Documentation of the TWiki Implementation (version TWiki-6.1.0, Mon, 16 Jul 2018, build 30610)

• (1) Wiki Username vs. Login Username
• (2) Wiki Templates
• (3) Wiki Variables
• (4) Notification of Changes by Email
• (5) TWiki Category Table
• (6) Implementation Notes
• (7) Installation Notes
• (8) Upgrading Earlier Versions of TWiki

Related Topics: TWikiWeb, TWikiHistory, TWikiPlannedFeatures, TWikiEnhancementRequests.

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(1) Wiki Username vs. Login Username

Warning: Can't find topic TWiki.TWikiUsernameVsLoginUsername

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(2) Wiki Templates

TWiki Templates

Definition of the templates used to render all HTML pages displayed in TWiki

Overview

Templates are plain text with embedded template directives that tell TWiki how to compose blocks of text together, to create something new.

There are two types of template:

• Master Templates: Define the HTML used to display TWiki pages.
• Template Topics: Define default text when you create a new topic

Tip: TWiki:TWiki.TWikiTemplatesSupplement on TWiki.org has supplemental documentation on TWiki templates.

Master Templates

TWiki uses master templates when composing the output from all actions, like topic view, edit, and preview. This allows you to change the look and feel of all pages by editing just a few template files.

Master templates are also used in the definition of TWikiSkins.

Master templates are stored as text files with the extension .tmpl. They are usually HTML with embedded template directives. The directives are expanded when TWiki wants to generate a user interface screen.

How Template Directives Work

• Directives are of the form %TMPL:<key>% and %TMPL:<key>{"attr"}%.
• Directives:
  • %TMPL:INCLUDE{"file"}%: Includes a template file. The file is found as described below.
  • %TMPL:DEF{"block"}%: Define a block. All text between this and the next %TMPL:END% directive is removed and saved for later use with %TMPL:P.
  • %TMPL:END%: Ends a block definition.
  • %TMPL:P{"var"}%: Includes a previously defined block.
  • %{...}%: is a comment.
• Two-pass processing lets you use a variable before or after declaring it.
• Templates and TWikiSkins work transparently and interchangeably. For example, you can create a skin that overloads only the twiki.tmpl master template, like twiki.print.tmpl, that redefines the header and footer.
• Use of template directives is optional: templates work without them.
• NOTE: Template directives work only for templates: they do not get processed in normal topic text.

TMPL:P also supports simple parameters. For example, given the definition %TMPL:DEF{"x"}% x%P%z%TMPL:END% then %TMPL:P{"x" P="y"}% will expand to xyz.

Note that parameters can simply be ignored; for example, %TMPL:P{"x"}% will expand to x%P%z.

Any alphanumeric characters can be used in parameter names. You are highly recommended to use parameter names that cannot be confused with TWikiVariables.

Note that three parameter names, context, then and else are reserved. They are used to support a limited form of "if" condition that you can use to select which of two templates to use, based on a context identifier:

%TMPL:DEF{"link_inactive"}%<input type="button" disabled value="Link>%TMPL:END%
%TMPL:DEF{"link_active"}%<input type="button" onclick="link()" value="Link" />%TMPL:END%
%TMPL:P{context="inactive" then="inactive_link" else="active_link"}% for %CONTEXT%

When the "inactive" context is set, then this will expand the "link_inactive" template; otherwise it will expand the "link_active" template. See IfStatements for details of supported context identifiers.

Finding Templates

The master templates shipped with a twiki release are stored in the twiki/templates directory. As an example, twiki/templates/view.tmpl is the default template file for the twiki/bin/view script.

You can save templates in other directories as long as they are listed in the {TemplatePath} configuration setting. The {TemplatePath} is defined in the Miscellaneous section of the configure page.

You can also save templates in user topics (IF there is no possible template match in the templates directory). The {TemplatePath} configuration setting defines which topics will be accepted as templates.

Templates that are included with an explicit '.tmpl' extension are looked for only in the templates/ directory. For instance %TMPL:INCLUDE{"example.tmpl"}% will only return templates/example.tmpl, regardless of {TemplatePath} and SKIN settings.

The out-of-the-box setting of {TemplatePath} supports the following search order to determine which template file or topic to use for a particular script or %TMPL:INCLUDE{"script"}% statement. The skin path is set as described in TWikiSkins.

1. templates/web/script.skin.tmpl for each skin on the skin path
   • this usage is supported for compatibility only and is deprecated. Store web-specific templates in TWiki topics instead.
2. templates/script.skin.tmpl for each skin on the skin path
3. templates/web/script.tmpl
   • this usage is supported for compatibility only and is deprecated. Store web-specific templates in TWiki topics instead.
4. templates/script.tmpl
5. The TWiki topic aweb.atopic if the template name can be parsed into aweb.atopic
6. The TWiki topic web.SkinSkinScriptTemplate for each skin on the skin path
7. The TWiki topic web.ScriptTemplate
8. The TWiki topic %SYSTEMWEB%.SkinSkinScriptTemplate for each skin on the skin path
9. The TWiki topic %SYSTEMWEB%.ScriptTemplate

Legend:

• script refers to the script name, e.g view, edit
• Script refers to the same, but with the first character capitalized, e.g View
• skin refers to a skin name, e.g dragon, pattern. All skins are checked at each stage, in the order they appear in the skin path.
• Skin refers to the same, but with the first character capitalized, e.g Dragon
• web refers to the current web

For example, the example template file will be searched for in the following places, when the current web is Thisweb and the skin path is print,pattern:

1. templates/Thisweb/example.print.tmpl deprecated; don't rely on it
2. templates/Thisweb/example.pattern.tmpl deprecated; don't rely on it
3. templates/example.print.tmpl
4. templates/example.pattern.tmpl
5. templates/Thisweb/example.tmpl deprecated; don't rely on it
6. templates/example.tmpl
7. Thisweb.PrintSkinExampleTemplate
8. Thisweb.PatternSkinExampleTemplate
9. Thisweb.ExampleTemplate
10. TWiki.PrintSkinExampleTemplate
11. TWiki.PatternSkinExampleTemplate
12. TWiki.ExampleTemplate

Template names are usually derived from the name of the currently executing script; however it is also possible to override these settings in the view and edit scripts, for example when a topic-specific template is required. Two preference variables can be used to override the templates used:

• VIEW_TEMPLATE sets the template to be used for viewing a topic
• EDIT_TEMPLATE sets the template for editing a topic.

If these preferences are set locally (using Local instead of Set) for a topic, in WebPreferences, in Main.TWikiPreferences, or TWiki.TWikiPreferences (using Set), the indicated templates will be chosen for view and edit respectively. The template search order is as specified above.

Both VIEW_TEMPLATE and EDIT_TEMPLATE may contain TWiki variables, which are expanded. For example, the following setting causes Item* topics to be displayed with the custom view template ItemViewTmpl while the other topics are displayed normally.

   * Set VIEW_TEMPLATE = %IF{"'%CALCULATE{$SUBSTRING(%TOPIC%, 1, 4)}%' = 'Item'" then="ItemViewTmpl"}%

The following setting causes Item* topics to be edited with the editform template (edits only the TWiki form of the topic without editing the topic text) while the other topics are edited normally.

   * Set EDIT_TEMPLATE = %IF{"'%CALCULATE{$SUBSTRING(%TOPIC%, 1, 4)}%' = 'Item'" then="editform"}%

Tip: If you want to override existing templates, without having to worry that your changes will get overwritten by the next TWiki update, change the {TemplatePath} so that another directory, such as the %USERSWEB% appears at the front. You can then put your own templates into that directory or web and these will override the standard templates. (Note that such will increase the lookup time for templates by searching your directory first.)

TMPL:INCLUDE recursion for piecewise customization, or mixing in new features

If there is recursion in the TMPL:INCLUDE chain (eg twiki.classic.tmpl contains %TMPL:INCLUDE{"twiki"}%, the templating system will include the next twiki.SKIN in the skin path. For example, to create a customization of pattern skin, where you only want to over-ride the breadcrumbs for the view script, you can create only a view.yourlocal.tmpl:

%TMPL:INCLUDE{"view"}%
%TMPL:DEF{"breadcrumb"}% We don't want any crumbs %TMPL:END%

and then set SKIN=yourlocal,pattern

The default {TemplatePath} will not give you the desired result if you put these statements in the topic Thisweb.YourlocalSkinViewTemplate. The default {TemplatePath} will resolve the request to the template/view.pattern.tmpl, before it gets to the Thisweb.YourlocalSkinViewTemplate resolution. You can make it work by prefixing the {TemplatePath} with: $web.YourlocalSkin$nameTemplate.

Default master template

twiki.tmpl is the default master template. It defines the following sections.

Template variable:	Defines:
%TMPL:DEF{"sep"}%	"|" separator
%TMPL:DEF{"htmldoctype"}%	Start of all HTML pages
%TMPL:DEF{"standardheader"}%	Standard header (ex: view, index, search)
%TMPL:DEF{"simpleheader"}%	Simple header with reduced links (ex: edit, attach, oops)
%TMPL:DEF{"standardfooter"}%	Footer, excluding revision and copyright parts

Template Topics

The second type of template in TWiki are template topics. Template topics define the default text for new topics. There are four types of template topic:

Topic Name:	What it is:
WebTopicViewTemplate	Alert page shown when you try to view a nonexistent topic. This page is usually used as a prompt to help you create a new topic.
WebTopicNonWikiTemplate	Alert page shown when you try to view a nonexistent topic with a non-WikiName. Again, this page is used as a prompt to help you create the new topic.
WebTopicEditTemplate	Default text used in a new topic.
<MyCustomNamed>Template	Whenever you create a topic ending in the word "Template", it is automatically added to the list of available templates in the "Use Template" drop down field on the WebCreateNewTopic page.

When you create a new topic using the edit script, TWiki locates a topic to use as a content template according to the following search order:

1. A topic name specified by the templatetopic CGI parameter
   • if no web is specified, the current web is searched first and then the TWiki web
2. WebTopicEditTemplate in the current web
3. WebTopicEditTemplate in the Main web
4. WebTopicEditTemplate in the TWiki web

Variable Expansion

TWikiVariables located in template topics get expanded as follows when a new topic is created.

1. Default variable expansion

The following variables used in a template topic automatically get expanded when new topic is created based on it:

Variable:	Description:
%DATE%	Signature format date. See VarDATE
%GMTIME%	Date/time. See VarGMTIME
%GMTIME{...}%	Formatted date/time. See VarGMTIME2
%NOP%	A no-operation variable that gets removed. Useful to prevent a SEARCH from hitting an edit template topic; also useful to escape a variable, such as %URLPA%NOP%RAM{...}% escaping URLPARAM
%STARTSECTION{type="templateonly"}% ... %ENDSECTION{type="templateonly"}%	Text that gets removed when a new topic based on the template is created. See notes below.
%SERVERTIME%	Date/time. See VarSERVERTIME
%SERVERTIME{...}%	Formatted date/time. See VarSERVERTIME2
%USERNAME%	Login name of user who is instantiating the new topic, e.g. guest
%URLPARAM{"name"}%	Value of a named URL parameter. See VarURLPARAM.
%WIKINAME%	WikiName of user who is instantiating the new topic, e.g. TWikiGuest
%WIKIUSERNAME%	User name of user who is instantiating the new tpoic, e.g. Main.TWikiGuest

2. Preventing variable expansion

In a template topic, embed text that you do not want expanded inside a %STARTSECTION{type="templateonly"}% ... %ENDSECTION{type="templateonly"}% section. For example, you might want to write this in the template topic:

%STARTSECTION{type="templateonly"}%
This template can only be changed by:
   * Set ALLOWTOPICCHANGE = Main.TWikiAdminGroup
%ENDSECTION{type="templateonly"}%

This will restrict who can edit the template topic, but will be removed when a new topic based on that template topic is created.

%NOP% can be used to prevent expansion of TWiki variables that would otherwise be expanded during topic creation. For example, escape %SERVERTIME% with %SER%NOP%VERTIME%.

3. Causing variable expansion in a section

You can forcefully expand TWikiVariables by placing them inside a type="expandvariables" section in the template topic, such as:

 ...  

Example:

If you have the following content in a template topic:

   * %SYSTEMWEB%.ATasteOfTWiki - view a short introductory presentation on TWiki for beginners
   * %SYSTEMWEB%.WelcomeGuest - starting points on TWiki
   * %SYSTEMWEB%.TWikiUsersGuide - complete TWiki documentation
   * Sandbox.%HOMETOPIC% - try out TWiki on your own
   * Sandbox.%TOPIC%Sandbox - just for me

you will get this raw text in new topics based on that template topic:

   * TWiki.ATasteOfTWiki - view a short introductory presentation on TWiki for beginners
   * TWiki.WelcomeGuest - starting points on TWiki
   * TWiki.TWikiUsersGuide - complete TWiki documentation
   * Sandbox.WebHome - try out TWiki on your own
   * Sandbox.JimmyNeutronSandbox - just for me

4. Specifying variables to be expanded individually

You may want to mix variables to be expanded and variables not to be. By prepending a variable name with EOTC__ (EOTC followed by two underscores; EOTC stands for Expand On Topic Creation), you can have the variable expanded.

Here's an example.

%EOTC__SEARCH{"."
 topic="%URLPARAM{prefix}%*"
 nonoise="on"
 format="$percntINCLUDE{$topic}$percnt" separator="$n"
}%

This yields a series of %INCLUDE{...}%s, which are not expanded. This is not achievable by an expandvariables section.

Specifying a Form

When you create a new topic based on a template, you often want the new topic to have a form attached to it. You can attach a form to the template topic, in which case it will be copied into the new topic.

Sometimes this isn't quite what you want, as it copies all the existing data from the template topic into the new topic. To avoid this and use the default values specified in the form definition instead, you can use the formtemplate CGI parameter to the edit script to specify the name of a form to attach.

See TWikiScripts for information about all the other parameters to edit.

Automatically Generated Unique Topic Names

For TWiki applications it is useful to be able to automatically generate unique topic names, such as BugID0001, BugID0002, etc. You can add AUTOINC<n> to the topic name in the edit and save scripts, and it will be replaced with an auto-incremented number on topic save. <n> is a number starting from 0, and may include leading zeros. Leading zeros are used to zero-pad numbers so that auto-incremented topic names can sort properly. Deleted topics are not re-used to ensure uniqueness of topic names. That is, the auto-incremented number is always higher than the existing ones, even if there are gaps in the number sequence.

Examples:

• BugAUTOINC0 - creates topic names Bug0, Bug1, Bug2, ... (does not sort properly)
• ItemAUTOINC0000 - creates topic names Item0000, Item0001, Item0002, ... (sorts properly up to 9999)
• DocIDAUTOINC10001 - start with DocID10001, DocID10002, ... (sorts properly up to 99999; auto-links)

Characters after AUTOINC<n> are preserved, but are not taken into account when calculating the next increment. Use this to create topic names that have a unique identifier (serial number) and a descriptive text.

Example:

• BlogAUTOINC0001-my-first-blog - creates topic name Blog0001-my-first-blog
• BlogAUTOINC0001-my-crazy-cats - creates topic name Blog0002-my-crazy-cats
• BlogAUTOINC0001-fondue-recipe - creates topic name Blog0003-fondue-recipe

Example link to create a new topic:

[[%SCRIPTURLPATH{edit}%/%WEB%/BugIDAUTOINC00001?templatetopic=BugTemplate;topicparent=%TOPIC%;t=%SERVERTIME{"$day$hour$min$sec"}%][Create new item]]

Note: After the save operation, the web client is redirected to the newly created topic by default. If the specified topic name contains AUTOINC<n> and you want to redirect to a different URL containing the newly created topic's name, you can use AUTOINC in the redirectto parameter. Let's say the specified topic name is ItemAUTOINC0001, and redirectto is set to %SCRIPTURL{view}%/%WEB%/ViewerTopic?id=ItemAUTOINC. If the latest existing topic is Item0123, a new topic named Item0124 is created, and the web client is redirected to ViewerTopic?id=Item0124 in the current web.

Template Topics in Action

Here is an example for creating new topics (in the Sandbox web) based on a specific template topic and form:

• New example topic:

The above form asks for a topic name. A hidden input tag named templatetopic specifies ExampleTopicTemplate as the template topic to use. Here is the raw text of the form:

%EDITFORMFIELD{ "new" type="start" action="edit" topic="Sandbox.%TOPIC%" }%
   * New example topic: 
     %EDITFORMFIELD{ "topic" type="text" value="ExampleTopicAUTOINC0001" size="30" }%
     %EDITFORMFIELD{ "templatetopic" type="hidden" value="%SYSTEMWEB%.ExampleTopicTemplate" }%
     %EDITFORMFIELD{ "topicparent" type="hidden" value="%HOMETOPIC%" }%
     %EDITFORMFIELD{ "onlywikiname" type="hidden" value="on" }%
     %EDITFORMFIELD{ "onlynewtopic" type="hidden" value="on" }%
     %EDITFORMFIELD{ "form" type="submit" value="Create" }%
%EDITFORMFIELD{ "form" type="end" }%

Here is the equivalent form using a hand-crafted HTML form:

<form name="new" action="%SCRIPTURLPATH{edit}%/Sandbox/%HOMETOPIC%">
   * New example topic: 
     <input type="text" name="topic" value="ExampleTopicAUTOINC0001" size="30" />
     <input type="hidden" name="templatetopic" value="%SYSTEMWEB%.ExampleTopicTemplate" />
     <input type="hidden" name="topicparent" value="%HOMETOPIC%" />
     <input type="hidden" name="onlywikiname" value="on" />
     <input type="hidden" name="onlynewtopic" value="on" />
     <input type="submit" class="twikiSubmit" value="Create" />
</form>

Note: You can create a topic in one step, without going through the edit screen. To do that, specify the save script instead of the edit script in the form action. When you specify the save script in an HTML form tag you have to use the "post" method. This is done automatically when using the EDITFORMFIELD variable. Example when using the HTML form tag:

<form name="new" action="%SCRIPTURLPATH{save}%/Sandbox/" method="post">
    ...
</form>

The edit and save scripts understand many more parameters, see TWikiScripts#edit and TWikiScripts#save for details.

TIP: You can use the %WIKIUSERNAME% and %DATE% variables in your topic templates to include the signature of the person creating a new topic. The variables are expanded into fixed text when a new topic is created. The standard signature is:
-- %WIKIUSERNAME% - %DATE%

Using Absolute vs Relative URLs in Templates

When you use TWikiVariables such as %PUBURL% and %PUBURLPATH% in templates you should be aware that using %PUBURL% instead of %PUBURLPATH% puts absolute URLs in the produced HTML. This means that when a user saves a TWiki page in HTML and emails the file to someone outside a company firewall, the receiver has a severe problem viewing it. It is therefore recommended always to use the %PUBURLPATH% to refer to images, CSS, Javascript files etc so links become relative. This way browsers just give up right away and show a usable html file.

Related Topics: TWikiSkins, TWikiForms, TWikiScripts, DeveloperDocumentationCategory, AdminDocumentationCategory

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(3) Wiki Variables

TWiki Variables

Special text strings expand on the fly to display dynamic content, such as user data or system info

TWikiVariables are text strings - %VARIABLE% or %VARIABLE{ parameter="value" }% - that expand into content whenever a topic is rendered for viewing. There are two types of variables:

1. Preferences variables: Can be defined and changed by the user.
   Example: %T% renders as
2. Predefined variables: Defined by the TWiki system or by extensions.
   Example: %CALCULATE{}% is handled by the SpreadSheetPlugin

See list of all TWiki Variables currently defined in this TWiki installation.

TWiki Variables Wizard — to Find and Compose Variables

Categories: all Administration Applications & Components Attachments & Files Charting & Drawing Database & Forms Date & Time Development Editing & Content Update Email & Notification Export & Publishing Formatting & Rendering Import Linking & Navigation Searching & Listing Security & Access Control Skins & Templates System Information Tables & Spreadsheets UI& Visualization Users & Authentication Workflow & Automation

Variables:

Using Variables

To use a variable type its name. For example,

• type %T% to get (a preferences variable)
• type %TOPIC% to get TWikiVariables (a predefined variable)
• type %CALCULATE{ "$UPPER(Text)" }% to get TEXT (a variable defined by a plugin)

Note:

• To leave a variable unexpanded, precede it with an exclamation point, e.g. type !%TOPIC% to get %TOPIC%
• Variables are expanded relative to the topic they are used in, not the topic they are defined in
• Type %ALLVARIABLES% to get a full listing of all variables defined for a particular topic

Variable Names

Variable names must start with a letter, optionally followed by letters, numbers and underscore '_' characters. Both upper-case and lower-case characters can be used, %MYVAR%, %MyVar%, %My2ndVar%, and %My_Var% are valid names. Variables are case sensitive, e.g. %MyVAR% and %MYVAR% are not the same.

By convention all settings, predefined variables and variables handled by extensions are always UPPER-CASE.

Preferences Variables

Unlike predefined variables, preferences variables can be defined by the user in various places.

Setting Preferences Variables

You can set variables in all the following places:

1. system level in TWiki.TWikiPreferences
2. plugin topics (see TWikiPlugins)
3. local site level in Main.TWikiPreferences
4. user level in individual user topics in Main web
   • If UserSubwebs is in effect, the topic specified by %USERPREFSTOPIC% in the user's subweb is read instead
   • If $TWiki::cfg{DemoteUserPreferences} is true, this step is deferred to a later step. On this TWiki installation, $TWiki::cfg{DemoteUserPreferences} is false
5. web level in WebPreferences of each web
6. If EXTRAPREFERENCES is defined at this point, it's regarded as having comma separated list of topics. Those topics are read in the listed order as if they were WebPreferences
7. topic level in topics in webs
8. session variables (if sessions are enabled)
9. user level preferences are set at this point if $TWiki::cfg{DemoteUserPreferences} is true as mentioned at the step 4

Settings at higher-numbered levels override settings of the same variable at lower numbered levels, unless the variable was included in the setting of FINALPREFERENCES at a lower-numbered level, in which case it is locked at the value it has at that level.

If you are setting a variable and using it in the same topic, note that TWiki reads all the variable settings from the saved version of the topic before it displays anything. This means you can use a variable anywhere in the topic, even if you set it somewhere inconspicuous near the end. But beware: it also means that if you change the setting of a variable you are using in the same topic, preview will show the wrong thing, and you must save the topic to see it correctly.

The syntax for setting variables is the same anywhere in TWiki (on its own TWiki bullet line, including nested bullets):
[multiple of 3 spaces] * [space] Set [space] VARIABLENAME [space] = [space] value

Examples:

   * Set VARIABLENAME1 = value
      * Set VARIABLENAME2 = value

Spaces between the = sign and the value will be ignored. You can split a value over several lines by indenting following lines with spaces - as long as you don't try to use * as the first character on the following line.

Example:

   * Set VARIABLENAME = value starts here
     and continues here

Whatever you include in your variable will be expanded on display, exactly as if it had been entered directly.

Example: Create a custom logo variable

• To place a logo anywhere in a web by typing %MYLOGO%, define the Variable on the web's WebPreferences topic, and upload a logo file, ex: mylogo.gif. You can upload by attaching the file to WebPreferences, or, to avoid clutter, to any other topic in the same web, e.g. LogoTopic. Sample variable setting in WebPreferences:

      * Set MYLOGO = %PUBURL%/%WEB%/LogoTopic/mylogo.gif

You can also set preferences variables on a topic by clicking the link Edit topic preference settings under More topic actions. Use the same * Set VARIABLENAME = value syntax. Preferences set in this manner are not visible in the topic text, but take effect nevertheless.

Controlling User Level Preferences Override

By default, user level variables are set at the step 4 as stated in the previous section. That means a user can finalise some preferences variables so that web level or topic level setting cannot override it. This may result in a situation the web or page owner doesn't expect. $TWiki::cfg{DemoteUserPreferences} has been introduced to avoid it. If it's set to true, user level variables are set at the last step instead of the step 4.

But this is not enough. To guarantee a certain result, you need to finalise critical preferences variables set at the web or topic level, which is cumbersome. So preferences variables DENYUSERPREFEENCES and ALLOWUSERPREFERENCES have been introduced.

• DENYUSERPREFEENCES and ALLOWUSERPREFERENCES may have comma separated list of variable names
• If a preferences variable is listed in DENYUSERPREFEENCES, the variable cannot be overridden at the user level. There is a special value "all", which means no preferences variables can be overridden at the user level
• If ALLOWUSERPREFERENCES is set and not empty, only the listed preferences variables can be overridden. There is a special value "all", which means any preferences variable can be overridden at the user level. But actually, "all" is not necessary since a blank value or not setting ALLOWUSERPREFERENCES has the same effect
• DENYUSERPREFEENCES takes precedence over ALLOWUSERPREFERENCES. If a variable is listed on both, it cannot be overridden. If DENYUSERPREFEENCES is "all", the value of ALLOWUSERPREFERENCES doesn't matter.

For example, if you don't allow overriding at the user level at all:

   * Set DENYUSERPREFERENCES = all

If you allow INYMCEPLUGIN_DISABLE and SKIN to be set at the user level:

   * Set ALLOWUSERPREFERENCES = TINYMCEPLUGIN_DISABLE, SKIN

If you allow user preferences to set anything other than TINYMCEPLUGIN_DISABLE or SKIN:

   * Set DENYUSERPREFERENCES = TINYMCEPLUGIN_DISABLE, SKIN

Please note DENYUSERPREFEENCES and ALLOWUSERPREFERENCES affect user preferences regardless of $TWiki::cfg{DemoteUserPreferences}. You can set those variables at the site level while $TWiki::cfg{DemoteUserPreferences} setting to false. If you do so, you should finalise DENYUSERPREFEENCES and ALLOWUSERPREFERENCES. Otherwise, they might be overridden by user preferences.

You will get the most benefit of DENYUSERPREFEENCES and ALLOWUSERPREFERENCES by setting $TWiki::cfg{DemoteUserPreferences} to true. That way, each web can specify how much user level preferences overriding is allowed.

Parameterized Variables (Macros)

It is possible to pass parameters to TWiki variables. This is called a macro in a programming language.

To define a parameterized variable, set a variable that contains other variables, such as:

   * Set EXAMPLE = Example variable using %DEFAULT%, %PARAM1% and %PARAM2%
   * Set DEMO = Demo using %DEFAULT{ default="(undefined)" }%,
                %PARAM1{ default="(undefined)" }% and %PARAM2{ default="(undefined)" }%

A special %DEFAULT% variable denotes the default (nameless) parameter of the calling variable. Variables optionally may list a default="..." parameter that gets used in case the calling variable does not specify that parameter.

To use a parameterized variable (or call a macro), add parameters within the curly brackets, such as:

   * %EXAMPLE{ "foo" PARAM1="bar" PARAM2="baz" }%
   * %DEMO{ "demo" PARAM2="parameter 2" }% -- note that PARAM1 is missing

which resolves to:

• %EXAMPLE{ "foo" PARAM1="bar" PARAM2="baz" }%
• %DEMO{ "demo" PARAM2="parameter 2" }% -- note that PARAM1 is missing

Parameters in the variable definition are expanded using the following sequence:

1. Parameter from variable call. In above example, %PARAM1% gets expanded to bar.
2. Session variable and preferences settings

Example

Define variables:

   * Set DRINK = red wine
   * Set FAVORITE = My %DEFAULT{default="favorite"}% dish is %DISH{default="steak"}%,
                    my %DEFAULT{default="favorite"}% drink is %DRINK%.

The default can be defined with a default parameter (%DISH{default="steak"}%), or as a preferences setting (Set DRINK = ...).

Use Variables:

%FAVORITE{ DISH="Sushi" DRINK="Sake" }%

Returns:
%FAVORITE{ DISH="Sushi" DRINK="Sake" }%

%FAVORITE{}%

Returns:
%FAVORITE{}%

%FAVORITE{ "preferred" }%

Returns:
%FAVORITE{ "preferred" }%

Access Control Variables

These are special types of preferences variables to control access to content. TWikiAccessControl explains these security settings in detail.

Local values for variables

Certain topics (a users home topic, web site and default preferences topics) have a problem; variables defined in those topics can have two meanings. For example, consider a user topic. A user may want to use a double-height edit box when they are editing their home topic - but only when editing their home topic. The rest of the time, they want to have a normal edit box. This separation is achieved using Local in place of Set in the variable definition. For example, if the user sets the following in their home topic:

   * Set EDITBOXHEIGHT = 10
   * Local EDITBOXHEIGHT = 20

Then when they are editing any other topic, they will get a 10 high edit box. However when they are editing their home topic, they will get a 20 high edit box. Local can be used wherever a preference needs to take a different value depending on where the current operation is being performed.

Use this powerful feature with great care! %ALLVARIABLES% can be used to get a listing of the values of all variables in their evaluation order, so you can see variable scope if you get confused.

Frequently Used Preferences Variables

The following preferences variables are frequently used. They are defined in TWikiPreferences#Miscellaneous_Settings:

• %BB% - line break and bullet combined
• %BB2% - level 2 bullet with line break
• %BB3% - level 3 bullet with line break
• %BB4% - level 4 bullet with line break
• %BR% - line break
• %BULLET% - bullet sign
• %CARET% - caret symbol
• %VBAR% - vertical bar
• %H% - Help icon
• %I% - Idea icon
• %M% - Moved to icon
• %N% - New icon
• %P% - Refactor icon
• %Q% - Question icon
• %S% - Pick icon
• %T% - Tip icon
• %U% - Updated icon
• %X% - Alert icon
• %Y% - Done icon
• %RED% text %ENDCOLOR% - colored text (also %YELLOW%, %ORANGE%, %PINK%, %PURPLE%, %TEAL%, %NAVY%, %BLUE%, %AQUA%, %LIME%, %GREEN%, %OLIVE%, %MAROON%, %BROWN%, %BLACK%, %GRAY%, %SILVER%, %WHITE%)
• %REDBG% text %ENDBG% - colored background (also %YELLOWBG%, %ORANGEBG%, %PINKBG%, %PURPLEBG%, %TEALBG%, %NAVYBG%, %BLUEBG%, %AQUABG%, %LIMEBG%, %GREENBG%, %OLIVEBG%, %MAROONBG%, %BROWNBG%, %BLACKBG%, %GRAYBG%, %SILVERBG%, %WHITEBG%)

There are additional useful preferences variables defined in TWikiPreferences, in Main.TWikiPreferences, and in WebPreferences of every web.

Predefined Variables

Most predefined variables return values that were either set in the configuration when TWiki was installed, or taken from server info (such as current username, or date and time). Some, like %SEARCH%, are powerful and general tools.

• Show all TWiki Variables
• Predefined variables can be overridden by preferences variables (except a few such as TOPIC and WEB)
  • This has long been the case but may not be desirable since even something as fundamental as %IF{...}%, %SCRIPT{...}%, and %INCLUDE{...}% can be overridden
  • So TWiki-6.0.1 has introduced a way to protect predefined variables from being overridden by preferences variables
  • The preferences variable OVERRIDABLEPREDEFINEDVARIABLES having a comma separated list of predefined variables specifies which predefined variables are overridable
  • By default, it's set to "all" (set at TWiki.TWikiPreferences), which means any predefined variable can be overridden, which is for compatibility with prior releases. You can set it to a different value in Main.TWikiPreferences and you may finalise it
  • If it's set as below, all predefined variables are protected

       * Set OVERRIDABLEPREDEFINEDVARIABLES =
    

  • If it's set as below, DATE and LANGUAGE predefined variables can be overridden but all the other predefined variables cannot

       * Set OVERRIDABLEPREDEFINEDVARIABLES = DATE, LANGUAGE
    

• Extensions may extend the set of predefined variables (see individual extension topics for details)
• Take the time to thoroughly read through ALL preference variables. If you actively configure your site, review variables periodically. They cover a wide range of functions, and it can be easy to miss the one perfect variable for something you have in mind. For example, see %INCLUDINGTOPIC%, %INCLUDE%, and the mighty %SEARCH%.

Search or List Variables by Category

All TWiki Variables: ACTIVATEDPLUGINS, ADDTOHEAD, ALLVARIABLES, AQUA, ATTACHURL, ATTACHURLPATH, AUTHREALM, BASETOPIC, BASEWEB, BB, BB2, BB3, BB4, BLACK, BLUE, BR, BROWN, BUBBLESIG, BULLET, CALC, CALCULATE, CARET, CHILDREN, COLORPICKER, COMMENT, CONTENTMODE, COPY, DASHBOARD, DATE, DATEPICKER, DISPLAYTIME, DISPLAYTIME2, EDITACTION, EDITFORM, EDITFORMFIELD, EDITTABLE, ENCODE, ENDBG, ENDCOLOR, ENDCOLUMNS, ENDSECTION, ENTITY, ENV, EXAMPLEVAR, FAILEDPLUGINS, FORM, FORMFIELD, FOURCOLUMNS, GET, GMTIME, GMTIME2, GRAY, GREEN, GROUPS, H, HEADLINES, HIDE, HIDEINPRINT, HOMETOPIC, HTTP, HTTPHOST, HTTPS, I, ICON, ICONURL, ICONURLPATH, IF, INCLUDE, INCLUDINGTOPIC, INCLUDINGWEB, JQENDTAB, JQENDTABPANE, JQTAB, JQTABPANE, LANGUAGE, LANGUAGES, LAQUO, LIME, LOCALSITEPREFS, LOGIN, LOGINURL, LOGOUT, LOGOUTURL, M, MAINWEB, MAKETEXT, MAROON, MDREPO, META, METASEARCH, N, NAVY, NBSP, NOP, NOTIFYTOPIC, OLIVE, ORANGE, P, PARENTBC, PARENTTOPIC, PINK, PLUGINDESCRIPTIONS, PLUGINVERSION, PUBURL, PUBURLPATH, PURPLE, Q, QUERYPARAMS, QUERYSTRING, RAQUO, RED, REDBG, REG, REMOTEADDR, REMOTEPORT, REMOTEUSER, RENDERLIST, REVINFO, REVINFO2, S, SCRIPTNAME, SCRIPTSUFFIX, SCRIPTURL, SCRIPTURL2, SCRIPTURLPATH, SCRIPTURLPATH2, SEARCH, SERVERTIME, SERVERTIME2, SESSIONID, SESSIONVAR, SESSIONVARIABLE, SET, SETGETDUMP, SILVER, SITENAME, SITESTATISTICSTOPIC, SLIDESHOWEND, SLIDESHOWSTART, SPACEDTOPIC, SPACEOUT, STARTINCLUDE, STARTSECTION, STATISTICSTOPIC, STOPINCLUDE, SYSTEMWEB, T, TABLE, TEAL, THREECOLUMNS, TM, TOC, TOC2, TOPIC, TOPICLIST, TOPICTITLE, TOPICURL, TWIKISHEET, TWIKIWEB, TWISTY, TWOCOLUMNS, U, URLPARAM, USERINFO, USERNAME, USERREPORT, USERSIG, USERSWEB, VAR, VBAR, WEB, WEBLIST, WEBPREFSTOPIC, WHITE, WIKIHOMEURL, WIKILOGOALT, WIKILOGOIMG, WIKILOGOURL, WIKINAME, WIKIPREFSTOPIC, WIKITOOLNAME, WIKIUSERNAME, WIKIUSERSTOPIC, WIKIVERSION, WIKIWEBMASTER, WIKIWEBMASTERNAME, WIP, X, Y, YELLOW, total 190 variables

Documenting TWiki Variables

This section is for people documenting TWiki variables of the TWiki core and TWiki extensions.

Each variable is documented in a topic named Var<name> in the TWiki web. For example, a %LIGHTSABER% variable has a documentation topic called VarLIGHTSABER. The topic is expected to have a specific format so that reports in this TWikiVariables topic, in TWikiVariablesSearch and in category topics work as expected.

Basic structure of a variable documentation topic:

• Parent set to TWikiVariables
• An anchor named the same like the topic, such as #VarLIGHTSABER
• A ---+++ (level 3) heading with variable name, --, short description
• A bullet with description of the variable (optional)
• A Syntax: bullet with example syntax
• A Parameters: bullet with a table explaining the parameters (optional)
• An Example: bullet or two with examples
• An Expands to: bullet with expanded variable (optional)
• A Note: bullet with notes (optional)
• A Category: bullet with one or more of the TWiki variables categories:
  AdministrationVariables, ApplicationsAndComponentsVariables, AttachmentsAndFilesVariables, ChartingAndDrawingVariables, DatabaseAndFormsVariables, DateAndTimeVariables, DevelopmentVariables, EditingAndContentUpdateVariables, EmailAndNotificationVariables, ExportAndPublishingVariables, FormattingAndRenderingVariables, ImportVariables, LinkingAndNavigationVariables, SearchingAndListingVariables, SecurityAndAccessControlVariables, SkinsAndTemplatesVariables, SystemInformationVariables, TablesAndSpreadsheetsVariables, UIAndVisualizationVariables, UsersAndAuthenticationVariables, WorkflowAndAutomationVariables
• A Related: bullet with related links. Links have conditional IF so that links work properly locally in variable documentation topics and in the TWikiVariables topic

Example content of a VarLIGHTSABER topic:

#VarLIGHTSABER
---+++ LIGHTSABER -- laser sword to fend of unethical competition
   * The =%<nop>LIGHTSABER{}%= variable is handled by the LightsaberPlugin.
   * Syntax: =%<nop>LIGHTSABER{ _parameters_ }%=
   * Parameters:
     | *Parameter* | *Description* | *Default* |
     | =color="..."= | Color: =red=, =glue=, =green= | =white= |
     | =sound="..."= | Sound: =none=, =standard=, =loud= | =none= |
   * Example: =%<nop>LIGHTSABER{ color="red" }%= shows a red Lightsaber
   * Expands to: =%LIGHTSABER{ color="red" }%=
   * Note: The Lightsaber is a fictional weapon in the Star Wars universe, a "laser sword."
   * Category: FormattingAndRenderingVariables, UIAndVisualizationVariables
   * Related: [[%IF{"'%INCLUDINGTOPIC%'='TWikiVariables'" then="#"}%VarPLASMA][PLASMA]], LightsaberPlugin

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(4) Notification of Changes by Email

Warning: Can't find topic TWiki.TWikiNotificationOfChanges

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(5) TWiki Category Table

Warning: Can't find topic TWiki.TWikiCategoryTable

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(6) Implementation Notes

Warning: Can't find topic TWiki.TWikiImplementation

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(7) Installation Notes

Warning: Can't find topic TWiki.TWikiInstallationNotes

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(8) Upgrading Earlier Versions of TWiki

Warning: Can't find topic TWiki.TWikiUpgradeNotes