/**
* Look up the cache file and if it exists and hasn't expired return the
* path to the cache file.
*
* @param string $header
* The raw request header
* @return string|bool
*/
protected function get_cache($header)
{
$key = $this->create_cache_key($header);
$file = Net::tmpdir() . "/{$key}.cache";
if (file_exists($file)) {
$mtime = filemtime($file);
if (time() < $mtime + $this->cache) {
$this->cache = 0;
return $file;
} else {
unlink($file);
}
}
return false;
}
