Auto cache file to get new data

<?php
 $present = time();
 $cache_url = "http://..."; // URL contains data refresh each day
 $cfile = "cache.txt";
 if (file_exists($cfile)) {
  $handle = fopen($cfile, "r");
  $buffer = fgets($handle, 256); // 256 is enough to get data from first line in cache file
  $a = split("\r\n", $buffer);
  // read cache time at a first line in cache file
  $cachetime = $a[0];
  fclose($handle);
  if ($cachetime + 24 * 60 * 60 < $present) {// recache after 1 day
   echo "Cache File Will Be Updated<hr>";
   $source = file_get_contents($cache_url);
   // save cache time at a first line in cache file
   file_put_contents($cfile, $present . "\r\n" . $source);
  } else {// cache file is still new
   echo "Load From Cached File (cached at " . date("H:i:s d-m-Y", $cachetime) . ")<hr>";
   $source = file_get_contents("cache.txt");
  }
 } else {
  $source = file_get_contents($cache_url);
  file_put_contents($cfile, $present . "\r\n" . $source);
 }
 
 // processing cache data
?>