Add capability-scoped plugin API endpoints (#74, read surface)

Viewer-scoped data API behind /api/v1/plugin/, backing the SDK's
readCurrentPage and readPond capabilities:
- api: PluginApiController with GET plugin/ponds/:id/pages (listPages),
  plugin/pages/:id/{outline,content,meta}. Each reuses the existing
  @RequiresPondRole/@RequiresPagePermission guards and PagesService — no
  parallel permission logic — so a plugin sees exactly what its viewer
  could. New PagesService.outline/meta read the content cache.
- web: host-capabilities builds the host implementations from a per-
  surface context (the host holds the current page/pond ids; a plugin can
  only ask about "the current page" or "this pond"). Wired into the
  sandbox host and PluginFrame; ui.openPage/toast route to host callbacks.
- shared: PluginPageSummary/Meta/Content response types.
- tests: api db test proves a label-restricted reader gets a filtered
  listPages and 404s on the hidden page, non-members are hidden (404),
  anonymous is rejected (401); web unit test pins the endpoint mapping,
  id-encoding, and missing-context rejection.

readBlock/blockData land with the plugin_block node in #76 (block
addressing does not exist in the schema yet).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EwZ4jR4KFAPvpjWevfUGX1

apps/api/src/pages/pages.module.ts

@@ -5,10 +5,11 @@ import { SearchModule } from '../search/search.module';
 
 import { PagesController } from './pages.controller';
 import { PagesService } from './pages.service';
+import { PluginApiController } from './plugin-api.controller';
 
 @Module({
   imports: [PondsModule, SearchModule],
-  controllers: [PagesController],
+  controllers: [PagesController, PluginApiController],
   providers: [PagesService],
   exports: [PagesService],
 })

apps/api/src/pages/pages.service.ts

@@ -2,6 +2,7 @@ import { ConflictException, Injectable, NotFoundException } from '@nestjs/common
 import {
   CollabTokenResponse,
   CreatePageInput,
+  OutlineEntry,
   PageListItemView,
   PageStateView,
   PageView,
@@ -352,6 +353,20 @@ export class PagesService {
     return { slug: page.slug, markdown: cache?.markdown ?? '' };
   }
 
+  /** The page's heading outline from the content cache (plugin API #74).
+   * Permission is enforced by the caller's page-read guard. */
+  async outline(id: string): Promise<OutlineEntry[]> {
+    const page = await this.findLivePage(id);
+    const cache = await this.prisma.pageContentCache.findUnique({ where: { pageId: page.id } });
+    return (cache?.outline as unknown as OutlineEntry[] | undefined) ?? [];
+  }
+
+  /** Minimal page metadata for the plugin API (#74): id, title, pond, slug. */
+  async meta(id: string): Promise<{ id: string; title: string; pondId: string; slug: string }> {
+    const page = await this.findLivePage(id);
+    return { id: page.id, title: page.title, pondId: page.pondId, slug: page.slug };
+  }
+
   async softDelete(user: User, id: string): Promise<void> {
     const page = await this.findLivePage(id);
     await this.prisma.page.update({

apps/api/src/pages/plugin-api.controller.ts

@@ -0,0 +1,58 @@
+import { Controller, Get, Param, Req } from '@nestjs/common';
+import type { OutlineEntry } from '@dorfteich/shared';
+import type { PluginPageContent, PluginPageMeta, PluginPageSummary } from '@dorfteich/shared';
+
+import { AuthedRequest } from '../auth/auth.guard';
+import { RequiresPagePermission, RequiresPondRole } from '../permissions/permission.decorators';
+
+import { PagesService } from './pages.service';
+
+/**
+ * Viewer-scoped plugin data API (ADR 0008, issue #74). These endpoints back
+ * the plugin SDK's `readCurrentPage` and `readPond` capabilities: the host
+ * bridge calls them with the viewing user's session, and each reuses the same
+ * page/pond permission guards as the rest of the app — a plugin can never read
+ * more than the person looking at it (no parallel permission logic). The
+ * `readBlock`/`blockData` capabilities land with the `plugin_block` node in
+ * issue #76, where block addressing exists.
+ */
+@Controller('plugin')
+export class PluginApiController {
+  constructor(private readonly pages: PagesService) {}
+
+  /** `readPond.listPages` — the pages of a pond the viewer may read. */
+  @Get('ponds/:pondId/pages')
+  @RequiresPondRole('reader', { idParam: 'pondId' }) // the service filters per page
+  async listPages(
+    @Param('pondId') pondId: string,
+    @Req() request: AuthedRequest,
+  ): Promise<PluginPageSummary[]> {
+    const pages = await this.pages.list(request.user!, pondId);
+    return pages.map((page) => ({ id: page.id, title: page.title, slug: page.slug }));
+  }
+
+  /** `readCurrentPage.getOutline` / `readPond.getPageOutline`. */
+  @Get('pages/:pageId/outline')
+  @RequiresPagePermission('read', { idParam: 'pageId' })
+  outline(@Param('pageId') pageId: string): Promise<OutlineEntry[]> {
+    return this.pages.outline(pageId);
+  }
+
+  /** `readCurrentPage.getContent` / `readPond.getPageContent` (Markdown). */
+  @Get('pages/:pageId/content')
+  @RequiresPagePermission('read', { idParam: 'pageId' })
+  async content(
+    @Param('pageId') pageId: string,
+    @Req() request: AuthedRequest,
+  ): Promise<PluginPageContent> {
+    const { markdown } = await this.pages.exportMarkdown(request.user!, pageId);
+    return { markdown };
+  }
+
+  /** `readCurrentPage.getMeta`. */
+  @Get('pages/:pageId/meta')
+  @RequiresPagePermission('read', { idParam: 'pageId' })
+  meta(@Param('pageId') pageId: string): Promise<PluginPageMeta> {
+    return this.pages.meta(pageId);
+  }
+}

apps/api/src/pages/plugin-api.e2e.db.test.ts

@@ -0,0 +1,202 @@
+import { INestApplication } from '@nestjs/common';
+import { PrismaClient } from '@prisma/client';
+import request from 'supertest';
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+
+import { PondsService } from '../ponds/ponds.service';
+import { createTestApp, sessionCookieOf } from '../testing/test-app';
+import { createTestPrisma, hasTestDb, uniqueSuffix } from '../testing/test-db';
+import { UsersService } from '../users/users.service';
+
+/**
+ * Viewer-scoped plugin API (issue #74). The `/plugin/*` endpoints reuse the
+ * same page/pond guards as the rest of the app, so a plugin sees exactly what
+ * its viewer could: a label-restricted reader gets a filtered `listPages` and
+ * a 404 on the page they cannot read; a non-member is refused outright.
+ */
+describe.skipIf(!hasTestDb)('plugin API (e2e, issue #74)', () => {
+  let app: INestApplication;
+  let prisma: PrismaClient;
+  const suffix = uniqueSuffix();
+  const password = 'plugins lesen nur was der nutzer darf 1';
+
+  const userIds: Record<string, string> = {};
+  const cookies: Record<string, string> = {};
+  let pondId: string;
+  let openPageId: string;
+  let secretPageId: string;
+
+  const api = () => request(app.getHttpServer());
+
+  async function makeUser(handle: string): Promise<void> {
+    const users = app.get(UsersService);
+    const username = `plugapi-${handle}-${suffix}`;
+    const user = await users.createUser({
+      username,
+      email: `${username}@example.org`,
+      displayName: `PlugApi ${handle}`,
+      password,
+      locale: 'en',
+    });
+    userIds[handle] = user.id;
+    await users.markEmailVerified(user.id);
+    const res = await api()
+      .post('/api/v1/auth/login')
+      .send({ usernameOrEmail: username, password })
+      .expect(200);
+    cookies[handle] = sessionCookieOf(res);
+  }
+
+  beforeAll(async () => {
+    prisma = createTestPrisma();
+    await prisma.rateLimit.deleteMany({});
+    app = await createTestApp();
+
+    for (const handle of ['owner', 'reader', 'foreign']) await makeUser(handle);
+    await app
+      .get(PondsService)
+      .ensurePersonalPond(await prisma.user.findUniqueOrThrow({ where: { id: userIds.owner! } }));
+    await prisma.quotaOverride.create({
+      data: {
+        subjectType: 'USER',
+        subjectId: userIds.owner!,
+        quotaKey: 'additional_ponds',
+        value: 10,
+      },
+    });
+
+    const pond = await api()
+      .post('/api/v1/ponds')
+      .set('Cookie', cookies.owner!)
+      .send({ name: `PlugApi Pond ${suffix}` })
+      .expect(201);
+    pondId = pond.body.id;
+
+    const open = await api()
+      .post(`/api/v1/ponds/${pondId}/pages`)
+      .set('Cookie', cookies.owner!)
+      .send({ title: 'Open Page' })
+      .expect(201);
+    openPageId = open.body.id;
+    const secret = await api()
+      .post(`/api/v1/ponds/${pondId}/pages`)
+      .set('Cookie', cookies.owner!)
+      .send({ title: 'Secret Page' })
+      .expect(201);
+    secretPageId = secret.body.id;
+
+    // The reader may see the pond, but a label-deny hides the secret page.
+    await api()
+      .post(`/api/v1/ponds/${pondId}/grants`)
+      .set('Cookie', cookies.owner!)
+      .send({
+        subjectType: 'user',
+        subjectId: userIds.reader!,
+        role: 'reader',
+        scopeType: 'pond',
+        effect: 'allow',
+      })
+      .expect(201);
+    const label = await api()
+      .post(`/api/v1/ponds/${pondId}/labels`)
+      .set('Cookie', cookies.owner!)
+      .send({ name: `secret-${suffix}` })
+      .expect(201);
+    await api()
+      .post(`/api/v1/pages/${secretPageId}/labels`)
+      .set('Cookie', cookies.owner!)
+      .send({ labelId: label.body.id })
+      .expect(201);
+    await api()
+      .post(`/api/v1/ponds/${pondId}/grants`)
+      .set('Cookie', cookies.owner!)
+      .send({
+        subjectType: 'user',
+        subjectId: userIds.reader!,
+        role: 'reader',
+        scopeType: 'label',
+        scopeId: label.body.id,
+        effect: 'deny',
+      })
+      .expect(201);
+  });
+
+  afterAll(async () => {
+    await prisma.roleGrant.deleteMany({ where: { pondId } });
+    await prisma.pageLabel.deleteMany({ where: { page: { pondId } } });
+    await prisma.label.deleteMany({ where: { pondId } });
+    await prisma.pageContentCache.deleteMany({ where: { page: { pondId } } });
+    await prisma.pageUpdate.deleteMany({ where: { page: { pondId } } });
+    await prisma.page.deleteMany({ where: { pondId } });
+    await prisma.pond.deleteMany({ where: { id: pondId } });
+    const ids = Object.values(userIds);
+    await prisma.roleGrant.deleteMany({ where: { pond: { ownerId: { in: ids } } } });
+    await prisma.pond.deleteMany({ where: { ownerId: { in: ids } } });
+    await prisma.quotaOverride.deleteMany({ where: { subjectId: { in: ids } } });
+    await prisma.user.deleteMany({ where: { id: { in: ids } } });
+    await prisma.$disconnect();
+    await app.close();
+  });
+
+  it('lists all pages for a full reader (the owner)', async () => {
+    const res = await api()
+      .get(`/api/v1/plugin/ponds/${pondId}/pages`)
+      .set('Cookie', cookies.owner!)
+      .expect(200);
+    expect(res.body.map((p: { id: string }) => p.id).sort()).toEqual(
+      [openPageId, secretPageId].sort(),
+    );
+    expect(res.body[0]).toMatchObject({ title: expect.any(String), slug: expect.any(String) });
+  });
+
+  it('filters listPages for a label-restricted reader and 404s the hidden page', async () => {
+    const list = await api()
+      .get(`/api/v1/plugin/ponds/${pondId}/pages`)
+      .set('Cookie', cookies.reader!)
+      .expect(200);
+    const ids = list.body.map((p: { id: string }) => p.id);
+    expect(ids).toContain(openPageId);
+    expect(ids).not.toContain(secretPageId);
+
+    // The readable page's content/outline/meta are served…
+    await api()
+      .get(`/api/v1/plugin/pages/${openPageId}/content`)
+      .set('Cookie', cookies.reader!)
+      .expect(200);
+    await api()
+      .get(`/api/v1/plugin/pages/${openPageId}/outline`)
+      .set('Cookie', cookies.reader!)
+      .expect(200);
+    const meta = await api()
+      .get(`/api/v1/plugin/pages/${openPageId}/meta`)
+      .set('Cookie', cookies.reader!)
+      .expect(200);
+    expect(meta.body).toMatchObject({ id: openPageId, pondId });
+
+    // …but the denied page reads as nonexistent through the plugin API too.
+    await api()
+      .get(`/api/v1/plugin/pages/${secretPageId}/content`)
+      .set('Cookie', cookies.reader!)
+      .expect(404);
+    await api()
+      .get(`/api/v1/plugin/pages/${secretPageId}/outline`)
+      .set('Cookie', cookies.reader!)
+      .expect(404);
+  });
+
+  it('hides everything from a non-member (404) and rejects anonymous callers (401)', async () => {
+    // An authenticated non-member sees 404 (existence hidden) — the same read
+    // policy the rest of the app enforces, inherited via the shared guards.
+    await api()
+      .get(`/api/v1/plugin/ponds/${pondId}/pages`)
+      .set('Cookie', cookies.foreign!)
+      .expect(404);
+    await api()
+      .get(`/api/v1/plugin/pages/${openPageId}/content`)
+      .set('Cookie', cookies.foreign!)
+      .expect(404);
+    // The plugin API runs with the viewer's session; there is no anonymous
+    // viewer (public read is the separate #56 path), so auth rejects first.
+    await api().get(`/api/v1/plugin/pages/${openPageId}/meta`).expect(401);
+  });
+});

apps/web/src/plugins/PluginFrame.tsx

@@ -3,12 +3,15 @@ import { useTranslation } from 'react-i18next';
 
 import type { HostCapabilityHandlers } from '@dorfteich/plugin-sdk';
 
+import { type PluginHostContext } from './host-capabilities';
 import { createPluginSandbox, type SandboxPluginRef, type SandboxState } from './sandbox-host';
 
 export interface PluginFrameProps {
   plugin: SandboxPluginRef;
   extensionPointId: string;
-  /** Host capability implementations for this surface (grows with #74). */
+  /** The page/pond the surface views + UI actions (#74 read + ui capabilities). */
+  context?: PluginHostContext;
+  /** Surface-specific host capability overrides (e.g. #76 blockData). */
   capabilities?: HostCapabilityHandlers;
   /** Block data for block surfaces (#76). */
   data?: unknown;
@@ -23,6 +26,7 @@ export interface PluginFrameProps {
 export function PluginFrame({
   plugin,
   extensionPointId,
+  context,
   capabilities,
   data,
 }: PluginFrameProps): React.JSX.Element {
@@ -39,14 +43,15 @@ export function PluginFrame({
       extensionPointId,
       locale: i18n.language,
       container,
+      context,
       capabilities,
       data,
       onStateChange: setState,
     });
     return () => sandbox.destroy();
-    // `capabilities`/`data` identity is owned by the parent surface; remounting
-    // on plugin/extension change is what resets the sandbox.
-  }, [plugin.id, plugin.version, extensionPointId, i18n.language, capabilities, data]);
+    // `context`/`capabilities`/`data` identity is owned by the parent surface;
+    // remounting on plugin/extension change is what resets the sandbox.
+  }, [plugin.id, plugin.version, extensionPointId, i18n.language, context, capabilities, data]);
 
   return (
     <div className="plugin-frame-host" data-plugin-id={plugin.id} data-state={state}>

apps/web/src/plugins/host-capabilities.test.ts

@@ -0,0 +1,54 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+import { apiGet } from '../lib/api';
+
+import { buildHostCapabilities } from './host-capabilities';
+
+vi.mock('../lib/api', () => ({ apiGet: vi.fn() }));
+
+const mockedGet = vi.mocked(apiGet);
+
+describe('buildHostCapabilities', () => {
+  beforeEach(() => mockedGet.mockReset());
+
+  it('maps the read capabilities to the viewer-scoped plugin endpoints', async () => {
+    mockedGet.mockResolvedValueOnce([{ id: 'h1', level: 1, text: 'Hi' }]);
+    mockedGet.mockResolvedValueOnce({ markdown: '# Hi' });
+    mockedGet.mockResolvedValueOnce([{ id: 'p2', title: 'Two', slug: 'two' }]);
+
+    const caps = buildHostCapabilities({ pageId: 'p1', pondId: 'pond1' });
+
+    await caps.getOutline!(undefined);
+    expect(mockedGet).toHaveBeenLastCalledWith('/plugin/pages/p1/outline');
+
+    await expect(caps.getContent!(undefined)).resolves.toBe('# Hi');
+    expect(mockedGet).toHaveBeenLastCalledWith('/plugin/pages/p1/content');
+
+    await caps.listPages!(undefined);
+    expect(mockedGet).toHaveBeenLastCalledWith('/plugin/ponds/pond1/pages');
+  });
+
+  it('encodes the page id argument for getPageContent/getPageOutline', async () => {
+    mockedGet.mockResolvedValue([]);
+    const caps = buildHostCapabilities({ pageId: 'p1', pondId: 'pond1' });
+    await caps.getPageOutline!('weird/id');
+    expect(mockedGet).toHaveBeenLastCalledWith('/plugin/pages/weird%2Fid/outline');
+  });
+
+  it('rejects read calls that need context the surface does not have', async () => {
+    const caps = buildHostCapabilities({}); // no page, no pond
+    await expect(caps.getOutline!(undefined)).rejects.toThrow(/current page/);
+    await expect(caps.listPages!(undefined)).rejects.toThrow(/pond/);
+    expect(mockedGet).not.toHaveBeenCalled();
+  });
+
+  it('routes ui.openPage / ui.toast to the host callbacks', () => {
+    const openPage = vi.fn();
+    const toast = vi.fn();
+    const caps = buildHostCapabilities({ pageId: 'p1', openPage, toast });
+    caps.openPage!('target-page');
+    caps.toast!('saved');
+    expect(openPage).toHaveBeenCalledWith('target-page');
+    expect(toast).toHaveBeenCalledWith('saved');
+  });
+});

apps/web/src/plugins/host-capabilities.ts

@@ -0,0 +1,74 @@
+import type { HostCapabilityHandlers } from '@dorfteich/plugin-sdk';
+import type {
+  OutlineEntry,
+  PluginPageContent,
+  PluginPageMeta,
+  PluginPageSummary,
+} from '@dorfteich/shared';
+
+import { apiGet } from '../lib/api';
+
+/**
+ * The surface a plugin runs against (issue #74): which page/pond it is viewing
+ * and how the host performs UI actions on its behalf. The host, not the plugin,
+ * holds the current ids — a plugin can only ask about "the current page" or
+ * pages of "this pond", never arbitrary ones.
+ */
+export interface PluginHostContext {
+  pageId?: string;
+  pondId?: string;
+  /** Navigate to a page (the `ui.openPage` capability). */
+  openPage?: (pageId: string) => void;
+  /** Show a localized toast (the `ui.toast` capability). */
+  toast?: (messageKey: string) => void;
+}
+
+/**
+ * Builds the host implementations of the plugin API methods for one surface.
+ * Every data method calls the viewer-scoped `/plugin/*` endpoints (#74), so
+ * permission enforcement stays server-side. Only methods whose capability the
+ * plugin declared are ever reached — the SDK host bridge gates them.
+ */
+export function buildHostCapabilities(context: PluginHostContext): HostCapabilityHandlers {
+  const requireCurrentPage = (): string => {
+    if (!context.pageId) throw new Error('no current page for this plugin surface');
+    return context.pageId;
+  };
+  const requirePond = (): string => {
+    if (!context.pondId) throw new Error('no pond for this plugin surface');
+    return context.pondId;
+  };
+
+  return {
+    // readCurrentPage — bound to the host-held current page id. Async so a
+    // missing-context error surfaces as a rejection, not a synchronous throw.
+    getOutline: async () => apiGet<OutlineEntry[]>(`/plugin/pages/${requireCurrentPage()}/outline`),
+    getContent: async () =>
+      (await apiGet<PluginPageContent>(`/plugin/pages/${requireCurrentPage()}/content`)).markdown,
+    getMeta: async () => apiGet<PluginPageMeta>(`/plugin/pages/${requireCurrentPage()}/meta`),
+
+    // readPond — scoped to the surface's pond; page ids are validated by the
+    // server's read guard, so an out-of-pond id simply 404s for the viewer.
+    listPages: async () => apiGet<PluginPageSummary[]>(`/plugin/ponds/${requirePond()}/pages`),
+    getPageOutline: async (params) =>
+      apiGet<OutlineEntry[]>(`/plugin/pages/${asPageId(params)}/outline`),
+    getPageContent: async (params) =>
+      (await apiGet<PluginPageContent>(`/plugin/pages/${asPageId(params)}/content`)).markdown,
+
+    // ui — host-side effects; resize is added by the sandbox itself.
+    openPage: (params) => {
+      context.openPage?.(asPageId(params));
+    },
+    toast: (params) => {
+      if (typeof params === 'string') context.toast?.(params);
+    },
+  };
+}
+
+/** A single-string argument arrives as `params` (SDK `toParams`). */
+function asPageId(params: unknown): string {
+  if (typeof params !== 'string' || params.length === 0) {
+    throw new Error('a page id is required');
+  }
+  return encodeURIComponent(params);
+}

apps/web/src/plugins/sandbox-host.ts

@@ -18,6 +18,7 @@ import {
 } from '@dorfteich/plugin-sdk';
 
 import { frameTransport } from './frame-transport';
+import { buildHostCapabilities, type PluginHostContext } from './host-capabilities';
 
 /** Deadline for the frame to load and answer its first `render` call. */
 export const RENDER_TIMEOUT_MS = 5000;
@@ -45,9 +46,13 @@ export interface CreateSandboxOptions {
   locale: string;
   /** Element the iframe is appended to. */
   container: HTMLElement;
-  /** Host implementations of capability methods (grows with #74). The `ui`
-   * method `resize` has a built-in default; pass your own to override. */
+  /** Extra/override host capability handlers. The read capabilities and `ui`
+   * are derived from `context`; anything here is merged on top (e.g. #76's
+   * blockData). The built-in `ui.resize` is always applied. */
   capabilities?: HostCapabilityHandlers;
+  /** The page/pond the surface views + UI actions, backing the read and `ui`
+   * capabilities (#74). */
+  context?: PluginHostContext;
   /** Block data passed to `render`/`edit` (block surfaces, #76). */
   data?: unknown;
   renderTimeoutMs?: number;
@@ -86,6 +91,8 @@ export function createPluginSandbox(options: CreateSandboxOptions): PluginSandbo
   };
 
   const capabilities: HostCapabilityHandlers = {
+    // Viewer-scoped read + ui handlers derived from the surface context (#74).
+    ...(options.context ? buildHostCapabilities(options.context) : {}),
     // Built-in `ui.resize`: plugins size their own frame, clamped so a hostile
     // plugin cannot blow up the layout. Still gated: only manifests declaring
     // the `ui` capability ever reach this handler.
@@ -95,6 +102,7 @@ export function createPluginSandbox(options: CreateSandboxOptions): PluginSandbo
       const clamped = Math.min(MAX_FRAME_HEIGHT_PX, Math.max(MIN_FRAME_HEIGHT_PX, height));
       iframe.style.height = `${clamped}px`;
     },
+    // Surface-specific overrides (e.g. #76 blockData) win over the defaults.
     ...options.capabilities,
   };
 

packages/shared/src/plugins.ts

@@ -83,3 +83,26 @@ export const pondPluginToggleInputSchema = z.object({
   enabled: z.boolean(),
 });
 export type PondPluginToggleInput = z.infer<typeof pondPluginToggleInputSchema>;
+
+/**
+ * Responses of the viewer-scoped plugin API (issue #74, `/api/v1/plugin/…`).
+ * Every call runs with the requesting user's session behind the standard
+ * permission guards, so a plugin never sees more than its viewer could. The
+ * heading outline reuses the editor's `OutlineEntry` (see editor-schema).
+ */
+export interface PluginPageSummary {
+  id: string;
+  title: string;
+  slug: string;
+}
+
+export interface PluginPageMeta {
+  id: string;
+  title: string;
+  pondId: string;
+  slug: string;
+}
+
+export interface PluginPageContent {
+  markdown: string;
+}