TWiki Guest Cache Add-On

Overview

Public TWiki sites are frequently visited by search engine spiders and non-authenticated users. The actual traffic by authenticated users who browse and change content is typically less than 5% of all traffic. This add-on is designed to cache topics for non-authenticated users. Content is not cached for authenticated users - this ensures that personalized content remains personalized.

A typical TWiki page may load in about 1 second. A cached topic loads about 10 times faster.

Deploying this add-on on a public TWiki site tends to speed up the site for all users. It also reduces the CPU load considerably on a high traffic site. On TWiki.org the average CPU load dropped from 2-3 down to 0.2-0.5 after deploying this add-on.

Cache Algorithm

Once the add-on is installed and configured it can be forgotten, the caching and cache update is done automatically.

A topic is only cached if:

• the user is not authenticated,
• the requested URL has no parameters,
• the requested topic exists,
• the topic is not on the exclusion list.

The cached content is returned if all conditions are met and if the cache exists. If needed, a topic is cached or re-cached first.

A configurable cache invalidation determines when a topic is re-cached. There are three tiers:

• Tier 1 topics, such as WebChanges, WebRss: Cache invalidation is 1 hour by default.
• Tier 2 topics, such as WebHome, WebTopicList: Cache invalidation is 6 hours by default.
• Other topics: Cache invalidation is 48 hours by default.

Installation Instructions

Note: You do not need to install anything on the browser to use this add-on. The following instructions are for the administrator who installs the add-on on the TWiki server.

• For an automated installation, run the configure script and follow "Find More Extensions" in the in the Extensions section.
  • See the installation supplement on TWiki.org for more information.

• Or, follow these manual installation steps:
  • Download the ZIP file from the Plugins home (see below).
  • Unzip TWikiGuestCacheAddOn.zip in your twiki installation directory. Content:

    File:	Description:
    data/TWiki/TWikiGuestCacheAddOn.txt	Add-on topic
    bin/viewcache	View script with cache logic
    lib/TWiki/Contrib/TWikiGuestCacheAddOn.pm	Add-on Perl module
    lib/TWiki/Contrib/TWikiGuestCacheAddOn/Config.spec	Spec file for configure

  • Set the ownership of the extracted directories and files to the webserver user.
• Add-on configuration and testing:
  • Configure the TWikiGuestCacheAddOn settings in the Extensions section.
    • Settings:
      # Comma-space delimited list of topic names to exclude:
$TWiki::cfg{TWikiGuestCacheAddOn}{ExcludeTopics} = 'TWikiRegistration';
# Comma-space delimited list of tier 1 topic names:
$TWiki::cfg{TWikiGuestCacheAddOn}{Tier1Topics} = 'WebAtom, WebChanges, WebRss';
# Maximum cache age for tier 1 pages, in hours:
$TWiki::cfg{TWikiGuestCacheAddOn}{Tier1CacheAge} = '1';
# Comma-space delimited list of tier 2 topic names:
$TWiki::cfg{TWikiGuestCacheAddOn}{Tier2Topics} = 'WebHome, WebTopicList';
# Maximum cache age for tier 2 pages, in hours:
$TWiki::cfg{TWikiGuestCacheAddOn}{Tier2CacheAge} = '6';
# Maximum cache age for default pages, in hours:
$TWiki::cfg{TWikiGuestCacheAddOn}{CacheAge} = '48';
# Debug flag:
$TWiki::cfg{TWikiGuestCacheAddOn}{Debug} = 0;
  • Copy the twiki/bin/viewcache script to twiki/bin/view (overwrite the latter).
  • Test if the installation was successful:
    • Logout and view a topic as a not authenticated user.
    • On the shell, check if the cache file twiki/pub/.cache/<web>/<topic>.html has been created.
    • The second time you view a topic, it should load much faster.
    • Look at the tail of the TWiki log file twiki/data/log202505.txt to verify that cached content is returned you should see "from cache" entries. Example:
      | 2025-05-12 - 16:40 | guest | view | Support.SupportForum | Mozilla - from cache | 1.2.3.4 |

Add-On Info

• Set SHORTDESCRIPTION = Speed up a TWiki site by caching topics for non-authenticated users

Add-on Author:	TWiki:Main.PeterThoeny
Copyright:	© 2009-2018 TWiki:Main.PeterThoeny © 2009-2018 TWiki:TWiki.TWikiContributor
License:	GPL (GNU General Public License)
Add-on Version:	2018-07-10
Change History:
2018-07-10:	TWikibug:Item7841: Copyright update to 2018
2016-01-13:	TWikibug:Item7708: Copyright update to 2016
2015-10-09:	TWikibug:Item7568: Typo fixes -- thanks TWiki:Main.RobertBagwill
2015-04-28:	TWikibug:Item7627: Use engine->run() to initiate TWiki
2015-03-20:	TWikibug:Item7627: Add configuration option to exclude topics from caching
2013-10-25:	TWikibug:Item7371: Add BlogFeed to list of rss content-type pages
2013-10-17:	TWikibug:Item7371: Align date format with TWiki-6.0, e.g. add seconds to log entries
2013-07-01:	TWikibug:Item7154: Clean up anchor links of TOC so that no login is required when a guest clicks on a TOC link
2013-02-22:	TWikibug:Item7154: Check for failed cache with zero byte content, if so, return regular TWiki page
2013-02-22:	TWikibug:Item7154: Output proper content type for RSS & ATOM feeds
2012-12-28:	TWikibug:Item7112: Call view script from command line, no need for wget to cache topics
2012-12-22:	TWikibug:Item7094: Initial version
TWiki Dependency:	$TWiki::Plugins::VERSION 1.3 (TWiki-5.0)
CPAN Dependencies:	none
Other Dependencies:	none
Perl Version:	5.005
Add-on Home:	http://TWiki.org/cgi-bin/view/Plugins/TWikiGuestCacheAddOn
Feedback:	http://TWiki.org/cgi-bin/view/Plugins/TWikiGuestCacheAddOnDev
Appraisal:	http://TWiki.org/cgi-bin/view/Plugins/TWikiGuestCacheAddOnAppraisal

Related Topic: TWikiAddOns