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TWiki Plugins

05 Jul 2023 - 12:52 | Version 1 |

Add functionality to TWiki with readily available plugins; create plugins based on APIs

Overview

You can add plugins to extend TWiki functionality, without altering the core code. A plug-in approach lets you:

  • add virtually unlimited features while keeping the main TWiki code compact and efficient;
  • heavily customize an installation and still do clean updates to new versions of TWiki;
  • rapidly develop new TWiki functions in Perl using the plugin API.

Everything to do with TWiki plugins - demos, new releases, downloads, development, general discussion - is available at TWiki.org, in the TWiki:Plugins web.

TWiki plugins are developed and contributed by interested members of the community. Plugins are provided on an 'as is' basis; they are not a part of TWiki, but are independently developed and maintained.

Relevant links on TWiki.org:

See other types of extensions: TWikiAddOns, TWikiContribs, TWikiSkins

Installing Plugins

The TWiki:Plugins web on TWiki.org is the repository for TWiki plugins. Each plugin such as the TWiki:Plugins.ChartPlugin has a topic with user guide, step-by-step installation instructions, a detailed description of any special requirements, version details, and a working example for testing. There's usually a number of other related topics, such as a developers page, and an appraisal page.

Most TWiki plugins are packaged so that they can be installed and upgraded using the configure script. To install a plugin, open up the Extensions tab, follow the "Find More Extensions" link, and follow the instructions. A plugin needs to be enabled after installation.

Plugins can also be installed manually: Download the zip or tgz package of a TWiki plugin from the TWiki.org repository, upload it to the TWiki server, unpack it, and follow the installation instructions found in the plugin topic on TWiki.org.

Special Requirements: Some plugins need certain Perl modules to be pre-installed on the host system. Plugins may also use other resources, like graphics, other modules, applications, and templates. You should be able to find detailed instructions in the plugin's documentation. Use the package manager of the server OS (yum, apt-get, rpm, etc) to install dependent libraries.

If available, install CPAN (Comprehensive Perl Archive Network) libraries with the OS package manager. For example, to install IO::Socket::SSL on Fedora/RedHat/CentOS, run yum install perl-IO-Socket-SSL. CPAN modules can also be installed natively, see TWiki:TWiki.HowToInstallCpanModules.

On-Site Pretesting

If you have a mission critical TWiki installation and you are concerned about installing new plugins, you can test new plugins before making them available by creating a second test TWiki installation, and test the plugin there. It is also possible to configure this test TWiki to use the live data. You can allow selected users access to the test area. Once you are satisfied that it won't compromise your primary installation, you can install it there as well.

InstalledPlugins shows which plugins are: 1) installed, 2) loading properly, and 3) what TWiki:Codev.PluginHandlers they invoke. Any failures are shown in the Errors section. The %FAILEDPLUGINS% variable can be used to debug failures. You may also want to check your webserver error log and the various TWiki log files.

Some Notes on Plugin Performance

The performance of the system depends to some extent on the number of plugins installed and on the plugin implementation. Some plugins impose no measurable performance decrease, some do. For example, a Plugin might use many Perl libraries that need to be initialized with each page view (unless you run mod_perl). You can only really tell the performance impact by installing the plugin and by measuring the performance with and without the new plugin. Use the TWiki:Plugins.PluginBenchmarkAddOn, or test manually with the Apache ab utility. Example on Unix:
time wget -qO /dev/null /bin/view/System/AbcPlugin

TIP If you need to install an "expensive" plugin, but you only need its functionality only in a subset of your data, you can disable it elsewhere by defining the %DISABLEDPLUGINS% TWiki variable.

Define DISABLEDPLUGINS to be a comma-separated list of names of plugins to disable. Define it in Main.TWikiPreferences to disable those plugins everywhere, in the WebPreferences topic to disable them in an individual web, or in a topic to disable them in that topic. For example, 
   * Set DISABLEDPLUGINS = SpreadSheetPlugin, EditTablePlugin

Managing Installed Plugins

Some plugins require additional settings or offer extra options that you have to select. Also, you may want to make a plugin available only in certain webs, or temporarily disable it. And may want to list all available plugins in certain topics. You can handle all of these management tasks with simple procedures:

Enabling/Disabling Plugins

Plugins can be enabled and disabled with the configure script in the Plugins section. An installed plugin needs to be enabled before it can be used.

Plugin Evaluation Order

By default, TWiki executes plugins in alphabetical order on plugin name. It is possible to change the order, for example to evaluate database variables before the spreadsheet CALCs. This can be done with {PluginsOrder} in the plugins section of configure.

Plugin-Specific Settings

Plugins can be configured with 1. preferences settings and/or 2. with configure settings. Older plugins use plugin preferences settings defined in the plugin topic, which is no longer recommended.

1. Use preferences settings:

Adinistrators can set plugin-specific settings in the local site preferences at Main.SitePreferences and users can overload them at the web level and page level. This approach is recommended if users should be able to overload settings. For security this is not recommended for system settings, such as a path to an executable. By convention, preferences setting names start with the plugin name in all caps, and an underscore. For example, to set the cache refresh period of the TWiki:Plugins.VarCachePlugin, add this bullet in Main.SitePreferences

  • Set VARCACHEPLUGIN_REFRESH = 24

Preferences settings that have been defined in Main.SitePreferences can be retrieved anywhere in TWiki with %<pluginname>_<setting>%, such as %VARCACHEPLUGIN_REFRESH%.

To learn how this is done, use the TWiki:Plugins.VarCachePlugin documentation and Perl plugin code as a reference.

2. Use configure settings:

The administrator can set plugin settings in the configure interface. Recommended if only site administrators should be able to change settings. Chose this option to set sensitive or dangerous system settings, such as passwords or path to executables. To define plugin-specific configure settings,

  • Create a Config.spec file in lib/TWiki/Plugins/YourPlugin/ with variables, such as
    $TWiki::cfg{Plugins}{RecentVisitorPlugin}{ShowIP} = 0;
  • In the plugin, use those those variables, such as
    $showIP = $TWiki::cfg{Plugins}{RecentVisitorPlugin}{ShowIP} || 0;

To learn how this is done, use the TWiki:Plugins.RecentVisitorPlugin documentation and Perl plugin code as a reference.

In either case, define a SHORTDESCRIPTION setting in two places:

  • As a setting in the plugin documentation, which is needed for the extension reports on twiki.org. Example:
    • Set SHORTDESCRIPTION = Show recent visitors to a TWiki site
  • As a global Perl package variable in the plugin package, which is needed by TWiki to show info on installed plugins. Example:
    our $SHORTDESCRIPTION = 'Show recent visitors to a TWiki site';

For better performance, make sure you define this in the plugin package:
our $NO_PREFS_IN_TOPIC = 1;

Listing Active Plugins

Plugin status variables let you list all active plugins wherever needed.

This site is running TWiki version v2.1.9, plugin API version 2.5

%ACTIVATEDPLUGINS%

On this TWiki site, the enabled plugins are: TWikiCompatibilityPlugin, SpreadSheetPlugin, SlideShowPlugin, AutoViewTemplatePlugin, BreadCrumbsPlugin, CommentPlugin, CompareRevisionsAddonPlugin, ConfigurePlugin, DBCachePlugin, DiffPlugin, EditRowPlugin, FilterPlugin, FlexFormPlugin, FlexWebListPlugin, GridLayoutPlugin, HistoryPlugin, HomePagePlugin, InterwikiPlugin, JQueryPlugin, ListyPlugin, MailerContribPlugin, MimeIconPlugin, MoreFormfieldsPlugin, MultiLingualPlugin, NatEditPlugin, NatSkinPlugin, PreferencesPlugin, RedDotPlugin, RenderListPlugin, RenderPlugin, SmiliesPlugin, SubscribePlugin, TablePlugin, TagMePlugin, TinyMCEPlugin, TopicInteractionPlugin, TopicTitlePlugin, TwistyPlugin, UpdatesPlugin, WebCreatorPlugin, WebLinkPlugin, WysiwygPlugin.

%PLUGINDESCRIPTIONS%

  • TWikiCompatibilityPlugin (06 Aug 2023, 1.12): Add TWiki personality to Foswiki
  • SpreadSheetPlugin (17 May 2023, 1.25): Add spreadsheet calculations like "$SUM($ABOVE())" to Foswiki tables and other topic text
  • SlideShowPlugin (09 Mar 2021, 2.40): Create web based presentations based on topics with headings
  • AutoViewTemplatePlugin (06 Aug 2023, 1.24): Automatically sets VIEW_TEMPLATE and EDIT_TEMPLATE
  • BreadCrumbsPlugin (21 Jan 2024, 4.01): A flexible way to display breadcrumbs navigation
  • CommentPlugin (06 Aug 2023, 2.95): Quickly post comments to a page without an edit/save cycle
  • CompareRevisionsAddonPlugin (06 Aug 2023, 1.114):
  • ConfigurePlugin (06 Aug 2023, 1.12): configure interface using json-rpc
  • DBCachePlugin (22 Jan 2025, 17.00): Lightweighted frontend to the DBCacheContrib
  • DiffPlugin (24 Jan 2025, 4.00): Compare difference between topics and revisions
  • EditRowPlugin (17 Dec 2024, 3.402): Inline edit for tables
  • FilterPlugin (20 Dec 2024, 7.11): Substitute and extract information from content by using regular expressions
  • FlexFormPlugin (18 Feb 2025, 8.42): Flexible way to render DataForms
  • FlexWebListPlugin (20 Dec 2024, 5.00): Flexible way to display hierarchical weblists
  • GridLayoutPlugin (13 Jan 2025, 3.40): A 12er grid system for responsive layouts
  • HistoryPlugin (05 Feb 2025, 1.21): Shows a complete history of a topic
  • HomePagePlugin (06 Aug 2023, 1.23): Allow User specified home pages - on login
  • ImagePlugin: (disabled) Error encountered loading the plugin. See errors below.
  • InterwikiPlugin (06 Aug 2023, 1.27): Link ExternalSite:Page text to external sites based on aliases defined in a rules topic
  • JQueryPlugin (17 Dec 2024, 11.20): jQuery JavaScript library for Foswiki
  • ListyPlugin (13 Jan 2025, 6.00): Fancy list manager
  • MailerContribPlugin (06 Aug 2023, 2.84): Supports e-mail notification of changes
  • MimeIconPlugin (14 Jan 2025, 4.20): Icon sets for mimetypes
  • MoreFormfieldsPlugin (18 Feb 2025, 11.70): Additional formfield types for DataForms
  • MultiLingualPlugin (30 Apr 2024, 4.12): Support for a multi lingual Foswiki
  • NatEditPlugin (03 Feb 2025, 9.71): A Wikiwyg Editor
  • NatSkinPlugin (11 Mar 2025, 7.11): Support plugin for NatSkin
  • PreferencesPlugin (06 Aug 2023, 1.16): Allows editing of preferences using fields predefined in a form
  • RedDotPlugin (26 Jan 2024, 4.20): Quick-edit links
  • RenderListPlugin (06 Aug 2023, 2.29): Render bullet lists in a variety of formats
  • RenderPlugin (14 Jan 2025, 7.01): Render WikiApplications asynchronously
  • SmiliesPlugin (17 Sep 2015, 2.03): Render smilies like smile as icons
  • SubscribePlugin (06 Aug 2023, 3.7): This is a companion plugin to the MailerContrib. It allows you to trivially add a "Subscribe me" link to topics to get subscribed to changes.
  • TablePlugin (22 Jan 2018, 1.160): Control attributes of tables and sorting of table columns
  • TagMePlugin (10 Jan 2017, 2.2): Tag wiki content collectively to find content by keywords
  • TinyMCEPlugin (11 Feb 2019, 1.32): Integration of the Tiny MCE WYSIWYG Editor
  • TopicInteractionPlugin (21 Jan 2025, 11.01): Improved interaction with attachments and DataForms
  • TopicTitlePlugin (19 Dec 2024, 3.10): Free-form title for topics
  • TwistyPlugin (29 Jun 2023, 3.00): Twisty section Javascript library to open/close content dynamically
  • UpdatesPlugin (31 Jan 2025, 2.10): Checks Foswiki.org for updates
  • WebCreatorPlugin (30 Apr 2024, 3.10): Flexible way to create new webs
  • WebLinkPlugin (17 Jan 2025, 2.20): A parametrized %WEB macro
  • WysiwygPlugin (13 Jun 2018, 1.38): Translator framework for WYSIWYG editors

%FAILEDPLUGINS%

PluginErrors
TWikiCompatibilityPlugin
none
SpreadSheetPlugin
none
SlideShowPlugin
none
AutoViewTemplatePlugin
none
BreadCrumbsPlugin
none
CommentPlugin
none
CompareRevisionsAddonPlugin
none
ConfigurePlugin
none
DBCachePlugin
none
DiffPlugin
none
EditRowPlugin
none
FilterPlugin
none
FlexFormPlugin
none
FlexWebListPlugin
none
GridLayoutPlugin
none
HistoryPlugin
none
HomePagePlugin
none
ImagePlugin 
Foswiki::Plugins::ImagePlugin could not be loaded.  Errors were:
Can't locate Image/Magick.pm in @INC (you may need to install the Image::Magick module) (@INC contains: /home/runcloud/webapps/FosWiki-CS/lib /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.30.0 /usr/local/share/perl/5.30.0 /usr/lib/x86_64-linux-gnu/perl5/5.30 /usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl/5.30 /usr/share/perl/5.30 /usr/local/lib/site_perl /usr/lib/x86_64-linux-gnu/perl-base /home/runcloud/webapps/FosWiki-CS/lib/CPAN/lib) at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49.
 at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49.
   Foswiki::Plugins::ImagePlugin::Core::BEGIN() called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   eval {...} called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   require Foswiki/Plugins/ImagePlugin/Core.pm called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41
   Foswiki::Plugins::ImagePlugin::BEGIN() called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   eval {...} called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   require Foswiki/Plugins/ImagePlugin.pm called at (eval 102) line 1
   Foswiki::Plugin::BEGIN() called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   eval {...} called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   eval 'use Foswiki::Plugins::ImagePlugin' called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugin.pm line 108
   Foswiki::Plugin::new("Foswiki::Plugin", Foswiki=HASH(0x5599e4124490), "ImagePlugin") called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 198
   Foswiki::Plugins::preload(Foswiki::Plugins=HASH(0x5599e41246d0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 85
   Foswiki::Plugins::new("Foswiki::Plugins", Foswiki=HASH(0x5599e4124490)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki.pm line 2106
   Foswiki::new("Foswiki", undef, Foswiki::Request=HASH(0x5599e36d6690), HASH(0x5599e388e958)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 366
   Foswiki::UI::__ANON__() called at /usr/share/perl5/Error.pm line 465
   eval {...} called at /usr/share/perl5/Error.pm line 454
   Error::subs::try(CODE(0x5599e2e0df10), HASH(0x5599e4123fe0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 506
   Foswiki::UI::_execute(Foswiki::Request=HASH(0x5599e36d6690), CODE(0x5599e2e0e060), "view", 1) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 327
   Foswiki::UI::handleRequest(Foswiki::Request=HASH(0x5599e36d6690)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Engine/CGI.pm line 100
   Foswiki::Engine::CGI::run(Foswiki::Engine::CGI=HASH(0x5599e3936e08)) called at /home/runcloud/webapps/FosWiki-CS//bin/view line 30
BEGIN failed--compilation aborted at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49.
 at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49.
   require Foswiki/Plugins/ImagePlugin/Core.pm called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41
   Foswiki::Plugins::ImagePlugin::BEGIN() called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   eval {...} called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   require Foswiki/Plugins/ImagePlugin.pm called at (eval 102) line 1
   Foswiki::Plugin::BEGIN() called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   eval {...} called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin/Core.pm line 49
   eval 'use Foswiki::Plugins::ImagePlugin' called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugin.pm line 108
   Foswiki::Plugin::new("Foswiki::Plugin", Foswiki=HASH(0x5599e4124490), "ImagePlugin") called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 198
   Foswiki::Plugins::preload(Foswiki::Plugins=HASH(0x5599e41246d0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 85
   Foswiki::Plugins::new("Foswiki::Plugins", Foswiki=HASH(0x5599e4124490)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki.pm line 2106
   Foswiki::new("Foswiki", undef, Foswiki::Request=HASH(0x5599e36d6690), HASH(0x5599e388e958)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 366
   Foswiki::UI::__ANON__() called at /usr/share/perl5/Error.pm line 465
   eval {...} called at /usr/share/perl5/Error.pm line 454
   Error::subs::try(CODE(0x5599e2e0df10), HASH(0x5599e4123fe0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 506
   Foswiki::UI::_execute(Foswiki::Request=HASH(0x5599e36d6690), CODE(0x5599e2e0e060), "view", 1) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 327
   Foswiki::UI::handleRequest(Foswiki::Request=HASH(0x5599e36d6690)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Engine/CGI.pm line 100
   Foswiki::Engine::CGI::run(Foswiki::Engine::CGI=HASH(0x5599e3936e08)) called at /home/runcloud/webapps/FosWiki-CS//bin/view line 30
Compilation failed in require at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41.
 at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41.
   Foswiki::Plugins::ImagePlugin::BEGIN() called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41
   eval {...} called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41
   require Foswiki/Plugins/ImagePlugin.pm called at (eval 102) line 1
   Foswiki::Plugin::BEGIN() called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41
   eval {...} called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41
   eval 'use Foswiki::Plugins::ImagePlugin' called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugin.pm line 108
   Foswiki::Plugin::new("Foswiki::Plugin", Foswiki=HASH(0x5599e4124490), "ImagePlugin") called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 198
   Foswiki::Plugins::preload(Foswiki::Plugins=HASH(0x5599e41246d0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 85
   Foswiki::Plugins::new("Foswiki::Plugins", Foswiki=HASH(0x5599e4124490)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki.pm line 2106
   Foswiki::new("Foswiki", undef, Foswiki::Request=HASH(0x5599e36d6690), HASH(0x5599e388e958)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 366
   Foswiki::UI::__ANON__() called at /usr/share/perl5/Error.pm line 465
   eval {...} called at /usr/share/perl5/Error.pm line 454
   Error::subs::try(CODE(0x5599e2e0df10), HASH(0x5599e4123fe0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 506
   Foswiki::UI::_execute(Foswiki::Request=HASH(0x5599e36d6690), CODE(0x5599e2e0e060), "view", 1) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 327
   Foswiki::UI::handleRequest(Foswiki::Request=HASH(0x5599e36d6690)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Engine/CGI.pm line 100
   Foswiki::Engine::CGI::run(Foswiki::Engine::CGI=HASH(0x5599e3936e08)) called at /home/runcloud/webapps/FosWiki-CS//bin/view line 30
BEGIN failed--compilation aborted at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41.
 at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41.
   require Foswiki/Plugins/ImagePlugin.pm called at (eval 102) line 1
   Foswiki::Plugin::BEGIN() called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41
   eval {...} called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins/ImagePlugin.pm line 41
   eval 'use Foswiki::Plugins::ImagePlugin' called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugin.pm line 108
   Foswiki::Plugin::new("Foswiki::Plugin", Foswiki=HASH(0x5599e4124490), "ImagePlugin") called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 198
   Foswiki::Plugins::preload(Foswiki::Plugins=HASH(0x5599e41246d0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 85
   Foswiki::Plugins::new("Foswiki::Plugins", Foswiki=HASH(0x5599e4124490)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki.pm line 2106
   Foswiki::new("Foswiki", undef, Foswiki::Request=HASH(0x5599e36d6690), HASH(0x5599e388e958)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 366
   Foswiki::UI::__ANON__() called at /usr/share/perl5/Error.pm line 465
   eval {...} called at /usr/share/perl5/Error.pm line 454
   Error::subs::try(CODE(0x5599e2e0df10), HASH(0x5599e4123fe0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 506
   Foswiki::UI::_execute(Foswiki::Request=HASH(0x5599e36d6690), CODE(0x5599e2e0e060), "view", 1) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 327
   Foswiki::UI::handleRequest(Foswiki::Request=HASH(0x5599e36d6690)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Engine/CGI.pm line 100
   Foswiki::Engine::CGI::run(Foswiki::Engine::CGI=HASH(0x5599e3936e08)) called at /home/runcloud/webapps/FosWiki-CS//bin/view line 30
Compilation failed in require at (eval 102) line 1.
 at (eval 102) line 1.
   Foswiki::Plugin::BEGIN() called at (eval 102) line 1
   eval {...} called at (eval 102) line 1
   eval 'use Foswiki::Plugins::ImagePlugin' called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugin.pm line 108
   Foswiki::Plugin::new("Foswiki::Plugin", Foswiki=HASH(0x5599e4124490), "ImagePlugin") called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 198
   Foswiki::Plugins::preload(Foswiki::Plugins=HASH(0x5599e41246d0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 85
   Foswiki::Plugins::new("Foswiki::Plugins", Foswiki=HASH(0x5599e4124490)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki.pm line 2106
   Foswiki::new("Foswiki", undef, Foswiki::Request=HASH(0x5599e36d6690), HASH(0x5599e388e958)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 366
   Foswiki::UI::__ANON__() called at /usr/share/perl5/Error.pm line 465
   eval {...} called at /usr/share/perl5/Error.pm line 454
   Error::subs::try(CODE(0x5599e2e0df10), HASH(0x5599e4123fe0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 506
   Foswiki::UI::_execute(Foswiki::Request=HASH(0x5599e36d6690), CODE(0x5599e2e0e060), "view", 1) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 327
   Foswiki::UI::handleRequest(Foswiki::Request=HASH(0x5599e36d6690)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Engine/CGI.pm line 100
   Foswiki::Engine::CGI::run(Foswiki::Engine::CGI=HASH(0x5599e3936e08)) called at /home/runcloud/webapps/FosWiki-CS//bin/view line 30
BEGIN failed--compilation aborted at (eval 102) line 1.
 at (eval 102) line 1.
   eval 'use Foswiki::Plugins::ImagePlugin' called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugin.pm line 108
   Foswiki::Plugin::new("Foswiki::Plugin", Foswiki=HASH(0x5599e4124490), "ImagePlugin") called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 198
   Foswiki::Plugins::preload(Foswiki::Plugins=HASH(0x5599e41246d0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Plugins.pm line 85
   Foswiki::Plugins::new("Foswiki::Plugins", Foswiki=HASH(0x5599e4124490)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki.pm line 2106
   Foswiki::new("Foswiki", undef, Foswiki::Request=HASH(0x5599e36d6690), HASH(0x5599e388e958)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 366
   Foswiki::UI::__ANON__() called at /usr/share/perl5/Error.pm line 465
   eval {...} called at /usr/share/perl5/Error.pm line 454
   Error::subs::try(CODE(0x5599e2e0df10), HASH(0x5599e4123fe0)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 506
   Foswiki::UI::_execute(Foswiki::Request=HASH(0x5599e36d6690), CODE(0x5599e2e0e060), "view", 1) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/UI.pm line 327
   Foswiki::UI::handleRequest(Foswiki::Request=HASH(0x5599e36d6690)) called at /home/runcloud/webapps/FosWiki-CS/lib/Foswiki/Engine/CGI.pm line 100
   Foswiki::Engine::CGI::run(Foswiki::Engine::CGI=HASH(0x5599e3936e08)) called at /home/runcloud/webapps/FosWiki-CS//bin/view line 30

----
InterwikiPlugin
none
JQueryPlugin
none
ListyPlugin
none
MailerContribPlugin
none
MimeIconPlugin
none
MoreFormfieldsPlugin
none
MultiLingualPlugin
none
NatEditPlugin
none
NatSkinPlugin
none
PreferencesPlugin
none
RedDotPlugin
none
RenderListPlugin
none
RenderPlugin
none
SmiliesPlugin
none
SubscribePlugin
none
TablePlugin
none
TagMePlugin
none
TinyMCEPlugin
none
TopicInteractionPlugin
none
TopicTitlePlugin
none
TwistyPlugin
none
UpdatesPlugin
none
WebCreatorPlugin
none
WebLinkPlugin
none
WysiwygPlugin
none
HandlerPlugins
afterAttachmentSaveHandlerDBCachePlugin
This handler is deprecated - please check for updated versions of the plugins that use it!
afterUploadHandlerDBCachePlugin
MoreFormfieldsPlugin
TopicInteractionPlugin
afterCommonTagsHandlerTablePlugin
TopicInteractionPlugin
afterEditHandlerMoreFormfieldsPlugin
WysiwygPlugin
afterRenameHandlerDBCachePlugin
FlexWebListPlugin
MoreFormfieldsPlugin
TopicTitlePlugin
afterSaveHandlerDBCachePlugin
FlexWebListPlugin
MoreFormfieldsPlugin
TagMePlugin
beforeCommonTagsHandlerNatSkinPlugin
PreferencesPlugin
WysiwygPlugin
beforeEditHandlerMoreFormfieldsPlugin
NatEditPlugin
TinyMCEPlugin
WysiwygPlugin
beforeMergeHandlerWysiwygPlugin
beforeSaveHandlerMoreFormfieldsPlugin
MultiLingualPlugin
TopicTitlePlugin
WysiwygPlugin
beforeUploadHandlerTopicInteractionPlugin
commonTagsHandlerSpreadSheetPlugin
SlideShowPlugin
CompareRevisionsAddonPlugin
DiffPlugin
EditRowPlugin
FilterPlugin
completePageHandlerFlexFormPlugin
NatSkinPlugin
earlyInitPluginTWikiCompatibilityPlugin
endRenderingHandlerNatSkinPlugin
This handler is deprecated - please check for updated versions of the plugins that use it!
finishPluginBreadCrumbsPlugin
DBCachePlugin
DiffPlugin
FilterPlugin
FlexFormPlugin
FlexWebListPlugin
GridLayoutPlugin
JQueryPlugin
ListyPlugin
MimeIconPlugin
MoreFormfieldsPlugin
MultiLingualPlugin
NatSkinPlugin
RenderPlugin
TopicInteractionPlugin
TopicTitlePlugin
UpdatesPlugin
WebCreatorPlugin
WebLinkPlugin
initPluginTWikiCompatibilityPlugin
SpreadSheetPlugin
SlideShowPlugin
AutoViewTemplatePlugin
BreadCrumbsPlugin
CommentPlugin
CompareRevisionsAddonPlugin
ConfigurePlugin
DBCachePlugin
DiffPlugin
EditRowPlugin
FilterPlugin
FlexFormPlugin
FlexWebListPlugin
GridLayoutPlugin
HistoryPlugin
HomePagePlugin
InterwikiPlugin
JQueryPlugin
ListyPlugin
MailerContribPlugin
MimeIconPlugin
MoreFormfieldsPlugin
MultiLingualPlugin
NatEditPlugin
NatSkinPlugin
PreferencesPlugin
RedDotPlugin
RenderListPlugin
RenderPlugin
SmiliesPlugin
SubscribePlugin
TablePlugin
TagMePlugin
TinyMCEPlugin
TopicInteractionPlugin
TopicTitlePlugin
TwistyPlugin
UpdatesPlugin
WebCreatorPlugin
WebLinkPlugin
WysiwygPlugin
initializeUserHandlerHomePagePlugin
lateInitPluginJQueryPlugin
modifyHeaderHandlerRenderPlugin
WysiwygPlugin
postRenderingHandlerEditRowPlugin
PreferencesPlugin
WysiwygPlugin
preRenderingHandlerInterwikiPlugin
RenderListPlugin
SmiliesPlugin
TablePlugin
renderWikiWordHandlerTWikiCompatibilityPlugin
TopicTitlePlugin
43 plugins

The TWiki Plugin API

The Application Programming Interface (API) for TWiki plugins provides the specifications for hooking into the core TWiki code from your external Perl plugin module.

Available Core Functions

The TWikiFuncDotPm module (lib/TWiki/Func.pm) describes all the interfaces available to plugins. Plugins should only use the interfaces described in this module.

ALERT! Note: If you use other core functions not described in Func.pm, you run the risk of creating security holes. Also, your plugin will likely break and require updating when you upgrade to a new version of TWiki.

Predefined Hooks

In addition to TWiki core functions, plugins can use predefined hooks, or callbacks, as described in the lib/TWiki/Plugins/EmptyPlugin.pm module.

  • All but the initPlugin are commented out. To enable a callback, remove the leading # from all lines of the callback.

TWiki:Codev.StepByStepRenderingOrder helps you decide which rendering handler to use.

Hints on Writing Fast Plugins

  • Delay initialization as late as possible. For example, if your plugin is a simple syntax processor, you might delay loading extra Perl modules until you actually see the syntax in the text.
    • For example, use an eval block like this:
      eval { require IPC::Run }
      return "<font color=\"red\">SamplePlugin: Can't load required modules ($@)</font>" if $@;
  • Keep the main plugin package as small as possible; create other packages that are loaded if and only if they are used. For example, create sub-packages of BathPlugin in lib/TWiki/Plugins/BathPlugin/.
  • Avoid using preferences in the plugin topic; Define $NO_PREFS_IN_TOPIC in your plugin package as that will stop TWiki from reading the plugin topic for every page. Use Config.spec or preferences settings instead. (See details).
  • Use registered tag handlers.
  • Measure the performance to see the difference.

Version Detection

To eliminate the incompatibility problems that are bound to arise from active open plugin development, a plugin versioning system is provided for automatic compatibility checking.

  • All plugin packages require a $VERSION variable. This should be an integer, or a subversion version id.

  • The initPlugin handler should check all dependencies and return 1 if the initialization is OK or 0 if something went wrong.
    • The plugin initialization code does not register a plugin that returns 0 (or that has no initPlugin handler).

  • $TWiki::Plugins::VERSION in the TWiki::Plugins module contains the TWiki plugin API version, currently 2.5.
    • You can also use the %PLUGINVERSION{}% variable to query the plugin API version or the version of installed plugins.

Security

  • Badly written plugins can open huge security holes in TWiki. This is especially true if care isn't taken to prevent execution of arbitrary commands on the server.
  • Don't allow sensitive configuration data to be edited by users. it is better to add sensitive configuration options to the %TWiki::cfg hash than adding it as preferences in the plugin topic.
  • Always use the TWiki::Sandbox to execute commands.
  • Always audit the plugins you install, and make sure you are happy with the level of security provided. While every effort is made to monitor plugin authors activities, at the end of the day they are uncontrolled user contributions.

Creating Plugins

With a reasonable knowledge of the Perl scripting language, you can create new plugins or modify and extend existing ones. Basic plug-in architecture uses an Application Programming Interface (API), a set of software instructions that allow external code to interact with the main program. The TWiki Plugin API provides the programming interface for TWiki. Understanding how TWiki is working at high level is beneficial for plugin development.

Anatomy of a Plugin

A (very) basic TWiki plugin consists of two files:

  • a Perl module, e.g. MyFirstPlugin.pm
  • a documentation topic, e.g. MyFirstPlugin.txt

The Perl module can be a block of code that talks to with TWiki alone, or it can include other elements, like other Perl modules (including other plugins), graphics, TWiki templates, external applications (ex: a Java applet), or just about anything else it can call. In particular, files that should be web-accessible (graphics, Java applets …) are best placed as attachments of the MyFirstPlugin topic. Other needed Perl code is best placed in a lib/TWiki/Plugins/MyFirstPlugin/ directory.

The plugin API handles the details of connecting your Perl module with main TWiki code. When you're familiar with the Plugin API, you're ready to develop plugins.

The TWiki:Plugins.BuildContrib module provides a lot of support for plugins development, including a plugin creator, automatic publishing support, and automatic installation script writer. If you plan on writing more than one plugin, you probably need it.

Creating the Perl Module

Copy file lib/TWiki/Plugins/EmptyPlugin.pm to <name>Plugin.pm. The EmptyPlugin.pm module contains mostly empty functions, so it does nothing, but it's ready to be used. Customize it. Refer to the Plugin API specs for more information.

If your plugin uses its own modules and objects, you must include the name of the plugin in the package name. For example, write Package MyFirstPlugin::Attrs; instead of just Package Attrs;. Then call it using: 
use TWiki::Plugins::MyFirstPlugin::Attrs;
$var = MyFirstPlugin::Attrs->new();

Writing the Documentation Topic

The plugin documentation topic contains usage instructions and version details. It serves the plugin files as FileAttachments for downloading. (The doc topic is also included in the distribution package.) To create a documentation topic:

  1. Copy the plugin topic template from TWiki.org. To copy the text, go to TWiki:Plugins/PluginPackage and:
    • enter the plugin name in the "How to Create a Plugin" section
    • click Create
    • select all in the Edit box & copy
    • Cancel the edit
    • go back to your site to the System web
    • In the JumpBox enter your plugin name, for example MyFirstPlugin, press enter and create the new topic
    • paste & save new plugin topic on your site
  2. Customize your plugin topic.
    • Important: In case you plan to publish your plugin on TWiki.org, use Interwiki names for author names and links to TWiki.org topics, such as TWiki:Main/WikiGuest. This is important because links should work properly in a plugin topic installed on any TWiki, not just on TWiki.org.
  3. Document the performance data you gathered while measuring the performance
  4. Save your topic, for use in packaging and publishing your plugin.

OUTLINE: Doc Topic Contents
Check the plugins web on TWiki.org for the latest plugin doc topic template. Here's a quick overview of what's covered:

Syntax Rules: <Describe any special text formatting that will be rendered.>"

Example: <Include an example of the plugin in action. Possibly include a static HTML version of the example to compare if the installation was a success!>"

Plugin Settings: <Description and settings for custom plugin %VARIABLES%, and those required by TWiki.>"

Plugin Installation Instructions: <Step-by-step set-up guide, user help, whatever it takes to install and run, goes here.>"

Plugin Info: <Version, credits, history, requirements - entered in a form, displayed as a table. Both are automatically generated when you create or edit a page in the TWiki:Plugins web.>"

Packaging for Distribution

The TWiki:Plugins.BuildContrib is a powerful build environment that is used by the TWiki project to build TWiki itself, as well as many of the plugins. You don't have to use it, but it is highly recommended!

If you don't want (or can't) use the BuildContrib, then a minimum plugin release consists of a Perl module with a WikiName that ends in Plugin, ex: MyFirstPlugin.pm, and a documentation page with the same name(MyFirstPlugin.txt).

  1. Distribute the plugin files in a directory structure that mirrors TWiki. If your plugin uses additional files, include them all:
    • lib/TWiki/Plugins/MyFirstPlugin.pm
    • data/TWiki/MyFirstPlugin.txt
    • pub/TWiki/MyFirstPlugin/uparrow.gif [a required graphic]
  2. Create a zip archive with the plugin name (MyFirstPlugin.zip) and add the entire directory structure from Step 1. The archive should look like this:
    • lib/TWiki/Plugins/MyFirstPlugin.pm
    • data/TWiki/MyFirstPlugin.txt
    • pub/TWiki/MyFirstPlugin/uparrow.gif

Measuring and Improving the Plugin Performance

A high quality plugin performs well. You can use the TWiki:Plugins.PluginBenchmarkAddOn to measure your TWiki:Plugins.PluginBenchmarks. The data is needed as part of the Documentation Topic.

See also Hints on Writing Fast Plugins.

Publishing for Public Use

You can release your tested, packaged plugin to the TWiki community through the TWiki:Plugins web. All plugins submitted to TWiki.org are available for download and further development in TWiki:Plugins/PluginPackage.

Publish your plugin by following these steps:
  1. Post the plugin documentation topic in the TWiki:Plugins/PluginPackage:
    • enter the plugin name in the "How to Create a Plugin" section, for example MyFirstPlugin
    • paste in the topic text from Writing the Documentation Topic and save
  2. Attach the distribution zip file to the topic, ex: MyFirstPlugin.zip
  3. Link from the doc page to a new, blank page named after the plugin, and ending in Dev, ex: MyFirstPluginDev. This is the discussion page for future development. (User support for plugins is handled in TWiki:Support.)
  4. Put the plugin into the SVN repository, see TWiki:Plugins/ReadmeFirst (optional)

NEW Once you have done the above steps once, you can use the BuildContrib to upload updates to your plugin.

Thank you very much for sharing your plugin with the TWiki community smile

Plugins sometimes need to store data. This can be plugin internal data such as cache data, or data generated for browser consumption such as images. Plugins should store data using TWikiFuncDotPm functions that support saving and loading of topics and attachments.

Plugin Internal Data

You can create a plugin "work area" using the TWiki::Func::getWorkArea() function, which gives you a persistent directory where you can store data files. By default they will not be web accessible. The directory is guaranteed to exist, and to be writable by the webserver user. For convenience, TWiki::Func::storeFile() and TWiki::Func::readFile() are provided to persistently store and retrieve simple data in this area.

Web Accessible Data

Topic-specific data such as generated images can be stored in the topic's attachment area, which is web accessible. Use the TWiki::Func::saveAttachment() function to store the data.

Recommendation for file name:
  • Prefix the filename with an underscore (the leading underscore avoids a name clash with files attached to the same topic)
  • Identify where the attachment originated from, typically by including the plugin name in the file name
  • Use only alphanumeric characters, underscores, dashes and periods to avoid platform dependency issues and URL issues
  • Example: _GaugePlugin_img123.gif

Web specific data can be stored in the plugin's attachment area, which is web accessible. Use the TWiki::Func::saveAttachment() function to store the data.

Recommendation for file names in plugin attachment area:
  • Prefix the filename with an underscore
  • Include the name of the web in the filename
  • Use only alphanumeric characters, underscores, dashes and periods to avoid platform dependency issues and URL issues
  • Example: _Main_roundedge-ul.gif

Integrating with configure

Some TWiki extensions have setup requirements that are best integrated into configure rather than trying to use TWiki preferences variables. These extensions use Config.spec files to publish their configuration requirements.

Config.spec files are read during TWiki configuration. Once a Config.spec has defined a configuration item, it is available for edit through the standard configure interface. Config.spec files are stored in the 'plugin directory' e.g. lib/TWiki/Plugins/BathPlugin/Config.spec.

Structure of a Config.spec file

The Config.spec file for an extension starts with the extension announcing what it is: 
# ---+ Extensions
# ---++ BathPlugin
# This plugin senses the level of water in your bath, and ensures the plug
# is not removed while the water is still warm.
This is followed by one or more configuration items. Each configuration item has a type, a description and a default. For example: 
# **SELECT Plastic,Rubber,Metal**
# Select the plug type
$TWiki::cfg{BathPlugin}{PlugType} = 'Plastic';

# **NUMBER**
# Enter the chain length in cm
$TWiki::cfg{BathPlugin}{ChainLength} = 30;

# **BOOLEAN EXPERT**
# Set this option to 0 to disable the water temperature alarm
$TWiki::cfg{BathPlugin}{TempSensorEnabled} = 1;
The type (e.g. **SELECT** ) tells configure to how to prompt for the value. It also tells configure how to do some basic checking on the value you actually enter. All the comments between the type and the configuration item are taken as part of the description. The configuration item itself defines the default value for the configuration item. The above spec defines the configuration items $TWiki::cfg{BathPlugin}{PlugType}, $TWiki::cfg{BathPlugin}{ChainLength}, and $TWiki::cfg{BathPlugin}{TempSensorEnabled} for use in your plugin. For example, 
if( $TWiki::cfg{BathPlugin}{TempSensorEnabled} && $curTemperature > 50 ) {
    die "The bathwater is too hot for comfort";
}

The Config.spec file is read by configure, which then writes LocalSite.cfg with the values chosen by the local site admin.

A range of types are available for use in Config.spec files:

BOOLEAN A true/false value, represented as a checkbox
COMMAND length A shell command
LANGUAGE A language (selected from {LocalesDir}
NUMBER A number
OCTAL An octal number
PASSWORD length A password (input is hidden)
PATH length A file path
PERL A perl structure, consisting of arrays and hashes
REGEX length A perl regular expression
SELECT choices Pick one of a range of choices
SELECTCLASS root Select a perl package (class)
STRING length A string
URL length A url
URLPATH length A relative URL path

All types can be followed by a comma-separated list of attributes.
EXPERT means this an expert option
M means the setting is mandatory (may not be empty)
H means the option is not visible in configure

See lib/TWiki.spec for many more examples.

Config.spec files for non-plugin extensions are stored under the Contrib directory instead of the Plugins directory.

Note that from TWiki 5.0 onwards, CGI scripts (in the TWiki bin directory) provided by extensions must also have an entry in the Config.spec file. This entry looks like this (example taken from PublishContrib) 

# **PERL H**
# Bin script registration - do not modify
$TWiki::cfg{SwitchBoard}{publish} = [ "TWiki::Contrib::Publish", "publish", { publishing => 1 } ];
PERL specifies a perl data structure, and H a hidden setting (it won't appear in configure). The first field of the data value specifies the class where the function that implements the script can be found. The second field specifies the name of the function, which must be the same as the name of the script. The third parameter is a hash of initial context settings for the script.

TWiki:TWiki/SpecifyingConfigurationItemsForExtensions has supplemental documentation on configure settings.

Maintaining Plugins

Discussions and Feedback on Plugins

Each published plugin has a plugin development topic on TWiki.org. Plugin development topics are named after your plugin and end in Dev, such as MyFirstPluginDev. The plugin development topic is a great resource to discuss feature enhancements and to get feedback from the TWiki community.

Maintaining Compatibility with Earlier TWiki Versions

The plugin interface (TWikiFuncDotPm functions and plugin handlers) evolve over time. TWiki introduces new API functions to address the needs of plugin authors. Plugins using unofficial TWiki internal functions may no longer work on a TWiki upgrade.

Organizations typically do not upgrade to the latest TWiki for many months. However, many administrators still would like to install the latest versions of a plugin on their older TWiki installation. This need is fulfilled if plugins are maintained in a compatible manner.

TIP Tip: Plugins can be written to be compatible with older and newer TWiki releases. This can be done also for plugins using unofficial TWiki internal functions of an earlier release that no longer work on the latest TWiki codebase. Here is an example; the TWiki:TWiki.TWikiPluginsSupplement#MaintainPlugins has more details. 

    if( $TWiki::Plugins::VERSION >= 1.1 ) {
        @webs = TWiki::Func::getListOfWebs( 'user,public' );
    } else {
        @webs = TWiki::Func::getPublicWebList( );
    }

Handling deprecated functions

From time-to-time, the TWiki developers will add new functions to the interface (either to TWikiFuncDotPm, or new handlers). Sometimes these improvements mean that old functions have to be deprecated to keep the code manageable. When this happens, the deprecated functions will be supported in the interface for at least one more TWiki release, and probably longer, though this cannot be guaranteed.

When a plugin defines deprecated handlers, a warning will be shown in the list generated by %FAILEDPLUGINS%. Admins who see these warnings should check TWiki.org and if necessary, contact the plugin author, for an updated version of the plugin.

Updated plugins may still need to define deprecated handlers for compatibility with old TWiki versions. In this case, the plugin package that defines old handlers can suppress the warnings in %FAILEDPLUGINS%.

This is done by defining a map from the handler name to the TWiki::Plugins version in which the handler was first deprecated. For example, if we need to define the endRenderingHandler for compatibility with TWiki::Plugins versions before 1.1, we would add this to the plugin: 

package TWiki::Plugins::SinkPlugin;
use vars qw( %TWikiCompatibility );
$TWikiCompatibility{endRenderingHandler} = 1.1;
If the currently-running TWiki version is 1.1 or later, then the handler will not be called and the warning will not be issued. TWiki with versions of TWiki::Plugins before 1.1 will still call the handler as required.

Related Topics: DeveloperDocumentationCategory, AdminDocumentationCategory, TWiki:TWiki.TWikiPluginsSupplement

-- Contributors: TWiki:Main.PeterThoeny, TWiki:Main.AndreaSterbini, TWiki:Main.MikeMannix, TWiki:Main.CrawfordCurrie, TWiki:Main.ArthurClemens, TWiki:Main.WillNorris
Copyright © 1999-2025 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding Foswiki? Send feedback
Note: Please contribute updates to this topic on TWiki.org at TWiki:TWiki.TWikiPlugins.

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