PIR_Lab_1/Middleware/RateLimitingMiddleware.cs - master - Lexus_666/PIR_Lab_3

PIR_Lab_1/Middleware/RateLimitingMiddleware.cs

59 строк2 KB

Lexus_666

CORS setup

24 дек 2025, 00:32

24 дек 2025, 00:3281bee9f

namespace PIR_Lab_1.Middleware;

public class RateLimitingMiddleware
{
    private readonly RequestDelegate _next;
    private readonly Dictionary<string, (int Count, DateTime WindowStart)> _requestCounts = new();
    private const int Limit = 15;
    private readonly TimeSpan _window = TimeSpan.FromMinutes(1);

    public RateLimitingMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        if (context.Request.Path.StartsWithSegments("/api/internal"))
        {
            await _next(context);
            return;
        }

        var clientId = GetClientId(context);
        var now = DateTime.UtcNow;

        if (!_requestCounts.TryGetValue(clientId, out var clientData))
        {
            clientData = (0, now);
        }

        if (now - clientData.WindowStart > _window)
        {
            clientData = (0, now);
        }

        if (clientData.Count >= Limit)
        {
            context.Response.StatusCode = StatusCodes.Status429TooManyRequests;
            var retryAfter = (int)(clientData.WindowStart.Add(_window) - now).TotalSeconds;
            context.Response.Headers.RetryAfter = retryAfter.ToString();
            await context.Response.WriteAsync("Rate limit exceeded");
            return;
        }

        clientData.Count++;
        _requestCounts[clientId] = clientData;

        context.Response.Headers["X-RateLimit-Limit"] = Limit.ToString();
        context.Response.Headers["X-RateLimit-Remaining"] = (Limit - clientData.Count).ToString();
        context.Response.Headers["X-RateLimit-Reset"] = clientData.WindowStart.Add(_window).ToString("R");

        await _next(context);
    }

    private static string GetClientId(HttpContext context)
    {
        return context.Connection.RemoteIpAddress?.ToString() ?? "unknown";
    }
}