portal/patient/fwk/libs/verysimple/Util/MemCacheProxy.php

   1 <?php
   2 /** @package    verysimple::Util */
   3 require_once("verysimple/Phreeze/CacheMemCache.php");
   4
   5 /**
   6  * MemCacheProxy provides simple access to memcache pool but ignores
   7  * if the server is down instead of throwing an error.
   8  * if the server
   9  * could not be contacted, ServerOffline will be set to true.
  10  *
  11  * @package verysimple::Util
  12  * @author VerySimple Inc.
  13  * @copyright 1997-2007 VerySimple, Inc.
  14  * @license http://www.gnu.org/licenses/lgpl.html LGPL
  15  * @version 1.0
  16  *
  17  */
  18 class MemCacheProxy extends CacheMemCache
  19 {
  20     public $ServerOffline = false;
  21     public $LastServerError = '';
  22
  23     /**
  24      * Acts as a proxy for a MemCache server and fails gracefull if the pool cannot be contacted
  25      *
  26      * @param
  27      *          array in host/port format: array('host1'=>'11211','host2'=>'11211')
  28      * @param
  29      *          string a unique string. prevents conflicts in case multiple apps are using the same memcached server bank
  30      */
  31     public function __construct($server_array = array('localhost'=>'11211'), $uniquePrefix = "CACHE-")
  32     {
  33         if (class_exists('Memcache')) {
  34             $memcache = new Memcache();
  35             foreach (array_keys($server_array) as $host) {
  36                 // print "adding server $host " . $server_array[$host];
  37                 $memcache->addServer($host, $server_array [$host]);
  38             }
  39
  40             parent::__construct($memcache, $uniquePrefix, true);
  41         } else {
  42             $this->LastServerError = 'Memcache client module not installed';
  43             $this->ServerOffline = true;
  44         }
  45     }
  46
  47     /**
  48      * @inheritdocs
  49      */
  50     public function Get($key, $flags = null)
  51     {
  52         // prevent hammering the server if it is down
  53         if ($this->ServerOffline) {
  54             return null;
  55         }
  56
  57         return parent::Get($key, $flags);
  58     }
  59
  60     /**
  61      * @inheritdocs
  62      */
  63     public function Set($key, $val, $flags = null, $timeout = 0)
  64     {
  65         // prevent hammering the server if it is down
  66         if ($this->ServerOffline) {
  67             return null;
  68         }
  69
  70         return parent::Set($key, $val, $flags, $timeout);
  71     }
  72
  73     /**
  74      * @inheritdocs
  75      */
  76     public function Delete($key)
  77     {
  78         // prevent hammering the server if it is down
  79         if ($this->ServerOffline) {
  80             return null;
  81         }
  82
  83         return parent::Delete($key);
  84     }
  85 }