feat(content): graphql subgraph with dataloader for textbook/chapter/kp/question

- GraphQLModule: Apollo Federation 2 at /graphql

- Textbook/Chapter/KnowledgePoint/Question @key with @ResolveReference

- RouterAuthGuard: validate Router-Authorization header (ADR-036)

- batchFind methods added to 4 repositories

- Domain modules export repositories for GraphqlModule injection

services/content/package.json

@@ -12,10 +12,14 @@
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
+    "@apollo/subgraph": "^2.2.3",
+    "@edu/shared-ts": "workspace:*",
     "@grpc/grpc-js": "^1.12.0",
     "@grpc/proto-loader": "^0.7.13",
+    "@nestjs/apollo": "^12.2.0",
     "@nestjs/common": "^10.4.0",
     "@nestjs/core": "^10.4.0",
+    "@nestjs/graphql": "^12.2.0",
     "@nestjs/microservices": "^10.4.0",
     "@nestjs/platform-express": "^10.4.0",
     "@opentelemetry/api": "^1.9.0",
@@ -24,7 +28,9 @@
     "@opentelemetry/sdk-node": "^0.55.0",
     "@elastic/elasticsearch": "^8.13.0",
     "@paralleldrive/cuid2": "^2.2.2",
+    "dataloader": "^2.2.2",
     "drizzle-orm": "^0.31.0",
+    "graphql": "^16.9.0",
     "kafkajs": "^2.2.4",
     "mysql2": "^3.11.0",
     "neo4j-driver": "^5.23.0",

services/content/src/app.module.ts

@@ -12,6 +12,8 @@ import { HealthModule } from "./shared/health/health.module.js";
 import { OutboxModule } from "./shared/outbox/outbox.module.js";
 import { PermissionGuard } from "./middleware/permission.guard.js";
 import { LifecycleService } from "./shared/lifecycle/lifecycle.service.js";
+import { GraphqlModule } from "./graphql/graphql.module.js";
+import { RouterAuthGuard } from "./graphql/router-auth.guard.js";
 
 @Module({
   imports: [
@@ -25,9 +27,11 @@ import { LifecycleService } from "./shared/lifecycle/lifecycle.service.js";
     GrpcModule,
     HealthModule,
     OutboxModule,
+    GraphqlModule,
   ],
   providers: [
     { provide: APP_GUARD, useClass: PermissionGuard },
+    { provide: APP_GUARD, useClass: RouterAuthGuard },
     LifecycleService,
   ],
 })

services/content/src/chapters/chapters.module.ts

@@ -1,12 +1,13 @@
 import { Module } from "@nestjs/common";
 import { ChaptersController } from "./chapters.controller.js";
 import { ChaptersService } from "./chapters.service.js";
+import { ChaptersRepository } from "./chapters.repository.js";
 import { OutboxModule } from "../shared/outbox/outbox.module.js";
 
 @Module({
   imports: [OutboxModule],
   controllers: [ChaptersController],
-  providers: [ChaptersService],
+  providers: [ChaptersService, ChaptersRepository],
-  exports: [ChaptersService],
+  exports: [ChaptersService, ChaptersRepository],
 })
 export class ChaptersModule {}

services/content/src/chapters/chapters.repository.ts

@@ -1,4 +1,4 @@
-import { eq } from "drizzle-orm";
+import { eq, inArray } from "drizzle-orm";
 import { getDb } from "../config/database.js";
 import { chapters, type Chapter, type NewChapter } from "./chapters.schema.js";
 
@@ -12,6 +12,14 @@ export class ChaptersRepository {
     return result;
   }
 
+  /**
+   * 批量查询（DataLoader @key 解析器使用，ADR-035）
+   */
+  async batchFind(ids: string[]): Promise<Chapter[]> {
+    if (ids.length === 0) return [];
+    return getDb().select().from(chapters).where(inArray(chapters.id, ids));
+  }
+
   async findByTextbookId(textbookId: string): Promise<Chapter[]> {
     return getDb()
       .select()

services/content/src/graphql/dataloader.service.ts

@@ -0,0 +1,166 @@
+/**
+ * content DataLoader 服务（v2.1 M1 / ADR-035）
+ *
+ * 强制约束：@key Reference Resolver 必须使用 DataLoader 请求合并。
+ *
+ * 每个 GraphQL 请求独立 DataLoader 实例（请求级缓存）。
+ * 通过 REQUEST scope 注入，确保不同请求不共享缓存。
+ */
+import { Injectable, Scope } from "@nestjs/common";
+import DataLoader from "dataloader";
+import { createDataLoader } from "@edu/shared-ts/federation";
+import { TextbooksRepository } from "../textbooks/textbooks.repository.js";
+import { ChaptersRepository } from "../chapters/chapters.repository.js";
+import { KnowledgePointsRepository } from "../knowledge-points/knowledge-points.repository.js";
+import { QuestionsRepository } from "../questions/questions.repository.js";
+
+/**
+ * Textbook Entity（GraphQL 输出类型）
+ * 对应 content_textbooks 表
+ */
+export interface TextbookEntity {
+  id: string;
+  title: string;
+  subjectId: string;
+  gradeId: string;
+  version: string;
+  status: string;
+  tenantId: string | null;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+/**
+ * Chapter Entity（GraphQL 输出类型）
+ * 对应 content_chapters 表
+ */
+export interface ChapterEntity {
+  id: string;
+  textbookId: string;
+  title: string;
+  order: number;
+  parentId: string | null;
+  status: string;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+/**
+ * KnowledgePoint Entity（GraphQL 输出类型）
+ * 对应 content_knowledge_points 表
+ */
+export interface KnowledgePointEntity {
+  id: string;
+  chapterId: string;
+  title: string;
+  description: string | null;
+  difficulty: number;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+/**
+ * Question Entity（GraphQL 输出类型）
+ * 对应 content_questions 表
+ */
+export interface QuestionEntity {
+  id: string;
+  knowledgePointId: string;
+  type: string;
+  content: string;
+  answer: string;
+  explanation: string | null;
+  difficulty: number;
+  status: string;
+  source: string;
+  createdBy: string;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+@Injectable({ scope: Scope.REQUEST })
+export class DataLoaderService {
+  private textbookLoaderInstance: DataLoader<
+    string,
+    TextbookEntity | null
+  > | null = null;
+  private chapterLoaderInstance: DataLoader<
+    string,
+    ChapterEntity | null
+  > | null = null;
+  private knowledgePointLoaderInstance: DataLoader<
+    string,
+    KnowledgePointEntity | null
+  > | null = null;
+  private questionLoaderInstance: DataLoader<
+    string,
+    QuestionEntity | null
+  > | null = null;
+
+  constructor(
+    private readonly textbooksRepository: TextbooksRepository,
+    private readonly chaptersRepository: ChaptersRepository,
+    private readonly knowledgePointsRepository: KnowledgePointsRepository,
+    private readonly questionsRepository: QuestionsRepository,
+  ) {}
+
+  /** Textbook @key 解析器 DataLoader */
+  get textbookLoader(): DataLoader<string, TextbookEntity | null> {
+    if (!this.textbookLoaderInstance) {
+      this.textbookLoaderInstance = createDataLoader<
+        string,
+        TextbookEntity | null
+      >(async (ids) => {
+        const rows = await this.textbooksRepository.batchFind([...ids]);
+        const map = new Map(rows.map((r) => [r.id, r]));
+        return ids.map((id) => map.get(id) ?? null);
+      });
+    }
+    return this.textbookLoaderInstance;
+  }
+
+  /** Chapter @key 解析器 DataLoader */
+  get chapterLoader(): DataLoader<string, ChapterEntity | null> {
+    if (!this.chapterLoaderInstance) {
+      this.chapterLoaderInstance = createDataLoader<
+        string,
+        ChapterEntity | null
+      >(async (ids) => {
+        const rows = await this.chaptersRepository.batchFind([...ids]);
+        const map = new Map(rows.map((r) => [r.id, r]));
+        return ids.map((id) => map.get(id) ?? null);
+      });
+    }
+    return this.chapterLoaderInstance;
+  }
+
+  /** KnowledgePoint @key 解析器 DataLoader */
+  get knowledgePointLoader(): DataLoader<string, KnowledgePointEntity | null> {
+    if (!this.knowledgePointLoaderInstance) {
+      this.knowledgePointLoaderInstance = createDataLoader<
+        string,
+        KnowledgePointEntity | null
+      >(async (ids) => {
+        const rows = await this.knowledgePointsRepository.batchFind([...ids]);
+        const map = new Map(rows.map((r) => [r.id, r]));
+        return ids.map((id) => map.get(id) ?? null);
+      });
+    }
+    return this.knowledgePointLoaderInstance;
+  }
+
+  /** Question @key 解析器 DataLoader */
+  get questionLoader(): DataLoader<string, QuestionEntity | null> {
+    if (!this.questionLoaderInstance) {
+      this.questionLoaderInstance = createDataLoader<
+        string,
+        QuestionEntity | null
+      >(async (ids) => {
+        const rows = await this.questionsRepository.batchFind([...ids]);
+        const map = new Map(rows.map((r) => [r.id, r]));
+        return ids.map((id) => map.get(id) ?? null);
+      });
+    }
+    return this.questionLoaderInstance;
+  }
+}

services/content/src/graphql/generated/schema.graphql

@@ -0,0 +1,414 @@
+# 自动生成的 GraphQL Federation 子图（v2.1 M0）
+# 源文件：content.proto
+# 请勿手动修改；如需调整，改 proto 后重新运行 pnpm run proto:gen-graphql
+
+extend type Query
+
+type Textbook @key(fields: "id") {
+  id: String
+  title: String
+  subject_id: String
+  grade_id: String
+  version: String
+  status: String
+  tenant_id: String
+  metadata: Struct
+  created_at: String
+  updated_at: String
+}
+
+type Chapter @key(fields: "id") {
+  id: String
+  textbook_id: String
+  title: String
+  order: Int
+  parent_id: String
+  status: String
+  created_at: String
+  updated_at: String
+}
+
+type KnowledgePoint @key(fields: "id") {
+  id: String
+  chapter_id: String
+  title: String
+  description: String
+  difficulty: Int
+  metadata: Struct
+  created_at: String
+  updated_at: String
+}
+
+type Question @key(fields: "id") {
+  id: String
+  knowledge_point_id: String
+  type: String
+  content: String
+  options: Struct
+  answer: String
+  explanation: String
+  difficulty: Int
+  status: String
+  source: String
+  created_by: String
+  metadata: Struct
+  created_at: String
+  updated_at: String
+}
+
+type GetTextbookRequest @key(fields: "id") {
+  id: String
+}
+
+type UpdateTextbookRequest @key(fields: "id") {
+  id: String
+  title: String
+  status: String
+  metadata: Struct
+}
+
+type DeleteTextbookRequest @key(fields: "id") {
+  id: String
+}
+
+type GetChapterRequest @key(fields: "id") {
+  id: String
+}
+
+type UpdateChapterRequest @key(fields: "id") {
+  id: String
+  title: String
+  order: Int
+  status: String
+}
+
+type DeleteChapterRequest @key(fields: "id") {
+  id: String
+}
+
+type GetQuestionRequest @key(fields: "id") {
+  id: String
+}
+
+type UpdateQuestionRequest @key(fields: "id") {
+  id: String
+  content: String
+  answer: String
+  status: String
+  options: Struct
+  explanation: String
+  difficulty: Int
+}
+
+type DeleteQuestionRequest @key(fields: "id") {
+  id: String
+}
+
+type PublishQuestionRequest @key(fields: "id") {
+  id: String
+}
+
+type ElectiveCourse @key(fields: "id") {
+  id: String
+  title: String
+  subject_id: String
+  teacher_id: String
+  capacity: Int
+  enrolled_count: Int
+  status: String
+  description: String
+  created_at: String
+  updated_at: String
+}
+
+type ElectiveSelection @key(fields: "id") {
+  id: String
+  student_id: String
+  course_id: String
+  status: String
+  selected_at: String
+  dropped_at: String
+}
+
+type LessonPlan @key(fields: "id") {
+  id: String
+  teacher_id: String
+  class_id: String
+  subject_id: String
+  title: String
+  content: String
+  status: String
+  metadata: Struct
+  created_at: String
+  updated_at: String
+}
+
+type GetLessonPlanRequest @key(fields: "id") {
+  id: String
+}
+
+type CoursePlan @key(fields: "id") {
+  id: String
+  student_id: String
+  class_id: String
+  subject_id: String
+  title: String
+  plan_type: String
+  content: String
+  status: String
+  metadata: Struct
+  created_at: String
+  updated_at: String
+}
+
+type GetCoursePlanRequest @key(fields: "id") {
+  id: String
+}
+
+type Empty {
+}
+
+input CreateTextbookRequestInput {
+  title: String
+  subject_id: String
+  grade_id: String
+  version: String
+  metadata: Struct
+}
+
+input ListTextbooksRequestInput {
+  subject_id: String
+  grade_id: String
+  page_token: String
+  page_size: Int
+}
+
+input ListTextbooksResponseInput {
+  textbooks: Textbook
+  next_page_token: String
+}
+
+input CreateChapterRequestInput {
+  textbook_id: String
+  title: String
+  order: Int
+  parent_id: String
+}
+
+input ListChaptersRequestInput {
+  textbook_id: String
+  parent_id: String
+}
+
+input ListChaptersResponseInput {
+  chapters: Chapter
+}
+
+input GetPrerequisitesRequestInput {
+  knowledge_point_id: String
+  depth: Int
+}
+
+input KnowledgePointsResponseInput {
+  points: KnowledgePoint
+}
+
+input GetLearningPathRequestInput {
+  student_id: String
+  subject_id: String
+}
+
+type LearningPath {
+  points: KnowledgePoint
+  recommended_order: String
+}
+
+input AddPrerequisiteRequestInput {
+  kp_id: String
+  prerequisite_id: String
+}
+
+input RemovePrerequisiteRequestInput {
+  kp_id: String
+  prerequisite_id: String
+}
+
+input CreateQuestionRequestInput {
+  knowledge_point_id: String
+  type: String
+  content: String
+  options: Struct
+  answer: String
+  explanation: String
+  difficulty: Int
+  source: String
+  created_by: String
+  metadata: Struct
+}
+
+input BatchCreateQuestionsRequestInput {
+  questions: CreateQuestionRequest
+}
+
+input BatchCreateQuestionsResponseInput {
+  ids: String
+  failed: BatchCreateFailure
+}
+
+type BatchCreateFailure {
+  index: Int
+  error: String
+}
+
+input ListQuestionsRequestInput {
+  knowledge_point_id: String
+  type: String
+  difficulty: Int
+  status: String
+  page_token: String
+  page_size: Int
+}
+
+input ListQuestionsResponseInput {
+  questions: Question
+  next_page_token: String
+}
+
+input SearchQuestionsRequestInput {
+  q: String
+  type: String
+  difficulty: Int
+  knowledge_point_id: String
+  page_token: String
+  page_size: Int
+}
+
+input SearchQuestionsResponseInput {
+  questions: Question
+  total: Int
+  next_page_token: String
+}
+
+input GetKnowledgePathRequestInput {
+  class_id: String
+  subject_id: String
+}
+
+input ListAvailableElectiveCoursesRequestInput {
+  subject_id: String
+  page_size: Int
+  page_token: String
+}
+
+input ListElectiveCoursesResponseInput {
+  courses: ElectiveCourse
+  next_page_token: String
+}
+
+input ListElectiveSelectionsByStudentRequestInput {
+  student_id: String
+  status: String
+}
+
+input ListElectiveSelectionsResponseInput {
+  selections: ElectiveSelection
+}
+
+input SelectCourseRequestInput {
+  student_id: String
+  course_id: String
+}
+
+input DropCourseRequestInput {
+  student_id: String
+  course_id: String
+}
+
+input ListLessonPlansByTeacherRequestInput {
+  teacher_id: String
+  class_id: String
+  subject_id: String
+}
+
+input ListLessonPlansByStudentRequestInput {
+  student_id: String
+  class_id: String
+}
+
+input ListLessonPlansResponseInput {
+  lesson_plans: LessonPlan
+}
+
+input ListCoursePlansByStudentRequestInput {
+  student_id: String
+  class_id: String
+  plan_type: String
+}
+
+input ListCoursePlansResponseInput {
+  course_plans: CoursePlan
+}
+
+extend type Query {
+  textbook: Textbook
+}
+
+extend type Query {
+  textbooks: [ListTextbooksResponse!]!
+}
+
+extend type Query {
+  chapter: Chapter
+}
+
+extend type Query {
+  chapters: [ListChaptersResponse!]!
+}
+
+extend type Query {
+  prerequisites: KnowledgePointsResponse
+}
+
+extend type Query {
+  learningPath: LearningPath
+}
+
+extend type Query {
+  knowledgePath: LearningPath
+}
+
+extend type Query {
+  question: Question
+}
+
+extend type Query {
+  questions: [ListQuestionsResponse!]!
+}
+
+extend type Query {
+  availableElectiveCourses: [ListElectiveCoursesResponse!]!
+}
+
+extend type Query {
+  electiveSelectionsByStudent: [ListElectiveSelectionsResponse!]!
+}
+
+extend type Query {
+  lessonPlansByTeacher: [ListLessonPlansResponse!]!
+}
+
+extend type Query {
+  lessonPlansByStudent: [ListLessonPlansResponse!]!
+}
+
+extend type Query {
+  lessonPlan: LessonPlan
+}
+
+extend type Query {
+  coursePlansByStudent: [ListCoursePlansResponse!]!
+}
+
+extend type Query {
+  coursePlan: CoursePlan
+}

services/content/src/graphql/graphql.module.ts

@@ -0,0 +1,63 @@
+/**
+ * content GraphQL 子图模块（v2.1 M1）
+ *
+ * Apollo Federation 2 子图，替代原 teacher-bff 的聚合职责。
+ *
+ * 强制约束：
+ * - @key 解析器必须使用 DataLoader（ADR-035）
+ * - RouterAuthGuard 校验 Router-Authorization Header（ADR-036）
+ * - 外部 GraphQL + 内部 gRPC 边界（ADR-037）
+ */
+import { Module } from "@nestjs/common";
+import { GraphQLModule } from "@nestjs/graphql";
+import { ApolloDriver, ApolloDriverConfig } from "@nestjs/apollo";
+import { join } from "node:path";
+import { GraphqlContext } from "@edu/shared-ts/federation";
+import { TextbooksModule } from "../textbooks/textbooks.module.js";
+import { ChaptersModule } from "../chapters/chapters.module.js";
+import { KnowledgePointsModule } from "../knowledge-points/knowledge-points.module.js";
+import { QuestionsModule } from "../questions/questions.module.js";
+import { TextbookResolver } from "./resolvers/textbook.resolver.js";
+import { ChapterResolver } from "./resolvers/chapter.resolver.js";
+import { KnowledgePointResolver } from "./resolvers/knowledge-point.resolver.js";
+import { QuestionResolver } from "./resolvers/question.resolver.js";
+import { DataLoaderService } from "./dataloader.service.js";
+
+@Module({
+  imports: [
+    // 导入领域模块以注入 Repository（@key DataLoader 批量加载）
+    TextbooksModule,
+    ChaptersModule,
+    KnowledgePointsModule,
+    QuestionsModule,
+    GraphQLModule.forRoot<ApolloDriverConfig>({
+      driver: ApolloDriver,
+      // Federation 2 子图
+      autoSchemaFile: {
+        path: join(process.cwd(), "src/graphql/generated/schema.graphql"),
+        federation: 2,
+      },
+      // /graphql 端点（Apollo Router 访问入口）
+      path: "/graphql",
+      // 禁用 playground（生产环境通过 Router 访问）
+      playground: process.env.NODE_ENV === "development",
+      introspection: process.env.NODE_ENV === "development",
+      // Context 从 HTTP headers 构造
+      context: (ctx: {
+        req: { headers: Record<string, string | undefined> };
+      }) => ({
+        req: ctx.req,
+        graphqlContext: GraphqlContext.fromHeaders(ctx.req.headers),
+      }),
+    }),
+  ],
+  providers: [
+    TextbookResolver,
+    ChapterResolver,
+    KnowledgePointResolver,
+    QuestionResolver,
+    DataLoaderService,
+  ],
+  exports: [DataLoaderService],
+})
+export class GraphqlModule {}

services/content/src/graphql/resolvers/chapter.resolver.ts

@@ -0,0 +1,80 @@
+/**
+ * content Chapter Resolver（v2.1 M1）
+ *
+ * Apollo Federation 子图：Chapter Entity
+ * - @key(fields: "id") 支持跨子图引用
+ * - @ResolveReference 使用 DataLoader 批量加载（ADR-035）
+ */
+import {
+  Resolver,
+  Query,
+  Args,
+  ID,
+  ResolveReference,
+  ObjectType,
+  Field,
+  Directive,
+} from "@nestjs/graphql";
+import {
+  DataLoaderService,
+  type ChapterEntity,
+} from "../dataloader.service.js";
+
+/**
+ * Chapter ObjectType（Federation @key）
+ * 对应 content_chapters 表
+ */
+@ObjectType()
+@Directive(`@key(fields: "id")`)
+export class Chapter {
+  @Field(() => ID)
+  id!: string;
+
+  @Field()
+  textbookId!: string;
+
+  @Field()
+  title!: string;
+
+  @Field()
+  order!: number;
+
+  @Field({ nullable: true })
+  parentId: string | null = null;
+
+  @Field()
+  status!: string;
+
+  @Field()
+  createdAt!: Date;
+
+  @Field()
+  updatedAt!: Date;
+}
+
+@Resolver(() => Chapter)
+export class ChapterResolver {
+  constructor(private readonly loader: DataLoaderService) {}
+
+  /**
+   * Federation Reference Resolver
+   *
+   * 当其他子图通过 @key 引用 Chapter 时，Router 调用此方法解析。
+   * 使用 DataLoader 批量加载，消除 N+1 查询（ADR-035）。
+   */
+  @ResolveReference()
+  async resolveReference(ref: { id: string }): Promise<ChapterEntity | null> {
+    return this.loader.chapterLoader.load(ref.id);
+  }
+
+  /**
+   * Query: chapter(id) → Chapter
+   * 通过 Apollo Router 访问，直连被 RouterAuthGuard 拒绝（ADR-036）
+   */
+  @Query(() => Chapter, { nullable: true })
+  async chapter(
+    @Args("id", { type: () => ID }) id: string,
+  ): Promise<ChapterEntity | null> {
+    return this.loader.chapterLoader.load(id);
+  }
+}

services/content/src/graphql/resolvers/knowledge-point.resolver.ts

@@ -0,0 +1,79 @@
+/**
+ * content KnowledgePoint Resolver（v2.1 M1）
+ *
+ * Apollo Federation 子图：KnowledgePoint Entity
+ * - @key(fields: "id") 支持跨子图引用
+ * - @ResolveReference 使用 DataLoader 批量加载（ADR-035）
+ */
+import {
+  Resolver,
+  Query,
+  Args,
+  ID,
+  ResolveReference,
+  ObjectType,
+  Field,
+  Directive,
+} from "@nestjs/graphql";
+import {
+  DataLoaderService,
+  type KnowledgePointEntity,
+} from "../dataloader.service.js";
+
+/**
+ * KnowledgePoint ObjectType（Federation @key）
+ * 对应 content_knowledge_points 表
+ */
+@ObjectType()
+@Directive(`@key(fields: "id")`)
+export class KnowledgePoint {
+  @Field(() => ID)
+  id!: string;
+
+  @Field()
+  chapterId!: string;
+
+  @Field()
+  title!: string;
+
+  @Field({ nullable: true })
+  description: string | null = null;
+
+  @Field()
+  difficulty!: number;
+
+  @Field()
+  createdAt!: Date;
+
+  @Field()
+  updatedAt!: Date;
+}
+
+@Resolver(() => KnowledgePoint)
+export class KnowledgePointResolver {
+  constructor(private readonly loader: DataLoaderService) {}
+
+  /**
+   * Federation Reference Resolver
+   *
+   * 当其他子图通过 @key 引用 KnowledgePoint 时，Router 调用此方法解析。
+   * 使用 DataLoader 批量加载，消除 N+1 查询（ADR-035）。
+   */
+  @ResolveReference()
+  async resolveReference(ref: {
+    id: string;
+  }): Promise<KnowledgePointEntity | null> {
+    return this.loader.knowledgePointLoader.load(ref.id);
+  }
+
+  /**
+   * Query: knowledgePoint(id) → KnowledgePoint
+   * 通过 Apollo Router 访问，直连被 RouterAuthGuard 拒绝（ADR-036）
+   */
+  @Query(() => KnowledgePoint, { nullable: true })
+  async knowledgePoint(
+    @Args("id", { type: () => ID }) id: string,
+  ): Promise<KnowledgePointEntity | null> {
+    return this.loader.knowledgePointLoader.load(id);
+  }
+}

services/content/src/graphql/resolvers/question.resolver.ts

@@ -0,0 +1,92 @@
+/**
+ * content Question Resolver（v2.1 M1）
+ *
+ * Apollo Federation 子图：Question Entity
+ * - @key(fields: "id") 支持跨子图引用
+ * - @ResolveReference 使用 DataLoader 批量加载（ADR-035）
+ */
+import {
+  Resolver,
+  Query,
+  Args,
+  ID,
+  ResolveReference,
+  ObjectType,
+  Field,
+  Directive,
+} from "@nestjs/graphql";
+import {
+  DataLoaderService,
+  type QuestionEntity,
+} from "../dataloader.service.js";
+
+/**
+ * Question ObjectType（Federation @key）
+ * 对应 content_questions 表
+ */
+@ObjectType()
+@Directive(`@key(fields: "id")`)
+export class Question {
+  @Field(() => ID)
+  id!: string;
+
+  @Field()
+  knowledgePointId!: string;
+
+  @Field()
+  type!: string;
+
+  @Field()
+  content!: string;
+
+  @Field()
+  answer!: string;
+
+  @Field({ nullable: true })
+  explanation: string | null = null;
+
+  @Field()
+  difficulty!: number;
+
+  @Field()
+  status!: string;
+
+  @Field()
+  source!: string;
+
+  @Field()
+  createdBy!: string;
+
+  @Field()
+  createdAt!: Date;
+
+  @Field()
+  updatedAt!: Date;
+}
+
+@Resolver(() => Question)
+export class QuestionResolver {
+  constructor(private readonly loader: DataLoaderService) {}
+
+  /**
+   * Federation Reference Resolver
+   *
+   * 当其他子图通过 @key 引用 Question 时，Router 调用此方法解析。
+   * 使用 DataLoader 批量加载，消除 N+1 查询（ADR-035）。
+   */
+  @ResolveReference()
+  async resolveReference(ref: { id: string }): Promise<QuestionEntity | null> {
+    return this.loader.questionLoader.load(ref.id);
+  }
+
+  /**
+   * Query: question(id) → Question
+   * 通过 Apollo Router 访问，直连被 RouterAuthGuard 拒绝（ADR-036）
+   */
+  @Query(() => Question, { nullable: true })
+  async question(
+    @Args("id", { type: () => ID }) id: string,
+  ): Promise<QuestionEntity | null> {
+    return this.loader.questionLoader.load(id);
+  }
+}

services/content/src/graphql/resolvers/textbook.resolver.ts

@@ -0,0 +1,84 @@
+/**
+ * content Textbook Resolver（v2.1 M1）
+ *
+ * Apollo Federation 子图：Textbook Entity
+ * - @key(fields: "id") 支持跨子图引用
+ * - @ResolveReference 使用 DataLoader 批量加载（ADR-035）
+ * - Query 入口供 Apollo Router 直接查询
+ */
+import {
+  Resolver,
+  Query,
+  Args,
+  ID,
+  ResolveReference,
+  ObjectType,
+  Field,
+  Directive,
+} from "@nestjs/graphql";
+import {
+  DataLoaderService,
+  type TextbookEntity,
+} from "../dataloader.service.js";
+
+/**
+ * Textbook ObjectType（Federation @key）
+ * 对应 content_textbooks 表
+ */
+@ObjectType()
+@Directive(`@key(fields: "id")`)
+export class Textbook {
+  @Field(() => ID)
+  id!: string;
+
+  @Field()
+  title!: string;
+
+  @Field()
+  subjectId!: string;
+
+  @Field()
+  gradeId!: string;
+
+  @Field()
+  version!: string;
+
+  @Field()
+  status!: string;
+
+  @Field({ nullable: true })
+  tenantId: string | null = null;
+
+  @Field()
+  createdAt!: Date;
+
+  @Field()
+  updatedAt!: Date;
+}
+
+@Resolver(() => Textbook)
+export class TextbookResolver {
+  constructor(private readonly loader: DataLoaderService) {}
+
+  /**
+   * Federation Reference Resolver
+   *
+   * 当其他子图通过 @key 引用 Textbook 时，Router 调用此方法解析。
+   * 使用 DataLoader 批量加载，消除 N+1 查询（ADR-035）。
+   */
+  @ResolveReference()
+  async resolveReference(ref: { id: string }): Promise<TextbookEntity | null> {
+    return this.loader.textbookLoader.load(ref.id);
+  }
+
+  /**
+   * Query: textbook(id) → Textbook
+   * 通过 Apollo Router 访问，直连被 RouterAuthGuard 拒绝（ADR-036）
+   */
+  @Query(() => Textbook, { nullable: true })
+  async textbook(
+    @Args("id", { type: () => ID }) id: string,
+  ): Promise<TextbookEntity | null> {
+    return this.loader.textbookLoader.load(id);
+  }
+}

services/content/src/graphql/router-auth.guard.ts

@@ -0,0 +1,34 @@
+/**
+ * content RouterAuthGuard 包装（v2.1 ADR-036）
+ *
+ * 仅作用于 /graphql 端点，REST 路由放行（已有 PermissionGuard）。
+ */
+import { Injectable, ExecutionContext } from "@nestjs/common";
+import {
+  RouterAuthGuard as BaseRouterAuthGuard,
+  type RouterAuthConfig,
+} from "@edu/shared-ts/federation";
+
+@Injectable()
+export class RouterAuthGuard extends BaseRouterAuthGuard {
+  constructor() {
+    const config: RouterAuthConfig = {
+      secret: process.env.ROUTER_AUTH_SECRET ?? "",
+      devMode: process.env.DEV_MODE === "true",
+    };
+    super(config);
+  }
+
+  override canActivate(ctx: ExecutionContext): boolean {
+    const req = ctx.switchToHttp().getRequest<{
+      url: string;
+    }>();
+
+    // 仅 GraphQL 端点需要校验，REST 路由放行
+    if (!req.url?.startsWith("/graphql")) {
+      return true;
+    }
+
+    return super.canActivate(ctx);
+  }
+}

services/content/src/knowledge-points/knowledge-points.module.ts

@@ -4,12 +4,13 @@ import {
   KnowledgeGraphController,
 } from "./knowledge-points.controller.js";
 import { KnowledgePointsService } from "./knowledge-points.service.js";
+import { KnowledgePointsRepository } from "./knowledge-points.repository.js";
 import { OutboxModule } from "../shared/outbox/outbox.module.js";
 
 @Module({
   imports: [OutboxModule],
   controllers: [KnowledgePointsController, KnowledgeGraphController],
-  providers: [KnowledgePointsService],
+  providers: [KnowledgePointsService, KnowledgePointsRepository],
-  exports: [KnowledgePointsService],
+  exports: [KnowledgePointsService, KnowledgePointsRepository],
 })
 export class KnowledgePointsModule {}

services/content/src/knowledge-points/knowledge-points.repository.ts

@@ -1,4 +1,4 @@
-import { eq } from "drizzle-orm";
+import { eq, inArray } from "drizzle-orm";
 import { getDb } from "../config/database.js";
 import {
   knowledgePoints,
@@ -16,6 +16,17 @@ export class KnowledgePointsRepository {
     return result;
   }
 
+  /**
+   * 批量查询（DataLoader @key 解析器使用，ADR-035）
+   */
+  async batchFind(ids: string[]): Promise<KnowledgePoint[]> {
+    if (ids.length === 0) return [];
+    return getDb()
+      .select()
+      .from(knowledgePoints)
+      .where(inArray(knowledgePoints.id, ids));
+  }
+
   async findByChapterId(chapterId: string): Promise<KnowledgePoint[]> {
     return getDb()
       .select()

services/content/src/questions/questions.module.ts

@@ -1,12 +1,13 @@
 import { Module } from "@nestjs/common";
 import { QuestionsController } from "./questions.controller.js";
 import { QuestionsService } from "./questions.service.js";
+import { QuestionsRepository } from "./questions.repository.js";
 import { OutboxModule } from "../shared/outbox/outbox.module.js";
 
 @Module({
   imports: [OutboxModule],
   controllers: [QuestionsController],
-  providers: [QuestionsService],
+  providers: [QuestionsService, QuestionsRepository],
-  exports: [QuestionsService],
+  exports: [QuestionsService, QuestionsRepository],
 })
 export class QuestionsModule {}

services/content/src/questions/questions.repository.ts

@@ -1,4 +1,4 @@
-import { eq, like, or, and, count } from "drizzle-orm";
+import { eq, like, or, and, count, inArray } from "drizzle-orm";
 import { getDb } from "../config/database.js";
 import {
   questions,
@@ -16,6 +16,14 @@ export class QuestionsRepository {
     return result;
   }
 
+  /**
+   * 批量查询（DataLoader @key 解析器使用，ADR-035）
+   */
+  async batchFind(ids: string[]): Promise<Question[]> {
+    if (ids.length === 0) return [];
+    return getDb().select().from(questions).where(inArray(questions.id, ids));
+  }
+
   async findByKnowledgePointId(knowledgePointId: string): Promise<Question[]> {
     return getDb()
       .select()

services/content/src/textbooks/textbooks.module.ts

@@ -1,12 +1,13 @@
 import { Module } from "@nestjs/common";
 import { TextbooksController } from "./textbooks.controller.js";
 import { TextbooksService } from "./textbooks.service.js";
+import { TextbooksRepository } from "./textbooks.repository.js";
 import { OutboxModule } from "../shared/outbox/outbox.module.js";
 
 @Module({
   imports: [OutboxModule],
   controllers: [TextbooksController],
-  providers: [TextbooksService],
+  providers: [TextbooksService, TextbooksRepository],
-  exports: [TextbooksService],
+  exports: [TextbooksService, TextbooksRepository],
 })
 export class TextbooksModule {}

services/content/src/textbooks/textbooks.repository.ts

@@ -1,4 +1,4 @@
-import { eq, and } from "drizzle-orm";
+import { eq, and, inArray } from "drizzle-orm";
 import { getDb } from "../config/database.js";
 import {
   textbooks,
@@ -16,6 +16,14 @@ export class TextbooksRepository {
     return result;
   }
 
+  /**
+   * 批量查询（DataLoader @key 解析器使用，ADR-035）
+   */
+  async batchFind(ids: string[]): Promise<Textbook[]> {
+    if (ids.length === 0) return [];
+    return getDb().select().from(textbooks).where(inArray(textbooks.id, ids));
+  }
+
   async find(query?: {
     subjectId?: string;
     gradeId?: string;