rateLimitMiddleware function

Middleware rateLimitMiddleware(RateLimitService service)

Implementation

Middleware rateLimitMiddleware(RateLimitService service) {
  return (EngineContext ctx, Next next) async {
    if (!service.enabled) {
      return await next();
    }

    final outcome = await service.check(ctx.request);
    if (outcome == null || outcome.allowed) {
      return await next();
    }

    final retryDuration = outcome.retryAfter;
    final retrySeconds = retryDuration.inSeconds <= 0
        ? (retryDuration.inMilliseconds > 0 ? 1 : 0)
        : retryDuration.inSeconds;
    ctx.response.statusCode = 429;
    ctx.response.headers.set('Retry-After', retrySeconds.toString());
    ctx.response.headers.set('Content-Type', 'application/json');
    ctx.response.write(
      '{"error":"too_many_requests","retry_after":$retrySeconds}',
    );
    ctx.abort();
    return ctx.response;
  };
}