Handles unique Id for a meeting.

JitsiConference.js

@@ -2122,6 +2122,17 @@ JitsiConference.prototype.getPhonePin = function() {
     return null;
 };
 
+/**
+ * Returns the meeting unique Id if any.
+ */
+JitsiConference.prototype.getMeetingUniqueId = function() {
+    if (this.room) {
+        return this.room.getMeetingId();
+    }
+
+    return null;
+};
+
 /**
  * Will return P2P or JVB <tt>TraceablePeerConnection</tt> depending on
  * which connection is currently active.

modules/xmpp/ChatRoom.js

@@ -127,6 +127,7 @@ export default class ChatRoom extends Listenable {
 
         this.locked = false;
         this.transcriptionStatus = JitsiTranscriptionStatus.OFF;
+        this.meetingId = null;
     }
 
     /* eslint-enable max-params */
@@ -277,6 +278,22 @@ export default class ChatRoom extends Listenable {
                 this.eventEmitter.emit(XMPPEvents.MUC_LOCK_CHANGED, locked);
                 this.locked = locked;
             }
+
+            const meetingIdValEl
+                = $(result).find('>query>x[type="result"]>field[var="muc#roominfo_meetingId"]>value');
+
+            if (meetingIdValEl.length) {
+                const meetingId = meetingIdValEl.text();
+
+                if (this.meetingId !== meetingId) {
+                    if (this.meetingId) {
+                        logger.warn(`Meeting Id changed from:${this.meetingId} to:${meetingId}`);
+                    }
+                    this.meetingId = meetingId;
+                }
+            } else {
+                logger.trace('No meeting id from backend');
+            }
         }, error => {
             GlobalOnErrorHandler.callErrorHandler(error);
             logger.error('Error getting room info: ', error);
@@ -478,6 +495,10 @@ export default class ChatRoom extends Listenable {
                 this.sendPresence();
 
                 this.eventEmitter.emit(XMPPEvents.MUC_JOINED);
+
+                // Now let's check the disco-info to retrieve the
+                // meeting Id if any
+                this.discoRoomInfo();
             }
         } else if (jid === undefined) {
             logger.info('Ignoring member with undefined JID');
@@ -1363,6 +1384,13 @@ export default class ChatRoom extends Listenable {
         return this.phonePin;
     }
 
+    /**
+     * Returns the meeting unique Id if any came from backend.
+     */
+    getMeetingId() {
+        return this.meetingId;
+    }
+
     /**
      * Mutes remote participant.
      * @param jid of the participant