Better version change detection (fixes #808, fixes #810)

gui/app.js

@@ -20,10 +20,24 @@
 
 var syncthing = angular.module('syncthing', ['pascalprecht.translate']);
 var urlbase = 'rest';
+var guiVersion = null;
 
 syncthing.config(function ($httpProvider, $translateProvider) {
     $httpProvider.defaults.xsrfHeaderName = 'X-CSRF-Token';
     $httpProvider.defaults.xsrfCookieName = 'CSRF-Token';
+    $httpProvider.interceptors.push(function() {
+      return {
+        response: function(response) {
+            var responseVersion = response.headers()['x-syncthing-version'];
+            if (!guiVersion) {
+                guiVersion = responseVersion;
+            } else if (guiVersion != responseVersion) {
+                document.location.reload(true);
+            }
+            return response;
+        }
+      };
+    });
 
     $translateProvider.useStaticFilesLoader({
         prefix: 'lang/lang-',
@@ -164,17 +178,13 @@ syncthing.controller('SyncthingCtrl', function ($scope, $http, $translate, $loca
             return;
         }
 
-        if (restarting) {
-            document.location.reload(true);
-        } else {
-            console.log('UIOnline');
-            $scope.init();
-            online = true;
-            restarting = false;
-            $('#networkError').modal('hide');
-            $('#restarting').modal('hide');
-            $('#shutdown').modal('hide');
-        }
+        console.log('UIOnline');
+        $scope.init();
+        online = true;
+        restarting = false;
+        $('#networkError').modal('hide');
+        $('#restarting').modal('hide');
+        $('#shutdown').modal('hide');
     });
 
     $scope.$on('UIOffline', function (event, arg) {