Upstash Ratelimit

bun add @upstash/ratelimit @upstash/redis

import { Ratelimit } from "@upstash/ratelimit";
import { Redis } from "@upstash/redis";

const ratelimit = new Ratelimit({
  redis: Redis.fromEnv(),
  limiter: Ratelimit.slidingWindow(10, "10 s"),
  analytics: true,
  prefix: "@redopjs/upstash-ratelimit",
});

import { McpError, McpErrorCode, Redop } from "@redopjs/redop";

new Redop({
  serverInfo: {
    name: "upstash-demo",
    version: "0.1.0",
  },
})
  .middleware(async ({ request, next }) => {
    const identifier =
      request.headers["x-user-id"] ??
      request.headers["x-forwarded-for"] ??
      request.ip ??
      "anonymous";

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

    if (pending) {
      void pending.catch(() => {});
    }

    if (!success) {
      throw new McpError(
        McpErrorCode.InvalidRequest,
        `Rate limit exceeded. Retry after ${Math.ceil(
          Math.max(reset - Date.now(), 0) / 1000
        )} seconds.`
      );
    }

    return next();
  })
  .tool("ping", {
    handler: () => ({ ok: true }),
  });

const app = new Redop<{ rateLimit: { remaining: number; reset: number } }>()
  .derive(async ({ request }) => {
    const identifier =
      request.headers["x-user-id"] ?? request.ip ?? "anonymous";

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

    if (pending) {
      void pending.catch(() => {});
    }

    if (!success) {
      throw new Error("Too many requests");
    }

    return {
      rateLimit: { remaining, reset },
    };
  });