如何将 IHttpContextAccessor 注入 Autofac TenantIdentificationStrategy

Question

我正在将我的多租户应用程序从 Webapi 迁移到 aspnet 核心。在 webapi 版本中，我使用 TenantIdentificationStrategy 来根据 HttpContext.

上的请求路径识别租户

转向 aspnet 核心，我能够成功连接 autofac。我无法弄清楚如何连接租户策略。我尝试在 ConfigureServices 中注入 IHttpContextAccessor 作为

services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();

我的策略是这样的

public class AssetClassIdentificationStrategy: ITenantIdentificationStrategy {
    private readonly IHttpContextAccessor _accessor;
    public AssetClassIdentificationStrategy(IHttpContextAccessor httpContextAccessor)
    {
        _accessor = httpContextAccessor;
    }
    public bool TryIdentifyTenant(out object tenantId) {
        tenantId = null;
        var context = _accessor.HttpContext;
        if (context != null && context.Request != null )){
            var matchRegex = new Regex(@"\/[\d,\.,\w]*\/(\w*)\/.*");
            var match = matchRegex.Match(context.Request.Path.ToString());
            if (match.Success) {
                tenantId = match.Groups[1].Value.ToLower();
            }
        }
        return tenantId != null;
    }
}

我看到的是 HttpContextAccessor 被正确注入，其中 HttpContext 始终为空。因此，none 的多租户服务正在得到解决。

四处寻找示例，但找不到适合问题的内容。 Autofacv3 中曾经有一个 RequestParameterTenantIdentificationStrategy 不再支持。感谢对此的任何帮助。

编辑修复了代码问题并按要求添加 Startup.cs。

public class Startup
{
    public Startup(IHostingEnvironment env) {
        var builder = new ConfigurationBuilder()
            .SetBasePath(env.ContentRootPath)
            .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);

        Configuration = builder.Build();
    }

    public IConfigurationRoot Configuration { get; }

    public IServiceProvider ConfigureServices(IServiceCollection services)
    {
        services.Configure<CacheConfig>(Configuration.GetSection("Caching"),false);
        services.AddMvc();
        services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
        services.AddTransient<ITenantIdentificationStrategy,AssetClassIdentificationStrategy>();

        var builder = new ContainerBuilder();
        builder.Populate(services);
        builder.RegisterType<TenantInfo>().WithProperty("TenantName", "unknown").As<ITenantInfo>();

        var container = builder.Build();

        ITenantIdentificationStrategy tenantIdentificationStrategy;
        bool isMultiTenant = container.TryResolve(out tenantIdentificationStrategy);

        var mtc = new MultitenantContainer(tenantIdentificationStrategy, container);
        mtc.ConfigureTenant("pesonalLoans", b => {
            b.RegisterType<TenantInfo>().WithProperty("TenantName","pesonalLoans") .As<ITenantInfo>();
        });
        mtc.ConfigureTenant("retirement", b => {
            b.RegisterType<TenantInfo>().WithProperty("TenantName", "retirement").As<ITenantInfo>();
        });

        return mtc.Resolve<IServiceProvider>();

    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
    {
        LoggingConfig.Register(Configuration, loggerFactory);
        app.UseMvc();
    }
}


public class ValuesController : Controller {
    private ITenantInfo _tenant;
    public ValuesController(ITenantInfo tenant) {
        _tenant = tenant;
    }

    [HttpGet]
    public string Get()
    {
        return  _tenant.TenantName;
    }
}


public interface ITenantInfo {
    string TenantName { get; set; }
}
public class TenantInfo: ITenantInfo
{
    public string TenantName { get; set; }
}

编辑 3 project.json

{
  "dependencies": {
    "Microsoft.NETCore.App": {
      "version": "1.0.0-rc2-3002702",
      "type": "platform"
    },
    "Microsoft.AspNetCore.Mvc": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.0-rc2-final",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0-rc2-final",
    "Microsoft.Extensions.Configuration.FileExtensions": "1.0.0-rc2-final",
    "Microsoft.Extensions.Configuration.Json": "1.0.0-rc2-final",
    "Microsoft.Extensions.Logging": "1.0.0-rc2-final",
    "Microsoft.Extensions.Logging.Console": "1.0.0-rc2-final",
    "Microsoft.Extensions.Logging.Debug": "1.0.0-rc2-final",
    "Autofac": "4.0.0-rc2-240",
    "Autofac.Multitenant": "4.0.0-beta8-219",
    "System.IdentityModel.Tokens.Jwt": "5.0.0-rc2-305061149",
    "Autofac.Extensions.DependencyInjection": "4.0.0-rc2-240",
    "System.Reflection": "4.1.0-rc2-24027",
    "System.Reflection.Primitives": "4.0.1-rc2-24027",
    "System.Reflection.Extensions": "4.0.1-rc2-24027",
    "System.Reflection.TypeExtensions": "4.1.0-rc2-24027",
    "System.Reflection.Emit": "4.0.1-rc2-24027",
    "System.Reflection.Context": "4.0.1-rc2-24027",
    "System.Reflection.DispatchProxy": "4.0.1-rc2-24027",
    "System.Reflection.Emit.ILGeneration": "4.0.1-rc2-24027",
    "Microsoft.AspNetCore.Diagnostics": "1.0.0-rc2-final",
    "Microsoft.AspNet.Mvc.Formatters.Xml": "6.0.0-rc1-final",
    "Microsoft.AspNet.Mvc.Formatters.Json": "6.0.0-rc1-final",
  },

  "tools": {
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": {
      "version": "1.0.0-preview1-final",
      "imports": "portable-net45+win8+dnxcore50"
    }
  },

  "frameworks": {
    "netcoreapp1.0": {
      "imports": [
        "dotnet5.6",
        "dnxcore50",
        "portable-net45+win8"
      ]
    }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "runtimeOptions": {
    "gcServer": true
  },

  "scripts": {
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }
}

Answer 1

评论太长了。

首先，您的 class 被命名为 SampleIdentificationStrategy，但您的构造函数引用了 AssetClassIdentificationStrategy。从这个问题开始，项目甚至不应该编译。

接下来（因为您还没有提供启动文件）确保通过在 ConfigureServices 方法中调用以下代码来填充 AutoFac 中的注册服务。

builder.Populate(services);
builder.Update(container);

请注意此方法必须运行在您已将所有服务注册到 IServiceCollection

接下来确保您没有混用框架版本。 RC2 RC1、beta-x 等之间存在很大差异。这已在 GitHub 问题日志中注明 here and here。

除此之外，我们还需要查看您的 startup.cs 文件（特别是 ConfigureServices 方法的摘录，您的 project.json 文件（特别是 frameworks 和 dependency 节点).

Answer 2

目前没有办法将东西注入到租户识别策略中，因为该策略本身不通过 DI 管道。

IHttpContextAccessor 通常仅由 HttpContextAccessor 支持，无论如何这是一个单例，并通过从 async/thread 本地上下文获取信息来执行操作。您可以在启动时直接使用其中之一来更新您的策略：

var strat = new MyStrategy(new HttpContextAccessor());

请注意，在最初提出问题时，多租户与 ASP.NET 核心 IServiceProvider 系统交互的方式存在问题，也就是说，它没有。

从那时起，我们发布了 4.0.0-rc3-309 for the Autofac.Extensions.DependencyInjection package 解决了这个问题。

变化是您需要将ConfigureServices更新为return new AutofacServiceProvider(mtc);，不再执行return mtc.Resolve<IServiceProvider>();。

如何将 IHttpContextAccessor 注入 Autofac TenantIdentificationStrategy

How to inject IHttpContextAccessor into Autofac TenantIdentificationStrategy

c#

autofac

multi-tenant

asp.net-core

asp.net-core-1.0