Why do caching heuristics exclude 303?


I'm currently reading 'HTTP/1.1, part 6: Caching' [1] and stumbled in
' Calculating Heuristic Freshness' over the following:

'If no explicit expiration time is present in a stored response that
 has a status code of 200, 203, 206, 300, 301 or 410, a heuristic
 expiration time can be calculated.  Heuristics MUST NOT be used for
 other response status codes.'

Is there a deeper reason why 303 is not included in the heuristics?

Please forgive me if this came up already. I searched in the archive, but
failed to find an answer to this question.


[1] http://tools.ietf.org/html/draft-ietf-httpbis-p6-cache-08

Dr. Michael Hausenblas
LiDRC - Linked Data Research Centre
DERI - Digital Enterprise Research Institute
NUIG - National University of Ireland, Galway
Ireland, Europe
Tel. +353 91 495730

Received on Friday, 22 January 2010 16:43:52 UTC