使用hook实现过滤器before_filter

Ahgigu

MY_Controller:

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class MY_Controller extends CI_Controller {
 
    private $_hooks = array();
 
 
    public function __construct() {
        parent::__construct();
 
        $this->_hooks = $this->before_filter();
        $this->_post_controller_constructor_hooks();
    }
 
    protected function before_filter() {
        return array();
    }
 
    private function _post_controller_constructor_hooks() {
        if (!empty($this->_hooks)) {
            $func = $this->router->fetch_method();
            if(!empty($this->_hooks[$func])){
                $this->hooks->set_post_controller_constructor_hooks($this->_hooks[$func]);
            }
        }
    }
 
}
 

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MY_Hooks:

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class MY_Hooks extends CI_Hooks {
 
    function __construct()
    {
        parent::__construct();
 
        log_message('debug', "BI Hooks Class Initialized");
    }
 
        function _initialize()
        {
                $CFG =& load_class('Config', 'core');
 
                // If hooks are not enabled in the config file
                // there is nothing else to do
 
                if ($CFG->item('enable_hooks') == FALSE)
                {
                        return;
                }
 
                // Grab the "hooks" definition file.
                // If there are no hooks, we're done.
 
                if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/hooks.php'))
                {
                    include(APPPATH.'config/'.ENVIRONMENT.'/hooks.php');
                }
                elseif (is_file(APPPATH.'config/hooks.php'))
                {
                        include(APPPATH.'config/hooks.php');
                }
 
 
                if ( ! isset($hook) OR ! is_array($hook))
                {
                        return;
                }
 
        foreach ($hook as $key => $value) {
            $this->hooks[$value['type']][] = $value;
        }
                $this->enabled = TRUE;
        }
 
        /**
         * Set the post controller constructor hooks
         *
         * @access      public
         * @return      void
         */
    public function set_post_controller_constructor_hooks($hooks){
        $_hooks = array();
        $count = count($hooks);
        $post_hooks = $this->hooks['post_controller_constructor'];
 
        for($i=0; $i<$count; $i++) {
            $_hooks[] = $post_hooks[$this->search_2d_array_by_value($hooks[$i], 'name', $post_hooks)];
        }
 
        $this->hooks['post_controller_constructor'] = array_filter($_hooks);
    }
 
    function search_2d_array_by_value($value, $key_name, $array)
    {
        foreach ($array as $key => $val)
        {
            if ($val[$key_name] == $value)
            {
                return $key;
            }
        }
        return NULL;
    }
 
}
 

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config/hooks:

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$hook['auth'] = array(
    'name' => 'auth',
    'type' => 'post_controller_constructor',
    'class' => 'AccessHook',
    'function' => 'check_access',
    'filename' => 'AccessHook.php',
    'filepath' => 'hooks'
);
$hook['new_message'] = array(
    'name' => 'new_message',
    'type' => 'post_controller_constructor',
    'class' => 'MessageHook',
    'function' => 'new_message',
    'filename' => 'MessageHook.php',
    'filepath' => 'hooks'
);
 

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Post_Controller:

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class Post_Controller extends MY_Controller {
 
public function view(){
 
echo "view post";
}
 
public function list(){
 
echo "list all posts";
}
    protected function before_filter(){
        $_filter = array();
        $_filter['list'] = array('auth','new_message');
        $_filter['view'] = array('new_message', 'auth');
        return $_filter;
    }
 
}
 

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说明：
挂钩在CI的post_controller_constructor这个点上的代码，会在controller构造函数之后action调用之前被执行，
利用这个机制，实现过滤器要解决三个问题：
1.过滤器必须有唯一名字；
1.指定哪些action需要哪些过滤器(通过过滤器名字来设定)；
2.当有多个过滤器时，指定执行先后顺序；

魔侠

这个东西能用来做什么？