[Http-crcsync] http-sync standard
tridge at samba.org
tridge at samba.org
Sun Apr 5 20:11:07 EDT 2009
Hi Toby,
> This is transmitted in two forms. One is an SHA1 hash of the complete chached
> file, and the other is a set of block hashes.
...
> Content-Hash:
> This will be an sha1 hash of the entire cached body, and will allow the server
> to transmit deltas based on its knowledge of past versions of the page.
How do you imagine that this hash would be used? I don't think it is
practical to think that servers would keep a record of all the dynamic
pages they have been served out, and for static pages I think the
normal cache tag mechanisms already work well.
I think a SHA1 or similar of the servers generated page is really
worthwhile, but a whole file hash of what the client has in cache
doesn't gain anything that I can see.
btw, I also wonder if you've seen this:
http://www.ietf.org/rfc/rfc3229.txt
That is the result of earlier efforts to standardise delta encoding in
HTTP. I was a little bit involved in that effort, although it
concentrated on storing old copies on the server, which I wasn't
interested in.
Still, it should provide some very useful background to the current
effort.
Cheers, Tridge
More information about the Http-crcsync
mailing list