Class BaseHeuristic

cachecontrol/heuristics.py:27–57

class BaseHeuristic:
    def warning(self, response: HTTPResponse) -> str | None:
        """
        Return a valid 1xx warning header value describing the cache
        adjustments.

        The response is provided too allow warnings like 113
        http://tools.ietf.org/html/rfc7234#section-5.5.4 where we need
        to explicitly say response is over 24 hours old.
        """
        return '110 - "Response is Stale"'

    def update_headers(self, response: HTTPResponse) -> dict[str, str]:
        """Update the response headers with any new headers.

        NOTE: This SHOULD always include some Warning header to
              signify that the response was cached by the client, not
              by way of the provided headers.
        """
        return {}

    def apply(self, response: HTTPResponse) -> HTTPResponse:
        updated_headers = self.update_headers(response)

        if updated_headers:
            response.headers.update(updated_headers)
            warning_header_value = self.warning(response)
            if warning_header_value is not None:
                response.headers.update({"Warning": warning_header_value})

        return response


class OneDayCache(BaseHeuristic):