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TenantIdentificationStrategy根据请求路径使用了已识别的租户HttpContext.

转到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.我试着注入IHttpContextAccessor在ConfigureServices如

services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>(); 

我的策略看起来像这样

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;
    }
}

我所看到的是HttpContextAccessor正确注入,其中HttpContext始终为null.因此,没有任何多租户服务得到解决.

查看样本,但找不到符合问题的任何内容.曾经有一个RequestParameterTenantIdentificationStrategy不再支持的Autofacv3.感谢任何帮助.

编辑已 修复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

当前没有将事物注入到租户识别策略中的方法，因为该策略本身不会通过DI管道。

IHttpContextAccessor通常只支持HttpContextAccessor单例，并通过从异步/线程本地上下文中获取信息来执行操作。在启动时，您可以直接使用以下策略之一重新制定策略：

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

请注意，最初提出该问题时，多租户与ASP.NET Core IServiceProvider系统交互的方式存在问题，也就是说，事实并非如此。

从那时起，我们发布4.0.0-rc3-309了Autofac.Extensions.DependencyInjection可解决该问题的软件包。

更改是您需要更新ConfigureServices到return new AutofacServiceProvider(mtc);不再执行的操作return mtc.Resolve<IServiceProvider>();。