ReaderExperiments

A set of prototypes that aim at growing Wikipedia readers.

• Prototypes are temporary, disposable, and not optimized
• Decoupled architecture for fast development: back-end PHP API endpoints deliver JSON over HTTP to front-end JavaScript & CSS applications
• API endpoints are stubs and can be tailored for a single feature
• User interfaces in Vue.js and Codex. The HTML output or cache is left untouched if possible
• One-time shared setup for metrics integration, user preferences, etc.

• Install MediaWiki through the local development quickstart
• Clone these repositories:

USERNAME=  # Fill in your shell user name here
git clone ssh://${USERNAME}@gerrit.wikimedia.org:29418/mediawiki/skins/MinervaNeue skins/MinervaNeue
for extension in MobileFrontend MobileFrontendContentProvider MultimediaViewer ReaderExperiments; do
    git clone "ssh://${USERNAME}@gerrit.wikimedia.org:29418/mediawiki/extensions/${extension}" "extensions/${extension}"
done

• Add the following to LocalSettings.php:

wfLoadExtensions( [
    'MobileFrontend',
    'MobileFrontendContentProvider',
    'MultimediaViewer',
    'ReaderExperiments'
] );

wfLoadSkin( 'MinervaNeue' );
$wgDefaultMobileSkin = 'minerva';

$wgLanguageCode = "en";  # You can set another language here
$wgMFMwApiContentProviderBaseUri = "https://$wgLanguageCode.wikipedia.org/w/api.php";
$wgReaderExperimentsApiBaseUri = $wgMFMwApiContentProviderBaseUri;
$wgGenerateThumbnailOnParse = false;

Consider using Fresh to handle Node.js and/or npm.

This feature can be enabled in two ways:

1. URL parameter (for testing) - append ?imageBrowsing=1 to any article URL
2. Experiment assignment - users assigned to the treatment group via ExperimentManager

Example with URL parameter: /wiki/Angkor_Wat?imageBrowsing=1

Notes:

• The URL parameter bypasses experiment gating for easy testing
• Without the URL parameter, the feature only loads for users in the experiment treatment group

The following instructions apply to the local development quickstart.

cd extensions/ReaderExperiments
composer update
composer fix  # Auto-fix PHP
composer test

cd extensions/ReaderExperiments
npm ci
npm run fix  # Auto-fix JavaScript
npm run lint

composer phpunit:entrypoint -- extensions/ReaderExperiments/tests/phpunit/

cd extensions/ReaderExperiments
npm ci
npm run jest

This recipe sets up a full environment to develop instruments.

• Clone these repositories:

for extension in EventBus EventLogging EventStreamConfig TestKitchen WikimediaEvents; do
    git clone "https://gerrit.wikimedia.org/r/mediawiki/extensions/${extension}" "extensions/${extension}"
done

• Install EventLogging dependencies:

cd extensions/EventLogging
composer update

• Add the following to LocalSettings.php:

# https://www.mediawiki.org/wiki/MediaWiki-Docker/Configuration_recipes/EventLogging#Event_Platform
wfLoadExtensions( [
	'EventBus',
	'EventLogging',
	'EventStreamConfig',
	'TestKitchen',
	'WikimediaEvents'
] );

# EventBus
$wgEventServices = [
	'*' => [ 'url' => 'http://eventlogging:8192/v1/events' ],
];
$wgEventServiceDefault = '*';
$wgEnableEventBus = 'TYPE_EVENT';

# EventLogging
# https://github.com/wikimedia/mediawiki-extensions-EventLogging/blob/master/devserver/README.md
$wgEventLoggingServiceUri = 'http://localhost:8192/v1/events';
$wgEventLoggingBaseUri = '/beacon/event';
# Wait 1 second before sending batches of queued events
$wgEventLoggingQueueLingerSeconds = 1;
# Disable events when running PHP tests
if ( defined( 'MW_PHPUNIT_TEST' ) ) {
	$wgEnableEventBus = 'TYPE_NONE';
	$wgEventLoggingServiceUri = false;
}

# Test Kitchen (FKA xLab)
# https://wikitech.wikimedia.org/wiki/Test_Kitchen/Local_development_setup#Install_TestKitchen_extension
$wgTestKitchenEnable = true;
$wgTestKitchenEnableExperiments = true;
$wgTestKitchenEnableExperimentOverrides = true;

$wgEventStreams = [
	// Add custom streams here.
];
$wgTestKitchenExperimentStreamNames = array_keys( $wgEventStreams );

• Spin up the events server:

cd extensions/EventLogging/devserver
npm install --omit=optional
npm run eventgate-devserver

• Open another terminal window, cd to devserver and tail -f events.json
• Load a page like http://localhost:4000/index.php/Eddie_Cochran
• In the browser console, fire a test event:

mw.eventLog.submit(
  'foo',
  {
    $schema: '/analytics/product_metrics/web/base/2.1.0',
    action: 'test'
  }
);

• You should see the event JSON in events.json

A/B tests live in the Test_Kitchen (FKA xLab) as experiments.

There are 3 layers where you can test an experiment:

1. Local development environment - set up instrumentation, then use the HTTP headers method
2. Beta cluster - override enrollment
3. Production - override enrollment