Added query for fetching repost count (#305)

Ref https://linear.app/ghost/issue/AP-706

- This adds a repost count so that the UI can display the count along with the repost icon

features/repost-activity.feature

@@ -16,6 +16,7 @@ Feature: Reposting a post/note
     When we repost the object "Note"
     Then the request is accepted
     And the object "Note" should be reposted
+    And the object "Note" should have a repost count of 1
     And a "Announce(Note)" activity is sent to "Alice"
 
   Scenario: Trying to repost a post/note that has already been reposted

features/step_definitions/stepdefs.js

@@ -800,6 +800,26 @@ Then('the object {string} should be reposted', async function (name) {
     assert(found.object.reposted === true);
 });
 
+Then(
+    'the object {string} should have a repost count of {int}',
+    async function (name, repostCount) {
+        const response = await fetchActivityPub(
+            'http://fake-ghost-activitypub/.ghost/activitypub/inbox/index',
+            {
+                headers: {
+                    Accept: 'application/ld+json',
+                },
+            },
+        );
+        const inbox = await response.json();
+        const object = this.objects[name];
+
+        const found = inbox.items.find((item) => item.object.id === object.id);
+
+        assert(found.object.repostCount === repostCount);
+    },
+);
+
 When('we undo the repost of the object {string}', async function (name) {
     const id = this.objects[name].id;
     this.response = await fetchActivityPub(

src/db.ts

@@ -148,6 +148,24 @@ export async function getActivityChildrenCount(activity: ActivityJsonLd) {
     return result[0].count;
 }
 
+export async function getRepostCount(activity: ActivityJsonLd) {
+    const objectId = activity.object.id;
+
+    const result = await client
+        .count('* as count')
+        .from('key_value')
+        .where(function () {
+            this.where(
+                client.raw(
+                    `JSON_EXTRACT(value, "$.object.id") = "${objectId}"`,
+                ),
+            );
+        })
+        .andWhere(client.raw(`JSON_EXTRACT(value, "$.type") = "Announce"`));
+
+    return result[0].count;
+}
+
 export async function getActivityParents(activity: ActivityJsonLd) {
     const parents: ActivityJsonLd[] = [];
 

src/helpers/activitypub/activity.ts

@@ -2,7 +2,7 @@ import { createHash } from 'node:crypto';
 import { Announce, type Context, type KvStore, Like } from '@fedify/fedify';
 
 import type { ContextData } from '../../app';
-import { getActivityChildrenCount } from '../../db';
+import { getActivityChildrenCount, getRepostCount } from '../../db';
 import { lookupActor } from '../../lookup-helpers';
 import { sanitizeHtml } from '../html';
 
@@ -132,9 +132,10 @@ export async function buildActivity(
         }
     }
 
-    // Add the reply count to the object, if it is an object
+    // Add reply count and repost count to the object, if it is an object
     if (typeof item.object !== 'string') {
         item.object.replyCount = await getActivityChildrenCount(item);
+        item.object.repostCount = await getRepostCount(item);
     }
 
     // Return the built item