cyg/FireflySoft.MultiRateLimit.AspNetCorev3.1.2

Introduction

Fireflysoft.RateLimit is a rate limiting library based on .Net standard. Its core is simple and lightweight, and can flexibly meet the rate limiting needs of many scenarios.

Features

• Multiple rate limiting algorithms: built-in fixed window, sliding window, leaky bucket, token bucket, and can be extended.
• Multiple counting storage: memory and Redis (including cluster).
• Distributed friendly: supports unified counting of distributed programs with Redis storage.
• Flexible rate limiting targets: each data can be extracted from the request to set rate limiting targets.
• Support rate limit penalty: the client can be locked for a period of time after the rate limit is triggered.
• Time window enhancement: support to the millisecond level; support starting from the starting point of time periods such as seconds, minutes, hours, dates, etc.
• Real-time tracking: the number of requests processed and the remaining allowed requests in the current counting cycle, as well as the reset time of the counting cycle.
• Dynamically change the rules: support the dynamic change of the rate limiting rules when the program is running.
• Custom error: you can customize the error code and error message after the current limit is triggered.
• Universality: in principle, it can meet any scenario that requires rate limiting.

Usage

The following code calls the rate-limit middleware from Startup.Configure:

public void ConfigureServices(IServiceCollection services)
{
    ...

    services.AddRateLimit(new IAlgorithm[2] {
            new InProcessFixedWindowAlgorithm(
            new[] {
                new FixedWindowRule()
                {
                    ExtractTarget = context =>
                    {
                        var httpContext= context as HttpContext;

                        // Through CDN
                        var ip = httpContext!.Request.Headers["Cdn-Src-Ip"].FirstOrDefault();
                        if (!string.IsNullOrEmpty(ip))
                            return ip;

                        // Through SLB
                        ip = httpContext!.Request.Headers["X-Forwarded-For"].FirstOrDefault();
                        if (!string.IsNullOrEmpty(ip))
                            return ip;

                        ip = httpContext!.Connection.RemoteIpAddress?.ToString();
                        return ip??"Anonymous-IP";
                    },
                    CheckRuleMatching = context =>
                    {
                        return true;
                    },
                    Name = "ClientIPRule",
                    LimitNumber = 30,
                    StatWindow = TimeSpan.FromSeconds(5)
                }
            }),
            new InProcessTokenBucketAlgorithm(
            new[] {
                new TokenBucketRule(4,4,TimeSpan.FromSeconds(5))
                {
                    ExtractTarget = context =>
                    {
                            var httpContext= context as HttpContext;
                        return httpContext!.Request.Path.Value;
                    },
                    CheckRuleMatching = context =>
                    {
                        return true;
                    },
                    Name="default limit rule",
                }
            })
        });

    ...
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    ...

    app.UseMultiRateLimit();

    ...
}