php simple cache

<?php
function bacaHTML($url){
...........
}

function getFromCache($url){
  if (!file_exists("wincache")) {
    mkdir("wincache");
  }
  $cache_file = "wincache/_jadwal.txt";
  // cache for 61 minutes
  $file = "";
  if (file_exists($cache_file) && (filemtime($cache_file) > (time() - 60 * 61 ))) {
    $file = file_get_contents($cache_file);
  }
  else{
    $file = bacaHTML($url);
    file_put_contents($cache_file, $file, LOCK_EX);
  }
  return $file;
}

$kodeHTML = getFromCache('http://................');
............
?>