使用 Autofac 将 SignalR IHubContext 注入服务层

Question

在运行 Framework 4.72 而不是 .NET Core 的应用中，我尝试将 SignalR IHubContext 注入 Web API 2.x 服务。我的解决方案分为三个项目，网络、服务、数据。 SignalR 集线器位于 Web 层中。我有在服务层中运行的后台代码，完成后我需要它通过集线器发送消息。这个后台任务不是由控制器发起的。

我的 Global.asax 非常标准：

 protected void Application_Start()
{
    GlobalConfiguration.Configure(WebApiConfig.Register);

    // Set JSON serializer to use camelCase
    var json = GlobalConfiguration.Configuration.Formatters.JsonFormatter;
    json.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();

    DIConfig.Setup();

    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);

    var logConfigFilePath = Server.MapPath("~/log4net.config");
    log4net.Config.XmlConfigurator.ConfigureAndWatch(new System.IO.FileInfo(logConfigFilePath));
}

我的 DIConfig 包含：

internal static void Setup()
{
    var config = System.Web.Http.GlobalConfiguration.Configuration;
    var builder = new ContainerBuilder();

    builder.Register(c => new ShopAPDbContext()).AsImplementedInterfaces().InstancePerBackgroundJob().InstancePerLifetimeScope();
    builder.RegisterType<ShopAPRepository>().As<IShopAPRepository>().InstancePerBackgroundJob().InstancePerLifetimeScope();
    builder.RegisterType<ShopAPService>().As<IShopAPService>().InstancePerBackgroundJob().InstancePerLifetimeScope();

    builder.AddAutoMapper(typeof(InvoiceMappingProfile).Assembly);
    builder.RegisterApiControllers(Assembly.GetExecutingAssembly());
    var container = builder.Build();

    DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
    config.DependencyResolver = new AutofacWebApiDependencyResolver(container);

    Hangfire.GlobalConfiguration.Configuration.UseAutofacActivator(container);
}

还有我的 Startup.cs：

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        var container = DependencyConfiguration.Configure(app);
        SignalRConfiguration.Configure(app, container);
        HangFireDashboardConfig.Configure(app);
    }
}

public static class DependencyConfiguration
{
    public static IContainer Configure(IAppBuilder app)
    {
        var builder = new ContainerBuilder();
        builder.RegisterHubs(typeof(SignalRConfiguration).Assembly);
        var container = builder.Build();
        app.UseAutofacMiddleware(container);
        return container;
    }
}

public static class SignalRConfiguration
{
    public static void Configure(IAppBuilder app, IContainer container)
    {
        HubConfiguration config = new HubConfiguration();
        config.Resolver = new AutofacDependencyResolver(container);

        app.Map("/messages", map =>
        {
            map.UseCors(CorsOptions.AllowAll);
            var hubConfiguration = new HubConfiguration
            {
                EnableDetailedErrors = true,
                EnableJavaScriptProxies = false
            };
            map.RunSignalR(hubConfiguration);
        });
    }
}

我的服务层的构造函数如下所示：

public ShopAPService()
{
    _shopAPRepository = new ShopAPRepository();
    _mapper = new Mapper((IConfigurationProvider)typeof(InvoiceMappingProfile).Assembly);
    _hubContext = null;  // what here?
}

public ShopAPService(IShopAPRepository shopAPRepository, IMapper mapper, IHubContext hubContext)
{
    _shopAPRepository = shopAPRepository;
    _mapper = mapper;
    _hubContext = hubContext;
}

我知道我需要将 IHubContext 的一个实例传递给服务，但到目前为止我还没有成功。据我所知，第一个构造函数是从控制器以外的任何其他对象调用服务时使用的？

---

第一次修订

好的，我知道所有东西都应该放在一个容器中。根据反馈并查看这些链接，我创建了一个容器并将其传递。这是我修改后的启动：

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        //var config = System.Web.Http.GlobalConfiguration.Configuration;
        var container = GetDependencyContainer();

        RegisterWebApi(app, container);
        RegisterSignalR(app, container);

        GlobalHost.DependencyResolver = new AutofacDependencyResolver(container);
        HubConfiguration config = new HubConfiguration();
        config.Resolver = new AutofacDependencyResolver(container);

        //config.DependencyResolver = new AutofacWebApiDependencyResolver(container);
        Hangfire.GlobalConfiguration.Configuration.UseAutofacActivator(container);

        HangFireDashboardConfig.Configure(app);
    }

    private IContainer GetDependencyContainer()
    {
        return AutofacConfig.RegisterModules();
    }

    private void RegisterWebApi(IAppBuilder app, IContainer container)
    {
        var configuration = new HttpConfiguration
        {
            DependencyResolver = new AutofacWebApiDependencyResolver(container)
        };

        WebApiConfig.Register(configuration);

        app.UseAutofacMiddleware(container);
        app.UseAutofacWebApi(configuration);
        app.UseWebApi(configuration);
    }

    private void RegisterSignalR(IAppBuilder app, IContainer container)
    {
        var configuration = new HubConfiguration
        {
            Resolver = new AutofacDependencyResolver(container)
        };

        app.MapSignalR(configuration);
    }
}

我的 AutofacConfig 构建容器并完成大部分注册：

internal class AutofacConfig
{
    public static IContainer RegisterModules()
    {
        var builder = new ContainerBuilder();

        builder.Register(c => new ShopAPDbContext()).AsImplementedInterfaces().InstancePerBackgroundJob().InstancePerLifetimeScope();
        builder.RegisterType<ShopAPRepository>().As<IShopAPRepository>().InstancePerBackgroundJob().InstancePerLifetimeScope();
        builder.RegisterType<ShopAPService>().As<IShopAPService>().InstancePerBackgroundJob().InstancePerLifetimeScope();

        builder.RegisterAutoMapper(typeof(InvoiceMappingProfile).Assembly);
        builder.RegisterApiControllers(Assembly.GetExecutingAssembly());

        // Register Autofac resolver into container to be set into HubConfiguration later
        builder.RegisterType<AutofacDependencyResolver>().As<IDependencyResolver>().SingleInstance();

        // Register ConnectionManager as IConnectionManager so that you can get hub context via IConnectionManager injected to your service
        builder.RegisterType<ConnectionManager>().As<IConnectionManager>().SingleInstance();

        builder.RegisterHubs(Assembly.GetExecutingAssembly());

        var container = builder.Build();

        return container;
    }
}

但是，我仍然无法在我的服务中获得对 Hub 的引用（它与 API 在一个单独的项目中，但在同一个解决方案中。

我的 Service 方法是从 HangFire 调用的，并且没有对 Hub 的引用。如何在无参数构造函数中引用它？

public partial class ShopAPService : IShopAPService
{
    private static readonly ILog _log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

    readonly IShopAPRepository _shopAPRepository;
    readonly IMapper _mapper;
    private IHubContext _hubContext;

    public ShopAPService()
    {
        _shopAPRepository = new ShopAPRepository();
        _mapper = new Mapper((IConfigurationProvider)typeof(InvoiceMappingProfile).Assembly);
        _hubContext = connectionManager.GetHubContext<MessageHub>();
    }

    public ShopAPService(IShopAPRepository shopAPRepository, IMapper mapper, IHubContext hubContext)
    {
        _shopAPRepository = shopAPRepository;
        _mapper = mapper;
        _hubContext = hubContext;
    }
}

Answer 1

您无法直接解析IHubContext。但是您可以解决此接口的通用实现。更多细节描述here和here。

我只是创建了OWIN (Stratup.cs) 的非常简单的实现。 我已经安装了Autofac.SignalR nugget 包并使用方法RegisterHubs 进行注册和方法MapSignalR 进行映射。它是标准方法，并且可以很好地解决类型化的 Hub 实现。

但如果您希望更正确地解析上下文，则需要再添加两个注册：AutofacDependencyResolver 和 ConnectionManager（更多信息可用here）。

请查看完整示例：

using Autofac;
using Autofac.Integration.SignalR;
using Autofac.Integration.WebApi;
using Microsoft.AspNet.SignalR;
using Microsoft.Owin;
using Owin;
using System.Reflection;
using System.Web.Http;

[assembly: OwinStartup(typeof(Startup))]
namespace Sample
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            var container = GetDependencyContainer();

            RegisterWebApi(app, container);
            RegisterSignalR(app, container);
        }

        private IContainer GetDependencyContainer()
        {
            var builder = new ContainerBuilder();

            AutofacConfig.RegisterModules(builder);
            builder.RegisterApiControllers(Assembly.GetExecutingAssembly());
            builder.RegisterHubs(Assembly.GetExecutingAssembly());

            // Register Autofac resolver into container to be set into HubConfiguration later
            builder.RegisterType<AutofacDependencyResolver>().As<IDependencyResolver>().SingleInstance();
            // Register ConnectionManager as IConnectionManager so that you can get hub context via IConnectionManager injected to your service
            builder.RegisterType<ConnectionManager>().As<IConnectionManager>().SingleInstance();

            var container = builder.Build();

            return container;
        }

        private void RegisterWebApi(IAppBuilder app, IContainer container)
        {
            var configuration = new HttpConfiguration
            {
                DependencyResolver = new AutofacWebApiDependencyResolver(container)
            };

            WebApiConfig.Register(configuration);

            app.UseAutofacMiddleware(container);
            app.UseAutofacWebApi(configuration);
            app.UseWebApi(configuration);
        }

        private void RegisterSignalR(IAppBuilder app, IContainer container)
        {
            var configuration = new HubConfiguration
            {
                Resolver = new AutofacDependencyResolver(container)
            };

            app.MapSignalR(configuration);
        }
    }
}

我的 Hub 既标准又简单：

public class MaintenanceHub : Hub
{
    public MaintenanceHub(IMaintenanceLogProvider maintenanceLogProvider)
    {
        maintenanceLogProvider.TaskProgressStatusEvent += (s, e) => GetTaskLogStatus(e);
    }

    public void GetTaskLogStatus(LongTaskProgressStatus taskProgressStatus)
    {
        Clients.All.getTaskLogStatus(taskProgressStatus);
    }
}

注册后，您可以使用 Hub 注入上下文。类似的东西（有 2 个选项，你只能使用你想要的一个）：

public AccountController(IConnectionManager connectionManager, MaintenanceHub maintenanceHub)
{
    var context = connectionManager.GetHubContext<MaintenanceHub>();
    var hub = maintenanceHub;
}