Extension:CategoryCloud

This extensions adds the ability to create a tag cloud to a wiki site. It generates a tag for every sub-category, but not article, in the given category. The top-level category is not included and the extension does not recursively go through the sub-categories for additional categories.

The size of the individual tags are based on the number of children, both category and articles, of each sub-category. These are normalized against the other counts and then rendered based on relative size. This list is built on a single SQL query against two indexed tables, so it should remain speedy even on larger sites.

This extension can be used in two different manners: 

The category may be anything, but the "Category:" is assumed. There are a few optional attributes in the extension.


 * minsize: The font size, in percentage, that the small category will have. Defaults to 80.
 * maxsize: The font size, also as a percentage, that the largest category will have. Defaults to 125.
 * order: The order of the categories. Defaults to "name" but may also be "count".
 * class: A CSS class to put into the outer div generated.
 * style: The contents of this optional attribute will be placed in a style attribute of the outermost div tag.

Examples of the attributes:



Examples of CategoryCloud
The following sites use CategoryCloud:


 * http://moonfire.us/ - The author's personal website.
 * http://www.stressipedia.de - chilly page where you can have much fun

Source Code
The source code may be accessed via SVN or the latest version can be found here:  tag to wiki markup. The * following attributes are used: *   category = The category, minus the "Category:" *   minsize = The minimum size, as percentage. Defaults to 80. *   maxsize = The maximum size, as a percentage. Defaults to 125. *   class = The CSS class to assign to the outer div, defaults *           to "category-cloud" * * There is also a parser function that uses * with optional parameters being includes as "|param=value". * * @addtogroup Extensions * @author Dylan R. E. Moonfire  * @copyright © 2007 Dylan R. E. Moonfire * @licence GNU General Public Licence 2.0 */

// Make sure we are being properly if( !defined( 'MEDIAWIKI' ) ) { echo( "This file is an extension to the MediaWiki software "		. "and cannot be used standalone.\n" ); die( -1 ); }

// Hook up into MediaWiki $wgExtensionFunctions[] = 'categoryCloud'; $wgHooks['LanguageGetMagic'][]	= 'categoryCloudMagic'; $wgExtensionCredits['parserhook'][] = array(   'name' => 'Category Cloud',    'author' => 'Dylan R. E. Moonfire',    'description' => 'Create a tag cloud using categories.',    'url' => 'http://www.mediawiki.org/wiki/Extension:CategoryCloud',    'version' => '0.4.0' );

function categoryCloud {       global $wgParser, $wgMessageCache;

// Set the hooks $wgParser->setHook('category-cloud', 'categoryCloudRender'); $wgParser->setFunctionHook('category-cloud', 'categoryCloudFunction');

// Set our messages $wgMessageCache->addMessages( array( 'categorycloud_missingcategory' => 'CategoryCloud: Cannot find category attribute', 'categorycloud_emptycategory' => 'CategoryCloud: Category is empty: ', 'categorycloud_cannotparse' => 'CategoryCloud: Cannot parse parameter: ', )); }

// This manipulates the results of the CategoryCloud extension // into the same function as the  tag. function categoryCloudFunction($parser) {	// Get the arguments $fargs = func_get_args; $input = array_shift($fargs);

// The first category is required $category = array_shift($fargs); $params = array; $params["category"] = $category; $params["donotparse"] = 1;

// Split the rest of the arguments foreach ($fargs as $parm) {		// Split it into its components $split = split("=", $parm);

if (!$split[1]) {			return htmlspecialchars(wfMsg( 'categorycloud_cannotparse')				. $parm); }

// Save it		$params[$split[0]] = $split[1]; }

// Return the cloud return categoryCloudRender($input, $params, $parser); }

// Sets up the magic for the parser functions function categoryCloudMagic(&$magicWords, $langCode) {	$magicWords['category-cloud'] = array(0, 'category-cloud'); return true; }

// The actual processing function categoryCloudRender($input, $args, &$parser) {	// Imports global $wgOut;

// Profiling wfProfileIn('CategoryCloud::Render');

// Disable the cache, otherwise the cloud will only update // itself when a user edits and saves the page. $parser->disableCache;

// Get the database handler and specific controls $dbr =& wfGetDB( DB_SLAVE ); $pageTable = $dbr->tableName('page'); $categoryLinksTable = $dbr->tableName('categorylinks');

// Normalize the order $order = "name"; if (array_key_exists("order", $args)) $order = $args["order"];

if ($order != "count") $order = "name"; else // we want reverse $order = "count desc";

// Get the list of the subcategories and the number of children if (!array_key_exists("category", $args)) {		return htmlspecialchars(wfMsg( 'categorycloud_missingcategory')); }

$categoryName = $args["category"];

// Build up an SQL of everything $categoryNamespace = 14; $sql = "SELECT p1.page_title as name, count(*) as count " . "FROM $categoryLinksTable cl, $categoryLinksTable cl2, " . " $pageTable p1, $pageTable p2 " . "WHERE cl.cl_to = ". $dbr->addQuotes($categoryName) . " AND cl.cl_from = p1.page_id " . " AND cl2.cl_to  = p1.page_title " . " AND cl2.cl_from = p2.page_id " . " AND p1.page_namespace = $categoryNamespace " . " AND p1.page_id != p2.page_id " . "GROUP BY p1.page_title " . "ORDER BY $order"; $res = $dbr->query($sql);

if ($dbr->numRows( $res ) == 0) {		// Can't find category return htmlspecialchars(wfMsg( 'categorycloud_emptycategory')			. $categoryName); }

// Build up an array and keep track of mins and maxes $minCount = -1; $maxCount = -1; $countAll = 0; $total = 0; $categories = array; $names = array;

while ($row = $dbr->fetchObject($res)) {		// Pull out the fields $name = $row->name; $count = $row->count;

// Add it to the array and keep track of min/max $categories[$name] = $count; $names[] = $name; $countAll++; $total += $count; if ($minCount < 0 || $minCount > $count) $minCount = $count;

if ($maxCount < 0 || $maxCount < $count) $maxCount = $count; }

// Figure out the averages and font sizes $minSize = 80; $maxSize = 125;

if (array_key_exists("minsize", $args)) $minSize = $args["minsize"]; if (array_key_exists("maxsize", $args)) $maxSize = $args["maxsize"];

$countDelta = $maxCount - $minCount; $sizeDelta = $maxSize - $minSize; $average = $total / $countAll;

// Create the tag cloud div $class = "category-cloud";

if ($args["class"]) $class = $args["class"];

$text = "";

// Go through the categories by name foreach ($names as $cat) {		// Wrap the link in a size if ($countDelta == 0) $size = 100; else $size = (($categories[$cat] - $minCount)				* $sizeDelta / $countDelta) + $minSize;

// Get the link $cat = str_replace("_", " ", $cat); $text .= " " . "$cat "; }

// Finish up	$text .= " ";

// If donotparse is set to a value, then we don't want // to parse it into wiki text. if (array_key_exists("donotparse", $args)) {	       wfProfileOut('CategoryCloud::RenderNoParse'); return $text; }

// Parse the results into wiki text $output = $parser->parse($text,			$parser->mTitle, $parser->mOptions,			true, false);

// Finish up and return the results wfProfileOut('CategoryCloud::Render'); return $output->getText; } ?>