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BreadCrumbsPlugin

Description

This plugin helps you to locate where you are, and shows you how you can escape from there using breadcrumbs navigation.

Two types of breadcrumb are supported; "location" breadcrumbs, which show you where you are in the site hierarchy, taking into account topic parent relationships, and "path" breadcrumbs, that simply show you where you have been, but without going in circles.

In a way, location breadcrumbs have always been supported by TWiki using the META{"parent"} variable to display the list of parent topics. Since version 4.x TWiki also supports hierarchical subwebs, but the breadcrumbs support of TWiki does not allow the display of parent webs as part of of the location breadcrumbs.

Path breadcrumbs show you which topics you visited to reach the current topic. If you revisit a topic you visited earlier, the path is trimmed back to that topic, so it gives you a sort of visual history of where you have been on the site. Path breadcrumbs require that you have session support enabled.

The plugin also gives a great deal of flexibility in deciding which parts of the breadcrumbs should be rendered, and how each individual breadcrumb is displayed.

Syntax

%BREADCRUMBS%, %BREADCRUMBS{"<web>.<topic>" ...}%

Parameters:

  • <web>.<topic>: the location to which breadcrumbs should be generated (type="location" only, ignored if type="path") defaults to the current topic
  • type: "location" (the default) or "path"
  • header: format string prepended to the output result
  • format: format string to render one item on the breadcrumbs path (defaults to '[[$webtopic][$name]]')
  • footer: format string appended to the output result
  • separator: format string to be put between items (defaults to one space char)
  • include: regular expression that items must match to be part of the path
  • exclude: regular expression that items must not match to be part of the path
  • recurse: (type="location" only)can be one or more of the following values (comma separated) to decide which parts of the breadcrumbs path should be included (defaults to 'on'):
    • on: include all parent webs and all parent topics
    • off: include only the current web and the current topic
    • weboff: don't recurse on webs, include only the current web
    • topicoff: don't recurse on topics, include only the current topic
    • webonce: include the next parent web but not the parent web's parent web
    • topiconce: include the next parent topic but not the parent topic's parent topic
    • once: short formf of webonce, topiconce

Pseudo-variables:
Each of the above format strings (format, header, footer, separator) may contain special variables:

  • $name: the name of the breadcrumb, this is the topic name or the web name having its parent web part being stripped off (that is Bar instead of Sandbox/Foo/Bar)
  • $webtopic: the full web.topic of the breadcrumb (twiki syntax)
  • $target: the full web/topic of the breadcrumb (url syntax)
  • $n: replaced with a newline char (\n)
  • $percnt: replaced with a percent char (%)
  • $dollar: replaced with a dollar char ($)
  • $nop: removed from the format string before expanding common TWiki variables

Examples

default

%BREADCRUMBS%
TWiki BreadCrumbsPlugin

path

%BREADCRUMBS{type="path"}%
BreadCrumbsPlugin

breadcrumbs to a non-existent location

%BREADCRUMBS{
  "Web1/Web2/Web3.Topic" 
  format="$name" 
  separator=" &#187; "}%
Web1 » Web2 » Web3 » Topic

recurse="off"

%BREADCRUMBS{
  "Web1/Web2/Web3.Topic" 
  format="$name" 
  separator=" &#187; " 
  recurse="off"}%
Web3 » Topic

recurse="once"

%BREADCRUMBS{"Web1/Web2/Web3.Topic" 
  format="$name" 
  separator=" &#187; " 
  recurse="once"}%
Web2 » Web3 » Topic

include

%BREADCRUMBS{"Web1/Web2/Web3.Topic" 
  format="$name" 
  separator=" &#187; " 
  include="Web(1|3).*"}%
Web1 » Web3

exclude

%BREADCRUMBS{"Web1/Web2/Web3.Topic" 
  format="$name" 
  separator=" &#187; " 
  exclude="Web2"}%
Web1 » Web3 » Topic

Plugin Installation Instructions

You do not need to install anything in the browser to use this extension. The following instructions are for the administrator who installs the extension on the server where TWiki is running.

Like many other TWiki extensions, this module is shipped with a fully automatic installer script written using the BuildContrib.

  • If you have TWiki 4.1 or later, and Perl 5.8, you can install from the configure interface (Go to Plugins->Find More Extensions)
    • The webserver user has to have permission to write to all areas of your installation for this to work.
  • If you have a permanent connection to the internet (and Perl 5.8), you are recommended to use the automatic installer script
    • Just download the BreadCrumbsPlugin_installer perl script and run it.
  • Notes:
    • The installer script will:
      • Automatically resolve dependencies,
      • Copy files into the right places in your local install (even if you have renamed data directories),
      • check in new versions of any installed files that have existing RCS histories files in your existing install (such as topics).
      • If the $TWIKI_PACKAGES environment variable is set to point to a directory, the installer will try to get archives from there. Otherwise it will try to download from twiki.org or cpan.org, as appropriate.
      • (Developers only: the script will look for twikiplugins/BreadCrumbsPlugin/BreadCrumbsPlugin.tgz before downloading from TWiki.org)
    • If you don't have a permanent connection, you can still use the automatic installer, by downloading all required TWiki archives to a local directory.
      • Point the environment variable $TWIKI_PACKAGES to this directory, and the installer script will look there first for required TWiki packages.
        • $TWIKI_PACKAGES is actually a path; you can list several directories separated by :
      • If you are behind a firewall that blocks access to CPAN, you can build a local CPAN mini-mirror, as described at http://twiki.org/cgi-bin/view/Codev/BuildingDakar#CPAN_local_minimirror
  • If you don't want to use the installer script, or have problems on your platform (e.g. you don't have Perl 5.8), then you can still install manually:
    1. Download and unpack one of the .zip or .tgz archives to a temporary directory.
    2. Manually copy the contents across to the relevant places in your TWiki installation.
    3. Check in any installed files that have existing ,v files in your existing install (take care not to lock the files when you check in)
    4. Manually edit LocalSite.cfg to set any configuration variables.
    5. Run configure and enable the module, if it is a plugin.
    6. Repeat from step 1 for any missing dependencies.

Plugin Info

Plugin Author: TWiki:Main.MichaelDaum
Copyright ©: 2006, MichaelDaum@WikiRing.com
License: GPL (GNU General Public License)
Plugin Version: v0.12 (%$VERSION)
Change History:  
20 Feb 2007: TWiki:Main.CrawfordCurrie added path breadcrumbs
18 Dec 2006: added $webtopic pseudo-parameter
31 Aug 2006: added NO_PREFS_IN_TOPIC; removed commonTagsHandler thus dropping cairo support
08 Aug 2006: fixed topic parents not showing up; don't show non-existing topics
29 Jul 2006: fixed infinit loop when a topic is its own parent topic
28 Jul 2006: initial version; don't add the topic parent 'WebHome' to the path
CPAN Dependencies: none
Other Dependencies: none
Perl Version: 5.8
TWiki:Plugins/Benchmark: GoodStyle nn%, FormattedSearch nn%, BreadCrumbsPlugin nn%
Plugin Home: TWiki:Plugins/BreadCrumbsPlugin
Feedback: TWiki:Plugins/BreadCrumbsPluginDev
Appraisal: TWiki:Plugins/BreadCrumbsPluginAppraisal

-- TWiki:Main/MichaelDaum - 20 Feb 2006

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