Hi everyone,
I’ve been struggling with this for some time now trying to drop varnish
in favor for nginx.
Server: nginx/0.8.54
quick peek on problem - SSI on; proxy_cache_bypass caches backend
response as regular html page with HTTP/1.1 200 OK inside, so next fetch
from cache will return to client a page with SSI tags inside
(unprocessed).
And now the full configuration if the problem is still not clear.
My goal: force refresh of item in cache
Item has SSI tags inside which I would like to be processed (this is
obvious)
So far I’ve found that there’s no way of refreshing cache other than
deleting a file on hdd (which could lead to strange problems in my
opinion) or using proxy_cache_bypass. Bypass goes right to backend and
the response is cached, but with ssi on it’s cached wrong.
Configuration:
- debian6-32 (running nginx 0.8.54)
- bypass will be used when ‘Secret’ header is set
- backend has two files - index.php and footer.php
Step 1) first fetch (without bypass) returns this:
[20:45:01] debian6-32:~# printf "GET /num/5 HTTP/1.0\r\nHost:
debian6-32\r\n\r\n" | nc.traditional debian6-32 80 | grep '>'
>>>> FOOTER 08:46:05
>>>> INDEX 08:46:05
[20:45:08] debian6-32:~# printf "GET /num/5 HTTP/1.0\r\nHost:
debian6-32\\r\n\r\n" | nc.traditional debian6-32 80 | grep '>'
>>>> FOOTER 08:46:05
>>>> INDEX 08:46:05We can see that cache and SSI works fine (footer line is produced by
footer.php) and the whole page is cached
Step 2) let’s refresh cache using secret header
[20:45:16] ponury@eva:~ $ printf "GET /num/5 HTTP/1.0\r\nHost:
debian6-32\r\nSecret: 1\r\n\r\n" | nc.traditional debian6-32 80 | grep
'>>'
>>>> FOOTER 08:47:09
>>>> INDEX 08:47:09
[20:45:18] ponury@eva:~ $ printf "GET /num/5 HTTP/1.0\r\nHost:
debian6-32\r\nSecret: 1\r\n\r\n" | nc.traditional debian6-32 80 | grep
'>>'
>>>> FOOTER 08:47:11
>>>> INDEX 08:47:11
[20:45:20] ponury@eva:~ $Also bypass works great each time backend is being hit.
Step 3) fetch that page without bypass:
[20:45:11] debian6-32:~# printf "GET /num/5 HTTP/1.0\r\nHost:
debian6-32\r\nCookie: refresh=1\r\n\r\n" | nc.traditional debian6-32 80
| grep '>'
<!--# include file="/footer.php" -->
>>>> INDEX 08:47:11
[20:45:23] debian6-32:~#And here it is… clients receives unprocessed ssi header. The good news
is - its fresh. Bad news - it shouldn’t happen.
My current nginx config:
[code]
location / {
ssi on;
proxy_cache my-cache;
proxy_cache_valid 200 302 1m;
if ($remote_addr ~* "192.168.0.128") {
set $is_backend 1;
}
proxy_cache_bypass $is_backend $http_secret;
proxy_pass http://192.168.0.128$uri$is_args$args;
}
[/code]
So, is there something I’m missing or this just can’t be done?
Thank you in advance for any help.
Posted at Nginx Forum: