Content cache class

Posted under Article Development PHP on Sunday, 12 July 2009 by rueben

This class can be used to cache content in files.

It checks whether a given cache file exists. If it exists and is not expired, the class returns
the cache file contents. If it has expired, the class removes the cache file.

If the cache file does not exist, the class can create a new cache file with from fresh content.

The path of the directory where the cache files are stored is configurable.

<?php

/*------------------------------------------------------------------------------------------

CONTENT CACHER CLASS
--------------------
Dev By Leon
2007.10.12.
Budapest

copyright 2007 LeonCreatives - gabor szilagyi
Licenced under the GNU Lesser General Public License (Version 3)
http://www.gnu.org/licenses/lgpl.html

Usage:
------
$cache = new contentCache($_SERVER);
$cache->makeExpiration();
if ($cache->status==true) {
  echo $cache->content;
}
else {
  //Create any content to cache!
  $html="<h1>foo</h1>";
  $cache->makeCache($html);
  echo $html;
}

------------------------------------------------------------------------------------------*/

//Class definition
class contentCache {

  //Url witch contains information about requested page
  public $url = "";

  //Method type of request
  public $method="";

  //Path to cache files
  public $path="cache/";

  //Cache contents
  public $content="";

  //Result status of cached contents
  public $status=false;

  //Data array to store the $_SERVER assoc.
  private $DATA = null;

  //Prepared filename of the cache file
  private $fname="";

  //Last modification timestamp of the cache file
  private $last_mod_time=0;

  //Timestamp of now
  private $now = 0;

  //Used for to calculate the interval of cache time

//www.cpworld2000.com
  private $exp_min = 0;

  //Expiration time limit
  private $exp_max = 3600;

  //Constructor and main method
  public function contentCache($data) {
    if (isset($data)) {
      $this->DATA=$data;
      $this->prepareData();
      $result = $this->checkContent();
    }
    else {
      throw new Exception("One of the requested parameters is empty...");
    }
  }

  private function prepareData() {
    if ($this->DATA['REQUEST_URI']) {
      $this->url=$this->DATA['REQUEST_URI'];

//OSPHP.COm.CN
      $this->url=str_replace("/","_",$this->url);
      $this->url=str_replace("?","_",$this->url);
      $this->url=str_replace("=","_",$this->url);
      $this->url=str_replace("&","_",$this->url);

      if ($this->url!="") {
        $this->fname=$this->url.".cache";
      }
    }
  }

  private function checkContent() {
    if ($this->fname && is_file($this->path.$this->fname)) {
      $this->content = file_get_contents($this->path.$this->fname); //PHP开源代码
      $this->status=true;
    }
    else {
      $this->content="";
      $this->status=false;
    }
  }

  public function makeCache($content="") {
    if ($content) {
      file_put_contents($this->path.$this->fname,$content);
    }
    else {
      throw new Exception("No content to cache...");
    }

    return true;
  }

  public function makeExpiration() {
    $this->last_mod_time = filemtime($this->path.$this->fname); //PHP开源代码
    $this->now = time();
    $this->exp_min=$this->now-$this->last_mod_time;

    if ($this->exp_min>$this->exp_max) {
      unlink($this->path.$this->fname);
    }

    return true;
  }
//End of the cache class

}
?>