# Plugin for TWiki Enterprise Collaboration Platform, http://TWiki.org/

 #

 # Copyright (C) 2000-2003 Andrea Sterbini, a.sterbini@flashnet.it

 # Copyright (C) 2001-2006 Peter Thoeny, peter@thoeny.org

 # and TWiki Contributors. All Rights Reserved. TWiki Contributors

 # are listed in the AUTHORS file in the root of this distribution.

 # NOTE: Please extend that file, not this notice.

 #

 # This program is free software; you can redistribute it and/or

 # modify it under the terms of the GNU General Public License

 # as published by the Free Software Foundation; either version 2

 # of the License, or (at your option) any later version. For

 # more details read LICENSE in the root of this distribution.

 #

 # This program is distributed in the hope that it will be useful,

 # but WITHOUT ANY WARRANTY; without even the implied warranty of

 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 #

 # For licensing info read LICENSE file in the TWiki root.

 =pod

 ---+ package EmptyPlugin

 This is an empty TWiki plugin. It is a fully defined plugin, but is

 disabled by default in a TWiki installation. Use it as a template

 for your own plugins; see TWiki.TWikiPlugins for details.

 This version of the !EmptyPlugin documents the handlers supported

 by revision 1.2 of the Plugins API. See the documentation of =TWiki::Func=

 for more information about what this revision number means, and how a

 plugin can check it.

 __NOTE:__ To interact with TWiki use ONLY the official API functions

 in the TWiki::Func module. Do not reference any functions or

 variables elsewhere in TWiki, as these are subject to change

 without prior warning, and your plugin may suddenly stop

 working.

 For increased performance, all handlers except initPlugin are

 disabled below. *To enable a handler* remove the leading DISABLE_ from

 the function name. For efficiency and clarity, you should comment out or

 delete the whole of handlers you don't use before you release your

 plugin.

 __NOTE:__ When developing a plugin it is important to remember that

 TWiki is tolerant of plugins that do not compile. In this case,

 the failure will be silent but the plugin will not be available.

 See %TWIKIWEB%.TWikiPlugins#FAILEDPLUGINS for error messages.

 __NOTE:__ Defining deprecated handlers will cause the handlers to be 

 listed in %TWIKIWEB%.TWikiPlugins#FAILEDPLUGINS. See

 %TWIKIWEB%.TWikiPlugins#Handlig_deprecated_functions

 for information on regarding deprecated handlers that are defined for

 compatibility with older TWiki versions.

 __NOTE:__ When writing handlers, keep in mind that these may be invoked

 on included topics. For example, if a plugin generates links to the current

 topic, these need to be generated before the afterCommonTagsHandler is run,

 as at that point in the rendering loop we have lost the information that we

 the text had been included from another topic.

 =cut

 # change the package name and $pluginName!!!

 package TWiki::Plugins::EmptyPlugin;

 # Always use strict to enforce variable scoping

 use strict;

 require TWiki::Func;    # The plugins API

 require TWiki::Plugins; # For the API version

 # $VERSION is referred to by TWiki, and is the only global variable that

 # *must* exist in this package.

 use vars qw( $VERSION $RELEASE $SHORTDESCRIPTION $debug $pluginName $NO_PREFS_IN_TOPIC );

 # This should always be $Rev: 15942 (22 Jan 2008) $ so that TWiki can determine the checked-in

 # status of the plugin. It is used by the build automation tools, so

 # you should leave it alone.

 $VERSION = '$Rev: 15942 (22 Jan 2008) $';

 # This is a free-form string you can use to "name" your own plugin version.

 # It is *not* used by the build automation tools, but is reported as part

 # of the version number in PLUGINDESCRIPTIONS.

 $RELEASE = 'TWiki-4.2';

 # Short description of this plugin

 # One line description, is shown in the %TWIKIWEB%.TextFormattingRules topic:

 $SHORTDESCRIPTION = 'Empty Plugin used as a template for new Plugins';

 # You must set $NO_PREFS_IN_TOPIC to 0 if you want your plugin to use preferences

 # stored in the plugin topic. This default is required for compatibility with

 # older plugins, but imposes a significant performance penalty, and

 # is not recommended. Instead, use $TWiki::cfg entries set in LocalSite.cfg, or

 # if you want the users to be able to change settings, then use standard TWiki

 # preferences that can be defined in your Main.TWikiPreferences and overridden

 # at the web and topic level.

 $NO_PREFS_IN_TOPIC = 1;

 # Name of this Plugin, only used in this module

 $pluginName = 'EmptyPlugin';

 =pod

 ---++ initPlugin($topic, $web, $user, $installWeb) -> $boolean

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

    * =$user= - the login name of the user

    * =$installWeb= - the name of the web the plugin is installed in

 REQUIRED

 Called to initialise the plugin. If everything is OK, should return

 a non-zero value. On non-fatal failure, should write a message

 using TWiki::Func::writeWarning and return 0. In this case

 %FAILEDPLUGINS% will indicate which plugins failed.

 In the case of a catastrophic failure that will prevent the whole

 installation from working safely, this handler may use 'die', which

 will be trapped and reported in the browser.

 You may also call =TWiki::Func::registerTagHandler= here to register

 a function to handle variables that have standard TWiki syntax - for example,

 =%MYTAG{"my param" myarg="My Arg"}%. You can also override internal

 TWiki variable handling functions this way, though this practice is unsupported

 and highly dangerous!

 __Note:__ Please align variables names with the Plugin name, e.g. if 

 your Plugin is called FooBarPlugin, name variables FOOBAR and/or 

 FOOBARSOMETHING. This avoids namespace issues.

 =cut

 sub initPlugin {

     my( $topic, $web, $user, $installWeb ) = @_;

     # check for Plugins.pm versions

     if( $TWiki::Plugins::VERSION < 1.026 ) {

         TWiki::Func::writeWarning( "Version mismatch between $pluginName and Plugins.pm" );

         return 0;

     }

     # Example code of how to get a preference value, register a variable handler

     # and register a RESTHandler. (remove code you do not need)

     # Set plugin preferences in LocalSite.cfg, like this:

     # $TWiki::cfg{Plugins}{EmptyPlugin}{ExampleSetting} = 1;

     # Always provide a default in case the setting is not defined in

     # LocalSite.cfg. See TWiki.TWikiPlugins for help in adding your plugin

     # configuration to the =configure= interface.

     my $setting = $TWiki::cfg{Plugins}{EmptyPlugin}{ExampleSetting} || 0;

     $debug = $TWiki::cfg{Plugins}{EmptyPlugin}{Debug} || 0;

     # register the _EXAMPLETAG function to handle %EXAMPLETAG{...}%

     # This will be called whenever %EXAMPLETAG% or %EXAMPLETAG{...}% is

     # seen in the topic text.

     TWiki::Func::registerTagHandler( 'EXAMPLETAG', \&_EXAMPLETAG );

     # Allow a sub to be called from the REST interface 

     # using the provided alias

     TWiki::Func::registerRESTHandler('example', \&restExample);

     # Plugin correctly initialized

     return 1;

 }

 # The function used to handle the %EXAMPLETAG{...}% variable

 # You would have one of these for each variable you want to process.

 sub _EXAMPLETAG {

     my($session, $params, $theTopic, $theWeb) = @_;

     # $session  - a reference to the TWiki session object (if you don't know

     #             what this is, just ignore it)

     # $params=  - a reference to a TWiki::Attrs object containing parameters.

     #             This can be used as a simple hash that maps parameter names

     #             to values, with _DEFAULT being the name for the default

     #             parameter.

     # $theTopic - name of the topic in the query

     # $theWeb   - name of the web in the query

     # Return: the result of processing the variable

     # For example, %EXAMPLETAG{'hamburger' sideorder="onions"}%

     # $params->{_DEFAULT} will be 'hamburger'

     # $params->{sideorder} will be 'onions'

 }

 =pod

 ---++ earlyInitPlugin()

 This handler is called before any other handler, and before it has been

 determined if the plugin is enabled or not. Use it with great care!

 If it returns a non-null error string, the plugin will be disabled.

 =cut

 sub DISABLE_earlyInitPlugin {

     return undef;

 }

 =pod

 ---++ initializeUserHandler( $loginName, $url, $pathInfo )

    * =$loginName= - login name recovered from $ENV{REMOTE_USER}

    * =$url= - request url

    * =$pathInfo= - pathinfo from the CGI query

 Allows a plugin to set the username. Normally TWiki gets the username

 from the login manager. This handler gives you a chance to override the

 login manager.

 Return the *login* name.

 This handler is called very early, immediately after =earlyInitPlugin=.

 *Since:* TWiki::Plugins::VERSION = '1.010'

 =cut

 sub DISABLE_initializeUserHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $loginName, $url, $pathInfo ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::initializeUserHandler( $_[0], $_[1] )" ) if $debug;

 }

 =pod

 ---++ registrationHandler($web, $wikiName, $loginName )

    * =$web= - the name of the web in the current CGI query

    * =$wikiName= - users wiki name

    * =$loginName= - users login name

 Called when a new user registers with this TWiki.

 *Since:* TWiki::Plugins::VERSION = '1.010'

 =cut

 sub DISABLE_registrationHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $web, $wikiName, $loginName ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::registrationHandler( $_[0], $_[1] )" ) if $debug;

 }

 =pod

 ---++ commonTagsHandler($text, $topic, $web, $included, $meta )

    * =$text= - text to be processed

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

    * =$included= - Boolean flag indicating whether the handler is invoked on an included topic

    * =$meta= - meta-data object for the topic MAY BE =undef=

 This handler is called by the code that expands %<nop>TAGS% syntax in

 the topic body and in form fields. It may be called many times while

 a topic is being rendered.

 For variables with trivial syntax it is far more efficient to use

 =TWiki::Func::registerTagHandler= (see =initPlugin=).

 Plugins that have to parse the entire topic content should implement

 this function. Internal TWiki

 variables (and any variables declared using =TWiki::Func::registerTagHandler=)

 are expanded _before_, and then again _after_, this function is called

 to ensure all %<nop>TAGS% are expanded.

 __NOTE:__ when this handler is called, <verbatim> blocks have been

 removed from the text (though all other blocks such as <pre> and

 <noautolink> are still present).

 __NOTE:__ meta-data is _not_ embedded in the text passed to this

 handler. Use the =$meta= object.

 *Since:* $TWiki::Plugins::VERSION 1.000

 =cut

 sub DISABLE_commonTagsHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $text, $topic, $web, $meta ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::commonTagsHandler( $_[2].$_[1] )" ) if $debug;

     # do custom extension rule, like for example:

     # $_[0] =~ s/%XYZ%/&handleXyz()/ge;

     # $_[0] =~ s/%XYZ{(.*?)}%/&handleXyz($1)/ge;

 }

 =pod

 ---++ beforeCommonTagsHandler($text, $topic, $web, $meta )

    * =$text= - text to be processed

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

    * =$meta= - meta-data object for the topic MAY BE =undef=

 This handler is called before TWiki does any expansion of it's own

 internal variables. It is designed for use by cache plugins. Note that

 when this handler is called, <verbatim> blocks are still present

 in the text.

 __NOTE__: This handler is called once for each call to

 =commonTagsHandler= i.e. it may be called many times during the

 rendering of a topic.

 __NOTE:__ meta-data is _not_ embedded in the text passed to this

 handler.

 __NOTE:__ This handler is not separately called on included topics.

 =cut

 sub DISABLE_beforeCommonTagsHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $text, $topic, $web, $meta ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::beforeCommonTagsHandler( $_[2].$_[1] )" ) if $debug;

 }

 =pod

 ---++ afterCommonTagsHandler($text, $topic, $web, $meta )

    * =$text= - text to be processed

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

    * =$meta= - meta-data object for the topic MAY BE =undef=

 This handler is after TWiki has completed expansion of %TAGS%.

 It is designed for use by cache plugins. Note that when this handler

 is called, <verbatim> blocks are present in the text.

 __NOTE__: This handler is called once for each call to

 =commonTagsHandler= i.e. it may be called many times during the

 rendering of a topic.

 __NOTE:__ meta-data is _not_ embedded in the text passed to this

 handler.

 =cut

 sub DISABLE_afterCommonTagsHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $text, $topic, $web, $meta ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::afterCommonTagsHandler( $_[2].$_[1] )" ) if $debug;

 }

 =pod

 ---++ preRenderingHandler( $text, \%map )

    * =$text= - text, with the head, verbatim and pre blocks replaced with placeholders

    * =\%removed= - reference to a hash that maps the placeholders to the removed blocks.

 Handler called immediately before TWiki syntax structures (such as lists) are

 processed, but after all variables have been expanded. Use this handler to 

 process special syntax only recognised by your plugin.

 Placeholders are text strings constructed using the tag name and a 

 sequence number e.g. 'pre1', "verbatim6", "head1" etc. Placeholders are 

 inserted into the text inside <!--!marker!--> characters so the 

 text will contain <!--!pre1!--> for placeholder pre1.

 Each removed block is represented by the block text and the parameters 

 passed to the tag (usually empty) e.g. for

 <verbatim>

 <pre class='slobadob'>

 XYZ

 </pre>

 the map will contain:

 <pre>

 $removed->{'pre1'}{text}:   XYZ

 $removed->{'pre1'}{params}: class="slobadob"

 </pre>

 Iterating over blocks for a single tag is easy. For example, to prepend a 

 line number to every line of every pre block you might use this code:

 <verbatim>

 foreach my $placeholder ( keys %$map ) {

     if( $placeholder =~ /^pre/i ) {

        my $n = 1;

        $map->{$placeholder}{text} =~ s/^/$n++/gem;

     }

 }

 </verbatim>

 __NOTE__: This handler is called once for each rendered block of text i.e. 

 it may be called several times during the rendering of a topic.

 __NOTE:__ meta-data is _not_ embedded in the text passed to this

 handler.

 Since TWiki::Plugins::VERSION = '1.026'

 =cut

 sub DISABLE_preRenderingHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     #my( $text, $pMap ) = @_;

 }

 =pod

 ---++ postRenderingHandler( $text )

    * =$text= - the text that has just been rendered. May be modified in place.

 __NOTE__: This handler is called once for each rendered block of text i.e. 

 it may be called several times during the rendering of a topic.

 __NOTE:__ meta-data is _not_ embedded in the text passed to this

 handler.

 Since TWiki::Plugins::VERSION = '1.026'

 =cut

 sub DISABLE_postRenderingHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     #my $text = shift;

 }

 =pod

 ---++ beforeEditHandler($text, $topic, $web )

    * =$text= - text that will be edited

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

 This handler is called by the edit script just before presenting the edit text

 in the edit box. It is called once when the =edit= script is run.

 __NOTE__: meta-data may be embedded in the text passed to this handler 

 (using %META: tags)

 *Since:* TWiki::Plugins::VERSION = '1.010'

 =cut

 sub DISABLE_beforeEditHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $text, $topic, $web ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::beforeEditHandler( $_[2].$_[1] )" ) if $debug;

 }

 =pod

 ---++ afterEditHandler($text, $topic, $web, $meta )

    * =$text= - text that is being previewed

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

    * =$meta= - meta-data for the topic.

 This handler is called by the preview script just before presenting the text.

 It is called once when the =preview= script is run.

 __NOTE:__ this handler is _not_ called unless the text is previewed.

 __NOTE:__ meta-data is _not_ embedded in the text passed to this

 handler. Use the =$meta= object.

 *Since:* $TWiki::Plugins::VERSION 1.010

 =cut

 sub DISABLE_afterEditHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $text, $topic, $web ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::afterEditHandler( $_[2].$_[1] )" ) if $debug;

 }

 =pod

 ---++ beforeSaveHandler($text, $topic, $web, $meta )

    * =$text= - text _with embedded meta-data tags_

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

    * =$meta= - the metadata of the topic being saved, represented by a TWiki::Meta object.

 This handler is called each time a topic is saved.

 __NOTE:__ meta-data is embedded in =$text= (using %META: tags). If you modify

 the =$meta= object, then it will override any changes to the meta-data

 embedded in the text. Modify *either* the META in the text *or* the =$meta=

 object, never both. You are recommended to modify the =$meta= object rather

 than the text, as this approach is proof against changes in the embedded

 text format.

 *Since:* TWiki::Plugins::VERSION = '1.010'

 =cut

 sub DISABLE_beforeSaveHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $text, $topic, $web ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::beforeSaveHandler( $_[2].$_[1] )" ) if $debug;

 }

 =pod

 ---++ afterSaveHandler($text, $topic, $web, $error, $meta )

    * =$text= - the text of the topic _excluding meta-data tags_

      (see beforeSaveHandler)

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

    * =$error= - any error string returned by the save.

    * =$meta= - the metadata of the saved topic, represented by a TWiki::Meta object 

 This handler is called each time a topic is saved.

 __NOTE:__ meta-data is embedded in $text (using %META: tags)

 *Since:* TWiki::Plugins::VERSION 1.025

 =cut

 sub DISABLE_afterSaveHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $text, $topic, $web, $error, $meta ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::afterSaveHandler( $_[2].$_[1] )" ) if $debug;

 }

 =pod

 ---++ afterRenameHandler( $oldWeb, $oldTopic, $oldAttachment, $newWeb, $newTopic, $newAttachment )

    * =$oldWeb= - name of old web

    * =$oldTopic= - name of old topic (empty string if web rename)

    * =$oldAttachment= - name of old attachment (empty string if web or topic rename)

    * =$newWeb= - name of new web

    * =$newTopic= - name of new topic (empty string if web rename)

    * =$newAttachment= - name of new attachment (empty string if web or topic rename)

 This handler is called just after the rename/move/delete action of a web, topic or attachment.

 *Since:* TWiki::Plugins::VERSION = '1.11'

 =cut

 sub DISABLE_afterRenameHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ### my ( $oldWeb, $oldTopic, $oldAttachment, $newWeb, $newTopic, $newAttachment ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::afterRenameHandler( " .

                              "$_[0].$_[1] $_[2] -> $_[3].$_[4] $_[5] )" ) if $debug;

 }

 =pod

 ---++ beforeAttachmentSaveHandler(\%attrHash, $topic, $web )

    * =\%attrHash= - reference to hash of attachment attribute values

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

 This handler is called once when an attachment is uploaded. When this

 handler is called, the attachment has *not* been recorded in the database.

 The attributes hash will include at least the following attributes:

    * =attachment= => the attachment name

    * =comment= - the comment

    * =user= - the user id

    * =tmpFilename= - name of a temporary file containing the attachment data

 *Since:* TWiki::Plugins::VERSION = 1.025

 =cut

 sub DISABLE_beforeAttachmentSaveHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ###   my( $attrHashRef, $topic, $web ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::beforeAttachmentSaveHandler( $_[2].$_[1] )" ) if $debug;

 }

 =pod

 ---++ afterAttachmentSaveHandler(\%attrHash, $topic, $web, $error )

    * =\%attrHash= - reference to hash of attachment attribute values

    * =$topic= - the name of the topic in the current CGI query

    * =$web= - the name of the web in the current CGI query

    * =$error= - any error string generated during the save process

 This handler is called just after the save action. The attributes hash

 will include at least the following attributes:

    * =attachment= => the attachment name

    * =comment= - the comment

    * =user= - the user id

 *Since:* TWiki::Plugins::VERSION = 1.025

 =cut

 sub DISABLE_afterAttachmentSaveHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     ###   my( $attrHashRef, $topic, $web ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::afterAttachmentSaveHandler( $_[2].$_[1] )" ) if $debug;

 }

 =begin twiki

 ---++ beforeMergeHandler( $text, $currRev, $currText, $origRev, $origText, $web, $topic )

    * =$text= - the new text of the topic

    * =$currRev= - the number of the most recent rev of the topic in the store

    * =$currText= - the text of that rev

    * =$origRev= - the number of the rev that the edit started on (or undef

      if that revision was overwritten by a replace-revision save)

    * =$origText= - the text of that revision (or undef)

    * =$web= - the name of the web for the topic being saved

    * =$topic= - the name of the topic

 This handler is called immediately before a merge of a topic that was edited

 simultaneously by two users. It is called once on the topic text from

 the =save= script. See =mergeHandler= for handling individual changes in the

 topic text (and in forms).

 =cut

 sub DISABLE_beforeMergeHandler {

     # do not uncomment, use $_[0], $_[1]... instead

     #my( $text, $currRev, $currText, $origRev, $origText, $web, $topic ) = @_;

 }

 =pod

 ---++ mergeHandler( $diff, $old, $new, \%info ) -> $text

 Try to resolve a difference encountered during merge. The =differences= 

 array is an array of hash references, where each hash contains the 

 following fields:

    * =$diff= => one of the characters '+', '-', 'c' or ' '.

       * '+' - =new= contains text inserted in the new version

       * '-' - =old= contains text deleted from the old version

       * 'c' - =old= contains text from the old version, and =new= text

         from the version being saved

       * ' ' - =new= contains text common to both versions, or the change

         only involved whitespace

    * =$old= => text from version currently saved

    * =$new= => text from version being saved

    * =\%info= is a reference to the form field description { name, title,

      type, size, value, tooltip, attributes, referenced }. It must _not_

      be wrtten to. This parameter will be undef when merging the body

      text of the topic.

 Plugins should try to resolve differences and return the merged text. 

 For example, a radio button field where we have 

 ={ diff=>'c', old=>'Leafy', new=>'Barky' }= might be resolved as 

 ='Treelike'=. If the plugin cannot resolve a difference it should return 

 undef.

 The merge handler will be called several times during a save; once for 

 each difference that needs resolution.

 If any merges are left unresolved after all plugins have been given a 

 chance to intercede, the following algorithm is used to decide how to 

 merge the data:

    1 =new= is taken for all =radio=, =checkbox= and =select= fields to 

      resolve 'c' conflicts

    1 '+' and '-' text is always included in the the body text and text

      fields

    1 =<del>conflict</del> <ins>markers</ins>= are used to 

      mark 'c' merges in text fields

 The merge handler is called whenever a topic is saved, and a merge is 

 required to resolve concurrent edits on a topic.

 *Since:* TWiki::Plugins::VERSION = 1.1

 =cut

 sub DISABLE_mergeHandler {

 }

 =pod

 ---++ modifyHeaderHandler( \%headers, $query )

    * =\%headers= - reference to a hash of existing header values

    * =$query= - reference to CGI query object

 Lets the plugin modify the HTTP headers that will be emitted when a

 page is written to the browser. \%headers= will contain the headers

 proposed by the core, plus any modifications made by other plugins that also

 implement this method that come earlier in the plugins list.

 <verbatim>

 $headers->{expires} = '+1h';

 </verbatim>

 Note that this is the HTTP header which is _not_ the same as the HTML

 <HEAD> tag. The contents of the <HEAD> tag may be manipulated

 using the =TWiki::Func::addToHEAD= method.

 *Since:* TWiki::Plugins::VERSION 1.1

 =cut

 sub DISABLE_modifyHeaderHandler {

     my ( $headers, $query ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::modifyHeaderHandler()" ) if $debug;

 }

 =pod

 ---++ redirectCgiQueryHandler($query, $url )

    * =$query= - the CGI query

    * =$url= - the URL to redirect to

 This handler can be used to replace TWiki's internal redirect function.

 If this handler is defined in more than one plugin, only the handler

 in the earliest plugin in the INSTALLEDPLUGINS list will be called. All

 the others will be ignored.

 *Since:* TWiki::Plugins::VERSION 1.010

 =cut

 sub DISABLE_redirectCgiQueryHandler {

     # do not uncomment, use $_[0], $_[1] instead

     ### my ( $query, $url ) = @_;

     TWiki::Func::writeDebug( "- ${pluginName}::redirectCgiQueryHandler( query, $_[1] )" ) if $debug;

 }

 =pod

 ---++ renderFormFieldForEditHandler($name, $type, $size, $value, $attributes, $possibleValues) -> $html

 This handler is called before built-in types are considered. It generates 

 the HTML text rendering this form field, or false, if the rendering 

 should be done by the built-in type handlers.

    * =$name= - name of form field

    * =$type= - type of form field (checkbox, radio etc)

    * =$size= - size of form field

    * =$value= - value held in the form field

    * =$attributes= - attributes of form field 

    * =$possibleValues= - the values defined as options for form field, if

      any. May be a scalar (one legal value) or a ref to an array

      (several legal values)

 Return HTML text that renders this field. If false, form rendering

 continues by considering the built-in types.

 *Since:* TWiki::Plugins::VERSION 1.1

 Note that since TWiki-4.2, you can also extend the range of available

 types by providing a subclass of =TWiki::Form::FieldDefinition= to implement

 the new type (see =TWiki::Plugins.JSCalendarContrib= and

 =TWiki::Plugins.RatingContrib= for examples). This is the preferred way to

 extend the form field types, but does not work for TWiki < 4.2.

 =cut

 sub DISABLE_renderFormFieldForEditHandler {

 }

 =pod

 ---++ renderWikiWordHandler($linkText, $hasExplicitLinkLabel, $web, $topic) -> $linkText

    * =$linkText= - the text for the link i.e. for =[<nop>[Link][blah blah]]=

      it's =blah blah=, for =BlahBlah= it's =BlahBlah=, and for [[Blah Blah]] it's =Blah Blah=.

    * =$hasExplicitLinkLabel= - true if the link is of the form =[<nop>[Link][blah blah]]= (false if it's ==<nop>[Blah]] or =BlahBlah=)

    * =$web=, =$topic= - specify the topic being rendered (only since TWiki 4.2)

 Called during rendering, this handler allows the plugin a chance to change

 the rendering of labels used for links.

 Return the new link text.

 *Since:* TWiki::Plugins::VERSION 1.1

 =cut

 sub DISABLE_renderWikiWordHandler {

     my( $linkText, $hasExplicitLinkLabel, $web, $topic ) = @_;

     return $linkText;

 }

 =pod

 ---++ completePageHandler($html, $httpHeaders)

 This handler is called on the ingredients of every page that is

 output by the standard TWiki scripts. It is designed primarily for use by

 cache and security plugins.

    * =$html= - the body of the page (normally <html>..$lt;/html>)

    * =$httpHeaders= - the HTTP headers. Note that the headers do not contain

      a =Content-length=. That will be computed and added immediately before

      the page is actually written. This is a string, which must end in \n\n.

 *Since:* TWiki::Plugins::VERSION 1.2

 =cut

 sub DISABLE_completePageHandler {

     #my($html, $httpHeaders) = @_;

     # modify $_[0] or $_[1] if you must change the HTML or headers

 }

 =pod

 ---++ restExample($session) -> $text

 This is an example of a sub to be called by the =rest= script. The parameter is:

    * =$session= - The TWiki object associated to this session.

 Additional parameters can be recovered via de query object in the $session.

 For more information, check TWiki:TWiki.TWikiScripts#rest

 *Since:* TWiki::Plugins::VERSION 1.1

 =cut

 sub restExample {

    #my ($session) = @_;

    return "This is an example of a REST invocation\n\n";

 }

 1;