Brian Wolff has uploaded a new change for review.
https://gerrit.wikimedia.org/r/71997
Change subject: Add Special:RandomInCategory.
......................................................................
Add Special:RandomInCategory.
This is meant mostly to spur discussion. The method used is quite
biased, but I believe its the best possible without a schema change
and still being efficient.
The question at hand - is this method acceptable. The method used
is to chose a random timestamp and look at cl_timestamp. This method
will give good results if the timestamps are uniformly distributed
(which probably is not usually true). I think it may give acceptable
results in general, especially given most people are not interested
in true randomness, but more in "give me a result I haven't seen before".
(For example, to pick a random entry in a maintenance category to clean
up).
It also fudges the result a little bit using offset to stop really
biased results from happening.
Bug: 25931
Change-Id: I0c48e4a236b50fb627af94f0df47fef8372ea14d
---
M RELEASE-NOTES-1.22
M includes/AutoLoader.php
M includes/SpecialPageFactory.php
A includes/specials/SpecialRandomInCategory.php
M languages/messages/MessagesEn.php
M languages/messages/MessagesQqq.php
M maintenance/language/messages.inc
7 files changed, 291 insertions(+), 0 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/mediawiki/core
refs/changes/97/71997/1
diff --git a/RELEASE-NOTES-1.22 b/RELEASE-NOTES-1.22
index 45a6f01..0d06ff2 100644
--- a/RELEASE-NOTES-1.22
+++ b/RELEASE-NOTES-1.22
@@ -137,6 +137,7 @@
also granting the ability to protect and unprotect.
* (bug 48256) Make brackets in section edit links accessible to CSS.
They are now wrapped in <span class="mw-editsection-bracket" />.
+* (bug 25931) Add Special:RandomInCategory.
=== Bug fixes in 1.22 ===
* Disable Special:PasswordReset when $wgEnableEmail is false. Previously one
diff --git a/includes/AutoLoader.php b/includes/AutoLoader.php
index 6f8cd4b..09d5f90 100644
--- a/includes/AutoLoader.php
+++ b/includes/AutoLoader.php
@@ -932,6 +932,7 @@
'ProtectedPagesPager' => 'includes/specials/SpecialProtectedpages.php',
'ProtectedTitlesPager' =>
'includes/specials/SpecialProtectedtitles.php',
'RandomPage' => 'includes/specials/SpecialRandompage.php',
+ 'RandomInCategory' => 'includes/specials/SpecialRandomInCategory.php',
'ShortPagesPage' => 'includes/specials/SpecialShortpages.php',
'SpecialActiveUsers' => 'includes/specials/SpecialActiveusers.php',
'SpecialAllmessages' => 'includes/specials/SpecialAllmessages.php',
diff --git a/includes/SpecialPageFactory.php b/includes/SpecialPageFactory.php
index 4d63553..c4b3dd0 100644
--- a/includes/SpecialPageFactory.php
+++ b/includes/SpecialPageFactory.php
@@ -130,6 +130,7 @@
// Redirecting special pages
'LinkSearch' => 'LinkSearchPage',
'Randompage' => 'Randompage',
+ 'RandomInCategory' => 'RandomInCategory',
'Randomredirect' => 'SpecialRandomredirect',
// High use pages
diff --git a/includes/specials/SpecialRandomInCategory.php
b/includes/specials/SpecialRandomInCategory.php
new file mode 100644
index 0000000..3b2f964
--- /dev/null
+++ b/includes/specials/SpecialRandomInCategory.php
@@ -0,0 +1,264 @@
+<?php
+/**
+ * Implements Special:RandomInCategory
+ *
+ * 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.
+ *
+ * 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. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup SpecialPage
+ * @author Brian Wolff
+ */
+
+/**
+ * Special page to direct the user to a random page
+ *
+ * @note The method used here is rather biased. It is assumed that
+ * the use of this page will be people wanting to get a random page
+ * out of a maintenance category, to fix it up. The method used by
+ * this page should return different pages in an unpredictable fashion
+ * which is hoped to be sufficient, even if some pages are selected
+ * more often than others.
+ *
+ * A more unbiased method could be achieved by adding a cl_random field
+ * to the categorylinks table.
+ *
+ * The method used here is as follows:
+ * * Find the smallest and largest timestamp in the category
+ * * Pick a random timestamp in between
+ * * Pick an offset between 0 and 30
+ * * Get the offset'ed page that is newer than the timestamp selected
+ * The offset is meant to counter the fact the timestamps aren't usually
+ * uniformly distributed, so if things are very non-uniform at least we
+ * won't have the same page selected 99% of the time.
+ *
+ * @ingroup SpecialPage
+ */
+class RandomInCategory extends SpecialPage {
+ protected $extra = array(); // Extra SQL statements
+ protected $category = false; // Title object of category
+ protected $maxOffset = 30; // Max amount to fudge randomness by.
+ private $maxTimestamp = null;
+ private $minTimestamp = null;
+
+ public function __construct( $name = 'RandomInCategory' ) {
+ parent::__construct( $name );
+ }
+
+ /**
+ * Set which category to use.
+ * @param Title $cat
+ */
+ public function setCategory( Title $cat ) {
+ $this->category = $cat;
+ $this->maxTimestamp = null;
+ $this->minTimestamp = null;
+ }
+
+ public function execute( $par ) {
+ $cat = false;
+
+ $categoryStr = $this->getRequest()->getText( 'category', $par );
+
+ if ( $categoryStr ) {
+ $cat = Title::newFromText( $categoryStr, NS_CATEGORY );
+ }
+
+ if ( $cat ) {
+ $this->setCategory( $cat );
+ }
+
+
+ if ( !$this->category && $categoryStr ) {
+ $this->setHeaders();
+ // For grep: uses message
randomincategory-invalidcategory
+ $this->getOutput()->addWikiMsg( strtolower(
$this->getName() ) . '-invalidcategory',
+ wfEscapeWikiText( $categoryStr ) );
+
+ return;
+ } elseif ( !$this->category ) {
+ $this->setHeaders();
+ // For grep: uses message
randomincategory-selectcategory, randomincategory-selectcategory-submit.
+ $input = Html::input( 'category' );
+ $submitText = wfMessage( strtolower( $this->getName() )
. '-selectcategory-submit' )->text();
+ $submit = Html::input( '', $submitText, 'submit' );
+
+ $msg = $this->msg( strtolower( $this->getName() ) .
'-selectcategory' );
+ $form = Html::rawElement( 'form', array( 'action' =>
$this->getTitle()->getLocalUrl() ),
+ $msg->rawParams( $input, $submit )->parse()
+ );
+ $this->getOutput()->addHtml( $form );
+
+ return;
+ }
+
+ $title = $this->getRandomTitle();
+
+ if ( is_null( $title ) ) {
+ $this->setHeaders();
+ // For grep: Uses message randomincategory-nopages
+ $this->getOutput()->addWikiMsg( strtolower(
$this->getName() ) . '-nopages',
+ $this->category->getText() );
+
+ return;
+ }
+
+ $query = $this->getRequest()->getValues();
+ unset( $query['title'] );
+ unset( $query['category'] );
+ $this->getOutput()->redirect( $title->getFullURL( $query ) );
+ }
+
+ /**
+ * Choose a random title.
+ * @return Title object (or null if nothing to choose from)
+ */
+ public function getRandomTitle() {
+ // Convert to float, since we do math with the random number.
+ $rand = floatval( wfRandom() );
+ $title = null;
+
+ // Given that timestamps are rather unevenly distributed, we
also
+ // use an offset between 0 and 30 to make any biases less
noticeable.
+ $offset = mt_rand( 0, $this->maxOffset );
+
+ $row = $this->selectRandomPageFromDB( $rand, $offset );
+
+ // Try again without the timestamp offset (wrap around the end)
+ if ( !$row ) {
+ $row = $this->selectRandomPageFromDB( 0, $offset );
+ }
+
+ // Maybe the category is really small and offset too high
+ if ( !$row ) {
+ $row = $this->selectRandomPageFromDB( $rand, 0 );
+ }
+
+ // Just get the first entry.
+ if ( !$row ) {
+ $row = $this->selectRandomPageFromDB( 0, 0 );
+ }
+
+ if ( $row ) {
+ return Title::makeTitleSafe( $row->page_namespace,
$row->page_title );
+ }
+
+ return null;
+ }
+
+ protected function getQueryInfo( $rand, $offset ) {
+ if ( !$this->category instanceof Title ) {
+ throw new MWException( 'No category set' );
+ }
+ $qi = array(
+ 'tables' => array( 'categorylinks', 'page' ),
+ 'fields' => array( 'page_title', 'page_namespace' ),
+ 'conds' => array_merge( array(
+ 'cl_to' => $this->category->getDBKey(),
+ ), $this->extra ),
+ 'options' => array(
+ 'ORDER BY' => 'cl_timestamp',
+ 'LIMIT' => 1,
+ 'OFFSET' => $offset
+ ),
+ 'join_conds' => array(
+ 'page' => array( 'INNER JOIN', 'cl_from =
page_id' )
+ )
+ );
+ $minClTime = $this->getTimestampOffset( $rand );
+ if ( $minClTime ) {
+ $dbr = wfGetDB( DB_SLAVE );
+ $qi['conds'][] = 'cl_timestamp > ' . $dbr->addQuotes(
$minClTime );
+ }
+ return $qi;
+ }
+
+ /**
+ * @param float $rand Random number between 0 and 1
+ *
+ * @return string|bool A random timestamp from the range of the
category or false on failure
+ */
+ protected function getTimestampOffset( $rand ) {
+ if ( !$this->minTimestamp || !$this->maxTimestamp ) {
+ try {
+ list( $this->minTimestamp, $this->maxTimestamp
) = $this->getMinAndMaxForCat( $this->category );
+ } catch( MWException $e ) {
+ // Possibly no entries in category.
+ return false;
+ }
+ }
+
+ $ts = ( $this->maxTimestamp - $this->minTimestamp ) * $rand +
$this->minTimestamp;
+
+ // XXX: The cl_timestamp field is weird in mysql schema and
uses a different format
+ // than what $dbr->timestamp() yields
+ return wfTimestamp( TS_DB, intval( $ts ) );
+ }
+
+ /**
+ * Get the lowest and highest timestamp for a category.
+ *
+ * @param Title $category
+ * @return Array The lowest and highest timestamp
+ * @throws MWException if category has no entries.
+ */
+ protected function getMinAndMaxForCat( Title $category ) {
+ $dbr = wfGetDB( DB_SLAVE );
+ $res = $dbr->selectRow(
+ 'categorylinks',
+ array(
+ 'MIN( cl_timestamp ) AS low',
+ 'MAX( cl_timestamp ) AS high'
+ ),
+ array(
+ 'cl_to' => $this->category->getDBKey(),
+ ),
+ __METHOD__,
+ array(
+ 'LIMIT' => 1
+ )
+ );
+ if ( !$res ) {
+ throw new MWException( 'No entries in category' );
+ }
+ return array( wfTimestamp( TS_UNIX, $res->low ), wfTimestamp(
TS_UNIX, $res->high ) );
+ }
+
+ /**
+ * @param float $rand A random number that is converted to a random
timestamp
+ * @param int $offset A small offset to make the result seem more
"random"
+ * @param String $fname The name of the calling method
+ * @return Array Info for the title selected.
+ */
+ private function selectRandomPageFromDB( $rand, $offset, $fname =
__METHOD__ ) {
+ $dbr = wfGetDB( DB_SLAVE );
+
+ $query = $this->getQueryInfo( $rand, $offset );
+ $res = $dbr->select(
+ $query['tables'],
+ $query['fields'],
+ $query['conds'],
+ $fname,
+ $query['options'],
+ $query['join_conds']
+ );
+
+ return $dbr->fetchObject( $res );
+ }
+
+ protected function getGroupName() {
+ return 'redirects';
+ }
+}
diff --git a/languages/messages/MessagesEn.php
b/languages/messages/MessagesEn.php
index d675e17..5c51058 100644
--- a/languages/messages/MessagesEn.php
+++ b/languages/messages/MessagesEn.php
@@ -446,6 +446,7 @@
'Protectedpages' => array( 'ProtectedPages' ),
'Protectedtitles' => array( 'ProtectedTitles' ),
'Randompage' => array( 'Random', 'RandomPage' ),
+ 'RandomInCategory' => array( 'RandomInCategory' ),
'Randomredirect' => array( 'RandomRedirect' ),
'Recentchanges' => array( 'RecentChanges' ),
'Recentchangeslinked' => array( 'RecentChangesLinked',
'RelatedChanges' ),
@@ -2602,6 +2603,15 @@
'randompage-nopages' => 'There are no pages in the following
{{PLURAL:$2|namespace|namespaces}}: $1.',
'randompage-url' => 'Special:Random', # do not translate or duplicate this
message to other languages
+# Random page in category
+'randomincategory' => 'Random page in category',
+'randomincategory-invalidcategory' => '"$1" is not a valid category name.',
+'randomincategory-nopages' => 'There are no pages in
[[:Category:$1]].',
+'randomincategory-selectcategory' => 'Get random page from category $1 $2.
+
+<small>The selection process of this page is biased and should not be used for
statistical purposes.</small>',
+'randomincategory-selectcategory-submit' => 'Go',
+
# Random redirect
'randomredirect' => 'Random redirect',
'randomredirect-nopages' => 'There are no redirects in the namespace "$1".',
diff --git a/languages/messages/MessagesQqq.php
b/languages/messages/MessagesQqq.php
index 616ddcd..3daf239 100644
--- a/languages/messages/MessagesQqq.php
+++ b/languages/messages/MessagesQqq.php
@@ -4041,6 +4041,12 @@
'randompage-nopages' => '* $1 - list of namespaces
* $2 - number of namespaces',
+'randomincategory' => '{{doc-special|RandomInCategory}}',
+'randomincategory-invalidcategory' => 'Message shown if an invalid category
is specified. (Note, if the category is simply empty, but could possibly exist,
{{msg-mw|randomincategory-nopages}} is shown instead). $1 is the invalid
category name given.',
+'randomincategory-nopages' => 'Message shown from
Special:RandomInCategory if the category is empty. $1 is the category name
(without the namespace prefix)',
+'randomincategory-selectcategory' => 'Shown on Special:RandomInCategory if
no category is selected. Displays a form allowing the user to input a category
name. $1 is the text field input box, $2 is the go button. The text content of
the button comes from {{msg-mw|randomcategory-selectcategory}}.',
+'randomincategory-selectcategory-submit' => 'Text of button used in
{{msg-mw|randomcategory-selectcategory}}',
+
# Random redirect
'randomredirect' => '{{doc-special|RandomRedirect}}',
'randomredirect-nopages' => '* $1 - namespace name',
diff --git a/maintenance/language/messages.inc
b/maintenance/language/messages.inc
index 2cb94cf..5ac1b63 100644
--- a/maintenance/language/messages.inc
+++ b/maintenance/language/messages.inc
@@ -1664,6 +1664,13 @@
'randompage-nopages',
'randompage-url',
),
+ 'randomincategory' => array(
+ 'randomincategory',
+ 'randomincategory-invalidcategory',
+ 'randomincategory-nopages',
+ 'randomincategory-selectcategory',
+ 'randomincategory-selectcategory-submit',
+ ),
'randomredirect' => array(
'randomredirect',
'randomredirect-nopages',
@@ -4005,6 +4012,7 @@
'listredirects' => 'List redirects',
'unusedtemplates' => 'Unused templates',
'randompage' => 'Random page',
+ 'randomincategory' => 'Special:RandomInCategory,
'randomredirect' => 'Random redirect',
'statistics' => 'Statistics',
'disambiguations' => '',
--
To view, visit https://gerrit.wikimedia.org/r/71997
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I0c48e4a236b50fb627af94f0df47fef8372ea14d
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Brian Wolff <bawolff...@gmail.com>
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