[MM 7970] Support maintaining online status while the Desktop App is …

…in the background ... and other things. (#2992)

* listen for os-level user status updates

* typo

actions/global_actions.jsx

@@ -318,4 +318,4 @@ export async function redirectUserToDefaultTeam() {
     } else {
         browserHistory.push('/select_team');
     }
-}
+}

client/websocket_client.jsx

@@ -184,6 +184,14 @@ export default class WebSocketClient {
         this.sendMessage('user_typing', data, callback);
     }
 
+    userUpdateActiveStatus(userIsActive, manual, callback) {
+        const data = {
+            user_is_active: userIsActive,
+            manual,
+        };
+        this.sendMessage('user_update_active_status', data, callback);
+    }
+
     getStatuses(callback) {
         this.sendMessage('get_statuses', null, callback);
     }

components/logged_in/logged_in.jsx

@@ -13,6 +13,8 @@ import * as UserAgent from 'utils/user_agent.jsx';
 import LoadingScreen from 'components/loading_screen.jsx';
 import {getBrowserTimezone} from 'utils/timezone.jsx';
 import store from 'stores/redux_store.jsx';
+import {webappConnector} from 'utils/webapp_connector';
+import WebSocketClient from 'client/web_websocket_client.jsx';
 
 const dispatch = store.dispatch;
 const getState = store.getState;
@@ -69,6 +71,11 @@ export default class LoggedIn extends React.PureComponent {
         window.addEventListener('focus', this.onFocusListener);
         window.addEventListener('blur', this.onBlurListener);
 
+        // Listen for user activity updates from external sources via the webapp connector
+        if (webappConnector.active) {
+            webappConnector.on('user-activity-update', this.handleUserActivityUpdates);
+        }
+
         // Because current CSS requires the root tag to have specific stuff
 
         // Device tracking setup
@@ -132,9 +139,10 @@ export default class LoggedIn extends React.PureComponent {
 
         $(window).off('keydown.preventBackspace');
 
-        // Listen for focussed tab/window state
         window.removeEventListener('focus', this.onFocusListener);
         window.removeEventListener('blur', this.onBlurListener);
+
+        webappConnector.removeListener('user-activity-update', this.handleUserActivityUpdates);
     }
 
     render() {
@@ -164,4 +172,13 @@ export default class LoggedIn extends React.PureComponent {
     onBlurListener() {
         GlobalActions.emitBrowserFocus(false);
     }
+
+    handleUserActivityUpdates = ({userIsActive, manual}) => {
+        if (!this.props.currentUser) {
+            return;
+        }
+
+        // update the server with the users current away status
+        WebSocketClient.userUpdateActiveStatus(userIsActive, manual);
+    }
 }

utils/webapp_connector.js

@@ -0,0 +1,19 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+/**
+ * Create a placeholder webappConnector if one doesn't exist. Likely means we're not running in the desktop client.
+ */
+if (!window.webappConnector) {
+    window.webappConnector = {
+        active: false,
+        on: () => { }, //eslint-disable-line no-empty-function
+        removeListener: () => { }, //eslint-disable-line no-empty-function
+        emit: () => { }, //eslint-disable-line no-empty-function
+    };
+}
+
+/**
+* Returns a reference to the webappConnector if available, or a placeholder object to silently ignore any interaction
+*/
+export const webappConnector = window.webappConnector;