ditto/packages/ditto/middleware/rateLimitMiddleware.ts

import { type DittoConf } from '@ditto/conf';
import { MiddlewareHandler } from '@hono/hono';
import { rateLimiter } from 'hono-rate-limiter';

/**
 * Rate limit middleware for Hono, based on [`hono-rate-limiter`](https://github.com/rhinobase/hono-rate-limiter).
 */
export function rateLimitMiddleware(limit: number, windowMs: number, includeHeaders?: boolean): MiddlewareHandler {
  // @ts-ignore Mismatched hono versions.
  return rateLimiter<{ Variables: { conf: DittoConf } }>({
    limit,
    windowMs,
    standardHeaders: includeHeaders,
    handler: (c) => {
      c.header('Cache-Control', 'no-store');
      return c.text('Too many requests, please try again later.', 429);
    },
    skip: (c) => {
      const { conf } = c.var;
      const ip = c.req.header('x-real-ip');
      return !ip || conf.ipWhitelist.includes(ip);
    },
    keyGenerator: (c) => c.req.header('x-real-ip')!,
  });
}