Introduced $wgULSAnonCanChangeLanguage

This allows us to enable web fonts and input methods for all
users by disabling just the interface language selection.

Updated the documentation of the variables to make it clearer
what each does. Summary:
* Enabling: $wgULSEnable and $wgULSEnableAnon
* Workarounds: $wgULSAnonCanChangeLanguage and $wgULSLanguageDetection

Cleaned up hooks, in particular rewritten getLanguage to separate
the logged in vs. logged out steps for easier understanding.

A followup commit is needed to disable language selection UI for
anon if $wgULSAnonCanChangeLanguage is false.

Change-Id: Ia8d21c394ff5efac0ce94664710c97dc3b74ec18

UniversalLanguageSelector.hooks.php

@@ -19,15 +19,17 @@
  */
 
 class UniversalLanguageSelectorHooks {
+	/**
+	 * Whether ULS user toolbar (language selection and settings) is enabled.
+	 * @return bool
+	 */
 	public static function isToolbarEnabled( $user ) {
 		global $wgULSEnable, $wgULSEnableAnon;
 		if ( !$wgULSEnable ) {
 			return false;
 		}
-		if ( !$wgULSEnableAnon ) {
-			if ( $user->isAnon() ) {
-				return false;
-			}
+		if ( !$wgULSEnableAnon && $user->isAnon() ) {
+			return false;
 		}
 		return true;
 	}
@@ -141,7 +143,7 @@ class UniversalLanguageSelectorHooks {
 	 * @return bool
 	 */
 	public static function getLanguage( $user, &$code, $context = null ) {
-		global $wgUser, $wgRequest, $wgULSLanguageDetection;
+		global $wgUser, $wgRequest, $wgULSAnonCanChangeLanguage, $wgULSLanguageDetection;
 		if ( !self::isToolbarEnabled( $user ) ) {
 			return true;
 		}
@@ -167,27 +169,40 @@ class UniversalLanguageSelectorHooks {
 			return true;
 		}
 
-		$languageToUse = null;
-		if ( self::isSupportedLanguage( $languageToSave ) ) {
-			if ( $user->isAnon() ) {
-				$request->response()->setcookie( 'language', $languageToSave );
-			} else {
+		// Registered users - simple
+		if ( !$user->isAnon() ) {
+			// Language change
+			if ( self::isSupportedLanguage( $languageToSave ) ) {
 				$user->setOption( 'language', $languageToSave );
 				$user->saveSettings();
+				// Apply immediately
+				$code = $languageToSave;
 			}
-			$languageToUse = $languageToSave;
+			// Otherwise just use what is stored in preferences
+			return true;
 		}
 
-		// Load from cookie unless overriden
-		if ( $languageToUse === null && $user->isAnon() ) {
-			$languageToUse = $request->getCookie( 'language' );
+		// Logged out users - less simple
+		if ( !$wgULSAnonCanChangeLanguage ) {
+			return true;
 		}
 
-		// Check whether we got valid language from store or
-		// explicit language change.
+		// Language change
+		if ( self::isSupportedLanguage( $languageToSave ) ) {
+			$request->response()->setcookie( 'language', $languageToSave );
+			$code = $languageToSave;
+			return true;
+		}
+
+		// Try cookie
+		$languageToUse = $request->getCookie( 'language' );
 		if ( self::isSupportedLanguage( $languageToUse ) ) {
 			$code = $languageToUse;
-		} elseif ( $user->isAnon() && $wgULSLanguageDetection ) {
+			return true;
+		}
+
+		// As last resort, try Accept-Language headers if allowed
+		if ( $wgULSLanguageDetection ) {
 			$preferred = $request->getAcceptLang();
 			$default = self::getDefaultLanguage( $preferred );
 			if ( $default !== '' ) {
@@ -195,7 +210,7 @@ class UniversalLanguageSelectorHooks {
 			}
 		}
 
-		// Fall back to content language
+		// Fall back to other hooks or content language
 		return true;
 	}
 
@@ -205,10 +220,14 @@ class UniversalLanguageSelectorHooks {
 	 * @return bool
 	 */
 	public static function addConfig( &$vars ) {
-		global $wgULSGeoService, $wgULSIMEEnabled;
-		$vars['wgULSGeoService'] = $wgULSGeoService;
+		global $wgULSGeoService, $wgULSIMEEnabled, $wgULSPosition,
+			$wgULSAnonCanChangeLanguage;
 
+		// Place constant stuff here (not depending on request context)
+		$vars['wgULSGeoService'] = $wgULSGeoService;
 		$vars['wgULSIMEEnabled'] = $wgULSIMEEnabled;
+		$vars['wgULSPosition'] = $wgULSPosition;
+		$vars['wgULSAnonCanChangeLanguage'] = $wgULSAnonCanChangeLanguage;
 
 		// ULS is localized using jquery.i18n library. Unless it knows
 		// the localized locales, it can create 404 response. To avoid that,
@@ -253,12 +272,11 @@ class UniversalLanguageSelectorHooks {
 	 * @return bool
 	 */
 	public static function addVariables( &$vars, OutputPage $out ) {
+		// Place request context dependent stuff here
 		$vars['wgULSLanguages'] = Language::fetchLanguageNames(
 			$out->getLanguage()->getCode(), 'mwfile'
 		);
 		$vars['wgULSAcceptLanguageList'] = array_keys( $out->getRequest()->getAcceptLang() );
-		global $wgULSPosition;
-		$vars['wgULSPosition'] = $wgULSPosition;
 
 		return true;
 	}
@@ -284,6 +302,10 @@ class UniversalLanguageSelectorHooks {
 			return true;
 		}
 
+		if ( !self::isToolbarEnabled( $skin->getUser() ) ) {
+			return true;
+		}
+
 		// A dummy link, just to make sure that the section appears
 		$template->data['language_urls'][] = array(
 			'href' => '#',

UniversalLanguageSelector.php

@@ -25,7 +25,7 @@ if ( !defined( 'MEDIAWIKI' ) ) {
 /**
  * Version number used in extension credits and in other placed where needed.
  */
-define( 'ULS_VERSION', '2013-04-01' );
+define( 'ULS_VERSION', '2013-04-27' );
 
 $wgExtensionCredits['other'][] = array(
 	'path' => __FILE__,
@@ -57,32 +57,53 @@ $wgExtensionCredits['other'][] = array(
 $wgULSGeoService = 'http://freegeoip.net/json/';
 
 /**
- * IME system of ULS can be disabled by setting this value false;
- */
-$wgULSIMEEnabled = true;
-
-/**
- * Try to use preferred interface language for anonymous users.
- * Do not use if you are caching anonymous page views without
- * taking Accept-Language into account.
- */
-$wgULSLanguageDetection = true;
-
-/**
- * Enable language selection. If language selection is disabled, the classes
- * and RL modules are registered for the use of other extensions, but no
- * language selection toolbar is shown, and it will not be possible to change
- * the interface language using a cookie.
+ * Enable language selection, input methods and webfonts for everyone, unless
+ * the behavior is overridden by the configuration variables below.
+ *
+ * Even if false the classes and resource loader modules are registered for the
+ * use of other extensions. Language changing via cookie or setlang query
+ * parameter is not possible.
  */
 $wgULSEnable = true;
 
 /**
- * Enable ULS language selection for anonymous users. Equivalent to $wgULSEnable
- * except that it only applies to anonymous users. Setting this to false will
- * avoid breaking Squid caches (see bug 41451).
+ * Equivalent to $wgULSEnable for anonymous users only.
+ *
+ * Does not have any effect if $wgULSEnable is false.
  */
 $wgULSEnableAnon = true;
 
+/**
+ * Allow anonymous users to change language with cookie and setlang
+ * query param.
+
+ * Do not use if you are caching anonymous page views without
+ * taking cookies into account.
+ *
+ * Does not have any effect if either of $wgULSEnable or
+ * $wgULSEnableAnon is set to false.
+ *
+ * @since 2013.04
+ */
+$wgULSAnonCanChangeLanguage = true;
+
+/**
+ * Try to use preferred interface language for anonymous users.
+ *
+ * Do not use if you are caching anonymous page views without
+ * taking Accept-Language into account.
+ *
+ * Does not have any effect if any of $wgULSEnable, $wgULSEnableAnon
+ * or $wgULSAnonCanChangeLanguage is set to false.
+ */
+$wgULSLanguageDetection = true;
+
+/**
+ * Disable the input methods feature for all users by default. Can still
+ * be enabled manually by the user.
+ */
+$wgULSIMEEnabled = true;
+
 /**
  * The location and the form of the language selection trigger.
  * The possible values are: