feat: login when adding to guild, then redirect to its settings

src/http.js

@@ -40,11 +40,12 @@ module.exports = async client => {
 			},
 		},
 		generateStateFunction: req => {
-			const state = randomBytes(12).toString('hex');
+			const state = randomBytes(8).toString('hex');
 			fastify.states.set(state, req.query.r);
 			return state;
 		},
 		name: 'discord',
+		redirectStateCookieName: 'oauth2-redirect-state',
 		scope: ['applications.commands.permissions.update', 'guilds', 'identify'],
 		startRedirectPath: '/auth/login',
 	});

src/routes/auth/callback.js

@@ -13,8 +13,7 @@ module.exports.get = () => ({
 			headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
 			method: 'POST',
 		})).json();
-		const redirect = this.states.get(req.query.state) || '/';
+
-		this.states.delete(req.query.state);
 		const user = await (await fetch('https://discordapp.com/api/users/@me', { headers: { 'Authorization': `Bearer ${data.access_token}` } })).json();
 		const token = this.jwt.sign({
 			accessToken: data.access_token,
@@ -24,6 +23,11 @@ module.exports.get = () => ({
 			locale: user.locale,
 			username: user.username,
 		});
+
+		// note: if data.guild is present, guild_id and permissions should also be in req.query
+		const redirect = this.states.get(req.query.state) || (data.guild?.id && `/settings/${data.guild?.id}`) || '/';
+		this.states.delete(req.query.state);
+
 		res.setCookie('token', token, {
 			domain,
 			httpOnly: true,

src/routes/invite.js

@@ -0,0 +1,29 @@
+const { randomBytes } = require('crypto');
+
+module.exports.get = () => ({
+	handler: async function (req, res) {
+		const { client } = req.routeOptions.config;
+
+		const state = randomBytes(8).toString('hex');
+		this.states.set(state, null);
+
+		const url = new URL('https://discord.com/oauth2/authorize');
+		url.searchParams.set('response_type', 'code');
+		url.searchParams.set('client_id', client.user.id);
+		url.searchParams.set('prompt', 'none');
+		url.searchParams.set('redirect_uri', `${process.env.HTTP_EXTERNAL}/auth/callback`); // window.location.origin
+		url.searchParams.set('scope', 'applications.commands applications.commands.permissions.update bot guilds identify');
+		url.searchParams.set('permissions', '268561488');
+
+		if (req.query.guild) {
+			url.searchParams.set('guild_id', req.query.guild);
+			url.searchParams.set('disable_guild_select', 'true');
+		}
+
+		res.setCookie('oauth2-redirect-state', state, {
+			httpOnly: true,
+			sameSite: 'lax',
+		});
+		res.redirect(url.toString());
+	},
+});