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 a "local" instance of a StoreableCriteria class with all node
64 * data for insert/update queries. This data set contains data from *this*
67 * @return $dataSetInstance An instance of a StoreableCriteria class
69 private function prepareLocalDataSetInstance () {
70 // Get node/request instances
71 $nodeInstance = Registry::getRegistry()->getInstance('node');
72 $requestInstance = ApplicationHelper::getSelfInstance()->getRequestInstance();
74 // Get a dataset instance
75 $dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_NODE_DHT));
77 // Set the primary key
78 $dataSetInstance->setUniqueKey(self::DB_COLUMN_NODE_ID);
80 // Add public node data
81 $dataSetInstance->addCriteria(self::DB_COLUMN_NODE_TYPE , $requestInstance->getRequestElement('mode'));
82 $dataSetInstance->addCriteria(self::DB_COLUMN_IP_PORT , $nodeInstance->getAddressPort());
83 $dataSetInstance->addCriteria(self::DB_COLUMN_NODE_ID , $nodeInstance->getNodeId());
84 $dataSetInstance->addCriteria(self::DB_COLUMN_SESSION_ID , $nodeInstance->getSessionId());
85 $dataSetInstance->addCriteria(self::DB_COLUMN_PRIVATE_KEY_HASH, $nodeInstance->getPrivateKeyHash());
88 return $dataSetInstance;
92 * Checks whether the local (*this*) node is registered in the DHT by
93 * checking if the external ip/port is found.
95 * @return $isRegistered Whether *this* node is registered in the DHT
97 public function isLocalNodeRegistered () {
99 if (!isset($GLOBALS[__METHOD__])) {
100 // Get a search criteria instance
101 $searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');
104 $nodeInstance = Registry::getRegistry()->getInstance('node');
106 // Add ip:port as criteria
107 $searchInstance->addCriteria(self::DB_COLUMN_IP_PORT, $nodeInstance->getAddressPort());
108 $searchInstance->setLimit(1);
110 // Query database and get a result instance back
111 $resultInstance = $this->doSelectByCriteria($searchInstance);
113 // Cache result of if there is an entry, next() will tell us if the next entry is valid
114 $GLOBALS[__METHOD__] = $resultInstance->next();
118 return $GLOBALS[__METHOD__];
122 * Registeres the local (*this*) node with its data in the DHT.
126 public function registerLocalNode () {
127 // Assert to make sure this method is called with no record in DB (the actual backend of the DHT)
128 assert(!$this->isLocalNodeRegistered());
130 // Get prepared data set instance
131 $dataSetInstance = $this->prepareLocalDataSetInstance();
133 // "Insert" this dataset instance completely into the database
134 $this->queryInsertDataSet($dataSetInstance);
138 * Updates local (*this*) node data in DHT, this is but not limited to the
139 * session id, ip number (and/or hostname) and port number.
143 public function updateLocalNode () {
144 // Assert to make sure this method is called with one record in DB (the actual backend of the DHT)
145 assert($this->isLocalNodeRegistered());
148 $nodeInstance = Registry::getRegistry()->getInstance('node');
150 // Get search criteria
151 $searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');
153 // Search for node id and limit it to one entry
154 $searchInstance->addCriteria(self::DB_COLUMN_NODE_ID, $nodeInstance->getNodeId());
155 $searchInstance->setLimit(1);
157 // Get a prepared dataset instance
158 $dataSetInstance = $this->prepareLocalDataSetInstance();
160 // Set search instance
161 $dataSetInstance->setSearchInstance($searchInstance);
163 // Update DHT database record
164 $this->queryUpdateDataSet($dataSetInstance);
168 * Finds a node by given session id
170 * @param $sessionId Session id to lookup
171 * @return $nodeData Node data array
173 public function findNodeBySessionId ($sessionId) {
174 // Get search criteria
175 $searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');
177 // Search for session id and limit it to one entry
178 $searchInstance->addCriteria(self::DB_COLUMN_SESSION_ID, $sessionId);
179 $searchInstance->setLimit(1);
181 // Query database and get a result instance back
182 $resultInstance = $this->doSelectByCriteria($searchInstance);
184 // Return result instance
185 return $resultInstance;
189 * Registeres a node by given message data.
191 * @param $messageData An array of all message data
192 * @param $handlerInstance An instance of a HandleableMessage class
195 public function registerNodeByMessageData (array $messageData, Handleable $handlerInstance) {
196 // Get a data set instance
197 $dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_NODE_DHT));
199 // Set primary key (session id)
200 $dataSetInstance->setUniqueKey(self::DB_COLUMN_SESSION_ID);
202 // Add all array elements
203 $handlerInstance->addArrayToDataSet($dataSetInstance, $messageData);
205 // Run the "INSERT" query
206 $this->queryInsertDataSet($dataSetInstance);
210 * Updates an existing entry in node list
212 * @param $messageData An array of all message data
213 * @param $handlerInstance An instance of a HandleableMessage class
214 * @param $searchInstance An instance of LocalSearchCriteria class
217 public function updateNodeByMessageData (array $messageData, Handleable $handlerInstance, LocalSearchCriteria $searchInstance) {
218 // Get a data set instance
219 $dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_NODE_DHT));
221 // Add search instance
222 $dataSetInstance->setSearchInstance($searchInstance);
224 // Set primary key (session id)
225 $dataSetInstance->setUniqueKey(self::DB_COLUMN_SESSION_ID);
227 // Add all array elements
228 $handlerInstance->addArrayToDataSet($dataSetInstance, $messageData);
230 // Run the "UPDATE" query
231 $this->queryUpdateDataSet($dataSetInstance);