Сейчас у меня вот:


location ~ ^/preview/([cira])/(.+) {
set $oper $1;

set $remn $2;

# Proxy
proxy_pass http://127.0.0.1:81/$oper/$remn;
proxy_intercept_errors on;
error_page 404 = /preview/404;

proxy_store on;
proxy_store_access user:rw group:rw all:r;
proxy_temp_path /temp;
proxy_set_header If-Modified-Since "";

expires max;

root /runtime/cache;
}