feat(external-api): add knocking event and approve/reject command (#10210)

modules/API/API.js

     captureLargeVideoScreenshot,
     resizeLargeVideo
 } from '../../react/features/large-video/actions.web';
-import { toggleLobbyMode } from '../../react/features/lobby/actions';
+import { toggleLobbyMode, setKnockingParticipantApproval } from '../../react/features/lobby/actions';
 import { isForceMuted } from '../../react/features/participants-pane/functions';
 import { RECORDING_TYPES } from '../../react/features/recording/constants';
 import { getActiveSession } from '../../react/features/recording/functions';
  */
 function initCommands() {
     commands = {
+        'answer-knocking-participant': (id, approved) => {
+            APP.store.dispatch(setKnockingParticipantApproval(id, approved));
+        },
         'approve-video': participantId => {
             if (!isLocalParticipantModerator(APP.store.getState())) {
                 return;
         });
     }
 
+    /**
+     * Notify external application (if API is enabled) that a participant is knocking in the lobby.
+     *
+     * @param {Object} participant - Participant data such as id and name.
+     * @returns {void}
+     */
+    notifyKnockingParticipant(participant: Object) {
+        this._sendEvent({
+            name: 'knocking-participant',
+            participant
+        });
+    }
+
     /**
      * Notify external application (if API is enabled) that an error occured.
      *

modules/API/external/external_api.js

  * commands expected by jitsi-meet
  */
 const commands = {
+    answerKnockingParticipant: 'answer-knocking-participant',
     approveVideo: 'approve-video',
     askToUnmute: 'ask-to-unmute',
     avatarUrl: 'avatar-url',
     'feedback-prompt-displayed': 'feedbackPromptDisplayed',
     'filmstrip-display-changed': 'filmstripDisplayChanged',
     'incoming-message': 'incomingMessage',
+    'knocking-participant': 'knockingParticipant',
     'log': 'log',
     'mic-error': 'micError',
     'moderation-participant-approved': 'moderationParticipantApproved',

react/features/lobby/middleware.js

 import { KNOCKING_PARTICIPANT_SOUND_ID } from './constants';
 import { KNOCKING_PARTICIPANT_FILE } from './sounds';
 
+declare var APP: Object;
+
 MiddlewareRegistry.register(store => next => action => {
     switch (action.type) {
     case APP_WILL_MOUNT:
                         name
                     }));
                     dispatch(playSound(KNOCKING_PARTICIPANT_SOUND_ID));
+                    if (typeof APP !== 'undefined') {
+                        APP.API.notifyKnockingParticipant({
+                            id,
+                            name
+                        });
+                    }
                 });
             });