m2d reactions (untested)

d2m/actions/add-reaction.js

@@ -1,6 +1,6 @@
 // @ts-check
 
-const assert = require("assert")
+const assert = require("assert").strict
 
 const passthrough = require("../../passthrough")
 const { discord, sync, db } = passthrough
@@ -18,7 +18,7 @@ async function addReaction(data) {
    const user = data.member?.user
    assert.ok(user && user.username)
    const parentID = db.prepare("SELECT event_id FROM event_message WHERE message_id = ? AND part = 0").pluck().get(data.message_id) // 0 = primary
-   if (!parentID) return // TODO: how to handle reactions for unbridged messages? is there anything I can do?
+   if (!parentID) return // Nothing can be done if the parent message was never bridged.
    assert.equal(typeof parentID, "string")
 	const roomID = await createRoom.ensureRoom(data.channel_id)
 	const senderMxid = await registerUser.ensureSimJoined(user, roomID)

m2d/actions/add-reaction.js

@@ -0,0 +1,25 @@
+// @ts-check
+
+const assert = require("assert").strict
+const Ty = require("../../types")
+
+const passthrough = require("../../passthrough")
+const { discord, sync, db } = passthrough
+
+/**
+ * @param {Ty.Event.Outer<Ty.Event.M_Reaction>} event
+ */
+async function addReaction(event) {
+	const channelID = db.prepare("SELECT channel_id FROM channel_room WHERE room_id = ?").pluck().get(event.room_id)
+	if (!channelID) return // We just assume the bridge has already been created
+	const messageID = db.prepare("SELECT message_id FROM event_message WHERE event_id = ? AND part = 0").pluck().get(event.content["m.relates_to"].event_id) // 0 = primary
+	if (!messageID) return // Nothing can be done if the parent message was never bridged.
+
+	// no need to sync the matrix member to the other side. but if I did need to, this is where I'd do it
+
+	const emoji = event.content["m.relates_to"].key // TODO: handle custom text or emoji reactions
+
+	return discord.snow.channel.createReaction(channelID, messageID, emoji)
+}
+
+module.exports.addReaction = addReaction

m2d/converters/event-to-message.js

@@ -1,5 +1,6 @@
 // @ts-check
 
+const Ty = require("../../types")
 const DiscordTypes = require("discord-api-types/v10")
 const markdown = require("discord-markdown")
 
@@ -9,7 +10,7 @@ const { sync, db, discord } = passthrough
 const file = sync.require("../../matrix/file")
 
 /**
- * @param {import("../../types").Event.Outer<import("../../types").Event.M_Room_Message>} event
+ * @param {Ty.Event.Outer<Ty.Event.M_Room_Message>} event
  */
 function eventToMessage(event) {
 	/** @type {(DiscordTypes.RESTPostAPIWebhookWithTokenJSONBody & {files?: {name: string, file: Buffer}[]})[]} */

m2d/event-dispatcher.js

@@ -4,19 +4,30 @@
  * Grab Matrix events we care about, check them, and bridge them.
  */
 
+const Ty = require("../types")
 const {sync, as} = require("../passthrough")
 
 /** @type {import("./actions/send-event")} */
 const sendEvent = sync.require("./actions/send-event")
+/** @type {import("./actions/add-reaction")} */
+const addReaction = sync.require("./actions/add-reaction")
 /** @type {import("./converters/utils")} */
 const utils = sync.require("./converters/utils")
 
-
 sync.addTemporaryListener(as, "type:m.room.message",
 /**
- * @param {import("../types").Event.Outer<import("../types").Event.M_Room_Message>} event it is a m.room.message because that's what this listener is filtering for
+ * @param {Ty.Event.Outer<Ty.Event.M_Room_Message>} event it is a m.room.message because that's what this listener is filtering for
  */
 async event => {
 	if (utils.eventSenderIsFromDiscord(event.sender)) return
 	const messageResponses = await sendEvent.sendEvent(event)
 })
+
+sync.addTemporaryListener(as, "type:m.reaction",
+/**
+ * @param {Ty.Event.Outer<Ty.Event.M_Reaction>} event it is a m.reaction because that's what this listener is filtering for
+ */
+async event => {
+	if (utils.eventSenderIsFromDiscord(event.sender)) return
+	await addReaction.addReaction(event)
+})

matrix/api.js

@@ -1,5 +1,6 @@
 // @ts-check
 
+const Ty = require("../types")
 const assert = require("assert")
 
 const passthrough = require("../passthrough")
@@ -25,7 +26,7 @@ function path(p, mxid) {
 
 /**
  * @param {string} username
- * @returns {Promise<import("../types").R.Registered>}
+ * @returns {Promise<Ty.R.Registered>}
  */
 function register(username) {
    console.log(`[api] register: ${username}`)
@@ -40,7 +41,7 @@ function register(username) {
  */
 async function createRoom(content) {
    console.log(`[api] create room:`, content)
-   /** @type {import("../types").R.RoomCreated} */
+   /** @type {Ty.R.RoomCreated} */
    const root = await mreq.mreq("POST", "/client/v3/createRoom", content)
    return root.room_id
 }
@@ -49,7 +50,7 @@ async function createRoom(content) {
  * @returns {Promise<string>} room ID
  */
 async function joinRoom(roomIDOrAlias, mxid) {
-   /** @type {import("../types").R.RoomJoined} */
+   /** @type {Ty.R.RoomJoined} */
    const root = await mreq.mreq("POST", path(`/client/v3/join/${roomIDOrAlias}`, mxid))
    return root.room_id
 }
@@ -66,7 +67,7 @@ async function leaveRoom(roomID, mxid) {
 
 /**
  * @param {string} roomID
- * @returns {Promise<import("../types").Event.BaseStateEvent[]>}
+ * @returns {Promise<Ty.Event.BaseStateEvent[]>}
  */
 function getAllState(roomID) {
    return mreq.mreq("GET", `/client/v3/rooms/${roomID}/state`)
@@ -83,14 +84,14 @@ async function sendState(roomID, type, stateKey, content, mxid) {
    console.log(`[api] state: ${roomID}: ${type}/${stateKey}`)
    assert.ok(type)
    assert.ok(typeof stateKey === "string")
-   /** @type {import("../types").R.EventSent} */
+   /** @type {Ty.R.EventSent} */
    const root = await mreq.mreq("PUT", path(`/client/v3/rooms/${roomID}/state/${type}/${stateKey}`, mxid), content)
    return root.event_id
 }
 
 async function sendEvent(roomID, type, content, mxid) {
    console.log(`[api] event to ${roomID} as ${mxid || "default sim"}`)
-   /** @type {import("../types").R.EventSent} */
+   /** @type {Ty.R.EventSent} */
    const root = await mreq.mreq("PUT", path(`/client/v3/rooms/${roomID}/send/${type}/${makeTxnId.makeTxnId()}`, mxid), content)
    return root.event_id
 }

types.d.ts

@@ -62,6 +62,14 @@ namespace Event {
 		display_name?: string
 		avatar_url?: string
 	}
+
+	export type M_Reaction = {
+		"m.relates_to": {
+			rel_type: "m.annotation"
+			event_id: string // the event that was reacted to
+			key: string // the unicode emoji, mxc uri, or reaction text
+		}
+	}
 }
 
 namespace R {

types.js

@@ -0,0 +1 @@
+module.exports = {}