README

MediaWiki extension that adds support for the Extended Date/Time Format (EDTF) Specification to Wikibase via a new data type.

Professional Wiki created and maintains Wikibase EDTF. We provide Wikibase hosting, Wikibase development, and Wikibase consulting.

Wikibase EDTF is an open-source project that was made possible with the financial support of the Luxembourg Ministry of Culture. Contributions are welcome!

You can find a demo of this extension at https://edtf.wikibase.wiki

• Usage
  • RDF export
• Installation
• Running the tests
• Release notes

Usage

RDF export

Wikibase EDTF gives its value to the native RDF export mechanism using the datatypes xsd:EDTF datatype (e.g. "1867-05-26"^^xsd:edtf) and xsd:dateTime. For the latter datatype it turns EDTF values into standard Wikibase time (xsd:dateTime) values. Because Wikibase time values are a lot less expressive, the EDTF values are simplified in this process:

• EDTF date or time: Precision and time zone are retained. Qualifications and unspecified digits are discarded.
• EDTF Set: Each date in the set is exported.
• EDTF Season: One date for each month is exported, each having month precision.
• EDTF Interval: Nothing is exported (since there does not seem to be a reasonable default).

For cases where multiple dates are put in the RDF export, like with seasons and sets, there is nothing in the RDF indicating these values logically belong together.

If you can read PHP, you can see the simplification code in TimeValueBuilder.php.

Apparent duplicate results using SPARQL / Blazegraph

Because EDTF exposes the values as both xsd:edtf and a dumbed down xsd:dateTime you will get two values when querying properties with this datatype. using a filter in your SPARQL query can remove the value that you are not interested in:

FILTER ( datatype(?date) = xsd:edtf ) #shows only the raw EDTF string from the query results, in this case ?date

FILTER ( datatype(?date) = xsd:dateTime ) #shows only the dumbed down EDTF strings from the query results, in this case ?date

note that if you are using OPTIONAL on the property, then you need to move the FILTER within the OPTIONAL statement.

Installation

Platform requirements for the latest version:

• PHP 7.4 or later, including PHP 8.x, tested up to PHP 8.4
• MediaWiki 1.40 up to 1.44
• Wikibase Repository compatible with your MediaWiki version

See the release notes for more information on the different versions of this extension.

The recommended way to install Wikibase EDTF is using Composer with MediaWiki's built-in support for Composer.

On the commandline, go to your wiki's root directory. Then run these two commands:

COMPOSER=composer.local.json composer require --no-update professional-wiki/wikibase-edtf:^3.0.0

If you have MediaWiki 1.39, 1.38, or 1.37, use ^2.0.0. If you have MediaWiki 1.36 or earlier, use ^1.2.0.

composer update professional-wiki/wikibase-edtf --no-dev -o

Enabling the extension

Then enable the extension by adding the following to the bottom of your wiki's "LocalSettings.php" file:

wfLoadExtension( 'WikibaseEdtf' );

You can verify the extension was enabled successfully by opening your wiki's "Special:Version" page in your browser.

Running the tests

• PHP tests: php tests/phpunit/phpunit.php -c extensions/WikibaseEdtf/

Release notes

Version 3.0.0 - 2025-07-10

• Raised minimum MediaWiki and Wikibase versions from 1.37 to 1.40
• Added support for MediaWiki and Wikibase 1.44

Version 2.1.2 - 2025-07-08

• Added support for MediaWiki and Wikibase 1.40, 1.41, 1.42, and 1.43
• Translation updates

Version 2.1.1 - 2023-03-31

• Added support for MediaWiki and Wikibase 1.38 and 1.39
• Translation updates

Version 2.1.0 - 2023-01-18

• Added support for EDTF 3.x, which brings improved humanizations
• Translation updates

Version 2.0.1 - 2022-03-26

• Added missing messages for Special:ListDatatypes

Version 2.0.0 - 2022-01-23

• Added support for MediaWiki and Wikibase 1.37
• Raised minimum MediaWiki and Wikibase versions to 1.37

Version 1.2.0 - 2021-04-28

• Improved humanization of sets
• Improved validation of intervals and sets
• Fixed DoS vector

Version 1.1.0 - 2021-04-04

• Added plain EDTF value to RDF output

Version 1.0.0 - 2021-03-19

• Initial release for MediaWiki/Wikibase 1.35 (Release announcement, Demo video)
• EDTF datatype with
  • Support for EDTF levels 0, 1 and 2
  • Input validation
  • Display of humanized and internationalized version in the reading UI
  • RDF export (using standard Wikibase dates) for most values