被动属性和嵌套容器

Question

最终解决方案

在@NightOwl888 的回答的帮助下，这是我为最终来到这里的任何人采用的最终方法：

1) 添加了全局过滤器提供程序：

public class GlobalFilterProvider : IFilterProvider
{
    public IEnumerable<Filter> GetFilters(ControllerContext controllerContext, ActionDescriptor actionDescriptor)
    {
        var nestedContainer = StructuremapMvc.StructureMapDependencyScope.CurrentNestedContainer;

        foreach (var filter in nestedContainer.GetAllInstances<IActionFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }

        foreach (var filter in nestedContainer.GetAllInstances<IAuthorizationFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }

        foreach (var filter in nestedContainer.GetAllInstances<IExceptionFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }

        foreach (var filter in nestedContainer.GetAllInstances<IResultFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }

        foreach (var filter in nestedContainer.GetAllInstances<IAuthenticationFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }
    }
}

2) 在 FilterProviders 集合中注册它：

public static void Application_Start()
{
    // other bootstrapping code...

    FilterProviders.Providers.Insert(0, new GlobalFilterProvider());
}

3) 使用 passive attributes 方法添加了自定义过滤器：

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false)]
public class SomeAttribute : Attribute
{
}

public class SomeFilter : IActionFilter
{
    private readonly ISomeDependency _dependency;

    public SomeFilter(ISomeDependency dependency)
    {
        _dependency = dependency;
    }

    public void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (!filterContext.ActionDescriptor.GetCustomAttributes(true).OfType<SomeAttribute>().Any())
            return;

        _dependency.DoWork();
    }

    public void OnActionExecuted(ActionExecutedContext filterContext)
    {
    }
}

4) 然后在 StructureMap 中连接所有内容（在此解决方案中，SomeAttribute 和 GlobalFilterProvider 类位于根文件夹内的同一 "Filters" 文件夹中）：

public class ActionFilterRegistry : Registry
{
    public ActionFilterRegistry()
    {
        Scan(s =>
        {
            // find assembly containing custom filters
            s.AssemblyContainingType<GlobalFilterProvider>();

            // limit it to the folder containing custom filters
            s.IncludeNamespaceContainingType<GlobalFilterProvider>();

            // exclude any of the Attribute classes that contain metadata but not the behavior
            s.Exclude(type => type.IsSubclassOf(typeof(Attribute)));

            // register our custom filters
            s.AddAllTypesOf<IActionFilter>();
        });
    }
}

原版Post

我目前在 ASP.NET MVC 5 应用程序中使用 StructureMap 的每个请求嵌套容器。我正在利用 structuremap.mvc5 nuget 包为我设置所有 DI 基础设施（依赖解析器、连接容器以及在 App_BeginRequest 和 App_EndRequest 上创建和处理嵌套容器） .我现在正处于需要在操作过滤器中执行一些 DI 以自动化某些功能的地步。经过大量研究，我尝试使用 Mark Seemann 的 passive attributes 方法在不需要 setter 注入的情况下这样做。

在构建属性和过滤器时一切似乎都很好，直到我在 App_Start 中将过滤器注册到全局过滤器集合。我有一个依赖项，我希望每个请求只创建一次，这样不仅动作过滤器，而且请求期间使用的其他非过滤器基础设施类都可以使用该依赖项的相同实例整个请求。如果嵌套容器正在解决依赖关系，它会默认这样做。但是，因为我必须在 App_Start 中注册新过滤器，所以我无权访问嵌套容器。

比如我的global.asax:

public class MvcApplication : System.Web.HttpApplication
{
    public static StructureMapDependencyScope StructureMapDependencyScope { get; set; }

    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        RouteConfig.RegisterRoutes(RouteTable.Routes);

        var container = IoC.Initialize(); // contains all DI registrations
        StructureMapDependencyScope = new StructureMapDependencyScope(container);
        DependencyResolver.SetResolver(StructureMapDependencyScope);

        // filter uses constructor injection, so I have to give it an instance in order to new it up, 
        // but nested container is not available
        GlobalFilters.Filters.Add(new SomeFilter(container.GetInstance<ISomeDependency>()));
    }

    protected void Application_BeginRequest()
    {
        StructureMapDependencyScope.CreateNestedContainer();
    }

    protected void Application_EndRequest()
    {
        HttpContextLifecycle.DisposeAndClearAll();
        StructureMapDependencyScope.DisposeNestedContainer();
    }

    protected void Application_End()
    {
        StructureMapDependencyScope.Dispose();
    }
}

有人知道怎么解决吗？我也通过这个 other SO question 遇到了 decoraptor 解决方案，但是在我的过滤器中使用抽象工厂只会创建一个新的依赖实例，而不是使用我想要的每个请求实例。

我想出的唯一其他解决方案是使用 setter 注入自定义过滤器提供程序，该提供程序使用在全局中创建的静态 StructureMapDependencyScope 实例，如下所示：

public class StructureMapFilterProvider : FilterAttributeFilterProvider
{
    public override IEnumerable<Filter> GetFilters(ControllerContext controllerContext, ActionDescriptor actionDescriptor)
    {
        var filters = base.GetFilters(controllerContext, actionDescriptor);

        foreach (var filter in filters)
        {
            MvcApplication.StructureMapDependencyScope.CurrentNestedContainer.BuildUp(filter.Instance);
        }

        return filters;
    }
}

虽然这似乎工作正常，但似乎有点脏。

Answer 1

您可以构建自定义过滤器提供程序（如）来控制过滤器的生命周期，而不是将它们注册到静态 GlobalFilters.Filters 集合中。

public class GlobalFilterProvider : IFilterProvider
{
    public IEnumerable<Filter> GetFilters(ControllerContext controllerContext, ActionDescriptor actionDescriptor)
    {
        var nestedContainer = StructuremapMvc.StructureMapDependencyScope.CurrentNestedContainer;

        foreach (var filter in nestedContainer.GetAllInstances<IActionFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }

        foreach (var filter in nestedContainer.GetAllInstances<IAuthorizationFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }

        foreach (var filter in nestedContainer.GetAllInstances<IExceptionFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }

        foreach (var filter in nestedContainer.GetAllInstances<IResultFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }

        foreach (var filter in nestedContainer.GetAllInstances<IAuthenticationFilter>())
        {
            yield return new Filter(filter, FilterScope.Global, order: null);
        }
    }
}

用法

请记住，MVC 已经包含很多过滤器类型。甚至 基本控制器类型的实现也被注册为全局过滤器 ，因为 Controller 实现了每种类型的过滤器。因此，在注册自定义全局过滤器类型时需要精确。

选项 1：使用基于约定的注册

// Register the filter provider with MVC.
FilterProviders.Providers.Insert(0, new GlobalFilterProvider());

然后在你的DI注册中

Scan(_ =>
{
    // Declare which assemblies to scan
    // In this case, I am assuming that all of your custom
    // filters are in the same assembly as the GlobalFilterProvider.
    // So, you need to adjust this if necessary.
    _.AssemblyContainingType<GlobalFilterProvider>();

    // Optional: Filter out specific MVC filter types
    _.Exclude(type => type.Name.EndsWith("Controller"));

    // Add all filter types.
    _.AddAllTypesOf<IActionFilter>();
    _.AddAllTypesOf<IAuthorizationFilter>();
    _.AddAllTypesOf<IExceptionFilter>();
    _.AddAllTypesOf<IResultFilter>();
    _.AddAllTypesOf<IAuthenticationFilter>(); // MVC 5 only
});

NOTE: You can control which filters MVC registers by changing the IFilterProvider instances that are registered.

所以，替代方案可能是这样的：

FilterProviders.Providers.Clear();

// Your custom filter provider
FilterProviders.Providers.Add(new GlobalFilterProvider());

// This provider registers any filters in GlobalFilters.Filters
FilterProviders.Providers.Add(new System.Web.Mvc.GlobalFilterCollection());

// This provider registers any FilterAttribute types automatically (such as ActionFilterAttribute)
FilterProviders.Providers.Insert(new System.Web.Mvc.FilterAttributeFilterCollection());

由于上面的代码没有注册System.Web.Mvc.ControllerInstanceFilterProvider，控制器本身不会注册为全局过滤器，所以你不需要过滤掉它们。相反，您可以简单地将所有控制器注册为全局过滤器。

// Optional: Filter out specific MVC filter types
// _.Exclude(type => type.Name.EndsWith("Controller"));

选项 2：个人注册

// Register the filter provider with MVC.
FilterProviders.Providers.Insert(0, new GlobalFilterProvider());

然后在你的DI注册中

For<IActionFilter>().Use<MyGlobalActionFilter>();
For<IActionFilter>().Use<MyOtherGlobalActionFilter>();

被动属性和嵌套容器

Passive Attributes and Nested Containers

c#

dependency-injection

asp.net-mvc-5

structuremap3

用法

选项 1：使用基于约定的注册

选项 2：个人注册