Smarty使用Memcache进行缓存

五月 20, 2009 at 7:26 上午 by · Filed under PHP, 编程

默认的Smarty缓存是使用File进行缓存的。在高并发的时候，压力会在IO方面。为了避免在高并发的时候，IO占用高。我写了一个Smarty的插件，将缓存写入Memcache。曾经想过自己写一个模板的，感觉后期的维护比较麻烦，所以。。。。

  1. <?php
  2. /**
  3.  * Smarty Cache Handler<br>
  4.  * utilizing Memcache extension (http://pecl.php.net/package/memcache)<br>
  5.  *
  6.  * Name:     mmcache_cache_handler<br>
  7.  * Type:     Cache Handler<br>
  8.  * Purpose:  Replacement for the file based cache handling of Smarty. mmcache_cache_handler() is
  9.  *           using Memcache extension to minimize disk usage.
  10.  * File:     memcache_cache_handler.php<br>
  11.  * Date:     May 20, 2009<br>
  12.  *
  13.  * Usage Example<br>
  14.  * <pre>
  15.  * $smarty = new Smarty;
  16.  * $smarty->cache_handler_func = 'mmcache_cache_handler';
  17.  * $smarty->caching = true;
  18.  * $smarty->display('index.tpl');
  19.  * </pre>
  20.  *
  21.  * @author   Kim Chow
  22.  * @version  Beta
  23.  *
  24.  * @param    string   $action         Cache operation to perform ( read | write | clear )
  25.  * @param    mixed    $smarty         Reference to an instance of Smarty
  26.  * @param    string   $cache_content  Reference to cached contents
  27.  * @param    string   $tpl_file       Template file name
  28.  * @param    string   $cache_id       Cache identifier
  29.  * @param    string   $compile_id     Compile identifier
  30.  * @param    integer  $exp_time       Expiration time
  31.  * @return   boolean                  TRUE on success, FALSE otherwise
  32.  *
  33.  * @link     http://pecl.php.net/package/memcache
  34.  *           (pecl memcache homepage)
  35.  * @link     http://smarty.php.net/manual/en/section.template.cache.handler.func.php
  36.  *           (Smarty online manual)
  37.  */
  38. function mmcache_cache_handler($action, &$smarty, &$cache_content, $tpl_file = null, $cache_id = null, $compile_id = null, $exp_time = null) {
  39. if (! function_exists ( "memcache_get" )) {
  40. $smarty->trigger_error ( "cache_handler: PHP Extension \"Memcache\" extension (http://pecl.php.net/package/memcache) not installed." );
  41. return false;
  42. }
  44. // Create unique cache id:
  45. // We are using smarty's internal functions here to be as compatible as possible.
  46. $memcache_id = "smarty_memcache_" . $cache_id . "_" . $tpl_file;
  47. $memcache = new memCacheClass ( );
  49. switch ($action) {
  51. case 'read' :
  52. // read cache from shared memory
  53. $cache_content = $memcache->get ( $memcache_id );
  54. if (! is_null ( $cache_content ) && _memcache_hasexpired ( $cache_content )) {
  55. // Cache has been expired so we clear it now by calling ourself with another parameter :)
  56. $cache_content = null;
  57. mmcache_cache_handler ( 'write', $smarty, $cache_content, $tpl_file, $cache_id, $compile_id );
  58. }
  60. $return = true;
  61. break;
  63. case 'write' :
  65. $result = $memcache->set ( $memcache_id, $cache_content, 0, $exp_time );
  67. if (! $result) {
  68. $smarty_obj->_trigger_error_msg ( 'cache_handler: query failed.' );
  69. }
  71. $return = $result;
  73. break;
  75. case 'clear' :
  77. if (empty ( $cache_id )) {
  78. $result = $memcache->delete ( $memcache_id );
  79. }
  81. if (! $result) {
  82. $smarty_obj->_trigger_error_msg ( 'cache_handler: query failed.' );
  83. }
  85. $return = $result;
  87. default :
  88. // error, unknown action
  89. $smarty->trigger_error ( "cache_handler: unknown action \"$action\"" );
  90. $return = false;
  91. break;
  92. }
  93. return $return;
  94. }
  95.  
  96. /**
  97.  * Helper function for mmcache_cache_handler()
  98.  * Checks whether a cached content has been expired by reading the content's header.
  99.  *
  100.  * @access  private
  101.  * @param   string    $cache_content      the cached content
  102.  * @return  boolean                       TRUE if cache has been expired, FALSE otherwise
  103.  *
  104.  * @see     mmcache_cache_handler()
  105.  */
  106. function _memcache_hasexpired(&$cache_content) {
  107. $split = explode ( "\n", $cache_content, 2 );
  108. $attributes = unserialize ( $split [0] );
  110. if ($attributes ['expires'] > 0 && time () > $attributes ['expires'])
  111. return true;
  112. else
  113. return false;
  114. }
  115.  
  116. ?>

上面的例子只是为了做个说明罢了，建议将Memcache进行封装，便于管理。

2009-5-21 修改：
1、加入缓存过期时间

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