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 routes, IReadOnlyList clusters)
{
builder.Services.AddSingleton(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(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