3 * A Node DHT facade class
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 NodeDhtFacade extends BaseDht implements Distributable, Registerable {
26 * Protected constructor
30 protected function __construct () {
31 // Call parent constructor
32 parent::__construct(__CLASS__);
36 * Creates an instance of this class
38 * @return $dhtInstance An instance of a Distributable class
40 public final static function createNodeDhtFacade () {
42 $dhtInstance = new NodeDhtFacade();
44 // Get a database wrapper instance
45 $wrapperInstance = DatabaseWrapperFactory::createWrapperByConfiguredName('node_dht_db_wrapper_class');
47 // Set it in this class
48 $dhtInstance->setWrapperInstance($wrapperInstance);
50 // Return the prepared instance
55 * Initializes the distributed hash table (DHT)
59 public function initDht () {
60 // Is the local node registered?
61 if ($this->getWrapperInstance()->isLocalNodeRegistered()) {
62 // Then only update session id
63 $this->getWrapperInstance()->updateLocalNode();
66 $this->getWrapperInstance()->registerLocalNode();
71 * Bootstraps the DHT by sending out a message to all available nodes
72 * (including itself). This step helps the node to get to know more nodes
73 * which can be queried later for object distribution.
77 public function bootstrapDht () {
81 * Finds a node locally by given session id
83 * @param $sessionId Session id to lookup
84 * @return $nodeData Node-data array
86 public function findNodeLocalBySessionId ($sessionId) {
87 // Default is empty data array
91 * Call the wrapper to do the job and get back a result instance. There
92 * will come back zero or one entry from the wrapper.
94 $resultInstance = $this->getWrapperInstance()->findNodeLocalBySessionId($sessionId);
96 // Is the next entry valid?
97 if ($resultInstance->next()) {
99 * Then load the first entry (more entries are being ignored and
100 * should not happen).
102 $nodeData = $resultInstance->current();
110 * Registers an other node with this node by given message data. The
111 * following data must always be present:
113 * - session-id (for finding the node's record together with below data)
114 * - external-ip (hostname or IP number)
115 * - listen-port (TCP/UDP listen port for inbound connections)
117 * @param $messageArray An array with all minimum message data
118 * @param $handlerInstance An instance of a Handleable class
119 * @param $forceUpdate Optionally force update, don't register (default: register if not found)
121 * @throws NodeSessionIdVerficationException If the node was not found and update is forced
123 public function registerNodeByMessageData (array $messageData, Handleable $handlerInstance, $forceUpdate = FALSE) {
124 // Get a search criteria class
125 $searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');
128 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-FACADE: messageData=' . print_r($messageData, true));
130 // Search for the node's session id and external IP/hostname + TCP/UDP listen port
131 foreach ($handlerInstance->getSearchData() as $key) {
133 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-FACADE: messageData[' . $key . ']=' . $messageData[$key]);
136 assert(isset($messageData[$key]));
139 $searchInstance->addCriteria(str_replace('my-', '', $key), $messageData[$key]);
142 // Only one entry is fine
143 $searchInstance->setLimit(1);
146 $resultInstance = $this->getWrapperInstance()->doSelectByCriteria($searchInstance);
148 // Is there already an entry?
149 if ($resultInstance->next()) {
150 // Entry found, so update it
151 $this->getWrapperInstance()->updateNodeByMessageData($messageData, $handlerInstance, $searchInstance);
152 } elseif ($forceUpdate === FALSE) {
153 // Nothing found, so register it
154 $this->getWrapperInstance()->registerNodeByMessageData($messageData, $handlerInstance);
157 * Do not register non-existent nodes here. This is maybe fatal,
158 * caused by "stolen" session id and/or not matching IP
159 * number/port combination.
161 throw new NodeSessionIdVerficationException(array($this, $messageData), BaseHubSystem::EXCEPTION_NODE_SESSION_ID_NOT_VERIFYING);
164 // Save last exception
165 $handlerInstance->setLastException($this->getWrapperInstance()->getLastException());
169 * Queries the local DHT data(base) for a node list with all supported
170 * object types except the node by given session id.
172 * @param $messageData An array with message data from a node_list request
173 * @param $handlerInstance An instance of a Handleable class
174 * @param $excludeKey Array key which should be excluded
175 * @param $andKey Array of $separator-separated list of elements which all must match
176 * @param $separator Sepator char (1st parameter for explode() call)
177 * @return $nodeList An array with all found nodes
179 public function queryLocalNodeListExceptByMessageData (array $messageData, Handleable $handlerInstance, $excludeKey, $andKey, $separator) {
180 // Make sure both keys are there
181 assert((isset($messageData[$excludeKey])) && (isset($messageData[$andKey])));
184 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-FACADE: messageData=' . print_r($messageData, true));
186 // Get a search criteria class
187 $searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');
190 foreach (explode($separator, $messageData[$andKey]) as $criteria) {
192 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DHT-FACADE: andKey=' . $andKey . ',criteria=' . $criteria);
194 // Add it and leave any 'my-' prefix out
195 $searchInstance->addChoiceCriteria(str_replace('my-', '', $andKey), $criteria);
199 $searchInstance->addExcludeCriteria(str_replace('my-', '', $excludeKey), $messageData[$excludeKey]);
201 // Only X entries are fine
202 $searchInstance->setLimit($this->getConfigInstance()->getConfigEntry('node_dht_list_limit'));
205 $resultInstance = $this->getWrapperInstance()->doSelectByCriteria($searchInstance);
209 while ($resultInstance->next()) {
211 array_push($nodeList, $resultInstance->current());
214 // Save last exception
215 $handlerInstance->setLastException($this->getWrapperInstance()->getLastException());
217 // Return node list (array)
222 * Inserts given node list array (from earlier database result produced by
223 * an other node) into the DHT. This array origins from above method
224 * queryLocalNodeListExceptByMessageData().
226 * @param $nodeList An array from an earlier database result instance
229 public function insertNodeList (array $nodeList) {
230 // If no node is in the list (array), skip the rest of this method silently
231 if (count($nodeList) == 0) {
233 self::createDebugInstance(__CLASS__)->debugOutput('DHT-FACADE: No node record has been returned.');
239 // @TODO Not finish yet
240 $this->partialStub('DHT: Needs implementing to insert ' . count($nodeList) . ' entry(-ies) into DHT.');