Rate Limiter Library

Introduction

This library provides a distributed rate limiting solution, designed to manage and throttle API requests. It supports multiple strategies such as fixed window and token bucket rate limiting, offering flexibility for per-user, per-IP, or per-service rate limiting. The library is optimized for high scalability and performance in distributed environments.

Features

• Supports Fixed Window and Token Bucket rate limiting strategies.
• Flexible configuration for per-user, per-IP, or per-service rate limiting.
• Distributed design using Redis for scalability.
• Handles burst traffic (in Token Bucket strategy).
• Provides relevant HTTP headers to indicate capacity status.

Documentation

Rate Limiting Strategies

• Fixed Window Strategy
• Token Bucket Strategy

Core Components

• Enable Rate Limiting Attribute
• Disable Rate Limiting Attribute
• Rate Limiting Middleware

Advanced Topics

• Rate Limiter Strategy Base
• Rate Limiter Extensions
• IRateLimitCounterStore Interface
• Rate Limiter Policy Registry

Example

Here is a simple example of how to configure the rate limiter in a .NET application:

builder.Services.AddSingleton<IRateLimitCounterStore, InMemoryRateLimitCounterStore>();
builder.Services.AddRateLimiter(options =>
{
    options.AddFixedWindowPolicy("fixed", fixedWindowOptions =>
    {
        fixedWindowOptions.PermitLimit = 20;
        fixedWindowOptions.Window = TimeSpan.FromSeconds(1);
        fixedWindowOptions.KeyGenerator = context => context.Request.Headers["User-Identity"].ToString() ??  $"anonymous";
    })
    .MarkAsDefault();

    options.AddTokenBucketPolicy("token", tokenBucketOptions =>
    {
        tokenBucketOptions.MaxRequestsPerSecond = 20;
        tokenBucketOptions.BurstCapacity = 100;
    })
});

var app = builder.Build();

app.UseMiddleware<RateLimitingMiddleware>()