LikePlugin

Like-style voting for content

This plugin lets you vote on topics, attachments and comments by means of a like or a dislike . All "likes" are stored within Foswiki, that is: they are not stored with the help of an external social platform such as Facebook or the like. In fact, only then will this feature make sense on an intranet install where no external information is supposed to be leaked to the outside world for obvious reasons.

Likes are used for social filtering, to

• list the most liked contributions on a frontpage (requires DBCachePlugin),
• influence the sorting order of search results (requires SolrPlugin),
• vote on comments and optionally hide comments that fall below a lower threshold (requires MetaCommentPlugin)
• vote on attachments (requires TopicInteractionPlugin).

Like buttons are highly customizable coming with a set of look and feels to match common css frameworks such as jquery-ui or flat design.

In general, there are two different kinds of Likes

• youtube style: you may vote thumb up and down
• facebook style: only positive likes are collected.

Note that this plugin does not implement a star rating. Use the social rating feature of SocialFormfieldsPlugin.

Examples

You type	You get
%LIKE{theme="simple"}%	I like this0 I don't like this0
%LIKE{theme="default"}%	I like this0 I don't like this0
%LIKE{theme="lightgray"}%	I like this0 I don't like this0
%LIKE{theme="gray"}%	I like this0 I don't like this0
%LIKE{theme="black"}%	I like this0 I don't like this0
%LIKE{theme="padding"}%	I like this0 I don't like this0
%LIKE{theme="ui"}%	I like this0 I don't like this0
%LIKE{theme="pattern"}%	I like this0 I don't like this0
%LIKE{theme="flat"}%	I like this0 I don't like this0
%LIKE{ theme="simple" showdislike="off" showcount="off" likeicon="fa-thumbs-o-up fa-flip-horizontal fa-lg" likelabel="Like" likedlabel="Liked" }%	Like
%LIKE{ theme="simple" showlabel="off" }%	0 0
%LIKE{ likeicon="heart" showdislike="off" likelabel="This was helpful" likedlabel="I found this helpful" theme="padding" }%	This was helpful0
%LIKE{ theme="simple" showlabel="off" likeicon="heart" dislikeicon="cross" }%	0 0
%LIKE{ theme="ui" likelabel="Agree" likedlabel="Agreed" dislikelabel="" }%	Agree0 0
%LIKE{ theme="ui" showlabel="off" }%	0 0

Syntax

Here's the full syntax of all options of the %LIKE macro.

The format, likeformat and dislikeformat parameters may come with a set of variables to display current values as follows:

Variable	Description
%like%	used in format to insert the result of likeformat
%dislike%	used in format to insert the result of dislikeformat
%params%	used in format to insert the html5 data attributes for the jquery like plugin
%likeLabel%, %likedLabel%, %dislikeLabel%, %dislikedLabel%	labels of the like/dislike buttons
%thisLikeLabel%	current value to be used; this is either the likelabel or the likedlabel of the current state
%thisDislikeLabel%	current value to be used; this is either the dislikelabel or the dislikedlabel of the current state
%likeIcon%, %dislikeIcon%	value of likeicon and dislikeicon
%likeCount%, %dislikeCount%, %totalLikeCount%	current counts of votes done by all users
%likeSelected%, %dislikeSelected%	either empty or the string "selected" depending on the state of the button
%editable%	either the string "editable" or empty depending on the mode of the widget
%web%	web of the current object being voted on
%topic%	topic of the current object being voted on
%metaType%	meta type
%metaId%	meta id
%class%	the custom class string

Perl API

The plugin a registration handler that other plugins may contact in order to be notified whenever a user liked an object.

registerAfterLikeHandler()

Example:

use Foswiki::Plugins::LikePlugin();

Foswiki::LikePlugin::registerAfterLikeHandler(sub {
  my ($web, $topic, $type, $id, $user, $likes, $dislikes) = @_;

});

For example MetaCommentPlugin updates the META:COMMENT data to cache like and dislike counts as part of the meta data to be able to seamlessly sort and hide comments based on likes.

getCore()

This function offers access to the core singleton object responsible for like/dislike services.

Example:

use Foswiki::Plugins::LikePlugin();

my $likeCore = Foswiki::Plugins::LikePlugin::getCore();
my ($likes, $dislikes) = $likeCore->getLikes($web, $topic, $type, $id);
my ($myLikes, $myDislikes) = $likeCore->getLikesOfUser($web, $topic, $type, $id, $wikiName);

JavaScript API

Each %LIKE macro will be powered by a piece of jQuery to communicate with the backend counting likes and dislikes. This is done using a vote JSON-RPC handler that takes the following parameters:

Parameter	Description
web, topic	address of the object to be liked
type	meta data type, e.g. COMMENT or FILEATTACHMENT
id	name of the meta data to be voted on
username	username that the vote is counted for (only for testing and admins)
like	the vote; possible values are 0 or 1
dislike	the vote; possible values are 0 or 1

A change.likes event is emitted Whenever a user votes. This allows you to listen to a %LIKE widget and be notified on any vote event. All %LIKE widgets on the same page are listening on this change.likes event and update themselves whenever another widget for the same object has been updated. You may notice that when installing this plugin and testing the above examples that clicking on one button will update all others simultaneously as long as they refer to the same object being voted on.

Installation Instructions

You do not need to install anything in the browser to use this extension. The following instructions are for the administrator who installs the extension on the server.

Open configure, and open the "Extensions" section. "Extensions Operation and Maintenance" Tab -> "Install, Update or Remove extensions" Tab. Click the "Search for Extensions" button. Enter part of the extension name or description and press search. Select the desired extension(s) and click install. If an extension is already installed, it will not show up in the search results.

You can also install from the shell by running the extension installer as the web server user: (Be sure to run as the webserver user, not as root!)

cd /path/to/foswiki
perl tools/extension_installer <NameOfExtension> install

If you have any problems, or if the extension isn't available in configure, then you can still install manually from the command-line. See https://foswiki.org/Support/ManuallyInstallingExtensions for more help.

Note that you will need a database driver for the DBI interface used to store values into an SQL database backend. By default SQLite is used.

Skin integration

NatSkin

LikePlugin is well integrated into NatSkin so that no further customizations are required. Topics are like-enabled by displaying a "thumb-up" as part of the topic actions. You may further customize the location of the like button in the SiteTopicActions web component.

PatternSkin

To enable topic-voting add the like identifier to the SKIN setting, e.g.

   * Set SKIN = like, natedit, pattern

In case you've got BreadcrumbsPlugin, TopicInteractionPlugin and/or SolrPlugin then use

   * Set SKIN = like, breadcrumbs, solr, topicinteraction, natedit, pattern

Dependencies

Name	Version	Description
DBI	>=1.0	Required
DBD::SQLite	>=1.54	Recommended.
Foswiki::Plugins::JQueryPlugin	>=6.00	Required
Foswiki::Contrib::JsonRpcContrib	>=2.21	Required
Foswiki::Plugins::DBCachePlugin	>=8.10	Optional
Foswiki::Plugins::SolrPlugin	>=4.10	Optional

Change History

18 Nov 2019	added likeiconformat and dislikeiconformat paramerters
02 Sep 2016	add support for fontawesome icon; initial support for WebSocketPlugin
15 Oct 2015	normalize web before putting it into an sql query ... fixes counts in subwebs
21 Sep 2015	initial release