.NET 反向代理 YARP 通过编码方式配置域名转发

　　前面介绍了 YARP 通过配置文件的方式配置代理转发（传送门），而众所周知，微软的一贯作风就是能通过配置文件做的事情，通过编码的方式也能实现！YARP 也不例外，废话不多说，直接上代码！

　　首先，参照官方文档，我们先新建一个 InMemoryConfigProvider 类，并且继承 IProxyConfigProvider 接口，类里面还包含了一个  IProxyConfig 的类，别看漏了噢！

　　这里多嘴一下，下面的代码出现了 volatile 关键字，介绍一下它：volatile 是 C# 中用于控制同步的关键字，其意义是针对程序中一些敏感数据，不允许多线程同时访问，保证数据在任何访问时刻，最多有一个线程访问，以保证数据的完整性，volatile 是修饰变量的修饰符。

public class InMemoryConfigProvider : IProxyConfigProvider
{
    private volatile InMemoryConfig _config;

    public InMemoryConfigProvider(IReadOnlyList<RouteConfig> routes, IReadOnlyList<ClusterConfig> clusters)
    {
        _config = new InMemoryConfig(routes, clusters);
    }

    public IProxyConfig GetConfig() => _config;

    public void Update(IReadOnlyList<RouteConfig> routes, IReadOnlyList<ClusterConfig> clusters)
    {
        var oldConfig = _config;
        _config = new InMemoryConfig(routes, clusters);
        oldConfig.SignalChange();
    }

    private class InMemoryConfig : IProxyConfig
    {
        private readonly CancellationTokenSource _cts = new();

        public InMemoryConfig(IReadOnlyList<RouteConfig> routes, IReadOnlyList<ClusterConfig> clusters)
        {
            Routes = routes;
            Clusters = clusters;
            ChangeToken = new CancellationChangeToken(_cts.Token);
        }

        public IReadOnlyList<RouteConfig> Routes { get; }

        public IReadOnlyList<ClusterConfig> Clusters { get; }

        public IChangeToken ChangeToken { get; }

        internal void SignalChange()
        {
            _cts.Cancel();
        }
    }
}

　　然后添加一个扩展 InMemoryConfigProviderExtensions

public static class InMemoryConfigProviderExtensions
{
    public static IReverseProxyBuilder LoadFromMemory(this IReverseProxyBuilder builder, IReadOnlyList<RouteConfig> routes, IReadOnlyList<ClusterConfig> clusters)
    {
        builder.Services.AddSingleton<IProxyConfigProvider>(new InMemoryConfigProvider(routes, clusters));
        return builder;
    }
}

　　接下来就是写配置了，我个人还是喜欢在配置文件中写，但是有动态配置需求的话，又不想登录服务器编辑 appsetting 文件，通过编码的方式确实更为方便，将配置写进库或者其它存储方式里面，那将是随心所欲啊！上代码:

Program.cs

var routes = new[]
{
    new RouteConfig()
    {
        RouteId = "admin",
        ClusterId = "admin",
        Match = new RouteMatch
        {
            Hosts = new string[] {"test1.ysmc.net.cn" },
            Path = "{**catch-all}"
        }
    },

    new RouteConfig()
    {
        RouteId = "blazor",
        ClusterId = "blazor",
        Match = new RouteMatch
        {
            Hosts = new string[] {"test2.ysmc.net.cn" },
            Path = "{**catch-all}"
        }
    }
};

var clusters = new[]
{
    new ClusterConfig()
    {
        ClusterId = "admin",
        LoadBalancingPolicy = "RoundRobin",
        Destinations = new Dictionary<string, DestinationConfig>(StringComparer.OrdinalIgnoreCase)
        {
            { "admin", new DestinationConfig() { Address = "https://admin.blazor.zone" } }
        }
    },

    new ClusterConfig()
    {
        ClusterId = "blazor",
        LoadBalancingPolicy = "RoundRobin",
        Destinations = new Dictionary<string, DestinationConfig>(StringComparer.OrdinalIgnoreCase)
        {
            { "blazor", new DestinationConfig() { Address = "https://www.blazor.zone" } }
        }
    }
};

builder.Services.AddReverseProxy().LoadFromMemory(routes, clusters);

　　上面的配置代码，跟配置文件方式的节点和属性，都是对应的，照着写就是了

"ReverseProxy": {
  "Routes": {
    "admin": {
      "ClusterId": "admin",
      "Match": {
        "Hosts": [ "test1.ysmc.net.cn" ],
        "Path": "{**catch-all}"
      }
    },
    "blazor": {
      "ClusterId": "blazor",
      "Match": {
        "Hosts": [ "test2.ysmc.net.cn" ],
        "Path": "{**catch-all}"
      }
    }
  },
  "Clusters": {
    "admin": {
      "LoadBalancingPolicy": "RoundRobin",
      "Destinations": {
        "admin": {
          "Address": "https://admin.blazor.zone/"
        }
      }
    },
    "blazor": {
      "LoadBalancingPolicy": "RoundRobin",
      "Destinations": {
        "blazor": {
          "Address": "https://www.blazor.zone/"
        }
      }
    }
  }
}

　　最终效果还是依旧的完美，感谢大佬的观看，谢谢！

原文链接：https://www.cnblogs.com/ysmc/p/16724763.html