From f5668b6e8be2e79f6f6a968ab6c53d0e03e2c950 Mon Sep 17 00:00:00 2001
From: damencho <damencho@jitsi.org>
Date: Thu, 18 Sep 2025 11:19:49 -0500
Subject: [PATCH] feat(visitors): Retries as a visitor when max occupants
 reached.

---
 .../base/conference/middleware.any.ts         | 40 ++++++++++++++++---
 .../prosody-plugins/mod_muc_max_occupants.lua |  4 +-
 2 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/react/features/base/conference/middleware.any.ts b/react/features/base/conference/middleware.any.ts
index ca58e329ea..ea9cd91aef 100644
--- a/react/features/base/conference/middleware.any.ts
+++ b/react/features/base/conference/middleware.any.ts
@@ -26,7 +26,7 @@ import { AudioMixerEffect } from '../../stream-effects/audio-mixer/AudioMixerEff
 import { iAmVisitor } from '../../visitors/functions';
 import { overwriteConfig } from '../config/actions';
 import { CONNECTION_ESTABLISHED, CONNECTION_FAILED, CONNECTION_WILL_CONNECT } from '../connection/actionTypes';
-import { connectionDisconnected, disconnect } from '../connection/actions';
+import { connect, connectionDisconnected, disconnect, setPreferVisitor } from '../connection/actions';
 import { validateJwt } from '../jwt/functions';
 import { JitsiConferenceErrors, JitsiConferenceEvents, JitsiConnectionErrors } from '../lib-jitsi-meet';
 import { MEDIA_TYPE } from '../media/constants';
@@ -78,6 +78,11 @@ import { IConferenceMetadata } from './reducer';
  */
 let beforeUnloadHandler: ((e?: any) => void) | undefined;
 
+/**
+ * A simple flag to avoid retrying more than once to join as a visitor when hitting max occupants reached.
+ */
+let retryAsVisitorOnMaxError = true;
+
 /**
  * Implements the middleware of the feature base/conference.
  *
@@ -202,11 +207,20 @@ function _conferenceFailed({ dispatch, getState }: IStore, next: Function, actio
         break;
     }
     case JitsiConferenceErrors.CONFERENCE_MAX_USERS: {
-        dispatch(showErrorNotification({
-            hideErrorSupportLink: true,
-            descriptionKey: 'dialog.maxUsersLimitReached',
-            titleKey: 'dialog.maxUsersLimitReachedTitle'
-        }));
+        let retryAsVisitor = false;
+
+        if (error.params?.length && error.params[0]?.visitorsSupported) {
+            // visitors are supported, so let's try joining that way
+            retryAsVisitor = true;
+        }
+
+        if (!retryAsVisitor) {
+            dispatch(showErrorNotification({
+                hideErrorSupportLink: true,
+                descriptionKey: 'dialog.maxUsersLimitReached',
+                titleKey: 'dialog.maxUsersLimitReachedTitle'
+            }));
+        }
 
         // In case of max users(it can be from a visitor node), let's restore
         // oldConfig if any as we will be back to the main prosody.
@@ -220,6 +234,18 @@ function _conferenceFailed({ dispatch, getState }: IStore, next: Function, actio
                 .then(() => dispatch(disconnect()));
         }
 
+        if (retryAsVisitor && !newConfig && retryAsVisitorOnMaxError) {
+            retryAsVisitorOnMaxError = false;
+
+            logger.info('On max user reached will retry joining as a visitor');
+
+            dispatch(disconnect(true)).then(() => {
+                dispatch(setPreferVisitor(true));
+
+                return dispatch(connect());
+            });
+        }
+
         break;
     }
     case JitsiConferenceErrors.NOT_ALLOWED_ERROR: {
@@ -300,6 +326,8 @@ function _conferenceJoined({ dispatch, getState }: IStore, next: Function, actio
         requireDisplayName
     } = getState()['features/base/config'];
 
+    retryAsVisitorOnMaxError = true;
+
     dispatch(removeLobbyChatParticipant(true));
 
     pendingSubjectChange && dispatch(setSubject(pendingSubjectChange));
diff --git a/resources/prosody-plugins/mod_muc_max_occupants.lua b/resources/prosody-plugins/mod_muc_max_occupants.lua
index 63a089736f..4a4892c93e 100644
--- a/resources/prosody-plugins/mod_muc_max_occupants.lua
+++ b/resources/prosody-plugins/mod_muc_max_occupants.lua
@@ -43,7 +43,7 @@ local function check_for_max_occupants(event)
 
 		-- If there is no whitelist, just check the count.
 		if not whitelist and count >= slots then
-			module:log("info", "Attempt to enter a maxed out MUC");
+			module:log("info", "Attempt to enter a maxed out room: %s", room.jid);
 			origin.send(st.error_reply(stanza, "cancel", "service-unavailable"));
 			return true;
 		end
@@ -60,7 +60,7 @@ local function check_for_max_occupants(event)
 
 		-- If the room is full (<0 slots left), error out.
 		if slots <= 0 then
-			module:log("info", "Attempt to enter a maxed out MUC");
+			module:log("info", "Attempt to enter a maxed out room:%s", room.jid);
 			origin.send(st.error_reply(stanza, "cancel", "service-unavailable"));
 			return true;
 		end