nextcloud / server

apps/user_ldap/lib/Group_LDAP.php

Indentation +1140 added lines, -1140 removed lines

@@ -46,1145 +46,1145 @@
 use OCP\ILogger;
 
 class Group_LDAP extends BackendUtility implements \OCP\GroupInterface, IGroupLDAP {
-	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;
-
-	/** @var GroupPluginManager */
-	protected $groupPluginManager;
-
-	public function __construct(Access $access, GroupPluginManager $groupPluginManager) {
-		parent::__construct($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();
-		$this->groupPluginManager = $groupPluginManager;
-	}
-
-	/**
-	 * 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, ILogger::DEBUG);
-			}
-		}
-		return $dynamicMembers;
-	}
-
-	/**
-	 * @param string $dnGroup
-	 * @param array|null &$seen
-	 * @return array|mixed|null
-	 * @throws \OC\ServerNotAvailableException
-	 */
-	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($groupMembers !== null) {
-			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 $member) {
-				$allMembers[$member] = 1;
-				$nestedGroups = $this->access->connection->ldapNestedGroups;
-				if (!empty($nestedGroups)) {
-					$subMembers = $this->_groupMembers($member, $seen);
-					if ($subMembers) {
-						$allMembers += $subMembers;
-					}
-				}
-			}
-		}
-
-		$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 = $this->access->connection->ldapNestedGroups;
-		if ((int)$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;
-
-		return $this->access->combineFilterWithAnd($filterParts);
-	}
-
-	/**
-	 * 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;
-
-		return $this->access->combineFilterWithAnd($filterParts);
-	}
-
-	/**
-	 * 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), ILogger::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((int)$this->access->connection->hasMemberOfFilterSupport === 1
-			&& (int)$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, ILogger::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 = $this->access->combineFilterWithAnd(array(
-					str_replace('%uid', trim($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, $search = '') {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::COUNT_USERS)) {
-			return $this->groupPluginManager->countUsersInGroup($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, ILogger::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, ILogger::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);
-		$pagingSize = (int)$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.')', ILogger::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 $actions bitwise-or'ed actions
-	* @return boolean
-	*
-	* Returns the supported actions as int to be
-	* compared with GroupInterface::CREATE_GROUP etc.
-	*/
-	public function implementsActions($actions) {
-		return (bool)((GroupInterface::COUNT_USERS |
-				$this->groupPluginManager->getImplementedActions()) & $actions);
-	}
-
-	/**
-	 * Return access for LDAP interaction.
-	 * @return Access instance of Access for LDAP interaction
-	 */
-	public function getLDAPAccess($gid) {
-		return $this->access;
-	}
-
-	/**
-	 * create a group
-	 * @param string $gid
-	 * @return bool
-	 * @throws \Exception
-	 */
-	public function createGroup($gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::CREATE_GROUP)) {
-			if ($dn = $this->groupPluginManager->createGroup($gid)) {
-				//updates group mapping
-				$this->access->dn2ocname($dn, $gid, false);
-				$this->access->connection->writeToCache("groupExists".$gid, true);
-			}
-			return $dn != null;
-		}
-		throw new \Exception('Could not create group in LDAP backend.');
-	}
-
-	/**
-	 * delete a group
-	 * @param string $gid gid of the group to delete
-	 * @return bool
-	 * @throws \Exception
-	 */
-	public function deleteGroup($gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::DELETE_GROUP)) {
-			if ($ret = $this->groupPluginManager->deleteGroup($gid)) {
-				#delete group in nextcloud internal db
-				$this->access->getGroupMapper()->unmap($gid);
-				$this->access->connection->writeToCache("groupExists".$gid, false);
-			}
-			return $ret;
-		}
-		throw new \Exception('Could not delete group in LDAP backend.');
-	}
-
-	/**
-	 * Add a user to a group
-	 * @param string $uid Name of the user to add to group
-	 * @param string $gid Name of the group in which add the user
-	 * @return bool
-	 * @throws \Exception
-	 */
-	public function addToGroup($uid, $gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::ADD_TO_GROUP)) {
-			if ($ret = $this->groupPluginManager->addToGroup($uid, $gid)) {
-				$this->access->connection->clearCache();
-			}
-			return $ret;
-		}
-		throw new \Exception('Could not add user to group in LDAP backend.');
-	}
-
-	/**
-	 * Removes a user from a group
-	 * @param string $uid Name of the user to remove from group
-	 * @param string $gid Name of the group from which remove the user
-	 * @return bool
-	 * @throws \Exception
-	 */
-	public function removeFromGroup($uid, $gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::REMOVE_FROM_GROUP)) {
-			if ($ret = $this->groupPluginManager->removeFromGroup($uid, $gid)) {
-				$this->access->connection->clearCache();
-			}
-			return $ret;
-		}
-		throw new \Exception('Could not remove user from group in LDAP backend.');
-	}
-
-	/**
-	 * Gets group details
-	 * @param string $gid Name of the group
-	 * @return array | false
-	 * @throws \Exception
-	 */
-	public function getGroupDetails($gid) {
-		if ($this->groupPluginManager->implementsActions(GroupInterface::GROUP_DETAILS)) {
-			return $this->groupPluginManager->getGroupDetails($gid);
-		}
-		throw new \Exception('Could not get group details in LDAP backend.');
-	}
-
-	/**
-	 * Return LDAP connection resource from a cloned connection.
-	 * The cloned connection needs to be closed manually.
-	 * of the current access.
-	 * @param string $gid
-	 * @return resource of the LDAP connection
-	 */
-	public function getNewLDAPConnection($gid) {
-		$connection = clone $this->access->getConnection();
-		return $connection->getConnectionResource();
-	}
+    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;
+
+    /** @var GroupPluginManager */
+    protected $groupPluginManager;
+
+    public function __construct(Access $access, GroupPluginManager $groupPluginManager) {
+        parent::__construct($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();
+        $this->groupPluginManager = $groupPluginManager;
+    }
+
+    /**
+     * 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, ILogger::DEBUG);
+            }
+        }
+        return $dynamicMembers;
+    }
+
+    /**
+     * @param string $dnGroup
+     * @param array|null &$seen
+     * @return array|mixed|null
+     * @throws \OC\ServerNotAvailableException
+     */
+    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($groupMembers !== null) {
+            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 $member) {
+                $allMembers[$member] = 1;
+                $nestedGroups = $this->access->connection->ldapNestedGroups;
+                if (!empty($nestedGroups)) {
+                    $subMembers = $this->_groupMembers($member, $seen);
+                    if ($subMembers) {
+                        $allMembers += $subMembers;
+                    }
+                }
+            }
+        }
+
+        $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 = $this->access->connection->ldapNestedGroups;
+        if ((int)$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;
+
+        return $this->access->combineFilterWithAnd($filterParts);
+    }
+
+    /**
+     * 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;
+
+        return $this->access->combineFilterWithAnd($filterParts);
+    }
+
+    /**
+     * 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), ILogger::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((int)$this->access->connection->hasMemberOfFilterSupport === 1
+            && (int)$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, ILogger::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 = $this->access->combineFilterWithAnd(array(
+                    str_replace('%uid', trim($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, $search = '') {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::COUNT_USERS)) {
+            return $this->groupPluginManager->countUsersInGroup($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, ILogger::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, ILogger::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);
+        $pagingSize = (int)$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.')', ILogger::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 $actions bitwise-or'ed actions
+     * @return boolean
+     *
+     * Returns the supported actions as int to be
+     * compared with GroupInterface::CREATE_GROUP etc.
+     */
+    public function implementsActions($actions) {
+        return (bool)((GroupInterface::COUNT_USERS |
+                $this->groupPluginManager->getImplementedActions()) & $actions);
+    }
+
+    /**
+     * Return access for LDAP interaction.
+     * @return Access instance of Access for LDAP interaction
+     */
+    public function getLDAPAccess($gid) {
+        return $this->access;
+    }
+
+    /**
+     * create a group
+     * @param string $gid
+     * @return bool
+     * @throws \Exception
+     */
+    public function createGroup($gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::CREATE_GROUP)) {
+            if ($dn = $this->groupPluginManager->createGroup($gid)) {
+                //updates group mapping
+                $this->access->dn2ocname($dn, $gid, false);
+                $this->access->connection->writeToCache("groupExists".$gid, true);
+            }
+            return $dn != null;
+        }
+        throw new \Exception('Could not create group in LDAP backend.');
+    }
+
+    /**
+     * delete a group
+     * @param string $gid gid of the group to delete
+     * @return bool
+     * @throws \Exception
+     */
+    public function deleteGroup($gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::DELETE_GROUP)) {
+            if ($ret = $this->groupPluginManager->deleteGroup($gid)) {
+                #delete group in nextcloud internal db
+                $this->access->getGroupMapper()->unmap($gid);
+                $this->access->connection->writeToCache("groupExists".$gid, false);
+            }
+            return $ret;
+        }
+        throw new \Exception('Could not delete group in LDAP backend.');
+    }
+
+    /**
+     * Add a user to a group
+     * @param string $uid Name of the user to add to group
+     * @param string $gid Name of the group in which add the user
+     * @return bool
+     * @throws \Exception
+     */
+    public function addToGroup($uid, $gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::ADD_TO_GROUP)) {
+            if ($ret = $this->groupPluginManager->addToGroup($uid, $gid)) {
+                $this->access->connection->clearCache();
+            }
+            return $ret;
+        }
+        throw new \Exception('Could not add user to group in LDAP backend.');
+    }
+
+    /**
+     * Removes a user from a group
+     * @param string $uid Name of the user to remove from group
+     * @param string $gid Name of the group from which remove the user
+     * @return bool
+     * @throws \Exception
+     */
+    public function removeFromGroup($uid, $gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::REMOVE_FROM_GROUP)) {
+            if ($ret = $this->groupPluginManager->removeFromGroup($uid, $gid)) {
+                $this->access->connection->clearCache();
+            }
+            return $ret;
+        }
+        throw new \Exception('Could not remove user from group in LDAP backend.');
+    }
+
+    /**
+     * Gets group details
+     * @param string $gid Name of the group
+     * @return array | false
+     * @throws \Exception
+     */
+    public function getGroupDetails($gid) {
+        if ($this->groupPluginManager->implementsActions(GroupInterface::GROUP_DETAILS)) {
+            return $this->groupPluginManager->getGroupDetails($gid);
+        }
+        throw new \Exception('Could not get group details in LDAP backend.');
+    }
+
+    /**
+     * Return LDAP connection resource from a cloned connection.
+     * The cloned connection needs to be closed manually.
+     * of the current access.
+     * @param string $gid
+     * @return resource of the LDAP connection
+     */
+    public function getNewLDAPConnection($gid) {
+        $connection = clone $this->access->getConnection();
+        return $connection->getConnectionResource();
+    }
 
 }

Spacing +94 added lines, -94 removed lines

@@ -65,7 +65,7 @@ 
 		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;
 		}
 
@@ -83,25 +83,25 @@ 
 	 * 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);
@@ -110,13 +110,13 @@ 
 
 		$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;
 		}
@@ -124,21 +124,21 @@ 
 		//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);
@@ -148,7 +148,7 @@ 
 					$dns = array_merge($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);
@@ -191,14 +191,14 @@ 
 			$pos = strpos($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 ' . $dnGroup, ILogger::DEBUG);
+					'of group '.$dnGroup, ILogger::DEBUG);
 			}
 		}
 		return $dynamicMembers;
@@ -222,7 +222,7 @@ 
 		// used extensively in cron job, caching makes sense for nested groups
 		$cacheKey = '_groupMembers'.$dnGroup;
 		$groupMembers = $this->access->connection->getFromCache($cacheKey);
-		if($groupMembers !== null) {
+		if ($groupMembers !== null) {
 			return $groupMembers;
 		}
 		$seen[$dnGroup] = 1;
@@ -266,9 +266,9 @@ 
 			return array();
 		}
 		$groups = $this->access->groupsMatchFilter($groups);
-		$allGroups =  $groups;
+		$allGroups = $groups;
 		$nestedGroups = $this->access->connection->ldapNestedGroups;
-		if ((int)$nestedGroups === 1) {
+		if ((int) $nestedGroups === 1) {
 			foreach ($groups as $group) {
 				$subGroups = $this->_getGroupDNsFromMemberOf($group, $seen);
 				$allGroups = array_merge($allGroups, $subGroups);
@@ -284,9 +284,9 @@ 
 	 * @return string|bool
 	 */
 	public function gidNumber2Name($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;
 		}
 
@@ -294,10 +294,10 @@ 
 		$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 = $result[0]['dn'][0];
@@ -320,7 +320,7 @@ 
 	 */
 	private function getEntryGidNumber($dn, $attribute) {
 		$value = $this->access->readAttribute($dn, $attribute);
-		if(is_array($value) && !empty($value)) {
+		if (is_array($value) && !empty($value)) {
 			return $value[0];
 		}
 		return false;
@@ -342,9 +342,9 @@ 
 	 */
 	public function getUserGidNumber($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) {
 				$this->access->connection->hasGidNumber = false;
 			}
 		}
@@ -361,7 +361,7 @@ 
 	 */
 	private function prepareFilterForUsersHasGidNumber($groupDN, $search = '') {
 		$groupID = $this->getGroupGidNumber($groupDN);
-		if($groupID === false) {
+		if ($groupID === false) {
 			throw new \Exception('Not a valid group');
 		}
 
@@ -370,7 +370,7 @@ 
 		if ($search !== '') {
 			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
 		}
-		$filterParts[] = $this->access->connection->ldapGidNumber .'=' . $groupID;
+		$filterParts[] = $this->access->connection->ldapGidNumber.'='.$groupID;
 
 		return $this->access->combineFilterWithAnd($filterParts);
 	}
@@ -412,7 +412,7 @@ 
 		try {
 			$filter = $this->prepareFilterForUsersHasGidNumber($groupDN, $search);
 			$users = $this->access->countUsers($filter, ['dn'], $limit, $offset);
-			return (int)$users;
+			return (int) $users;
 		} catch (\Exception $e) {
 			return 0;
 		}
@@ -425,9 +425,9 @@ 
 	 */
 	public function getUserGroupByGid($dn) {
 		$groupID = $this->getUserGidNumber($dn);
-		if($groupID !== false) {
+		if ($groupID !== false) {
 			$groupName = $this->gidNumber2Name($groupID, $dn);
-			if($groupName !== false) {
+			if ($groupName !== false) {
 				return $groupName;
 			}
 		}
@@ -444,22 +444,22 @@ 
 	public function primaryGroupID2Name($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 = $result[0]['dn'][0];
@@ -482,7 +482,7 @@ 
 	 */
 	private function getEntryGroupID($dn, $attribute) {
 		$value = $this->access->readAttribute($dn, $attribute);
-		if(is_array($value) && !empty($value)) {
+		if (is_array($value) && !empty($value)) {
 			return $value[0];
 		}
 		return false;
@@ -504,9 +504,9 @@ 
 	 */
 	public function getUserPrimaryGroupIDs($dn) {
 		$primaryGroupID = false;
-		if($this->access->connection->hasPrimaryGroups) {
+		if ($this->access->connection->hasPrimaryGroups) {
 			$primaryGroupID = $this->getEntryGroupID($dn, 'primaryGroupID');
-			if($primaryGroupID === false) {
+			if ($primaryGroupID === false) {
 				$this->access->connection->hasPrimaryGroups = false;
 			}
 		}
@@ -523,7 +523,7 @@ 
 	 */
 	private function prepareFilterForUsersInPrimaryGroup($groupDN, $search = '') {
 		$groupID = $this->getGroupPrimaryGroupID($groupDN);
-		if($groupID === false) {
+		if ($groupID === false) {
 			throw new \Exception('Not a valid group');
 		}
 
@@ -532,7 +532,7 @@ 
 		if ($search !== '') {
 			$filterParts[] = $this->access->getFilterPartForUserSearch($search);
 		}
-		$filterParts[] = 'primaryGroupID=' . $groupID;
+		$filterParts[] = 'primaryGroupID='.$groupID;
 
 		return $this->access->combineFilterWithAnd($filterParts);
 	}
@@ -574,7 +574,7 @@ 
 		try {
 			$filter = $this->prepareFilterForUsersInPrimaryGroup($groupDN, $search);
 			$users = $this->access->countUsers($filter, array('dn'), $limit, $offset);
-			return (int)$users;
+			return (int) $users;
 		} catch (\Exception $e) {
 			return 0;
 		}
@@ -587,9 +587,9 @@ 
 	 */
 	public function getUserPrimaryGroup($dn) {
 		$groupID = $this->getUserPrimaryGroupIDs($dn);
-		if($groupID !== false) {
+		if ($groupID !== false) {
 			$groupName = $this->primaryGroupID2Name($groupID, $dn);
-			if($groupName !== false) {
+			if ($groupName !== false) {
 				return $groupName;
 			}
 		}
@@ -608,16 +608,16 @@ 
 	 * This function includes groups based on dynamic group membership.
 	 */
 	public function getUserGroups($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();
 		}
@@ -631,14 +631,14 @@ 
 		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 = $this->access->readAttribute(
@@ -649,7 +649,7 @@ 
 					if ($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[] = $groupName;
@@ -657,7 +657,7 @@ 
 					}
 				} else {
 					\OCP\Util::writeLog('user_ldap', 'No search filter found on member url '.
-						'of group ' . print_r($dynamicGroup, true), ILogger::DEBUG);
+						'of group '.print_r($dynamicGroup, true), ILogger::DEBUG);
 				}
 			}
 		}
@@ -665,15 +665,15 @@ 
 		// if possible, read out membership via memberOf. It's far faster than
 		// performing a search, which still is a fallback later.
 		// memberof doesn't support memberuid, so skip it here.
-		if((int)$this->access->connection->hasMemberOfFilterSupport === 1
-			&& (int)$this->access->connection->useMemberOfToDetectMembership === 1
+		if ((int) $this->access->connection->hasMemberOfFilterSupport === 1
+			&& (int) $this->access->connection->useMemberOfToDetectMembership === 1
 		    && strtolower($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($groupName)) {
+					if (is_string($groupName)) {
 						// be sure to never return false if the dn could not be
 						// resolved to a name, for whatever reason.
 						$groups[] = $groupName;
@@ -681,10 +681,10 @@ 
 				}
 			}
 
-			if($primaryGroup !== false) {
+			if ($primaryGroup !== false) {
 				$groups[] = $primaryGroup;
 			}
-			if($gidGroupName !== false) {
+			if ($gidGroupName !== false) {
 				$groups[] = $gidGroupName;
 			}
 			$this->access->connection->writeToCache($cacheKey, $groups);
@@ -692,14 +692,14 @@ 
 		}
 
 		//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, ILogger::DEBUG);
 			}
 			$uid = $result[0];
@@ -708,7 +708,7 @@ 
 			$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));
@@ -717,10 +717,10 @@ 
 			$groups = array_merge($groups, $groupsByMember);
 		}
 
-		if($primaryGroup !== false) {
+		if ($primaryGroup !== false) {
 			$groups[] = $primaryGroup;
 		}
-		if($gidGroupName !== false) {
+		if ($gidGroupName !== false) {
 			$groups[] = $gidGroupName;
 		}
 
@@ -758,7 +758,7 @@ 
 				$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, $supergroups);
 					}
 				}
@@ -777,33 +777,33 @@ 
 	 * @return array with user ids
 	 */
 	public function usersInGroup($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();
@@ -812,7 +812,7 @@ 
 		$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 [];
@@ -821,29 +821,29 @@ 
 		$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 = $this->access->combineFilterWithAnd(array(
 					str_replace('%uid', trim($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;
 				}
 			}
@@ -871,16 +871,16 @@ 
 		}
 
 		$cacheKey = 'countUsersInGroup-'.$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;
@@ -888,7 +888,7 @@ 
 
 		$members = array_keys($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;
@@ -913,27 +913,27 @@ 
 		//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[] = $ocname;
 				}
 			}
@@ -956,7 +956,7 @@ 
 	 * Returns a list with all groups (used by getGroups)
 	 */
 	protected function getGroupsChunk($search = '', $limit = -1, $offset = 0) {
-		if(!$this->enabled) {
+		if (!$this->enabled) {
 			return array();
 		}
 		$cacheKey = 'getGroups-'.$search.'-'.$limit.'-'.$offset;
@@ -964,13 +964,13 @@ 
 		//Check cache before driving unnecessary searches
 		\OCP\Util::writeLog('user_ldap', 'getGroups '.$cacheKey, ILogger::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 = $this->access->combineFilterWithAnd(array(
@@ -1002,11 +1002,11 @@ 
 	 * (active directory has a limit of 1000 by default)
 	 */
 	public function getGroups($search = '', $limit = -1, $offset = 0) {
-		if(!$this->enabled) {
+		if (!$this->enabled) {
 			return array();
 		}
 		$search = $this->access->escapeFilterPart($search, true);
-		$pagingSize = (int)$this->access->connection->ldapPagingSize;
+		$pagingSize = (int) $this->access->connection->ldapPagingSize;
 		if (!$this->access->connection->hasPagedResultSupport || $pagingSize <= 0) {
 			return $this->getGroupsChunk($search, $limit, $offset);
 		}
@@ -1049,20 +1049,20 @@ 
 	 */
 	public function groupExists($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;
 		}
@@ -1080,7 +1080,7 @@ 
 	* compared with GroupInterface::CREATE_GROUP etc.
 	*/
 	public function implementsActions($actions) {
-		return (bool)((GroupInterface::COUNT_USERS |
+		return (bool) ((GroupInterface::COUNT_USERS |
 				$this->groupPluginManager->getImplementedActions()) & $actions);
 	}