CodeIgniter框架钩子机制实现方法【hooks类】

发布:smiling　来源: PHP粉丝网　添加日期：2018-11-15 09:53:33　浏览: 评论：0　

本文实例讲述了CodeIgniter框架钩子机制实现方法。分享给大家供大家参考，具体如下：

记得上一次去到喜啦面试，面试官问我一个问题：codeigniter是如何实现钩子机制的？

当时答不上来，后来回来之后查了一些资料才明白，所以在这里记录一下：

codeigniter的钩子是这样实现的：首先在框架的核心文件system/core/CodeIniter.php文件的 122行，载入Hooks类，接着在该文件中定义了几个挂载点，比如pre_system（129行）、post_controller_constructor（295行）等，并在这些挂载点上面执行hooks类的_call_hook() 方法。

另附codeigniter的hooks类的源代码：

_initialize();

    log_message('debug', "Hooks Class Initialized");

  }



  // --------------------------------------------------------------------



  /**

   * Initialize the Hooks Preferences

   *

   * @access private

   * @return void

   */

  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;

    }



    $this->hooks =& $hook;

    $this->enabled = TRUE;

  }



  // --------------------------------------------------------------------



  /**

   * Call Hook

   *

   * Calls a particular hook

   *

   * @access private

   * @param  string the hook name

   * @return mixed

   */

  function _call_hook($which = '')

  {

    if ( ! $this->enabled OR ! isset($this->hooks[$which]))

    {

      return FALSE;

    }



    if (isset($this->hooks[$which][0]) AND is_array($this->hooks[$which][0]))

    {

      foreach ($this->hooks[$which] as $val)

      {

        $this->_run_hook($val);

      }

    }

    else

    {

      $this->_run_hook($this->hooks[$which]);

    }



    return TRUE;

  }



  // --------------------------------------------------------------------



  /**

   * Run Hook

   *

   * Runs a particular hook

   *

   * @access private

   * @param  array  the hook details

   * @return bool

   */

  function _run_hook($data)

  {

    if ( ! is_array($data))

    {

      return FALSE;

    }



    // -----------------------------------

    // Safety - Prevents run-away loops

    // -----------------------------------



    // If the script being called happens to have the same

    // hook call within it a loop can happen



    if ($this->in_progress == TRUE)

    {

      return;

    }



    // -----------------------------------

    // Set file path

    // -----------------------------------



    if ( ! isset($data['filepath']) OR ! isset($data['filename']))

    {

      return FALSE;

    }



    $filepath = APPPATH.$data['filepath'].'/'.$data['filename'];



    if ( ! file_exists($filepath))

    {

      return FALSE;

    }



    // -----------------------------------

    // Set class/function name

    // -----------------------------------



    $class   = FALSE;

    $function = FALSE;

    $params    = '';



    if (isset($data['class']) AND $data['class'] != '')

    {

      $class = $data['class'];

    }



    if (isset($data['function']))

    {

      $function = $data['function'];

    }



    if (isset($data['params']))

    {

      $params = $data['params'];

    }



    if ($class === FALSE AND $function === FALSE)

    {

      return FALSE;

    }



    // -----------------------------------

    // Set the in_progress flag

    // -----------------------------------



    $this->in_progress = TRUE;



    // -----------------------------------

    // Call the requested class and/or function

    // -----------------------------------



    if ($class !== FALSE)

    {

      if ( ! class_exists($class))

      {

        require($filepath);

      }



      $HOOK = new $class;

      $HOOK->$function($params);

    }

    else

    {

      if ( ! function_exists($function))

      {

        require($filepath);

      }



      $function($params);

    }



    $this->in_progress = FALSE;

    return TRUE;

  } //phpfensi.com



}



// END CI_Hooks class



/* End of file Hooks.php */

/* Location: ./system/core/Hooks.php */