From 41692b11ff53ce230a21998d9847839296b9b5c4 Mon Sep 17 00:00:00 2001
From: Bea <beanie@theargo.space>
Date: Fri, 20 Mar 2026 13:54:19 +0000
Subject: [PATCH] feat(m2d): support MSC4144 per-message profiles

Override webhook username and avatar_url from m.per_message_profile
(and unstable com.beeper.per_message_profile) when present.
The stable key takes priority over the unstable prefix.
---
 src/m2d/converters/event-to-message.js      |   4 +
 src/m2d/converters/event-to-message.test.js | 102 ++++++++++++++++++++
 2 files changed, 106 insertions(+)

diff --git a/src/m2d/converters/event-to-message.js b/src/m2d/converters/event-to-message.js
index 1b23787..7fdbb15 100644
--- a/src/m2d/converters/event-to-message.js
+++ b/src/m2d/converters/event-to-message.js
@@ -557,6 +557,10 @@ async function eventToMessage(event, guild, channel, di) {
 	const member = await getMemberFromCacheOrHomeserver(event.room_id, event.sender, di?.api)
 	if (member.displayname) displayName = member.displayname
 	if (member.avatar_url) avatarURL = mxUtils.getPublicUrlForMxc(member.avatar_url)
+	// Override display name and avatar from MSC4144 per-message profile if present
+	const perMessageProfile = event.content["m.per_message_profile"] || event.content["com.beeper.per_message_profile"]
+	if (perMessageProfile?.displayname) displayName = perMessageProfile.displayname
+	if (perMessageProfile?.avatar_url) avatarURL = mxUtils.getPublicUrlForMxc(perMessageProfile.avatar_url)
 	// If the display name is too long to be put into the webhook (80 characters is the maximum),
 	// put the excess characters into displayNameRunoff, later to be put at the top of the message
 	let [displayNameShortened, displayNameRunoff] = splitDisplayName(displayName)
diff --git a/src/m2d/converters/event-to-message.test.js b/src/m2d/converters/event-to-message.test.js
index 1c263b4..b283d82 100644
--- a/src/m2d/converters/event-to-message.test.js
+++ b/src/m2d/converters/event-to-message.test.js
@@ -5526,6 +5526,108 @@ test("event2message: known and unknown emojis in the end are used for sprite she
 	)
 })
 
+test("event2message: m.per_message_profile overrides displayname and avatar_url", async t => {
+	t.deepEqual(
+		await eventToMessage({
+			type: "m.room.message",
+			sender: "@cadence:cadence.moe",
+			content: {
+				msgtype: "m.text",
+				body: "hello from a custom profile",
+				"m.per_message_profile": {
+					id: "custom-id",
+					displayname: "Custom Name",
+					avatar_url: "mxc://maunium.net/hgXsKqlmRfpKvCZdUoWDkFQo"
+				}
+			},
+			event_id: "$g07oYSZFWBkxohNEfywldwgcWj1hbhDzQ1sBAKvqOOU",
+			room_id: "!kLRqKKUQXcibIMtOpl:cadence.moe"
+		}),
+		{
+			ensureJoined: [],
+			messagesToDelete: [],
+			messagesToEdit: [],
+			messagesToSend: [{
+				username: "Custom Name",
+				content: "hello from a custom profile",
+				avatar_url: "https://bridge.example.org/download/matrix/maunium.net/hgXsKqlmRfpKvCZdUoWDkFQo",
+				allowed_mentions: {
+					parse: ["users", "roles"]
+				}
+			}]
+		}
+	)
+})
+
+test("event2message: com.beeper.per_message_profile (unstable prefix) overrides displayname and avatar_url", async t => {
+	t.deepEqual(
+		await eventToMessage({
+			type: "m.room.message",
+			sender: "@cadence:cadence.moe",
+			content: {
+				msgtype: "m.text",
+				body: "hello from unstable profile",
+				"com.beeper.per_message_profile": {
+					id: "custom-id",
+					displayname: "Unstable Name",
+					avatar_url: "mxc://maunium.net/hgXsKqlmRfpKvCZdUoWDkFQo"
+				}
+			},
+			event_id: "$g07oYSZFWBkxohNEfywldwgcWj1hbhDzQ1sBAKvqOOU",
+			room_id: "!kLRqKKUQXcibIMtOpl:cadence.moe"
+		}),
+		{
+			ensureJoined: [],
+			messagesToDelete: [],
+			messagesToEdit: [],
+			messagesToSend: [{
+				username: "Unstable Name",
+				content: "hello from unstable profile",
+				avatar_url: "https://bridge.example.org/download/matrix/maunium.net/hgXsKqlmRfpKvCZdUoWDkFQo",
+				allowed_mentions: {
+					parse: ["users", "roles"]
+				}
+			}]
+		}
+	)
+})
+
+test("event2message: m.per_message_profile takes priority over com.beeper.per_message_profile", async t => {
+	t.deepEqual(
+		await eventToMessage({
+			type: "m.room.message",
+			sender: "@cadence:cadence.moe",
+			content: {
+				msgtype: "m.text",
+				body: "stable wins",
+				"m.per_message_profile": {
+					id: "stable-id",
+					displayname: "Stable Name"
+				},
+				"com.beeper.per_message_profile": {
+					id: "unstable-id",
+					displayname: "Unstable Name"
+				}
+			},
+			event_id: "$g07oYSZFWBkxohNEfywldwgcWj1hbhDzQ1sBAKvqOOU",
+			room_id: "!kLRqKKUQXcibIMtOpl:cadence.moe"
+		}),
+		{
+			ensureJoined: [],
+			messagesToDelete: [],
+			messagesToEdit: [],
+			messagesToSend: [{
+				username: "Stable Name",
+				content: "stable wins",
+				avatar_url: undefined,
+				allowed_mentions: {
+					parse: ["users", "roles"]
+				}
+			}]
+		}
+	)
+})
+
 test("event2message: all unknown chess emojis are used for sprite sheet", async t => {
 	t.deepEqual(
 		await eventToMessage({