Refactored PostUpdatedEvent to implement SerializableEvent to comply with ADR-0011

ref https://linear.app/ghost/issue/BER-3164/refactor-postupdatedevent-to-implement-serializableevent-adr-0011

Refactored `PostUpdatedEvent` to implement `SerializableEvent` to comply with ADR-0011

Co-authored-by: Cursor Agent <cursoragent@cursor.com>

Author: mike182uk

src/activitypub/fediverse-bridge.ts

@@ -19,6 +19,7 @@ import {
     buildUpdateActivityAndObjectFromPost,
 } from '@/helpers/activitypub/activity';
 import { PostType } from '@/post/post.entity';
+import type { KnexPostRepository } from '@/post/post.repository.knex';
 import { PostCreatedEvent } from '@/post/post-created.event';
 import { PostDeletedEvent } from '@/post/post-deleted.event';
 import { PostUpdatedEvent } from '@/post/post-updated.event';
@@ -28,6 +29,7 @@ export class FediverseBridge {
         private readonly events: EventEmitter,
         private readonly fedifyContextFactory: FedifyContextFactory,
         private readonly accountService: AccountService,
+        private readonly postRepository: KnexPostRepository,
     ) {}
 
     async init() {
@@ -138,8 +140,8 @@ export class FediverseBridge {
     }
 
     private async handlePostUpdated(event: PostUpdatedEvent) {
-        const post = event.getPost();
-        if (!post.author.isInternal) {
+        const post = await this.postRepository.getById(event.getPostId());
+        if (!post || !post.author.isInternal) {
             return;
         }
 

src/activitypub/fediverse-bridge.unit.test.ts

@@ -12,6 +12,7 @@ import { FediverseBridge } from '@/activitypub/fediverse-bridge';
 import type { UriBuilder } from '@/activitypub/uri';
 import type { FedifyContext } from '@/app';
 import { Post, PostType } from '@/post/post.entity';
+import type { KnexPostRepository } from '@/post/post.repository.knex';
 import { PostCreatedEvent } from '@/post/post-created.event';
 import { PostDeletedEvent } from '@/post/post-deleted.event';
 import { PostUpdatedEvent } from '@/post/post-updated.event';
@@ -29,6 +30,7 @@ vi.mock('node:crypto', async (importOriginal) => {
 describe('FediverseBridge', () => {
     let events: EventEmitter;
     let accountService: AccountService;
+    let postRepository: KnexPostRepository;
     let context: FedifyContext;
     let fedifyContextFactory: FedifyContextFactory;
     let mockUriBuilder: UriBuilder<FedifyObject>;
@@ -39,6 +41,9 @@ describe('FediverseBridge', () => {
         accountService = {
             getAccountById: vi.fn(),
         } as unknown as AccountService;
+        postRepository = {
+            getById: vi.fn(),
+        } as unknown as KnexPostRepository;
         mockUriBuilder = {
             buildObjectUri: vi.fn().mockImplementation((object, { id }) => {
                 return new URL(
@@ -75,6 +80,7 @@ describe('FediverseBridge', () => {
             events,
             fedifyContextFactory,
             accountService,
+            postRepository,
         );
     });
 
@@ -163,6 +169,7 @@ describe('FediverseBridge', () => {
             events,
             fedifyContextFactory,
             accountService,
+            postRepository,
         );
         await bridge.init();
 
@@ -246,6 +253,7 @@ describe('FediverseBridge', () => {
             events,
             fedifyContextFactory,
             accountService,
+            postRepository,
         );
         await bridge.init();
 
@@ -291,6 +299,7 @@ describe('FediverseBridge', () => {
             events,
             fedifyContextFactory,
             accountService,
+            postRepository,
         );
         await bridge.init();
 
@@ -333,6 +342,7 @@ describe('FediverseBridge', () => {
             events,
             fedifyContextFactory,
             accountService,
+            postRepository,
         );
         await bridge.init();
 
@@ -515,10 +525,13 @@ describe('FediverseBridge', () => {
         post.apId = new URL('https://example.com/article/post-456');
         post.publishedAt = new Date('2025-01-01T00:00:00Z');
 
-        const event = new PostUpdatedEvent(post);
+        vi.mocked(postRepository.getById).mockResolvedValue(post);
+
+        const event = new PostUpdatedEvent(456);
         events.emit(PostUpdatedEvent.getName(), event);
 
         await nextTick();
+        expect(postRepository.getById).toHaveBeenCalledWith(456);
         expect(sendActivity).toHaveBeenCalledOnce();
         expect(context.data.globaldb.set).toHaveBeenCalledTimes(2);
 
@@ -547,10 +560,29 @@ describe('FediverseBridge', () => {
         post.content = 'Updated post content';
         post.apId = new URL('https://external.com/article/post-456');
 
-        const event = new PostUpdatedEvent(post);
+        vi.mocked(postRepository.getById).mockResolvedValue(post);
+
+        const event = new PostUpdatedEvent(456);
+        events.emit(PostUpdatedEvent.getName(), event);
+
+        await nextTick();
+        expect(postRepository.getById).toHaveBeenCalledWith(456);
+        expect(sendActivity).not.toHaveBeenCalled();
+        expect(context.data.globaldb.set).not.toHaveBeenCalled();
+    });
+
+    it('should not send update activities on the PostUpdatedEvent if post is not found', async () => {
+        await bridge.init();
+
+        const sendActivity = vi.spyOn(context, 'sendActivity');
+
+        vi.mocked(postRepository.getById).mockResolvedValue(null);
+
+        const event = new PostUpdatedEvent(999);
         events.emit(PostUpdatedEvent.getName(), event);
 
         await nextTick();
+        expect(postRepository.getById).toHaveBeenCalledWith(999);
         expect(sendActivity).not.toHaveBeenCalled();
         expect(context.data.globaldb.set).not.toHaveBeenCalled();
     });

src/app.ts

@@ -122,6 +122,7 @@ import type { PostInteractionCountsService } from '@/post/post-interaction-count
 import { PostInteractionCountsUpdateRequestedEvent } from '@/post/post-interaction-counts-update-requested.event';
 import { PostLikedEvent } from '@/post/post-liked.event';
 import { PostRepostedEvent } from '@/post/post-reposted.event';
+import { PostUpdatedEvent } from '@/post/post-updated.event';
 import type { Site } from '@/site/site.service';
 
 function toLogLevel(level: unknown): LogLevel | null {
@@ -279,6 +280,9 @@ container
 container
     .resolve<EventSerializer>('eventSerializer')
     .register(PostRepostedEvent.getName(), PostRepostedEvent);
+container
+    .resolve<EventSerializer>('eventSerializer')
+    .register(PostUpdatedEvent.getName(), PostUpdatedEvent);
 
 /** Fedify */
 

src/post/post-updated.event.ts

@@ -1,13 +1,30 @@
-import type { Post } from '@/post/post.entity';
+import type { SerializableEvent } from '@/events/event';
 
-export class PostUpdatedEvent {
-    constructor(private readonly post: Post) {}
+export class PostUpdatedEvent implements SerializableEvent {
+    constructor(private readonly postId: number) {}
 
-    getPost(): Post {
-        return this.post;
+    getPostId(): number {
+        return this.postId;
+    }
+
+    getName(): string {
+        return PostUpdatedEvent.getName();
     }
 
     static getName(): string {
         return 'post.updated';
     }
+
+    toJSON(): Record<string, unknown> {
+        return {
+            postId: this.postId,
+        };
+    }
+
+    static fromJSON(data: Record<string, unknown>): PostUpdatedEvent {
+        if (typeof data.postId !== 'number') {
+            throw new Error('postId must be a number');
+        }
+        return new PostUpdatedEvent(data.postId);
+    }
 }

src/post/post-updated.event.unit.test.ts

@@ -0,0 +1,77 @@
+import { describe, expect, it } from 'vitest';
+
+import { PostUpdatedEvent } from '@/post/post-updated.event';
+
+describe('PostUpdatedEvent', () => {
+    describe('getName', () => {
+        it('should return the event name from static method', () => {
+            expect(PostUpdatedEvent.getName()).toBe('post.updated');
+        });
+
+        it('should return the event name from instance method', () => {
+            const event = new PostUpdatedEvent(123);
+
+            expect(event.getName()).toBe('post.updated');
+        });
+    });
+
+    describe('getPostId', () => {
+        it('should return the post id', () => {
+            const event = new PostUpdatedEvent(123);
+
+            expect(event.getPostId()).toBe(123);
+        });
+    });
+
+    describe('toJSON', () => {
+        it('should serialize the event to JSON', () => {
+            const event = new PostUpdatedEvent(123);
+
+            expect(event.toJSON()).toEqual({
+                postId: 123,
+            });
+        });
+    });
+
+    describe('fromJSON', () => {
+        it('should deserialize the event from JSON', () => {
+            const event = PostUpdatedEvent.fromJSON({
+                postId: 123,
+            });
+
+            expect(event.getPostId()).toBe(123);
+        });
+
+        it('should throw an error if postId is missing', () => {
+            expect(() => PostUpdatedEvent.fromJSON({})).toThrow(
+                'postId must be a number',
+            );
+        });
+
+        it('should throw an error if postId is not a number', () => {
+            expect(() =>
+                PostUpdatedEvent.fromJSON({
+                    postId: 'not a number',
+                }),
+            ).toThrow('postId must be a number');
+        });
+
+        it('should throw an error if postId is null', () => {
+            expect(() =>
+                PostUpdatedEvent.fromJSON({
+                    postId: null,
+                }),
+            ).toThrow('postId must be a number');
+        });
+    });
+
+    describe('round-trip serialization', () => {
+        it('should correctly serialize and deserialize', () => {
+            const original = new PostUpdatedEvent(999);
+            const json = original.toJSON();
+            const restored = PostUpdatedEvent.fromJSON(json);
+
+            expect(restored.getPostId()).toBe(original.getPostId());
+        });
+    });
+});

src/post/post.repository.knex.integration.test.ts

@@ -2094,14 +2094,14 @@ describe('KnexPostRepository', () => {
             expect(eventsEmitSpy).toHaveBeenCalledWith(
                 PostUpdatedEvent.getName(),
                 expect.objectContaining({
-                    getPost: expect.any(Function),
+                    getPostId: expect.any(Function),
                 }),
             );
 
             const emittedEvent = eventsEmitSpy.mock.calls.find(
                 (call) => call[0] === PostUpdatedEvent.getName(),
-            )?.[1];
-            expect(emittedEvent?.getPost()).toEqual(post);
+            )?.[1] as PostUpdatedEvent | undefined;
+            expect(emittedEvent?.getPostId()).toEqual(post.id);
 
             const updatedRowInDb = await client('posts')
                 .where({ uuid: post.uuid })

src/post/post.repository.knex.ts

@@ -516,7 +516,7 @@ export class KnexPostRepository {
             if (wasUpdated) {
                 await this.events.emitAsync(
                     PostUpdatedEvent.getName(),
-                    new PostUpdatedEvent(post),
+                    new PostUpdatedEvent(post.id as number),
                 );
             }