Extension:Cognate

MediaWiki extensions manual

Cognate Release status: stable
Implementation	Database
Description	Link different language versions of a page by using the page title.
Author(s)	Gabriel Birke, Addshore
Latest version	Continuous updates
Compatibility policy	Snapshots releases along with MediaWiki. Master is not backward compatible.
MediaWiki	1.29+
Database changes	Yes
Tables	cognate_sites cognate_pages cognate_titles
License	GNU General Public License 2.0 or later
Download	Download extension Git [?]: Download Git master browse repository (GitHub) commit history repository contributors (GitHub) code review
Parameters $wgCognateNamespaces $wgCognateReadOnly
Hooks used ArticleUndelete ContentAlterParserOutput LoadExtensionSchemaUpdates PageMoveComplete PageSaveComplete WikiPageDeletionUpdates
Quarterly downloads	1 (Ranked 128th)
Translate the Cognate extension if it is available at translatewiki.net
Issues	Open tasks · Report a bug

The Cognate extension creates a central store where the page titles for a group of sites are stored. It can then generate interwiki links across wiki projects in cases where the titles are the same. It was developed to solve the "Centralize interwiki language links for Wiktionary" task.

"Cognate" is a linguistic concept, referring to words in different languages developed from the same origin. This means that this extension is misnamed—since this extension links pages with the same title across wikis, a proper name would be “Homograph”.

Assumptions and restrictions

• Pages must be in one of the standard MediaWiki namespaces.
• Page titles are the same across languages (with some simple normalization applied).
• Sites should have the same interwiki structure for language links.
• Pages should not contain inter language links in wikitext as these will override the link provided by Cognate.
• Unexpected hash conflicts are unlikely but could occur, and would result in unexpected language links.

How it works

Title Normalization

Very simple title normalization (reduction to ASCII) occurs within the extension. This can be seen in the StringNormalizer class.

Initially the amount of normalization is very small. Requests can be made to expand this and will be added on a case by case basis.

String	Normalized	Notes
Hello…	Hello...	The raw string contains an ellipsis character. This is normalized to three . characters
lepelle’	lepelle'	The normalized string has a normalized apostrophe.

Title Hashing

Titles are hashed using sha256. This can be seen in the StringHasher class.

Part of the hash is then stored in the database in a BIG_INT field for efficient lookups.

There are roughly 18,446,744,073,709,551,615 possible values.

String	Hash	Int
A	559AEAD08264D5795D3909718CDD05ABD49572E84FE55590EEF31A88A08FDFFD	6168500820899059065
Foo	1CBEC737F863E4922CEE63CC2EBBFAAFCD1CFF8B790D8CFD2E6A5D550B648AFA	2071311921841431698
1234567890	C775E7B757EDE630CD0AA1113BD102661AB38829CA52A6422AB782862F268646	-4074095513246505424

Matching Hashes

As titles that require links are assumed to be the same post normalization, they will result in the same hash and thus the same Int stored in the database.

Some sample data might look as follows when loading the "Foo..." page on enwiktionary.

Wiki	Title	Hash Int	Normalized Hash Int	Notes
enwiktionary	Foo...	395730596998145766	395730596998145766	Matched row
frwiktionary	Foo…	-7435652355441782233	395730596998145766	Matched row, even though the pre normalized title includes the ellipsis character.
dewiktionary	Foo...	395730596998145766	395730596998145766	Matched row
arwiktionary	Foo	2071311921841431698	2071311921841431698

Overwriting

It is possible to overwrite the automatic links provided by Cognate, simply by adding one or more interwiki links in the page.

That also means that to make Cognate work when the extension is deployed, the pages should not contain inter language links in their wikitext.

Testing

The extension can be tested on beta wiktionary sites:

• https://en.wiktionary.beta.wmflabs.org/wiki/Wiktionary:Main_Page
• https://de.wiktionary.beta.wmflabs.org/wiki/Hauptseite
• https://he.wiktionary.beta.wmflabs.org/wiki/%D7%A2%D7%9E%D7%95%D7%93_%D7%A8%D7%90%D7%A9%D7%99

These sites are linked together using the Cognate extension with added interwiki sorting provided by the InterwikiSorting extension.

Installation

• Download and move the extracted Cognate folder to your extensions/ directory.
  Developers and code contributors should install the extension from Git instead, using:cd extensions/
git clone https://gerrit.wikimedia.org/r/mediawiki/extensions/Cognate
• Add the following code at the bottom of your LocalSettings.php file:

  wfLoadExtension( 'Cognate' );
  # Settings used in WMF production
  # Use the external cluster 'extension1' and dbname 'cognate_wiktionary'
  $wgCognateDb = 'cognate_wiktionary';
  $wgCognateCluster = 'extension1';
  # Only work on the main namespace
  $wgCognateNamespaces = [ 0 ];
  

• Run the update script which will automatically create the necessary database tables that this extension needs.
•  Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.

• Populate the sites table by running the populateCognateSites.php maintenance script. Sites must already exist in the MediaWiki sites table with the correct groupings.

php ./maintenance/populateCognateSites.php --site-group=wiktionary

• Populate the page and title tables by running the populateCognatePages.php maintenance script.

php ./maintenance/populateCognatePages.php