c# ACME client (补充)

上一篇 c# ACME client 漏了一部分内容，今天补上

除了之前介绍的在 asp.net core 使用方式，还可以单独在代码中使用client

简化用法

如果已经集成好完全的自动证书申请验证，就可以使用已经封装好的代码进行简单使用

举例在asp.net core提供一个api 可以根据参数申请证书

starup

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllers();

builder.Services.AddAcmeChallengeCore(config: c =>

{

    c.HttpClientConfig = new VKProxy.Config.HttpClientConfig()

    {

        DangerousAcceptAnyServerCertificate = true

    };

});

var app = builder.Build();

if (app.Environment.IsDevelopment())

{

    app.MapOpenApi();

}

app.UseAuthorization();

app.MapControllers();

app.Run();

api

using Microsoft.AspNetCore.Mvc;

using VKProxy.ACME.AspNetCore;

using VKProxy.Core.Extensions;

namespace WithApi.Controllers;

[ApiController]

[Route("[controller]")]

public class CertController : ControllerBase

{

    private readonly IAcmeStateIniter initer;

    public CertController(IAcmeStateIniter initer)

    {

        this.initer = initer;

    }

    [HttpGet]

    public async Task<string> Get([FromQuery] string domain)

    {

        // 证书配置

        var o = new AcmeChallengeOptions()

        {

            AllowedChallengeTypes = VKProxy.ACME.AspNetCore.ChallengeType.Http01,

            Server = new Uri("https://127.0.0.1:14000/dir"),

            DomainNames = new[] { domain },

            AdditionalIssuers = new[] { """

                        -----BEGIN CERTIFICATE-----

                        MIIDGzCCAgOgAwIBAgIIUPFry5qBu34wDQYJKoZIhvcNAQELBQAwIDEeMBwGA1UE

                        AxMVUGViYmxlIFJvb3QgQ0EgMjFjNjY3MCAXDTI1MDcyMjAxMTA0OVoYDzIwNTUw

                        NzIyMDExMDQ5WjAgMR4wHAYDVQQDExVQZWJibGUgUm9vdCBDQSAyMWM2NjcwggEi

                        MA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCxNKa4y93OFYaSx8bcbuWsHHnW

                        mpfsobK5Elf7GE02mi/cDrMP+wR1l53BuucrW04OyoewkBsJNZoxEy1DkCjxv4+g

                        Q+HgGCR5R14ex17ZdFxpcl42H8QnRB3IqVBlJiz0JyGZwiaOamOkUTVEYTGDeuxu

                        PglpvboGeatsWQe0MJJfBN8OxLVUmi6Y/enbzlIdv3tvgQujfPNiS8MLDMBuIiMs

                        ixhu8YAzUqvVKZoQVK7GwbD9WrVBKub8w86StKFmU14aSXahidt8IENdpLO2OT3J

                        y1nt25QDsAmtS1/wGnTDPeefLGsM7kGYNesQkSW0w8Um4p9KLWKnKyOvzPZrAgMB

                        AAGjVzBVMA4GA1UdDwEB/wQEAwIChDATBgNVHSUEDDAKBggrBgEFBQcDATAPBgNV

                        HRMBAf8EBTADAQH/MB0GA1UdDgQWBBRoXcwo6c5J8jMweiHKPw4OlcWIQzANBgkq

                        hkiG9w0BAQsFAAOCAQEAad9XT4sN1KserYtCxBKmoPhPAHInHYgG/Z2gd6KqdsK9

                        biIgEbKo84tClLqA6XCN/yN1bMQL2ZMbWBF8oHv/A5o0atpTpd+Ho+punHYRIpqv

                        akUX21Zsu6NdAuH7g7m9t9h/lc6tgiqaAf2HwpC3NrXmUlPRqLay7/t+BFQU6dBa

                        E+qzmL7lHZQf1UArfb+QDYH2XsFCk9Pjv0xdP+PGwf8HqHhfPLctvus5JL+LXp0X

                        68eWKQCs1CrL8cUMwcELlW/mR1lKnJL1WgM1Bns9ZF1ha6egG539ruzQjItF6MHB

                        xAEt55nXfs+mjV1p7qrcmR8jIdByR9C36T21r+8pKA==

                        -----END CERTIFICATE-----

                        """

            }

        };

        // 申请全新account

        o.NewAccount(new string[] { "mailto:test11@xxx.com" });

        // 执行全套流程

        var cert = await initer.CreateCertificateAsync(o);

        return cert.ExportPem();

    }

}

默认情况下三种验证方式：

http

如在 asp.net core 中使用，默认已经添加了 app.Map("/.well-known/acme-challenge" 路由处理，如要申请公网上权威认证的证书，请将 /.well-known/acme-challenge 路由暴露在公网让acme服务器可以访问

其次由于默认实现没有持久化和分布式处理验证信息，重启和多实例都会有问题，如有需求可以替换IHttpChallengeResponseStore实现以达到效果

public interface IHttpChallengeResponseStore

{

    Task AddChallengeResponseAsync(string token, string keyAuth, CancellationToken cancellationToken);

    Task<string> GetChallengeResponse(string token, CancellationToken cancellationToken);

    Task RemoveChallengeResponseAsync(string token, CancellationToken cancellationToken);

}

dns

由于不同服务商有各自的api，所以默认没有实现，该功能其实无效，如需使用，请实现 IDnsChallengeStore

public interface IDnsChallengeStore

{

    Task AddTxtRecordAsync(string acmeDomain, string dnsTxt, CancellationToken cancellationToken);

    Task RemoveTxtRecordAsync(string acmeDomain, string dnsTxt, CancellationToken cancellationToken);

}

tls

个人并不推荐使用tls验证方式，其由于验证自签证书和正式证书都会在 tls 层，运行时不停机重新申请对于tls管理还是有些挑战的

如想尝试可以实现ITlsAlpnChallengeStore （默认在 asp.net core 的实现并不能支持过滤验证自签证书只用于acme服务器请求）

public interface ITlsAlpnChallengeStore

{

    Task AddChallengeAsync(string domainName, X509Certificate2 cert, CancellationToken cancellationToken);

    Task RemoveChallengeAsync(string domainName, X509Certificate2 cert, CancellationToken cancellationToken);

}

底层 client

如需直接使用原始 acme 协议client，可参考如下

starup

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllers();

builder.Services.AddACME(c =>

{

    c.HttpClientConfig = new VKProxy.Config.HttpClientConfig()

    {

        DangerousAcceptAnyServerCertificate = true

    };

});

use

var context = services.BuildServiceProvider().GetRequiredService<IAcmeContext>();

await context.InitAsync(new Uri("https://127.0.0.1:14000/dir"), cancellationToken);

var account = await context.NewAccountAsync(new string[] { "mailto:xxx@xxx.com" }, true, KeyAlgorithm.RS256.NewKey());

var order = await context.NewOrderAsync(new string[] { "test.com" });

var aus = order.GetAuthorizationsAsync().ToBlockingEnumerable().ToArray();

var a = aus.First();

var b = await a.HttpAsync();

var c = await b.ValidateAsync();

Key privateKey = KeyAlgorithm.RS256.NewKey();

var csrInfo = new CsrInfo

{

    CommonName = "test.com",

};

order = await context.FinalizeAsync(csr, key, cancellationToken);

var acmeCert = await order.DownloadAsync();

var pfxBuilder = acmeCert.ToPfx(privateKey);

if (!string.IsNullOrWhiteSpace(Args.AdditionalIssuer) && File.Exists(Args.AdditionalIssuer))

{

    pfxBuilder.AddIssuer(File.ReadAllBytes(Args.AdditionalIssuer));

}

var pfx = pfxBuilder.Build("HTTPS Cert - " + Args.Domain, string.Empty);

var r = X509CertificateLoader.LoadPkcs12(pfx, string.Empty, X509KeyStorageFlags.Exportable);

ui

在 VKProxy管理站点的 ui sni 里面添加了简单的 http 验证方式的acme证书界面配置如下图

（当然使用前提得是暴露 xxx域名/.well-known/acme-challenge 接口到公网，这样公网acme 才能验证）

专职ACME管理程序

其实对更多人来说，ACME都是低频率使用，只是现在免费证书大多90天，所以才期望有个工具帮自己干活

现成的很多，比如

acme.sh 脚本工具，稍显复杂
certimate 目前只支持 dns 验证，不过dns服务商/通知/证书部署都支持非常全面

所以珠玉在前，大家可以直接尽情使用

至于用c#再做一个，多半没有啥人关注，不信，和大家打个赌：评论留言说期望有个c#版的超过 30 条，就搞一个（一条评论都没有，信不信，哈哈哈）

VKProxy 是使用c#开发的基于 Kestrel 实现 L4/L7的代理（感兴趣的同学烦请点个github小赞赞呢）