From 13c048a5153682711cb4a7b04d768ebdbed86b83 Mon Sep 17 00:00:00 2001
From: Julian Lam <julian@nodebb.org>
Date: Thu, 17 Oct 2024 13:45:56 -0400
Subject: [PATCH] feat: normalization middleware to ensure incoming objects'
 data types are as expected (simplifies later logic)

---
 src/middleware/activitypub.js | 15 +++++++++++++++
 src/routes/activitypub.js     |  1 +
 2 files changed, 16 insertions(+)

diff --git a/src/middleware/activitypub.js b/src/middleware/activitypub.js
index f7183f6f36..8913339ea4 100644
--- a/src/middleware/activitypub.js
+++ b/src/middleware/activitypub.js
@@ -137,6 +137,21 @@ middleware.resolveObjects = async function (req, res, next) {
 	next();
 };
 
+middleware.normalize = async function (req, res, next) {
+	// Normalizes the received data structure
+	const { body } = req;
+	const { object } = body;
+
+	// Ensure `to` and `cc` are arrays in the object
+	['to', 'cc'].forEach((prop) => {
+		if (object[prop] && typeof object[prop] === 'string') {
+			object[prop] = [object[prop]];
+		}
+	});
+
+	next();
+};
+
 middleware.configureResponse = async function (req, res, next) {
 	res.header('Content-Type', 'application/activity+json');
 	next();
diff --git a/src/routes/activitypub.js b/src/routes/activitypub.js
index 9a378b41b1..dadff0bdf4 100644
--- a/src/routes/activitypub.js
+++ b/src/routes/activitypub.js
@@ -21,6 +21,7 @@ module.exports = function (app, middleware, controllers) {
 	const inboxMiddlewares = [
 		middleware.activitypub.assertPayload,
 		middleware.activitypub.resolveObjects,
+		middleware.activitypub.normalize,
 	];
 
 	app.get('/actor', middlewares, controllers.activitypub.actors.application);