Easy php caching from http://wern-ancheta.com/blog/2014/01/26/getting-started-with-caching-in-php/

easy-php-cache.php

<?php
$file = sys_get_temp_dir().'/phpcache.' . basename($_SERVER['SCRIPT_NAME']); //location of cache file
$current_time = time();
$cache_last_modified = filemtime($file); //time when the cache file was last modified

if(file_exists($file) && ($current_time < strtotime('+1 day', $cache_last_modified))){ //check if cache file exists and hasn't expired yet
  include($file); //include cache file
}else{
  ob_start(); //start output buffering
?>
  <h1>Hello World!</h1>
  
<?php
  /*
 some code accessing the database
 for some data here
 */

  /*
 probably some complex computations here
 */

  $fp = fopen($file, 'w'); //open cache file
  fwrite($fp, ob_get_contents()); //create new cache file
  fclose($fp); //close cache file
  ob_end_flush(); //flush output buffered
}
?>