Comment Plugin

This plugin allows users to quickly post comments to a page without an edit/preview/save cycle.

( Discussion in TWiki:Plugins/CommentPluginDev )

Note: this version of the CommentPlugin will not work with TWiki versions released prior to June 2005


Inserts an edit box into the page that allows users to type in and save comments. Comments can be made

  • in different formats (as defined by a template),
  • in both forward and reverse chronological order,
  • signed or unsigned, dated or undated (as defined by a template),
  • in other topics, or other positions within the current topic.

Syntax Rules

Write the command %COMMENT{ attributes }% anywhere in a TWiki topic. %COMMENT% is also legal.

The following attributes are recognised

Name Description
type This is the name of the template to use for this comment. Comment templates are defined in a TWiki template - see Customisation, below. If this attribute is not defined, the type is whatever is defined by COMMENTPLUGIN_DEFAULT_TYPE, either in this topic or in your WebPreferences. By default this is 'below'.
target Name of the topic to add the comment to. Defaults to the current topic.
location Regular expression specifying the comment location in the target topic. Read carefully below!
mode For compatability with older versions only, synonymous with type
nonotify Set to "on" to disable change notification for target topics
noform Set to "on" to disable the automatic form that encloses your comment block - remember to insert <FORM> tags yourself!

Positioning the comment

%COMMENT supports several ways to specify where a comment should be inserted in the target topic. This is referred to as the location of the comment.

Location relative to %COMMENT tag

The default location is the %COMMENT tag itself. For example:
will add comments in the current topic, directly below the %COMMENT tag.

Location relative to a TWiki anchor

The target attribute may specify a web, and may also specify an anchor within the target topic; for example,
%COMMENT{type="above" target="%MAINWEB%.PersonalRemarks#InsertHere"}%
This uses a standard TWiki in-topic anchor as the insertion location. See TextFormattingRules for more about TWiki anchors.

Location relative to an arbitrary text string

Getting more sophisticated, you can also specify a regular expression for the target location using the location parameter. The target topic is searched for the regular expression, and the comment inserted relative to the string that the search matched. For example,
%COMMENT{type="above" location="Flights of Fancy"}%
will place comments above the first occurence of the string Flights of Fancy in the current topic.

Warning of course, if a user's comment contains the string "Flights of Fancy" they may and up changing the location for the next comment! Also, if you use a tag in the location, then you've just inserted another tag in the page that contains the %COMMENT! So be very careful how you specify the RE for location. Note that the RE is matched using perl "multiple line" mode, so ^ and $ match the start of a line and the end of a line respectively.

I look forward to someone leveraging this feature to create - for example - threaded conversations using %COMMENT.

If you specify an anchor and a location, the anchor will be ignored.

Default templates

Templates are used to define the "comment style" i.e. how comments appear in the page. The default is to add comments in "Blog like" style using bulleted lists, with the most recent comment at the top, but many other styles are available such as tables or Wiki thread mode comments. It is easy to define your own customer styles as well.

A set of default comment templates are shipped with the plugin. These are:

Template typeSorted ascending Description
above Comments, signed and dated (server time), added immediately before the target anchor, or the %COMMENT if no anchor is specified
below Comments, signed and dated (server time), added immediately below the target anchor, or the %COMMENT if no anchor is specified
bottom Comments, signed and dated (server time), added at end of the target topic (the anchor is ignored)
tableappend Comments, signed and dated (server time), formatted as an HTML table row, added above the anchor (which must be in an HTML <table>)
tableprepend Comments, signed and dated (server time), formatted as an HTML table row, added below the anchor (which must be in an HTML <table>)
threadmode Wiki thread mode comment, signed and dated (server time)
top Comments, signed and dated (server time), added at top of the topic (the anchor is ignored)

Your local installation may add more template types as well - see Customisation, below.


Customisation of the comment plugin requires

To define a comment type, you have to provide two simple template definitions in the template file; one for the prompt box, and one for the generated output. If we have a template type "mytype", these are named PROMPT:mytype and OUTPUT:mytype respectively. See comments.tmpl in the templates directory for examples.

The plugin picks up these template definitions from a standard TWiki template file, templates/comments.tmpl. This allows different templates to be defined for different TWiki skins. By default, this template includes the topic CommentsTemplate, which contains all the shipped standard templates and in turn includes TWiki.UserCommentsTemplate. This allows for several levels of customisation:

  1. To override all default templates, everywhere, change comments.tmpl to include a different topic (this customisation will be lost next time you upgrade, though).
  2. To add site-wide local template customisations, add them to TWiki.UserCommentsTemplate. You can redefine the standard templates here if you want, and your definitions will override the standard definitions.
  3. To override templates on a web-by-web basis, add a topic UserCommentsTemplate to the web (this will replace TWiki.UserCommentsTemplate)
  4. To override templates for a specific skin, add them to TWiki.UserComments<Skin>Template (where <Skin> is the name of the skin with the first letter capitalised, e.g. Pattern)

ALERT! Templates are picked up by following the standard TWiki rules for locating template files. Note that you can use %TMPL:INCLUDE to include other files of templates.

The PROMPT template

The PROMPT template defines the contents of an HTML form that is used to capture the comment. This form invokes the comment generator when submitted. Parameters to the comment generator are defined using standard HTML input fields, such as input, textarea and select. The user enters values for these parameters, and these are then available when the OUTPUT template is expanded, in the form of %URLPARAM%s.

Only the input fields of the form need be defined. The plugin automatically generates the >form< and &gt:/form< tags, unless you specify noform="on", in which case you have to provide them yourself. Note that you must define a "submit" button if you want the form to work!

If an attribute is given to the %COMMENT tag that is not one of the standard attributes, then that attribute is taken as the name of a parameter to be expanded in the PROMPT template. Expressions in the template of the form %param|default% (e.g. %rows|3%, %button|Push me%) are expanded to the values given in the %COMMENT. For example, if the PROMPT template 'example' contains:

<textarea rows=%rows|3% cols="%cols|50%" value="%tval|Rubbish%">
and the %COMMENT tag is:
%COMMENT{type="example" cols="75"}%
then the template will be expanded as
<textarea rows="3" cols="75" value="Rubbish">

As well as support for all the usual TWiki variables in templates, the following special variables are supported in the PROMPT definition:

Variable Description
%MESSAGE% A helpful generated message, either a lock message or a reminder to refresh.
%DISABLED% Set to 'disabled' when you cannot comment (e.g. in preview mode).

The OUTPUT template

The OUTPUT template defines the format for the text that actually gets embedded into the topic. All the usual TWiki variables are available in the PROMPT definition, but note that they get expanded when the comment is inserted in the text, so time, date and username will refer to the time and date when the comment was made and the user who made it.

There are also four position tags that are used to indicate where the comment should be placed, relative to the location defined in the %COMMENT tag:

%POS:TOP% If present, comments will be inserted at the top of the topic i.e. before any other text
%POS:BOTTOM% If present, comments will be inserted at the end of the topic i.e. after all existing text
%POS:BEFORE% If present, comments will be inserted immediately before the %COMMENT% tag
%POS:AFTER% If present, comments will be inserted immediately after the %COMMENT% tag
Note that these position tags are obviously mutually exclusive. If you define more than one, the result is undefined. If none is present, the default is taken from the plugin setting DEFAULT_TYPE

All the usual TWikiVariables that can be used in a topic template can also be used in an OUTPUT template. See TWikiVariables for details.


  • Description:
    • Set SHORTDESCRIPTION = Allows users to quickly post comments to a page without an edit/preview/save cycle.
  • Name of file in the 'templates' directory that contains the comment templates. The default 'comments.tmpl' automatically includes user templates from CommentsTmpl
    • Set TEMPLATES = comments
  • default template type (if not present, defaults to "below")
    • Set DEFAULT_TYPE = below

Plugin Installation Instructions

  • This plugin is pre-installed in most TWiki releases. However if you need to upgrade the plugin for any reason:
    • Download the archive file from the Plugin web (see below)
    • Unpack the archive in your twiki installation directory.
    • You may need to correct file permissions.
    • Run CommentPlugin_installer to automatically check and install other modules that this module depends on. You can also do this step manually. Dependencies: None
    • Visit configure in your TWiki installation, and enable the plugin in the {Plugins} section.

Plugin Info

Plugin Author: TWiki:Main.DavidWeller, TWiki:Main.PeterMasiar, TWiki:Main.CrawfordCurrie
Change History: Please refer to the TWiki Subversion repository for a complete change history of this plugin.
Dependencies: None
Perl Version: >= 5.6.1
Plugin Home: TWiki:Plugins/CommentPlugin
Feedback: TWiki:Plugins/CommentPluginDev

Related Topics: TWikiPreferences, TWikiPlugins

-- TWiki:Main/CrawfordCurrie - 23:00:07 01 February 2006

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Topic revision: r2 - 2005-03-27 - TWikiContributor
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