Add read counter: add backend for read counter

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 };
+};
+

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,