#151: Mention-Benachrichtigungen über die Glocke

Neuer Notification-Typ mentioned; abgeleitete Tabelle page_mentions
(Migration), vom Collab-Persist transaktional neu geschrieben — der
Diff gegen den Vorzustand wird als pg_notify
(page_mentions_changed) emittiert, nur NEU Erwähnte lösen aus (kein
Spam bei Folge-Saves). Der api-Listener (erweitert um den zweiten
Kanal) ruft NotificationsService.fanoutMentions: Zustellung nur nach
canAccessPage-Recheck, die Autoren (pending contributors) benachrich-
tigen sich nie selbst; Payload wie gehabt mit Actor-Namen. API-seitig
erzeugte Seiten seeden page_mentions aus deriveContent. Glocken-Text
de+en; DB-Test (Leser ja / Outsider nein / Autor nein); kompletter
Loop live verifiziert (Tippen → Persist → NOTIFY → Notification).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0155v2aT8AG1kZDQEZiCLBWC

apps/api/prisma/migrations/20260719232202_page_mentions/migration.sql

@@ -0,0 +1,16 @@
+-- CreateTable
+CREATE TABLE "page_mentions" (
+    "page_id" TEXT NOT NULL,
+    "user_id" TEXT NOT NULL,
+
+    CONSTRAINT "page_mentions_pkey" PRIMARY KEY ("page_id","user_id")
+);
+
+-- CreateIndex
+CREATE INDEX "page_mentions_user_id_idx" ON "page_mentions"("user_id");
+
+-- AddForeignKey
+ALTER TABLE "page_mentions" ADD CONSTRAINT "page_mentions_page_id_fkey" FOREIGN KEY ("page_id") REFERENCES "pages"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "page_mentions" ADD CONSTRAINT "page_mentions_user_id_fkey" FOREIGN KEY ("user_id") REFERENCES "users"("id") ON DELETE CASCADE ON UPDATE CASCADE;

apps/api/prisma/schema.prisma

@@ -52,6 +52,7 @@ model User {
   authTokens      AuthToken[]
   apiTokens       ApiToken[]
   feedTokens      FeedToken[]
+  mentionRows     PageMention[]
   ponds           Pond[]
   pages           Page[]
   attachments     Attachment[]
@@ -282,6 +283,7 @@ model Page {
   attachments         Attachment[]
   versions            PageVersion[]
   pendingContributors PagePendingContributor[]
+  mentionRows         PageMention[]
   labels              PageLabel[]
   outgoingLinks       PageLink[]               @relation("outgoingLinks")
   comments            Comment[]
@@ -349,6 +351,21 @@ model PageVersion {
 /// Collab flushes the current session's contributors here (deduplicated by the
 /// composite key); version creation on either side reads and clears it in the
 /// same transaction as writing the snapshot. Cascades on page purge (ADR 0013).
+/// Derived mention index (issue #151): one row per user currently
+/// mentioned in the page's document. Rewritten on every collab persist;
+/// the diff against the previous rows drives the `mentioned` notifications.
+model PageMention {
+  pageId String @map("page_id")
+  userId String @map("user_id")
+
+  page Page @relation(fields: [pageId], references: [id], onDelete: Cascade)
+  user User @relation(fields: [userId], references: [id], onDelete: Cascade)
+
+  @@id([pageId, userId])
+  @@index([userId])
+  @@map("page_mentions")
+}
+
 model PagePendingContributor {
   pageId String @map("page_id")
   userId String @map("user_id")

apps/api/src/notifications/mentions.e2e.db.test.ts

@@ -0,0 +1,111 @@
+import { INestApplication } from '@nestjs/common';
+import { PrismaClient } from '@prisma/client';
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+
+import { createTestApp } from '../testing/test-app';
+import { createTestPrisma, hasTestDb, uniqueSuffix } from '../testing/test-db';
+import { NotificationsService } from './notifications.service';
+
+/**
+ * Mention notifications (issue #151): newly mentioned users get a
+ * `mentioned` notification — but only with read access (no leak), and the
+ * mention's author (a pending contributor) never notifies themselves.
+ */
+describe.skipIf(!hasTestDb)('mention notifications (e2e, issue #151)', () => {
+  let app: INestApplication;
+  let prisma: PrismaClient;
+  const suffix = uniqueSuffix();
+
+  let authorId: string;
+  let readerId: string;
+  let outsiderId: string;
+  let pageId: string;
+
+  beforeAll(async () => {
+    prisma = createTestPrisma();
+    app = await createTestApp();
+
+    const mkUser = async (handle: string) =>
+      (
+        await prisma.user.create({
+          data: {
+            username: `mention-${handle}-${suffix}`,
+            email: `mention-${handle}-${suffix}@example.test`,
+            displayName: `Mention ${handle}`,
+            status: 'ACTIVE',
+          },
+        })
+      ).id;
+    authorId = await mkUser('author');
+    readerId = await mkUser('reader');
+    outsiderId = await mkUser('outsider');
+
+    const pond = await prisma.pond.create({
+      data: {
+        slug: `mention-pond-${suffix}`,
+        name: 'Mention Pond',
+        type: 'SHARED',
+        ownerId: authorId,
+      },
+    });
+    const page = await prisma.page.create({
+      data: {
+        pondId: pond.id,
+        slug: `notes-${suffix}`,
+        title: 'Notes',
+        createdBy: authorId,
+        sortKey: 'a0',
+        ydocState: new Uint8Array(),
+      },
+    });
+    pageId = page.id;
+    for (const [userId, role] of [
+      [authorId, 'EDITOR'],
+      [readerId, 'READER'],
+    ] as const) {
+      await prisma.roleGrant.create({
+        data: {
+          pondId: pond.id,
+          subjectType: 'USER',
+          subjectId: userId,
+          role,
+          scopeType: 'POND',
+          scopeId: null,
+          effect: 'ALLOW',
+          createdBy: authorId,
+        },
+      });
+    }
+    // The author edited last — pending contributor, i.e. the acting user.
+    await prisma.pagePendingContributor.create({ data: { pageId, userId: authorId } });
+  });
+
+  afterAll(async () => {
+    await prisma.notification.deleteMany({
+      where: { userId: { in: [authorId, readerId, outsiderId] } },
+    });
+    await prisma.pagePendingContributor.deleteMany({ where: { pageId } });
+    await prisma.roleGrant.deleteMany({ where: { pond: { ownerId: authorId } } });
+    await prisma.page.deleteMany({ where: { pond: { ownerId: authorId } } });
+    await prisma.pond.deleteMany({ where: { ownerId: authorId } });
+    await prisma.user.deleteMany({ where: { id: { in: [authorId, readerId, outsiderId] } } });
+    await prisma.$disconnect();
+    await app.close();
+  });
+
+  it('notifies mentioned readers, skips outsiders and the author', async () => {
+    await app.get(NotificationsService).fanoutMentions(pageId, [readerId, outsiderId, authorId]);
+
+    const readerRows = await prisma.notification.findMany({ where: { userId: readerId } });
+    expect(readerRows).toHaveLength(1);
+    expect(readerRows[0]!.type).toBe('mentioned');
+    expect(readerRows[0]!.payload).toMatchObject({
+      pageTitle: 'Notes',
+      actorNames: ['Mention author'],
+    });
+
+    // No read access → nothing; the author never notifies themselves.
+    expect(await prisma.notification.count({ where: { userId: outsiderId } })).toBe(0);
+    expect(await prisma.notification.count({ where: { userId: authorId } })).toBe(0);
+  });
+});

apps/api/src/notifications/notifications.service.ts

@@ -94,6 +94,64 @@ export class NotificationsService {
     }
   }
 
+  /**
+   * Notifies newly mentioned users (issue #151). Independent of the watch
+   * table — a mention addresses the person directly — but with the same
+   * delivery-time read-permission re-check: whoever may not read the page
+   * gets nothing (no leak). The mention's authors (the page's pending
+   * contributors at persist time) never notify themselves.
+   */
+  async fanoutMentions(pageId: string, mentionedUserIds: string[]): Promise<void> {
+    try {
+      const page = await this.prisma.page.findFirst({
+        where: { id: pageId, deletedAt: null },
+        select: { id: true, pondId: true, title: true, slug: true },
+      });
+      if (!page) return;
+      const pond = await this.prisma.pond.findFirst({
+        where: { id: page.pondId, deletedAt: null },
+        select: { name: true, slug: true },
+      });
+      if (!pond) return;
+
+      const contributors = await this.prisma.pagePendingContributor.findMany({
+        where: { pageId },
+        select: { userId: true },
+      });
+      const actorIds = contributors.map((row) => row.userId);
+      const actors = actorIds.length
+        ? await this.prisma.user.findMany({
+            where: { id: { in: actorIds } },
+            select: { displayName: true },
+          })
+        : [];
+      const payload: NotificationPayload = {
+        pageId: page.id,
+        pageTitle: page.title,
+        pageSlug: page.slug,
+        pondSlug: pond.slug,
+        pondName: pond.name,
+        actorNames: actors.slice(0, 3).map((actor) => actor.displayName),
+      };
+
+      const targets = await this.prisma.user.findMany({
+        where: { id: { in: mentionedUserIds.filter((id) => !actorIds.includes(id)) } },
+      });
+      for (const target of targets) {
+        if (!(await this.permissions.canAccessPage(target, page, 'read'))) continue;
+        await this.prisma.notification.create({
+          data: {
+            userId: target.id,
+            type: 'mentioned',
+            payload: payload as unknown as Prisma.InputJsonObject,
+          },
+        });
+      }
+    } catch (error) {
+      this.logger.warn({ pageId, err: error }, 'mention fan-out failed');
+    }
+  }
+
   async list(user: User, page: number): Promise<NotificationListView> {
     const where = { userId: user.id };
     const [total, unreadCount] = [

apps/api/src/notifications/version-event-listener.service.ts

@@ -1,5 +1,10 @@
 import { Injectable, OnModuleDestroy, OnModuleInit } from '@nestjs/common';
-import { PAGE_VERSION_CREATED_CHANNEL, type PageVersionCreatedEvent } from '@dorfteich/shared';
+import {
+  PAGE_MENTIONS_CHANGED_CHANNEL,
+  PAGE_VERSION_CREATED_CHANNEL,
+  type PageMentionsChangedEvent,
+  type PageVersionCreatedEvent,
+} from '@dorfteich/shared';
 import { PinoLogger } from 'nestjs-pino';
 import { Client } from 'pg';
 
@@ -49,12 +54,17 @@ export class VersionEventListener implements OnModuleInit, OnModuleDestroy {
     client.on('error', () => this.scheduleReconnect());
     client.on('end', () => this.scheduleReconnect());
     client.on('notification', (message) => {
-      if (message.channel !== PAGE_VERSION_CREATED_CHANNEL || !message.payload) return;
+      if (!message.payload) return;
-      void this.handle(message.payload);
+      if (message.channel === PAGE_VERSION_CREATED_CHANNEL) void this.handle(message.payload);
+      // Newly added mentions from a collab persist (issue #151).
+      if (message.channel === PAGE_MENTIONS_CHANGED_CHANNEL) {
+        void this.handleMentions(message.payload);
+      }
     });
     try {
       await client.connect();
       await client.query(`LISTEN ${PAGE_VERSION_CREATED_CHANNEL}`);
+      await client.query(`LISTEN ${PAGE_MENTIONS_CHANGED_CHANNEL}`);
       this.logger.info({}, 'listening for collab version events');
     } catch (error) {
       this.logger.warn({ err: error }, 'version-event listener could not connect');
@@ -79,4 +89,16 @@ export class VersionEventListener implements OnModuleInit, OnModuleDestroy {
       this.logger.warn({ err: error }, 'ignoring malformed version event');
     }
   }
+
+  private async handleMentions(payload: string): Promise<void> {
+    try {
+      const event = JSON.parse(payload) as PageMentionsChangedEvent;
+      if (!event.pageId || !Array.isArray(event.addedUserIds) || event.addedUserIds.length === 0) {
+        return;
+      }
+      await this.notifications.fanoutMentions(event.pageId, event.addedUserIds);
+    } catch (error) {
+      this.logger.warn({ err: error }, 'ignoring malformed mentions event');
+    }
+  }
 }

apps/api/src/pages/yjs-content.ts

@@ -5,6 +5,7 @@ import {
   editorSchema,
   extractOutline,
   OutlineEntry,
+  extractMentionUserIds,
   extractWikilinkSlugs,
 } from '@dorfteich/shared';
 import { Node } from 'prosemirror-model';
@@ -93,6 +94,9 @@ export interface DerivedPageContent {
    * api (imports, phantom-create) seed their `page_links` rows from this —
    * collab, the content writer, rewrites them on every later save. */
   wikilinkSlugs: string[];
+  /** Resolved user ids of every `@mention` (issue #151) — api-created pages
+   * seed their `page_mentions` rows from this; collab rewrites on save. */
+  mentionUserIds: string[];
 }
 
 function imageFileIdsOf(doc: Node): string[] {
@@ -119,5 +123,6 @@ export function deriveContent(state: Uint8Array): DerivedPageContent {
     outline: extractOutline(doc),
     imageFileIds: imageFileIdsOf(doc),
     wikilinkSlugs: extractWikilinkSlugs(doc),
+    mentionUserIds: extractMentionUserIds(doc),
   };
 }

apps/collab/src/persistence.ts

@@ -1,4 +1,8 @@
-import { MAX_PAGE_DOCUMENT_BYTES, normalizeForSearch } from '@dorfteich/shared';
+import {
+  MAX_PAGE_DOCUMENT_BYTES,
+  PAGE_MENTIONS_CHANGED_CHANNEL,
+  normalizeForSearch,
+} from '@dorfteich/shared';
 import type { Pool } from 'pg';
 import * as Y from 'yjs';
 
@@ -203,6 +207,31 @@ export class PostgresPagePersistence implements PagePersistence {
         );
       }
 
+      // Rewrite the mention index (issue #151); newly added user ids become a
+      // NOTIFY the api turns into `mentioned` notifications. Inside the
+      // transaction on purpose — pg_notify only fires on COMMIT.
+      const previousMentions = await client.query<{ user_id: string }>(
+        'SELECT user_id FROM page_mentions WHERE page_id = $1',
+        [pageId],
+      );
+      await client.query('DELETE FROM page_mentions WHERE page_id = $1', [pageId]);
+      if (derived.mentionUserIds.length > 0) {
+        await client.query(
+          `INSERT INTO page_mentions (page_id, user_id)
+           SELECT $1, u.id FROM unnest($2::text[]) AS m(user_id)
+           JOIN users u ON u.id = m.user_id`,
+          [pageId, derived.mentionUserIds],
+        );
+      }
+      const known = new Set(previousMentions.rows.map((row) => row.user_id));
+      const added = derived.mentionUserIds.filter((id) => !known.has(id));
+      if (added.length > 0) {
+        await client.query('SELECT pg_notify($1, $2)', [
+          PAGE_MENTIONS_CHANGED_CHANNEL,
+          JSON.stringify({ pageId, addedUserIds: added }),
+        ]);
+      }
+
       await client.query('COMMIT');
       this.lastStoredVector.set(pageId, nextVector);
       return { outcome: 'stored', bytes: full.byteLength, durationMs: durationOf(), merged };

apps/collab/src/yjs-content.ts

@@ -4,6 +4,7 @@ import {
   docToPlainText,
   editorSchema,
   extractOutline,
+  extractMentionUserIds,
   extractWikilinkSlugs,
   type OutlineEntry,
 } from '@dorfteich/shared';
@@ -44,6 +45,9 @@ export interface DerivedPageContent {
   /** Distinct target slugs of every `[[wikilink]]`, for the `page_links`
    * index (issue #47). */
   wikilinkSlugs: string[];
+  /** Distinct resolved user ids of every `@mention`, for the
+   * `page_mentions` index and the mention notifications (issue #151). */
+  mentionUserIds: string[];
 }
 
 function imageFileIdsOf(doc: Node): string[] {
@@ -70,5 +74,6 @@ export function deriveContentFromDoc(ydoc: Y.Doc): DerivedPageContent {
     outline: extractOutline(doc),
     imageFileIds: imageFileIdsOf(doc),
     wikilinkSlugs: extractWikilinkSlugs(doc),
+    mentionUserIds: extractMentionUserIds(doc),
   };
 }

packages/shared/i18n/de/notifications.json

@@ -5,7 +5,8 @@
   "someone": "Jemand",
   "types": {
     "page_changed": "{{actor}} hat „{{page}}“ in {{pond}} geändert",
-    "comment_added": "{{actor}} hat „{{page}}“ in {{pond}} kommentiert"
+    "comment_added": "{{actor}} hat „{{page}}“ in {{pond}} kommentiert",
+    "mentioned": "{{actor}} hat dich auf „{{page}}“ in {{pond}} erwähnt"
   },
   "digest": {
     "label": "E-Mail-Digest",

packages/shared/i18n/en/notifications.json

@@ -5,7 +5,8 @@
   "someone": "Someone",
   "types": {
     "page_changed": "{{actor}} changed “{{page}}” in {{pond}}",
-    "comment_added": "{{actor}} commented on “{{page}}” in {{pond}}"
+    "comment_added": "{{actor}} commented on “{{page}}” in {{pond}}",
+    "mentioned": "{{actor}} mentioned you on “{{page}}” in {{pond}}"
   },
   "digest": {
     "label": "E-mail digest",

packages/shared/src/collab-token.ts

@@ -56,6 +56,21 @@ export interface PageVersionCreatedEvent {
  */
 export const TASK_TOGGLE_CHANNEL = 'task_toggle';
 
+/**
+ * PostgreSQL `NOTIFY` channel over which the collab server announces that a
+ * persist added new user mentions to a page (issue #151). The api listens
+ * and creates the `mentioned` notifications — permission-checked there.
+ * Payload is a JSON {@link PageMentionsChangedEvent}.
+ */
+export const PAGE_MENTIONS_CHANGED_CHANNEL = 'page_mentions_changed';
+
+/** JSON payload carried on {@link PAGE_MENTIONS_CHANGED_CHANNEL}. */
+export interface PageMentionsChangedEvent {
+  pageId: string;
+  /** Users newly mentioned by this persist (diff against the stored rows). */
+  addedUserIds: string[];
+}
+
 /** JSON payload carried on {@link TASK_TOGGLE_CHANNEL}. */
 export interface TaskToggleRequest {
   pageId: string;

packages/shared/src/notifications.ts

@@ -7,7 +7,7 @@ import { z } from 'zod';
  * permission at delivery time.
  */
 
-export const NOTIFICATION_TYPES = ['page_changed', 'comment_added'] as const;
+export const NOTIFICATION_TYPES = ['page_changed', 'comment_added', 'mentioned'] as const;
 export type NotificationType = (typeof NOTIFICATION_TYPES)[number];
 
 export interface NotificationPayload {