From b317cdd365f267437310d9cbfc2bc8ce6fe24021 Mon Sep 17 00:00:00 2001
From: Julian Lam <julian@nodebb.org>
Date: Wed, 11 Mar 2026 14:53:06 -0400
Subject: [PATCH] feat: category group actor outbox, #14083

---
 src/controllers/activitypub/index.js | 35 ++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/controllers/activitypub/index.js b/src/controllers/activitypub/index.js
index 1a55109903..db1441aa1b 100644
--- a/src/controllers/activitypub/index.js
+++ b/src/controllers/activitypub/index.js
@@ -215,12 +215,39 @@ Controller.getOutbox = async (req, res) => {
 };
 
 Controller.getCategoryOutbox = async (req, res) => {
-	// stub
+	const { cid } = req.params;
+	const { page } = req.query;
+	const set = `cid:${cid}:pids`;
+	const count = await db.sortedSetCard(set);
+	const collection = await activitypub.helpers.generateCollection({
+		set,
+		count,
+		page,
+		perPage: 20,
+		url: `${nconf.get('url')}/category/1/outbox`,
+	});
+	collection.orderedItems = await Promise.all(collection.orderedItems.map(async (pid) => {
+		let object;
+		if (utils.isNumber(pid)) {
+			const { activity } = await activitypub.mocks.activities.create(pid, 0);
+			object = activity;
+		} else {
+			object = pid;
+		}
+
+		return {
+			id: `${nconf.get('url')}/post/${encodeURIComponent(pid)}#activity/announce/cid/${cid}`,
+			type: 'Announce',
+			actor: `${nconf.get('url')}/category/${cid}`,
+			to: [activitypub._constants.publicAddress],
+			cc: [`${nconf.get('url')}/category/${cid}/followers`],
+			object,
+		};
+	}));
+
 	res.status(200).json({
 		'@context': 'https://www.w3.org/ns/activitystreams',
-		type: 'OrderedCollection',
-		totalItems: 0,
-		orderedItems: [],
+		...collection,
 	});
 };