wrappers.py 文件源码

def _process_range_request(self, environ, complete_length=None, accept_ranges=None):
        """Handle Range Request related headers (RFC7233).  If `Accept-Ranges`
        header is valid, and Range Request is processable, we set the headers
        as described by the RFC, and wrap the underlying response in a
        RangeWrapper.

        Returns ``True`` if Range Request can be fulfilled, ``False`` otherwise.

        :raises: :class:`~werkzeug.exceptions.RequestedRangeNotSatisfiable`
                 if `Range` header could not be parsed or satisfied.
        """
        from werkzeug.exceptions import RequestedRangeNotSatisfiable
        if accept_ranges is None:
            return False
        self.headers['Accept-Ranges'] = accept_ranges
        if not self._is_range_request_processable(environ) or complete_length is None:
            return False
        parsed_range = parse_range_header(environ.get('HTTP_RANGE'))
        if parsed_range is None:
            raise RequestedRangeNotSatisfiable(complete_length)
        range_tuple = parsed_range.range_for_length(complete_length)
        content_range_header = parsed_range.to_content_range_header(complete_length)
        if range_tuple is None or content_range_header is None:
            raise RequestedRangeNotSatisfiable(complete_length)
        content_length = range_tuple[1] - range_tuple[0]
        # Be sure not to send 206 response
        # if requested range is the full content.
        if content_length != complete_length:
            self.headers['Content-Length'] = content_length
            self.content_range = content_range_header
            self.status_code = 206
            self._wrap_response(range_tuple[0], content_length)
            return True
        return False