Re: [squid-users] Reverse-Proxy/Cache for one backend webserver

Frank Helmschrott wrote:
> Hi all,
>
> i'm rather new to squid so sorry if some of my questions sound a bit
> dumb. I already read a lot about reverse proxy/caching with squid and
> i'm sure squid is the right thing for my project.
>
> My setup is a 2-server setup with one server with squid installed
> beeing the proxy-server for a dynamic website delivered from server 2
> using apache/php/mysql. The Website on server 2 is a news-style
> website. Therefore the content isn't too dynamic making not only
> graphics and css files cachable but also the news items itself.
>
> For testing purposes i setup a small script and some dns stuff so that
>
> dyn.testdomain.com resolves to the public ip of server 2
> stat.testdomain.com resolves to the public ip of server 1 (squid)
>
> The test script just contains a little php for the header (to set
> expire, modified and stuff) and an output of the actual time to let me
> see if it's fetched from server 2 or the cache.
>
> After setting up everything i found to be important the basic proxy
> stuff works apart from the caching and expiry stuff. It seems like
> squid is fetching the original content whenever i reload the browser.

As Henrik pointed out reload causes fresh content to be forced through
the proxy. Better just to set your browser non-caching and visit the
page several times.

> I've also already set refresh_pattern to match php files and override
> the expiry set in the script and ignore reloads but unfortunately this
> doesn't help. Here's what my squid conf looks like:
> (below you'll find the php script i use for testing)
>
> ---
> cache_mgr my_at_email.com
> cache_dir ufs /var/cache/squid 4096 16 256
> cache_mem 2048 MB
> collapsed_forwarding on
> minimum_expiry_time 120 seconds
> http_port 127.0.0.1:80 vhost vport
> cache_peer 127.0.0.2 parent 80 0 originserver default

By '2 servers' you mean you are simulating them yes? The two lines above
will only work within the local host.

>
> acl all src 0.0.0.0/0.0.0.0
> acl QUERY urlpath_regex ^/admin \?
>
> acl our_sites dstdomain .testdomain.com
> http_access allow our_sites
> no_cache allow QUERY

no_cache is obsolete. Allow is the default anyway. Best to just omit
that and the ACL setting up QUERY in the first place.

>
> acl manager proto cache_object
> acl localhost src 127.0.0.1/255.255.255.255
> http_access allow manager localhost
>
> cachemgr_passwd comet74 all
>
> via on
> header_access Via allow all
> header_access Age deny all
> header_access X-Cache deny all
>
> refresh_pattern -i \.jpg$ 120 90% 240 override-expire override-lastmod
> reload-into-ims ignore-reload
> refresh_pattern -i \.jpeg$ 120 90% 240 override-expire
> override-lastmod ignore-reload reload-into-ims
> refresh_pattern -i \.gif$ 120 90% 240 override-expire override-lastmod
> ignore-reload reload-into-ims
> refresh_pattern -i \.png$ 120 90% 240 override-expire override-lastmod
> ignore-reload reload-into-ims
> refresh_pattern -i \.swf$ 120 90% 240 override-expire override-lastmod
> ignore-reload reload-into-ims
> refresh_pattern -i \.flv$ 120 90% 240 override-expire override-lastmod
> ignore-reload reload-into-ims
> refresh_pattern -i \.js$ 10 90% 20 override-expire override-lastmod
> ignore-reload reload-into-ims
> refresh_pattern -i \.css$ 10 90% 20 override-expire override-lastmod
> ignore-reload reload-into-ims

It's really best to configure these age settings in the web server. That
way they will duplicate out around the net, not just in your squid.

>
> refresh_pattern -i \.php$ 10 90% 720 override-expire override-lastmod
> ignore-reload ignore-no-cache
>

So where are the default patterns that handle general objects without
expiry info?

> ---
>
> <?php
> //expire time in minutes
> $expire = 3;
>
> $exp_gmt = gmdate("D, d M Y H:i:s", time() + $expire * 60) ." GMT";
> $mod_gmt = gmdate("D, d M Y H:i:s", getlastmod()) ." GMT";
>
> // HTTP 1.0
> header("Expires: " . $exp_gmt);
> header("Last-Modified: " . $mod_gmt);
>
> // HTTP 1.1
> header("Cache-Control: public, max-age=" . $expire * 60);
> //header("Pragma: ");
> ?>
> <?php
>
> $i = 1;
>
> while ($i <= 3):
> echo $i++ . "<br />";
> endwhile;
>
> echo "miss at " . date('H:i:s');
> ?>
>
> Any help is appreciated.
>

Amos

-- 
Please use Squid 2.7.STABLE2 or 3.0.STABLE6