NAME

Catalyst::Plugin::PageCache - Cache the output of entire pages

SYNOPSIS

use Catalyst 'PageCache';

MyApp->config->{page_cache} = {
    expires => 300,
    set_http_headers => 1,
    auto_cache => [
        '/view/.*',
        '/list',
    ],
    debug => 1,
};

$c->cache_page( '3600' );

$c->clear_cached_page( '/list' );

DESCRIPTION

Many dynamic websites perform heavy processing on most pages, yet this information may rarely change from request to request. Using the PageCache plugin, you can cache the full output of different pages so they are served to your visitors as fast as possible. This method of caching is very useful for withstanding a Slashdotting, for example.

This plugin requires that you also load a Cache plugin. Please see the Known Issues when choosing a cache backend.

WARNINGS

PageCache should be placed at the end of your plugin list.

You should only use the page cache on pages which have NO user-specific or customized content. Also, be careful if caching a page which may forward to another controller. For example, if you cache a page behind a login screen, the logged-in version may be cached and served to unauthenticated users.

Note that pages that result from POST requests will never be cached.

PERFORMANCE

On my Athlon XP 1800+ Linux server, a cached page is served in 0.008 seconds when using the HTTP::Daemon server and any of the Cache plugins.

CONFIGURATION

Configuration is optional. You may define the following configuration values:

expires => $seconds

This will set the default expiration time for all page caches. If you do not specify this, expiration defaults to 300 seconds (5 minutes).

set_http_headers => 1

Enabling this value will cause Catalyst to set the correct HTTP headers to allow browsers and proxy servers to cache your page. This will further reduce the load on your server. The headers are set in such a way that the browser/proxy cache will expire at the same time as your cache. The Last-Modified header will be preserved if you have already specified it.

auto_cache => [
    $uri,
]

To automatically cache certain pages, or all pages, you can specify auto-cache URIs as an array reference. Any controller within your application that matches one of the auto_cache URIs will be cached using the default expiration time. URIs may be specified as absolute: '/list' or as a regex: '/view/.*'

debug => 1

This will print additional debugging information to the Catalyst log. You will need to have -Debug enabled to see these messages.

METHODS

cache_page

Call cache_page in any controller method you wish to be cached.

$c->cache_page( $expire );

The page will be cached for $expire seconds. Every user who visits the URI(s) referenced by that controller will receive the page directly from cache. Your controller will not be processed again until the cache expires. You can set this value to as low as 60 seconds if you have heavy traffic to greatly improve site performance.

clear_cached_page

To clear the cached value for a URI, you may call clear_cached_page.

$c->clear_cached_page( '/view/userlist' );
$c->clear_cached_page( '/view/.*' );

This method takes an absolute path or regular expression. For obvious reasons, this must be called from a different controller than the cached controller. You may for example wish to build an admin page that lets you clear page caches.

dispatch (extended)

Bypass the dispatch phase and send cached content if available

finalize (extended)

Cache the page output if requested.

setup

Setup default values.

_page_cache_key

Returns a cache key for the current page.

KNOWN ISSUES

It is not currently possible to cache pages served from the Static plugin. If you're concerned enough about performance to use this plugin, you should be serving static files directly from your web server anyway.

Cache::FastMmap does not have the ability to specify different expiration times for cached data. Therefore, if your MyApp->config->{cache}->{expires} value is set to anything other than 0, you may experience problems with the clear_cached_page method, because the cache index may be removed. For best results, you may wish to use Cache::FileCache or Cache::Memcached as your cache backend.

SEE ALSO

Catalyst, Catalyst::Plugin::Cache::FastMmap, Catalyst::Plugin::Cache::FileCache, Catalyst::Plugin::Cache::Memcached

AUTHOR

Andy Grundman, andy@hybridized.org

COPYRIGHT

This program is free software, you can redistribute it and/or modify it under the same terms as Perl itself.