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[openafs-wiki.git] / TWiki / CommentPlugin.mdwn

# <a name="Comment Plugin"></a><a name=" Comment Plugin"></a> Comment Plugin

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

<div style="background-color: #ffc">WARNING: TWiki-4 only. If you want to use this plugin with an earlier version of TWiki, please use <a href="http://twiki.org/cgi-bin/attach/Plugins/CommentPlugin?filename=CommentPlugin.zip&revInfo=1" target="_top">revision 31 of the zip</a>.</div>

<div>
  <ul>
    <li><a href="#Features"> Features</a></li>
    <li><a href="#Syntax Rules"> Syntax Rules</a><ul>
        <li><a href="#Positioning the comment"> Positioning the comment</a><ul>
            <li><a href="#Location relative to %COMMENT ta"> Location relative to <code>%COMMENT</code> tag</a></li>
            <li><a href="#Location relative to a TWiki anc"> Location relative to a TWiki anchor</a></li>
            <li><a href="#Location relative to an arbitrar"> Location relative to an arbitrary text string</a></li>
          </ul>
        </li>
        <li><a href="#Default templates"> Default templates</a></li>
      </ul>
    </li>
    <li><a href="#Customisation"> Customisation</a><ul>
        <li><a href="#Defining custom templates"> Defining custom templates</a></li>
        <li><a href="#Customisation example"> Customisation example</a></li>
        <li><a href="#The <code>PROMPT</code> template"> The PROMPT template</a><ul>
            <li><a href="#Providing attribute values"> Providing attribute values</a></li>
            <li><a href="#Special variables"> Special variables</a></li>
          </ul>
        </li>
        <li><a href="#The <code>OUTPUT</code> template"> The OUTPUT template</a></li>
      </ul>
    </li>
    <li><a href="#Settings"> Settings</a></li>
    <li><a href="#Plugin Installation Instructions"> Plugin Installation Instructions</a></li>
    <li><a href="#Plugin Info"> Plugin Info</a></li>
  </ul>
</div>

## <a name="Features"></a> 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.

## <a name="Syntax Rules"></a> Syntax Rules

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

<a name="StandardAttrs"></a> The following attributes are recognized (see also [[additional attributes|Main/WebHome#MoreAttrs]]):

<table border="1" cellpadding="0" cellspacing="0">
  <tr>
    <th bgcolor="#99CCCC"><strong> Name </strong></th>
    <th bgcolor="#99CCCC"><strong> Description </strong></th>
  </tr>
  <tr>
    <td><code>type</code></td>
    <td> This is the name of the template to use for this comment. Comment templates are defined in a TWiki template - see [[Main/WebHome#TemPlates]], below. If this attribute is not defined, the type is whatever is defined by COMMENTPLUGIN_DEFAULT_TYPE, either in this topic or in your [[Main/WebPreferences]]. By default this is 'below'. </td>
  </tr>
  <tr>
    <td><code>default</code></td>
    <td> Default text to put into the textarea of the prompt. </td>
  </tr>
  <tr>
    <td><code>target</code></td>
    <td> Name of the topic to add the comment to. Defaults to the current topic. </td>
  </tr>
  <tr>
    <td><code>location</code></td>
    <td> Regular expression specifying the comment location in the target topic. Read <em>carefully</em> below! </td>
  </tr>
  <tr>
    <td><code>mode</code></td>
    <td> For compatability with older versions only, synonymous with <code>type</code></td>
  </tr>
  <tr>
    <td><code>nonotify</code></td>
    <td> Set to "on" to disable change notification for target topics </td>
  </tr>
  <tr>
    <td><code>noform</code></td>
    <td> Set to "on" to disable the automatic form that encloses your comment block - <em>remember</em> to insert <code>&lt;form&gt;</code> tags yourself! See [[Main/CommentPluginExamples#noform]] for an example. </td>
  </tr>
  <tr>
    <td><code>nopost</code></td>
    <td> Set to "on" to disable insertion of the posted text into the topic. </td>
  </tr>
  <tr>
    <td><code>remove</code></td>
    <td> Set to "on" to remove the comment prompt after the first time it is clicked. </td>
  </tr>
  <tr>
    <td><code>button</code></td>
    <td> Button label text; by default <code>Add comment</code>. </td>
  </tr>
</table>

### <a name="Positioning the comment"></a> 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.

#### <a name="Location relative to %COMMENT ta"></a> 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.

#### <a name="Location relative to a TWiki anc"></a> 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.

#### <a name="Location relative to an arbitrar"></a> 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.

### <a name="Default templates"></a> 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:

<table border="1" cellpadding="0" cellspacing="0">
  <tr>
    <th bgcolor="#99CCCC"><strong> Template type </strong></th>
    <th bgcolor="#99CCCC"><strong> Description </strong></th>
  </tr>
  <tr>
    <td><code>top</code></td>
    <td> Comments, signed and dated (server time), added at top of the topic (the anchor is ignored) </td>
  </tr>
  <tr>
    <td><code>bottom</code></td>
    <td> Comments, signed and dated (server time), added at end of the target topic (the anchor is ignored) </td>
  </tr>
  <tr>
    <td><code>above</code></td>
    <td> Comments, signed and dated (server time), added immediately before the target anchor, or the <code>%COMMENT</code> if no anchor is specified </td>
  </tr>
  <tr>
    <td><code>below</code></td>
    <td> Comments, signed and dated (server time), added immediately below the target anchor, or the <code>%COMMENT</code> if no anchor is specified </td>
  </tr>
  <tr>
    <td><code>threadmode</code></td>
    <td> Wiki thread mode comment, signed and dated (server time) </td>
  </tr>
  <tr>
    <td><code>tableprepend</code></td>
    <td> Comments, signed and dated (server time), formatted as an HTML table row, added below the anchor (which must be in an HTML &lt;table&gt;) </td>
  </tr>
  <tr>
    <td><code>tableappend</code></td>
    <td> Comments, signed and dated (server time), formatted as an HTML table row, added above the anchor (which must be in an HTML &lt;table&gt;) </td>
  </tr>
</table>

Your local installation may add more template types as well - see [[Customisation|Main/WebHome#TemPlates]], below.

<a name="TemPlates"></a>

## <a name="Customisation"></a> Customisation

Customisation of the comment plugin requires

- familiarity with HTML forms
- some familiarity with the [[TWiki templating language|TWiki/TWikiTemplates]].

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.

### <a name="Defining custom templates"></a> 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&lt;Skin&gt;Template (where &lt;Skin&gt; is the name of the skin with the first letter capitalised, e.g. Pattern)

%X% Templates are picked up by following the [[standard TWiki rules|Main/TWikiTemplates#Finding_Templates]] for locating template files. Note that you can use `%TMPL:INCLUDE` to include other files of templates.

%X% Note that from TWiki release 4.1.0 leading and trailing whitespace is no longer stripped. This means that when you upgrade to TWiki 4.1.X you may need to remove the first line break in your custom comment templates. See [[TWikiReleaseNotes04x01]] for more information.

### <a name="Customisation example"></a> 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"}%

### <a name="The &lt;code&gt;PROMPT&lt;/code&gt; template"></a> 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!

<a name="MoreAttrs"></a>

#### <a name="Providing attribute values"></a> Providing attribute values

If an attribute is given to the `%COMMENT` tag that is not one of the [[standard attributes|Main/WebHome#StandardAttrs]], 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">

#### <a name="Special variables"></a> Special variables

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

<table border="1" cellpadding="0" cellspacing="0">
  <tr>
    <th bgcolor="#99CCCC"><strong> Variable </strong></th>
    <th bgcolor="#99CCCC"><strong> Description </strong></th>
  </tr>
  <tr>
    <td><code>%DISABLED%</code></td>
    <td> Set to 'disabled' when you cannot comment (e.g. in preview mode). </td>
  </tr>
  <tr>
    <td><code>%MESSAGE%</code></td>
    <td> The text specified by <code>default</code>. This may be overridden by a helpful message when the prompt is DISABLED. </td>
  </tr>
</table>

**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:

<table border="1" cellpadding="0" cellspacing="0">
  <tr>
    <th bgcolor="#99CCCC"><strong> CGI parameter </strong></th>
    <th bgcolor="#99CCCC"><strong> Description </strong></th>
  </tr>
  <tr>
    <td><code>comment_action</code></td>
    <td> Must be <code>save</code> to get the [[Main/CommentPlugin]] to perform </td>
  </tr>
  <tr>
    <td><code>comment_type</code></td>
    <td> Type of the OUTPUT template </td>
  </tr>
  <tr>
    <td><code>comment_index</code></td>
    <td> Zero-based index of the %COMMENT in the source topic. Used to place a post relative to an existing %COMMENT. </td>
  </tr>
  <tr>
    <td><code>comment_anchor</code></td>
    <td> Anchor taken from the <code>target</code> spec </td>
  </tr>
  <tr>
    <td><code>comment_location</code></td>
    <td> As passed to %COMMENT </td>
  </tr>
  <tr>
    <td><code>comment_nonotify</code></td>
    <td> As passed to %COMMENT </td>
  </tr>
  <tr>
    <td><code>comment_remove</code></td>
    <td> Zero-based index of a %COMMENT to remove from the target topic </td>
  </tr>
  <tr>
    <td><code>comment_nopost</code></td>
    <td> As passed to %COMMENT </td>
  </tr>
</table>

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>

### <a name="The &lt;code&gt;OUTPUT&lt;/code&gt; template"></a> 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:

<table border="1" cellpadding="0" cellspacing="0">
  <tr>
    <td><code>%POS:TOP%</code></td>
    <td> If present, comments will be inserted <strong>at the top of the topic</strong> i.e. before any other text </td>
  </tr>
  <tr>
    <td><code>%POS:BOTTOM%</code></td>
    <td> If present, comments will be inserted <strong>at the end of the topic</strong> i.e. after all existing text </td>
  </tr>
  <tr>
    <td><code>%POS:BEFORE%</code></td>
    <td> If present, comments will be inserted <b>immediately before the <code>%COMMENT%</code> tag</b></td>
  </tr>
  <tr>
    <td><code>%POS:AFTER%</code></td>
    <td> If present, comments will be inserted <b>immediately after the <code>%COMMENT%</code> tag</b></td>
  </tr>
</table>

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.

## <a name="Settings"></a> Settings

Two TWiki Preference variables are recognised by the [[CommentPlugin]]:

<table border="1" cellpadding="0" cellspacing="0">
  <tr>
    <th bgcolor="#99CCCC"><strong> Preference </strong></th>
    <th bgcolor="#99CCCC"><strong> Default </strong></th>
    <th bgcolor="#99CCCC"><strong> Description </strong></th>
  </tr>
  <tr>
    <td><code>%COMMENTPLUGIN_TEMPLATES%</code></td>
    <td><code>comments</code></td>
    <td> Name of template file in the 'templates' directory that contains the comment templates. The default 'comments.tmpl' automatically includes user templates from [[TWiki/CommentPluginTemplate]], which in turn includes [[TWiki/UserCommentsTemplate]]. </td>
  </tr>
  <tr>
    <td><code>%COMMENTPLUGIN_DEFAULT_TYPE%</code></td>
    <td><code>above</code></td>
    <td> Default template type </td>
  </tr>
</table>

These can be set in TWikiPreferences, in WebPreferences or in individual topics.

## <a name="Plugin Installation Instructions"></a> 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 <code>**%TOPIC%\_installer**</code> 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

## <a name="Plugin Info"></a> Plugin Info

<table border="1" cellpadding="0" cellspacing="0">
  <tr>
    <td align="right"> Plugin Author: </td>
    <td> TWiki:Main.DavidWeller, TWiki:Main.PeterMasiar, TWiki:Main.CrawfordCurrie <a href="http://www.c-dot.co.uk" target="_top">http://www.c-dot.co.uk</a></td>
  </tr>
  <tr>
    <td align="right"> Copyright: </td>
    <td> © 2004, TWiki:Main.CrawfordCurrie<br />© 2004-2007 TWiki:TWiki.TWikiContributor </td>
  </tr>
  <tr>
    <td align="right"> License: </td>
    <td> GPL (<a href="http://www.gnu.org/copyleft/gpl.html" target="_top">GNU General Public License</a>) </td>
  </tr>
  <tr>
    <td align="right"> Plugin Version: </td>
    <td> 12750 (04 Feb 2007) </td>
  </tr>
  <tr>
    <td align="right"> Change History: </td>
    <td>  </td>
  </tr>
  <tr>
    <td align="right"> 12750 </td>
    <td><a href="http://develop.twiki.org/~twiki4/cgi-bin/view/Bugs/Item3510" rel="nofollow">Item3510</a> added a note about the changed template spec in TWiki 4.1.0. Code remains unchanged </td>
  </tr>
  <tr>
    <td align="right"> 11358 </td>
    <td><a href="http://develop.twiki.org/~twiki4/cgi-bin/view/Bugs/Item2802" rel="nofollow">Item2802</a> moved SHORTDESCRIPTION to .pm. Coded up TWiki:main.PankajPant's suggestions as <code>nopost</code> and <code>remove</code>. Added default text for the %COMMENT as requested by TWiki:Main.AndyGlew </td>
  </tr>
  <tr>
    <td align="right"> 11118 </td>
    <td><a href="http://develop.twiki.org/~twiki4/cgi-bin/view/Bugs/Item2322" rel="nofollow">Item2322</a> removed span tag around oneliner bullet output </td>
  </tr>
  <tr>
    <td align="right"> 8788 </td>
    <td><a href="http://develop.twiki.org/~twiki4/cgi-bin/view/Bugs/Item1465" rel="nofollow">Item1465</a> Item1577: reverted 8433 to fix inclusion of correct user templates </td>
  </tr>
  <tr>
    <td align="right"> 8787 </td>
    <td><a href="http://develop.twiki.org/~twiki4/cgi-bin/view/Bugs/Item1573" rel="nofollow">Item1573</a> renamed standard templates topic to avoid naming clash on Windows, where filenames are case-insensitive </td>
  </tr>
  <tr>
    <td align="right"> 8433 </td>
    <td><a href="http://develop.twiki.org/~twiki4/cgi-bin/view/Bugs/Item1465" rel="nofollow">Item1465</a> Fix 'TWiki.' to 'TWiki.'; also fixed include 'UserComments' to 'UserCommentsTemplate' (at least that is what the doc suggests) </td>
  </tr>
  <tr>
    <td align="right"> 7427 </td>
    <td><a href="http://develop.twiki.org/~twiki4/cgi-bin/view/Bugs/Item845" rel="nofollow">Item845</a> removed duplicate date in default comments; stick with server time </td>
  </tr>
  <tr>
    <td align="right"> 7251 </td>
    <td><a href="http://develop.twiki.org/~twiki4/cgi-bin/view/Bugs/Item810" rel="nofollow">Item810</a> fix for user template inclusion; reorganised templates to make customisation easier </td>
  </tr>
  <tr>
    <td align="right"> 5906 </td>
    <td><a href="http://develop.twiki.org/~twiki4/cgi-bin/view/Bugs/Item143" rel="nofollow">Item143</a> apache warning from comment plugin when CommentsTmpl.txt not found </td>
  </tr>
  <tr>
    <td align="right"> 5519 </td>
    <td> CommentPluginOnAnchorsBroken: incorporated JacobEisinger's fix </td>
  </tr>
  <tr>
    <td align="right"> 5518 </td>
    <td> CommentPluginOnAnchorsBroken: incorporated OlivierBerger's fix </td>
  </tr>
  <tr>
    <td align="right"> 5455 </td>
    <td> On Niels Kodslo's prompting, removed the global recursion prevention that I believe is no longer needed. </td>
  </tr>
  <tr>
    <td align="right"> 5280 </td>
    <td> Removed templates, and some minor fixes </td>
  </tr>
  <tr>
    <td align="right"> 5250 </td>
    <td> Removed newlines from prompt box </td>
  </tr>
  <tr>
    <td align="right"> 4902 </td>
    <td> Changed to use viewauth. Moved templates into user topics. </td>
  </tr>
  <tr>
    <td align="right"> 4901 </td>
    <td> Added templates in user webs support </td>
  </tr>
  <tr>
    <td align="right"> 4897 </td>
    <td> Fixes for disabling during preview; re-enabled old legacy parameters </td>
  </tr>
  <tr>
    <td align="right"> 4889 </td>
    <td> Chopped down from PeterMasiar version, removing several parameters, savecomment script, changing way templates are done. Major rewrite, atcherly. </td>
  </tr>
  <tr>
    <td align="right"> 4882 </td>
    <td> Update from PeterMasiar's 2.0 version, plus documentation and small code improvements. </td>
  </tr>
  <tr>
    <td align="right"> 4745 </td>
    <td> 06 Mar 2002 initial commit </td>
  </tr>
  <tr>
    <td align="right"> Perl Version: </td>
    <td> &gt;= 5.6.1 </td>
  </tr>
  <tr>
    <td align="right"> Plugin Home: </td>
    <td> TWiki:Plugins/%TOPIC% </td>
  </tr>
  <tr>
    <td align="right"> Feedback: </td>
    <td> TWiki:Plugins/%TOPIC%Dev </td>
  </tr>
</table>

**_Related Topics:_** [[TWikiPreferences]], [[TWikiPlugins]]

-- TWiki:Main/CrawfordCurrie - 15:45:58 03 March 2007