snapshot of https://github.com/RocketChat/Rocket.Chat.git (develop, 2026-09-16; blobs > 131072B omitted)

apps/meteor/server/services/messages/hooks/BeforeSaveMentions.ts

@@ -0,0 +1,87 @@
+import { api, Team, MeteorError } from '@rocket.chat/core-services';
+import type { IMessage, IUser, IRoom } from '@rocket.chat/core-typings';
+import { Subscriptions, Users, Rooms } from '@rocket.chat/models';
+
+import { i18n } from '../../../lib/i18n';
+import { MentionsServer } from '../../../lib/messaging/mentions/Mentions';
+import { settings } from '../../../settings';
+
+class MentionQueries {
+	async getUsers(usernames: string[]): Promise<{ type: 'team' | 'user'; _id: string; username?: string; name?: string }[]> {
+		const uniqueUsernames = [...new Set(usernames)];
+
+		const teams = await Team.listByNames(uniqueUsernames, { projection: { name: 1 } });
+
+		const users = await Users.find<Pick<IUser, '_id' | 'username' | 'name'>>(
+			{ username: { $in: uniqueUsernames } },
+			{ projection: { _id: 1, username: 1, name: 1 } },
+		).toArray();
+
+		const taggedUsers = users.map((user) => ({
+			...user,
+			type: 'user' as const,
+		}));
+
+		if (settings.get<boolean>('Troubleshoot_Disable_Teams_Mention')) {
+			return taggedUsers;
+		}
+
+		const taggedTeams = teams.map((team) => ({
+			...team,
+			type: 'team' as const,
+		}));
+
+		return [...taggedUsers, ...taggedTeams];
+	}
+
+	async getUser(userId: string): Promise<IUser | null> {
+		return Users.findOneById(userId);
+	}
+
+	getTotalChannelMembers(rid: string): Promise<number> {
+		return Subscriptions.countByRoomId(rid);
+	}
+
+	getChannels(channels: string[]): Promise<Pick<IRoom, '_id' | 'name' | 'fname' | 'federated'>[]> {
+		return Rooms.find(
+			{
+				$and: [
+					{
+						$or: [
+							{ $and: [{ $or: [{ federated: { $exists: false } }, { federated: false }], name: { $in: [...new Set(channels)] } }] },
+							{ federated: true, fname: { $in: [...new Set(channels)] } },
+						],
+					},
+				],
+				t: { $in: ['c', 'p'] },
+			},
+			{ projection: { _id: 1, name: 1, fname: 1, federated: 1 } },
+		).toArray();
+	}
+}
+
+const queries = new MentionQueries();
+
+export const mentionServer = new MentionsServer({
+	pattern: () => settings.get<string>('UTF8_User_Names_Validation'),
+	messageMaxAll: () => settings.get<number>('Message_MaxAll'),
+	getUsers: async (usernames: string[]) => queries.getUsers(usernames),
+	getUser: async (userId: string) => queries.getUser(userId),
+	getTotalChannelMembers: (rid: string) => queries.getTotalChannelMembers(rid),
+	getChannels: (channels: string[]) => queries.getChannels(channels),
+	async onMaxRoomMembersExceeded({ sender, rid }: { sender: IMessage['u']; rid: string }): Promise<void> {
+		// Get the language of the user for the error notification.
+		const { language } = (await this.getUser(sender._id)) || {};
+		const msg = i18n.t('Group_mentions_disabled_x_members', { total: this.messageMaxAll(), lng: language });
+
+		void api.broadcast('notify.ephemeralMessage', sender._id, rid, {
+			msg,
+		});
+
+		// Also throw to stop propagation of 'sendMessage'.
+		throw new MeteorError('error-action-not-allowed', msg, {
+			method: 'filterATAllTag',
+			action: msg,
+		});
+	},
+});