Record a practical PHP caching class_PHP tutorial

Caching is widely used in actual use, which can reduce access to the server database and improve operating speed. At present, many CMS content management systems frequently use caching mechanisms to improve the efficiency of system operation. The following is a well-written cache class. You can refer to the cache mechanism and writing method.

cache.php code is as follows:

<?  
/* 
用户需要事先定义的常量： 
_CachePath_        模板缓存路径 
_CacheEnable_        自动缓存机制是否开启，未定义或为空，表示关闭自动缓存机制 
_ReCacheTime_        自动重新缓存间隔时间，单位为秒，未定义或为空，表示关闭自动重新缓存 
*/  
  
class cache 
{
	var $cachefile;  
	var $cachefilevar;  
  
	function cache() 
	{  
        //生成当前页的Cache组文件名 $this->cachefilevar 及文件名 $this->cachefile  
        //动态页的参数不同对应的Cache文件也不同，但是每一个动态页的所有Cache文件都有相同的文件名，只是扩展名不同  
        $s=array(".","/");$r=array("_","");  
        $this->cachefilevar=str_replace($s,$r,$_SERVER["SCRIPT_NAME"])."_".$_GET[_ActionVar_];  
        $this->cachefile=$this->cachefilevar.".".md5($_SERVER["REQUEST_URI"]);  
	}  
  
	//删除当前页/模块的缓存  
	function delete() 
	{  
        //删除当前页的缓存  
        $d = dir(_CachePath_);  
        $strlen=strlen($this->cachefilevar);  
        //返回当前页的所有Cache文件组  
        while (false !== ($entry = $d->read())) 
		{  
       		if (substr($entry,0,$strlen)==$this->cachefilevar) 
			{  
           		if (!unlink(_CachePath_."/".$entry)) {echo "Cache目录无法写入";exit;}  
         	}  
     	}  
	}  
  
	//判断是否已Cache过，以及是否需要Cache  
	function check() 
	{  
        //如果设置了缓存更新间隔时间 _ReCacheTime_  
        if (_ReCacheTime_+0>0)
		{  
       		//返回当前页Cache的最后更新时间  
         	$var=@file(_CachePath_."/".$this->cachefilevar);$var=$var[0];  
         	//如果更新时间超出更新间隔时间则删除Cache文件  
       		if (time()-$var>_ReCacheTime_) 
			{  
           		$this->delete();$ischage=true;  
         	}  
  		}  
        //返回当前页的Cache  
        $file=_CachePath_."/".$this->cachefile;  
        //判断当前页Cache是否存在 且 Cache功能是否开启  
        return (file_exists($file) and _CacheEnable_ and !$ischange);  
	}  
  
	//读取Cache  
	function read() 
	{  
    	//返回当前页的Cache  
        $file=_CachePath_."/".$this->cachefile;  
        //读取Cache文件的内容  
        if (_CacheEnable_) return readfile($file);  
        else return false;  
	}  
  
	//生成Cache  
	function write($output) 
	{  
        //返回当前页的Cache  
        $file=_CachePath_."/".$this->cachefile;  
        //如果Cache功能开启  
        if (_CacheEnable_) 
		{  
          	//把输出的内容写入Cache文件  
       		$fp=@fopen($file,'w');  
           	if (!@fputs($fp,$output)) {echo "模板Cache写入失败";exit;}  
           	@fclose($fp);  
           	//如果设置了缓存更新间隔时间 _ReCacheTime_  
          	if (_ReCacheTime_+0>0) 
			{  
               	//更新当前页Cache的最后更新时间  
             	$file=_CachePath_."/".$this->cachefilevar;  
               	$fp=@fopen($file,'w');  
              	if (!@fwrite($fp,time())) {echo "Cache目录无法写入";exit;}  
             	@fclose($fp);  
          	}  
   		}  
	}  
}  
?>

Usage of class:

<?php  
	define("_CachePath_","./cache/");  
	define("_CacheEnable_","1");  
	define("_ReCacheTime_","43200");  
	include('cache.php');  
	$cache=new cache();  
	if ($cache->check()) 
	{  
		$template=$cache->read();  
	}
	else 
	{  
 		ob_start();  
     	ob_implicit_flush(0);  
?>  
	页面内容。。。。  
<?php  
		$template = ob_get_contents();  
		$cache->write($template);  
	}  
?>  

http://www.bkjia.com/PHPjc/752495.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/752495.htmlTechArticleCache is widely used in actual use, which can reduce access to the server database and improve operating speed. At present, many CMS content management systems frequently use caching mechanisms to improve the system...