Adds a OOP and declarative parser hook interface on top of MediaWiki

1.4 2014-07-05 20:09 UTC


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OOP interface for creating MediaWiki parser hooks in a declarative fashion.

This is a PHP library for MediaWiki extensions. It does not in itself add or enhance functionality of your wiki.



You can use Composer to download and install this package as well as its dependencies. Alternatively you can simply clone the git repository and take care of loading yourself.


To add this package as a local, per-project dependency to your project, simply add a dependency on mediawiki/parser-hooks to your project's composer.json file. Here is a minimal example of a composer.json file that just defines a dependency on ParserHooks 1.4:

    "require": {
        "mediawiki/parser-hooks": "~1.4"


Get the ParserHooks code, either via git, or some other means. Also get all dependencies. You can find a list of the dependencies in the "require" section of the composer.json file. Load all dependencies and the load the ParserHooks library by including its entry point: ParserHooks.php.


All classes are located in the ParserHooks namespace, which is PSR-0 mapped onto the src/ directory.

General concept

The declarative OOP interface provided by this library allows you to define the signatures of your parser hooks and the handlers for them separately. The library makes use of the parameters specified in this definition to do parameter processing via the ParamProcessor library. This means that the handler you write for your parser function will not need to care about what the name of the parser function is, or how the parameters for it should be processed. It has a "sizes" parameter that takes an array of positive integers? Your handler will always get an actual PHP array of integer without needing to do any parsing, validation, defaulting, etc.


An instance of the HookDefinition class represents the signature of a parser hook. It defines the name of the parser hook and the parameters (including their types, default values, etc) it accepts. It does not define any behaviour, and is thus purely declarative. Instances of this class are used in handling of actual parser hooks, though can also be used in other contexts. For instance, you can feed these definitions to a tool that generates parser hook documentation based on them.

The parameter definitions are ParamProcessor\ParamDefinition objects. See the ParamProcessor documentation on how to specify these.


The actual behaviour for your parser hook is implemented in an implementation of HookHandler. These implementations have a handle method which gets a Parser and a ParamProcssor\ProcessingResult, which is supposed to return a string.

Knitting it all together

This library also provides two additional classes, FunctionRunner, and HookRegistrant. The former takes care of invoking the ParamProcessor library based on a HookDefinition. The later takes care of registering the parser hooks defined by your HookDefinition objects to a MediaWiki Parser object.

$awesomeHookDefinition = new HookDefinition( 'awesome', array( /* ... */ ) );
$anotherHookDefinition = new HookDefinition( 'another', array( /* ... */ ) );

$awesomeHookHandler = new AwesomeHookHandler( /* ... */ );
$anotherHookHandler = new AnotherHookHandler( /* ... */ );

$hookRegistrant = new HookRegistrant( $mediaWikiParser );

$hookRegistrant->registerFunctionHandler( $awesomeHookDefinition, $awesomeHookHandler );
$hookRegistrant->registerFunctionHandler( $anotherHookDefinition, $anotherHookHandler );

If you want to have the same hook, but with other default behaviour, you can avoid any kind of duplication by doing something as follows on top of the above code:

$hookRegistrant->registerFunctionHandler( $extraAwesomeHookDefinition, $awesomeHookHandler );

Where $extraAwesomeHookDefinition is a variation of $awesomeHookDefinition.

Parser functions and tag hooks

To register a parser function, use HookRegistrant::registerFunctionHandler.

$hookRegistrant->registerFunctionHandler( $awesomeHookDefinition, $awesomeHookHandler );

To register a tag hook, use HookRegistrant::registerHookHandler.

$hookRegistrant->registerHookHandler( $awesomeHookDefinition, $awesomeHookHandler );

Both functions take the exact same arguments, so once you created a HookDefinition and a HookHandler, you can have them registered as both parser function and tag hook with no extra work.


This library comes with a set up PHPUnit tests that cover all non-trivial code. You can run these tests using the PHPUnit configuration file found in the root directory. The tests can also be run via TravisCI, as a TravisCI configuration file is also provided in the root directory.

The tests can be run for the tests/phpunit directory of your MediaWiki installation with this command:

php phpunit.php -c ../../extensions/ParserHooks/


ParserHooks has been written by Jeroen De Dauw as a hobby project to support the SubPageList MediaWiki extension.

Release notes

1.4 (2014-07-05)

  • Changed the PHPUnit bootstrap so that the tests can be run via the MediaWiki test runner
  • Updated the CI configuration to test the code against multiple MediaWiki versions

1.3 (2014-06-25)

  • Updated i18n message files
  • Changed class loading to PSR-4
  • Updated the used Validator version to 2.x >= 2.0.4

1.2.1 (2013-11-22)

  • Updated the used Validator version from 1.0 alpha to stable, or later

1.2 (2013-09-30)

  • Fixed parameter handling bug in FunctionRunner
  • Added system test for tag hook handling

1.1 (2013-09-25)

  • Added HookRunner and HookRegistrant::registerHook
  • Added HookRegistrant::registerFunctionHandler and HookRegistrant::registerHookHandler
  • Fixed parameter handling bug in FunctionRunner
  • Improved HookRegistrantTest

You can read the release blog post

1.0.1 (2013-09-22)

  • Improved HookDefinition documentation
  • Added extra type checking in HookDefinition
  • Added extra tests for HookDefinition
  • Added support
  • Added PHPUnit file whitelisting (for more accurate and faster generated coverage reports)

1.0 (2013-07-14)