code: public function getUrl($name, $expires = NULL)
  	{
  		return $this->getClient()->getObjectUrl($this->bucket, $name, $expires);
  	}
docs: Returns the url of the file or empty string if the file does not exists.
  @param string $name the key name of the file to access
  @param mixed $expires The time at which the URL should expire
  @return string