Manual:Hooks/MessageCacheFetchOverrides

MessageCacheFetchOverrides
Available from version 1.41.0 (Gerrit change 884416) Allows changing message keys to customize them before the translation is accessed
Define function:	public static function onMessageCacheFetchOverrides( array &$keys ) { ... }
Attach hook:	In extension.json: { "Hooks": { "MessageCacheFetchOverrides": "MediaWiki\\Extension\\MyExtension\\Hooks::onMessageCacheFetchOverrides" } }
Called from:	File(s): Language/MessageCache.php
Interface:	MessageCacheFetchOverridesHook.php

For more information about attaching hooks, see Manual:Hooks .
For examples of extensions using this hook, see Category:MessageCacheFetchOverrides extensions.

Details

Both the input and output keys must have an initial lowercase character. No spaces can be used in the keys; any spaces must be converted to underscores.

• &$keys - Array of message keys mapped to their replacement.

Values may be either a string or a callable that returns a string. Callables are provided two arguments: the message key, an instance of MessageCache. Before MediaWiki 1.44, there were two extra arguments: a Language object, and a boolean indicating if the value should be loaded from the database.

// Since MediaWiki 1.44
function ( string $key, MessageCache $cache ): string { ... }
// Previous versions
function ( string $key, MessageCache $cache, Language $language, bool $useDB ): string { ... }

To prevent ambiguity between message keys that can also be interpreted as a callable (strtotime, for example), all string values are interpreted as a message key. To use a callable defined as a string, use Closure::fromCallable.

See also

• MessagesPreLoad hook
• MessageCache::get hook