/Classes/TYPO3/FLOW3/Cache/Backend/MemcachedBackend.php
PHP | 375 lines | 152 code | 32 blank | 191 comment | 29 complexity | d4daad0d67e735bdc75658f762ce7b36 MD5 | raw file
Possible License(s): BSD-3-Clause, LGPL-3.0
- <?php
- namespace TYPO3\FLOW3\Cache\Backend;
- /* *
- * This script belongs to the FLOW3 framework. *
- * *
- * It is free software; you can redistribute it and/or modify it under *
- * the terms of the GNU Lesser General Public License, either version 3 *
- * of the License, or (at your option) any later version. *
- * *
- * The TYPO3 project - inspiring people to share! *
- * */
- /**
- * A caching backend which stores cache entries by using Memcached.
- *
- * This backend uses the following types of Memcache keys:
- * - tag_xxx
- * xxx is tag name, value is array of associated identifiers identifier. This
- * is "forward" tag index. It is mainly used for obtaining content by tag
- * (get identifier by tag -> get content by identifier)
- * - ident_xxx
- * xxx is identifier, value is array of associated tags. This is "reverse" tag
- * index. It provides quick access for all tags associated with this identifier
- * and used when removing the identifier
- * - tagIndex
- * Value is a List of all tags (array)
- *
- * Each key is prepended with a prefix. By default prefix consists from two parts
- * separated by underscore character and ends in yet another underscore character:
- * - "FLOW3"
- * - MD5 of script path and filename and SAPI name
- * This prefix makes sure that keys from the different installations do not
- * conflict.
- *
- * Note: When using the Memcached backend to store values of more than ~1 MB, the
- * data will be split into chunks to make them fit into the memcached limits.
- *
- * @api
- */
- class MemcachedBackend extends AbstractBackend implements TaggableBackendInterface {
- /**
- * Max bucket size, (1024*1024)-42 bytes
- * @var int
- */
- const MAX_BUCKET_SIZE = 1048534;
- /**
- * Instance of the PHP Memcache class
- *
- * @var \Memcache
- */
- protected $memcache;
- /**
- * Array of Memcache server configurations
- *
- * @var array
- */
- protected $servers = array();
- /**
- * Indicates whether the memcache uses compression or not (requires zlib),
- * either 0 or MEMCACHE_COMPRESSED
- *
- * @var int
- */
- protected $flags;
- /**
- * A prefix to separate stored data from other data possible stored in the memcache
- *
- * @var string
- */
- protected $identifierPrefix;
- /**
- * Constructs this backend
- *
- * @param \TYPO3\FLOW3\Core\ApplicationContext $context FLOW3's application context
- * @param array $options Configuration options - depends on the actual backend
- * @throws \TYPO3\FLOW3\Cache\Exception
- */
- public function __construct(\TYPO3\FLOW3\Core\ApplicationContext $context, array $options = array()) {
- if (!extension_loaded('memcache')) throw new \TYPO3\FLOW3\Cache\Exception('The PHP extension "memcache" must be installed and loaded in order to use the Memcached backend.', 1213987706);
- parent::__construct($context, $options);
- }
- /**
- * Setter for servers to be used. Expects an array, the values are expected
- * to be formatted like "<host>[:<port>]" or "unix://<path>"
- *
- * @param array $servers An array of servers to add.
- * @return void
- * @api
- */
- protected function setServers(array $servers) {
- $this->servers = $servers;
- }
- /**
- * Setter for compression flags bit
- *
- * @param boolean $useCompression
- * @return void
- * @api
- */
- protected function setCompression($useCompression) {
- if ($useCompression === TRUE) {
- $this->flags ^= MEMCACHE_COMPRESSED;
- } else {
- $this->flags &= ~MEMCACHE_COMPRESSED;
- }
- }
- /**
- * Initializes the identifier prefix
- *
- * @return void
- * @throws \TYPO3\FLOW3\Cache\Exception
- */
- public function initializeObject() {
- if (!count($this->servers)) throw new \TYPO3\FLOW3\Cache\Exception('No servers were given to Memcache', 1213115903);
- $this->memcache = new \Memcache();
- $defaultPort = ini_get('memcache.default_port');
- foreach ($this->servers as $server) {
- if (substr($server, 0, 7) === 'unix://') {
- $host = $server;
- $port = 0;
- } else {
- if (substr($server, 0, 6) === 'tcp://') {
- $server = substr($server, 6);
- }
- if (strpos($server, ':') !== FALSE) {
- list($host, $port) = explode(':', $server, 2);
- } else {
- $host = $server;
- $port = $defaultPort;
- }
- }
- $this->memcache->addServer($host, $port);
- }
- }
- /**
- * Initializes the identifier prefix when setting the cache.
- *
- * @param \TYPO3\FLOW3\Cache\Frontend\FrontendInterface $cache
- * @return void
- */
- public function setCache(\TYPO3\FLOW3\Cache\Frontend\FrontendInterface $cache) {
- parent::setCache($cache);
- $this->identifierPrefix = 'FLOW3_' . md5($cache->getIdentifier() . \TYPO3\FLOW3\Utility\Files::getUnixStylePath($_SERVER['SCRIPT_FILENAME']) . PHP_SAPI) . '_';
- }
- /**
- * Saves data in the cache.
- *
- * @param string $entryIdentifier An identifier for this specific cache entry
- * @param string $data The data to be stored
- * @param array $tags Tags to associate with this cache entry
- * @param integer $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited lifetime.
- * @return void
- * @throws \TYPO3\FLOW3\Cache\Exception if no cache frontend has been set.
- * @throws \InvalidArgumentException if the identifier is not valid or the final memcached key is longer than 250 characters
- * @throws \TYPO3\FLOW3\Cache\Exception\InvalidDataException if $data is not a string
- * @api
- */
- public function set($entryIdentifier, $data, array $tags = array(), $lifetime = NULL) {
- if (strlen($this->identifierPrefix . $entryIdentifier) > 250) throw new \InvalidArgumentException('Could not set value. Key more than 250 characters (' . $this->identifierPrefix . $entryIdentifier . ').', 1232969508);
- if (!$this->cache instanceof \TYPO3\FLOW3\Cache\Frontend\FrontendInterface) throw new \TYPO3\FLOW3\Cache\Exception('No cache frontend has been set yet via setCache().', 1207149215);
- if (!is_string($data)) throw new \TYPO3\FLOW3\Cache\Exception\InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1207149231);
- $tags[] = '%MEMCACHEBE%' . $this->cacheIdentifier;
- $expiration = $lifetime !== NULL ? $lifetime : $this->defaultLifetime;
- // Memcached consideres values over 2592000 sec (30 days) as UNIX timestamp
- // thus $expiration should be converted from lifetime to UNIX timestamp
- if ($expiration > 2592000) {
- $expiration += time();
- }
- try {
- if (strlen($data) > self::MAX_BUCKET_SIZE) {
- $data = str_split($data, self::MAX_BUCKET_SIZE - 1024);
- $success = TRUE;
- $chunkNumber = 1;
- foreach ($data as $chunk) {
- $success = $success && $this->memcache->set($this->identifierPrefix . $entryIdentifier . '_chunk_' . $chunkNumber, $chunk, $this->flags, $expiration);
- $chunkNumber++;
- }
- $success = $success && $this->memcache->set($this->identifierPrefix . $entryIdentifier, 'FLOW3*chunked:' . $chunkNumber, $this->flags, $expiration);
- } else {
- $success = $this->memcache->set($this->identifierPrefix . $entryIdentifier, $data, $this->flags, $expiration);
- }
- if ($success === TRUE) {
- $this->removeIdentifierFromAllTags($entryIdentifier);
- $this->addIdentifierToTags($entryIdentifier, $tags);
- } else {
- throw new \TYPO3\FLOW3\Cache\Exception('Could not set value on memcache server.', 1275830266);
- }
- } catch (\Exception $exception) {
- throw new \TYPO3\FLOW3\Cache\Exception('Could not set value. ' . $exception->getMessage(), 1207208100);
- }
- }
- /**
- * Loads data from the cache.
- *
- * @param string $entryIdentifier An identifier which describes the cache entry to load
- * @return mixed The cache entry's content as a string or FALSE if the cache entry could not be loaded
- * @api
- */
- public function get($entryIdentifier) {
- $value = $this->memcache->get($this->identifierPrefix . $entryIdentifier);
- if (substr($value, 0, 14) === 'FLOW3*chunked:') {
- list( , $chunkCount) = explode(':', $value);
- $value = '';
- for ($chunkNumber = 1 ; $chunkNumber < $chunkCount; $chunkNumber++) {
- $value .= $this->memcache->get($this->identifierPrefix . $entryIdentifier . '_chunk_' . $chunkNumber);
- }
- }
- return $value;
- }
- /**
- * Checks if a cache entry with the specified identifier exists.
- *
- * @param string $entryIdentifier An identifier specifying the cache entry
- * @return boolean TRUE if such an entry exists, FALSE if not
- * @api
- */
- public function has($entryIdentifier) {
- return $this->memcache->get($this->identifierPrefix . $entryIdentifier) !== FALSE;
- }
- /**
- * Removes all cache entries matching the specified identifier.
- * Usually this only affects one entry but if - for what reason ever -
- * old entries for the identifier still exist, they are removed as well.
- *
- * @param string $entryIdentifier Specifies the cache entry to remove
- * @return boolean TRUE if (at least) an entry could be removed or FALSE if no entry was found
- * @api
- */
- public function remove($entryIdentifier) {
- $this->removeIdentifierFromAllTags($entryIdentifier);
- return $this->memcache->delete($this->identifierPrefix . $entryIdentifier, 0);
- }
- /**
- * Finds and returns all cache entry identifiers which are tagged by the
- * specified tag.
- *
- * @param string $tag The tag to search for
- * @return array An array with identifiers of all matching entries. An empty array if no entries matched
- * @api
- */
- public function findIdentifiersByTag($tag) {
- $identifiers = $this->memcache->get($this->identifierPrefix . 'tag_' . $tag);
- if ($identifiers !== FALSE) {
- return (array) $identifiers;
- } else {
- return array();
- }
- }
- /**
- * Finds all tags for the given identifier. This function uses reverse tag
- * index to search for tags.
- *
- * @param string $identifier Identifier to find tags by
- * @return array Array with tags
- */
- protected function findTagsByIdentifier($identifier) {
- $tags = $this->memcache->get($this->identifierPrefix . 'ident_' . $identifier);
- return ($tags === FALSE ? array() : (array)$tags);
- }
- /**
- * Removes all cache entries of this cache.
- *
- * @return void
- * @throws \TYPO3\FLOW3\Cache\Exception
- * @api
- */
- public function flush() {
- if (!$this->cache instanceof \TYPO3\FLOW3\Cache\Frontend\FrontendInterface) throw new \TYPO3\FLOW3\Cache\Exception('Yet no cache frontend has been set via setCache().', 1204111376);
- $this->flushByTag('%MEMCACHEBE%' . $this->cacheIdentifier);
- }
- /**
- * Removes all cache entries of this cache which are tagged by the specified tag.
- *
- * @param string $tag The tag the entries must have
- * @return void
- * @api
- */
- public function flushByTag($tag) {
- $identifiers = $this->findIdentifiersByTag($tag);
- foreach ($identifiers as $identifier) {
- $this->remove($identifier);
- }
- }
- /**
- * Associates the identifier with the given tags
- *
- * @param string $entryIdentifier
- * @param array $tags
- * @return void
- */
- protected function addIdentifierToTags($entryIdentifier, array $tags) {
- foreach ($tags as $tag) {
- // Update tag-to-identifier index
- $identifiers = $this->findIdentifiersByTag($tag);
- if (array_search($entryIdentifier, $identifiers) === FALSE) {
- $identifiers[] = $entryIdentifier;
- $this->memcache->set($this->identifierPrefix . 'tag_' . $tag, $identifiers);
- }
- // Update identifier-to-tag index
- $existingTags = $this->findTagsByIdentifier($entryIdentifier);
- if (array_search($tag, $existingTags) === FALSE) {
- $this->memcache->set($this->identifierPrefix . 'ident_' . $entryIdentifier, array_merge($existingTags, $tags));
- }
- }
- }
- /**
- * Removes association of the identifier with the given tags
- *
- * @param string $entryIdentifier
- * @return void
- */
- protected function removeIdentifierFromAllTags($entryIdentifier) {
- // Get tags for this identifier
- $tags = $this->findTagsByIdentifier($entryIdentifier);
- // Deassociate tags with this identifier
- foreach ($tags as $tag) {
- $identifiers = $this->findIdentifiersByTag($tag);
- // Formally array_search() below should never return false due to
- // the behavior of findTagsByIdentifier(). But if reverse index is
- // corrupted, we still can get 'false' from array_search(). This is
- // not a problem because we are removing this identifier from
- // anywhere.
- if (($key = array_search($entryIdentifier, $identifiers)) !== FALSE) {
- unset($identifiers[$key]);
- if (count($identifiers)) {
- $this->memcache->set($this->identifierPrefix . 'tag_' . $tag, $identifiers);
- } else {
- $this->memcache->delete($this->identifierPrefix . 'tag_' . $tag, 0);
- }
- }
- }
- // Clear reverse tag index for this identifier
- $this->memcache->delete($this->identifierPrefix . 'ident_' . $entryIdentifier, 0);
- }
- /**
- * Does nothing, as memcached does GC itself
- *
- * @return void
- * @api
- */
- public function collectGarbage() {
- }
- }
- ?>