Updated thread implementation to work with posts instead of activities

refs [AP-721](https://linear.app/ghost/issue/AP-721/update-getactivitythread-to-work-with-posts-instead-of-activities)

Updated thread implementation to work with posts instead of activities as part
of the posts migration

src/app.ts

@@ -99,11 +99,11 @@ import {
     createGetProfileFollowersHandler,
     createGetProfileFollowingHandler,
     createGetProfileHandler,
+    createGetThreadHandler,
     createPostPublishedWebhookHandler,
     createSearchHandler,
     handleCreateNote,
     handleGetActivities,
-    handleGetActivityThread,
     handleGetProfilePosts,
     handleWebhookSiteChanged,
 } from './http/api';
@@ -916,8 +916,8 @@ app.get(
     spanWrapper(handleGetProfilePosts),
 );
 app.get(
-    '/.ghost/activitypub/thread/:object_id',
-    spanWrapper(handleGetActivityThread),
+    '/.ghost/activitypub/thread/:post_ap_id',
+    spanWrapper(createGetThreadHandler(postRepository, accountService)),
 );
 app.get(
     '/.ghost/activitypub/account/:handle',

src/db.ts

@@ -141,32 +141,6 @@ export async function getActivityMetaWithoutJoin(
     return map;
 }
 
-export async function getActivityChildren(activity: ActivityJsonLd) {
-    const objectId = activity.object.id;
-
-    const results = await client
-        .select('value')
-        .from('key_value')
-        .where(function () {
-            // If inReplyTo is a string
-            this.where(
-                client.raw(
-                    `JSON_EXTRACT(value, "$.object.inReplyTo") = "${objectId}"`,
-                ),
-            );
-
-            // If inReplyTo is an object
-            this.orWhere(
-                client.raw(
-                    `JSON_EXTRACT(value, "$.object.inReplyTo.id") = "${objectId}"`,
-                ),
-            );
-        })
-        .andWhere(client.raw(`JSON_EXTRACT(value, "$.type") = "Create"`));
-
-    return results.map((result) => result.value);
-}
-
 export async function getActivityChildrenCount(activity: ActivityJsonLd) {
     const objectId = activity.object.id;
 
@@ -210,51 +184,3 @@ export async function getRepostCount(activity: ActivityJsonLd) {
 
     return result[0].count;
 }
-
-export async function getActivityParents(activity: ActivityJsonLd) {
-    const parents: ActivityJsonLd[] = [];
-
-    const getParent = async (objectId: string) => {
-        const result = await client
-            .select('value')
-            .from('key_value')
-            .where(
-                client.raw(
-                    `JSON_EXTRACT(value, "$.object.id") = "${objectId}"`,
-                ),
-            )
-            .andWhere(client.raw(`JSON_EXTRACT(value, "$.type") = "Create"`));
-
-        if (result.length === 1) {
-            const parent = result[0];
-
-            parents.unshift(parent.value);
-
-            // inReplyTo can be a string or an object
-            const inReplyToId =
-                parent.value.object.inReplyTo?.id ??
-                parent.value.object.inReplyTo;
-
-            if (inReplyToId) {
-                await getParent(inReplyToId);
-            }
-        }
-    };
-
-    await getParent(
-        // inReplyTo can be a string or an object
-        activity.object.inReplyTo?.id ?? activity.object.inReplyTo,
-    );
-
-    return parents;
-}
-
-export async function getActivityForObject(objectId: string) {
-    const result = await client
-        .select('value')
-        .from('key_value')
-        .where(client.raw(`JSON_EXTRACT(value, "$.object.id") = "${objectId}"`))
-        .andWhere(client.raw(`JSON_EXTRACT(value, "$.type") = "Create"`));
-
-    return result[0].value;
-}

src/http/api/activities.ts

@@ -1,12 +1,6 @@
 import { type AppContext, fedify } from '../../app';
-import {
-    getActivityChildren,
-    getActivityForObject,
-    getActivityMeta,
-    getActivityParents,
-} from '../../db';
+import { getActivityMeta } from '../../db';
 import { buildActivity } from '../../helpers/activitypub/activity';
-import { isUri } from '../../helpers/uri';
 import { spanWrapper } from '../../instrumentation';
 
 const GET_ACTIVITIES_DEFAULT_LIMIT = 10;
@@ -259,93 +253,3 @@ export async function handleGetActivities(ctx: AppContext) {
         },
     );
 }
-
-interface ActivityJsonLd {
-    [key: string]: any;
-}
-
-/**
- * Handle a request for an activity thread
- *
- * @param ctx App context instance
- */
-export async function handleGetActivityThread(ctx: AppContext) {
-    const db = ctx.get('db');
-    const globaldb = ctx.get('globaldb');
-    const logger = ctx.get('logger');
-    const apCtx = fedify.createContext(ctx.req.raw as Request, {
-        db,
-        globaldb,
-        logger,
-    });
-
-    // Parse "object_id" from request parameters
-    // /thread/:object_id
-    const paramObjectId = ctx.req.param('object_id');
-    const objectId = paramObjectId ? decodeURIComponent(paramObjectId) : '';
-
-    // If the provided objectId is invalid, return early
-    if (isUri(objectId) === false) {
-        return new Response(null, { status: 400 });
-    }
-
-    const activityJsonLd = await getActivityForObject(objectId);
-
-    // If the activity can not be found, return early
-    if (activityJsonLd === undefined) {
-        return new Response(null, { status: 404 });
-    }
-
-    const items: ActivityJsonLd[] = [activityJsonLd];
-
-    // If the object is a string, fetch the object from the database. We need to
-    // do this because we need the inReplyTo property of the object to find the
-    // parent(s) and children of the activity
-    if (typeof activityJsonLd.object === 'string') {
-        const object = await globaldb.get<ActivityJsonLd>([
-            activityJsonLd.object,
-        ]);
-
-        if (object) {
-            activityJsonLd.object = object;
-        }
-    }
-
-    // Find children (replies) and append to the thread
-    const children = await getActivityChildren(activityJsonLd);
-    items.push(...children);
-
-    // Find parent(s) and prepend to the thread
-    const parents = await getActivityParents(activityJsonLd);
-    items.unshift(...parents);
-
-    // Build the activities so that they have all the data expected by the client
-    const likedRefs = (await db.get<string[]>(['liked'])) || [];
-    const repostedRefs = (await db.get<string[]>(['reposted'])) || [];
-
-    const builtActivities = await Promise.all(
-        items.map((item) =>
-            buildActivity(
-                item.id,
-                globaldb,
-                apCtx,
-                likedRefs,
-                repostedRefs,
-                true,
-            ),
-        ),
-    );
-
-    // Return the response
-    return new Response(
-        JSON.stringify({
-            items: builtActivities,
-        }),
-        {
-            headers: {
-                'Content-Type': 'application/json',
-            },
-            status: 200,
-        },
-    );
-}

src/http/api/index.ts

@@ -4,4 +4,5 @@ export * from './feed';
 export * from './note';
 export * from './profile';
 export * from './search';
+export * from './thread';
 export * from './webhook';

src/http/api/thread.ts

@@ -0,0 +1,51 @@
+import type { AccountService } from 'account/account.service';
+import type { AppContext } from '../../app';
+import type { KnexPostRepository } from '../../post/post.repository.knex';
+import { postToDTO } from './helpers/post';
+
+/**
+ * Create a handler for a request for a thread
+ *
+ * @param postRepository Post repository instance
+ */
+export function createGetThreadHandler(
+    postRepository: KnexPostRepository,
+    accountService: AccountService,
+) {
+    /**
+     * Handle a request for a thread
+     *
+     * @param ctx App context instance
+     */
+    return async function handleGetThread(ctx: AppContext) {
+        const paramPostApId = ctx.req.param('post_ap_id');
+        const postApId = paramPostApId ? decodeURIComponent(paramPostApId) : '';
+
+        if (!postApId) {
+            return new Response(null, { status: 400 });
+        }
+
+        const account = await accountService.getDefaultAccountForSite(
+            ctx.get('site'),
+        );
+
+        const posts = (
+            await postRepository.getThreadByApId(postApId, account.id)
+        ).map(({ post, likedByAccount, repostedByAccount }) => {
+            return postToDTO(post, {
+                likedByMe: likedByAccount,
+                repostedByMe: repostedByAccount,
+                repostedBy: null,
+            });
+        });
+
+        return new Response(
+            JSON.stringify({
+                posts,
+            }),
+            {
+                status: 200,
+            },
+        );
+    };
+}