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php Cache 类实例详解

小云云

Lepaskan： 2023-03-21 07:26:01

asal

12244 orang telah melayarinya

本文主要和大家分享php Cache 类实例详解，希望能帮助大家更好理解cache的使用方法。

推荐手册：php完全自学手册

1、实例化

$cache = new Cache();

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2、设置缓存时间和缓存目录

$cache = new Cache(60, &#39;/any_other_path/&#39;);

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第一个参数是缓存秒数，第二个参数是缓存路径，根据需要配置。
默认情况下，缓存时间是 3600 秒，缓存目录是 cache/

3、读取缓存

$value = $cache->get(&#39;data_key&#39;);

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4、写入缓存

$value = $cache->put(&#39;data_key&#39;, &#39;data_value&#39;);

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完整实例：

$cache = new Cache();

//从缓存从读取键值 $key 的数据
$values = $cache->get($key);

//如果没有缓存数据
if ($values == false) {
	//insert code here...
	//写入键值 $key 的数据
	$cache->put($key, $values);
} else {
	//insert code here...
}

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<?php
class Cache {
	private $cache_path;//path for the cache
	private $cache_expire;//seconds that the cache expires

	//cache constructor, optional expiring time and cache path
	public function Cache($exp_time=3600,$path="cache/"){
		$this->cache_expire=$exp_time;
		$this->cache_path=$path;
	}

	//returns the filename for the cache
	private function fileName($key){
		return $this->cache_path.md5($key);
	}

	//creates new cache files with the given data, $key== name of the cache, data the info/values to store
	public function put($key, $data){
		$values = serialize($data);
		$filename = $this->fileName($key);
		$file = fopen($filename, &#39;w&#39;);
	    if ($file){//able to create the file
	        fwrite($file, $values);
	        fclose($file);
	    }
	    else return false;
	}

	//returns cache for the given key
	public function get($key){
		$filename = $this->fileName($key);
		if (!file_exists($filename) || !is_readable($filename)){//can&#39;t read the cache
			return false;
		}
		if ( time() < (filemtime($filename) + $this->cache_expire) ) {//cache for the key not expired
			$file = fopen($filename, "r");// read data file
	        if ($file){//able to open the file
	            $data = fread($file, filesize($filename));
	            fclose($file);
	            return unserialize($data);//return the values
	        }
	        else return false;
		}
		else return false;//was expired you need to create new
 	}
}
?>

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