feat: implement discourse sso

nuxt.config.ts

@@ -48,6 +48,7 @@ export default defineNuxtConfig({
 		discordGuildId: '',
 		discordTesterRoleId: '',
 		discordSupporterRoleId: '',
+		discourseSsoSecret: '',
 
 		public: {
 			apiBase: 'https://api.pretendo.cc',

server/routes/blog/account/sso/discourse.get.ts

@@ -0,0 +1,65 @@
+import { GetUserDataResponse } from "@pretendonetwork/grpc/api/get_user_data_rpc";
+import { createHmac } from "node:crypto";
+
+function getDicourseSignature(secret: string, payload: string) {
+	return createHmac('sha256', secret).update(payload).digest('hex');
+}
+
+export default defineEventHandler(async (event) => {
+	const config = useRuntimeConfig(event);
+	const secret = config.discourseSsoSecret;
+	if (!secret) {
+		return sendRedirect(event, '/');
+	}
+
+	const query = getQuery(event);
+	const accessTokenCookie = getCookie(event, 'access_token');
+	if (!query.sso) {
+		return sendRedirect(event, '/');
+	}
+
+	const signature = getDicourseSignature(secret, query.sso.toString());
+	if (!query.sig || signature !== query.sig) {
+		return sendRedirect(event, '/');
+	}
+
+	const payload = new URLSearchParams(Buffer.from(query.sso.toString(), 'base64').toString());
+	const nonce = payload.get('nonce');
+	const returnSsoUrl = payload.get('return_sso_url');
+	if (!nonce || !returnSsoUrl) {
+		return sendRedirect(event, '/');
+	}
+
+	let userData: GetUserDataResponse | null = null;
+	if (accessTokenCookie) {
+		const grpc = useApiGrpcWithToken(event, accessTokenCookie);
+		userData = await grpc.getUserData({});
+	}
+	if (!userData) {
+		const redirectUrlParams = new URLSearchParams();
+		redirectUrlParams.append('sso', query.sso.toString());
+		redirectUrlParams.append('sig', query.sig.toString());
+		const redirect = `/sso/discourse?${redirectUrlParams}`;
+
+		const urlParams = new URLSearchParams();
+		urlParams.append('redirect', redirect)
+		return sendRedirect(event, `/login?${urlParams}`); // Not logged in, redirect to login
+	}
+
+	// Build final payload for discourse
+	const returnPayload = new URLSearchParams({
+		nonce: nonce,
+		external_id: userData.pid.toString(),
+		email: `${userData.pid}@invalid.com`, // Don't change, used by other systems
+		username: userData.username,
+		name: userData.username,
+		avatar_url: `https://r2-cdn.pretendo.cc/mii/${userData.pid}/normal_face.png`,
+		avatar_force_update: 'true'
+	});
+	const encodedReturnPayload = Buffer.from(returnPayload.toString()).toString('base64');
+
+	const url = new URL(returnSsoUrl);
+	url.searchParams.append('sso', encodedReturnPayload);
+	url.searchParams.append('sig', getDicourseSignature(secret, encodedReturnPayload));
+	return sendRedirect(event, url.toString());
+});