nextcloud / server

lib/private/User/Manager.php

Indentation +436 added lines, -436 removed lines

@@ -54,440 +54,440 @@
  * @package OC\User
  */
 class Manager extends PublicEmitter implements IUserManager {
-	/**
-	 * @var \OCP\UserInterface[] $backends
-	 */
-	private $backends = array();
-
-	/**
-	 * @var \OC\User\User[] $cachedUsers
-	 */
-	private $cachedUsers = array();
-
-	/**
-	 * @var \OCP\IConfig $config
-	 */
-	private $config;
-
-	/**
-	 * @param \OCP\IConfig $config
-	 */
-	public function __construct(IConfig $config) {
-		$this->config = $config;
-		$cachedUsers = &$this->cachedUsers;
-		$this->listen('\OC\User', 'postDelete', function ($user) use (&$cachedUsers) {
-			/** @var \OC\User\User $user */
-			unset($cachedUsers[$user->getUID()]);
-		});
-	}
-
-	/**
-	 * Get the active backends
-	 * @return \OCP\UserInterface[]
-	 */
-	public function getBackends() {
-		return $this->backends;
-	}
-
-	/**
-	 * register a user backend
-	 *
-	 * @param \OCP\UserInterface $backend
-	 */
-	public function registerBackend($backend) {
-		$this->backends[] = $backend;
-	}
-
-	/**
-	 * remove a user backend
-	 *
-	 * @param \OCP\UserInterface $backend
-	 */
-	public function removeBackend($backend) {
-		$this->cachedUsers = array();
-		if (($i = array_search($backend, $this->backends)) !== false) {
-			unset($this->backends[$i]);
-		}
-	}
-
-	/**
-	 * remove all user backends
-	 */
-	public function clearBackends() {
-		$this->cachedUsers = array();
-		$this->backends = array();
-	}
-
-	/**
-	 * get a user by user id
-	 *
-	 * @param string $uid
-	 * @return \OC\User\User|null Either the user or null if the specified user does not exist
-	 */
-	public function get($uid) {
-		if (isset($this->cachedUsers[$uid])) { //check the cache first to prevent having to loop over the backends
-			return $this->cachedUsers[$uid];
-		}
-		foreach ($this->backends as $backend) {
-			if ($backend->userExists($uid)) {
-				return $this->getUserObject($uid, $backend);
-			}
-		}
-		return null;
-	}
-
-	/**
-	 * get or construct the user object
-	 *
-	 * @param string $uid
-	 * @param \OCP\UserInterface $backend
-	 * @param bool $cacheUser If false the newly created user object will not be cached
-	 * @return \OC\User\User
-	 */
-	protected function getUserObject($uid, $backend, $cacheUser = true) {
-		if (isset($this->cachedUsers[$uid])) {
-			return $this->cachedUsers[$uid];
-		}
-
-		if (method_exists($backend, 'loginName2UserName')) {
-			$loginName = $backend->loginName2UserName($uid);
-			if ($loginName !== false) {
-				$uid = $loginName;
-			}
-			if (isset($this->cachedUsers[$uid])) {
-				return $this->cachedUsers[$uid];
-			}
-		}
-
-		$user = new User($uid, $backend, $this, $this->config);
-		if ($cacheUser) {
-			$this->cachedUsers[$uid] = $user;
-		}
-		return $user;
-	}
-
-	/**
-	 * check if a user exists
-	 *
-	 * @param string $uid
-	 * @return bool
-	 */
-	public function userExists($uid) {
-		$user = $this->get($uid);
-		return ($user !== null);
-	}
-
-	/**
-	 * Check if the password is valid for the user
-	 *
-	 * @param string $loginName
-	 * @param string $password
-	 * @return mixed the User object on success, false otherwise
-	 */
-	public function checkPassword($loginName, $password) {
-		$result = $this->checkPasswordNoLogging($loginName, $password);
-
-		if ($result === false) {
-			\OC::$server->getLogger()->warning('Login failed: \''. $loginName .'\' (Remote IP: \''. \OC::$server->getRequest()->getRemoteAddress(). '\')', ['app' => 'core']);
-		}
-
-		return $result;
-	}
-
-	/**
-	 * Check if the password is valid for the user
-	 *
-	 * @internal
-	 * @param string $loginName
-	 * @param string $password
-	 * @return mixed the User object on success, false otherwise
-	 */
-	public function checkPasswordNoLogging($loginName, $password) {
-		$loginName = str_replace("\0", '', $loginName);
-		$password = str_replace("\0", '', $password);
-
-		foreach ($this->backends as $backend) {
-			if ($backend->implementsActions(Backend::CHECK_PASSWORD)) {
-				$uid = $backend->checkPassword($loginName, $password);
-				if ($uid !== false) {
-					return $this->getUserObject($uid, $backend);
-				}
-			}
-		}
-
-		return false;
-	}
-
-	/**
-	 * search by user id
-	 *
-	 * @param string $pattern
-	 * @param int $limit
-	 * @param int $offset
-	 * @return \OC\User\User[]
-	 */
-	public function search($pattern, $limit = null, $offset = null) {
-		$users = array();
-		foreach ($this->backends as $backend) {
-			$backendUsers = $backend->getUsers($pattern, $limit, $offset);
-			if (is_array($backendUsers)) {
-				foreach ($backendUsers as $uid) {
-					$users[$uid] = $this->getUserObject($uid, $backend);
-				}
-			}
-		}
-
-		uasort($users, function ($a, $b) {
-			/**
-			 * @var \OC\User\User $a
-			 * @var \OC\User\User $b
-			 */
-			return strcmp($a->getUID(), $b->getUID());
-		});
-		return $users;
-	}
-
-	/**
-	 * search by displayName
-	 *
-	 * @param string $pattern
-	 * @param int $limit
-	 * @param int $offset
-	 * @return \OC\User\User[]
-	 */
-	public function searchDisplayName($pattern, $limit = null, $offset = null) {
-		$users = array();
-		foreach ($this->backends as $backend) {
-			$backendUsers = $backend->getDisplayNames($pattern, $limit, $offset);
-			if (is_array($backendUsers)) {
-				foreach ($backendUsers as $uid => $displayName) {
-					$users[] = $this->getUserObject($uid, $backend);
-				}
-			}
-		}
-
-		usort($users, function ($a, $b) {
-			/**
-			 * @var \OC\User\User $a
-			 * @var \OC\User\User $b
-			 */
-			return strcmp(strtolower($a->getDisplayName()), strtolower($b->getDisplayName()));
-		});
-		return $users;
-	}
-
-	/**
-	 * @param string $uid
-	 * @param string $password
-	 * @throws \Exception
-	 * @return bool|\OC\User\User the created user or false
-	 */
-	public function createUser($uid, $password) {
-		$l = \OC::$server->getL10N('lib');
-		// Check the name for bad characters
-		// Allowed are: "a-z", "A-Z", "0-9" and "_.@-'"
-		if (preg_match('/[^a-zA-Z0-9 _\.@\-\']/', $uid)) {
-			throw new \Exception($l->t('Only the following characters are allowed in a username:'
-				. ' "a-z", "A-Z", "0-9", and "_.@-\'"'));
-		}
-		// No empty username
-		if (trim($uid) == '') {
-			throw new \Exception($l->t('A valid username must be provided'));
-		}
-		// No whitespace at the beginning or at the end
-		if (trim($uid) !== $uid) {
-			throw new \Exception($l->t('Username contains whitespace at the beginning or at the end'));
-		}
-		// Username only consists of 1 or 2 dots (directory traversal)
-		if (preg_match('/^\.{1,2}$/', $uid)) {
-			throw new \Exception($l->t('Username must not consist of dots only'));
-		}
-		// No empty password
-		if (trim($password) == '') {
-			throw new \Exception($l->t('A valid password must be provided'));
-		}
-
-		// Check if user already exists
-		if ($this->userExists($uid)) {
-			throw new \Exception($l->t('The username is already being used'));
-		}
-
-		$this->emit('\OC\User', 'preCreateUser', array($uid, $password));
-		foreach ($this->backends as $backend) {
-			if ($backend->implementsActions(Backend::CREATE_USER)) {
-				$backend->createUser($uid, $password);
-				$user = $this->getUserObject($uid, $backend);
-				$this->emit('\OC\User', 'postCreateUser', array($user, $password));
-				return $user;
-			}
-		}
-		return false;
-	}
-
-	/**
-	 * returns how many users per backend exist (if supported by backend)
-	 *
-	 * @param boolean $hasLoggedIn when true only users that have a lastLogin
-	 *                entry in the preferences table will be affected
-	 * @return array|int an array of backend class as key and count number as value
-	 *                if $hasLoggedIn is true only an int is returned
-	 */
-	public function countUsers($hasLoggedIn = false) {
-		if ($hasLoggedIn) {
-			return $this->countSeenUsers();
-		}
-		$userCountStatistics = [];
-		foreach ($this->backends as $backend) {
-			if ($backend->implementsActions(Backend::COUNT_USERS)) {
-				$backendUsers = $backend->countUsers();
-				if($backendUsers !== false) {
-					if($backend instanceof IUserBackend) {
-						$name = $backend->getBackendName();
-					} else {
-						$name = get_class($backend);
-					}
-					if(isset($userCountStatistics[$name])) {
-						$userCountStatistics[$name] += $backendUsers;
-					} else {
-						$userCountStatistics[$name] = $backendUsers;
-					}
-				}
-			}
-		}
-		return $userCountStatistics;
-	}
-
-	/**
-	 * The callback is executed for each user on each backend.
-	 * If the callback returns false no further users will be retrieved.
-	 *
-	 * @param \Closure $callback
-	 * @param string $search
-	 * @param boolean $onlySeen when true only users that have a lastLogin entry
-	 *                in the preferences table will be affected
-	 * @since 9.0.0
-	 */
-	public function callForAllUsers(\Closure $callback, $search = '', $onlySeen = false) {
-		if ($onlySeen) {
-			$this->callForSeenUsers($callback);
-		} else {
-			foreach ($this->getBackends() as $backend) {
-				$limit = 500;
-				$offset = 0;
-				do {
-					$users = $backend->getUsers($search, $limit, $offset);
-					foreach ($users as $uid) {
-						if (!$backend->userExists($uid)) {
-							continue;
-						}
-						$user = $this->getUserObject($uid, $backend, false);
-						$return = $callback($user);
-						if ($return === false) {
-							break;
-						}
-					}
-					$offset += $limit;
-				} while (count($users) >= $limit);
-			}
-		}
-	}
-
-	/**
-	 * returns how many users have logged in once
-	 *
-	 * @return int
-	 * @since 11.0.0
-	 */
-	public function countSeenUsers() {
-		$queryBuilder = \OC::$server->getDatabaseConnection()->getQueryBuilder();
-		$queryBuilder->select($queryBuilder->createFunction('COUNT(*)'))
-			->from('preferences')
-			->where($queryBuilder->expr()->eq('appid', $queryBuilder->createNamedParameter('login')))
-			->andWhere($queryBuilder->expr()->eq('configkey', $queryBuilder->createNamedParameter('lastLogin')))
-			->andWhere($queryBuilder->expr()->isNotNull('configvalue'));
-
-		$query = $queryBuilder->execute();
-
-		$result = (int)$query->fetchColumn();
-		$query->closeCursor();
-
-		return $result;
-	}
-
-	/**
-	 * @param \Closure $callback
-	 * @since 11.0.0
-	 */
-	public function callForSeenUsers(\Closure $callback) {
-		$limit = 1000;
-		$offset = 0;
-		do {
-			$userIds = $this->getSeenUserIds($limit, $offset);
-			$offset += $limit;
-			foreach ($userIds as $userId) {
-				foreach ($this->backends as $backend) {
-					if ($backend->userExists($userId)) {
-						$user = $this->getUserObject($userId, $backend, false);
-						$return = $callback($user);
-						if ($return === false) {
-							return;
-						}
-					}
-				}
-			}
-		} while (count($userIds) >= $limit);
-	}
-
-	/**
-	 * Getting all userIds that have a listLogin value requires checking the
-	 * value in php because on oracle you cannot use a clob in a where clause,
-	 * preventing us from doing a not null or length(value) > 0 check.
-	 * 
-	 * @param int $limit
-	 * @param int $offset
-	 * @return string[] with user ids
-	 */
-	private function getSeenUserIds($limit = null, $offset = null) {
-		$queryBuilder = \OC::$server->getDatabaseConnection()->getQueryBuilder();
-		$queryBuilder->select(['userid'])
-			->from('preferences')
-			->where($queryBuilder->expr()->eq(
-				'appid', $queryBuilder->createNamedParameter('login'))
-			)
-			->andWhere($queryBuilder->expr()->eq(
-				'configkey', $queryBuilder->createNamedParameter('lastLogin'))
-			)
-			->andWhere($queryBuilder->expr()->isNotNull('configvalue')
-			);
-
-		if ($limit !== null) {
-			$queryBuilder->setMaxResults($limit);
-		}
-		if ($offset !== null) {
-			$queryBuilder->setFirstResult($offset);
-		}
-		$query = $queryBuilder->execute();
-		$result = [];
-
-		while ($row = $query->fetch()) {
-			$result[] = $row['userid'];
-		}
-
-		$query->closeCursor();
-
-		return $result;
-	}
-
-	/**
-	 * @param string $email
-	 * @return IUser[]
-	 * @since 9.1.0
-	 */
-	public function getByEmail($email) {
-		$userIds = $this->config->getUsersForUserValue('settings', 'email', $email);
-
-		return array_map(function($uid) {
-			return $this->get($uid);
-		}, $userIds);
-	}
+    /**
+     * @var \OCP\UserInterface[] $backends
+     */
+    private $backends = array();
+
+    /**
+     * @var \OC\User\User[] $cachedUsers
+     */
+    private $cachedUsers = array();
+
+    /**
+     * @var \OCP\IConfig $config
+     */
+    private $config;
+
+    /**
+     * @param \OCP\IConfig $config
+     */
+    public function __construct(IConfig $config) {
+        $this->config = $config;
+        $cachedUsers = &$this->cachedUsers;
+        $this->listen('\OC\User', 'postDelete', function ($user) use (&$cachedUsers) {
+            /** @var \OC\User\User $user */
+            unset($cachedUsers[$user->getUID()]);
+        });
+    }
+
+    /**
+     * Get the active backends
+     * @return \OCP\UserInterface[]
+     */
+    public function getBackends() {
+        return $this->backends;
+    }
+
+    /**
+     * register a user backend
+     *
+     * @param \OCP\UserInterface $backend
+     */
+    public function registerBackend($backend) {
+        $this->backends[] = $backend;
+    }
+
+    /**
+     * remove a user backend
+     *
+     * @param \OCP\UserInterface $backend
+     */
+    public function removeBackend($backend) {
+        $this->cachedUsers = array();
+        if (($i = array_search($backend, $this->backends)) !== false) {
+            unset($this->backends[$i]);
+        }
+    }
+
+    /**
+     * remove all user backends
+     */
+    public function clearBackends() {
+        $this->cachedUsers = array();
+        $this->backends = array();
+    }
+
+    /**
+     * get a user by user id
+     *
+     * @param string $uid
+     * @return \OC\User\User|null Either the user or null if the specified user does not exist
+     */
+    public function get($uid) {
+        if (isset($this->cachedUsers[$uid])) { //check the cache first to prevent having to loop over the backends
+            return $this->cachedUsers[$uid];
+        }
+        foreach ($this->backends as $backend) {
+            if ($backend->userExists($uid)) {
+                return $this->getUserObject($uid, $backend);
+            }
+        }
+        return null;
+    }
+
+    /**
+     * get or construct the user object
+     *
+     * @param string $uid
+     * @param \OCP\UserInterface $backend
+     * @param bool $cacheUser If false the newly created user object will not be cached
+     * @return \OC\User\User
+     */
+    protected function getUserObject($uid, $backend, $cacheUser = true) {
+        if (isset($this->cachedUsers[$uid])) {
+            return $this->cachedUsers[$uid];
+        }
+
+        if (method_exists($backend, 'loginName2UserName')) {
+            $loginName = $backend->loginName2UserName($uid);
+            if ($loginName !== false) {
+                $uid = $loginName;
+            }
+            if (isset($this->cachedUsers[$uid])) {
+                return $this->cachedUsers[$uid];
+            }
+        }
+
+        $user = new User($uid, $backend, $this, $this->config);
+        if ($cacheUser) {
+            $this->cachedUsers[$uid] = $user;
+        }
+        return $user;
+    }
+
+    /**
+     * check if a user exists
+     *
+     * @param string $uid
+     * @return bool
+     */
+    public function userExists($uid) {
+        $user = $this->get($uid);
+        return ($user !== null);
+    }
+
+    /**
+     * Check if the password is valid for the user
+     *
+     * @param string $loginName
+     * @param string $password
+     * @return mixed the User object on success, false otherwise
+     */
+    public function checkPassword($loginName, $password) {
+        $result = $this->checkPasswordNoLogging($loginName, $password);
+
+        if ($result === false) {
+            \OC::$server->getLogger()->warning('Login failed: \''. $loginName .'\' (Remote IP: \''. \OC::$server->getRequest()->getRemoteAddress(). '\')', ['app' => 'core']);
+        }
+
+        return $result;
+    }
+
+    /**
+     * Check if the password is valid for the user
+     *
+     * @internal
+     * @param string $loginName
+     * @param string $password
+     * @return mixed the User object on success, false otherwise
+     */
+    public function checkPasswordNoLogging($loginName, $password) {
+        $loginName = str_replace("\0", '', $loginName);
+        $password = str_replace("\0", '', $password);
+
+        foreach ($this->backends as $backend) {
+            if ($backend->implementsActions(Backend::CHECK_PASSWORD)) {
+                $uid = $backend->checkPassword($loginName, $password);
+                if ($uid !== false) {
+                    return $this->getUserObject($uid, $backend);
+                }
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * search by user id
+     *
+     * @param string $pattern
+     * @param int $limit
+     * @param int $offset
+     * @return \OC\User\User[]
+     */
+    public function search($pattern, $limit = null, $offset = null) {
+        $users = array();
+        foreach ($this->backends as $backend) {
+            $backendUsers = $backend->getUsers($pattern, $limit, $offset);
+            if (is_array($backendUsers)) {
+                foreach ($backendUsers as $uid) {
+                    $users[$uid] = $this->getUserObject($uid, $backend);
+                }
+            }
+        }
+
+        uasort($users, function ($a, $b) {
+            /**
+             * @var \OC\User\User $a
+             * @var \OC\User\User $b
+             */
+            return strcmp($a->getUID(), $b->getUID());
+        });
+        return $users;
+    }
+
+    /**
+     * search by displayName
+     *
+     * @param string $pattern
+     * @param int $limit
+     * @param int $offset
+     * @return \OC\User\User[]
+     */
+    public function searchDisplayName($pattern, $limit = null, $offset = null) {
+        $users = array();
+        foreach ($this->backends as $backend) {
+            $backendUsers = $backend->getDisplayNames($pattern, $limit, $offset);
+            if (is_array($backendUsers)) {
+                foreach ($backendUsers as $uid => $displayName) {
+                    $users[] = $this->getUserObject($uid, $backend);
+                }
+            }
+        }
+
+        usort($users, function ($a, $b) {
+            /**
+             * @var \OC\User\User $a
+             * @var \OC\User\User $b
+             */
+            return strcmp(strtolower($a->getDisplayName()), strtolower($b->getDisplayName()));
+        });
+        return $users;
+    }
+
+    /**
+     * @param string $uid
+     * @param string $password
+     * @throws \Exception
+     * @return bool|\OC\User\User the created user or false
+     */
+    public function createUser($uid, $password) {
+        $l = \OC::$server->getL10N('lib');
+        // Check the name for bad characters
+        // Allowed are: "a-z", "A-Z", "0-9" and "_.@-'"
+        if (preg_match('/[^a-zA-Z0-9 _\.@\-\']/', $uid)) {
+            throw new \Exception($l->t('Only the following characters are allowed in a username:'
+                . ' "a-z", "A-Z", "0-9", and "_.@-\'"'));
+        }
+        // No empty username
+        if (trim($uid) == '') {
+            throw new \Exception($l->t('A valid username must be provided'));
+        }
+        // No whitespace at the beginning or at the end
+        if (trim($uid) !== $uid) {
+            throw new \Exception($l->t('Username contains whitespace at the beginning or at the end'));
+        }
+        // Username only consists of 1 or 2 dots (directory traversal)
+        if (preg_match('/^\.{1,2}$/', $uid)) {
+            throw new \Exception($l->t('Username must not consist of dots only'));
+        }
+        // No empty password
+        if (trim($password) == '') {
+            throw new \Exception($l->t('A valid password must be provided'));
+        }
+
+        // Check if user already exists
+        if ($this->userExists($uid)) {
+            throw new \Exception($l->t('The username is already being used'));
+        }
+
+        $this->emit('\OC\User', 'preCreateUser', array($uid, $password));
+        foreach ($this->backends as $backend) {
+            if ($backend->implementsActions(Backend::CREATE_USER)) {
+                $backend->createUser($uid, $password);
+                $user = $this->getUserObject($uid, $backend);
+                $this->emit('\OC\User', 'postCreateUser', array($user, $password));
+                return $user;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * returns how many users per backend exist (if supported by backend)
+     *
+     * @param boolean $hasLoggedIn when true only users that have a lastLogin
+     *                entry in the preferences table will be affected
+     * @return array|int an array of backend class as key and count number as value
+     *                if $hasLoggedIn is true only an int is returned
+     */
+    public function countUsers($hasLoggedIn = false) {
+        if ($hasLoggedIn) {
+            return $this->countSeenUsers();
+        }
+        $userCountStatistics = [];
+        foreach ($this->backends as $backend) {
+            if ($backend->implementsActions(Backend::COUNT_USERS)) {
+                $backendUsers = $backend->countUsers();
+                if($backendUsers !== false) {
+                    if($backend instanceof IUserBackend) {
+                        $name = $backend->getBackendName();
+                    } else {
+                        $name = get_class($backend);
+                    }
+                    if(isset($userCountStatistics[$name])) {
+                        $userCountStatistics[$name] += $backendUsers;
+                    } else {
+                        $userCountStatistics[$name] = $backendUsers;
+                    }
+                }
+            }
+        }
+        return $userCountStatistics;
+    }
+
+    /**
+     * The callback is executed for each user on each backend.
+     * If the callback returns false no further users will be retrieved.
+     *
+     * @param \Closure $callback
+     * @param string $search
+     * @param boolean $onlySeen when true only users that have a lastLogin entry
+     *                in the preferences table will be affected
+     * @since 9.0.0
+     */
+    public function callForAllUsers(\Closure $callback, $search = '', $onlySeen = false) {
+        if ($onlySeen) {
+            $this->callForSeenUsers($callback);
+        } else {
+            foreach ($this->getBackends() as $backend) {
+                $limit = 500;
+                $offset = 0;
+                do {
+                    $users = $backend->getUsers($search, $limit, $offset);
+                    foreach ($users as $uid) {
+                        if (!$backend->userExists($uid)) {
+                            continue;
+                        }
+                        $user = $this->getUserObject($uid, $backend, false);
+                        $return = $callback($user);
+                        if ($return === false) {
+                            break;
+                        }
+                    }
+                    $offset += $limit;
+                } while (count($users) >= $limit);
+            }
+        }
+    }
+
+    /**
+     * returns how many users have logged in once
+     *
+     * @return int
+     * @since 11.0.0
+     */
+    public function countSeenUsers() {
+        $queryBuilder = \OC::$server->getDatabaseConnection()->getQueryBuilder();
+        $queryBuilder->select($queryBuilder->createFunction('COUNT(*)'))
+            ->from('preferences')
+            ->where($queryBuilder->expr()->eq('appid', $queryBuilder->createNamedParameter('login')))
+            ->andWhere($queryBuilder->expr()->eq('configkey', $queryBuilder->createNamedParameter('lastLogin')))
+            ->andWhere($queryBuilder->expr()->isNotNull('configvalue'));
+
+        $query = $queryBuilder->execute();
+
+        $result = (int)$query->fetchColumn();
+        $query->closeCursor();
+
+        return $result;
+    }
+
+    /**
+     * @param \Closure $callback
+     * @since 11.0.0
+     */
+    public function callForSeenUsers(\Closure $callback) {
+        $limit = 1000;
+        $offset = 0;
+        do {
+            $userIds = $this->getSeenUserIds($limit, $offset);
+            $offset += $limit;
+            foreach ($userIds as $userId) {
+                foreach ($this->backends as $backend) {
+                    if ($backend->userExists($userId)) {
+                        $user = $this->getUserObject($userId, $backend, false);
+                        $return = $callback($user);
+                        if ($return === false) {
+                            return;
+                        }
+                    }
+                }
+            }
+        } while (count($userIds) >= $limit);
+    }
+
+    /**
+     * Getting all userIds that have a listLogin value requires checking the
+     * value in php because on oracle you cannot use a clob in a where clause,
+     * preventing us from doing a not null or length(value) > 0 check.
+     * 
+     * @param int $limit
+     * @param int $offset
+     * @return string[] with user ids
+     */
+    private function getSeenUserIds($limit = null, $offset = null) {
+        $queryBuilder = \OC::$server->getDatabaseConnection()->getQueryBuilder();
+        $queryBuilder->select(['userid'])
+            ->from('preferences')
+            ->where($queryBuilder->expr()->eq(
+                'appid', $queryBuilder->createNamedParameter('login'))
+            )
+            ->andWhere($queryBuilder->expr()->eq(
+                'configkey', $queryBuilder->createNamedParameter('lastLogin'))
+            )
+            ->andWhere($queryBuilder->expr()->isNotNull('configvalue')
+            );
+
+        if ($limit !== null) {
+            $queryBuilder->setMaxResults($limit);
+        }
+        if ($offset !== null) {
+            $queryBuilder->setFirstResult($offset);
+        }
+        $query = $queryBuilder->execute();
+        $result = [];
+
+        while ($row = $query->fetch()) {
+            $result[] = $row['userid'];
+        }
+
+        $query->closeCursor();
+
+        return $result;
+    }
+
+    /**
+     * @param string $email
+     * @return IUser[]
+     * @since 9.1.0
+     */
+    public function getByEmail($email) {
+        $userIds = $this->config->getUsersForUserValue('settings', 'email', $email);
+
+        return array_map(function($uid) {
+            return $this->get($uid);
+        }, $userIds);
+    }
 }