Topic on Project:Support desk

I was looking at the ParserFirstCallInit hook, and I think it is confusing, unless someone can explain the notation. I see something like this:

function fnMyHook( &$parser ) {
    ...
}
$wgHooks['ParserFirstCallInit'][] = 'MyExtensionHooks::someExample';

Shouldn't the second line be:

$wgHooks['ParserFirstCallInit'][] = 'fnMyHook';

I really don't understand how they tie together if I use someExample. Wouldn't I also have to define someExample and have it use the same function arguments and call fnMyHook?

Thanks.

No, you shouldn't create a global function for each hook. The "right way" (anno 2012) would be to have a *.hooks.php file in your extension folder, in which you create a class with public static methods. Then in your main extension php file:

$wgAutoloadClasses['VectorHooks'] = dirname( __FILE__ ) . '/Vector.hooks.php';

$wgHooks['GetPreferences'][] = 'VectorHooks::getPreferences';
$wgHooks['BeforePageDisplay'][] = 'VectorHooks::beforePageDisplay';

Look at the files in mediawiki/extensions/Vector.git as example.

Basically the IP who asks the question is right: The definition inside the "$wgHooks['ParserFirstCallInit'][] = " line must fit to the function name. In the example, this should also be the case, but is not.

Either the second line should be

$wgHooks['ParserFirstCallInit'][] = 'fnMyHook';

or the hook function should be

class MyExtensionHooks {
 function someExample() {
 // ...your code...
 return true;
 }
}

Fixed: See Manual:Hooks/ParserFirstCallInit

The function sample now matches what it should be (a public static function, with the same name as the value added to the $wgHooks registry).

Thanks for the fix! I also tried that but did not really step through how all these templates relate to each other. :-)

I encountered this yesterday on another hook page and was quite confused by what the sample code was indicating: http://www.mediawiki.org/wiki/Manual:Hooks/ImageBeforeProduceHTML

It looks like all your hooks examples are done this way.

You mean the class name, which is present in the line "$wgHooks['ParserFirstCallInit'][] = ...", but not present in the function definition? Right, it should be at both places, or at none. Having it at both would blow up all the function definitions, so I have just taken it out.

Reverted, please discuss further at Template talk:MediaWikiHook.