I have to implement rate limiting to public endpoints using .Net 7 new Rate limiting Middleware.
For now I’ve settled on a fixedWindow rate limiter.
I’ve found many differents implementations online, but the only ones I found implementing any kind of filtering on IP/Client are using the globalLimiter which I dont want.
I have many endpoints and I want 2 different limiters on 2 of my public endpoints.
What I want is a mix of the 2 following implementation, which allows me to name the policy to implement it on only the endpoints, and the rate limiting to be per/client.

2 different policies I can assign to each of my endpoints:

builder.Services.AddRateLimiter(options =>
{
    options.AddFixedWindowLimiter("myRateLimiter1", options =>
    {
        options.AutoReplenishment = true;
        options.PermitLimit = 1;
        options.Window = TimeSpan.FromSeconds(30);
    });
    options.AddFixedWindowLimiter("myRateLimiter12", options =>
    {
        options.AutoReplenishment = true;
        options.PermitLimit = 1;
        options.Window = TimeSpan.FromSeconds(30);
    });
});

Filtering clients that is implemented globally

builder.Services.AddRateLimiter(options =>
{
    options.GlobalLimiter = PartitionedRateLimiter.Create<HttpContext, string>(httpContext =>
        RateLimitPartition.GetFixedWindowLimiter(
            partitionKey: httpContext.User.Identity?.Name ?? httpContext.Request.Headers.Host.ToString(),
            factory: partition => new FixedWindowRateLimiterOptions
            {
                AutoReplenishment = true,
                PermitLimit = 1,
                QueueLimit = 0,
                Window = TimeSpan.FromSeconds(30)
            }));
});

I also found this implementation that does the job but cant find how to add filtering either

app.UseRateLimiter(new RateLimiterOptions
{
    OnRejected = (context, _) =>
    {
        if (context.Lease.TryGetMetadata(MetadataName.RetryAfter, out var retryAfter))
        {
            context.HttpContext.Response.Headers.RetryAfter =
                ((int)retryAfter.TotalSeconds).ToString(NumberFormatInfo.InvariantInfo);

            app.Logger.LogWarning("Rate limit exceeded, retry after {RetryAfter} seconds", retryAfter.TotalSeconds);
        }

        context.HttpContext.Response.StatusCode = StatusCodes.Status429TooManyRequests;

        return new ValueTask();
    }
}
.AddFixedWindowLimiter("myRateLimiter1", options =>
{
    options.AutoReplenishment = true;
    options.PermitLimit = 1;
    options.Window = TimeSpan.FromSeconds(10);
    options.QueueLimit = 0;
}).AddFixedWindowLimiter("myRateLimiter2", options =>
{
    options.AutoReplenishment = true;
    options.PermitLimit = 1;
    options.Window = TimeSpan.FromSeconds(10);
    options.QueueLimit = 0;
}));

>Solution :

Add your limiters via RateLimiterOptions.AddPolicy:

builder.Services.AddRateLimiter(options =>
{
    options.AddPolicy("myRateLimiter1", context => RateLimitPartition.GetFixedWindowLimiter(
        partitionKey: context.User.Identity?.Name ?? context.Request.Headers.Host.ToString(),
        factory: partition => new FixedWindowRateLimiterOptions
        {
            AutoReplenishment = true,
            PermitLimit = 1,
            QueueLimit = 0,
            Window = TimeSpan.FromSeconds(30)
        }));
    // and the second one
});