code: public static function setCache($name, $value = '', $expired = 3600)
      {
          $cache_file = self::getCacheName($name);
          $content = serialize(['name' => $name, 'value' => $value, 'expired' => time() + intval($expired)]);
          if (!file_put_contents($cache_file, $content)) {
              throw new Exception('local cache error.', 500);
          }
      }
docs: 缓存配置与存储
  @param string $name 缓存名称
  @param string $value 缓存内容
  @param int $expired 缓存时间(0表示永久缓存)
  @throws Exception