/**
* Get a random favorite photo from a Flickr user.
*
* @param string $userEmail Email address of a Flickr user
* @return object Phlickr_Photo
*/
function getRandomFavoritePhoto($userEmail)
{
$api = new Phlickr_Api(FLICKR_API_KEY, FLICKR_API_SECRET);
// load a saved cache file if it exists, set the expiration limit to a week.
$api->setCache(Phlickr_Cache::createFrom(CACHE_FILE, 60 * 60 * 24 * 7));
// select a random favorite photo
$user = Phlickr_User::findByEmail($api, $userEmail);
$favlist = $user->getFavoritePhotoList();
$photo = $favlist->getRandomPhoto();
assert(!is_null($photo));
// serialize and save the cache file
$api->getCache()->saveAs(CACHE_FILE);
return $photo;
}
