RE: [users@httpd] Apache reverse and caching proxy

[Wim.Van.Leuven@xxxxxx]

Hello Axel-Stéphane,

If I can follow what you are trying
to tell me, I should add the "expiresactive on" directive on
the source server instead of the caching server?

Axel-Stéphane  SMORGRAV <Axel-Stephane.SMORGRAV@xxxxxxxxxxxxxx>

12/01/2006 15:12

Please respond to
users@xxxxxxxxxxxxxxxx

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Subject	RE: [users@httpd] Apache reverse and caching proxy

The mod_expires that you activate with "ExpiresActive
On" will add an Expires header to the responses sent to the client.
It does nothing for Apache cache expiration. It does however have an effect
on the expiration of downstream caches, in your case probably on the User
Agent cache.

For cache expiration you should use the CacheDefaultExpire directive.  I
believe mod_cache will make a conditional request for the resource when
the cache entry gets stale. 

If you set CacheDefaultExpires to a low value, mod_cache will frequently
try to refresh the cache. 

CacheDefaultExpires affects only responses that do not contain an explicit
expiry date.
 
-ascs
________________________________

From: Wim.Van.Leuven@xxxxxx [mailto:Wim.Van.Leuven@xxxxxx] 
Sent: Thursday, January 12, 2006 3:02 PM
To: users@xxxxxxxxxxxxxxxx
Subject: [users@httpd] Apache reverse and caching proxy



Hello all, 

I'm retrying my configuration for a caching proxy server which flushes
the cache on the modification time of the files. However, It doesn't seem
to work anymore. The files get cached but are not refreshed on a touch
of the file on the source server. 

Not sure what I changed that it doesn't work anymore. As far as I'm concerned,
I do nothing more then setup an apache server to serve static files from
disk in an ordinary manner. Next I put a proxy server in front. The configuration
of the proxy can be found at the end. 

When inspecting the debug logs and the http headers, all files get cached
at the proxy. However when I change the modification time of the files
on the source servers, the cache doesn't get updated. Thus still serving
the old version of the file. 

As a matter a fact, once a file is cached, the source server is never accessed
anymore to verify the correctness of the cache against the remote instances.

Does anybody have a clue about which sublety I'm missing here? 

Thanks beforehand! 
Wim Van Leuven 

________________________________ 

... 
ExpiresActive On 
ExpiresDefault "modification" 
... 
ProxyRequests Off 

<Proxy *> 
    Order deny,allow 
    Allow from all 
</Proxy> 

ProxyPass / http://srcsvr.ldc.local/ 
ProxyPassReverse / http://srcsvr.ldc.local/ 

# Cache configuration 
<IfModule mod_cache.c> 
    LoadModule disk_cache_module modules/mod_disk_cache.so 
    <IfModule mod_disk_cache.c> 
            CacheRoot "C:/Program Files/Apache
Group/Apache2/cache" 
            CacheSize 256 
            CacheEnable disk / 
            CacheDirLevels 5 
            CacheDirLength 3 
            CacheIgnoreCacheControl Off 
    </IfModule> 
    
    #LoadModule mem_cache_module modules/mod_mem_cache.so 
    <IfModule mod_mem_cache.c> 
        CacheEnable mem / 
        MCacheSize 4096 
        MCacheMaxObjectCount 100 
        MCacheMinObjectSize 1 
        MCacheMaxObjectSize 2048 
    </IfModule>     
</IfModule> 


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