Iteration 2: expose read counts as API endpoint

apps/meteor/app/api/server/v1/chat.ts

@@ -29,6 +29,7 @@ import {
 	isChatSyncThreadMessagesProps,
 	isChatGetStarredMessagesProps,
 	isChatGetDiscussionsProps,
+	isChatGetMessageReadCountProps,
 	validateBadRequestErrorResponse,
 	validateUnauthorizedErrorResponse,
 } from '@rocket.chat/rest-typings';
@@ -48,6 +49,7 @@ import { processWebhookMessage } from '../../../lib/server/functions/processWebh
 import { getSingleMessage } from '../../../lib/server/methods/getSingleMessage';
 import { executeSendMessage } from '../../../lib/server/methods/sendMessage';
 import { executeUpdateMessage } from '../../../lib/server/methods/updateMessage';
+import { getMessageReadCount as getMessageReadCountHelper } from '../../../read-counter/server/getMessageReadCount';
 import { applyAirGappedRestrictionsValidation } from '../../../license/server/airGappedRestrictionsWrapper';
 import { pinMessage, unpinMessage } from '../../../message-pin/server/pinMessage';
 import { starMessage } from '../../../message-star/server/starMessage';
@@ -174,6 +176,37 @@ API.v1.addRoute(
 	},
 );
 
+API.v1.addRoute(
+	'chat.getMessageReadCount',
+	{
+		authRequired: true,
+		validateParams: isChatGetMessageReadCountProps,
+	},
+	{
+		async get() {
+			const { messageId } = this.queryParams;
+
+			const message = await Messages.findOneById(messageId, { projection: { rid: 1 } });
+
+			if (!message) {
+				return API.v1.failure('The required "messageId" param is missing or invalid.');
+			}
+
+			if (!(await canAccessRoomIdAsync(message.rid, this.userId))) {
+				throw new Meteor.Error('error-not-allowed', 'Not allowed');
+			}
+
+			const result = await getMessageReadCountHelper(messageId, this.userId);
+
+			if (!result) {
+				return API.v1.failure();
+			}
+
+			return API.v1.success(result);
+		},
+	},
+);
+
 type ChatPinMessage = {
 	messageId: IMessage['_id'];
 };

apps/meteor/app/lib/server/functions/loadMessageHistory.ts

@@ -5,6 +5,8 @@ import type { FindOptions } from 'mongodb';
 import { settings } from '../../../settings/server/cached';
 import { normalizeMessagesForUser } from '../../../utils/server/lib/normalizeMessagesForUser';
 import { getHiddenSystemMessages } from '../lib/getHiddenSystemMessages';
+import { getMessageReadCount } from '../../../read-counter/server/getMessageReadCount';
+import { SystemLogger } from '../../../../server/lib/logger/system';
 
 export async function loadMessageHistory({
 	userId,
@@ -52,6 +54,20 @@ export async function loadMessageHistory({
 			).toArray()
 		: await Messages.findVisibleByRoomIdNotContainingTypes(rid, hiddenMessageTypes, options, showThreadMessages).toArray();
 	const messages = await normalizeMessagesForUser(records, userId);
+
+	if (messages[0]?._id && userId) {
+		const readCountResult = await getMessageReadCount(messages[0]._id, userId);
+
+		if (readCountResult) {
+			SystemLogger.info({
+				msg: '[read-count demo] newest message readCount',
+				rid,
+				mid: messages[0]._id,
+				readCount: readCountResult.readCount,
+				uid: userId,
+			});
+		}
+	}
 	let unreadNotLoaded = 0;
 	let firstUnread;
 

apps/meteor/app/read-counter/server/getMessageReadCount.ts

@@ -0,0 +1,45 @@
+import type { IMessage, IRoom, IUser } from '@rocket.chat/core-typings';
+import { Authorization } from '@rocket.chat/core-services';
+import { Messages, Rooms, Subscriptions } from '@rocket.chat/models';
+
+export const getMessageReadCount = async (
+	messageId: IMessage['_id'],
+	userId: IUser['_id'],
+): Promise<{ readCount: number } | null> => {
+	const message = await Messages.findOneById(messageId, {
+		projection: { _id: 1, rid: 1, ts: 1, 'u._id': 1 },
+	});
+
+	if (!message) {
+		return null;
+	}
+
+	const room = await Rooms.findOneById(message.rid as IRoom['_id'], {
+		projection: { _id: 1, t: 1 },
+	});
+
+	if (!room) {
+		return null;
+	}
+
+	// Exclude DMs from read counter
+	if (room.t === 'd') {
+		return null;
+	}
+
+	// Ensure the requesting user can access the room
+	if (!(await Authorization.canReadRoom(room, { _id: userId }))) {
+		return null;
+	}
+
+	if (!message.ts) {
+		return { readCount: 0 };
+	}
+
+	const excludeUserId = message.u?._id;
+
+	const readCount = await Subscriptions.countReadersByRoomIdAndMessageTs(message.rid, message.ts, excludeUserId);
+
+	return { readCount };
+};
+

apps/meteor/server/methods/getMessageReadCount.ts

@@ -0,0 +1,27 @@
+import type { IMessage } from '@rocket.chat/core-typings';
+import type { ServerMethods } from '@rocket.chat/ddp-client';
+import { check } from 'meteor/check';
+import { Meteor } from 'meteor/meteor';
+
+import { getMessageReadCount as getMessageReadCountHelper } from '../../app/read-counter/server/getMessageReadCount';
+
+declare module '@rocket.chat/ddp-client' {
+	// eslint-disable-next-line @typescript-eslint/naming-convention
+	interface ServerMethods {
+		getMessageReadCount(options: { messageId: IMessage['_id'] }): { readCount: number } | null;
+	}
+}
+
+Meteor.methods<ServerMethods>({
+	async getMessageReadCount({ messageId }) {
+		check(messageId, String);
+
+		const uid = Meteor.userId();
+		if (!uid) {
+			throw new Meteor.Error('error-invalid-user', 'Invalid user', { method: 'getMessageReadCount' });
+		}
+
+		return getMessageReadCountHelper(messageId, uid);
+	},
+});
+

apps/meteor/server/methods/index.ts

@@ -13,6 +13,7 @@ import './createDirectMessage';
 import './deleteFileMessage';
 import './deleteUser';
 import './getAvatarSuggestion';
+import './getMessageReadCount';
 import './getRoomById';
 import './getRoomIdByNameOrId';
 import './getRoomNameById';

packages/model-typings/src/models/ISubscriptionsModel.ts

@@ -22,6 +22,8 @@ import type { DocumentWithProjection } from '../types/DocumentWithProjection';
 export interface ISubscriptionsModel extends IBaseModel<ISubscription> {
 	getBadgeCount(uid: string): Promise<number>;
 
+	countReadersByRoomIdAndMessageTs(rid: string, messageTs: Date, excludeUserId?: string): Promise<number>;
+
 	findOneByRoomIdAndUserId(rid: string, uid: string, options?: FindOptions<ISubscription>): Promise<ISubscription | null>;
 
 	findByUserIdAndRoomIds(userId: string, roomIds: Array<string>, options?: FindOptions<ISubscription>): FindCursor<ISubscription>;

packages/models/src/models/Subscriptions.ts

@@ -86,6 +86,20 @@
 		return result?.total || 0;
 	}
 
+	countReadersByRoomIdAndMessageTs(rid: string, messageTs: Date, excludeUserId?: string): Promise<number> {
+		const query: Filter<ISubscription> = {
+			rid,
+			archived: { $ne: true },
+			ls: { $gte: messageTs },
+			'u._id': {
+				...(excludeUserId ? { $ne: excludeUserId } : {}),
+				$exists: true,
+			},
+		};
+
+		return this.countDocuments(query);
+	}
+
 	findOneByRoomIdAndUserId(rid: string, uid: string, options: FindOptions<ISubscription> = {}): Promise<ISubscription | null> {
 		const query = {
 			rid,

packages/rest-typings/src/v1/chat.ts

@@ -574,6 +574,23 @@ const ChatGetMessageReadReceiptsSchema = {
 
 export const isChatGetMessageReadReceiptsProps = ajv.compile<ChatGetMessageReadReceipts>(ChatGetMessageReadReceiptsSchema);
 
+type ChatGetMessageReadCount = {
+	messageId: IMessage['_id'];
+};
+
+const ChatGetMessageReadCountSchema = {
+	type: 'object',
+	properties: {
+		messageId: {
+			type: 'string',
+		},
+	},
+	required: ['messageId'],
+	additionalProperties: false,
+};
+
+export const isChatGetMessageReadCountProps = ajv.compile<ChatGetMessageReadCount>(ChatGetMessageReadCountSchema);
+
 type GetStarredMessages = {
 	roomId: IRoom['_id'];
 	count?: number;
@@ -1054,6 +1071,9 @@ export type ChatEndpoints = {
 	'/v1/chat.getMessageReadReceipts': {
 		GET: (params: ChatGetMessageReadReceipts) => { receipts: IReadReceiptWithUser[] };
 	};
+	'/v1/chat.getMessageReadCount': {
+		GET: (params: ChatGetMessageReadCount) => { readCount: number };
+	};
 	'/v1/chat.getStarredMessages': {
 		GET: (params: GetStarredMessages) => {
 			messages: IMessage[];