[Summary view] [Print] [Text view]

   1  <?php
   2  /*
   3   * Copyright 2008 Google Inc.
   4   *
   5   * Licensed under the Apache License, Version 2.0 (the "License");
   6   * you may not use this file except in compliance with the License.
   7   * You may obtain a copy of the License at
   8   *
   9   *     http://www.apache.org/licenses/LICENSE-2.0
  10   *
  11   * Unless required by applicable law or agreed to in writing, software
  12   * distributed under the License is distributed on an "AS IS" BASIS,
  13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14   * See the License for the specific language governing permissions and
  15   * limitations under the License.
  16   */
  17  
  18  require_once "Google/Cache/Abstract.php";
  19  require_once "Google/Cache/Exception.php";
  20  
  21  /**
  22   * A persistent storage class based on the memcache, which is not
  23   * really very persistent, as soon as you restart your memcache daemon
  24   * the storage will be wiped.
  25   *
  26   * Will use either the memcache or memcached extensions, preferring
  27   * memcached.
  28   *
  29   * @author Chris Chabot <[email protected]>
  30   */
  31  class Google_Cache_Memcache extends Google_Cache_Abstract
  32  {
  33    private $connection = false;
  34    private $mc = false;
  35    private $host;
  36    private $port;
  37  
  38    public function __construct(Google_Client $client)
  39    {
  40      if (!function_exists('memcache_connect') && !class_exists("Memcached")) {
  41        throw new Google_Cache_Exception("Memcache functions not available");
  42      }
  43      if ($client->isAppEngine()) {
  44        // No credentials needed for GAE.
  45        $this->mc = new Memcached();
  46        $this->connection = true;
  47      } else {
  48        $this->host = $client->getClassConfig($this, 'host');
  49        $this->port = $client->getClassConfig($this, 'port');
  50        if (empty($this->host) || empty($this->port)) {
  51          throw new Google_Cache_Exception("You need to supply a valid memcache host and port");
  52        }
  53      }
  54    }
  55    
  56    /**
  57     * @inheritDoc
  58     */
  59    public function get($key, $expiration = false)
  60    {
  61      $this->connect();
  62      $ret = false;
  63      if ($this->mc) {
  64        $ret = $this->mc->get($key);
  65      } else {
  66        $ret = memcache_get($this->connection, $key);
  67      }
  68      if ($ret === false) {
  69        return false;
  70      }
  71      if (is_numeric($expiration) && (time() - $ret['time'] > $expiration)) {
  72        $this->delete($key);
  73        return false;
  74      }
  75      return $ret['data'];
  76    }
  77  
  78    /**
  79     * @inheritDoc
  80     * @param string $key
  81     * @param string $value
  82     * @throws Google_Cache_Exception
  83     */
  84    public function set($key, $value)
  85    {
  86      $this->connect();
  87      // we store it with the cache_time default expiration so objects will at
  88      // least get cleaned eventually.
  89      $data = array('time' => time(), 'data' => $value);
  90      $rc = false;
  91      if ($this->mc) {
  92        $rc = $this->mc->set($key, $data);
  93      } else {
  94        $rc = memcache_set($this->connection, $key, $data, false);
  95      }
  96      if ($rc == false) {
  97        throw new Google_Cache_Exception("Couldn't store data in cache");
  98      }
  99    }
 100  
 101    /**
 102     * @inheritDoc
 103     * @param String $key
 104     */
 105    public function delete($key)
 106    {
 107      $this->connect();
 108      if ($this->mc) {
 109        $this->mc->delete($key, 0);
 110      } else {
 111        memcache_delete($this->connection, $key, 0);
 112      }
 113    }
 114  
 115    /**
 116     * Lazy initialiser for memcache connection. Uses pconnect for to take 
 117     * advantage of the persistence pool where possible. 
 118     */
 119    private function connect()
 120    {
 121      if ($this->connection) {
 122        return;
 123      }
 124  
 125      if (class_exists("Memcached")) {
 126        $this->mc = new Memcached();
 127        $this->mc->addServer($this->host, $this->port);
 128         $this->connection = true;
 129      } else {
 130        $this->connection = memcache_pconnect($this->host, $this->port);
 131      }
 132      
 133      if (! $this->connection) {
 134        throw new Google_Cache_Exception("Couldn't connect to memcache server");
 135      }
 136    }
 137  }