3 * A database wrapper for distributed hash tables
5 * @author Roland Haeder <webmaster@ship-simu.org>
7 * @copyright Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 Hub Developer Team
8 * @license GNU GPL 3.0 or any newer version
9 * @link http://www.ship-simu.org
11 * This program is free software: you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation, either version 3 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program. If not, see <http://www.gnu.org/licenses/>.
24 class NodeDistributedHashTableDatabaseWrapper extends BaseDatabaseWrapper implements NodeDhtWrapper, Registerable {
25 // Constants for database table names
26 const DB_TABLE_NODE_DHT = 'node_dht';
28 // Constants for database column names
29 const DB_COLUMN_NODE_ID = 'node_id';
30 const DB_COLUMN_SESSION_ID = 'session_id';
31 const DB_COLUMN_IP_PORT = 'ip_port';
32 const DB_COLUMN_PRIVATE_KEY = 'private_key';
33 const DB_COLUMN_PRIVATE_KEY_HASH = 'private_key_hash';
34 const DB_COLUMN_NODE_TYPE = 'node_type';
37 * Protected constructor
41 protected function __construct () {
42 // Call parent constructor
43 parent::__construct(__CLASS__);
47 * Creates an instance of this database wrapper by a provided user class
49 * @return $wrapperInstance An instance of the created wrapper class
51 public static final function createNodeDistributedHashTableDatabaseWrapper () {
53 $wrapperInstance = new NodeDistributedHashTableDatabaseWrapper();
55 // Set (primary!) table name
56 $wrapperInstance->setTableName(self::DB_TABLE_NODE_DHT);
58 // Return the instance
59 return $wrapperInstance;
63 * Prepares an instance of a StoreableCriteria class with all node data for
64 * insert/update queries.
66 * @return $dataSetInstance An instance of a StoreableCriteria class
68 private function prepareDataSetInstance () {
69 // Get node/request instances
70 $nodeInstance = Registry::getRegistry()->getInstance('node');
71 $requestInstance = ApplicationHelper::getSelfInstance()->getRequestInstance();
73 // Get a dataset instance
74 $dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_NODE_DHT));
76 // Set the primary key
77 $dataSetInstance->setUniqueKey(self::DB_COLUMN_NODE_ID);
79 // Add public node data
80 $dataSetInstance->addCriteria(self::DB_COLUMN_NODE_TYPE , $requestInstance->getRequestElement('mode'));
81 $dataSetInstance->addCriteria(self::DB_COLUMN_IP_PORT , $nodeInstance->getAddressPort());
82 $dataSetInstance->addCriteria(self::DB_COLUMN_NODE_ID , $nodeInstance->getNodeId());
83 $dataSetInstance->addCriteria(self::DB_COLUMN_SESSION_ID , $nodeInstance->getSessionId());
84 $dataSetInstance->addCriteria(self::DB_COLUMN_PRIVATE_KEY_HASH, $nodeInstance->getPrivateKeyHash());
87 return $dataSetInstance;
91 * Checks whether the local (*this*) node is registered in the DHT by
92 * checking if the external ip/port is found.
94 * @return $isRegistered Whether *this* node is registered in the DHT
96 public function isLocalNodeRegistered () {
98 if (!isset($GLOBALS[__METHOD__])) {
99 // Get a search criteria instance
100 $searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');
103 $nodeInstance = Registry::getRegistry()->getInstance('node');
105 // Add ip:port as criteria
106 $searchInstance->addCriteria(self::DB_COLUMN_IP_PORT, $nodeInstance->getAddressPort());
107 $searchInstance->setLimit(1);
109 // Query database and get a result instance back
110 $resultInstance = $this->doSelectByCriteria($searchInstance);
112 // Cache result of if there is an entry, next() will tell us if the next entry is valid
113 $GLOBALS[__METHOD__] = $resultInstance->next();
117 return $GLOBALS[__METHOD__];
121 * Registeres the local (*this*) node with its data in the DHT.
125 public function registerLocalNode () {
126 // Assert to make sure this method is called with no record in DB (the actual backend of the DHT)
127 assert(!$this->isLocalNodeRegistered());
129 // Get prepared data set instance
130 $dataSetInstance = $this->prepareDataSetInstance();
132 // "Insert" this dataset instance completely into the database
133 $this->queryInsertDataSet($dataSetInstance);
137 * Updates local (*this*) node data in DHT, this is but not limited to the
138 * session id, ip number (and/or hostname) and port number.
142 public function updateLocalNode () {
143 // Assert to make sure this method is called with one record in DB (the actual backend of the DHT)
144 assert($this->isLocalNodeRegistered());
147 $nodeInstance = Registry::getRegistry()->getInstance('node');
149 // Get search criteria
150 $searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');
152 // Search for node id and limit it to one entry
153 $searchInstance->addCriteria(self::DB_COLUMN_NODE_ID, $nodeInstance->getNodeId());
154 $searchInstance->setLimit(1);
156 // Get a prepared dataset instance
157 $dataSetInstance = $this->prepareDataSetInstance();
159 // Set search instance
160 $dataSetInstance->setSearchInstance($searchInstance);
162 // Update DHT database record
163 $this->queryUpdateDataSet($dataSetInstance);
167 * Finds a node by given session id
169 * @param $sessionId Session id to lookup
170 * @return $nodeData Node data array
172 public function findNodeBySessionId ($sessionId) {
173 // Get search criteria
174 $searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');
177 $nodeInstance = Registry::getRegistry()->getInstance('node');
179 // Search for session id and limit it to one entry
180 $searchInstance->addCriteria(self::DB_COLUMN_SESSION_ID, $nodeInstance->getSessionId());
181 $searchInstance->setLimit(1);
183 // Query database and get a result instance back
184 $resultInstance = $this->doSelectByCriteria($searchInstance);
186 // Return result instance
187 return $resultInstance;