ottomata / mediawiki-extensions-ConfigExports

PoC repo for development of Config Service for Wikimedia Event Stream Config

ConfigExports MediaWiki Extension

Exports whitelisted MediaWiki configs via ResourceLoader into mw.config and via a MediaWiki action API endpoint.

Configuration

The minimal configuration must provide the whitelist of MediaWiki Config names to allow exporting. This extension does not allow auto export of all MediaWiki config. Configs must be explicitly whitelisted here.

/** @var array list of MediaWiki config keys (for use with $config->getConfig())
 *             to allow this extension to expose.
 */
$wgConfigExportsKeysWhitelist = [
    'EventServiceStreamConfig',
    'OtherMWConfigKey',
    // ...
];

Config Selection

Both the API endpoint and the ResourceLoader hook allow for selection of specific configs in the same way. The API endpoint specifies target configs using the configs API query parameter, while ResourceLoader allows target configs to both be specified in MediaWiki Config itself and by other extension's attributes. (More on this below.)

Configs may be be selected by top level MediaWiki Config name:

• API: ?configs=MWConfigKey1|MWConfigKey2
• Extension Attributes: ["MWConfigKey1", "MWConfigKey2"]

If the target MediaWiki config value is an object, fields to return can be filtered by key:

• API: ?configs=MWConfigKey1.subkey1|MWConfigKey2.subkey2
• Extension Attributes: ["MWConfigKey1.subkey1", "MWConfigKey2.subkey2"]

Sub-key filtering is done using PHPs fnmatch, so glob pattern matching is supported:

• API: ?configs=MWConfigKey1.sub-key-pattern-*
• Extension Attributes: ["MWConfigKey1.sub-key-pattern-*]

Note that sub key filtering is only supported at the top level keys of any given config object. You cannot use globs to match across MediaWiki config names, and you cannot match sub-sub keys of config objects.

API Endpoint

Get all whitelisted MediaWiki configs in $wgConfigExportsKeysWhitelist

GET /w/api.php?action=config_exports&format=json

Get specified MediaWiki configs. Only MediaWiki config names listed in $wgConfigExportsKeysWhitelist will be allowed to be exported. Requesting non whitelisted config names will result in an error.

GET /w/api.php?action=config_exports&format=json&configs=EventServiceStreamConfig|OtherMWConfigKey.subkey*

ResourceLoader

This ConfigExports extension registers a MakeGlobalVariablesScript that sets configs in mw.config based on the MediaWiki Config $wgConfigExportsKeys, as well as config keys listed in any registered extension attributes ConfigExportsKeys.

$wgConfigExportsKeys allows for global configuration of keys that should always be exported by ResourceLoader.

Other extensions may register keys they'd like to export in attributes in their extention.json file:

"attributes": {
    "ConfigExports": {
        "Keys": ["EventServiceStreamConfig.page-edit-*", "AnotherMWConfigKey"]
    }
}

The final list of config keys to export will be the union of $wgConfigExportsKeys with all loaded extensions' ConfigExportKeys attribute.

Once the page is loaded, ResourceLoader will make all exported configs available in mw.config:

var streamConfig = mw.config.get('EventServiceStreamConfig');