Content-Range and Caching Proxies
Anselm Baird_Smith (abaird@www43.inria.fr)
Tue, 4 Mar 1997 14:58:51 +0100 (MET)
I am trying to add range support within my proxy following that
scheme: the proxy gets a document, and caches it in a local
file. Latter on a request comes in for that document (which is still
fresh according to both the request and the cache entry) with a
range specification. In that case the proxy will (should/could ?)
handle the range request.
My concerns are:
- Should the proxy emit an 'Accept-Range' header when serving the
cached entry (since now that it has entered the cache, the cached
resource will handle ranges)
- The spec says (13.5.2) that I can implement that only if the
Cache-Control directive 'no-transform' has not been set by the
origin server, I am not sure I understand the rationale. In
particular it seems to me that this case is (potentially) much less
"harmfull" than if I were to transform gif images to jpegs - I mean
transform the entity - and the client will not be able to
distinguish between these two cases since they use the same
warning).
[that same remark applies to the case where you want to use byte
ranges in the proxy (instead of supporting them) ?]
I guess I miss something, though,
Anselm.