:sparkles: api

1 files changed, 162 insertions, 0 deletions

diff --git a/api/src/middlewares/RateLimit.ts b/api/src/middlewares/RateLimit.ts
new file mode 100644
index 00000000..c8fdeba2
--- /dev/null
+++ b/api/src/middlewares/RateLimit.ts
@@ -0,0 +1,162 @@
+import { db, MongooseCache, Bucket, Config } from "@fosscord/server-util";
+import { NextFunction, Request, Response, Router } from "express";
+import { getIpAdress } from "../util/ipAddress";
+import { API_PREFIX_TRAILING_SLASH } from "./Authentication";
+
+const Cache = new MongooseCache(
+	db.collection("ratelimits"),
+	[
+		// TODO: uncomment $match and fix error: not receiving change events
+		// { $match: { blocked: true } }
+	],
+	{ onlyEvents: false, array: true }
+);
+
+// Docs: https://discord.com/developers/docs/topics/rate-limits
+
+/*
+? bucket limit? Max actions/sec per bucket?
+
+TODO: ip rate limit
+TODO: user rate limit
+TODO: different rate limit for bots/user/oauth/webhook
+TODO: delay database requests to include multiple queries
+TODO: different for methods (GET/POST)
+TODO: bucket major parameters (channel_id, guild_id, webhook_id)
+TODO: use config values
+
+> IP addresses that make too many invalid HTTP requests are automatically and temporarily restricted from accessing the Discord API. Currently, this limit is 10,000 per 10 minutes. An invalid request is one that results in 401, 403, or 429 statuses.
+
+> All bots can make up to 50 requests per second to our API. This is independent of any individual rate limit on a route. If your bot gets big enough, based on its functionality, it may be impossible to stay below 50 requests per second during normal operations.
+
+*/
+
+export default function RateLimit(opts: {
+	bucket?: string;
+	window: number;
+	count: number;
+	bot?: number;
+	webhook?: number;
+	oauth?: number;
+	GET?: number;
+	MODIFY?: number;
+	error?: boolean;
+	success?: boolean;
+	onlyIp?: boolean;
+}): any {
+	Cache.init(); // will only initalize it once
+
+	return async (req: Request, res: Response, next: NextFunction): Promise<any> => {
+		const bucket_id = opts.bucket || req.originalUrl.replace(API_PREFIX_TRAILING_SLASH, "");
+		var user_id = getIpAdress(req);
+		if (!opts.onlyIp && req.user_id) user_id = req.user_id;
+
+		var max_hits = opts.count;
+		if (opts.bot && req.user_bot) max_hits = opts.bot;
+		if (opts.GET && ["GET", "OPTIONS", "HEAD"].includes(req.method)) max_hits = opts.GET;
+		else if (opts.MODIFY && ["POST", "DELETE", "PATCH", "PUT"].includes(req.method)) max_hits = opts.MODIFY;
+
+		const offender = Cache.data?.find((x: Bucket) => x.user_id == user_id && x.id === bucket_id) as Bucket | null;
+
+		if (offender && offender.blocked) {
+			const reset = offender.expires_at.getTime();
+			const resetAfterMs = reset - Date.now();
+			const resetAfterSec = resetAfterMs / 1000;
+			const global = bucket_id === "global";
+
+			if (resetAfterMs > 0) {
+				console.log("blocked bucket: " + bucket_id, { resetAfterMs });
+				return (
+					res
+						.status(429)
+						.set("X-RateLimit-Limit", `${max_hits}`)
+						.set("X-RateLimit-Remaining", "0")
+						.set("X-RateLimit-Reset", `${reset}`)
+						.set("X-RateLimit-Reset-After", `${resetAfterSec}`)
+						.set("X-RateLimit-Global", `${global}`)
+						.set("Retry-After", `${Math.ceil(resetAfterSec)}`)
+						.set("X-RateLimit-Bucket", `${bucket_id}`)
+						// TODO: error rate limit message translation
+						.send({ message: "You are being rate limited.", retry_after: resetAfterSec, global })
+				);
+			} else {
+				offender.hits = 0;
+				offender.expires_at = new Date(Date.now() + opts.window * 1000);
+				offender.blocked = false;
+				// mongodb ttl didn't update yet -> manually update/delete
+				db.collection("ratelimits").updateOne({ id: bucket_id, user_id }, { $set: offender });
+			}
+		}
+		next();
+		const hitRouteOpts = { bucket_id, user_id, max_hits, window: opts.window };
+
+		if (opts.error || opts.success) {
+			res.once("finish", () => {
+				// check if error and increment error rate limit
+				if (res.statusCode >= 400 && opts.error) {
+					return hitRoute(hitRouteOpts);
+				} else if (res.statusCode >= 200 && res.statusCode < 300 && opts.success) {
+					return hitRoute(hitRouteOpts);
+				}
+			});
+		} else {
+			return hitRoute(hitRouteOpts);
+		}
+	};
+}
+
+export function initRateLimits(app: Router) {
+	const { routes, global, ip, error } = Config.get().limits.rate;
+
+	app.use(
+		RateLimit({
+			bucket: "global",
+			onlyIp: true,
+			...ip
+		})
+	);
+	app.use(RateLimit({ bucket: "global", ...global }));
+	app.use(
+		RateLimit({
+			bucket: "error",
+			error: true,
+			onlyIp: true,
+			...error
+		})
+	);
+	app.use("/guilds/:id", RateLimit(routes.guild));
+	app.use("/webhooks/:id", RateLimit(routes.webhook));
+	app.use("/channels/:id", RateLimit(routes.channel));
+	app.use("/auth/login", RateLimit(routes.auth.login));
+	app.use("/auth/register", RateLimit({ onlyIp: true, success: true, ...routes.auth.register }));
+}
+
+function hitRoute(opts: { user_id: string; bucket_id: string; max_hits: number; window: number }) {
+	return db.collection("ratelimits").updateOne(
+		{ id: opts.bucket_id, user_id: opts.user_id },
+		[
+			{
+				$replaceRoot: {
+					newRoot: {
+						// similar to $setOnInsert
+						$mergeObjects: [
+							{
+								id: opts.bucket_id,
+								user_id: opts.user_id,
+								expires_at: new Date(Date.now() + opts.window * 1000)
+							},
+							"$$ROOT"
+						]
+					}
+				}
+			},
+			{
+				$set: {
+					hits: { $sum: [{ $ifNull: ["$hits", 0] }, 1] },
+					blocked: { $gte: ["$hits", opts.max_hits] }
+				}
+			}
+		],
+		{ upsert: true }
+	);
+}