Avoid 404s in non-localized locales

* Update jquery.i18n - if messageLocationResolver returns false for
  a locale, no server hit will be attempted
* Refactor i18n preparation code to a new method
* Use the ULS RL hooks to find out to which locales it is localized,
  pass that list to js to avoid hitting server.
* Also avoid directory scanning in each request by putting
  the locale list in cache

Fixes Bug 41454

Change-Id: I0c923b35db01b884e2dd55873dd5fb7384434645

UniversalLanguageSelector.hooks.php

@@ -165,6 +165,39 @@ class UniversalLanguageSelectorHooks {
 		global $wgULSGeoService;
 		$vars['wgULSGeoService'] = $wgULSGeoService;
 
+		// ULS is localized using jquery.i18n library. Unless it knows
+		// the localized locales, it can create 404 response. To avoid that,
+		// send the locales available at server. Also avoid directory scanning
+		// in each request by putting the locale list in cache.
+		$cache = wfGetCache( CACHE_ANYTHING );
+		$key = wfMemcKey( 'uls', 'i18n', 'locales' );
+		$result = $cache->get( $key );
+
+		if ( $result ) {
+			$vars['wgULSi18nLocales'] = $result;
+		} else {
+			$mwULSL10nFiles = glob( __DIR__ . '/i18n/*.json' );
+
+			foreach ( $mwULSL10nFiles as $localeFile ) {
+				$mwULSL10nLocales[] = basename( $localeFile, '.json' );
+			}
+
+			$mwULSL10nFiles = glob( __DIR__ . '/lib/jquery.uls/i18n/*.json' );
+
+			foreach ( $mwULSL10nFiles as $localeFile ) {
+				$jqueryULSL10nLocales[] = basename( $localeFile, '.json' );
+			}
+
+			$vars['wgULSi18nLocales'] = array(
+				// Locales to which jQuery ULS is localized.
+				'uls' => $jqueryULSL10nLocales,
+				// Locales to which Mediawiki ULS is localized.
+				'ext-uls' => $mwULSL10nLocales,
+			);
+
+			// Cache it for 1 hour
+			$cache->set( $key, $vars['wgULSi18nLocales'], 3600 );
+		}
 		return true;
 	}
 

lib/jquery.i18n.js

@@ -49,7 +49,7 @@
 
 			// Override String.localeString method
 			String.prototype.toLocaleString = function () {
-				var localeParts, localePartIndex, value, locale, fallbackIndex;
+				var localeParts, messages, localePartIndex, value, locale, fallbackIndex;
 
 				value = this.valueOf();
 				locale = i18n.locale;
@@ -65,12 +65,11 @@
 						var _locale = localeParts.slice( 0, localePartIndex ).join( "-" );
 
 						if ( !i18n.messageStore.messages[_locale]  && i18n.options.messageLocationResolver ) {
-							// FIXME If messageloading gives 404, it keep on trying to
+							messages = i18n.options.messageLocationResolver( _locale, value );
-							// load the file again and again
+
-							i18n.messageStore.load(
+							if ( messages ) {
-									i18n.options.messageLocationResolver( _locale ),
+								i18n.messageStore.load( messages, _locale );
-									_locale
+							}
-								);
 						}
 
 						var message = i18n.messageStore.get( _locale, value );

resources/js/ext.uls.init.js

@@ -90,26 +90,49 @@
 		return unique;
 	};
 
-	$( document ).ready( function () {
+	/**
-		var extensionPath, i18n, $ulsTrigger, previousLanguages, previousLang;
+	 * i18n initialization
+	 */
+	function i18nInit () {
+		var extensionPath, locales, i18n;
 
 		extensionPath = mw.config.get( 'wgExtensionAssetsPath' )
-			+ '/UniversalLanguageSelector/';
+		+ '/UniversalLanguageSelector/';
-		// i18n initialization
+
+		locales = mw.config.get( 'wgULSi18nLocales' );
 		i18n = $.i18n( {
 			locale: currentLang,
-			messageLocationResolver: function ( locale ) {
+			messageLocationResolver: function ( locale, messageKey ) {
-				return extensionPath + 'i18n/' + locale + '.json';
+				// Namespaces are not available in jquery.i18n yet. Developers prefix
+				// the message key with a unique namespace like ext-uls-*
+
+				if ( messageKey.indexOf( 'uls' ) === 0 ) {
+					if ( $.inArray( locale, locales['uls'] ) >= 0 ) {
+						return extensionPath + 'lib/jquery.uls/i18n/' + locale + '.json';
+					}
+
+					return false;
+				}
+
+				if ( messageKey.indexOf( 'ext-uls' ) === 0 ) {
+					if ( $.inArray( locale, locales['ext-uls'] ) >= 0 ) {
+						return extensionPath + 'i18n/' + locale + '.json';
+					}
+
+					return false;
+				}
 			}
 		} );
-		// localization for jquery.uls
+
-		i18n.load( extensionPath + 'lib/jquery.uls/i18n/' + currentLang + '.json', currentLang );
+		// localization for mediaWiki ULS - fallback locale
-		// localization for jquery.uls- fallback locale
-		i18n.load( extensionPath + 'lib/jquery.uls/i18n/en.json', 'en' );
-		// localization for mediaWiki ULS
-		i18n.load( extensionPath + 'i18n/' + currentLang + '.json', currentLang );
-		// localization for mediaWiki ULS- fallback locale
 		i18n.load( extensionPath + 'i18n/en.json', 'en'  );
+	}
+
+	$( document ).ready( function () {
+		var $ulsTrigger, previousLanguages, previousLang;
+
+		// JavaScript side i18n initialization
+		i18nInit();
 
 		$ulsTrigger = $( '.uls-trigger' );
 		previousLanguages = mw.uls.getPreviousLanguages() || [];