def temporary_url(expires_at = Time.now + 3600)
      url = URI.escape("#{protocol}#{host(true)}/#{path_prefix}#{key}")
      signature = Signature.generate_temporary_url_signature(:bucket => name,
                                                             :resource => key,
                                                             :expires_at => expires_at,
                                                             :secret_access_key => secret_access_key)

      "#{url}?SNDAAccessKeyId=#{access_key_id}&Expires=#{expires_at.to_i.to_s}&Signature=#{signature}"
    end
def temporary_url(expires_at = Time.now + 3600)
      url = URI.escape("#{protocol}#{host(true)}/#{path_prefix}#{key}")
      signature = Signature.generate_temporary_url_signature(:bucket => name,
                                                             :resource => key,
                                                             :expires_at => expires_at,
                                                             :secret_access_key => secret_access_key)

      "#{url}?SNDAAccessKeyId=#{access_key_id}&Expires=#{expires_at.to_i.to_s}&Signature=#{signature}"
    end
Returns a temporary url to the object that expires on the
 timestamp given. Defaults to 5min expire time.