使用Autofac在ASP.NET Web API上实现依赖注入

【原文】Dependency Injection in ASP.NET Web API using Autofac

摘要

在ASP.NET Web API里使用Autofac

通过NuGet安装Autofac.WebApi。（当然要先安装Autofac.dll)。

PM > Install-Package Autofac.WebApi

引用如下命名空间。

using Autofac;
using Autofac.Integration.WebApi;

再按照如下代码配置Autofac。

 public static class Bootstrapper
    {
        public static void Run()
        {
            SetAutofacWebAPI();
        }
        private static void SetAutofacWebAPI()
        {
            var configuration = GlobalConfiguration.Configuration;
            var builder = new ContainerBuilder();
            // Configure the container  
            builder.ConfigureWebApi(configuration);
            // Register API controllers using assembly scanning. 
            builder.RegisterApiControllers(Assembly.GetExecutingAssembly());
            builder.RegisterType<DefaultCommandBus>().As<ICommandBus>()
                .InstancePerApiRequest();
            builder.RegisterType<UnitOfWork>().As<IUnitOfWork>()
                .InstancePerApiRequest();
            builder.RegisterType<DatabaseFactory>().As<IDatabaseFactory>()
                .InstancePerApiRequest();
            builder.RegisterAssemblyTypes(typeof(CategoryRepository)
                .Assembly).Where(t => t.Name.EndsWith("Repository"))
                .AsImplementedInterfaces().InstancePerApiRequest();
            var services = Assembly.Load("EFMVC.Domain");
            builder.RegisterAssemblyTypes(services)
                .AsClosedTypesOf(typeof(ICommandHandler<>))
                .InstancePerApiRequest();
            builder.RegisterAssemblyTypes(services)
                .AsClosedTypesOf(typeof(IValidationHandler<>))
                .InstancePerApiRequest();
            var container = builder.Build();
            // Set the WebApi dependency resolver.  
            var resolver = new AutofacWebApiDependencyResolver(container);
            configuration.ServiceResolver.SetResolver(resolver);
        }
    }

在Application_Start里调用Bootstrapper.Run()。

        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            RegisterGlobalFilters(GlobalFilters.Filters);
            RegisterRoutes(RouteTable.Routes);
            BundleTable.Bundles.RegisterTemplateBundles();
            //Call Autofac DI configurations   
            Bootstrapper.Run();
        }

Autofac.Mvc4

Autofac ASP.NET MVC integration已经升级到MVC4。 NuGet pacakgeAutofac.Mvc4。它提供了ASP.NET MVC4里的依赖注入（不包括Web API）。Autofac.Mvc3与Autofac.Mvc4没有什么语法上的不同。

源码

http://efmvc.codeplex.com/ 

一个样例Web程序，用来展示ASP.NET MVC、EF Code First以及架构实践。

 

相关资源：

Autofac官网 http://code.google.com/p/autofac/

Autofac ASP.NET MVC3 Ingetation http://code.google.com/p/autofac/wiki/Mvc3Integration