code: def file_response(request, filepath, block=None, status_code=None,
                    content_type=None, encoding=None, cache_control=None):
      
      file_wrapper = request.get('wsgi.file_wrapper')
      if os.path.isfile(filepath):
          response = request.response
          info = os.stat(filepath)
          size = info[stat.ST_SIZE]
          modified = info[stat.ST_MTIME]
          header = request.get('HTTP_IF_MODIFIED_SINCE')
          if not was_modified_since(header, modified, size):
              response.status_code = 304
          else:
              if not content_type:
                  content_type, encoding = mimetypes.guess_type(filepath)
              file = open(filepath, 'rb')
              response.headers['content-length'] = str(size)
              response.content = file_wrapper(file, block)
              response.content_type = content_type
              response.encoding = encoding
              if status_code:
                  response.status_code = status_code
              else:
                  response.headers["Last-Modified"] = http_date(modified)
              if cache_control:
                  etag = digest('modified: %d - size: %d' % (modified, size))
                  cache_control(response.headers, etag=etag)
          return response
      raise Http404
docs: Utility for serving a local file
  
      Typical usage::
  
          from pulsar.apps import wsgi
  
          class MyRouter(wsgi.Router):
  
              def get(self, request):
                  return wsgi.file_response(request, "<filepath>")
  
      :param request: Wsgi request
      :param filepath: full path of file to serve
      :param block: Optional block size (default 1MB)
      :param status_code: Optional status code (default 200)
      :return: a :class:`~.WsgiResponse` object