Question

目标是使用.AsWebApiAuthorizationFilterFor<ApiController>(c => c.GetType()将少数Attr转换为来自Autofac的DI过滤器

感觉像我接近了，但是可能做错了，发现了很多关于Peram注射器的帖子，但这不是我想要在这里做的。

当前失败的尝试

       builder.RegisterType<SomeFilter>()
            .AsWebApiAuthorizationFilterFor<ApiController>(c => c.GetType()
                .GetMethods()
                .Where(m => m.GetCustomAttributes<SomeAttribute>().Any())
            )
            .InstancePerRequest();

目标：为具有特定属性的所有api控制器和/或控制器方法添加此过滤器

从提供的答案中创建的解决方案：

创建自定义IAutofacAuthorizationFilter，并将ATTR中的当前过滤器逻辑移至该接口的auth方法。
为autofac builder.RegisterWebApiFilterProvider(config);添加了呼叫启用过滤器

注册我的过滤器

    builder.RegisterType<MyFilterFilter>()
        .AsWebApiAuthorizationFilterFor<BaseTypeApiController>()
        .InstancePerDependency();

添加对控制器或方法上原始属性的检查，如果两者都为空，则返回。

    var controllerAttribute = actionContext.ActionDescriptor.ControllerDescriptor.GetCustomAttributes<AttributeReplacedByFilterAttribute>().FirstOrDefault();
    var methodAttribute = actionContext.ActionDescriptor.GetCustomAttributes<AttributeReplacedByFilterAttribute>().FirstOrDefault();

到目前为止，这似乎可以解决问题，并满足了我的要求。

Answer 1

AsWebApiAuthorizationFilterFor的第二个参数是一个动作选择器，用于选择一种为其创建过滤器的方法。

要应用条件注册，可以使用OnlyIf：

// Conditionally register filter for all controller actions
services.GetContainerBuilder()
    .RegisterType<Filter>()
    .AsWebApiAuthorizationFilterFor<DummyController>()
    .OnlyIf(_ => typeof(DummyController).GetCustomAttributes<SomeAttribute>().Any());

// Conditionally register filter for selected controller action
services.GetContainerBuilder()
    .RegisterType<Filter>()
    // x => x.Get selects Get method defined by DummyController
    .AsWebApiAuthorizationFilterFor<DummyController>(x => x.Get())
    .OnlyIf(_ => 
     typeof(DummyController).GetMethod("Get").GetCustomAttributes<SomeAttribute>().Any());

您还可以构建自己的AsWebApiAuthorizationFilterForOnlyIf扩展名并执行以下操作：

if (typeof(DummyController).GetCustomAttributes<SomeAttribute>().Any())
{
    services.GetContainerBuilder()
        .RegisterType<Filter>()
        .AsWebApiAuthorizationFilterFor<DummyController>();
}

更新

如果喜欢使用scan-and-add-automatically方法，则可以使用表达式树为找到的每个控制器和方法动态调用AsWebApiAuthorizationFilterFor。您将在下面看到很多代码：

ContainerBuilder containerBuilder = ...
Type[] controllerTypes = ...

// Keep the type registration builder here, and use it for all As actions
var typeRegistrationBuilder = containerBuilder
    .RegisterType<Filter>()
    .InstancePerRequest();

// Scan controllers and methods and build registrations
foreach (Type controllerType in controllerTypes)
{
    // Which means ALL actions in the controller should have the filter registered
    if (controllerType.GetCustomAttributes<SomeAttribute>().Any())
    {
        // Because AsWebApiAuthorizationFilterFor doesn't take non-generic type parameter,
        // so we need to build delegate to invoke AsWebApiAuthorizationFilterFor<controllerType>.

        // Use expression tree.

        // This will build:
        // () => typeRegistrationBuilder.AsWebApiAuthorizationFilterFor<controllerType>()
        Expression.Lambda<Action>(
            Expression.Call(
                typeof(Autofac.Integration.WebApi.RegistrationExtensions),
                "AsWebApiAuthorizationFilterFor",
                new[] { controllerType },
                Expression.Constant(typeRegistrationBuilder))
        ).Compile()(); // Just compile and run this Action

        continue;
    }

    // Controller doesn't have the attribute
    // Scan action methods

    var methods = controllerType.GetMethods()
        .Where(mi => mi.GetCustomAttributes<SomeAttribute>().Any());
    foreach (MethodInfo method in methods)
    {
        // Now the method has the attribute
        // Again, use expression tree to build method call, but this time, with a selector

        // First, build method call expression parameters for each parameter on the method
        // Just need to pass default(T) in, because Autofac literally just need the method
        IEnumerable<Expression> parameters = method.GetParameters()
            .Select(p => p.ParameterType)
            .Select(Expression.Default);

        // Build method selector
        // This will build:
        // _ => _.SomeMethod(parameters)

        ParameterExpression controller = Expression.Parameter(controllerType, "_");
        LambdaExpression methodSelector = Expression.Lambda(
            typeof(Action<>).MakeGenericType(controllerType),
            Expression.Call(controller, method, parameters),
            controller);

        // This will build:
        // () => typeRegistrationBuilder.AsWebApiAuthorizationFilterFor<controllerType>(
        //     _ => _.SomeMethod(parameters));
        Expression.Lambda<Action>(
            Expression.Call(
                typeof(Autofac.Integration.WebApi.RegistrationExtensions),
                "AsWebApiAuthorizationFilterFor",
                new[] { controllerType },
                Expression.Constant(typeRegistrationBuilder),
                methodSelector)
        ).Compile()(); // Just compile and run this Action
    }
}

Answer 2

从提供的答案中创建的解决方案：

创建自定义IAutofacAuthorizationFilter，并将ATTR中的当前过滤器逻辑移至该接口的auth方法。
为autofac builder.RegisterWebApiFilterProvider(config);添加了呼叫启用过滤器

注册我的过滤器

    builder.RegisterType<MyFilterFilter>()
        .AsWebApiAuthorizationFilterFor<BaseTypeApiController>()
        .InstancePerDependency();

添加对控制器或方法上原始属性的检查，如果两者都为null，则返回。向过滤器方法添加了检查：OnAuthorizationAsync(HttpActionContext actionContext, CancellationToken cancellationToken)

    var controllerAttribute = actionContext.ActionDescriptor.ControllerDescriptor.GetCustomAttributes<AttributeReplacedByFilterAttribute>().FirstOrDefault();
    var methodAttribute = actionContext.ActionDescriptor.GetCustomAttributes<AttributeReplacedByFilterAttribute>().FirstOrDefault();

到目前为止，这似乎可以解决问题，并满足了我的要求。

注意：您可以使用相同的方法将过滤器应用于所有控制器方法，然后检查属性。对于我的用例，我有一个需要影响的控制器的基类。注册以将所有过滤器注册更改为.AsWebApiAuthorizationFilterFor<ApiController>()

Autofac ApiController筛选器具有属性的方法

2 个答案: