Feature: maintenance mode websocket

package.json

@@ -57,7 +57,8 @@
     "typeorm": "^0.3.20",
     "uuid": "^10.0.0",
     "validator": "^13.12.0",
-    "vitepress-theme-openapi": "^0.0.3-alpha.30"
+    "vitepress-theme-openapi": "^0.0.3-alpha.30",
+    "ws": "^8.18.0"
   },
   "devDependencies": {
     "@apidevtools/swagger-cli": "^4.0.4",
@@ -81,6 +82,7 @@
     "@types/swagger-ui-express": "^4.1.7",
     "@types/uuid": "^10.0.0",
     "@types/validator": "^13.12.2",
+    "@types/ws": "^8.5.14",
     "@typescript-eslint/eslint-plugin": "^7.18.0",
     "@typescript-eslint/parser": "^7.18.0",
     "chai": "^4.3.7",

src/controller/server-settings-controller.ts

@@ -30,6 +30,7 @@ import log4js, { Logger } from 'log4js';
 import Policy from './policy';
 import { RequestWithToken } from '../middleware/token-middleware';
 import ServerSettingsStore from '../server-settings/server-settings-store';
+import WebSocketService from '../service/websocket-service';
 
 /**
  * @typedef {object} UpdateMaintenanceModeRequest
@@ -45,6 +46,7 @@ export default class ServerSettingsController extends BaseController {
   public constructor(options: BaseControllerOptions) {
     super(options);
     this.logger.level = process.env.LOG_LEVEL;
+    WebSocketService.initiateWebSocket();
   }
 
   public getPolicy(): Policy {
@@ -79,6 +81,9 @@ export default class ServerSettingsController extends BaseController {
       const store = ServerSettingsStore.getInstance();
       await store.setSetting('maintenanceMode', body.enabled);
 
+      // Send websocket message to POS
+      WebSocketService.sendMaintenanceMode(body.enabled);
+
       res.status(204).send();
     } catch (error) {
       this.logger.error('Could not update maintenance mode:', error);

src/service/websocket-service.ts

@@ -0,0 +1,58 @@
+/**
+ *  SudoSOS back-end API service.
+ *  Copyright (C) 2024  Study association GEWIS
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as published
+ *  by the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ *  @license
+ */
+
+
+import http from 'http';
+import express from 'express';
+import WebSocket from 'ws';
+import log4js, { Logger } from 'log4js';
+
+/**
+ * This is the module page of the websocket-service.
+ *
+ * @module websocket
+ */
+
+export default class WebSocketService {
+  private static readonly httpServer = http.createServer(express());
+
+  private static webSocketServer = new WebSocket.Server({ server: this.httpServer });
+
+  public static initiateWebSocket(): void {
+    const logger: Logger = log4js.getLogger('LDAP');
+    logger.level = process.env.LOG_LEVEL;
+
+    const port = process.env.WEBSOCKET_PORT || 443;
+    this.httpServer.listen(port);
+    logger.info('Opened WebSocket server on port ' + port);
+
+    this.webSocketServer.on('maintenance-mode', (status) => {
+      this.webSocketServer.clients.forEach((client) => {
+        const message = 'maintenance-mode ' + status;
+        client.send(message);
+        logger.info('Sent \"' + message + '\" over WebSocket');
+      });
+    });
+  }
+
+  public static sendMaintenanceMode(enabled: boolean): void {
+    this.webSocketServer.emit('maintenance-mode', enabled);
+  }
+}