Support persistent Matrix sims for webhooks

src/d2m/actions/register-webhook-user.js

@@ -0,0 +1,146 @@
+// @ts-check
+
+const assert = require("assert")
+const {reg} = require("../../matrix/read-registration")
+const Ty = require("../../types")
+
+const passthrough = require("../../passthrough")
+const {sync, db, select, from} = passthrough
+/** @type {import("../../matrix/api")} */
+const api = sync.require("../../matrix/api")
+/** @type {import("../../matrix/file")} */
+const file = sync.require("../../matrix/file")
+/** @type {import("./register-user")} */
+const registerUser = sync.require("./register-user")
+/** @type {import("../converters/user-to-mxid")} */
+const userToMxid = sync.require("../converters/user-to-mxid")
+
+/**
+ * A sim is an account that is being simulated by the bridge to copy events from the other side.
+ * @param {string} fakeUserID
+ * @param {Ty.WebhookAuthor} author
+ * @returns mxid
+ */
+async function createSim(fakeUserID, author) {
+	// Choose sim name
+	const simName = userToMxid.webhookAuthorToSimName(author)
+	const localpart = reg.ooye.namespace_prefix + simName
+	const mxid = `@${localpart}:${reg.ooye.server_name}`
+
+	// Save chosen name in the database forever
+	db.prepare("INSERT INTO sim (user_id, username, sim_name, mxid) VALUES (?, ?, ?, ?)").run(fakeUserID, author.username, simName, mxid)
+
+	// Register matrix user with that name
+	try {
+		await api.register(localpart)
+	} catch (e) {
+		// If user creation fails, manually undo the database change. Still isn't perfect, but should help.
+		// (I would prefer a transaction, but it's not safe to leave transactions open across event loop ticks.)
+		db.prepare("DELETE FROM sim WHERE user_id = ?").run(fakeUserID)
+		throw e
+	}
+	return mxid
+}
+
+/**
+ * Ensure a sim is registered for the user.
+ * If there is already a sim, use that one. If there isn't one yet, register a new sim.
+ * @param {string} fakeUserID
+ * @param {Ty.WebhookAuthor} author
+ * @returns {Promise<string>} mxid
+ */
+async function ensureSim(fakeUserID, author) {
+	let mxid = null
+	const existing = select("sim", "mxid", {user_id: fakeUserID}).pluck().get()
+	if (existing) {
+		mxid = existing
+	} else {
+		mxid = await createSim(fakeUserID, author)
+	}
+	return mxid
+}
+
+/**
+ * Ensure a sim is registered for the user and is joined to the room.
+ * @param {string} fakeUserID
+ * @param {Ty.WebhookAuthor} author
+ * @param {string} roomID
+ * @returns {Promise<string>} mxid
+ */
+async function ensureSimJoined(fakeUserID, author, roomID) {
+	// Ensure room ID is really an ID, not an alias
+	assert.ok(roomID[0] === "!")
+
+	// Ensure user
+	const mxid = await ensureSim(fakeUserID, author)
+
+	// Ensure joined
+	const existing = select("sim_member", "mxid", {room_id: roomID, mxid}).pluck().get()
+	if (!existing) {
+		try {
+			await api.inviteToRoom(roomID, mxid)
+			await api.joinRoom(roomID, mxid)
+		} catch (e) {
+			if (e.message.includes("is already in the room.")) {
+				// Sweet!
+			} else {
+				throw e
+			}
+		}
+		db.prepare("INSERT OR IGNORE INTO sim_member (room_id, mxid) VALUES (?, ?)").run(roomID, mxid)
+	}
+	return mxid
+}
+
+/**
+ * Generate profile data based on webhook displayname and configured avatar.
+ * @param {Ty.WebhookAuthor} author
+ */
+async function authorToStateContent(author) {
+	// We prefer to use the member's avatar URL data since the image upload can be cached across channels,
+	// unlike the userAvatar URL which is unique per channel, due to the webhook ID being in the URL.
+	const avatar = file.userAvatar(author)
+
+	const content = {
+		displayname: author.username,
+		membership: "join",
+	}
+	if (avatar) content.avatar_url = await file.uploadDiscordFileToMxc(avatar)
+
+	return content
+}
+
+/**
+ * Sync profile data for a sim webhook user. This function follows the following process:
+ * 1. Create and join the sim to the room if needed
+ * 2. Make an object of what the new room member state content would be, including uploading the profile picture if it hasn't been done before
+ * 3. Compare against the previously known state content, which is helpfully stored in the database
+ * 4. If the state content has changed, send it to Matrix and update it in the database for next time
+ * @param {Ty.WebhookAuthor} author for profile data
+ * @param {string} roomID room to join member to
+ * @param {boolean} shouldActuallySync whether to actually sync updated user data or just ensure it's joined
+ * @returns {Promise<string>} mxid of the updated sim
+ */
+async function syncUser(author, roomID, shouldActuallySync) {
+	const fakeUserID = userToMxid.webhookAuthorToFakeUserID(author)
+
+	// Create and join the sim to the room if needed
+	const mxid = await ensureSimJoined(fakeUserID, author, roomID)
+
+	if (shouldActuallySync) {
+		// Build current profile data
+		const content = await authorToStateContent(author)
+		const currentHash = registerUser._hashProfileContent(content, 0)
+		const existingHash = select("sim_member", "hashed_profile_content", {room_id: roomID, mxid}).safeIntegers().pluck().get()
+
+		// Only do the actual sync if the hash has changed since we last looked
+		if (existingHash !== currentHash) {
+			await api.sendState(roomID, "m.room.member", mxid, content, mxid)
+			db.prepare("UPDATE sim_member SET hashed_profile_content = ? WHERE room_id = ? AND mxid = ?").run(currentHash, roomID, mxid)
+		}
+	}
+
+	return mxid
+}
+
+module.exports.syncUser = syncUser