backend: implement participant role management and update signals

backend/src/controllers/participant.controller.ts

@@ -132,3 +132,18 @@ export const deleteParticipant = async (req: Request, res: Response) => {
 		handleError(res, error, `deleting participant '${participantName}' from room '${roomId}'`);
 	}
 };
+
+export const changeParticipantRole = async (req: Request, res: Response) => {
+	const logger = container.get(LoggerService);
+	const participantService = container.get(ParticipantService);
+	const { roomId, participantName } = req.params;
+	const { role } = req.body;
+
+	try {
+		logger.verbose(`Changing role of participant '${participantName}' in room '${roomId}' to '${role}'`);
+		await participantService.changeParticipantRole(roomId, participantName, role);
+		res.status(200).json({ message: `Participant '${participantName}' role updated to ${role}` });
+	} catch (error) {
+		handleError(res, error, `changing role for participant '${participantName}' in room '${roomId}'`);
+	}
+};

backend/src/helpers/ov-components-adapter.helper.ts

@@ -12,6 +12,27 @@ const enum OpenViduComponentsDataTopic {
 	ROOM_STATUS = 'roomStatus'
 }
 
+interface RecordingSignalPayload {
+	id: string;
+	roomName: string;
+	roomId: string;
+	status: string;
+	filename?: string;
+	startedAt?: number;
+	endedAt?: number;
+	duration?: number;
+	size?: number;
+	location?: string;
+	error?: string;
+}
+
+interface RoomStatusSignalPayload {
+	isRecordingStarted: boolean;
+	recordingList: RecordingSignalPayload[];
+}
+
+export type OpenViduComponentsSignalPayload = RecordingSignalPayload | RoomStatusSignalPayload;
+
 export class OpenViduComponentsAdapterHelper {
 	private constructor() {
 		// Prevent instantiation of this utility class
@@ -29,7 +50,7 @@ export class OpenViduComponentsAdapterHelper {
 
 	static generateRoomStatusSignal(recordingInfo: MeetRecordingInfo[], participantSid?: string) {
 		const isRecordingActive = recordingInfo.some((rec) => rec.status === MeetRecordingStatus.ACTIVE);
-		const payload = {
+		const payload: RoomStatusSignalPayload = {
 			isRecordingStarted: isRecordingActive,
 			recordingList: recordingInfo.map((rec) =>
 				OpenViduComponentsAdapterHelper.parseRecordingInfoToOpenViduComponents(rec)
@@ -46,7 +67,7 @@ export class OpenViduComponentsAdapterHelper {
 		};
 	}
 
-	private static parseRecordingInfoToOpenViduComponents(info: MeetRecordingInfo) {
+	private static parseRecordingInfoToOpenViduComponents(info: MeetRecordingInfo): RecordingSignalPayload {
 		return {
 			id: info.recordingId,
 			roomName: info.roomId,

backend/src/middlewares/participant.middleware.ts

@@ -1,7 +1,12 @@
 import { AuthMode, ParticipantOptions, ParticipantRole, UserRole } from '@typings-ce';
 import { NextFunction, Request, Response } from 'express';
 import { container } from '../config/index.js';
-import { errorInsufficientPermissions, handleError, rejectRequestFromMeetError } from '../models/error.model.js';
+import {
+	errorInsufficientPermissions,
+	errorInvalidParticipantRole,
+	handleError,
+	rejectRequestFromMeetError
+} from '../models/error.model.js';
 import { MeetStorageService, RoomService } from '../services/index.js';
 import { allowAnonymous, tokenAndRoleValidator, withAuth } from './auth.middleware.js';
 
@@ -91,3 +96,22 @@ export const checkParticipantFromSameRoom = async (req: Request, res: Response,
 
 	return next();
 };
+
+export const withValidParticipantRole = async (req: Request, res: Response, next: NextFunction) => {
+	const { role } = req.body;
+
+	if (!role) {
+		const error = errorInvalidParticipantRole();
+		return rejectRequestFromMeetError(res, error);
+	}
+
+	// Validate the role against the ParticipantRole enum
+	const isRoleValid = role === ParticipantRole.MODERATOR || role === ParticipantRole.PUBLISHER;
+
+	if (!isRoleValid) {
+		const error = errorInvalidParticipantRole();
+		return rejectRequestFromMeetError(res, error);
+	}
+
+	return next();
+};

backend/src/routes/meeting.routes.ts

@@ -2,7 +2,7 @@ import bodyParser from 'body-parser';
 import { Router } from 'express';
 import * as meetingCtrl from '../controllers/meeting.controller.js';
 import * as participantCtrl from '../controllers/participant.controller.js';
-import { participantTokenValidator, withAuth, withModeratorPermissions } from '../middlewares/index.js';
+import { participantTokenValidator, withAuth, withModeratorPermissions, withValidParticipantRole, withValidRoomId } from '../middlewares/index.js';
 
 export const internalMeetingRouter = Router();
 internalMeetingRouter.use(bodyParser.urlencoded({ extended: true }));
@@ -13,11 +13,22 @@ internalMeetingRouter.delete(
 	'/:roomId',
 	withAuth(participantTokenValidator),
 	withModeratorPermissions,
+	withValidRoomId,
 	meetingCtrl.endMeeting
 );
 internalMeetingRouter.delete(
 	'/:roomId/participants/:participantName',
 	withAuth(participantTokenValidator),
 	withModeratorPermissions,
+	withValidRoomId,
 	participantCtrl.deleteParticipant
 );
+
+internalMeetingRouter.patch(
+	'/:roomId/participants/:participantName',
+	withAuth(participantTokenValidator),
+	withModeratorPermissions,
+	withValidRoomId,
+	withValidParticipantRole,
+	participantCtrl.changeParticipantRole
+);

backend/src/services/frontend-event.service.ts

@@ -1,9 +1,14 @@
-import { MeetRoom, MeetRecordingInfo } from '@typings-ce';
+import { MeetRoom, MeetRecordingInfo, ParticipantRole } from '@typings-ce';
 import { inject, injectable } from 'inversify';
 import { SendDataOptions } from 'livekit-server-sdk';
-import { OpenViduComponentsAdapterHelper } from '../helpers/index.js';
+import { OpenViduComponentsAdapterHelper, OpenViduComponentsSignalPayload } from '../helpers/index.js';
 import { LiveKitService, LoggerService } from './index.js';
-import { MeetSignalType } from '../typings/ce/event.model.js';
+import {
+	MeetParticipantRoleUpdatedPayload,
+	MeetRoomPreferencesUpdatedPayload,
+	MeetSignalPayload,
+	MeetSignalType
+} from '../typings/ce/event.model.js';
 
 /**
  * Service responsible for all communication with the frontend
@@ -68,9 +73,10 @@ export class FrontendEventService {
 		this.logger.debug(`Sending room preferences updated signal for room ${roomId}`);
 
 		try {
-			const payload = {
+			const payload: MeetRoomPreferencesUpdatedPayload = {
 				roomId,
-				preferences: updatedRoom.preferences
+				preferences: updatedRoom.preferences!,
+				timestamp: Date.now()
 			};
 
 			const options: SendDataOptions = {
@@ -83,13 +89,37 @@ export class FrontendEventService {
 		}
 	}
 
+	async sendParticipantRoleUpdatedSignal(
+		roomId: string,
+		participantName: string,
+		newRole: ParticipantRole,
+		secret: string
+	): Promise<void> {
+		this.logger.debug(
+			`Sending participant role updated signal for participant ${participantName} in room ${roomId}`
+		);
+		const payload: MeetParticipantRoleUpdatedPayload = {
+			participantName,
+			roomId,
+			newRole,
+			secret,
+			timestamp: Date.now()
+		};
+
+		const options: SendDataOptions = {
+			topic: MeetSignalType.MEET_PARTICIPANT_ROLE_UPDATED
+		};
+
+		await this.sendSignal(roomId, payload, options);
+	}
+
 	/**
 	 * Generic method to send signals to the frontend
 	 */
 
 	protected async sendSignal(
 		roomId: string,
-		rawData: Record<string, unknown>,
+		rawData: MeetSignalPayload | OpenViduComponentsSignalPayload,
 		options: SendDataOptions
 	): Promise<void> {
 		this.logger.verbose(`Notifying participants in room ${roomId}: "${options.topic}".`);

backend/src/services/livekit.service.ts

@@ -184,6 +184,29 @@ export class LiveKitService {
 		}
 	}
 
+	/**
+	 * Updates the metadata of a participant in a LiveKit room.
+	 *
+	 * @param roomName - The name of the room where the participant is located
+	 * @param participantName - The name of the participant whose metadata will be updated
+	 * @param metadata - The new metadata to set for the participant
+	 * @returns A Promise that resolves when the metadata has been successfully updated
+	 * @throws An internal error if there is an issue updating the metadata
+	 */
+	async updateParticipantMetadata(
+		roomName: string,
+		participantName: string,
+		metadata: string
+	): Promise<void> {
+		try {
+			await this.roomClient.updateParticipant(roomName, participantName, metadata);
+			this.logger.verbose(`Updated metadata for participant ${participantName} in room ${roomName}`);
+		} catch (error) {
+			this.logger.error(`Error updating metadata for participant ${participantName} in room ${roomName}: ${error}`);
+			throw internalError(`updating metadata for participant '${participantName}' in room '${roomName}'`);
+		}
+	}
+
 	async deleteParticipant(participantName: string, roomName: string): Promise<void> {
 		const participantExists = await this.participantExists(roomName, participantName);
 

backend/src/services/participant.service.ts

@@ -1,8 +1,15 @@
-import { OpenViduMeetPermissions, ParticipantOptions, ParticipantPermissions, ParticipantRole } from '@typings-ce';
+import {
+	MeetTokenMetadata,
+	OpenViduMeetPermissions,
+	ParticipantOptions,
+	ParticipantPermissions,
+	ParticipantRole
+} from '@typings-ce';
 import { inject, injectable } from 'inversify';
 import { ParticipantInfo } from 'livekit-server-sdk';
 import { errorParticipantAlreadyExists, errorParticipantNotFound } from '../models/error.model.js';
-import { LiveKitService, LoggerService, RoomService, TokenService } from './index.js';
+import { FrontendEventService, LiveKitService, LoggerService, RoomService, TokenService } from './index.js';
+import { MeetRoomHelper } from '../helpers/room.helper.js';
 
 @injectable()
 export class ParticipantService {
@@ -10,6 +17,7 @@ export class ParticipantService {
 		@inject(LoggerService) protected logger: LoggerService,
 		@inject(RoomService) protected roomService: RoomService,
 		@inject(LiveKitService) protected livekitService: LiveKitService,
+		@inject(FrontendEventService) protected frontendEventService: FrontendEventService,
 		@inject(TokenService) protected tokenService: TokenService
 	) {}
 
@@ -53,7 +61,7 @@ export class ParticipantService {
 			currentRoles.push({ role, permissions: permissions.openvidu });
 		}
 
-		return this.tokenService.generateParticipantToken(participantOptions, permissions.livekit, currentRoles);
+		return this.tokenService.generateParticipantToken(participantOptions, permissions.livekit, currentRoles, role);
 	}
 
 	async getParticipant(roomId: string, participantName: string): Promise<ParticipantInfo | null> {
@@ -89,7 +97,43 @@ export class ParticipantService {
 		}
 	}
 
-	protected generateModeratorPermissions(roomId: string, addJoinPermission = true): ParticipantPermissions {
+	async changeParticipantRole(roomId: string, participantName: string, newRole: ParticipantRole): Promise<void> {
+		try {
+			const meetRoom = await this.roomService.getMeetRoom(roomId);
+
+			const participant = await this.getParticipant(roomId, participantName);
+
+			const metadata: MeetTokenMetadata = this.parseMetadata(participant!.metadata);
+
+			if (!metadata || typeof metadata !== 'object') {
+				throw new Error(`Invalid metadata for participant ${participantName}`);
+			}
+
+			// TODO: Should we update the roles array as well?
+			metadata.selectedRole = newRole;
+
+			await this.livekitService.updateParticipantMetadata(roomId, participantName, JSON.stringify(metadata));
+
+			const { publisherSecret, moderatorSecret } = MeetRoomHelper.extractSecretsFromRoom(meetRoom);
+
+			const secret = newRole === ParticipantRole.MODERATOR ? moderatorSecret : publisherSecret;
+			await this.frontendEventService.sendParticipantRoleUpdatedSignal(roomId, participantName, newRole, secret);
+		} catch (error) {
+			this.logger.error('Error changing participant role:', error);
+			throw error;
+		}
+	}
+
+	protected parseMetadata(metadata: string): MeetTokenMetadata {
+		try {
+			return JSON.parse(metadata);
+		} catch (error) {
+			this.logger.error('Failed to parse participant metadata:', error);
+			throw new Error('Invalid participant metadata format');
+		}
+	}
+
+	protected generateModeratorPermissions(roomId: string): ParticipantPermissions {
 		return {
 			livekit: {
 				roomJoin: addJoinPermission,

backend/src/services/token.service.ts

@@ -1,5 +1,6 @@
 import {
 	LiveKitPermissions,
+	MeetTokenMetadata,
 	OpenViduMeetPermissions,
 	ParticipantOptions,
 	ParticipantRole,
@@ -42,19 +43,22 @@ export class TokenService {
 	async generateParticipantToken(
 		participantOptions: ParticipantOptions,
 		lkPermissions: LiveKitPermissions,
-		roles: { role: ParticipantRole; permissions: OpenViduMeetPermissions }[]
+		roles: { role: ParticipantRole; permissions: OpenViduMeetPermissions }[],
+		selectedRole: ParticipantRole
 	): Promise<string> {
 		const { roomId, participantName } = participantOptions;
 		this.logger.info(`Generating token for room '${roomId}'`);
 
+		const metadata: MeetTokenMetadata = {
+			livekitUrl: LIVEKIT_URL,
+			roles,
+			selectedRole
+		};
 		const tokenOptions: AccessTokenOptions = {
 			identity: participantName,
 			name: participantName,
 			ttl: INTERNAL_CONFIG.PARTICIPANT_TOKEN_EXPIRATION,
-			metadata: JSON.stringify({
-				livekitUrl: LIVEKIT_URL,
-				roles
-			})
+			metadata: JSON.stringify(metadata)
 		};
 		return await this.generateJwtToken(tokenOptions, lkPermissions as VideoGrant);
 	}