CRM/Utils/Cache/Memcache.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | CiviCRM version 5                                                  |
   5  +--------------------------------------------------------------------+
   6  | Copyright CiviCRM LLC (c) 2004-2018                                |
   7  +--------------------------------------------------------------------+
   8  | This file is a part of CiviCRM.                                    |
   9  |                                                                    |
  10  | CiviCRM is free software; you can copy, modify, and distribute it  |
  11  | under the terms of the GNU Affero General Public License           |
  12  | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
  13  |                                                                    |
  14  | CiviCRM is distributed in the hope that it will be useful, but     |
  15  | WITHOUT ANY WARRANTY; without even the implied warranty of         |
  16  | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
  17  | See the GNU Affero General Public License for more details.        |
  18  |                                                                    |
  19  | You should have received a copy of the GNU Affero General Public   |
  20  | License and the CiviCRM Licensing Exception along                  |
  21  | with this program; if not, contact CiviCRM LLC                     |
  22  | at info[AT]civicrm[DOT]org. If you have questions about the        |
  23  | GNU Affero General Public License or the licensing of CiviCRM,     |
  24  | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
  25  +--------------------------------------------------------------------+
  26  */
  27
  28 /**
  29  *
  30  * @package CRM
  31  * @copyright CiviCRM LLC (c) 2004-2018
  32  */
  33 class CRM_Utils_Cache_Memcache implements CRM_Utils_Cache_Interface {
  34
  35   use CRM_Utils_Cache_NaiveMultipleTrait; // TODO Consider native implementation.
  36
  37   const DEFAULT_HOST = 'localhost';
  38   const DEFAULT_PORT = 11211;
  39   const DEFAULT_TIMEOUT = 3600;
  40   const DEFAULT_PREFIX = '';
  41
  42   /**
  43    * If another process clears namespace, we'll find out in ~5 sec.
  44    */
  45   const NS_LOCAL_TTL = 5;
  46
  47   /**
  48    * The host name of the memcached server.
  49    *
  50    * @var string
  51    */
  52   protected $_host = self::DEFAULT_HOST;
  53
  54   /**
  55    * The port on which to connect on.
  56    *
  57    * @var int
  58    */
  59   protected $_port = self::DEFAULT_PORT;
  60
  61   /**
  62    * The default timeout to use.
  63    *
  64    * @var int
  65    */
  66   protected $_timeout = self::DEFAULT_TIMEOUT;
  67
  68   /**
  69    * The prefix prepended to cache keys.
  70    *
  71    * If we are using the same memcache instance for multiple CiviCRM
  72    * installs, we must have a unique prefix for each install to prevent
  73    * the keys from clobbering each other.
  74    *
  75    * @var string
  76    */
  77   protected $_prefix = self::DEFAULT_PREFIX;
  78
  79   /**
  80    * The actual memcache object.
  81    *
  82    * @var Memcache
  83    */
  84   protected $_cache;
  85
  86   /**
  87    * @var NULL|array
  88    *
  89    * This is the effective prefix. It may be bumped up whenever the dataset is flushed.
  90    *
  91    * @see https://github.com/memcached/memcached/wiki/ProgrammingTricks#deleting-by-namespace
  92    */
  93   protected $_truePrefix = NULL;
  94
  95   /**
  96    * Constructor.
  97    *
  98    * @param array $config
  99    *   An array of configuration params.
 100    *
 101    * @return \CRM_Utils_Cache_Memcache
 102    */
 103   public function __construct($config) {
 104     if (isset($config['host'])) {
 105       $this->_host = $config['host'];
 106     }
 107     if (isset($config['port'])) {
 108       $this->_port = $config['port'];
 109     }
 110     if (isset($config['timeout'])) {
 111       $this->_timeout = $config['timeout'];
 112     }
 113     if (isset($config['prefix'])) {
 114       $this->_prefix = $config['prefix'];
 115     }
 116
 117     $this->_cache = new Memcache();
 118
 119     if (!$this->_cache->connect($this->_host, $this->_port)) {
 120       // dont use fatal here since we can go in an infinite loop
 121       echo 'Could not connect to Memcached server';
 122       CRM_Utils_System::civiExit();
 123     }
 124   }
 125
 126   /**
 127    * @param $key
 128    * @param $value
 129    * @param null|int|\DateInterval $ttl
 130    *
 131    * @return bool
 132    */
 133   public function set($key, $value, $ttl = NULL) {
 134     CRM_Utils_Cache::assertValidKey($key);
 135     if (is_int($ttl) && $ttl <= 0) {
 136       return $this->delete($key);
 137     }
 138     $expires = CRM_Utils_Date::convertCacheTtlToExpires($ttl, $this->_timeout);
 139     return $this->_cache->set($this->getTruePrefix() . $key, serialize($value), FALSE, $expires);
 140   }
 141
 142   /**
 143    * @param $key
 144    * @param mixed $default
 145    *
 146    * @return mixed
 147    */
 148   public function get($key, $default = NULL) {
 149     CRM_Utils_Cache::assertValidKey($key);
 150     $result = $this->_cache->get($this->getTruePrefix() . $key);
 151     return ($result === FALSE) ? $default : unserialize($result);
 152   }
 153
 154   /**
 155    * @param string $key
 156    *
 157    * @return bool
 158    * @throws \Psr\SimpleCache\CacheException
 159    */
 160   public function has($key) {
 161     CRM_Utils_Cache::assertValidKey($key);
 162     $result = $this->_cache->get($this->getTruePrefix() . $key);
 163     return ($result !== FALSE);
 164   }
 165
 166
 167   /**
 168    * @param $key
 169    *
 170    * @return bool
 171    */
 172   public function delete($key) {
 173     CRM_Utils_Cache::assertValidKey($key);
 174     $this->_cache->delete($this->getTruePrefix() . $key);
 175     return TRUE;
 176   }
 177
 178   /**
 179    * @return bool
 180    */
 181   public function flush() {
 182     $this->_truePrefix = NULL;
 183     $this->_cache->delete($this->_prefix);
 184     return TRUE;
 185   }
 186
 187   public function clear() {
 188     return $this->flush();
 189   }
 190
 191   protected function getTruePrefix() {
 192     if ($this->_truePrefix === NULL || $this->_truePrefix['expires'] < time()) {
 193       $key = $this->_prefix;
 194       $value = $this->_cache->get($key);
 195       if ($value === FALSE) {
 196         $value = uniqid();
 197         $this->_cache->set($key, $value, FALSE, 0); // Indefinite.
 198       }
 199       $this->_truePrefix = [
 200         'value' => $value,
 201         'expires' => time() + self::NS_LOCAL_TTL,
 202       ];
 203     }
 204     return $this->_prefix . $this->_truePrefix['value'] . '/';
 205   }
 206
 207 }