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.

Configuration

While most settings are given as part of the BREADCRUMBS tag, there are a few settings to improve rendering breadcrumbs.

Enabling Path breadcrumbs

To switch on recording the path breadcrumbs, set the BREADCRUMBSPLUGIN_RECORDTRAIL to on. Otherwise the click path of the user won't be recorded and the type setting to the BREADCRUMBS will result in an undefined behaviour.

Displaying TopicTitles

TopicTitles are a concept introduced by the TWiki:Plugins/DBCachePlugin. These are stored in a topic in the TOPICTITLE preference variable or in a formfield 'TopicTitle ' of a TWikiForm attached to the topic. If a TopicTitle is defined for a topicm, it will be displayed in the breadcrumbs instead of the normal WikiWord topic name. For efficiency it is recommended to install the TWiki:Plugins/DBCachePlugin to determine the TopicTitle.

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]]')
  • topicformat: format string for any topic items on the path; for example, parent topics. Defaults to the same as format.
  • 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
  • spaceout: space out WikiWords inserting a separator (defaults to 'off')
  • spaceoutsep: separator to be used when spacing out WikiWords
  • maxlength: maximum length of a breadcrumbs before inserting an ellipsis in the middle, 0 meaning disable this feature (defaults to 0)
  • ellipsis: character sequence to be inserted when reducing the maxlength of the breadcrumbs (defaults to ' ... ')

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)
  • $name: name of the breadcrumbs item this is the TopicTitle, spaced out or normal topic name topic
  • $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 - A flexible way to display breadcrumbs navigation

path

%BREADCRUMBS{type="path"}%

breadcrumbs to a non-existent location

%BREADCRUMBS{
  "Web1/Web2/Web3.Topic" 
  format="$name" 
  separator=" &#187; "}%
Web1 » Web2 » Web3 » Topic - A flexible way to display breadcrumbs navigation

recurse="off"

%BREADCRUMBS{
  "Web1/Web2/Web3.Topic" 
  format="$name" 
  separator=" &#187; " 
  recurse="off"}%
Web3 » Topic - A flexible way to display breadcrumbs navigation

recurse="once"

%BREADCRUMBS{"Web1/Web2/Web3.Topic" 
  format="$name" 
  separator=" &#187; " 
  recurse="once"}%
Web2 » Web3 » Topic - A flexible way to display breadcrumbs navigation

include

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

exclude

%BREADCRUMBS{"Web1/Web2/Web3.Topic" 
  format="$name" 
  separator=" &#187; " 
  exclude="Web2"}%
Web1 » Web2 » Web3 » Topic - A flexible way to display breadcrumbs navigation

Plugin Installation Instructions

%$INSTALL_INSTRUCTIONS%

Plugin Info

Plugin Author: TWiki:Main.MichaelDaum
Copyright ©: 2006-2008, Michael Daum http://michaeldaumconsulting.com
License: GPL (GNU General Public License)
Plugin Version: v2.00 (%$VERSION%)
Change History:  
28 Apr 2008: many new features for 2.0: topic titles, ellipsis, ...
08 May 2007: respect HOMETOPIC setting, don't hardcoded 'WebHome'
19 Apr 2007: TWiki:Main.CrawfordCurrie added topicformat
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 - 28 Apr 2008

TWiki.BreadCrumbsPlugin - Topic revision: r2 - 2008-04-28 - 16:53:17 - micha
 
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