List Info

Thread: mod_disk_cache summarization




mod_disk_cache summarization
user name
2006-10-27 21:33:16
Niklas Edmundsson wrote:

> Different VHosts meaning different URLs/directories,
pointing to the 
> same files...

Hmm... Two thoughts come into my head over this one.

One way to approach this is to treat this as a general
problem of how do 
we stop people who download the same file from multiple
places (say 
different mirrors via proxy, or different URLs to the
backend like you 
have) from downloading multiple copies of the same file
hosted at 
different URLs.

Here you might have some kind of regex-like expression, like
*.iso, that 
says "all files whose names match this regex, are
considered the same 
file". A mechanism might have a small cache of
filenames that have 
matched the regex in the past, and that link to actual
cached entries in 
the cache.

This would need to be abstracted out into an existing hook
(or new one 
if necessary).

A second approach could involve the use of the Etags
associated with 
file responses, which in the case of files served off disk
(as I 
understand it) are generated based on inode number and
various other 
uniquely file specific information.

Therefore in theory two responses with the same Etag are
actually the 
same file, and if you've already cached a file with that
Etag, then the 
same Etag quick cache scenario described above could provide
a shortcut 
to the same file cached at a different URL.

Regards,
Graham
--
[1]

about | contact  Other archives ( Real Estate discussion Medical topics )