid($name, $password) {
+        $name = $this->helper->DNasBaseParameter($name);
+        $testConnection = clone $this->connection;
+        $credentials = array(
+            'ldapAgentName' => $name,
+            'ldapAgentPassword' => $password
+        );
+        if(!$testConnection->setConfiguration($credentials)) {
+            return false;
+        }
+        return $testConnection->bind();
+    }
+
+    /**
+     * reverse lookup of a DN given a known UUID
+     *
+     * @param string $uuid
+     * @return string
+     * @throws \Exception
+     */
+    public function getUserDnByUuid($uuid) {
+        $uuidOverride = $this->connection->ldapExpertUUIDUserAttr;
+        $filter       = $this->connection->ldapUserFilter;
+        $base         = $this->connection->ldapBaseUsers;
+
+        if ($this->connection->ldapUuidUserAttribute === 'auto' && $uuidOverride === '') {
+            // Sacrebleu! The UUID attribute is unknown :( We need first an
+            // existing DN to be able to reliably detect it.
+            $result = $this->search($filter, $base, ['dn'], 1);
+            if(!isset($result[0]) || !isset($result[0]['dn'])) {
+                throw new \Exception('Cannot determine UUID attribute');
+            }
+            $dn = $result[0]['dn'][0];
+            if(!$this->detectUuidAttribute($dn, true)) {
+                throw new \Exception('Cannot determine UUID attribute');
+            }
+        } else {
+            // The UUID attribute is either known or an override is given.
+            // By calling this method we ensure that $this->connection->$uuidAttr
+            // is definitely set
+            if(!$this->detectUuidAttribute('', true)) {
+                throw new \Exception('Cannot determine UUID attribute');
+            }
+        }
+
+        $uuidAttr = $this->connection->ldapUuidUserAttribute;
+        if($uuidAttr === 'guid' || $uuidAttr === 'objectguid') {
+            $uuid = $this->formatGuid2ForFilterUser($uuid);
+        }
+
+        $filter = $uuidAttr . '=' . $uuid;
+        $result = $this->searchUsers($filter, ['dn'], 2);
+        if(is_array($result) && isset($result[0]) && isset($result[0]['dn']) && count($result) === 1) {
+            // we put the count into account to make sure that this is
+            // really unique
+            return $result[0]['dn'][0];
+        }
+
+        throw new \Exception('Cannot determine UUID attribute');
+    }
+
+    /**
+     * auto-detects the directory's UUID attribute
+     * @param string $dn a known DN used to check against
+     * @param bool $isUser
+     * @param bool $force the detection should be run, even if it is not set to auto
+     * @return bool true on success, false otherwise
+     */
+    private function detectUuidAttribute($dn, $isUser = true, $force = false) {
+        if($isUser) {
+            $uuidAttr     = 'ldapUuidUserAttribute';
+            $uuidOverride = $this->connection->ldapExpertUUIDUserAttr;
+        } else {
+            $uuidAttr     = 'ldapUuidGroupAttribute';
+            $uuidOverride = $this->connection->ldapExpertUUIDGroupAttr;
+        }
+
+        if(($this->connection->$uuidAttr !== 'auto') && !$force) {
+            return true;
+        }
+
+        if (is_string($uuidOverride) && trim($uuidOverride) !== '' && !$force) {
+            $this->connection->$uuidAttr = $uuidOverride;
+            return true;
+        }
+
+        // for now, supported attributes are entryUUID, nsuniqueid, objectGUID, ipaUniqueID
+        $testAttributes = array('entryuuid', 'nsuniqueid', 'objectguid', 'guid', 'ipauniqueid');
+
+        foreach($testAttributes as $attribute) {
+            $value = $this->readAttribute($dn, $attribute);
+            if(is_array($value) && isset($value[0]) && !empty($value[0])) {
+                \OCP\Util::writeLog('user_ldap',
+                                    'Setting '.$attribute.' as '.$uuidAttr,
+                                    \OCP\Util::DEBUG);
+                $this->connection->$uuidAttr = $attribute;
+                return true;
+            }
+        }
+        \OCP\Util::writeLog('user_ldap',
+                            'Could not autodetect the UUID attribute',
+                            \OCP\Util::ERROR);
+
+        return false;
+    }
+
+    /**
+     * @param string $dn
+     * @param bool $isUser
+     * @return string|bool
+     */
+    public function getUUID($dn, $isUser = true) {
+        if($isUser) {
+            $uuidAttr     = 'ldapUuidUserAttribute';
+            $uuidOverride = $this->connection->ldapExpertUUIDUserAttr;
+        } else {
+            $uuidAttr     = 'ldapUuidGroupAttribute';
+            $uuidOverride = $this->connection->ldapExpertUUIDGroupAttr;
+        }
+
+        $uuid = false;
+        if($this->detectUuidAttribute($dn, $isUser)) {
+            $uuid = $this->readAttribute($dn, $this->connection->$uuidAttr);
+            if( !is_array($uuid)
+                && $uuidOverride !== ''
+                && $this->detectUuidAttribute($dn, $isUser, true)) {
+                    $uuid = $this->readAttribute($dn,
+                                                    $this->connection->$uuidAttr);
+            }
+            if(is_array($uuid) && isset($uuid[0]) && !empty($uuid[0])) {
+                $uuid = $uuid[0];
+            }
+        }
+
+        return $uuid;
+    }
+
+    /**
+     * converts a binary ObjectGUID into a string representation
+     * @param string $oguid the ObjectGUID in it's binary form as retrieved from AD
+     * @return string
+     * @link http://www.php.net/manual/en/function.ldap-get-values-len.php#73198
+     */
+    private function convertObjectGUID2Str($oguid) {
+        $hex_guid = bin2hex($oguid);
+        $hex_guid_to_guid_str = '';
+        for($k = 1; $k <= 4; ++$k) {
+            $hex_guid_to_guid_str .= substr($hex_guid, 8 - 2 * $k, 2);
+        }
+        $hex_guid_to_guid_str .= '-';
+        for($k = 1; $k <= 2; ++$k) {
+            $hex_guid_to_guid_str .= substr($hex_guid, 12 - 2 * $k, 2);
+        }
+        $hex_guid_to_guid_str .= '-';
+        for($k = 1; $k <= 2; ++$k) {
+            $hex_guid_to_guid_str .= substr($hex_guid, 16 - 2 * $k, 2);
+        }
+        $hex_guid_to_guid_str .= '-' . substr($hex_guid, 16, 4);
+        $hex_guid_to_guid_str .= '-' . substr($hex_guid, 20);
+
+        return strtoupper($hex_guid_to_guid_str);
+    }
+
+    /**
+     * the first three blocks of the string-converted GUID happen to be in
+     * reverse order. In order to use it in a filter, this needs to be
+     * corrected. Furthermore the dashes need to be replaced and \\ preprended
+     * to every two hax figures.
+     *
+     * If an invalid string is passed, it will be returned without change.
+     *
+     * @param string $guid
+     * @return string
+     */
+    public function formatGuid2ForFilterUser($guid) {
+        if(!is_string($guid)) {
+            throw new \InvalidArgumentException('String expected');
+        }
+        $blocks = explode('-', $guid);
+        if(count($blocks) !== 5) {
+            /*
 			 * Why not throw an Exception instead? This method is a utility
 			 * called only when trying to figure out whether a "missing" known
 			 * LDAP user was or was not renamed on the LDAP server. And this
@@ -1638,275 +1638,275 @@ 
 			 * an exception here would kill the experience for a valid, acting
 			 * user. Instead we write a log message.
 			 */
-			\OC::$server->getLogger()->info(
-				'Passed string does not resemble a valid GUID. Known UUID ' .
-				'({uuid}) probably does not match UUID configuration.',
-				[ 'app' => 'user_ldap', 'uuid' => $guid ]
-			);
-			return $guid;
-		}
-		for($i=0; $i < 3; $i++) {
-			$pairs = str_split($blocks[$i], 2);
-			$pairs = array_reverse($pairs);
-			$blocks[$i] = implode('', $pairs);
-		}
-		for($i=0; $i < 5; $i++) {
-			$pairs = str_split($blocks[$i], 2);
-			$blocks[$i] = '\\' . implode('\\', $pairs);
-		}
-		return implode('', $blocks);
-	}
-
-	/**
-	 * gets a SID of the domain of the given dn
-	 * @param string $dn
-	 * @return string|bool
-	 */
-	public function getSID($dn) {
-		$domainDN = $this->getDomainDNFromDN($dn);
-		$cacheKey = 'getSID-'.$domainDN;
-		$sid = $this->connection->getFromCache($cacheKey);
-		if(!is_null($sid)) {
-			return $sid;
-		}
-
-		$objectSid = $this->readAttribute($domainDN, 'objectsid');
-		if(!is_array($objectSid) || empty($objectSid)) {
-			$this->connection->writeToCache($cacheKey, false);
-			return false;
-		}
-		$domainObjectSid = $this->convertSID2Str($objectSid[0]);
-		$this->connection->writeToCache($cacheKey, $domainObjectSid);
-
-		return $domainObjectSid;
-	}
-
-	/**
-	 * converts a binary SID into a string representation
-	 * @param string $sid
-	 * @return string
-	 */
-	public function convertSID2Str($sid) {
-		// The format of a SID binary string is as follows:
-		// 1 byte for the revision level
-		// 1 byte for the number n of variable sub-ids
-		// 6 bytes for identifier authority value
-		// n*4 bytes for n sub-ids
-		//
-		// Example: 010400000000000515000000a681e50e4d6c6c2bca32055f
-		//  Legend: RRNNAAAAAAAAAAAA11111111222222223333333344444444
-		$revision = ord($sid[0]);
-		$numberSubID = ord($sid[1]);
-
-		$subIdStart = 8; // 1 + 1 + 6
-		$subIdLength = 4;
-		if (strlen($sid) !== $subIdStart + $subIdLength * $numberSubID) {
-			// Incorrect number of bytes present.
-			return '';
-		}
-
-		// 6 bytes = 48 bits can be represented using floats without loss of
-		// precision (see https://gist.github.com/bantu/886ac680b0aef5812f71)
-		$iav = number_format(hexdec(bin2hex(substr($sid, 2, 6))), 0, '', '');
-
-		$subIDs = array();
-		for ($i = 0; $i < $numberSubID; $i++) {
-			$subID = unpack('V', substr($sid, $subIdStart + $subIdLength * $i, $subIdLength));
-			$subIDs[] = sprintf('%u', $subID[1]);
-		}
-
-		// Result for example above: S-1-5-21-249921958-728525901-1594176202
-		return sprintf('S-%d-%s-%s', $revision, $iav, implode('-', $subIDs));
-	}
-
-	/**
-	 * checks if the given DN is part of the given base DN(s)
-	 * @param string $dn the DN
-	 * @param string[] $bases array containing the allowed base DN or DNs
-	 * @return bool
-	 */
-	public function isDNPartOfBase($dn, $bases) {
-		$belongsToBase = false;
-		$bases = $this->helper->sanitizeDN($bases);
-
-		foreach($bases as $base) {
-			$belongsToBase = true;
-			if(mb_strripos($dn, $base, 0, 'UTF-8') !== (mb_strlen($dn, 'UTF-8')-mb_strlen($base, 'UTF-8'))) {
-				$belongsToBase = false;
-			}
-			if($belongsToBase) {
-				break;
-			}
-		}
-		return $belongsToBase;
-	}
-
-	/**
-	 * resets a running Paged Search operation
-	 */
-	private function abandonPagedSearch() {
-		if($this->connection->hasPagedResultSupport) {
-			$cr = $this->connection->getConnectionResource();
-			$this->invokeLDAPMethod('controlPagedResult', $cr, 0, false, $this->lastCookie);
-			$this->getPagedSearchResultState();
-			$this->lastCookie = '';
-			$this->cookies = array();
-		}
-	}
-
-	/**
-	 * get a cookie for the next LDAP paged search
-	 * @param string $base a string with the base DN for the search
-	 * @param string $filter the search filter to identify the correct search
-	 * @param int $limit the limit (or 'pageSize'), to identify the correct search well
-	 * @param int $offset the offset for the new search to identify the correct search really good
-	 * @return string containing the key or empty if none is cached
-	 */
-	private function getPagedResultCookie($base, $filter, $limit, $offset) {
-		if($offset === 0) {
-			return '';
-		}
-		$offset -= $limit;
-		//we work with cache here
-		$cacheKey = 'lc' . crc32($base) . '-' . crc32($filter) . '-' . intval($limit) . '-' . intval($offset);
-		$cookie = '';
-		if(isset($this->cookies[$cacheKey])) {
-			$cookie = $this->cookies[$cacheKey];
-			if(is_null($cookie)) {
-				$cookie = '';
-			}
-		}
-		return $cookie;
-	}
-
-	/**
-	 * checks whether an LDAP paged search operation has more pages that can be
-	 * retrieved, typically when offset and limit are provided.
-	 *
-	 * Be very careful to use it: the last cookie value, which is inspected, can
-	 * be reset by other operations. Best, call it immediately after a search(),
-	 * searchUsers() or searchGroups() call. count-methods are probably safe as
-	 * well. Don't rely on it with any fetchList-method.
-	 * @return bool
-	 */
-	public function hasMoreResults() {
-		if(!$this->connection->hasPagedResultSupport) {
-			return false;
-		}
-
-		if(empty($this->lastCookie) && $this->lastCookie !== '0') {
-			// as in RFC 2696, when all results are returned, the cookie will
-			// be empty.
-			return false;
-		}
-
-		return true;
-	}
-
-	/**
-	 * set a cookie for LDAP paged search run
-	 * @param string $base a string with the base DN for the search
-	 * @param string $filter the search filter to identify the correct search
-	 * @param int $limit the limit (or 'pageSize'), to identify the correct search well
-	 * @param int $offset the offset for the run search to identify the correct search really good
-	 * @param string $cookie string containing the cookie returned by ldap_control_paged_result_response
-	 * @return void
-	 */
-	private function setPagedResultCookie($base, $filter, $limit, $offset, $cookie) {
-		// allow '0' for 389ds
-		if(!empty($cookie) || $cookie === '0') {
-			$cacheKey = 'lc' . crc32($base) . '-' . crc32($filter) . '-' .intval($limit) . '-' . intval($offset);
-			$this->cookies[$cacheKey] = $cookie;
-			$this->lastCookie = $cookie;
-		}
-	}
-
-	/**
-	 * Check whether the most recent paged search was successful. It flushed the state var. Use it always after a possible paged search.
-	 * @return boolean|null true on success, null or false otherwise
-	 */
-	public function getPagedSearchResultState() {
-		$result = $this->pagedSearchedSuccessful;
-		$this->pagedSearchedSuccessful = null;
-		return $result;
-	}
-
-	/**
-	 * Prepares a paged search, if possible
-	 * @param string $filter the LDAP filter for the search
-	 * @param string[] $bases an array containing the LDAP subtree(s) that shall be searched
-	 * @param string[] $attr optional, when a certain attribute shall be filtered outside
-	 * @param int $limit
-	 * @param int $offset
-	 * @return bool|true
-	 */
-	private function initPagedSearch($filter, $bases, $attr, $limit, $offset) {
-		$pagedSearchOK = false;
-		if($this->connection->hasPagedResultSupport && ($limit !== 0)) {
-			$offset = intval($offset); //can be null
-			\OCP\Util::writeLog('user_ldap',
-				'initializing paged search for  Filter '.$filter.' base '.print_r($bases, true)
-				.' attr '.print_r($attr, true). ' limit ' .$limit.' offset '.$offset,
-				\OCP\Util::DEBUG);
-			//get the cookie from the search for the previous search, required by LDAP
-			foreach($bases as $base) {
-
-				$cookie = $this->getPagedResultCookie($base, $filter, $limit, $offset);
-				if(empty($cookie) && $cookie !== "0" && ($offset > 0)) {
-					// no cookie known, although the offset is not 0. Maybe cache run out. We need
-					// to start all over *sigh* (btw, Dear Reader, did you know LDAP paged
-					// searching was designed by MSFT?)
-					// 		Lukas: No, but thanks to reading that source I finally know!
-					// '0' is valid, because 389ds
-					$reOffset = ($offset - $limit) < 0 ? 0 : $offset - $limit;
-					//a bit recursive, $offset of 0 is the exit
-					\OCP\Util::writeLog('user_ldap', 'Looking for cookie L/O '.$limit.'/'.$reOffset, \OCP\Util::INFO);
-					$this->search($filter, array($base), $attr, $limit, $reOffset, true);
-					$cookie = $this->getPagedResultCookie($base, $filter, $limit, $offset);
-					//still no cookie? obviously, the server does not like us. Let's skip paging efforts.
-					//TODO: remember this, probably does not change in the next request...
-					if(empty($cookie) && $cookie !== '0') {
-						// '0' is valid, because 389ds
-						$cookie = null;
-					}
-				}
-				if(!is_null($cookie)) {
-					//since offset = 0, this is a new search. We abandon other searches that might be ongoing.
-					$this->abandonPagedSearch();
-					$pagedSearchOK = $this->invokeLDAPMethod('controlPagedResult',
-						$this->connection->getConnectionResource(), $limit,
-						false, $cookie);
-					if(!$pagedSearchOK) {
-						return false;
-					}
-					\OCP\Util::writeLog('user_ldap', 'Ready for a paged search', \OCP\Util::DEBUG);
-				} else {
-					\OCP\Util::writeLog('user_ldap',
-						'No paged search for us, Cpt., Limit '.$limit.' Offset '.$offset,
-						\OCP\Util::INFO);
-				}
-
-			}
-		/* ++ Fixing RHDS searches with pages with zero results ++
+            \OC::$server->getLogger()->info(
+                'Passed string does not resemble a valid GUID. Known UUID ' .
+                '({uuid}) probably does not match UUID configuration.',
+                [ 'app' => 'user_ldap', 'uuid' => $guid ]
+            );
+            return $guid;
+        }
+        for($i=0; $i < 3; $i++) {
+            $pairs = str_split($blocks[$i], 2);
+            $pairs = array_reverse($pairs);
+            $blocks[$i] = implode('', $pairs);
+        }
+        for($i=0; $i < 5; $i++) {
+            $pairs = str_split($blocks[$i], 2);
+            $blocks[$i] = '\\' . implode('\\', $pairs);
+        }
+        return implode('', $blocks);
+    }
+
+    /**
+     * gets a SID of the domain of the given dn
+     * @param string $dn
+     * @return string|bool
+     */
+    public function getSID($dn) {
+        $domainDN = $this->getDomainDNFromDN($dn);
+        $cacheKey = 'getSID-'.$domainDN;
+        $sid = $this->connection->getFromCache($cacheKey);
+        if(!is_null($sid)) {
+            return $sid;
+        }
+
+        $objectSid = $this->readAttribute($domainDN, 'objectsid');
+        if(!is_array($objectSid) || empty($objectSid)) {
+            $this->connection->writeToCache($cacheKey, false);
+            return false;
+        }
+        $domainObjectSid = $this->convertSID2Str($objectSid[0]);
+        $this->connection->writeToCache($cacheKey, $domainObjectSid);
+
+        return $domainObjectSid;
+    }
+
+    /**
+     * converts a binary SID into a string representation
+     * @param string $sid
+     * @return string
+     */
+    public function convertSID2Str($sid) {
+        // The format of a SID binary string is as follows:
+        // 1 byte for the revision level
+        // 1 byte for the number n of variable sub-ids
+        // 6 bytes for identifier authority value
+        // n*4 bytes for n sub-ids
+        //
+        // Example: 010400000000000515000000a681e50e4d6c6c2bca32055f
+        //  Legend: RRNNAAAAAAAAAAAA11111111222222223333333344444444
+        $revision = ord($sid[0]);
+        $numberSubID = ord($sid[1]);
+
+        $subIdStart = 8; // 1 + 1 + 6
+        $subIdLength = 4;
+        if (strlen($sid) !== $subIdStart + $subIdLength * $numberSubID) {
+            // Incorrect number of bytes present.
+            return '';
+        }
+
+        // 6 bytes = 48 bits can be represented using floats without loss of
+        // precision (see https://gist.github.com/bantu/886ac680b0aef5812f71)
+        $iav = number_format(hexdec(bin2hex(substr($sid, 2, 6))), 0, '', '');
+
+        $subIDs = array();
+        for ($i = 0; $i < $numberSubID; $i++) {
+            $subID = unpack('V', substr($sid, $subIdStart + $subIdLength * $i, $subIdLength));
+            $subIDs[] = sprintf('%u', $subID[1]);
+        }
+
+        // Result for example above: S-1-5-21-249921958-728525901-1594176202
+        return sprintf('S-%d-%s-%s', $revision, $iav, implode('-', $subIDs));
+    }
+
+    /**
+     * checks if the given DN is part of the given base DN(s)
+     * @param string $dn the DN
+     * @param string[] $bases array containing the allowed base DN or DNs
+     * @return bool
+     */
+    public function isDNPartOfBase($dn, $bases) {
+        $belongsToBase = false;
+        $bases = $this->helper->sanitizeDN($bases);
+
+        foreach($bases as $base) {
+            $belongsToBase = true;
+            if(mb_strripos($dn, $base, 0, 'UTF-8') !== (mb_strlen($dn, 'UTF-8')-mb_strlen($base, 'UTF-8'))) {
+                $belongsToBase = false;
+            }
+            if($belongsToBase) {
+                break;
+            }
+        }
+        return $belongsToBase;
+    }
+
+    /**
+     * resets a running Paged Search operation
+     */
+    private function abandonPagedSearch() {
+        if($this->connection->hasPagedResultSupport) {
+            $cr = $this->connection->getConnectionResource();
+            $this->invokeLDAPMethod('controlPagedResult', $cr, 0, false, $this->lastCookie);
+            $this->getPagedSearchResultState();
+            $this->lastCookie = '';
+            $this->cookies = array();
+        }
+    }
+
+    /**
+     * get a cookie for the next LDAP paged search
+     * @param string $base a string with the base DN for the search
+     * @param string $filter the search filter to identify the correct search
+     * @param int $limit the limit (or 'pageSize'), to identify the correct search well
+     * @param int $offset the offset for the new search to identify the correct search really good
+     * @return string containing the key or empty if none is cached
+     */
+    private function getPagedResultCookie($base, $filter, $limit, $offset) {
+        if($offset === 0) {
+            return '';
+        }
+        $offset -= $limit;
+        //we work with cache here
+        $cacheKey = 'lc' . crc32($base) . '-' . crc32($filter) . '-' . intval($limit) . '-' . intval($offset);
+        $cookie = '';
+        if(isset($this->cookies[$cacheKey])) {
+            $cookie = $this->cookies[$cacheKey];
+            if(is_null($cookie)) {
+                $cookie = '';
+            }
+        }
+        return $cookie;
+    }
+
+    /**
+     * checks whether an LDAP paged search operation has more pages that can be
+     * retrieved, typically when offset and limit are provided.
+     *
+     * Be very careful to use it: the last cookie value, which is inspected, can
+     * be reset by other operations. Best, call it immediately after a search(),
+     * searchUsers() or searchGroups() call. count-methods are probably safe as
+     * well. Don't rely on it with any fetchList-method.
+     * @return bool
+     */
+    public function hasMoreResults() {
+        if(!$this->connection->hasPagedResultSupport) {
+            return false;
+        }
+
+        if(empty($this->lastCookie) && $this->lastCookie !== '0') {
+            // as in RFC 2696, when all results are returned, the cookie will
+            // be empty.
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * set a cookie for LDAP paged search run
+     * @param string $base a string with the base DN for the search
+     * @param string $filter the search filter to identify the correct search
+     * @param int $limit the limit (or 'pageSize'), to identify the correct search well
+     * @param int $offset the offset for the run search to identify the correct search really good
+     * @param string $cookie string containing the cookie returned by ldap_control_paged_result_response
+     * @return void
+     */
+    private function setPagedResultCookie($base, $filter, $limit, $offset, $cookie) {
+        // allow '0' for 389ds
+        if(!empty($cookie) || $cookie === '0') {
+            $cacheKey = 'lc' . crc32($base) . '-' . crc32($filter) . '-' .intval($limit) . '-' . intval($offset);
+            $this->cookies[$cacheKey] = $cookie;
+            $this->lastCookie = $cookie;
+        }
+    }
+
+    /**
+     * Check whether the most recent paged search was successful. It flushed the state var. Use it always after a possible paged search.
+     * @return boolean|null true on success, null or false otherwise
+     */
+    public function getPagedSearchResultState() {
+        $result = $this->pagedSearchedSuccessful;
+        $this->pagedSearchedSuccessful = null;
+        return $result;
+    }
+
+    /**
+     * Prepares a paged search, if possible
+     * @param string $filter the LDAP filter for the search
+     * @param string[] $bases an array containing the LDAP subtree(s) that shall be searched
+     * @param string[] $attr optional, when a certain attribute shall be filtered outside
+     * @param int $limit
+     * @param int $offset
+     * @return bool|true
+     */
+    private function initPagedSearch($filter, $bases, $attr, $limit, $offset) {
+        $pagedSearchOK = false;
+        if($this->connection->hasPagedResultSupport && ($limit !== 0)) {
+            $offset = intval($offset); //can be null
+            \OCP\Util::writeLog('user_ldap',
+                'initializing paged search for  Filter '.$filter.' base '.print_r($bases, true)
+                .' attr '.print_r($attr, true). ' limit ' .$limit.' offset '.$offset,
+                \OCP\Util::DEBUG);
+            //get the cookie from the search for the previous search, required by LDAP
+            foreach($bases as $base) {
+
+                $cookie = $this->getPagedResultCookie($base, $filter, $limit, $offset);
+                if(empty($cookie) && $cookie !== "0" && ($offset > 0)) {
+                    // no cookie known, although the offset is not 0. Maybe cache run out. We need
+                    // to start all over *sigh* (btw, Dear Reader, did you know LDAP paged
+                    // searching was designed by MSFT?)
+                    // 		Lukas: No, but thanks to reading that source I finally know!
+                    // '0' is valid, because 389ds
+                    $reOffset = ($offset - $limit) < 0 ? 0 : $offset - $limit;
+                    //a bit recursive, $offset of 0 is the exit
+                    \OCP\Util::writeLog('user_ldap', 'Looking for cookie L/O '.$limit.'/'.$reOffset, \OCP\Util::INFO);
+                    $this->search($filter, array($base), $attr, $limit, $reOffset, true);
+                    $cookie = $this->getPagedResultCookie($base, $filter, $limit, $offset);
+                    //still no cookie? obviously, the server does not like us. Let's skip paging efforts.
+                    //TODO: remember this, probably does not change in the next request...
+                    if(empty($cookie) && $cookie !== '0') {
+                        // '0' is valid, because 389ds
+                        $cookie = null;
+                    }
+                }
+                if(!is_null($cookie)) {
+                    //since offset = 0, this is a new search. We abandon other searches that might be ongoing.
+                    $this->abandonPagedSearch();
+                    $pagedSearchOK = $this->invokeLDAPMethod('controlPagedResult',
+                        $this->connection->getConnectionResource(), $limit,
+                        false, $cookie);
+                    if(!$pagedSearchOK) {
+                        return false;
+                    }
+                    \OCP\Util::writeLog('user_ldap', 'Ready for a paged search', \OCP\Util::DEBUG);
+                } else {
+                    \OCP\Util::writeLog('user_ldap',
+                        'No paged search for us, Cpt., Limit '.$limit.' Offset '.$offset,
+                        \OCP\Util::INFO);
+                }
+
+            }
+        /* ++ Fixing RHDS searches with pages with zero results ++
 		 * We coudn't get paged searches working with our RHDS for login ($limit = 0),
 		 * due to pages with zero results.
 		 * So we added "&& !empty($this->lastCookie)" to this test to ignore pagination
 		 * if we don't have a previous paged search.
 		 */
-		} else if($this->connection->hasPagedResultSupport && $limit === 0 && !empty($this->lastCookie)) {
-			// a search without limit was requested. However, if we do use
-			// Paged Search once, we always must do it. This requires us to
-			// initialize it with the configured page size.
-			$this->abandonPagedSearch();
-			// in case someone set it to 0 … use 500, otherwise no results will
-			// be returned.
-			$pageSize = intval($this->connection->ldapPagingSize) > 0 ? intval($this->connection->ldapPagingSize) : 500;
-			$pagedSearchOK = $this->invokeLDAPMethod('controlPagedResult',
-				$this->connection->getConnectionResource(),
-				$pageSize, false, '');
-		}
-
-		return $pagedSearchOK;
-	}
+        } else if($this->connection->hasPagedResultSupport && $limit === 0 && !empty($this->lastCookie)) {
+            // a search without limit was requested. However, if we do use
+            // Paged Search once, we always must do it. This requires us to
+            // initialize it with the configured page size.
+            $this->abandonPagedSearch();
+            // in case someone set it to 0 … use 500, otherwise no results will
+            // be returned.
+            $pageSize = intval($this->connection->ldapPagingSize) > 0 ? intval($this->connection->ldapPagingSize) : 500;
+            $pagedSearchOK = $this->invokeLDAPMethod('controlPagedResult',
+                $this->connection->getConnectionResource(),
+                $pageSize, false, '');
+        }
+
+        return $pagedSearchOK;
+    }
 
 }

Spacing +164 added lines, -164 removed lines

@@ -112,7 +112,7 @@ 
 	 * @return AbstractMapping
 	 */
 	public function getUserMapper() {
-		if(is_null($this->userMapper)) {
+		if (is_null($this->userMapper)) {
 			throw new \Exception('UserMapper was not assigned to this Access instance.');
 		}
 		return $this->userMapper;
@@ -132,7 +132,7 @@ 
 	 * @return AbstractMapping
 	 */
 	public function getGroupMapper() {
-		if(is_null($this->groupMapper)) {
+		if (is_null($this->groupMapper)) {
 			throw new \Exception('GroupMapper was not assigned to this Access instance.');
 		}
 		return $this->groupMapper;
@@ -163,14 +163,14 @@ 
 	 *          array if $attr is empty, false otherwise
 	 */
 	public function readAttribute($dn, $attr, $filter = 'objectClass=*') {
-		if(!$this->checkConnection()) {
+		if (!$this->checkConnection()) {
 			\OCP\Util::writeLog('user_ldap',
 				'No LDAP Connector assigned, access impossible for readAttribute.',
 				\OCP\Util::WARN);
 			return false;
 		}
 		$cr = $this->connection->getConnectionResource();
-		if(!$this->ldap->isResource($cr)) {
+		if (!$this->ldap->isResource($cr)) {
 			//LDAP not available
 			\OCP\Util::writeLog('user_ldap', 'LDAP resource not available.', \OCP\Util::DEBUG);
 			return false;
@@ -193,7 +193,7 @@ 
 		$isRangeRequest = false;
 		do {
 			$result = $this->executeRead($cr, $dn, $attrToRead, $filter, $maxResults);
-			if(is_bool($result)) {
+			if (is_bool($result)) {
 				// when an exists request was run and it was successful, an empty
 				// array must be returned
 				return $result ? [] : false;
@@ -210,22 +210,22 @@ 
 			$result = $this->extractRangeData($result, $attr);
 			if (!empty($result)) {
 				$normalizedResult = $this->extractAttributeValuesFromResult(
-					[ $attr => $result['values'] ],
+					[$attr => $result['values']],
 					$attr
 				);
 				$values = array_merge($values, $normalizedResult);
 
-				if($result['rangeHigh'] === '*') {
+				if ($result['rangeHigh'] === '*') {
 					// when server replies with * as high range value, there are
 					// no more results left
 					return $values;
 				} else {
-					$low  = $result['rangeHigh'] + 1;
-					$attrToRead = $result['attributeName'] . ';range=' . $low . '-*';
+					$low = $result['rangeHigh'] + 1;
+					$attrToRead = $result['attributeName'].';range='.$low.'-*';
 					$isRangeRequest = true;
 				}
 			}
-		} while($isRangeRequest);
+		} while ($isRangeRequest);
 
 		\OCP\Util::writeLog('user_ldap', 'Requested attribute '.$attr.' not found for '.$dn, \OCP\Util::DEBUG);
 		return false;
@@ -250,13 +250,13 @@ 
 		if (!$this->ldap->isResource($rr)) {
 			if ($attribute !== '') {
 				//do not throw this message on userExists check, irritates
-				\OCP\Util::writeLog('user_ldap', 'readAttribute failed for DN ' . $dn, \OCP\Util::DEBUG);
+				\OCP\Util::writeLog('user_ldap', 'readAttribute failed for DN '.$dn, \OCP\Util::DEBUG);
 			}
 			//in case an error occurs , e.g. object does not exist
 			return false;
 		}
 		if ($attribute === '' && ($filter === 'objectclass=*' || $this->invokeLDAPMethod('countEntries', $cr, $rr) === 1)) {
-			\OCP\Util::writeLog('user_ldap', 'readAttribute: ' . $dn . ' found', \OCP\Util::DEBUG);
+			\OCP\Util::writeLog('user_ldap', 'readAttribute: '.$dn.' found', \OCP\Util::DEBUG);
 			return true;
 		}
 		$er = $this->invokeLDAPMethod('firstEntry', $cr, $rr);
@@ -281,12 +281,12 @@ 
 	 */
 	public function extractAttributeValuesFromResult($result, $attribute) {
 		$values = [];
-		if(isset($result[$attribute]) && $result[$attribute]['count'] > 0) {
+		if (isset($result[$attribute]) && $result[$attribute]['count'] > 0) {
 			$lowercaseAttribute = strtolower($attribute);
-			for($i=0;$i<$result[$attribute]['count'];$i++) {
-				if($this->resemblesDN($attribute)) {
+			for ($i = 0; $i < $result[$attribute]['count']; $i++) {
+				if ($this->resemblesDN($attribute)) {
 					$values[] = $this->helper->sanitizeDN($result[$attribute][$i]);
-				} elseif($lowercaseAttribute === 'objectguid' || $lowercaseAttribute === 'guid') {
+				} elseif ($lowercaseAttribute === 'objectguid' || $lowercaseAttribute === 'guid') {
 					$values[] = $this->convertObjectGUID2Str($result[$attribute][$i]);
 				} else {
 					$values[] = $result[$attribute][$i];
@@ -308,10 +308,10 @@ 
 	 */
 	public function extractRangeData($result, $attribute) {
 		$keys = array_keys($result);
-		foreach($keys as $key) {
-			if($key !== $attribute && strpos($key, $attribute) === 0) {
+		foreach ($keys as $key) {
+			if ($key !== $attribute && strpos($key, $attribute) === 0) {
 				$queryData = explode(';', $key);
-				if(strpos($queryData[1], 'range=') === 0) {
+				if (strpos($queryData[1], 'range=') === 0) {
 					$high = substr($queryData[1], 1 + strpos($queryData[1], '-'));
 					$data = [
 						'values' => $result[$key],
@@ -336,18 +336,18 @@ 
 	 * @throws \Exception
 	 */
 	public function setPassword($userDN, $password) {
-		if(intval($this->connection->turnOnPasswordChange) !== 1) {
+		if (intval($this->connection->turnOnPasswordChange) !== 1) {
 			throw new \Exception('LDAP password changes are disabled.');
 		}
 		$cr = $this->connection->getConnectionResource();
-		if(!$this->ldap->isResource($cr)) {
+		if (!$this->ldap->isResource($cr)) {
 			//LDAP not available
 			\OCP\Util::writeLog('user_ldap', 'LDAP resource not available.', \OCP\Util::DEBUG);
 			return false;
 		}
 		try {
 			return @$this->invokeLDAPMethod('modReplace', $cr, $userDN, $password);
-		} catch(ConstraintViolationException $e) {
+		} catch (ConstraintViolationException $e) {
 			throw new HintException('Password change rejected.', \OC::$server->getL10N('user_ldap')->t('Password change rejected. Hint: ').$e->getMessage(), $e->getCode());
 		}
 	}
@@ -389,17 +389,17 @@ 
 	 */
 	public function getDomainDNFromDN($dn) {
 		$allParts = $this->ldap->explodeDN($dn, 0);
-		if($allParts === false) {
+		if ($allParts === false) {
 			//not a valid DN
 			return '';
 		}
 		$domainParts = array();
 		$dcFound = false;
-		foreach($allParts as $part) {
-			if(!$dcFound && strpos($part, 'dc=') === 0) {
+		foreach ($allParts as $part) {
+			if (!$dcFound && strpos($part, 'dc=') === 0) {
 				$dcFound = true;
 			}
-			if($dcFound) {
+			if ($dcFound) {
 				$domainParts[] = $part;
 			}
 		}
@@ -426,7 +426,7 @@ 
 
 		//Check whether the DN belongs to the Base, to avoid issues on multi-
 		//server setups
-		if(is_string($fdn) && $this->isDNPartOfBase($fdn, $this->connection->ldapBaseUsers)) {
+		if (is_string($fdn) && $this->isDNPartOfBase($fdn, $this->connection->ldapBaseUsers)) {
 			return $fdn;
 		}
 
@@ -443,7 +443,7 @@ 
 		//To avoid bypassing the base DN settings under certain circumstances
 		//with the group support, check whether the provided DN matches one of
 		//the given Bases
-		if(!$this->isDNPartOfBase($fdn, $this->connection->ldapBaseGroups)) {
+		if (!$this->isDNPartOfBase($fdn, $this->connection->ldapBaseGroups)) {
 			return false;
 		}
 
@@ -460,11 +460,11 @@ 
 	 */
 	public function groupsMatchFilter($groupDNs) {
 		$validGroupDNs = [];
-		foreach($groupDNs as $dn) {
+		foreach ($groupDNs as $dn) {
 			$cacheKey = 'groupsMatchFilter-'.$dn;
 			$groupMatchFilter = $this->connection->getFromCache($cacheKey);
-			if(!is_null($groupMatchFilter)) {
-				if($groupMatchFilter) {
+			if (!is_null($groupMatchFilter)) {
+				if ($groupMatchFilter) {
 					$validGroupDNs[] = $dn;
 				}
 				continue;
@@ -472,13 +472,13 @@ 
 
 			// Check the base DN first. If this is not met already, we don't
 			// need to ask the server at all.
-			if(!$this->isDNPartOfBase($dn, $this->connection->ldapBaseGroups)) {
+			if (!$this->isDNPartOfBase($dn, $this->connection->ldapBaseGroups)) {
 				$this->connection->writeToCache($cacheKey, false);
 				continue;
 			}
 
 			$result = $this->readAttribute($dn, 'cn', $this->connection->ldapGroupFilter);
-			if(is_array($result)) {
+			if (is_array($result)) {
 				$this->connection->writeToCache($cacheKey, true);
 				$validGroupDNs[] = $dn;
 			} else {
@@ -499,7 +499,7 @@ 
 		//To avoid bypassing the base DN settings under certain circumstances
 		//with the group support, check whether the provided DN matches one of
 		//the given Bases
-		if(!$this->isDNPartOfBase($fdn, $this->connection->ldapBaseUsers)) {
+		if (!$this->isDNPartOfBase($fdn, $this->connection->ldapBaseUsers)) {
 			return false;
 		}
 
@@ -514,7 +514,7 @@ 
 	 * @return string|false with with the name to use in Nextcloud
 	 */
 	public function dn2ocname($fdn, $ldapName = null, $isUser = true) {
-		if($isUser) {
+		if ($isUser) {
 			$mapper = $this->getUserMapper();
 			$nameAttribute = $this->connection->ldapUserDisplayName;
 		} else {
@@ -524,15 +524,15 @@ 
 
 		//let's try to retrieve the Nextcloud name from the mappings table
 		$ocName = $mapper->getNameByDN($fdn);
-		if(is_string($ocName)) {
+		if (is_string($ocName)) {
 			return $ocName;
 		}
 
 		//second try: get the UUID and check if it is known. Then, update the DN and return the name.
 		$uuid = $this->getUUID($fdn, $isUser);
-		if(is_string($uuid)) {
+		if (is_string($uuid)) {
 			$ocName = $mapper->getNameByUUID($uuid);
-			if(is_string($ocName)) {
+			if (is_string($ocName)) {
 				$mapper->setDNbyUUID($fdn, $uuid);
 				return $ocName;
 			}
@@ -542,16 +542,16 @@ 
 			return false;
 		}
 
-		if(is_null($ldapName)) {
+		if (is_null($ldapName)) {
 			$ldapName = $this->readAttribute($fdn, $nameAttribute);
-			if(!isset($ldapName[0]) && empty($ldapName[0])) {
+			if (!isset($ldapName[0]) && empty($ldapName[0])) {
 				\OCP\Util::writeLog('user_ldap', 'No or empty name for '.$fdn.'.', \OCP\Util::INFO);
 				return false;
 			}
 			$ldapName = $ldapName[0];
 		}
 
-		if($isUser) {
+		if ($isUser) {
 			$usernameAttribute = strval($this->connection->ldapExpertUsernameAttr);
 			if ($usernameAttribute !== '') {
 				$username = $this->readAttribute($fdn, $usernameAttribute);
@@ -570,9 +570,9 @@ 
 		// outside of core user management will still cache the user as non-existing.
 		$originalTTL = $this->connection->ldapCacheTTL;
 		$this->connection->setConfiguration(array('ldapCacheTTL' => 0));
-		if(($isUser && !\OCP\User::userExists($intName))
+		if (($isUser && !\OCP\User::userExists($intName))
 			|| (!$isUser && !\OC::$server->getGroupManager()->groupExists($intName))) {
-			if($mapper->map($fdn, $intName, $uuid)) {
+			if ($mapper->map($fdn, $intName, $uuid)) {
 				$this->connection->setConfiguration(array('ldapCacheTTL' => $originalTTL));
 				return $intName;
 			}
@@ -580,7 +580,7 @@ 
 		$this->connection->setConfiguration(array('ldapCacheTTL' => $originalTTL));
 
 		$altName = $this->createAltInternalOwnCloudName($intName, $isUser);
-		if(is_string($altName) && $mapper->map($fdn, $altName, $uuid)) {
+		if (is_string($altName) && $mapper->map($fdn, $altName, $uuid)) {
 			return $altName;
 		}
 
@@ -617,7 +617,7 @@ 
 	 * @return array
 	 */
 	private function ldap2NextcloudNames($ldapObjects, $isUsers) {
-		if($isUsers) {
+		if ($isUsers) {
 			$nameAttribute = $this->connection->ldapUserDisplayName;
 			$sndAttribute  = $this->connection->ldapUserDisplayName2;
 		} else {
@@ -625,9 +625,9 @@ 
 		}
 		$nextcloudNames = array();
 
-		foreach($ldapObjects as $ldapObject) {
+		foreach ($ldapObjects as $ldapObject) {
 			$nameByLDAP = null;
-			if(    isset($ldapObject[$nameAttribute])
+			if (isset($ldapObject[$nameAttribute])
 				&& is_array($ldapObject[$nameAttribute])
 				&& isset($ldapObject[$nameAttribute][0])
 			) {
@@ -636,12 +636,12 @@ 
 			}
 
 			$ncName = $this->dn2ocname($ldapObject['dn'][0], $nameByLDAP, $isUsers);
-			if($ncName) {
+			if ($ncName) {
 				$nextcloudNames[] = $ncName;
-				if($isUsers) {
+				if ($isUsers) {
 					//cache the user names so it does not need to be retrieved
 					//again later (e.g. sharing dialogue).
-					if(is_null($nameByLDAP)) {
+					if (is_null($nameByLDAP)) {
 						continue;
 					}
 					$sndName = isset($ldapObject[$sndAttribute][0])
@@ -679,7 +679,7 @@ 
 	 */
 	public function cacheUserDisplayName($ocName, $displayName, $displayName2 = '') {
 		$user = $this->userManager->get($ocName);
-		if($user === null) {
+		if ($user === null) {
 			return;
 		}
 		$displayName = $user->composeAndStoreDisplayName($displayName, $displayName2);
@@ -699,9 +699,9 @@ 
 		$attempts = 0;
 		//while loop is just a precaution. If a name is not generated within
 		//20 attempts, something else is very wrong. Avoids infinite loop.
-		while($attempts < 20){
-			$altName = $name . '_' . rand(1000,9999);
-			if(!\OCP\User::userExists($altName)) {
+		while ($attempts < 20) {
+			$altName = $name.'_'.rand(1000, 9999);
+			if (!\OCP\User::userExists($altName)) {
 				return $altName;
 			}
 			$attempts++;
@@ -723,25 +723,25 @@ 
 	 */
 	private function _createAltInternalOwnCloudNameForGroups($name) {
 		$usedNames = $this->groupMapper->getNamesBySearch($name, "", '_%');
-		if(!($usedNames) || count($usedNames) === 0) {
+		if (!($usedNames) || count($usedNames) === 0) {
 			$lastNo = 1; //will become name_2
 		} else {
 			natsort($usedNames);
 			$lastName = array_pop($usedNames);
 			$lastNo = intval(substr($lastName, strrpos($lastName, '_') + 1));
 		}
-		$altName = $name.'_'.strval($lastNo+1);
+		$altName = $name.'_'.strval($lastNo + 1);
 		unset($usedNames);
 
 		$attempts = 1;
-		while($attempts < 21){
+		while ($attempts < 21) {
 			// Check to be really sure it is unique
 			// while loop is just a precaution. If a name is not generated within
 			// 20 attempts, something else is very wrong. Avoids infinite loop.
-			if(!\OC::$server->getGroupManager()->groupExists($altName)) {
+			if (!\OC::$server->getGroupManager()->groupExists($altName)) {
 				return $altName;
 			}
-			$altName = $name . '_' . ($lastNo + $attempts);
+			$altName = $name.'_'.($lastNo + $attempts);
 			$attempts++;
 		}
 		return false;
@@ -756,7 +756,7 @@ 
 	private function createAltInternalOwnCloudName($name, $isUser) {
 		$originalTTL = $this->connection->ldapCacheTTL;
 		$this->connection->setConfiguration(array('ldapCacheTTL' => 0));
-		if($isUser) {
+		if ($isUser) {
 			$altName = $this->_createAltInternalOwnCloudNameForUsers($name);
 		} else {
 			$altName = $this->_createAltInternalOwnCloudNameForGroups($name);
@@ -814,20 +814,20 @@ 
 	 * and their values
 	 * @param array $ldapRecords
 	 */
-	public function batchApplyUserAttributes(array $ldapRecords){
+	public function batchApplyUserAttributes(array $ldapRecords) {
 		$displayNameAttribute = strtolower($this->connection->ldapUserDisplayName);
-		foreach($ldapRecords as $userRecord) {
-			if(!isset($userRecord[$displayNameAttribute])) {
+		foreach ($ldapRecords as $userRecord) {
+			if (!isset($userRecord[$displayNameAttribute])) {
 				// displayName is obligatory
 				continue;
 			}
-			$ocName  = $this->dn2ocname($userRecord['dn'][0]);
-			if($ocName === false) {
+			$ocName = $this->dn2ocname($userRecord['dn'][0]);
+			if ($ocName === false) {
 				continue;
 			}
 			$this->cacheUserExists($ocName);
 			$user = $this->userManager->get($ocName);
-			if($user instanceof OfflineUser) {
+			if ($user instanceof OfflineUser) {
 				$user->unmark();
 				$user = $this->userManager->get($ocName);
 			}
@@ -859,8 +859,8 @@ 
 	 * @return array
 	 */
 	private function fetchList($list, $manyAttributes) {
-		if(is_array($list)) {
-			if($manyAttributes) {
+		if (is_array($list)) {
+			if ($manyAttributes) {
 				return $list;
 			} else {
 				$list = array_reduce($list, function($carry, $item) {
@@ -958,7 +958,7 @@ 
 		// php no longer supports call-time pass-by-reference
 		// thus cannot support controlPagedResultResponse as the third argument
 		// is a reference
-		$doMethod = function () use ($command, &$arguments) {
+		$doMethod = function() use ($command, &$arguments) {
 			if ($command == 'controlPagedResultResponse') {
 				throw new \InvalidArgumentException('Invoker does not support controlPagedResultResponse, call LDAP Wrapper directly instead.');
 			} else {
@@ -976,7 +976,7 @@ 
 			$this->connection->resetConnectionResource();
 			$cr = $this->connection->getConnectionResource();
 
-			if(!$this->ldap->isResource($cr)) {
+			if (!$this->ldap->isResource($cr)) {
 				// Seems like we didn't find any resource.
 				\OCP\Util::writeLog('user_ldap', "Could not $command, because resource is missing.", \OCP\Util::DEBUG);
 				throw $e;
@@ -997,13 +997,13 @@ 
 	 * @throws \OC\ServerNotAvailableException
 	 */
 	private function executeSearch($filter, $base, &$attr = null, $limit = null, $offset = null) {
-		if(!is_null($attr) && !is_array($attr)) {
+		if (!is_null($attr) && !is_array($attr)) {
 			$attr = array(mb_strtolower($attr, 'UTF-8'));
 		}
 
 		// See if we have a resource, in case not cancel with message
 		$cr = $this->connection->getConnectionResource();
-		if(!$this->ldap->isResource($cr)) {
+		if (!$this->ldap->isResource($cr)) {
 			// Seems like we didn't find any resource.
 			// Return an empty array just like before.
 			\OCP\Util::writeLog('user_ldap', 'Could not search, because resource is missing.', \OCP\Util::DEBUG);
@@ -1017,7 +1017,7 @@ 
 		$sr = $this->invokeLDAPMethod('search', $linkResources, $base, $filter, $attr);
 		// cannot use $cr anymore, might have changed in the previous call!
 		$error = $this->ldap->errno($this->connection->getConnectionResource());
-		if(!is_array($sr) || $error !== 0) {
+		if (!is_array($sr) || $error !== 0) {
 			\OCP\Util::writeLog('user_ldap', 'Attempt for Paging?  '.print_r($pagedSearchOK, true), \OCP\Util::ERROR);
 			return false;
 		}
@@ -1040,26 +1040,26 @@ 
 	 */
 	private function processPagedSearchStatus($sr, $filter, $base, $iFoundItems, $limit, $offset, $pagedSearchOK, $skipHandling) {
 		$cookie = null;
-		if($pagedSearchOK) {
+		if ($pagedSearchOK) {
 			$cr = $this->connection->getConnectionResource();
-			foreach($sr as $key => $res) {
-				if($this->ldap->controlPagedResultResponse($cr, $res, $cookie)) {
+			foreach ($sr as $key => $res) {
+				if ($this->ldap->controlPagedResultResponse($cr, $res, $cookie)) {
 					$this->setPagedResultCookie($base[$key], $filter, $limit, $offset, $cookie);
 				}
 			}
 
 			//browsing through prior pages to get the cookie for the new one
-			if($skipHandling) {
+			if ($skipHandling) {
 				return false;
 			}
 			// if count is bigger, then the server does not support
 			// paged search. Instead, he did a normal search. We set a
 			// flag here, so the callee knows how to deal with it.
-			if($iFoundItems <= $limit) {
+			if ($iFoundItems <= $limit) {
 				$this->pagedSearchedSuccessful = true;
 			}
 		} else {
-			if(!is_null($limit)) {
+			if (!is_null($limit)) {
 				\OCP\Util::writeLog('user_ldap', 'Paged search was not available', \OCP\Util::INFO);
 			}
 		}
@@ -1088,7 +1088,7 @@ 
 		\OCP\Util::writeLog('user_ldap', 'Count filter:  '.print_r($filter, true), \OCP\Util::DEBUG);
 
 		$limitPerPage = intval($this->connection->ldapPagingSize);
-		if(!is_null($limit) && $limit < $limitPerPage && $limit > 0) {
+		if (!is_null($limit) && $limit < $limitPerPage && $limit > 0) {
 			$limitPerPage = $limit;
 		}
 
@@ -1099,7 +1099,7 @@ 
 		do {
 			$search = $this->executeSearch($filter, $base, $attr,
 										   $limitPerPage, $offset);
-			if($search === false) {
+			if ($search === false) {
 				return $counter > 0 ? $counter : false;
 			}
 			list($sr, $pagedSearchOK) = $search;
@@ -1118,7 +1118,7 @@ 
 			 * Continue now depends on $hasMorePages value
 			 */
 			$continue = $pagedSearchOK && $hasMorePages;
-		} while($continue && (is_null($limit) || $limit <= 0 || $limit > $counter));
+		} while ($continue && (is_null($limit) || $limit <= 0 || $limit > $counter));
 
 		return $counter;
 	}
@@ -1130,7 +1130,7 @@ 
 	private function countEntriesInSearchResults($searchResults) {
 		$counter = 0;
 
-		foreach($searchResults as $res) {
+		foreach ($searchResults as $res) {
 			$count = intval($this->invokeLDAPMethod('countEntries', $this->connection->getConnectionResource(), $res));
 			$counter += $count;
 		}
@@ -1150,7 +1150,7 @@ 
 	 */
 	public function search($filter, $base, $attr = null, $limit = null, $offset = null, $skipHandling = false) {
 		$limitPerPage = intval($this->connection->ldapPagingSize);
-		if(!is_null($limit) && $limit < $limitPerPage && $limit > 0) {
+		if (!is_null($limit) && $limit < $limitPerPage && $limit > 0) {
 			$limitPerPage = $limit;
 		}
 
@@ -1164,13 +1164,13 @@ 
 		$savedoffset = $offset;
 		do {
 			$search = $this->executeSearch($filter, $base, $attr, $limitPerPage, $offset);
-			if($search === false) {
+			if ($search === false) {
 				return array();
 			}
 			list($sr, $pagedSearchOK) = $search;
 			$cr = $this->connection->getConnectionResource();
 
-			if($skipHandling) {
+			if ($skipHandling) {
 				//i.e. result do not need to be fetched, we just need the cookie
 				//thus pass 1 or any other value as $iFoundItems because it is not
 				//used
@@ -1181,7 +1181,7 @@ 
 			}
 
 			$iFoundItems = 0;
-			foreach($sr as $res) {
+			foreach ($sr as $res) {
 				$findings = array_merge($findings, $this->invokeLDAPMethod('getEntries', $cr, $res));
 				$iFoundItems = max($iFoundItems, $findings['count']);
 				unset($findings['count']);
@@ -1197,25 +1197,25 @@ 
 
 		// if we're here, probably no connection resource is returned.
 		// to make Nextcloud behave nicely, we simply give back an empty array.
-		if(is_null($findings)) {
+		if (is_null($findings)) {
 			return array();
 		}
 
-		if(!is_null($attr)) {
+		if (!is_null($attr)) {
 			$selection = array();
 			$i = 0;
-			foreach($findings as $item) {
-				if(!is_array($item)) {
+			foreach ($findings as $item) {
+				if (!is_array($item)) {
 					continue;
 				}
 				$item = \OCP\Util::mb_array_change_key_case($item, MB_CASE_LOWER, 'UTF-8');
-				foreach($attr as $key) {
+				foreach ($attr as $key) {
 					$key = mb_strtolower($key, 'UTF-8');
-					if(isset($item[$key])) {
-						if(is_array($item[$key]) && isset($item[$key]['count'])) {
+					if (isset($item[$key])) {
+						if (is_array($item[$key]) && isset($item[$key]['count'])) {
 							unset($item[$key]['count']);
 						}
-						if($key !== 'dn') {
+						if ($key !== 'dn') {
 							$selection[$i][$key] = $this->resemblesDN($key) ?
 								$this->helper->sanitizeDN($item[$key])
 								: $item[$key];
@@ -1232,7 +1232,7 @@ 
 		//we slice the findings, when
 		//a) paged search unsuccessful, though attempted
 		//b) no paged search, but limit set
-		if((!$this->getPagedSearchResultState()
+		if ((!$this->getPagedSearchResultState()
 			&& $pagedSearchOK)
 			|| (
 				!$pagedSearchOK
@@ -1249,7 +1249,7 @@ 
 	 * @return bool|mixed|string
 	 */
 	public function sanitizeUsername($name) {
-		if($this->connection->ldapIgnoreNamingRules) {
+		if ($this->connection->ldapIgnoreNamingRules) {
 			return $name;
 		}
 
@@ -1274,13 +1274,13 @@ 
 	*/
 	public function escapeFilterPart($input, $allowAsterisk = false) {
 		$asterisk = '';
-		if($allowAsterisk && strlen($input) > 0 && $input[0] === '*') {
+		if ($allowAsterisk && strlen($input) > 0 && $input[0] === '*') {
 			$asterisk = '*';
 			$input = mb_substr($input, 1, null, 'UTF-8');
 		}
 		$search  = array('*', '\\', '(', ')');
 		$replace = array('\\*', '\\\\', '\\(', '\\)');
-		return $asterisk . str_replace($search, $replace, $input);
+		return $asterisk.str_replace($search, $replace, $input);
 	}
 
 	/**
@@ -1310,13 +1310,13 @@ 
 	 */
 	private function combineFilter($filters, $operator) {
 		$combinedFilter = '('.$operator;
-		foreach($filters as $filter) {
+		foreach ($filters as $filter) {
 			if ($filter !== '' && $filter[0] !== '(') {
 				$filter = '('.$filter.')';
 			}
-			$combinedFilter.=$filter;
+			$combinedFilter .= $filter;
 		}
-		$combinedFilter.=')';
+		$combinedFilter .= ')';
 		return $combinedFilter;
 	}
 
@@ -1352,17 +1352,17 @@ 
 	 * @throws \Exception
 	 */
 	private function getAdvancedFilterPartForSearch($search, $searchAttributes) {
-		if(!is_array($searchAttributes) || count($searchAttributes) < 2) {
+		if (!is_array($searchAttributes) || count($searchAttributes) < 2) {
 			throw new \Exception('searchAttributes must be an array with at least two string');
 		}
 		$searchWords = explode(' ', trim($search));
 		$wordFilters = array();
-		foreach($searchWords as $word) {
+		foreach ($searchWords as $word) {
 			$word = $this->prepareSearchTerm($word);
 			//every word needs to appear at least once
 			$wordMatchOneAttrFilters = array();
-			foreach($searchAttributes as $attr) {
-				$wordMatchOneAttrFilters[] = $attr . '=' . $word;
+			foreach ($searchAttributes as $attr) {
+				$wordMatchOneAttrFilters[] = $attr.'='.$word;
 			}
 			$wordFilters[] = $this->combineFilterWithOr($wordMatchOneAttrFilters);
 		}
@@ -1380,10 +1380,10 @@ 
 	private function getFilterPartForSearch($search, $searchAttributes, $fallbackAttribute) {
 		$filter = array();
 		$haveMultiSearchAttributes = (is_array($searchAttributes) && count($searchAttributes) > 0);
-		if($haveMultiSearchAttributes && strpos(trim($search), ' ') !== false) {
+		if ($haveMultiSearchAttributes && strpos(trim($search), ' ') !== false) {
 			try {
 				return $this->getAdvancedFilterPartForSearch($search, $searchAttributes);
-			} catch(\Exception $e) {
+			} catch (\Exception $e) {
 				\OCP\Util::writeLog(
 					'user_ldap',
 					'Creating advanced filter for search failed, falling back to simple method.',
@@ -1393,17 +1393,17 @@ 
 		}
 
 		$search = $this->prepareSearchTerm($search);
-		if(!is_array($searchAttributes) || count($searchAttributes) === 0) {
+		if (!is_array($searchAttributes) || count($searchAttributes) === 0) {
 			if ($fallbackAttribute === '') {
 				return '';
 			}
-			$filter[] = $fallbackAttribute . '=' . $search;
+			$filter[] = $fallbackAttribute.'='.$search;
 		} else {
-			foreach($searchAttributes as $attribute) {
-				$filter[] = $attribute . '=' . $search;
+			foreach ($searchAttributes as $attribute) {
+				$filter[] = $attribute.'='.$search;
 			}
 		}
-		if(count($filter) === 1) {
+		if (count($filter) === 1) {
 			return '('.$filter[0].')';
 		}
 		return $this->combineFilterWithOr($filter);
@@ -1424,7 +1424,7 @@ 
 		if ($term === '') {
 			$result = '*';
 		} else if ($allowEnum !== 'no') {
-			$result = $term . '*';
+			$result = $term.'*';
 		}
 		return $result;
 	}
@@ -1436,7 +1436,7 @@ 
 	public function getFilterForUserCount() {
 		$filter = $this->combineFilterWithAnd(array(
 			$this->connection->ldapUserFilter,
-			$this->connection->ldapUserDisplayName . '=*'
+			$this->connection->ldapUserDisplayName.'=*'
 		));
 
 		return $filter;
@@ -1454,7 +1454,7 @@ 
 			'ldapAgentName' => $name,
 			'ldapAgentPassword' => $password
 		);
-		if(!$testConnection->setConfiguration($credentials)) {
+		if (!$testConnection->setConfiguration($credentials)) {
 			return false;
 		}
 		return $testConnection->bind();
@@ -1476,30 +1476,30 @@ 
 			// Sacrebleu! The UUID attribute is unknown :( We need first an
 			// existing DN to be able to reliably detect it.
 			$result = $this->search($filter, $base, ['dn'], 1);
-			if(!isset($result[0]) || !isset($result[0]['dn'])) {
+			if (!isset($result[0]) || !isset($result[0]['dn'])) {
 				throw new \Exception('Cannot determine UUID attribute');
 			}
 			$dn = $result[0]['dn'][0];
-			if(!$this->detectUuidAttribute($dn, true)) {
+			if (!$this->detectUuidAttribute($dn, true)) {
 				throw new \Exception('Cannot determine UUID attribute');
 			}
 		} else {
 			// The UUID attribute is either known or an override is given.
 			// By calling this method we ensure that $this->connection->$uuidAttr
 			// is definitely set
-			if(!$this->detectUuidAttribute('', true)) {
+			if (!$this->detectUuidAttribute('', true)) {
 				throw new \Exception('Cannot determine UUID attribute');
 			}
 		}
 
 		$uuidAttr = $this->connection->ldapUuidUserAttribute;
-		if($uuidAttr === 'guid' || $uuidAttr === 'objectguid') {
+		if ($uuidAttr === 'guid' || $uuidAttr === 'objectguid') {
 			$uuid = $this->formatGuid2ForFilterUser($uuid);
 		}
 
-		$filter = $uuidAttr . '=' . $uuid;
+		$filter = $uuidAttr.'='.$uuid;
 		$result = $this->searchUsers($filter, ['dn'], 2);
-		if(is_array($result) && isset($result[0]) && isset($result[0]['dn']) && count($result) === 1) {
+		if (is_array($result) && isset($result[0]) && isset($result[0]['dn']) && count($result) === 1) {
 			// we put the count into account to make sure that this is
 			// really unique
 			return $result[0]['dn'][0];
@@ -1516,7 +1516,7 @@ 
 	 * @return bool true on success, false otherwise
 	 */
 	private function detectUuidAttribute($dn, $isUser = true, $force = false) {
-		if($isUser) {
+		if ($isUser) {
 			$uuidAttr     = 'ldapUuidUserAttribute';
 			$uuidOverride = $this->connection->ldapExpertUUIDUserAttr;
 		} else {
@@ -1524,7 +1524,7 @@ 
 			$uuidOverride = $this->connection->ldapExpertUUIDGroupAttr;
 		}
 
-		if(($this->connection->$uuidAttr !== 'auto') && !$force) {
+		if (($this->connection->$uuidAttr !== 'auto') && !$force) {
 			return true;
 		}
 
@@ -1536,9 +1536,9 @@ 
 		// for now, supported attributes are entryUUID, nsuniqueid, objectGUID, ipaUniqueID
 		$testAttributes = array('entryuuid', 'nsuniqueid', 'objectguid', 'guid', 'ipauniqueid');
 
-		foreach($testAttributes as $attribute) {
+		foreach ($testAttributes as $attribute) {
 			$value = $this->readAttribute($dn, $attribute);
-			if(is_array($value) && isset($value[0]) && !empty($value[0])) {
+			if (is_array($value) && isset($value[0]) && !empty($value[0])) {
 				\OCP\Util::writeLog('user_ldap',
 									'Setting '.$attribute.' as '.$uuidAttr,
 									\OCP\Util::DEBUG);
@@ -1559,7 +1559,7 @@ 
 	 * @return string|bool
 	 */
 	public function getUUID($dn, $isUser = true) {
-		if($isUser) {
+		if ($isUser) {
 			$uuidAttr     = 'ldapUuidUserAttribute';
 			$uuidOverride = $this->connection->ldapExpertUUIDUserAttr;
 		} else {
@@ -1568,15 +1568,15 @@ 
 		}
 
 		$uuid = false;
-		if($this->detectUuidAttribute($dn, $isUser)) {
+		if ($this->detectUuidAttribute($dn, $isUser)) {
 			$uuid = $this->readAttribute($dn, $this->connection->$uuidAttr);
-			if( !is_array($uuid)
+			if (!is_array($uuid)
 				&& $uuidOverride !== ''
 				&& $this->detectUuidAttribute($dn, $isUser, true)) {
 					$uuid = $this->readAttribute($dn,
 												 $this->connection->$uuidAttr);
 			}
-			if(is_array($uuid) && isset($uuid[0]) && !empty($uuid[0])) {
+			if (is_array($uuid) && isset($uuid[0]) && !empty($uuid[0])) {
 				$uuid = $uuid[0];
 			}
 		}
@@ -1593,19 +1593,19 @@ 
 	private function convertObjectGUID2Str($oguid) {
 		$hex_guid = bin2hex($oguid);
 		$hex_guid_to_guid_str = '';
-		for($k = 1; $k <= 4; ++$k) {
+		for ($k = 1; $k <= 4; ++$k) {
 			$hex_guid_to_guid_str .= substr($hex_guid, 8 - 2 * $k, 2);
 		}
 		$hex_guid_to_guid_str .= '-';
-		for($k = 1; $k <= 2; ++$k) {
+		for ($k = 1; $k <= 2; ++$k) {
 			$hex_guid_to_guid_str .= substr($hex_guid, 12 - 2 * $k, 2);
 		}
 		$hex_guid_to_guid_str .= '-';
-		for($k = 1; $k <= 2; ++$k) {
+		for ($k = 1; $k <= 2; ++$k) {
 			$hex_guid_to_guid_str .= substr($hex_guid, 16 - 2 * $k, 2);
 		}
-		$hex_guid_to_guid_str .= '-' . substr($hex_guid, 16, 4);
-		$hex_guid_to_guid_str .= '-' . substr($hex_guid, 20);
+		$hex_guid_to_guid_str .= '-'.substr($hex_guid, 16, 4);
+		$hex_guid_to_guid_str .= '-'.substr($hex_guid, 20);
 
 		return strtoupper($hex_guid_to_guid_str);
 	}
@@ -1622,11 +1622,11 @@ 
 	 * @return string
 	 */
 	public function formatGuid2ForFilterUser($guid) {
-		if(!is_string($guid)) {
+		if (!is_string($guid)) {
 			throw new \InvalidArgumentException('String expected');
 		}
 		$blocks = explode('-', $guid);
-		if(count($blocks) !== 5) {
+		if (count($blocks) !== 5) {
 			/*
 			 * Why not throw an Exception instead? This method is a utility
 			 * called only when trying to figure out whether a "missing" known
@@ -1639,20 +1639,20 @@ 
 			 * user. Instead we write a log message.
 			 */
 			\OC::$server->getLogger()->info(
-				'Passed string does not resemble a valid GUID. Known UUID ' .
+				'Passed string does not resemble a valid GUID. Known UUID '.
 				'({uuid}) probably does not match UUID configuration.',
-				[ 'app' => 'user_ldap', 'uuid' => $guid ]
+				['app' => 'user_ldap', 'uuid' => $guid]
 			);
 			return $guid;
 		}
-		for($i=0; $i < 3; $i++) {
+		for ($i = 0; $i < 3; $i++) {
 			$pairs = str_split($blocks[$i], 2);
 			$pairs = array_reverse($pairs);
 			$blocks[$i] = implode('', $pairs);
 		}
-		for($i=0; $i < 5; $i++) {
+		for ($i = 0; $i < 5; $i++) {
 			$pairs = str_split($blocks[$i], 2);
-			$blocks[$i] = '\\' . implode('\\', $pairs);
+			$blocks[$i] = '\\'.implode('\\', $pairs);
 		}
 		return implode('', $blocks);
 	}
@@ -1666,12 +1666,12 @@ 
 		$domainDN = $this->getDomainDNFromDN($dn);
 		$cacheKey = 'getSID-'.$domainDN;
 		$sid = $this->connection->getFromCache($cacheKey);
-		if(!is_null($sid)) {
+		if (!is_null($sid)) {
 			return $sid;
 		}
 
 		$objectSid = $this->readAttribute($domainDN, 'objectsid');
-		if(!is_array($objectSid) || empty($objectSid)) {
+		if (!is_array($objectSid) || empty($objectSid)) {
 			$this->connection->writeToCache($cacheKey, false);
 			return false;
 		}
@@ -1729,12 +1729,12 @@ 
 		$belongsToBase = false;
 		$bases = $this->helper->sanitizeDN($bases);
 
-		foreach($bases as $base) {
+		foreach ($bases as $base) {
 			$belongsToBase = true;
-			if(mb_strripos($dn, $base, 0, 'UTF-8') !== (mb_strlen($dn, 'UTF-8')-mb_strlen($base, 'UTF-8'))) {
+			if (mb_strripos($dn, $base, 0, 'UTF-8') !== (mb_strlen($dn, 'UTF-8') - mb_strlen($base, 'UTF-8'))) {
 				$belongsToBase = false;
 			}
-			if($belongsToBase) {
+			if ($belongsToBase) {
 				break;
 			}
 		}
@@ -1745,7 +1745,7 @@ 
 	 * resets a running Paged Search operation
 	 */
 	private function abandonPagedSearch() {
-		if($this->connection->hasPagedResultSupport) {
+		if ($this->connection->hasPagedResultSupport) {
 			$cr = $this->connection->getConnectionResource();
 			$this->invokeLDAPMethod('controlPagedResult', $cr, 0, false, $this->lastCookie);
 			$this->getPagedSearchResultState();
@@ -1763,16 +1763,16 @@ 
 	 * @return string containing the key or empty if none is cached
 	 */
 	private function getPagedResultCookie($base, $filter, $limit, $offset) {
-		if($offset === 0) {
+		if ($offset === 0) {
 			return '';
 		}
 		$offset -= $limit;
 		//we work with cache here
-		$cacheKey = 'lc' . crc32($base) . '-' . crc32($filter) . '-' . intval($limit) . '-' . intval($offset);
+		$cacheKey = 'lc'.crc32($base).'-'.crc32($filter).'-'.intval($limit).'-'.intval($offset);
 		$cookie = '';
-		if(isset($this->cookies[$cacheKey])) {
+		if (isset($this->cookies[$cacheKey])) {
 			$cookie = $this->cookies[$cacheKey];
-			if(is_null($cookie)) {
+			if (is_null($cookie)) {
 				$cookie = '';
 			}
 		}
@@ -1790,11 +1790,11 @@ 
 	 * @return bool
 	 */
 	public function hasMoreResults() {
-		if(!$this->connection->hasPagedResultSupport) {
+		if (!$this->connection->hasPagedResultSupport) {
 			return false;
 		}
 
-		if(empty($this->lastCookie) && $this->lastCookie !== '0') {
+		if (empty($this->lastCookie) && $this->lastCookie !== '0') {
 			// as in RFC 2696, when all results are returned, the cookie will
 			// be empty.
 			return false;
@@ -1814,8 +1814,8 @@ 
 	 */
 	private function setPagedResultCookie($base, $filter, $limit, $offset, $cookie) {
 		// allow '0' for 389ds
-		if(!empty($cookie) || $cookie === '0') {
-			$cacheKey = 'lc' . crc32($base) . '-' . crc32($filter) . '-' .intval($limit) . '-' . intval($offset);
+		if (!empty($cookie) || $cookie === '0') {
+			$cacheKey = 'lc'.crc32($base).'-'.crc32($filter).'-'.intval($limit).'-'.intval($offset);
 			$this->cookies[$cacheKey] = $cookie;
 			$this->lastCookie = $cookie;
 		}
@@ -1842,17 +1842,17 @@ 
 	 */
 	private function initPagedSearch($filter, $bases, $attr, $limit, $offset) {
 		$pagedSearchOK = false;
-		if($this->connection->hasPagedResultSupport && ($limit !== 0)) {
+		if ($this->connection->hasPagedResultSupport && ($limit !== 0)) {
 			$offset = intval($offset); //can be null
 			\OCP\Util::writeLog('user_ldap',
 				'initializing paged search for  Filter '.$filter.' base '.print_r($bases, true)
-				.' attr '.print_r($attr, true). ' limit ' .$limit.' offset '.$offset,
+				.' attr '.print_r($attr, true).' limit '.$limit.' offset '.$offset,
 				\OCP\Util::DEBUG);
 			//get the cookie from the search for the previous search, required by LDAP
-			foreach($bases as $base) {
+			foreach ($bases as $base) {
 
 				$cookie = $this->getPagedResultCookie($base, $filter, $limit, $offset);
-				if(empty($cookie) && $cookie !== "0" && ($offset > 0)) {
+				if (empty($cookie) && $cookie !== "0" && ($offset > 0)) {
 					// no cookie known, although the offset is not 0. Maybe cache run out. We need
 					// to start all over *sigh* (btw, Dear Reader, did you know LDAP paged
 					// searching was designed by MSFT?)
@@ -1865,18 +1865,18 @@ 
 					$cookie = $this->getPagedResultCookie($base, $filter, $limit, $offset);
 					//still no cookie? obviously, the server does not like us. Let's skip paging efforts.
 					//TODO: remember this, probably does not change in the next request...
-					if(empty($cookie) && $cookie !== '0') {
+					if (empty($cookie) && $cookie !== '0') {
 						// '0' is valid, because 389ds
 						$cookie = null;
 					}
 				}
-				if(!is_null($cookie)) {
+				if (!is_null($cookie)) {
 					//since offset = 0, this is a new search. We abandon other searches that might be ongoing.
 					$this->abandonPagedSearch();
 					$pagedSearchOK = $this->invokeLDAPMethod('controlPagedResult',
 						$this->connection->getConnectionResource(), $limit,
 						false, $cookie);
-					if(!$pagedSearchOK) {
+					if (!$pagedSearchOK) {
 						return false;
 					}
 					\OCP\Util::writeLog('user_ldap', 'Ready for a paged search', \OCP\Util::DEBUG);
@@ -1893,7 +1893,7 @@ 
 		 * So we added "&& !empty($this->lastCookie)" to this test to ignore pagination
 		 * if we don't have a previous paged search.
 		 */
-		} else if($this->connection->hasPagedResultSupport && $limit === 0 && !empty($this->lastCookie)) {
+		} else if ($this->connection->hasPagedResultSupport && $limit === 0 && !empty($this->lastCookie)) {
 			// a search without limit was requested. However, if we do use
 			// Paged Search once, we always must do it. This requires us to
 			// initialize it with the configured page size.