On 13 Aug 2010, at 8:25 PM, Bryan McQuade wrote:
In looking at the source for mod_deflate:
http://www.google.com/codesearch/p?hl=en#lfs-jRjrQ3s/trunk/modules/
filters/mod_deflate.c&l=524
It appears to insert Vary Accept-Encoding header into every candidate
response by default, which is what you would expect.
But the instructions here: http://httpd.apache.org/docs/2.0/mod/mod_deflate.html
suggest adding a line to manually add Vary Accept-Encoding to
responses:
# Make sure proxies don't deliver the wrong content
Header append Vary User-Agent env=!dont-vary
Is this "Header append Vary User-Agent env=!dont-vary" necessary or
does mod_deflate now add the Vary Accept-Encoding header by default?
One extra thing on varying on the useragent string - we (very large UK
based media website) recently sampled about a week's worth of User-
Agent strings, and came up with roughly 1 million unique strings,
which in the process renders caching meaningless.
Ideally people shouldn't be varying on useragent, and we shouldn't be
suggesting people to do so in any documentation if we can avoid it.
Regards,
Graham
--
