proxy_cache doesn't return headers

[Maxim Dounin]

Hello!

On Thu, Mar 03, 2011 at 05:23:45AM -0500, Alexander Zuban wrote:

> Hello,
> 
> We have quite busy phpbb based forum. I found that it is quite heavy
> loaded with bots(Google, AdSense, Yahoo. It seems that AdSense bot
> duplicate every user's request). I have added confuguration to cache all
> dynamic requests and return them to bots only(see config below). But I
> faced strange issue, when page returned from cache - nginx doesn't pass
> any headers back.
> 
> So questions are:  
>  * Are there anything bad that response considered as http 0.9?
>  * Is it possible configure it to return headers in case when page was
> returned from cache so response will be considered as 1.1?
>  * It seems that cache refreshed evertime when page was hit by user(not
> bot). Is it possible to configure it not to refresh it till it is
> valid(72h in config). To not produce not necessary IO. 

[...]

>                 proxy_cache_bypass $crawlernocache;

You are using proxy_cache_bypass without identical proxy_no_cache, 
it's known to have problems (and that's why you see http 0.9 
replies).  You have to write something like

                  proxy_cache_bypass $crawlernocache;
                  proxy_no_cache $crawlernocache;

instead.  This way a) http 0.9 problem will be fixed and b) normal 
users hits won't touch cache at all.

Maxim Dounin