Comment Plugin

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

Features

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 recognized (see also additional attributes):

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'.
default	Default text to put into the textarea of the prompt.
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! See CommentPluginExamples#noform for an example.
nopost	Set to "on" to disable insertion of the posted text into the topic.
remove	Set to "on" to remove the comment prompt after the first time it is clicked.
button	Button label text; by default Add comment.

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:

%COMMENT{type="below"}%

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 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
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>)

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

Customisation

Customisation of the comment plugin requires

• familiarity with HTML forms
• some familiarity with the TWiki templating language.

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.

Defining custom templates

By default, templates/comments.tmpl includes the topic CommentPluginTemplate, which contains all the shipped standard templates and in turn includes TWiki.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 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)

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.

Customisation example

Provide both a PROMPT and an OUTPUT definition:

%TMPL:DEF{PROMPT:myComment}%%TMPL:P{promptbox}%%TMPL:END%
%TMPL:DEF{OUTPUT:myComment}%%TMPL:P{outputoneliner}%%POS:TOP%
%TMPL:END%

Call your custom comment with:

%COMMENT{type="myComment"}%

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 variables

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

Variable	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 TWiki 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

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" />
</form>

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.

Settings

Two TWiki Preference variables 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 TWikiPreferences, in WebPreferences or in individual topics.

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, and enable the plugin.
• Alternatively,
  • Manually resolve the dependencies listed below. None
• Use configure to enable the plugin

Plugin Info

Plugin Author:	TWiki:Main.DavidWeller, TWiki:Main.PeterMasiar, TWiki:Main.CrawfordCurrie http://www.c-dot.co.uk
Change History:
11358	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	Item2322 removed span tag around oneliner bullet output
8788	Item1465 Item1577: reverted 8433 to fix inclusion of correct user templates
8787	Item1573 renamed standard templates topic to avoid naming clash on Windows, where filenames are case-insensitive
8433	Item1465 Fix 'TWiki.' to 'TWiki.'; also fixed include 'UserComments' to 'UserCommentsTemplate' (at least that is what the doc suggests)
7427	Item845 removed duplicate date in default comments; stick with server time
7251	Item810 fix for user template inclusion; reorganised templates to make customisation easier
5906	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
Perl Version:	>= 5.6.1
Plugin Home:	TWiki:Plugins/CommentPlugin
Feedback:	TWiki:Plugins/CommentPluginDev

Related Topics: TWikiPreferences, TWikiPlugins

-- TWiki:Main/CrawfordCurrie - 05:07:17 16 January 2007