【discuzX2.5】$_G在哪？

/source/class/discuz/discuz_application.php(X2.5)
/source/class/class_core.php(X2.0)

在discuz_application.php的_init_env()方法中定义了$_G，里面存放的是一些系统最频繁用到的相关的全局信息，主要是为了后面对各功能实现的便利性。

例如：

我要得知当前用户的UID，那我直接读取$_G['uid']就行了，而不用再二次查询session或者数据库，这样可以提高效率，编写其余的各模块程序，代码量也会变得非常简洁。

【私人例子：

\source\module\course\

edit.php:

$pathHead = $_G["setting"]["attachurl"]."course/title/";

$query = DB :: query("SELECT grouptitle, groupid FROM {$_G['config'][db][1][tablepre]}common_usergroup WHERE type = 'Member' AND creditshigher >= 0");

】

定义：

/source/class/discuz/
discuz_application.php:

class discuz_application extends discuz_base

{

 private function _init_env()

  {

 
 （省略一大段）
                global $_G; //为了声明这是全局变量
 $_G = array(
 'uid' => 0,
 'username' => '',
 'adminid' => 0,
 'groupid' => 1,
 'sid' => '',
 'formhash' => '',
 'connectguest' => 0,
 'timestamp' => TIMESTAMP,
 'starttime' => microtime(true),
 'clientip' => $this->_get_client_ip(),
 'referer' => '',
 'charset' => '',
 'gzipcompress' => '',
 'authkey' => '',
 'timenow' => array(),
 'widthauto' => 0,
 'disabledwidthauto' => 0,


 'PHP_SELF' => '',
 'siteurl' => '',
 'siteroot' => '',
 'siteport' => '',


 'config' => array(),
 'setting' => array(),
 'member' => array(),
 'group' => array(),
 'cookie' => array(),
 'style' => array(),
 'cache' => array(),
 'session' => array(),
 'lang' => array(),
 'my_app' => array(),
 'my_userapp' => array(),


 'fid' => 0,
 'tid' => 0,
 'forum' => array(),
 'thread' => array(),
 'rssauth' => '',


 'home' => array(),
 'space' => array(),


 'block' => array(),
 'article' => array(),


 'action' => array(
 'action' => APPTYPEID,
 'fid' => 0,
 'tid' => 0,
 ),


 'mobile' => '',


 );

 $_G['PHP_SELF'] = dhtmlspecialchars($this->_get_script_url());  $_G['basescript'] = CURSCRIPT;  $_G['basefilename'] = basename($_G['PHP_SELF']);  $sitepath = substr($_G['PHP_SELF'], 0, strrpos($_G['PHP_SELF'], '/'));  if(defined('IN_API')) {  $sitepath = preg_replace("/\/api\/?.*?$/i", '', $sitepath);  } elseif(defined('IN_ARCHIVER')) {  $sitepath = preg_replace("/\/archiver/i", '', $sitepath);  }  $_G['siteurl'] = dhtmlspecialchars('http://'.$_SERVER['HTTP_HOST'].$sitepath.'/');  $url = parse_url($_G['siteurl']);  $_G['siteroot'] = isset($url['path']) ? $url['path'] : '';  $_G['siteport'] = empty($_SERVER['SERVER_PORT']) || $_SERVER['SERVER_PORT'] == '80' ? '' : ':'.$_SERVER['SERVER_PORT'];  if(defined('SUB_DIR')) {  $_G['siteurl'] = str_replace(SUB_DIR, '/', $_G['siteurl']);  $_G['siteroot'] = str_replace(SUB_DIR, '/', $_G['siteroot']);  }  $this->var = & $_G;

 }

}

$pathHead = $_G["setting"]["attachurl"]."course/title/";
$query = DB :: query("SELECT grouptitle, groupid FROM {$_G['config'][db][1][tablepre]}common_usergroup WHERE type = 'Member' AND creditshigher >= 0");
】

定义：
/source/class/discuz/
discuz_application.php:
class discuz_application extends discuz_base
{
	private function _init_env()
 	{
		
		（省略一大段）
                global $_G; //为了声明这是全局变量
		$_G = array(
			'uid' => 0,
			'username' => '',
			'adminid' => 0,
			'groupid' => 1,
			'sid' => '',
			'formhash' => '',
			'connectguest' => 0,
			'timestamp' => TIMESTAMP,
			'starttime' => microtime(true),
			'clientip' => $this->_get_client_ip(),
			'referer' => '',
			'charset' => '',
			'gzipcompress' => '',
			'authkey' => '',
			'timenow' => array(),
			'widthauto' => 0,
			'disabledwidthauto' => 0,


			'PHP_SELF' => '',
			'siteurl' => '',
			'siteroot' => '',
			'siteport' => '',


			'config' => array(),
			'setting' => array(),
			'member' => array(),
			'group' => array(),
			'cookie' => array(),
			'style' => array(),
			'cache' => array(),
			'session' => array(),
			'lang' => array(),
			'my_app' => array(),
			'my_userapp' => array(),


			'fid' => 0,
			'tid' => 0,
			'forum' => array(),
			'thread' => array(),
			'rssauth' => '',


			'home' => array(),
			'space' => array(),


			'block' => array(),
			'article' => array(),


			'action' => array(
				'action' => APPTYPEID,
				'fid' => 0,
				'tid' => 0,
			),


			'mobile' => '',


		);
		$_G['PHP_SELF'] = dhtmlspecialchars($this->_get_script_url());
		$_G['basescript'] = CURSCRIPT;
		$_G['basefilename'] = basename($_G['PHP_SELF']);
		$sitepath = substr($_G['PHP_SELF'], 0, strrpos($_G['PHP_SELF'], '/'));
		if(defined('IN_API')) {
			$sitepath = preg_replace("/\/api\/?.*?$/i", '', $sitepath);
		} elseif(defined('IN_ARCHIVER')) {
			$sitepath = preg_replace("/\/archiver/i", '', $sitepath);
		}
		$_G['siteurl'] = dhtmlspecialchars('http://'.$_SERVER['HTTP_HOST'].$sitepath.'/');


		$url = parse_url($_G['siteurl']);
		$_G['siteroot'] = isset($url['path']) ? $url['path'] : '';
		$_G['siteport'] = empty($_SERVER['SERVER_PORT']) || $_SERVER['SERVER_PORT'] == '80' ? '' : ':'.$_SERVER['SERVER_PORT'];


		if(defined('SUB_DIR')) {
			$_G['siteurl'] = str_replace(SUB_DIR, '/', $_G['siteurl']);
			$_G['siteroot'] = str_replace(SUB_DIR, '/', $_G['siteroot']);
		}


		$this->var = & $_G;
	}
}

眼神很亮地看到了$this->var = & $_G;

【私人例子：
 /
 course.php:
 $discuz = & discuz_core::instance(); /* & discuz_core:: ??????????*/
 $mod = !in_array($discuz->var['mod'], $modarray) ? 'list' : $discuz->var['mod'];
 看不懂~~于是下文：
 
/source/class/discuz/
discuz_application.php:
class discuz_application extends discuz_base
{
 
 static function &instance()

  {
 static $object;
 if(empty($object)) 

 {
 $object = new self();
 }
 return $object;
 }
 函数&instance创建了一个静态变量（变量？？），若他为空则new self()。应该是new了一个class discuz_application的对象。
 暂时理解为。。当前实例句柄。。。然后去找了forum.php,home.php。。。没有发现。
 应该是为了统一管理像mod这样的变量吧（猜测。mod是为了存储当前的mod（edit，list等等。））
 
 回到$this->var = & $_G;
 则$discuz->var['mod']等价于$_G['mod']
 
 于是又牵扯到了$_G['mod'] （烦死了有木有~！！！）
 在discuz_application.php中搜索$_G['mod']。
 
/source/class/discuz/
discuz_application.php:
class discuz_application extends discuz_base
{
 
 public function init()
  {
 if(!$this->initated)
  {
 $this->_init_db();
 $this->_init_setting();
 $this->_init_user();
 $this->_init_session();
 $this->_init_mobile();
 $this->_init_cron();
 $this->_init_misc();
 }
 $this->initated = true;
 }
 public function __construct()
 {  $this->_init_env();  $this->_init_config();  $this->_init_input();  $this->_init_output();  }
 private function _init_input() 
 {
 $this->var['mod'] = empty($_GET['mod']) ? '' : dhtmlspecialchars($_GET['mod']);
 }
}
推测，当new一个class discuz_application对象时。调用__constract()。就会创建一个$_G['mod']。。可能为空，可能有值。而当每次页面跳转打到course.php。都会对mod重新赋值。
于是再看course.php：
/
course.php:
define('CURMODULE', $mod);
$discuz->init();
看到define。。应该就是他了。'CURMODULE'是什么？？？再说吧。。。
discuz_application.php中也没有找到 $this->_init_setting();？？？再说吧。。。

】