Websocket connection overhaul, touch #456.

.env.sample

@@ -66,4 +66,9 @@ PROXY_SERVER_TIMEOUT =
 
 # WebSocket config
 WS_ENABLE = true
-WS_URL =
+WS_RECONNECT = true
+WS_REJECT_UNAUTHORIZED = false
+WS_PING_TIMEOUT = 16000
+WS_RECONNECT_INTERVAL = 3000
+WS_URL =
+WS_SECRET =

.gitignore

@@ -3,6 +3,7 @@ log/
 tests/_temp
 tmp/
 dist/
+cert/
 
 .DS_Store
 .cache

lib/envConfig.js

@@ -0,0 +1,16 @@
+import { z } from 'zod';
+
+const envToBoolean = () =>
+  z.enum(['true', 'false']).transform((v) => v === 'true');
+
+const EnvConfig = z.object({
+  WS_ENABLE: envToBoolean(),
+  WS_RECONNECT: envToBoolean(),
+  WS_REJECT_UNAUTHORIZED: envToBoolean(),
+  WS_PING_TIMEOUT: z.coerce.number(),
+  WS_RECONNECT_INTERVAL: z.coerce.number(),
+  WS_URL: z.string(),
+  WS_SECRET: z.string()
+});
+
+export const envConfig = EnvConfig.parse(process.env);

lib/schemas/config.js

@@ -317,7 +317,7 @@ export const defaultConfig = {
         description: 'The port on which to run the SSL server.'
       },
       certPath: {
-        envLink: 'HIGHCHARTS_SSL_CERT_PATH',
+        envLink: 'HIGHCHARTS_SERVER_SSL_CERT_PATH',
         value: '',
         type: 'string',
         description: 'The path to the SSL certificate/key.'

lib/server/routes/export.js

@@ -13,6 +13,7 @@ See LICENSE file in root for details.
 *******************************************************************************/
 
 import { v4 as uuid } from 'uuid';
+import { WebSocket } from 'ws';
 
 import websocket from '../websocket.js';
 import { getAllowCodeExecution, startExport } from '../../chart.js';
@@ -255,7 +256,7 @@ const exportHandler = (request, response) => {
   }
 
   // If the client is found, send data through WebSocket
-  if (websocketClient) {
+  if (websocketClient && websocketClient.readyState === WebSocket.OPEN) {
     // Already prepared options but before the export process
     websocketClient.send(JSON.stringify(options));
   }

lib/server/server.js

@@ -18,14 +18,16 @@ import { posix } from 'path';
 import bodyParser from 'body-parser';
 import cors from 'cors';
 import express from 'express';
-import multer from 'multer';
 import http from 'http';
 import https from 'https';
+import jwt from 'jsonwebtoken';
+import multer from 'multer';
 
 import rateLimit from './rate_limit.js';
 import websocket from './websocket.js';
+import { envConfig } from '../envConfig.js';
 import { log } from '../logger.js';
-import { toBoolean, __dirname } from '../utils.js';
+import { __dirname } from '../utils.js';
 
 import healthRoute from './routes/health.js';
 import exportRoutes from './routes/export.js';
@@ -84,23 +86,8 @@ export const startServer = async (serverConfig) => {
     return false;
   }
 
-  // // Get the pool
-  // const pool = getPool();
-
-  // // Try to create browser instance before starting the server
-  // const resource = await pool.acquire();
-
-  // // If not found, throw an error
-  // if (!resource.browser) {
-  //   log(1, `[server] Could not acquire browser instance.`);
-  //   process.exit(1);
-  // }
-
-  // // Release the resource
-  // pool.release(resource);
-
-  // Listen HTTP server
-  if (!serverConfig.ssl.enable && !serverConfig.ssl.force) {
+  // Listen HTTP server, if TLS is not forced
+  if (!serverConfig.ssl.force) {
     // Main server instance (HTTP)
     const httpServer = http.createServer(app);
     // Attach error handlers and listen to the server
@@ -140,7 +127,7 @@ export const startServer = async (serverConfig) => {
 
     if (key && cert) {
       // Main server instance (HTTPS)
-      const httpsServer = https.createServer(app);
+      const httpsServer = https.createServer({ key, cert }, app);
       // Attach error handlers and listen to the server
       attachErrorHandlers(httpsServer);
       // Listen
@@ -172,8 +159,17 @@ export const startServer = async (serverConfig) => {
   vswitchRoute(app);
 
   // Set the WebSocket connection if enabled
-  if (toBoolean(process.env.WS_ENABLE) == true) {
-    websocket.connect(process.env.WS_URL);
+  if (envConfig.WS_ENABLE == true) {
+    websocket.connect(envConfig.WS_URL, {
+      rejectUnauthorized: envConfig.WS_REJECT_UNAUTHORIZED,
+      headers: {
+        // Set an access token that lasts only 5 minutes
+        auth: jwt.sign({ success: 'success' }, envConfig.WS_SECRET, {
+          algorithm: 'HS256',
+          expiresIn: '5m'
+        })
+      }
+    });
   }
 };
 

lib/server/websocket.js

@@ -13,46 +13,90 @@ See LICENSE file in root for details.
 *******************************************************************************/
 import WebSocket from 'ws';
 
-import { log } from '../../lib/logger.js';
+import { log } from '../logger.js';
+import { envConfig } from '../envConfig.js';
 
+// WebSocket client
 let webSocket;
 
+// In case of closing or termination of a client connection
+let reconnectInterval;
+
+/**
+ * Connects to WebSocket on a provided url.
+ *
+ * @param {string} webSocketUrl - The WebSocket server's URL.
+ * @param {object} options - Options for WebSocket connection.
+ */
+function connect(webSocketUrl, options) {
+  // Try to connect to indicated WebSocket server
+  webSocket = new WebSocket(webSocketUrl, options);
+
+  // Open event
+  webSocket.on('open', () => {
+    log(3, `[websocket] Connected to WebSocket server: ${webSocketUrl}`);
+    clearInterval(reconnectInterval);
+  });
+
+  // Close event where ping timeout is cleared
+  webSocket.on('close', (code) => {
+    log(
+      3,
+      '[websocket]',
+      `Disconnected from WebSocket server: ${webSocketUrl} with code: ${code}`
+    );
+    clearTimeout(webSocket._pingTimeout);
+    webSocket = null;
+  });
+
+  // Error event
+  webSocket.on('error', (error) => {
+    log(1, `[websocket] WebSocket error occured: ${error.message}`);
+  });
+
+  // Message event
+  webSocket.on('message', (message) => {
+    log(3, `[websocket] Data received: ${message}`);
+  });
+
+  // Ping event with the connection health check and termination logic
+  webSocket.on('ping', () => {
+    log(3, '[websocket] PING');
+    clearTimeout(webSocket._pingTimeout);
+    webSocket._pingTimeout = setTimeout(() => {
+      // Terminate the client connection
+      webSocket.terminate();
+
+      // Try to reconnect if required
+      if (envConfig.WS_RECONNECT === true) {
+        reconnect(webSocketUrl, options);
+      }
+    }, envConfig.WS_PING_TIMEOUT);
+  });
+}
+
+/**
+ * Re-connects to WebSocket on a provided url.
+ *
+ * @param {string} webSocketUrl - The WebSocket server's URL.
+ * @param {object} options - Options for WebSocket connection.
+ */
+function reconnect(webSocketUrl, options) {
+  reconnectInterval = setInterval(() => {
+    if (webSocket === null) {
+      connect(webSocketUrl, options);
+    }
+  }, envConfig.WS_RECONNECT_INTERVAL);
+}
+
+/**
+ * Gets the instance of the WebSocket connection.
+ */
+function getClient() {
+  return webSocket;
+}
+
 export default {
-  /**
-   * Connects to WebSocket on provided url.
-   *
-   * @param {string} webSocketUrl - The WebSocket server's url.
-   */
-  connect: (webSocketUrl) => {
-    // Try to connect to indicated WebSocket
-    webSocket = new WebSocket(webSocketUrl);
-
-    // Open event handler with message
-    webSocket.on('open', () => {
-      log(3, `[websocket] Connected to WebSocket server: ${webSocketUrl}`);
-    });
-
-    // Close event handler with message and code
-    webSocket.on('close', (code) => {
-      log(
-        3,
-        `[websocket] Disconnected from WebSocket server: ${webSocketUrl} with code: ${code}`
-      );
-    });
-
-    // Error event handler with error message
-    webSocket.on('error', (error) => {
-      log(4, `[websocket] WebSocket error occured: ${error.message}`);
-    });
-
-    // Message event handler
-    webSocket.on('message', (message) => {
-      log(3, `[websocket] Data received: ${message}`);
-    });
-  },
-
-  /**
-   * Gets the instance of the WebSocket connection.
-   */
-  getClient: () => webSocket
+  connect,
+  getClient
 };