Lighttpd

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#!rst ======================
Web Accelerating Cache ======================

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Module: mod_cache
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.. meta::
:keywords: lighttpd, cache, squid, web cache

.. contents:: Table of Contents

Description ===========
mod_cache provides a shared web cache for mod_proxy and uses a configuration similar to Squid Cache. mod_cache has several key benefits:

• Simple: mod_cache sets lighttpd flags between request handling stages. The request is then handled by mod_staticfile, mod_proxy, or other modules.
• Robust: mod_cache stores caches to the filesystem rather than to memory in order to avoid memory leaks/exhaustion.
• Fast: Lighttpd uses the Sendfile system call, which writes the file to the network interface directly.
• Powerful: mod_cache can be used in conjunction with other lighttpd plugins (except mod_deflate). For example; using mod_compress to compress cached files, using mod_access/mod_trigger_b4_dl to implement anti-hot-link restrictions, or using mod_flv_streaming to do native flv file streaming.

With the shared web cache, mox_proxy is able to deliver content from the local cache without having to re-download bulky files, thus simultaneously increasing the speed from the user's perspective while reducing up-stream bandwidth.

Installation ============
This module is a 3rd party module and is not included in the official distribution. You need to download it from here: * For lighttpd 1.4.13: [http://www.linux.com.cn/modcache/lighttpd-1.4.13.mod_cache.v1.2.patch] * For lighttpd 1.5.0.r1605: [http://www.linux.com.cn/modcache/lighttpd-1.5.0.r1605.modcache.v.1.3.2.patch]

The PCRE library is needed to build mod_cache.

Options =======
See [http://www.linux.com.cn/modcache/]

cache.bases
directory arrays which want to save cache files.

e.g.: ::

cache.bases=("/data/cache", "/data2/cache")

Default: not set

cache.enable
enable or disable mod_cache.

e.g.: ::

cache.enable = "disable" 
    $HTTP["host"] == "video.example.org" {
      cache.enable = "enable" 
    }

Default: enable

cache.domains
domain pcre regex arrays which mod_cache will cache.

e.g.: ::

cache.domains = ("mydomain.com$")

Default: not set (means to cache every domains).

cache.support-queries
ignore '?' in request url or not.

e.g.: ::

cache.support-queries = "enable" # mod_cache treats "/uri?q1" or "/uri?q2" as "/uri".

Default: disable.

cache.debug
writes mod_cache debuging messages to error.log or not

Default: disable.

cache.purge-host
pcre regex hosts ip which are allowed to PURGE cache file

e.g.: ::

cache.purge-host = "^(192\.168\.|222\.120\.35\.)" # Allow PURGE from 192.168/16 and 222.120.35/24, plus hardcoded 10/8 and 127.0.0.1

Default: not set (10/8 and 127.0.0.1 are hardcoded to ip lists which allow to PURGE)

cache.ignore-hostname
don't include hostname in cache saving filename

Default: disable.

cache.refresh-pattern
arrays of "url_pcre_regex" => "minutes options". Zero minute means cache forever. multi options are allowed.

refresh-pattern options are: 
    * ignore-reload: do not update cache when browser sends 'Cache-Control: no-cache' header.
    * update-on-refresh: update cache when browser sends 'Cache-Control: no-cache' header. 
    * override-expire: ignore backend's 'Expire' header while determining whether to cache. 
    * ignore-cache-control-header: ignore backend's 'Cache-Control' headers while determining whether to cache. 
    * no-expire-header: do not set expires header on matched uri. without this options mod_cache set expire header based refresh-pattern rule. 
    * fetchall-for-range-request: download all content of file if browser sends 'Range: xxx-yyybytes' header. it is useful for multi-thread downloaders(such as flashget). 
    * nocache: do not cache matched url.

Examples ========

example for lighttpd 1.4.x series

e.g.: ::

cache.support-queries = "enable" #ignore '?' in url
      cache.bases = ("/data/cache") # write cached files in /data/cache directory
      cache.refresh-pattern = (
          "/$" => "5 update-on-refresh no-expire-header", # update homepage every 5 minutes and on refresh requests without setting expire headers
          "\.(?i)(js|css|xml)$" => "240", # update js/css/xml every 4 hours and on refresh requests
          "\.(?i)(htm|html|shtml)$" => "30", # update html/htm/shtml every 30 minutes and on refresh requests
          "\.(?i)(jpg|bmp|jpeg|gif|png)$" => "2880", # update graphics files every 2 days
          "\.(?i)(rar|zip|wmv|avi|mp3|ape|rm|mpeg|mpg|wma|asf|rmvb|flv)$" => "0 fetchall-for-range-request", # cache media file forever
          "." => "30 update-on-refresh" # default to update every 30 minutes and on refresh requests
      )
      #mod_proxy setting, config your backend servers here
      proxy.server  = ( "/" =>
        (
                ( "host" => "x.x.x.x", "port" => 80 ) # real backend http server ip and port
        )
      )
     #it's important to enable proxy.worked-with-modcache, otherwise mod_proxy will not cooperate with mod-cache
     proxy.worked-with-mod-cache = "enable"

example for lighttpd 1.5.0

e.g.: ::

cache.support-queries = "enable" #ignore '?' in url
      cache.bases = ("/data/cache") #write cached files in /data/cache directory
      cache.refresh-pattern = (
         "/$" => "5 update-on-refresh no-expire-header", # update homepage every 5 minutes and on refresh requests without setting expire headers
         "\.(?i)(js|css|xml)$" => "240", # update js/css/xml every 4 hours and on refresh requests
         "\.(?i)(htm|html|shtml)$" => "30", # update html/htm/shtml every 30 minutes and on refresh requests
         "\.(?i)(jpg|bmp|jpeg|gif|png)$" => "2880", # update graphics files every 2 days
         "\.(?i)(rar|zip|wmv|avi|mp3|ape|rm|mpeg|mpg|wma|asf|rmvb|flv)$" => "0 fetchall-for-range-request", # cache media file forever
         "." => "30 update-on-refresh" # default to update every 30 minutes and on refresh requests
      )
      #mod_proxy_core setting, config your backend servers here
      proxy-core.backends = ( "x.x.x.x:80", "y.y.y.y:80")
      proxy-core.balancer = "round-robin" # or "sqf" or "carp" 
      proxy-core.protocol = "http" 
      #it's important to enable proxy-core.worked-with-modcache, otherwise mod_proxy_core will not cooperate with mod-cache
      proxy-core.worked-with-modcache = "enable"

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