Enable URL lang parameter for switching languages (fixes #1080)

.gitignore

@@ -12,3 +12,4 @@ bin
 perfstats*.csv
 coverage.xml
 !gui/scripts/syncthing
+.DS_Store

gui/scripts/syncthing/core/controllers/syncthingController.js

@@ -918,11 +918,12 @@ angular.module('syncthing.core')
                 var devices = $scope.folders[folderID].Devices
                 for (var i = 0; i < devices.length; i++) {
                     if (devices[i].DeviceID == deviceCfg.DeviceID) {
-                        folders.push(folderID)
-                        break
+                        folders.push(folderID);
+                        break;
                     }
                 }
             };
+
             folders.sort();
             return folders;
         };

gui/scripts/syncthing/core/services/localeService.js

@@ -12,7 +12,7 @@ angular.module('syncthing.core')
             _availableLocales = locales;
         };
 
-        this.$get = ['$http', '$translate', function ($http, $translate) {
+        this.$get = ['$http', '$translate', '$location', function ($http, $translate, $location) {
 
             /**
              * Requests the server in order to get the browser's requested locale strings.
@@ -26,8 +26,12 @@ angular.module('syncthing.core')
             }
 
             function autoConfigLocale() {
+                var params = $location.search();
 
-                return readBrowserLocales().success(function (langs) {
+                if(params.lang) {
+                    $translate.use(params.lang);
+                } else {
+                    readBrowserLocales().success(function (langs) {
                         // Find the first language in the list provided by the user's browser
                         // that is a prefix of a language we have available. That is, "en"
                         // sent by the browser will match "en" or "en-US", while "zh-TW" will
@@ -35,7 +39,8 @@ angular.module('syncthing.core')
 
                         var i,
                             lang,
-                        matching;
+                            matching,
+                            locale = _defaultLocale;
 
                         for (i = 0; i < langs.length; i++) {
                             lang = langs[i];
@@ -57,14 +62,14 @@ angular.module('syncthing.core')
                             });
 
                             if (matching.length >= 1) {
-                            $translate.use(matching[0]);
-                            return;
+                                locale = matching[0];
+                                break;
                             }
                         }
                         // Fallback if nothing matched
-                    $translate.use(_defaultLocale);
+                        $translate.use(locale);
                     });
-
+                }
             }
 
             function useLocale(language) {