CRM/Utils/Cache/Memcache.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | Copyright CiviCRM LLC. All rights reserved.                        |
   5  |                                                                    |
   6  | This work is published under the GNU AGPLv3 license with some      |
   7  | permitted exceptions and without any warranty. For full license    |
   8  | and copyright information, see https://civicrm.org/licensing       |
   9  +--------------------------------------------------------------------+
  10  */
  11
  12 /**
  13  *
  14  * @package CRM
  15  * @copyright CiviCRM LLC https://civicrm.org/licensing
  16  */
  17 class CRM_Utils_Cache_Memcache implements CRM_Utils_Cache_Interface {
  18
  19   // TODO Consider native implementation.
  20   use CRM_Utils_Cache_NaiveMultipleTrait;
  21
  22   const DEFAULT_HOST = 'localhost';
  23   const DEFAULT_PORT = 11211;
  24   const DEFAULT_TIMEOUT = 3600;
  25   const DEFAULT_PREFIX = '';
  26
  27   /**
  28    * If another process clears namespace, we'll find out in ~5 sec.
  29    */
  30   const NS_LOCAL_TTL = 5;
  31
  32   /**
  33    * The host name of the memcached server.
  34    *
  35    * @var string
  36    */
  37   protected $_host = self::DEFAULT_HOST;
  38
  39   /**
  40    * The port on which to connect on.
  41    *
  42    * @var int
  43    */
  44   protected $_port = self::DEFAULT_PORT;
  45
  46   /**
  47    * The default timeout to use.
  48    *
  49    * @var int
  50    */
  51   protected $_timeout = self::DEFAULT_TIMEOUT;
  52
  53   /**
  54    * The prefix prepended to cache keys.
  55    *
  56    * If we are using the same memcache instance for multiple CiviCRM
  57    * installs, we must have a unique prefix for each install to prevent
  58    * the keys from clobbering each other.
  59    *
  60    * @var string
  61    */
  62   protected $_prefix = self::DEFAULT_PREFIX;
  63
  64   /**
  65    * The actual memcache object.
  66    *
  67    * @var Memcache
  68    */
  69   protected $_cache;
  70
  71   /**
  72    * @var NULL|array
  73    *
  74    * This is the effective prefix. It may be bumped up whenever the dataset is flushed.
  75    *
  76    * @see https://github.com/memcached/memcached/wiki/ProgrammingTricks#deleting-by-namespace
  77    */
  78   protected $_truePrefix = NULL;
  79
  80   /**
  81    * Constructor.
  82    *
  83    * @param array $config
  84    *   An array of configuration params.
  85    *
  86    * @return \CRM_Utils_Cache_Memcache
  87    */
  88   public function __construct($config) {
  89     if (isset($config['host'])) {
  90       $this->_host = $config['host'];
  91     }
  92     if (isset($config['port'])) {
  93       $this->_port = $config['port'];
  94     }
  95     if (isset($config['timeout'])) {
  96       $this->_timeout = $config['timeout'];
  97     }
  98     if (isset($config['prefix'])) {
  99       $this->_prefix = $config['prefix'];
 100     }
 101
 102     $this->_cache = new Memcache();
 103
 104     if (!$this->_cache->connect($this->_host, $this->_port)) {
 105       // dont use fatal here since we can go in an infinite loop
 106       echo 'Could not connect to Memcached server';
 107       CRM_Utils_System::civiExit();
 108     }
 109   }
 110
 111   /**
 112    * @param $key
 113    * @param $value
 114    * @param null|int|\DateInterval $ttl
 115    *
 116    * @return bool
 117    */
 118   public function set($key, $value, $ttl = NULL) {
 119     CRM_Utils_Cache::assertValidKey($key);
 120     if (is_int($ttl) && $ttl <= 0) {
 121       return $this->delete($key);
 122     }
 123     $expires = CRM_Utils_Date::convertCacheTtlToExpires($ttl, $this->_timeout);
 124     return $this->_cache->set($this->getTruePrefix() . $key, serialize($value), FALSE, $expires);
 125   }
 126
 127   /**
 128    * @param $key
 129    * @param mixed $default
 130    *
 131    * @return mixed
 132    */
 133   public function get($key, $default = NULL) {
 134     CRM_Utils_Cache::assertValidKey($key);
 135     $result = $this->_cache->get($this->getTruePrefix() . $key);
 136     return ($result === FALSE) ? $default : unserialize($result);
 137   }
 138
 139   /**
 140    * @param string $key
 141    *
 142    * @return bool
 143    * @throws \Psr\SimpleCache\CacheException
 144    */
 145   public function has($key) {
 146     CRM_Utils_Cache::assertValidKey($key);
 147     $result = $this->_cache->get($this->getTruePrefix() . $key);
 148     return ($result !== FALSE);
 149   }
 150
 151   /**
 152    * @param $key
 153    *
 154    * @return bool
 155    */
 156   public function delete($key) {
 157     CRM_Utils_Cache::assertValidKey($key);
 158     $this->_cache->delete($this->getTruePrefix() . $key);
 159     return TRUE;
 160   }
 161
 162   /**
 163    * @return bool
 164    */
 165   public function flush() {
 166     $this->_truePrefix = NULL;
 167     $this->_cache->delete($this->_prefix);
 168     return TRUE;
 169   }
 170
 171   public function clear() {
 172     return $this->flush();
 173   }
 174
 175   protected function getTruePrefix() {
 176     if ($this->_truePrefix === NULL || $this->_truePrefix['expires'] < time()) {
 177       $key = $this->_prefix;
 178       $value = $this->_cache->get($key);
 179       if ($value === FALSE) {
 180         $value = uniqid();
 181         // Indefinite.
 182         $this->_cache->set($key, $value, FALSE, 0);
 183       }
 184       $this->_truePrefix = [
 185         'value' => $value,
 186         'expires' => time() + self::NS_LOCAL_TTL,
 187       ];
 188     }
 189     return $this->_prefix . $this->_truePrefix['value'] . '/';
 190   }
 191
 192 }