The issue:
html type pages (think objects in zope) cached in varnish, were not
purged successfully with zope/plone/cachefu purging methods.
Images were purged. but html content was not.
Given we depend on caching pages in accelerator/zope/plone this is a
showstopper. (e.g. we use this: cache-in-proxy-1-hour for (most) html
content)
In order to make purging work, I had to normalize or unset a couple
http.req attributes. This is what I came up with.
The 'working' solution:
sub vcl_recv {
...
if (req.http.Accept-Encoding) { /* lifted from varnish site */
if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg)$") {
# No point in compressing these
remove req.http.Accept-Encoding;
} elsif (req.http.Accept-Encoding ~ "gzip") {
set req.http.Accept-Encoding = "gzip";
} elsif (req.http.Accept-Encoding ~ "deflate") {
set req.http.Accept-Encoding = "deflate";
} else {
# unkown algorithm
remove req.http.Accept-Encoding;
}
}
unset req.http.Accept-Language; /* is this DANGEROUS? */
unset req.http.user-agent;
set req.http.host = "my.cashmoney.com";
...
}
Based on what I have read, unsetting these attributes help keep
multiple cache objects to a minimum.
Which is the reasoning behind normalizing the Accept-Encoding per http://varnish-cache.org/wiki/FAQ/Compression
So, I guess I have 2 questions:
1) Given the site is only served in english, is there a danger of
serving up the wrong hit for a browser with a different Accept-Language?
2) Will I still get purge misses for objects cached by some browsers,
like ones presenting deflate instead of gzip in the header?
Thanks,
Rob