simple cache php

end_cache.php

<?php

if(!$frontCache->isCached()) {
$frontCache->cachePage();
}

FrontCache.php

<?php
class FrontCache
{
	private $page;
	private $dir;
	private $expirationTime;
	
	public function __construct($page, $dir='cache', $expirationTime = 86400)
	{
		$this->page = $page;
		$this->dir = $dir;
		$expirationTime = 86400;
	}
        
        public function startCaching()
        {
		ob_start();
        }

	public function cachePage()
	{
		$cachedPage = $this->getCachedPage()
<<<EOF
				</div>
			</div>

		<script type = "text/javascript">
			setSelectSku(1);
		</script>
EOF;
			$fp = @fopen($cachedPage,'w');
			fwrite($fp, ob_get_contents());
			fclose();
			ob_end_flush();  
	
	}
	
	public function outputCachedPage() {
		if($this->isCached()) {
			$cachedPage = $this->getCachedPage();
			@readfile($cachedPage);
		    exit();
		}
	}
	
	public function isCached()
	{
		$cachedPage = $this->getChachedPage();
		if (@file_exists($cachedPage)) {
		    $cachelast = @filemtime($cachefile);
		} else {
		    $cachelast = 0;
		}
		@clearstatcache();
		// Mostramos el archivo si aun no vence
		if (time() - $cachetime <$cachelast) {
		    return true
		}
		else {
			return false;
		}
	}
	
	public function getCachedPage()
	{
		return $this->dir.md5($this->page).'.cache';
	}

}

start_cache.php

<?php
$page = $_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
$frontCache = new FrontCache($page);

if($frontCache->isCached()) {
	$frontCache->outputCachedPage();
}
else {
	$frontCache->startCaching();
}