Documentation of the TWiki Implementation (version 04 Sep 2004 $Rev: 1742 $)

Note: Read the most up to date version of this document at http://TWiki.org/cgi-bin/view/TWiki/TWikiDocumentation

Related Topics: TWikiWeb?, TWikiHistory, TWikiPlannedFeatures, TWikiEnhancementRequests.


TWiki System Requirements

Server and client system requirements for TWiki 01-Sep-2001

Overview

Maintaining minimum client and server requirements is necessary to keep TWiki deployment as broad as possible.

Server Requirements

TWiki is written in Perl 5, uses a number of shell commands, and requires RCS (Revision Control System), a GNU Free Software package. TWiki is developed in a basic Linux/Apache environment. It also works with Microsoft Windows, and should have no problem on any other platform that meets the requirements:

Required Server Environment
Resource Unix Windows
Perl 5.005_03 or higher
Non standard Perl modules Net::SMTP (or sendmail) Net::SMTP, MIME::Base64, Digest::SHA1
RCS 5.7 or higher
Other external programs ls, fgrep, egrep
Web server Apache; others (with support for CGI, authentication, extended path) *

Current documentation covers Linux only. A TWikiOnWindows installation guide is next.

Client Requirements

The TWiki standard installation has extremely low browser requirements:

You can easily add capabilities, through customizing the templates, for one, while tailoring the browser requirements to your situation.

Known Issues

-- MikeMannix - 15 Sep 2001





TWiki Username vs. Login Username

This section applies only if your netfrag.org is installed on a server that is both authenticated and on an intranet.

netfrag.org internally manages two usernames: Login username and TWiki username.

netfrag.org can map the intranet username to the Wiki username automatically, provided that the Login username and Wiki username pair has been entered in the TWikiUsers topic. This happens automatically when you register.

NOTE: To correctly enter a WikiName - your own or someone else's - be sure to specify the Main web in front of the Wiki username: write Main.WikiUsername or %MAINWEB%.WikiUsername. This assures that the name will be linked automatically to the netfrag.org.Main web, where user registration pages are stored, even if the text is entered in a different netfrag.org web.

-- PeterThoeny - 16 May 2001


TWiki Access Control

Restricting read and write access to topics and webs, by users and groups

Overview

TWikiAccessControl allows you restrict access to single topics and entire webs, by individual user and by user groups, in three main areas: view; edit & attach; and rename/move/delete. These controls, combined with TWikiUserAuthentication, let you easily create and manage an extremely flexible, fine-grained privilege system.

An Important Control Consideration

Open, freeform editing is the essence of the WikiCulture - it's what makes TWiki different and often more effective than other collaboration tools. So, it is strongly recommended that decisions to restrict read or write access to a web or a topic are made with care. Experience shows that unrestricted write access works very well because:

As a collaboration guideline:

Users and Groups

Access control is based on users and groups. Users are defined by their WikiNames, an then organized into unlimited combinations under different user groups.

Managing Users

A user is created by with the TWikiRegistration form. The process generates a topic in the Main web in the new user's WikiName. The default visitor name is TWikiGuest?.

Managing Groups

Groups are defined by group topics in the Main web, like the TWikiAdminGroup. To start a new group:

  1. Create a new topic with A name that ends in Group, SomeGroup
  2. Define two variables:
    • Set GROUP = < list of users and groups >
    • Set ALLOWTOPICCHANGE = < list of users and groups >

Restricting Write Access

You can define who is allowed to make changes to a web or a topic.

Deny Editing by Topic

Denying editing of a topic also restricts attaching files to it; both privileges are assigned together.

Deny Editing by Web

Restricting web-level editing blocks creating new topics, changing topics or attaching files.

The same rules apply as for restricting topics, with these additions:

Restricting Rename Access

You can define who is allowed to rename, move or delete a topic, or rename a web.

Deny Renaming by Topic

To allow a user to rename, move or delete a topic, they also need write (editing) permission. They also need write access to change references in referring topics.

Deny Renaming by Web

You can define restrictions of who is allowed to rename a netfrag.org web.

The same rules apply as for topics, with these additions:

Restricting Read Access

You can define restrictions of who is allowed to view a netfrag.org web.

Known Issues

Selective Unrestricted Web Access

Hiding Control Settings

<!--
Set DENYTOPICCHANGE = Main.SomeGroup
-->

The SuperAdminGroup

By mistyping a user or group name in the ALLOWTOPICCHANGE setting, it's possible to lock a topic so that it no-one can edit it from a browser. To avoid this:

$superAdminGroup = "TWikiAdminGroup";

-- MikeMannix? - 02 Dec 2001


TWiki Templates

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

Overview

The new modular template system offers flexible, easy control over the layout of all TWiki pages. The master template approach groups parts that are shared by several templates - like headers and footers - in a common file. Special variables allow individual layouts to include parts from a master template - variables are mixed with regular HTML mark-up for template-specific content. Templates are used to define page layout, and also to supplydefault content for new pages.

Major changes from the previous template system

Where the old templates were each complete HTML documents, the new templates are defined using variables to include template parts from a master file. You can now change one instance of a common element to update all occurrences; previously, every affected template had to be updated. This simplifies the conversion of templates into XHTML format, and provides a more versatile solution for templates and for TWikiSkins. The new system:

Functional Specifications

TWiki Master Template

All common parts are defined in a master template, twiki.tmpl, that all other templates use.

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

Types of Template

There are two types of templates:

HTML Page Templates

netfrag.org uses HTML template files for all actions like topic view, edit, preview and so on. This allows you to change the look and feel of all pages by editing just some template files.

The template files are in the twiki/templates directory. As an example, twiki/templates/view.tmpl is the template file for the twiki/bin/view script. Templates can be overloaded per web. The following search order applies:

  1. twiki/templates/$webName/$scriptName.tmpl
  2. twiki/templates/$scriptName.tmpl

Note: $webName is the name of the web (ex: Main), and $scriptName is the script (ex: view).

Note: TWikiSkins can be defined to overload the standard templates.

Special variables are used in templates, especially in view, to display meta data.

Template Topics

Template topics define the default text for new topics. There are three types of template topics:

Topic Name: What it is:
WebTopicViewTemplate Help text shown when you view a non existing topic.
WebTopicNonWikiTemplate Help text shown when you view a non existing topic that has not a WikiName.
WebTopicEditTemplate Default text shown when you create a new topic.
All template topics are located in the TWiki web. The WebTopicEditTemplate can be overloaded. The following search order applies when you create a new topic:

  1. The topic name specified by the templatetopic CGI parameter.
  2. WebTopicEditTemplate in the current web.
  3. WebTopicEditTemplate in the TWiki web.

Template Topics in Action

Here is an example for creating new topics based on a specific template topic:

Above form asks for a topic name. A hidden input tag of name "templatetopic" specifies the ExampleTopicTemplate as the template topic. Here is the HTML source of the form:

<form name="new" action="%SCRIPTURLPATH%/edit%SCRIPTSUFFIX%/%WEB%/">
   * New example topic: 
     <input type="text" name="topic" value="ExampleTopic%SERVERTIME{$yearx$mox$day}%" size="23" />
     <input type="hidden" name="templatetopic" value="ExampleTopicTemplate" />
     <input type="hidden" name="onlywikiname" value="on" />
     <input type="submit" value="Create" />
     (date format is <nop>YYYYxMMxDD)
</form>

The "onlywikiname" parameter enforces WikiWords for topic names.

Note: Use can use the %WIKIUSERNAME% and %DATE% variables in your topic templates as the signature; those variables are expanded when a new topic is created. The standard topic signature is:
-- %WIKIUSERNAME% - %DATE%

Templates by Example

Attached is an example of an oops base template oopsbase.tmpl and a example oops dialog oopstest.tmpl which is based on the base template. NOTE: This isn't the release version, just a quick, simple demo.

Base template oopsbase.tmpl

The first line declares the delimiter variable called "sep", used to separate multiple link items. The variable can be called anywhere by writing %TMPL:P{"sep"}%

%TMPL:DEF{"sep"}% | %TMPL:END%
<html>
<head>
  <title> %WIKITOOLNAME% . %WEB% . %TOPIC% %.TMPL:P{"titleaction"}%</title>
  <base href="%SCRIPTURL%/view%SCRIPTSUFFIX%/%WEB%/%TOPIC%">
  <meta name="robots" content="noindex">
</head>
<body bgcolor="#FFFFFF">
<table width="100%" border="0" cellpadding="3" cellspacing="0">
  <tr>
    <td bgcolor="%WEBBGCOLOR%" rowspan="2" valign="top" width="1%">
      <a href="%WIKIHOMEURL%">
      <img src="%PUBURLPATH%/wikiHome.gif" border="0"></a>
    </td>
    <td>
      <b>%WIKITOOLNAME% . %WEB% . </b><font size="+2">
      <B>%TOPIC%</b> %TMPL:P{"titleaction"}%</font>
    </td>
  </tr>
  <tr bgcolor="%WEBBGCOLOR%">
    <td colspan="2">
      %TMPL:P{"webaction"}%
    </td>
  </tr>
</table>
--- ++ %TMPL:P{"heading"}%
%TMPL:P{"message"}%
<table width="100%" border="0" cellpadding="3" cellspacing="0">
  <tr bgcolor="%WEBBGCOLOR%">
    <td valign="top">
      Topic <b>%TOPIC%</b> . {
        %TMPL:P{"topicaction"}%
      }
    </td>
  </tr>
</table>
</body>

Test template oopstest.tmpl

Each oops template basically just defines some variables and includes the base template that does the layout work.

%TMPL:DEF{"titleaction"}% (test =titleaction=) %TMPL:END%
%TMPL:DEF{"webaction"}% test =webaction= %TMPL:END%
%TMPL:DEF{"heading"}%
Test heading %TMPL:END%
%TMPL:DEF{"message"}%
Test =message=. Blah blah blah blah blah blah blah blah blah blah blah...

   * Some more blah blah blah blah blah blah blah blah blah blah...
   * Param1: %PARAM1%
   * Param2: %PARAM2%
   * Param3: %PARAM3%
   * Param4: %PARAM4%
%TMPL:END%
%TMPL:DEF{"topicaction"}%
Test =topicaction=:
[[%WEB%.%TOPIC%][OK]] %TMPL:P{"sep"}%
[[%TWIKIWEB%.TWikiRegistration][Register]] %TMPL:END%
%TMPL:INCLUDE{"oopsbase"}%

Sample screen shot of oopstest.tmpl

With URL: .../bin/oops/Test/TestTopic2?template=oopstest&param1=WebHome&param2=WebNotify

testscreen.gif

Known Issues

-- PeterThoeny - 23 Jul 2001
-- MikeMannix - 14 Sep 2001


TWiki Skins

Skins overlay regular templates with alternate header/footer layouts; topic text is not affected

Overview

Skins are customized TWikiTemplates files. You can use skins to change the look of a netfrag.org topic, for example, the layout of the header and footer. Rendered text between header and footer does not change. You can also use skins to define an alternate view, like a view optimized for printing.

Defining Skins

Skin files are located in the twiki/templates directory and are named with the syntax: <scriptname>.<skin>.tmpl. For example, the Printable skin for the view template is view.print.tmpl.

Activating Skins

A skin can be activated in two ways:

The ?skin=name URL parameter overrides the SKIN Preference value.

-- PeterThoeny - 14 Jul 2001


TWiki Variables

Text strings expanded on the fly to display data or system info

Overview

TWikiVariables are text strings - %VARIABLE% - that expand into content whenever a page is opened. Variables are replaced by their actual values: stored data, or system info (like the date, or the current user). There are predefined variables, and Preference variables that you set. You can also define custom variables, with new names and values.

Predefined Variables

Most predefined variables return values that were either defined when TWiki was installed, or taken from server info (like current username, or date and time). Many of the variables let you control how the formatted results appear.

netfrag.org expands the following variables (enclosed in % percent signs):

Variable: Expanded to:
%WIKIHOMEURL% The base script URL of netfrag.org, is the link of the Home icon in the upper left corner, is http://TWiki.org/
%SCRIPTURL% The script URL of netfrag.org, is http://netfrag.org/twiki/bin
%SCRIPTURLPATH% The path of the script URL of netfrag.org, is /twiki/bin
%SCRIPTSUFFIX% The script suffix, ex: .pl, .cgi is
%PUBURL% The public URL of TWiki, is http://netfrag.org/twiki/pub
%PUBURLPATH% The path of the public URL of netfrag.org, is /twiki/pub
%ATTACHURL% The attachment URL of the current topic, is http://netfrag.org/twiki/pub/TWiki/TWikiVariables
Example: If you attach a file you can refer to it as %ATTACHURL%/image.gif
%ATTACHURLPATH% The path of the attachment URL of the current topic, is /twiki/pub/TWiki/TWikiVariables
%URLPARAM{"name"}% Returns the value of a URL parameter. Ex: %URLPARAM{"skin"}% returns print for a .../view/TWiki/TWikiVariables?skin=print URL. Is
%WIKITOOLNAME% Name of wiki tool, is netfrag.org
%WIKIVERSION% Wiki tool version is 04 Sep 2004 $Rev: 1742 $
%USERNAME% Your login username is guest
%WIKINAME% Your Wiki username. Same as %USERNAME% if not defined in the TWikiUsers topic. Is TWikiGuest
%WIKIUSERNAME% Your %WIKINAME% including the Main web name. Usefull for signatures. Is Main.TWikiGuest
%MAINWEB% The Main web containing TWikiUsers, OfficeLocations? and TWikiGroups?. Is Main
%TWIKIWEB% The web containing all documentation and configuration of netfrag.org is TWiki
%WEB% The current web is TWiki
%BASEWEB% The web name where the includes started, e.g. the web of the first topic of nested includes. Same as %WEB% in case there is no include.
%INCLUDINGWEB% The web name of the topic that includes the current topic. Same as %WEB% in case there is no include.
%HOMETOPIC% The home topic in each web. Is Home?
%NOTIFYTOPIC% The notify topic in each web. Is WebNotify
%WIKIUSERSTOPIC% The index topic of all registered users. Is TWikiUsers
%WIKIPREFSTOPIC% The web preferences topic. Is TWikiPreferences
%WEBPREFSTOPIC% The web preferences topic. Is WebPreferences
%STATISTICSTOPIC% The web statistics topic. Is WebStatistics
%TOPIC% The current topic name, is TWikiVariables
%BASETOPIC% The name of the topic where the includes started, e.g. the first topic of nested includes. Same as %TOPIC% in case there is no include.
%INCLUDINGTOPIC% The name of the topic that includes the current topic. Same as %TOPIC% in case there is no include.
%SPACEDTOPIC% The current topic name with added spaces, for regular expression search of Ref-By, is TWiki%20*Variables
%TOPICLIST{"format"}% Topic index of a web. The "format" defines the format of one topic item. It may include variables: The $name variable gets expanded to the topic name; the $web variable gets expanded to the name of the web. Parameters are format, separator and web:
Parameter: Description: Default:
"format" Format of one line, may include $name and $web variables "$name"
format="format" (Alternative to above) "$name"
separator=", " line separator "\n" (new line)
web="Name" Name of web Current web
Examples:
%TOPICLIST{"   * $web.$name"}% creates a bullet list of all topics.
%TOPICLIST{separator=", "}% creates a comma separated list of all topics.
%TOPICLIST{" <option>$name</option>"}% creates an option list (for drop down menus).
%WEBLIST{"format"}% Web index, e.g. list of all webs. Hidden webs are excluded, e.g. webs with a NOSEARCHALL=on preference variable. The "format" defines the format of one web item. The $name variable gets expanded to the name of the web, $qname gets expanded to double quoted name, $marker to marker where web matches selection. Parameters are format, separator and web:
Parameter: Description: Default:
"format" Format of one line, may include $name variable "$name"
format="format" (Alternative to above) "$name"
separator=", " line separator "\n" (new line)
webs="public" comma sep list of Web, public expands to all non-hidden "public"
marker="selected" Text for $marker where item matches selection, otherwise equals "" "selected"
selection="%WEB%" Current value to be selected in list section="%WEB%"
Examples:
%WEBLIST{"   * [[$name.Home]]"}% creates a bullet list of all webs.
%WEBLIST{"" webs="Trash,public" selection="TWiki" separator=" "}% Dropdown of all public Webs + Trash Web, current Web highlighted.
%GMTIME% GM time, is 28 Mar 2024 - 09:16
%GMTIME{"format"}% Formatted GM time based on time variables.
Variable: Unit: Example
$seconds seconds 59
$minutes minutes 59
$hours hours 23
$day day of month 31
$month month in ISO format Dec
$mo 2 digit month 12
$year 4 digit year 1999
$ye 2 digit year 99
Variables can be shortened to 3 characters. Example:
%GMTIME{"$day $month, $year - $hour:$min:$sec"}% is
28 Mar, 2024 - 09:16:44
%SERVERTIME% Server time, is 28 Mar 2024 - 10:16
%SERVERTIME{"format"}% Formatted server time.
Example: %SERVERTIME{"$hou:$min"}% is 10:16
%HTTP_HOST% HTTP_HOST environment variable, is netfrag.org
%REMOTE_ADDR% REMOTE_ADDR environment variable, is 34.204.52.16
%REMOTE_PORT% REMOTE_PORT environment variable, is 38178
%REMOTE_USER% REMOTE_USER environment variable, is
%INCLUDE{"page" ...}% Server side include to IncludeTopicsAndWebPages. Parameters are page name, and an optional pattern="(reg-exp)". The page name is:
"SomeTopic" The name of a topic located in the current web, i.e. %INCLUDE{"WebNotify"}%
"Web.Topic" A topic in another web, i.e. %INCLUDE{"TWiki.TWikiWebsTable"}%
"http://..." A full qualified URL, i.e. %INCLUDE{"http://twiki.org/"}%
%STARTINCLUDE% If present in included topic, start to include text from this location up to the end, or up to the location of the %STOPINCLUDE% variable. A normal view of the topic shows everyting exept the %STARTINCLUDE% variable itself.
%STOPINCLUDE% If present in included topic, stop to include text at this location and ignore the remaining text. A normal view of the topic shows everyting exept the %STOPINCLUDE% variable itself.
%TOC% Table of Contents of current topic.
%TOC{"SomeTopic" ...}% Table of Contents. Shows a TOC that is generated automatically based on headings of a topic. Headings in WikiSyntax ("---++ text") and HTML ("<h2>text<h2>") are taken into account. (But not "<H2>text</H2>", which can be used to exclude a heading from the TOC.) Parameters are topic name, web and depth:
Parameter: Description: Default:
"TopicName" topic name Current topic
web="Name" Name of web Current web
depth="2" Limit depth of headings shown in TOC 6
Examples: %TOC{depth="2"}%, %TOC{"TWikiDocumentation" web="TWiki"}%
%SEARCH{"text" ...}% Inline search, shows a search result embedded in a topic. Parameters are the search term, web, scope, order and many more: [1]
Parameter: Description: Default:
"text" Search term. (Is a regular expression or literal, depending on the regex parameter) required
search="text" (Alternative to above) N/A
web="Name"
web="Main Know"
web="all"
Wiki web to search: A web, a list of webs separated by whitespace, or all webs. [2] Current web
scope="topic"
scope="text"
Search topic name (title) or in the text (body) of the topic Topic text (body)
order="topic"
order="modified"
order="editby"
Sort the results of search by the topic names, last modified time, or last editor Sort by topic name
limit="all"
limit="16"
Limit the number of results returned All results
regex="on" RegularExpression search Literal search
reverse="on" Reverse the direction of the search Ascending search
casesensitive="on" Case sensitive search Ignore case
nosummary="on" Show topic title only Show topic summary
bookview="on" BookView search, e.g. show complete topic text Show topic summary
nosearch="on" Suppress search string Show search string
noheader="on" Suppress search header
Topics: Changed: By:
Show search header
nototal="on" Do not show number of topics found Show number
format="..." Flexible custom result formatting: see FormattedSearch for usage Results in table
Example: %SEARCH{"wiki" web="Main" scope="topic"}%
%METASEARCH{...}% Special search of meta data
Parameter: Description: Default:
type="topicmoved" What sort of search is required?
"topicmoved" if search for a topic that may have been moved
"parent" if searcing for topics that have a specific parent i.e. its children
required
web="%WEB%" Wiki web to search: A web, a list of webs separated by whitespace, or all webs. required
topic="%TOPIC%" The topic the search relates to required
title="Title" Text the is pre-pended to any search results required
Example: %METASEARCH{type="topicmoved" web="%WEB%" topic="%TOPIC%" title="This topic used to exist and was moved to: "}%, you may want to use this in WebTopicViewTemplate and WebTopicNonWikiTemplate
%METASEARCH{type="parent" web="%WEB%" topic="%TOPIC%" title="Children: "}%
%VAR{"NAME" web="Web"}% Get a preference value from a web other then the current one. Example: To get %WEBBGCOLOR% of the Main web write %VAR{"WEBBGCOLOR" web="Main"}%, is #444444

[1] Note: The search form uses identical names for input fields.

[2] Note: A web can be excluded from a web="all" search if you define a NOSEARCHALL=on variable in its WebPreferences.

Preferences Variables

Additional variables are defined in the preferences ( site-level ( SL ) in TWikiPreferences, web-level ( WL ) in WebPreferences of each web, and user level ( UL ) preferences in individual user topics):

Variable: Level: What:
%WIKIWEBMASTER% SL Webmaster email address (sender of email notifications) , is webmaster@netfrag.org
%WIKIWEBLIST% SL List of netfrag.org webs (in upper right corner of topics)
%WEBTOPICLIST% WL Common links of web (second line of topics)
%WEBCOPYRIGHT% SL , WL Copyright notice (bottom right corner of topics)
%WEBBGCOLOR% WL Background color of web
%NOSEARCHALL% WL Exclude web from a web="all" search (set variable to on for hidden webs)
%NEWTOPICBGCOLOR% SL , UL Background color of non existing topic. ( UL needs authentication for topic views )
%NEWTOPICFONTCOLOR% SL , UL Font color of non existing topic. ( UL needs authentication for topic views )
%EDITBOXWIDTH% SL , UL Horizontal size of edit box, is 100
%EDITBOXHEIGHT% SL , UL Vertical size of edit box, is 20
%RELEASEEDITLOCKCHECKBOX% SL , UL Default state of the "Release edit lock" (UnlockTopic) check box in preview. Checkbox is initially checked if Set RELEASEEDITLOCKCHECKBOX = checked="checked", or unchecked if empty. If checked, make sure to click on Edit to do more changes; do not go back in your browser to the edit page, or you risk that someone else will edit the topic at the same time! Value is: checked
%DONTNOTIFYCHECKBOX% SL , UL Default state of the "Minor Changes, Don't Notify" (DontNotify) check box in preview. Check box is initially checked if Set DONTNOTIFYCHECKBOX = checked="checked", or unchecked if empty. Value is: checked
%ATTACHLINKBOX% SL , UL Default state of the link check box in the attach file page. Check box is initially checked if value is set to CHECKED , unchecked if empty. If checked, a link is created to the attached file at the end of the topic. Value is:
%HTTP_EQUIV_ON_VIEW% SL http-equiv meta tags for view, rdiff, attach, search* scripts.
%HTTP_EQUIV_ON_EDIT% SL , UL http-equiv meta tags for edit script.
%HTTP_EQUIV_ON_PREVIEW% SL , UL http-equiv meta tags for preview script.
%DENYWEBCHANGE% WL List of users and groups who are not allowed to change topics in the netfrag.org web. (More in TWikiAccessControl)
%ALLOWWEBCHANGE% WL List of users and groups who are allowed to change topics in the netfrag.org web. (More in TWikiAccessControl)
%DENYTOPICCHANGE% (any topic) List of users and groups who are not allowed to change the current topic. (More in TWikiAccessControl)
%ALLOWTOPICCHANGE% (any topic) List of users and groups who are allowed to change the current topic. (More in TWikiAccessControl)
%DENYWEBRENAME% WL List of users and groups who are not allowed to rename topics in the netfrag.org web. (More in TWikiAccessControl)
%ALLOWWEBRENAME% WL List of users and groups who are allowed to rename topics in the netfrag.org web. (More in TWikiAccessControl)
%DENYTOPICRENAME% (any topic) List of users and groups who are not allowed to rename the current topic. (More in TWikiAccessControl)
%ALLOWTOPICRENAME% (any topic) List of users and groups who are allowed to rename the current topic. (More in TWikiAccessControl)
%FINALPREFERENCES% SL , WL List of preferences that are not allowed to be overridden by next level preferences

Setting Preferences

Creating Custom Variables

Example: Create a custom logo variable

-- PeterThoeny - 13 Sep 2001
-- MikeMannix - 30 Nov 2001



Note: This feature has been replaced by: TWikiForms


TWiki Plugins

Plug-in enhanced feature add-ons, with a Plugin API for developers

Overview

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

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

Preinstalled Plugins

TWiki comes with three Plugins as part of the standard installation.

Installing Plugins

Each TWikiPlugin comes with full documentation: step-by-step installation instructions, a detailed description of any special requirements, version details, and a working example for testing.

Most Plugins can be installed in three easy steps, with no programming skills required:

  1. Download the zip file containing the Plugin, documentation, and any other required files, from TWiki:Plugins.
  2. Distribute the files to their proper locations - unzip the zip archive in your TWiki installation directory - if have a standard TWiki installation, this will distribute automatically. Otherwise, place the files according to the directory paths listed on the Plugin top in TWiki:Plugins.
  3. Check the demo example on the Plugin topic: if it's working, the installation was fine!

Special Requests: Some Plugins need certain Perl modules to be preinstalled on the host system. Plugins may also use other resources, like graphics, other modules, applications, templates. In these cases, detailed instructions are in the Plugin documentation.

Each Plugin has a standard release page, located in the TWiki:Plugins web at TWiki.org. In addition to the documentation topic (SomePlugin), there's a separate development page.

On-Site Pretesting

To test new Plugins on your installation before making them public, you may want to use one of these two approaches:

Managing Plugins

When you finish installing a Plugin, you should be able to read the user instructions and go. In fact, 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.

Setting Preferences

Installed Plugins can be toggled on or off, site-wide or by web, through TWikiPreferences and individual WebPreferences:

Plugin execution order in TWiki is determined by searching Plugin topics in a specific sequence: First, full web.topicname name, if specified in INSTALLEDPLUGINS; next, the TWiki web is searched; and finally, the current web.

Plugin-specific settings are done in individual Plugin topics. Two settings are standard for each Plugin:

  1. One line description, used to form the bullets describing the Plugins in the TextFormattingRules topic:
    • Set SHORTDESCRIPTION = Blah blah woof woof.
  2. Debug Plugin, output can be seen in data/debug.txt. Set to 0=off or 1=on:
    • Set DEBUG = 0

Listing Active Plugins

Plugin status variables let you list all active Plugins wherever needed. There are two list formats:

DEMO: Automatically List Active Plugins Using Variables

Using %ACTIVATEDPLUGINS%:
On this TWiki site, the active Plugins are: DefaultPlugin, HeadlinesPlugin, InterwikiPlugin, TablePlugin, VisualConfirmPlugin.

Using %PLUGINDESCRIPTIONS%:
You can use any of these active TWiki Plugins:

The TWiki Plugin API

The Application Programming Interface (API) for TWikiPlugins provides the specifications for hooking into the core TWiki code from your external Perl Plugin module. The Plugin API is new to the Production version of TWiki with the 01-Sep-2001 release.

Available Core Functions

The lib/TWiki/Func.pm implements ALL official Plugin functions. Plugins should ONLY use functions published in this module.

ALERT! If you use functions not 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 call backs, listed in the lib/TWiki/Plugins/EmptyPlugin.pm module.

Plugin Version Detection

To eliminate the incompatibility problems bound to arise from active open Plugin development, a Plugin versioning system and an API GetVersion detection routine are provided for automatic compatibility checking.

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 Plugins by providing a programming interface for TWiki.

The DefaultPlugin Alternative

Anatomy of a Plugin

A basic TWiki Plugin consists of two elements:

The Perl module can be a block of code that connects 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.

Creating the Perl Module

Copy file lib/TWiki/Plugins/EmptyPlugin.pm to <name>Plugin.pm. EmptyPlugin.pm contains no executable code, so it does nothing, but it's ready to be used. Customize it. Refer to the Plugin API specs for more information.

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 EmptyPlugin. To copy the text, go to the page and:
    • click Edit
    • select all in the Edit box & copy
    • Cancel the edit
    • paste & save as a text file or new topic on your site
  2. Customize the template for your Plugin; you'll probably want to post a working version on your local TWiki site.
  3. Save your topic as a text file, for use in packaging and publishing your Plugin.

OUTLINE: Doc Topic Contents
Check EmptyPlugin 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.>"

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

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

Test Example: <Include an example of the Plugin in action: if it works, the installation was a success!>"

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

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

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. Publish your Plugin in three steps:

  1. Post the Plugin documentation topic in the TWiki:Plugins web:
  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.)

-- AndreaSterbini - 29 May 2001
-- PeterThoeny - 14 Sep 2001
-- MikeMannix - 03 Dec 2001