feat(remotecontrol): UI for requesting permissions

conference.js

@@ -488,11 +488,11 @@ export default {
             }).then(([tracks, con]) => {
                 logger.log('initialized with %s local tracks', tracks.length);
                 APP.connection = connection = con;
+                this.isDesktopSharingEnabled =
+                    JitsiMeetJS.isDesktopSharingEnabled();
                 APP.remoteControl.init();
                 this._bindConnectionFailedHandler(con);
                 this._createRoom(tracks);
-                this.isDesktopSharingEnabled =
-                    JitsiMeetJS.isDesktopSharingEnabled();
 
                 if (UIUtil.isButtonEnabled('contacts')
                     && !interfaceConfig.filmStripOnly) {
@@ -985,7 +985,7 @@ export default {
         let externalInstallation = false;
 
         if (shareScreen) {
-            createLocalTracks({
+            this.screenSharingPromise = createLocalTracks({
                 devices: ['desktop'],
                 desktopSharingExtensionExternalInstallation: {
                     interval: 500,
@@ -1075,7 +1075,9 @@ export default {
             });
         } else {
             APP.remoteControl.receiver.stop();
-            createLocalTracks({ devices: ['video'] }).then(
+            this.screenSharingPromise = createLocalTracks(
+                { devices: ['video'] })
+            .then(
                 ([stream]) => this.useVideoStream(stream)
             ).then(() => {
                 this.videoSwitchInProgress = false;
@@ -1107,6 +1109,8 @@ export default {
             }
         );
 
+        room.on(ConferenceEvents.PARTCIPANT_FEATURES_CHANGED,
+            user => APP.UI.onUserFeaturesChanged(user));
         room.on(ConferenceEvents.USER_JOINED, (id, user) => {
             if (user.isHidden())
                 return;
@@ -1780,6 +1784,7 @@ export default {
      */
     hangup (requestFeedback = false) {
         APP.UI.hideRingOverLay();
+        APP.remoteControl.receiver.enable(false);
         let requestFeedbackPromise = requestFeedback
                 ? APP.UI.requestFeedbackOnHangup()
                 // false - because the thank you dialog shouldn't be displayed

css/_filmstrip.scss

@@ -92,7 +92,7 @@
                 0 0 3px $videoThumbnailSelected !important;
             }
 
-            .remotevideomenu {
+            .remotevideomenu > .icon-menu {
                 display: none;
             }
 
@@ -105,7 +105,7 @@
                 box-shadow: inset 0 0 3px $videoThumbnailHovered,
                 0 0 3px $videoThumbnailHovered;
 
-                .remotevideomenu {
+                .remotevideomenu > .icon-menu {
                     display: inline-block;
                 }
             }

css/_popup_menu.scss

@@ -6,7 +6,6 @@
     padding: 0;
     margin: 2px 0;
     bottom: 0;
-    width: 100px;
     height: auto;
 
     &:first-child {
@@ -67,3 +66,8 @@
 span.remotevideomenu:hover ul.popupmenu, ul.popupmenu:hover {
     display:block !important;
 }
+
+.remote-control-spinner {
+    top: 6px;
+    left: 2px;
+}

lang/main.json

@@ -156,8 +156,8 @@
         "kick": "Kick out",
         "muted": "Muted",
         "domute": "Mute",
-        "flip": "Flip"
+        "flip": "Flip",
-
+        "remoteControl": "Remote control"
     },
     "connectionindicator":
     {
@@ -316,7 +316,12 @@
         "externalInstallationMsg": "You need to install our desktop sharing extension.",
         "muteParticipantTitle": "Mute this participant?",
         "muteParticipantBody": "You won't be able to unmute them, but they can unmute themselves at any time.",
-        "muteParticipantButton": "Mute"
+        "muteParticipantButton": "Mute",
+        "remoteControlTitle": "Remote Control",
+        "remoteControlDeniedMessage": "__user__ rejected your remote control request!",
+        "remoteControlAllowedMessage": "__user__ accepted your remote control request!",
+        "remoteControlErrorMessage": "An error occurred while trying to request remote control permissions from __user__!",
+        "remoteControlStopMessage": "The remote control session ended!"
     },
     "email":
     {

modules/UI/UI.js

@@ -1441,4 +1441,11 @@ UI.hideUserMediaPermissionsGuidanceOverlay = function () {
     GumPermissionsOverlay.hide();
 };
 
+/**
+ * Handles user's features changes.
+ */
+UI.onUserFeaturesChanged = function (user) {
+    VideoLayout.onUserFeaturesChanged(user);
+};
+
 module.exports = UI;

modules/UI/videolayout/RemoteVideo.js

@@ -29,6 +29,7 @@ function RemoteVideo(user, VideoLayout, emitter) {
     this.videoSpanId = `participant_${this.id}`;
     SmallVideo.call(this, VideoLayout);
     this.hasRemoteVideoMenu = false;
+    this._supportsRemoteControl = false;
     this.addRemoteVideoContainer();
     this.connectionIndicator = new ConnectionIndicator(this, this.id);
     this.setDisplayName();
@@ -64,7 +65,7 @@ RemoteVideo.prototype.addRemoteVideoContainer = function() {
 
     this.initBrowserSpecificProperties();
 
-    if (APP.conference.isModerator) {
+    if (APP.conference.isModerator || this._supportsRemoteControl) {
         this.addRemoteVideoMenu();
     }
 
@@ -106,14 +107,6 @@ RemoteVideo.prototype._initPopupMenu = function (popupMenuElement) {
         // call the original show, passing its actual this
         origShowFunc.call(this.popover);
     }.bind(this);
-
-    // override popover hide method so we can cleanup click handlers
-    let origHideFunc = this.popover.forceHide;
-    this.popover.forceHide = function () {
-        $(document).off("click", '#mutelink_' + this.id);
-        $(document).off("click", '#ejectlink_' + this.id);
-        origHideFunc.call(this.popover);
-    }.bind(this);
 };
 
 /**
@@ -139,7 +132,9 @@ RemoteVideo.prototype._generatePopupContent = function () {
     let popupmenuElement = document.createElement('ul');
     popupmenuElement.className = 'popupmenu';
     popupmenuElement.id = `remote_popupmenu_${this.id}`;
+    let menuItems = [];
 
+    if(APP.conference.isModerator) {
         let muteTranslationKey;
         let muteClassName;
         if (this.isAudioMuted) {
@@ -153,7 +148,7 @@ RemoteVideo.prototype._generatePopupContent = function () {
         let muteHandler = this._muteHandler.bind(this);
         let kickHandler = this._kickHandler.bind(this);
 
-    let menuItems = [
+        menuItems = [
             {
                 id: 'mutelink_' + this.id,
                 handler: muteHandler,
@@ -171,6 +166,34 @@ RemoteVideo.prototype._generatePopupContent = function () {
                 }
             }
         ];
+    }
+
+    if(this._supportsRemoteControl) {
+        let icon, handler, className;
+        if(APP.remoteControl.controller.getRequestedParticipant()
+            === this.id) {
+            handler = () => {};
+            className = "requestRemoteControlLink disabled";
+            icon = "remote-control-spinner fa fa-spinner fa-spin";
+        } else if(!APP.remoteControl.controller.isStarted()) {
+            handler = this._requestRemoteControlPermissions.bind(this);
+            icon = "fa fa-play";
+            className = "requestRemoteControlLink";
+        } else {
+            handler = this._stopRemoteControl.bind(this);
+            icon = "fa fa-stop";
+            className = "requestRemoteControlLink";
+        }
+        menuItems.push({
+            id: 'remoteControl_' + this.id,
+            handler,
+            icon,
+            className,
+            data: {
+                i18n: 'videothumbnail.remoteControl'
+            }
+        });
+    }
 
     menuItems.forEach(el => {
         let menuItem = this._generatePopupMenuItem(el);
@@ -182,6 +205,68 @@ RemoteVideo.prototype._generatePopupContent = function () {
     return popupmenuElement;
 };
 
+/**
+ * Sets the remote control supported value and initializes or updates the menu
+ * depending on the remote control is supported or not.
+ * @param {boolean} isSupported
+ */
+RemoteVideo.prototype.setRemoteControlSupport = function(isSupported = false) {
+    if(this._supportsRemoteControl === isSupported) {
+        return;
+    }
+    this._supportsRemoteControl = isSupported;
+    if(!isSupported) {
+        return;
+    }
+
+    if(!this.hasRemoteVideoMenu) {
+        //create menu
+        this.addRemoteVideoMenu();
+    } else {
+        //update the content
+        this.updateRemoteVideoMenu(this.isAudioMuted, true);
+    }
+
+};
+
+/**
+ * Requests permissions for remote control session.
+ */
+RemoteVideo.prototype._requestRemoteControlPermissions = function () {
+    APP.remoteControl.controller.requestPermissions(this.id).then(result => {
+        if(result === null) {
+            return;
+        }
+        this.updateRemoteVideoMenu(this.isAudioMuted, true);
+        APP.UI.messageHandler.openMessageDialog(
+            "dialog.remoteControlTitle",
+            (result === false) ? "dialog.remoteControlDeniedMessage"
+                : "dialog.remoteControlAllowedMessage",
+            {user: this.user.getDisplayName()
+                || interfaceConfig.DEFAULT_REMOTE_DISPLAY_NAME}
+        );
+    }, error => {
+        logger.error(error);
+        this.updateRemoteVideoMenu(this.isAudioMuted, true);
+        APP.UI.messageHandler.openMessageDialog(
+            "dialog.remoteControlTitle",
+            "dialog.remoteControlErrorMessage",
+            {user: this.user.getDisplayName()
+                || interfaceConfig.DEFAULT_REMOTE_DISPLAY_NAME}
+        );
+    });
+    this.updateRemoteVideoMenu(this.isAudioMuted, true);
+};
+
+/**
+ * Stops remote control session.
+ */
+RemoteVideo.prototype._stopRemoteControl = function () {
+    // send message about stopping
+    APP.remoteControl.controller.stop();
+    this.updateRemoteVideoMenu(this.isAudioMuted, true);
+};
+
 RemoteVideo.prototype._muteHandler = function () {
     if (this.isAudioMuted)
         return;
@@ -244,8 +329,7 @@ RemoteVideo.prototype._generatePopupMenuItem = function (opts = {}) {
     linkItem.appendChild(textContent);
     linkItem.id = id;
 
-    // Delegate event to the document.
+    linkItem.onclick = handler;
-    $(document).on("click", `#${id}`, handler);
     menuItem.appendChild(linkItem);
 
     return menuItem;

modules/UI/videolayout/VideoLayout.js

@@ -406,6 +406,7 @@ var VideoLayout = {
             remoteVideo = smallVideo;
         else
             remoteVideo = new RemoteVideo(user, VideoLayout, eventEmitter);
+        this._setRemoteControlProperties(user, remoteVideo);
         this.addRemoteVideoContainer(id, remoteVideo);
     },
 
@@ -1158,12 +1159,36 @@ var VideoLayout = {
      * Sets the flipX state of the local video.
      * @param {boolean} true for flipped otherwise false;
      */
-    setLocalFlipX: function (val) {
+    setLocalFlipX (val) {
         this.localFlipX = val;
-
     },
 
-    getEventEmitter: () => {return eventEmitter;}
+    getEventEmitter() {return eventEmitter;},
+
+    /**
+     * Handles user's features changes.
+     */
+    onUserFeaturesChanged (user) {
+        let video = this.getSmallVideo(user.getId());
+
+        if (!video) {
+            return;
+        }
+        this._setRemoteControlProperties(user, video);
+    },
+
+    /**
+     * Sets the remote control properties (checks whether remote control
+     * is supported and executes remoteVideo.setRemoteControlSupport).
+     * @param {JitsiParticipant} user the user that will be checked for remote
+     * control support.
+     * @param {RemoteVideo} remoteVideo the remoteVideo on which the properties
+     * will be set.
+     */
+    _setRemoteControlProperties (user, remoteVideo) {
+        APP.remoteControl.checkUserRemoteControlSupport(user).then(result =>
+            remoteVideo.setRemoteControlSupport(result));
+    }
 };
 
 export default VideoLayout;

modules/remotecontrol/Controller.js

@@ -55,20 +55,34 @@ export default class Controller extends RemoteControlParticipant {
         super();
         this.controlledParticipant = null;
         this.requestedParticipant = null;
-        this.stopListener = this._handleRemoteControlStoppedEvent.bind(this);
+        this._stopListener = this._handleRemoteControlStoppedEvent.bind(this);
+        this._userLeftListener = this._onUserLeft.bind(this);
     }
 
     /**
      * Requests permissions from the remote control receiver side.
      * @param {string} userId the user id of the participant that will be
      * requested.
+     * @returns {Promise<boolean>} - resolve values:
+     * true - accept
+     * false - deny
+     * null - the participant has left.
      */
     requestPermissions(userId) {
         if(!this.enabled) {
             return Promise.reject(new Error("Remote control is disabled!"));
         }
         return new Promise((resolve, reject) => {
-            let permissionsReplyListener = (participant, event) => {
+            const clearRequest = () => {
+                this.requestedParticipant = null;
+                APP.conference.removeConferenceListener(
+                    ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED,
+                    permissionsReplyListener);
+                APP.conference.removeConferenceListener(
+                    ConferenceEvents.USER_LEFT,
+                    onUserLeft);
+            };
+            const permissionsReplyListener = (participant, event) => {
                 let result = null;
                 try {
                     result = this._handleReply(participant, event);
@@ -76,25 +90,27 @@ export default class Controller extends RemoteControlParticipant {
                     reject(e);
                 }
                 if(result !== null) {
-                    this.requestedParticipant = null;
+                    clearRequest();
-                    APP.conference.removeConferenceListener(
-                        ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED,
-                        permissionsReplyListener);
                     resolve(result);
                 }
             };
+            const onUserLeft = (id) => {
+                if(id === this.requestedParticipant) {
+                    clearRequest();
+                    resolve(null);
+                }
+            };
             APP.conference.addConferenceListener(
                 ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED,
                 permissionsReplyListener);
+            APP.conference.addConferenceListener(ConferenceEvents.USER_LEFT,
+                onUserLeft);
             this.requestedParticipant = userId;
             this._sendRemoteControlEvent(userId, {
                 type: EVENT_TYPES.permissions,
                 action: PERMISSIONS_ACTIONS.request
             }, e => {
-                APP.conference.removeConferenceListener(
+                clearRequest();
-                    ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED,
-                    permissionsReplyListener);
-                this.requestedParticipant = null;
                 reject(e);
             });
         });
@@ -112,13 +128,17 @@ export default class Controller extends RemoteControlParticipant {
         if(this.enabled && event.type === REMOTE_CONTROL_EVENT_TYPE
             && remoteControlEvent.type === EVENT_TYPES.permissions
             && userId === this.requestedParticipant) {
-            if(remoteControlEvent.action === PERMISSIONS_ACTIONS.grant) {
+            switch(remoteControlEvent.action) {
+                case PERMISSIONS_ACTIONS.grant: {
                     this.controlledParticipant = userId;
                     this._start();
                     return true;
-            } else if(remoteControlEvent.action === PERMISSIONS_ACTIONS.deny) {
+                }
+                case PERMISSIONS_ACTIONS.deny:
                     return false;
-            } else {
+                case PERMISSIONS_ACTIONS.error:
+                    throw new Error("Error occurred on receiver side");
+                default:
                     throw new Error("Unknown reply received!");
             }
         } else {
@@ -149,7 +169,9 @@ export default class Controller extends RemoteControlParticipant {
             return;
         APP.conference.addConferenceListener(
             ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED,
-            this.stopListener);
+            this._stopListener);
+        APP.conference.addConferenceListener(ConferenceEvents.USER_LEFT,
+            this._userLeftListener);
         this.area = $("#largeVideoWrapper");
         this.area.mousemove(event => {
             const position = this.area.position();
@@ -179,12 +201,17 @@ export default class Controller extends RemoteControlParticipant {
     }
 
     /**
-     * Stops processing the mouse and keyboard events.
+     * Stops processing the mouse and keyboard events. Removes added listeners.
      */
     _stop() {
+        if(!this.controlledParticipant) {
+            return;
+        }
         APP.conference.removeConferenceListener(
             ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED,
-            this.stopListener);
+            this._stopListener);
+        APP.conference.removeConferenceListener(ConferenceEvents.USER_LEFT,
+            this._userLeftListener);
         this.controlledParticipant = null;
         this.area.off( "mousemove" );
         this.area.off( "mousedown" );
@@ -194,6 +221,23 @@ export default class Controller extends RemoteControlParticipant {
         $(window).off( "keydown");
         $(window).off( "keyup");
         this.area[0].onmousewheel = undefined;
+        APP.UI.messageHandler.openMessageDialog(
+            "dialog.remoteControlTitle",
+            "dialog.remoteControlStopMessage"
+        );
+    }
+
+    /**
+     * Calls this._stop() and sends stop message to the controlled participant.
+     */
+    stop() {
+        if(!this.controlledParticipant) {
+            return;
+        }
+        this._sendRemoteControlEvent(this.controlledParticipant, {
+            type: EVENT_TYPES.stop
+        });
+        this._stop();
     }
 
     /**
@@ -208,6 +252,22 @@ export default class Controller extends RemoteControlParticipant {
         });
     }
 
+    /**
+     * Returns true if the remote control session is started.
+     * @returns {boolean}
+     */
+    isStarted() {
+        return this.controlledParticipant !== null;
+    }
+
+    /**
+     * Returns the id of the requested participant
+     * @returns {string} this.requestedParticipant
+     */
+    getRequestedParticipant() {
+        return this.requestedParticipant;
+    }
+
     /**
      * Handler for key press events.
      * @param {String} type the type of event ("keydown"/"keyup")
@@ -220,4 +280,14 @@ export default class Controller extends RemoteControlParticipant {
             modifiers: getModifiers(event),
         });
     }
+
+    /**
+     * Calls the stop method if the other side have left.
+     * @param {string} id - the user id for the participant that have left
+     */
+    _onUserLeft(id) {
+        if(this.controlledParticipant === id) {
+            this._stop();
+        }
+    }
 }

modules/remotecontrol/Receiver.js

@@ -1,4 +1,4 @@
-/* global APP, JitsiMeetJS */
+/* global APP, JitsiMeetJS, interfaceConfig */
 import {DISCO_REMOTE_CONTROL_FEATURE, REMOTE_CONTROL_EVENT_TYPE, EVENT_TYPES,
     PERMISSIONS_ACTIONS} from "../../service/remotecontrol/Constants";
 import RemoteControlParticipant from "./RemoteControlParticipant";
@@ -21,6 +21,7 @@ export default class Receiver extends RemoteControlParticipant {
         this.controller = null;
         this._remoteControlEventsListener
             = this._onRemoteControlEvent.bind(this);
+        this._userLeftListener = this._onUserLeft.bind(this);
     }
 
     /**
@@ -28,30 +29,60 @@ export default class Receiver extends RemoteControlParticipant {
      * @param {boolean} enabled the new state.
      */
     enable(enabled) {
-        if(this.enabled !== enabled && enabled === true) {
+        if(this.enabled !== enabled) {
             this.enabled = enabled;
+        }
+        if(enabled === true) {
             // Announce remote control support.
             APP.connection.addFeature(DISCO_REMOTE_CONTROL_FEATURE, true);
             APP.conference.addConferenceListener(
                 ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED,
                 this._remoteControlEventsListener);
+        } else {
+            this._stop(true);
+            APP.connection.removeFeature(DISCO_REMOTE_CONTROL_FEATURE);
+            APP.conference.removeConferenceListener(
+                ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED,
+                this._remoteControlEventsListener);
         }
     }
 
     /**
      * Removes the listener for ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED
-     * events.
+     * events. Sends stop message to the wrapper application. Optionally
+     * displays dialog for informing the user that remote control session
+     * ended.
+     * @param {boolean} dontShowDialog - if true the dialog won't be displayed.
+     */
+    _stop(dontShowDialog = false) {
+        if(!this.controller) {
+            return;
+        }
+        this.controller = null;
+        APP.conference.removeConferenceListener(ConferenceEvents.USER_LEFT,
+            this._userLeftListener);
+        APP.API.sendRemoteControlEvent({
+            type: EVENT_TYPES.stop
+        });
+        if(!dontShowDialog) {
+            APP.UI.messageHandler.openMessageDialog(
+                "dialog.remoteControlTitle",
+                "dialog.remoteControlStopMessage"
+            );
+        }
+    }
+
+    /**
+     * Calls this._stop() and sends stop message to the controller participant
      */
     stop() {
-        APP.conference.removeConferenceListener(
+        if(!this.controller) {
-            ConferenceEvents.ENDPOINT_MESSAGE_RECEIVED,
+            return;
-            this._remoteControlEventsListener);
+        }
-        const event = {
+        this._sendRemoteControlEvent(this.controller, {
             type: EVENT_TYPES.stop
-        };
+        });
-        this._sendRemoteControlEvent(this.controller, event);
+        this._stop();
-        this.controller = null;
-        APP.API.sendRemoteControlEvent(event);
     }
 
     /**
@@ -67,9 +98,15 @@ export default class Receiver extends RemoteControlParticipant {
                 && remoteControlEvent.action === PERMISSIONS_ACTIONS.request) {
                 remoteControlEvent.userId = participant.getId();
                 remoteControlEvent.userJID = participant.getJid();
-                remoteControlEvent.displayName = participant.getDisplayName();
+                remoteControlEvent.displayName = participant.getDisplayName()
+                    || interfaceConfig.DEFAULT_REMOTE_DISPLAY_NAME;
+                remoteControlEvent.screenSharing
+                    = APP.conference.isSharingScreen;
             } else if(this.controller !== participant.getId()) {
                 return;
+            } else if(remoteControlEvent.type === EVENT_TYPES.stop) {
+                this._stop();
+                return;
             }
             APP.API.sendRemoteControlEvent(remoteControlEvent);
         }
@@ -83,11 +120,45 @@ export default class Receiver extends RemoteControlParticipant {
      */
     _onRemoteControlPermissionsEvent(userId, action) {
         if(action === PERMISSIONS_ACTIONS.grant) {
+            APP.conference.addConferenceListener(ConferenceEvents.USER_LEFT,
+                this._userLeftListener);
             this.controller = userId;
+            if(!APP.conference.isSharingScreen) {
+                APP.conference.toggleScreenSharing();
+                APP.conference.screenSharingPromise.then(() => {
+                    if(APP.conference.isSharingScreen) {
+                        this._sendRemoteControlEvent(userId, {
+                            type: EVENT_TYPES.permissions,
+                            action: action
+                        });
+                    } else {
+                        this._sendRemoteControlEvent(userId, {
+                            type: EVENT_TYPES.permissions,
+                            action: PERMISSIONS_ACTIONS.error
+                        });
+                    }
+                }).catch(() => {
+                    this._sendRemoteControlEvent(userId, {
+                        type: EVENT_TYPES.permissions,
+                        action: PERMISSIONS_ACTIONS.error
+                    });
+                });
+                return;
+            }
         }
         this._sendRemoteControlEvent(userId, {
             type: EVENT_TYPES.permissions,
             action: action
         });
     }
+
+    /**
+     * Calls the stop method if the other side have left.
+     * @param {string} id - the user id for the participant that have left
+     */
+    _onUserLeft(id) {
+        if(this.controller === id) {
+            this._stop();
+        }
+    }
 }

modules/remotecontrol/RemoteControl.js

@@ -1,7 +1,7 @@
 /* global APP, config */
 import Controller from "./Controller";
 import Receiver from "./Receiver";
-import {EVENT_TYPES}
+import {EVENT_TYPES, DISCO_REMOTE_CONTROL_FEATURE}
     from "../../service/remotecontrol/Constants";
 
 /**
@@ -24,7 +24,8 @@ class RemoteControl {
      * enabled or not, initializes the API module.
      */
     init() {
-        if(config.disableRemoteControl || this.initialized) {
+        if(config.disableRemoteControl || this.initialized
+            || !APP.conference.isDesktopSharingEnabled) {
             return;
         }
         this.initialized = true;
@@ -32,6 +33,9 @@ class RemoteControl {
             forceEnable: true,
         });
         this.controller.enable(true);
+        if(this.enabled) { // supported message came before init.
+            this._onRemoteControlSupported();
+        }
     }
 
     /**
@@ -62,6 +66,18 @@ class RemoteControl {
             }
         }
     }
+
+    /**
+     * Checks whether the passed user supports remote control or not
+     * @param {JitsiParticipant} user the user to be tested
+     * @returns {Promise<boolean>} the promise will be resolved with true if
+     * the user supports remote control and with false if not.
+     */
+    checkUserRemoteControlSupport(user) {
+        return user.getFeatures().then(features =>
+            features.has(DISCO_REMOTE_CONTROL_FEATURE), () => false
+        );
+    }
 }
 
 export default new RemoteControl();

service/remotecontrol/Constants.js

@@ -26,7 +26,8 @@ export const EVENT_TYPES = {
 export const PERMISSIONS_ACTIONS = {
     request: "request",
     grant: "grant",
-    deny: "deny"
+    deny: "deny",
+    error: "error"
 };
 
 /**