学习C#调用AspNetCoreRateLimit包限制客户端访问次数（3：动态配置）

C#调用AspNetCoreRateLimit限流，如果在appsettings.json中设置IpRateLimiting和IpRateLimitPolicies，则在项目启动时从appsettings.json中加载并应用规则，但在运行过程中没有办法调整规则，此时可以使用IpRateLimitOptions和IIpPolicyStore接口获取并调整限流规则，也可以基于这两个接口将限流规则保存到数据库或第三方缓存，或者从数据库或第三方缓存中读取并应用缓存
IpRateLimitOptions接口维护全局行为与通用规则，对应appsettings.json的IpRateLimiting配置，IIpPolicyStore接口维护特定IP或IP段的限流规则，对应appsettings.json的IpRateLimitPolicies配置。IpRateLimitOptions接口继承自RateLimitOptions类，其内的属性与appsettings.json的IpRateLimiting配置属性大致相同，可以参照之前的文章设置参数，而IIpPolicyStore接口继承自IRateLimitStore，需要调用GetAsync获取IpRateLimitPolicies策略对象，调整策略数据后再调用SetAsync保存IpRateLimitPolicies策略对象。
根据参考文献1的示例代码，结合参考文献2及DeepSeek，编写了动态配置的示例代码，经过验证调用AddGeneralRule动态调整通用规则运行正常，但是添加AddIpRule函数添加的特定规则没有生效，经过调试新增的规则已经保存到_ipPolicyStore内，且代码逻辑和参考文献及大模型给出的代码相同，暂时不清楚不生效的原因。

csharp 复制代码

public class RateLimitController : ControllerBase
{ 
    private readonly IpRateLimitOptions _options;
    private readonly IIpPolicyStore _ipPolicyStore;

    public RateLimitController(IOptions<IpRateLimitOptions> optionsAccessor, IIpPolicyStore ipPolicyStore)
    {
        _options = optionsAccessor.Value;
        _ipPolicyStore = ipPolicyStore;
    }

    [HttpGet]
    public string GetString(string content)
    {
        return content;
    }
    
    [HttpGet]
    public void AddGeneralRule()
    {
        _options.GeneralRules.Add(new RateLimitRule
        {
            Endpoint = "*",
            Limit = 2,
            Period = "30s"
        });

        if(_options.EndpointWhitelist==null)
        {
            _options.EndpointWhitelist=new List<string>();
        }

        _options.EndpointWhitelist.Add("get:/RateLimit/AddIpRule");
    }

    [HttpGet]
    public async Task AddIpRule()
    {
        var policy = await _ipPolicyStore.GetAsync(_options.IpPolicyPrefix, HttpContext.RequestAborted);

        if (policy == null)
        {
            await _ipPolicyStore.SeedAsync();

            policy = _ipPolicyStore.GetAsync(_options.IpPolicyPrefix).Result;
        }

        policy.IpRules.AddRange(new IpRateLimitPolicy
        {
            Ip = "::1",
            Rules = new List<RateLimitRule>(new RateLimitRule[] {
                new RateLimitRule {
                    Endpoint = "*:/RateLimit/GetString",
                    Limit = 5,
                    Period = "30s" },
					})
        },
           new IpRateLimitPolicy
           {
               Ip = "127.0.0.1",
               Rules = new List<RateLimitRule>(new RateLimitRule[] {
                   new RateLimitRule {
                       Endpoint = "*:/RateLimit/GetString",
                       Limit = 5,
                       Period = "30s" },
				})
        });

        await _ipPolicyStore.SetAsync(_options.IpPolicyPrefix, policy, cancellationToken: HttpContext.RequestAborted).ConfigureAwait(false);

    }        
}

参考文献：

$1$ https://github.com/stefanprodan/AspNetCoreRateLimit

$2$ https://github.com/stefanprodan/AspNetCoreRateLimit/wiki/IpRateLimitMiddleware