fix(bbb-html5): customHeartbeat would not close stale sessions, + (#19017)

* fix(bbb-html5): customHeartbeat would not close stale sessions, +

The [disabled by default] custom heartbeat included in Meteor's server
does not end connections when they are considered unhealthy/stale, which
deviates a bit from the default implementation. See:
https://github.com/bigbluebutton/bigbluebutton/pull/11486.

This commit includes a call to the default heartbeat termination timeout
so sockets are correctly cleaned up when the custom heartbeat is
activated. It also adds a customHeartbeatUseDataFrames config to allow
controlling whether the custom heartbeat should use WS data frames as
valid heartbeats as well - this should only be useful for
testing/debugging purposes and the default behavior (true) is
maintained.

As a side note: this change spun off from an investigation where some
problematic networks were triggering periodic client re-connects due to
the default heartbeat failing. Investigation points to the control
frames being put alongside fragmented WS data frames and the server side
failing to recognize the former - which means pong frames would be missed and
the health check would fail. Since the default heartbeat _does not_
account for data frame traffic (eg DDP payloads), it would shut down the
client's WS even though it was healthy.
The custom heartbeat _does_ account for data frames, which mitigates
that scenario and prevents unecessary reconnections.

* fix(bbb-html5): frontend crash due to undefined vars in customHeartbeat 

Meteor frontends may crash when customHeartbeat is enabled
due to an undefined access in the heartbeat`s logger.

Add optional chaining to the session props access so it won`t crash and tune down some log levels around that area.

bigbluebutton-html5/imports/startup/server/index.js

@@ -66,41 +66,52 @@ Meteor.startup(() => {
     }, healthCheckInterval);
   }
 
-  const { customHeartbeat } = APP_CONFIG;
+  const { customHeartbeat, customHeartbeatUseDataFrames } = APP_CONFIG;
 
   if (customHeartbeat) {
     Logger.warn('Custom heartbeat functions are enabled');
     // https://github.com/sockjs/sockjs-node/blob/1ef08901f045aae7b4df0f91ef598d7a11e82897/lib/transport/websocket.js#L74-L82
-    const newHeartbeat = function heartbeat() {
+    const heartbeatFactory = function ({ heartbeatTimeoutCallback }) {
+      return function () {
         const currentTime = new Date().getTime();
 
+        if (customHeartbeatUseDataFrames) {
           // Skipping heartbeat, because websocket is sending data
           if (currentTime - this.ws.lastSentFrameTimestamp < 10000) {
             try {
-          Logger.info('Skipping heartbeat, because websocket is sending data', {
+              Logger.debug('Skipping heartbeat, because websocket is sending data', {
                 currentTime,
                 lastSentFrameTimestamp: this.ws.lastSentFrameTimestamp,
-            userId: this.session.connection._meteorSession.userId,
+                userId: this.session?.connection?._meteorSession?.userId,
               });
               return;
             } catch (err) {
               Logger.error(`Skipping heartbeat error: ${err}`);
             }
           }
+        }
+
+        const supportsHeartbeats = this.ws.ping(null, () => {
+          clearTimeout(this.hto_ref);
+        });
 
-      const supportsHeartbeats = this.ws.ping(null, () => clearTimeout(this.hto_ref));
         if (supportsHeartbeats) {
           this.hto_ref = setTimeout(() => {
             try {
-            Logger.info('Heartbeat timeout', { userId: this.session.connection._meteorSession.userId, sentAt: currentTime, now: new Date().getTime() });
+              Logger.warn('Heartbeat timeout', { userId: this.session?.connection?._meteorSession?.userId, sentAt: currentTime, now: new Date().getTime() });
             } catch (err) {
               Logger.error(`Heartbeat timeout error: ${err}`);
+            } finally {
+              if (typeof heartbeatTimeoutCallback === 'function') {
+                heartbeatTimeoutCallback();
+              }
             }
           }, Meteor.server.options.heartbeatTimeout);
         } else {
           Logger.error('Unexpected error supportsHeartbeats=false');
         }
       };
+    };
 
     // https://github.com/davhani/hagty/blob/6a5c78e9ae5a5e4ade03e747fb4cc8ea2df4be0c/faye-websocket/lib/faye/websocket/api.js#L84-L88
     const newSend = function send(data) {
@@ -134,8 +145,10 @@ Meteor.startup(() => {
         }
 
         recv.ws.meteorHeartbeat = session.heartbeat;
-        recv.__proto__.heartbeat = newHeartbeat;
-        recv.ws.__proto__.send = newSend;
+        recv.heartbeat = heartbeatFactory({
+          heartbeatTimeoutCallback: recv.heartbeat_cb
+        });
+        recv.ws.send = newSend;
         session.bbbFixApplied = true;
       }
     }, 5000);

bigbluebutton-html5/private/config/settings.yml

@@ -136,6 +136,7 @@ public:
       breakoutRoomLimit: 16
     # https://github.com/bigbluebutton/bigbluebutton/pull/10826
     customHeartbeat: false
+    customHeartbeatUseDataFrames: true
     showAllAvailableLocales: true
     # Show "Audio Filters for Microphone" option in settings menu.
     # When set to true, users are able to enable/disable microphone constraints,