php hook 之简单例子

<?php
// 应用单例模式
// 建立相应的 plugins 文件夹，并建立 .php 文件放在里面
class plugin
{
   public $actions;
   public $filters;

   private $plugin_dir;
   private static $instance;

   public static function getInstance()
   {
       if(self::$instance == null)
       {
           self::$instance = new self;
       }
       return self::$instance;
   }

   private function __construct()
   {
       $this->actions = $this->filters = array();
       $this->plugin_dir = dirname(__FILE__).'/plugins/';
   }

   public function init()
   {

       $dir_handle = opendir($this->plugin_dir);
       while($m = readdir($dir_handle))
       {
           if($m == '.' || $m == '..')
           {
               continue;
           }else
           {
               $n = $this->plugin_dir . $m;
               if(is_file($n))
               {
                   $f = $n;
               }else
               {
                   $f = $n . '/' . $m . '.php';
               }
               include($f);
           }
       }
       closedir($dir_handle);

   }

   public function do_action($action, $params = array())
   {
       $a = $this->actions[$action];
       $c = $a;
       if(is_callable($c))
       {
           call_user_func_array($c, $params);
       }

   }

   public function add_action($action, $callable)
   {
       $this->actions[$action] = $callable;
   }

   public function add_filter($filter, $callable)
   {
       $this->filters[$filter] = $callable;
   }

   public function apply_filter($filter, $params = array())
   {
       $c = $this->filters[$filter];
       if(is_callable($c))
       {
           call_user_func_array($c, $params);
       }
   }

}

global $pl;
$pl = plugin::getInstance();
$pl->init();

$pl->add_action("tfunc", 'hook'); //引用 pugins目录中的 hook函数而已
$pl->do_action('tfunc', array('aa', 'bb', 'cc'));
//结果为 array(0=>'aa', 1=>'bb', 2 => 'cc') 3表示3个参数

//其中 plugins 中的函数为
/*
function hook($param = array())
{
   $num = func_num_args();
   $str = func_get_args();
   print_r($str);
   print_r($num);
}
*/