// Get an AmazonResultSet either from cache or a live query
// If a live query add it to the cache
function getARS($type, $parameters)
{
  $cache = cached($type, $parameters);
  if($cache)  // if found in cache
  {
    return  $cache;
  }
  else
  {
    $ars = new AmazonResultSet;
    if($type == 'asin')
      $ars->ASINSearch(padASIN($parameters['asin']), $parameters['mode']);
    if($type == 'browse')                   
      $ars->browseNodeSearch($parameters['browsenode'], 
$parameters['page'], $parameters['mode']);
    if($type == 'search')
      $ars->keywordSearch($parameters['search'], $parameters['page'],
                          $parameters['mode']);
    cache($type, $parameters, $ars);
  }
  return $ars;
}