fast cache php / image du jour bing

Retour
$cache = '/tmp/imgoftheday.txt';
$nbsecondes = 3600;
if (!file_exists($cache) || (filemtime($cache) <= (time() - $nbsecondes )))
{
  $json = json_decode(file_get_contents('http://www.bing.com/HPImageArchive.aspx?format=js&idx=0&n=1&mkt=en-US'), true);
  $res = 'http://www.bing.com'.$json['images'][0]['url'];
  file_put_contents($cache, $res);
}
else
  $res = file_get_contents($cache);
echo $res;