GUACAMOLE-567: Warn user when tunnel enters "UNSTABLE" state.

guacamole/src/main/webapp/app/client/controllers/clientController.js

@@ -626,6 +626,18 @@ angular.module('client').controller('clientController', ['$scope', '$routeParams
 
     };
 
+    /**
+     * Returns whether the current connection has been flagged as unstable due
+     * to an apparent network disruption.
+     *
+     * @returns {Boolean}
+     *     true if the current connection has been flagged as unstable, false
+     *     otherwise.
+     */
+    $scope.isConnectionUnstable = function isConnectionUnstable() {
+        return $scope.client && $scope.client.clientState.connectionState === ManagedClientState.ConnectionState.UNSTABLE;
+    };
+
     // Show status dialog when connection status changes
     $scope.$watch('client.clientState.connectionState', function clientStateChanged(connectionState) {
 

guacamole/src/main/webapp/app/client/styles/connection-warning.css

@@ -0,0 +1,36 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#connection-warning {
+
+    position: absolute;
+    right: 0.25em;
+    top: 0.25em;
+    z-index: 20;
+
+    max-width: 100%;
+    max-height: 3in;
+
+    border: 1px solid rgba(0,0,0,0.5);
+    box-shadow: 1px 1px 2px rgba(0,0,0,0.25);
+    background: #FFE;
+    padding: 0.5em;
+    font-size: .8em;
+
+}

guacamole/src/main/webapp/app/client/templates/client.html

@@ -36,6 +36,11 @@
         <guac-file-transfer-manager client="client"></guac-file-transfer-manager>
     </div>
 
+    <!-- Connection stability warning -->
+    <div id="connection-warning" ng-show="isConnectionUnstable()">
+        {{'CLIENT.TEXT_CLIENT_STATUS_UNSTABLE' | translate}}
+    </div>
+
     <!-- Menu -->
     <div class="menu" ng-class="{open: menu.shown}" id="guac-menu">
         <div class="menu-content" ng-if="menu.shown">

guacamole/src/main/webapp/app/client/types/ManagedClient.js

@@ -346,6 +346,18 @@ angular.module('client').factory('ManagedClient', ['$rootScope', '$injector',
                             ManagedClientState.ConnectionState.CONNECTING);
                         break;
 
+                    // Connection is established
+                    case Guacamole.Tunnel.State.OPEN:
+                        ManagedClientState.setConnectionState(managedClient.clientState,
+                            ManagedClientState.ConnectionState.CONNECTED);
+                        break;
+
+                    // Connection is established but misbehaving
+                    case Guacamole.Tunnel.State.UNSTABLE:
+                        ManagedClientState.setConnectionState(managedClient.clientState,
+                            ManagedClientState.ConnectionState.UNSTABLE);
+                        break;
+
                     // Connection has closed
                     case Guacamole.Tunnel.State.CLOSED:
                         ManagedClientState.setConnectionState(managedClient.clientState,

guacamole/src/main/webapp/app/client/types/ManagedClientState.js

@@ -88,11 +88,20 @@ angular.module('client').factory('ManagedClientState', [function defineManagedCl
         /**
          * The Guacamole connection has been successfully established, and
          * initial graphical data has been received.
-         * 
+         *
          * @type String
          */
         CONNECTED : "CONNECTED",
 
+        /**
+         * The Guacamole connection has been successfully established, but the
+         * network connection seems unstable. The connection may perform poorly
+         * or disconnect.
+         * 
+         * @type String
+         */
+        UNSTABLE : "UNSTABLE",
+
         /**
          * The Guacamole connection has terminated successfully. No errors are
          * indicated.

guacamole/src/main/webapp/translations/en.json

@@ -137,6 +137,7 @@
         "TEXT_CLIENT_STATUS_IDLE"         : "Idle.",
         "TEXT_CLIENT_STATUS_CONNECTING"   : "Connecting to Guacamole...",
         "TEXT_CLIENT_STATUS_DISCONNECTED" : "You have been disconnected.",
+        "TEXT_CLIENT_STATUS_UNSTABLE"     : "The network connection to the Guacamole server appears unstable.",
         "TEXT_CLIENT_STATUS_WAITING"      : "Connected to Guacamole. Waiting for response...",
         "TEXT_RECONNECT_COUNTDOWN"        : "Reconnecting in {REMAINING} {REMAINING, plural, one{second} other{seconds}}...",
         "TEXT_FILE_TRANSFER_PROGRESS"     : "{PROGRESS} {UNIT, select, b{B} kb{KB} mb{MB} gb{GB} other{}}",