middleware.ts

import {
  type NextFetchEvent,
  type NextRequest,
  NextResponse,
} from "next/server";
import { Ratelimit } from "@upstash/ratelimit";
import { Redis } from "@upstash/redis";

const redis = new Redis({
  url: process.env.UPSTASH_REDIS_REST_URL || "",
  token: process.env.UPSTASH_REDIS_REST_TOKEN || "",
});

const ratelimit = new Ratelimit({
  redis: redis,
  limiter: Ratelimit.slidingWindow(5, "10 s"),
});

export default async function middleware(
  request: NextRequest,
  event: NextFetchEvent
) {
  const ip = request.ip ?? "127.0.0.1";

  const { success, pending, limit, reset, remaining } = await ratelimit.limit(
    String(ip)
  );

  event.waitUntil(pending);

  const res = success
    ? NextResponse.next()
    : NextResponse.redirect(new URL("/404", request.url));

  res.headers.set("X-RateLimit-Limit", limit.toString());
  res.headers.set("X-RateLimit-Remaining", remaining.toString());
  res.headers.set("X-RateLimit-Reset", reset.toString());
  return res;
}

export const config = {
  matcher: "/api/:path*",
};