Comment Plugin

RELEASE 12 Sep 2009

Comment Plugin lets users quickly post comments to a page without an edit/preview/save cycle.

Related topics: CommentPluginTemplates, CommentPluginExamples


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.


Write %COMMENT{attributes}% anywhere in a topic.

  • A %COMMENT% without parameters shows a simple text box.
  • The following standard attributes are recognized
    Name Description Default
    type This is the name of the template to use for this comment. Comment templates are defined in a Foswiki 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. below
    default Default text to put into the textarea of the prompt.  
    target Name of the topic to add the comment to the current topic
    location Regular expression specifying the comment location in the target topic. Read carefully the CommentPlugin documentation!  
    mode For compatibility with older versions only, synonymous with type  
    nonotify Set to "on" to disable change notification for target topics off
    noform Set to "on" to disable the automatic form that encloses your comment block - remember to insert <form> tags yourself! See CommentPluginExamples#noform for an example. off
    nopost Set to "on" to disable insertion of the posted text into the topic. off
    remove Set to "on" to remove the comment prompt after the first time it is clicked. off
    button Button label text Add comment

(See also additional attributes)

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 an 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 in-topic anchor as the insertion location. See TextFormattingRules for more about Foswiki 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.
Also note that you cannot have the text location=" just before the location.

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 - see also CommentPluginTemplates:

Template type Description
top Comments, signed and dated (server time), added at top of the topic (the anchor is ignored)
bottom Comments, signed and dated (server time), added at end of the target topic (the anchor is ignored)
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
belowthreadmode Comments, signed and dated, added recurse after comment box
threadmode Wiki thread mode comment, signed and dated (server time)
tableprepend Comments, signed and dated (server time), formatted as an HTML table row, added below the anchor (which must be in an HTML <table>)
tableappend Comments, signed and dated (server time), formatted as an HTML table row, added above the anchor (which must be in an HTML <table>)
action Action added to action table directly above comment box (see Plugin Installation Instructions below for important notes)
table Tablerows adding on end
toctalk Talk using TOC adding on end
bookmark Create a list of annotated bookmarks
return Post to a different topic and return

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


Customisation of the comment plugin requires
  • familiarity with HTML forms
  • some familiarity with the Skin Templates.

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 template file, templates/comments.tmpl. This allows different templates to be defined for different Foswiki skins.

Defining custom templates

By default, templates/comments.tmpl includes the topic CommentPluginTemplate, which contains all the shipped standard templates and in turn includes System.UserCommentsTemplate that can include non-standard customisations.

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 UserCommentsTemplate? (create if it does not exist yet). 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 System.UserCommentsTemplate)
  4. To override templates for a specific skin, add them to System.UserComments<Skin>Template (where <Skin> is the name of the skin with the first letter capitalised, e.g. Pattern)

You can also define a comment template in a topic, by passing the topic location with templatetopic. For example:

%COMMENT{type="blogpost" templatetopic="BlogPostCommentTemplate" target="%TOPIC%" button="Add comment" }%

templatetopic accepts topic or web.topic syntax. See an example in CommentPluginExamples:templatetopic.

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

Customisation example

Provide both a PROMPT and an OUTPUT definition:


Call your custom comment with:


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 </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!

Providing attribute values

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">

Special macros

As well as support for all the usual macros in templates, the following special macros are supported in the PROMPT definition:
Macro Description
%DISABLED% Set to 'disabled' when you cannot comment (e.g. in preview mode).
%MESSAGE% The text specified by default. This may be overridden by a helpful message when the prompt is DISABLED.

EXPERT Note that when a comment is saved, the save script is invoked on the target topic, with a number of parameters provided by the comment form. Normally the CommentPlugin will provide these fields in the form, but experts can also provide the fields themselves in order to get finer control over what is submitted, or you might want to define your own HTML forms that do comment submission. The parameters that the CommentPlugin recognises are as follows:

CGI parameter Description
comment_action Must be save to get the CommentPlugin to perform
comment_type Type of the OUTPUT template
comment_index Zero-based index of the %COMMENT in the source topic. Used to place a post relative to an existing %COMMENT.
comment_anchor Anchor taken from the target spec
comment_location As passed to %COMMENT
comment_nonotify As passed to %COMMENT
comment_remove Zero-based index of a %COMMENT to remove from the target topic
comment_nopost As passed to %COMMENT
comment_templatetopic As passed to %COMMENT
Note that comment_location overrides comment_anchor, and both override comment_index. Example, shows an "I Approve" button that adds your approval signature to the end of the topic:
<form method="post" action="%SCRIPTURL{save}%/%WEB%/%TOPIC%">
<input type="submit" value="I Approve" />
<input type="hidden" name="comment_action" value="save" />
<input type="hidden" name="comment_type" value="bottom" />
<input type="hidden" name="comment" value="I Approve" />

Customisation example with custom form template

Write a custom form in a topic.
  • In the form set the location of the prompt with %COMMENTPROMPT%; the prompt will be positioned here.
  • In %COMMENT use parameter noform="on"
  • In %COMMENT use parameter templatetopic to point to the topic with the form template

Example form:

<form method="post" action="%SCRIPTURL{save}%/%BASEWEB%/%BASETOPIC%" enctype="application/x-www-form-urlencoded" name="examplecomment" id="examplecomment">
<input type="hidden" name="redirectto" value="%BASEWEB%.%BASETOPIC%" />

Example comment:

%COMMENT{noform="on" type="example" templatetopic="Sandbox.CommentPluginTemplateExample" target="%TOPIC%" button="Add comment" }%

The OUTPUT template

The OUTPUT template defines the format for the text that actually gets embedded into the topic. All the usual macros 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

%COMMENTPROMPT% Use with a custom form. If present, the comment prompt will be positioned here.

All the usual macros that can be used in a topic template can also be used in an OUTPUT template.


Two preference settings are recognised by the CommentPlugin:
Preference Default Description
%COMMENTPLUGIN_TEMPLATES% comments Name of template file in the 'templates' directory that contains the comment templates. The default 'comments.tmpl' automatically includes user templates from CommentPluginTemplate, which in turn includes UserCommentsTemplate?.
%COMMENTPLUGIN_DEFAULT_TYPE% above Default template type
These can be set in %USERSWEB%.SitePreferences, in WebPreferences, or in individual topics.


Plugin Installation Instructions

  • This plugin is pre-installed in most releases. However if you need to upgrade the plugin for any reason:
  • Download the archive file from the Extensions web (see below)
  • Unpack the archive in your Foswiki installation directory.
    • You may need to correct file permissions
  • Run CommentPlugin_installer to automatically check and install other modules that this module depends on, and enable the plugin.
  • Alternatively,
    • Manually resolve the dependencies listed below. None
  • Use configure to enable the plugin

Note that if you want to use the action template then you must also:

  1. Install the Foswiki:Extensions/ActionTrackerPlugin;
  2. Put the CommentPlugin before the ActionTrackerPlugin in the {PluginsOrder} configuration option (in configure)

Plugin Info

Another great extension from the WikiRing - working together to improve your wiki experience!

Plugin Author: Foswiki:Main.CrawfordCurrie inspired by the work of TWiki:Main.DavidWeller and TWiki:Main.PeterMasiar
Copyright: © 2004, Foswiki:Main.CrawfordCurrie
© 2004-2009 Foswiki:System.ProjectContributor
License: GPL (GNU General Public License)
Release: 12 Sep 2009
Version: 4843 (2009-09-11)
Change History:  
12 Sep 2009 Foswikitask:Item8269 - Targeting anchors broken by Item727 is fixed.
04 Jun 2009 Foswikitask:Item1668 - The action template used with ActionTrackerPlugin now uses new syntax ending with %ENDACTION. This makes each action item appear on a new line. Additionally new lines are now correctly saved as html br tags and not as html encoded br tag
Foswikitask:Item1640 - Templates shipped with the plugin no longer encodes the user date entered when the date is saved so that it is possible for the user to use macros.
15 Jan 2008 Foswikitask:Item727 - data loss issue when missing anchor or location
13 Jan 2009 Foswikitask:Item736 - Make CommentPlugin aware of CompareRevisionsAddOn? bin script.
16 Dec 2008 Foswiki version
03 Aug 2008 The TWiki 4.2.1 release version
11 Apr 2008 TWikibug:Item5518 corrected the template definition for bulletabove
05 Sep 2007 TWikibug:Item3689 corrected location handling TWikibug:Item4181 added VarCOMMENT TWikibug:Item4402 corrected access check
22 Jun 2007 Removed the long-deprecated %TIME (use %GMTIME instead). Minor doc changes
14021 TWikibug:Item3755 Fixed incorrect handling of line terminators when targeting an anchor
13311 Added option to define a comment template in any topic. Pass the topic location with templatetopic (either topic or web.topic). See an example in CommentPluginExamples:templatetopic.
12822 TWikibug:Item3598 minor doc fixes
12750 TWikibug:Item3510 added a note about the changed template spec in TWiki 4.1.0. Code remains unchanged
11358 TWikibug:Item2802 moved SHORTDESCRIPTION to .pm. Coded up TWiki:main.PankajPant's suggestions as nopost and remove. Added default text for the %COMMENT as requested by TWiki:Main.AndyGlew
11118 TWikibug:Item2322 removed span tag around oneliner bullet output
8788 TWikibug:Item1465 Item1577: reverted 8433 to fix inclusion of correct user templates
8787 TWikibug:Item1573 renamed standard templates topic to avoid naming clash on Windows, where filenames are case-insensitive
8433 TWikibug:Item1465 Fix 'TWiki.' to 'System.'; also fixed include 'UserComments' to 'UserCommentsTemplate' (at least that is what the doc suggests)
7427 TWikibug:Item845 removed duplicate date in default comments; stick with server time
7251 TWikibug:Item810 fix for user template inclusion; reorganised templates to make customisation easier
5906 TWikibug:Item143 apache warning from comment plugin when CommentsTmpl.txt not found
5519 CommentPluginOnAnchorsBroken: incorporated JacobEisinger's fix
5518 CommentPluginOnAnchorsBroken: incorporated OlivierBerger's fix
5455 On Niels Kodslo's prompting, removed the global recursion prevention that I believe is no longer needed.
5280 Removed templates, and some minor fixes
5250 Removed newlines from prompt box
4902 Changed to use viewauth. Moved templates into user topics.
4901 Added templates in user webs support
4897 Fixes for disabling during preview; re-enabled old legacy parameters
4889 Chopped down from PeterMasiar version, removing several parameters, savecomment script, changing way templates are done. Major rewrite, atcherly.
4882 Update from PeterMasiar's 2.0 version, plus documentation and small code improvements.
4745 06 Mar 2002 initial commit
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