code: function FilesystemHandler(req, res, next, urlAlias, localPath, local = false) {
              const parsedUrl = url.parse(req.url);
              if (!parsedUrl.pathname.startsWith(urlAlias)) {
                  return next();
              }
  
              const bareUrl = parsedUrl.pathname.substr(urlAlias.length);
  
              let filePath;
              if (localPath) {
                  filePath = path.join(localPath, decodeURIComponent(bareUrl));
                  if (filePath.toLowerCase().lastIndexOf(localPath.toLowerCase(), 0) !== 0) {
                      return respondWithCode(res, 400, 'Wrong path.');
                  }
              } else {
                  filePath = decodeURIComponent(bareUrl);
              }
  
              if (fs.existsSync(filePath)) {
                  return local ?
                      createStreamProtocolResponse(filePath, res, () => {
                      }) :
                      send(req, encodeURIComponent(filePath)).pipe(res);
              }
              return local ? res.setStatusCode(404) : respondWithCode(res, 404, 'File does not exist.');
          }
docs: Provides files from the filesystem on a specified url alias.
  
  @param {Object} req        - request object
  @param {Object} res        - response object
  @param {Function} next     - called on handler miss
  @param {string} urlAlias   - url alias on which to serve the files
  @param {string=} localPath - serve files only from this path
  @param {boolean} local - local mode