如果我们想对外发布RESTful API，可以基于ASP.NET来构建Restful APIs，但需要部署IIS吗？答案是不必。你可以把它托管到一个Windows Service。具体如何把WEB API自托管到Windows Service可以参考这一文章：Self-Host a Web API (HttpSelfHostServer) (C#). 基本上照着一步步做就行了。例子里是基于Windows Console Application，同样可以Self-Host到Windows Service.

问题在于如何把Controllers从Windows Service分离？可以使用autoFac，本文具体从这展开。

使用autoFac分离Controllers

autoFac是一个.NET IoC容器框架，这里我们用来分离Controllers，也就是说，我们把MVC的控制器Controllers放到独立的一个工程（Project），然后在Windows Service里面自托管（Self-Host）RESTful APIs。部署的时候只要部署windows service即可，不需要IIS，外部一样可以调用我们的RESTful APIs. 需要做的就是： 1. 引用autoFac 2. 注册Controllers 3. 设置DependencyResolver。好，我们新建一个project，类型是类库dll。添加引用：System.Web.Http；添加一个Controller：

using System;

using System.Net;

using System.Net.Http;

using System.Web.Http;

using Newtonsoft.Json;

namespace myCompany

{

    public class GroupController : ApiController, IGroupController

    {

        public HttpResponseMessage Update(HttpRequestMessage request)

        {

            Model model = null;

            var body = "";

            var valid = true;

            var result = new response { success = true, message = "" };

            HttpResponseMessage response;

            try

            {

                body = request.Content.ReadAsStringAsync().Result;

                /*

                 * According to the content type (text / json / xml), deserialize the request body

                 */

                model = Deserialize(body,

                    ModelUtility.GetMediaType(request.Content.Headers.ContentType.ToString()));

                if (model == null)

                    valid = false;

            }

            catch (Exception e)

            {

                valid = false;

            }

            if (!valid)

            {

                response = BuildFailureResponse(string.Format(

                    "Failure during parsing the request [{0}]", body));

            }

            else

            {

                 response = Request.CreateResponse<response>(HttpStatusCode.OK, result);

            }

            return response;

        }

        private static Model Deserialize(string data, MediaTypes type)

        {

            switch (type)

            {

                case MediaTypes.HTML:

                    break;

                case MediaTypes.JSON:

                    return JsonConvert.DeserializeObject<Model>(data);

                case MediaTypes.TEXT:

                    return new Model

                    {

                        name = ModelUtility.ParseText(data, "name"),

                        status = ModelUtility.ParseText(data, "status")

                    };

                case MediaTypes.XML:

                    return Utility.XmlSerilizer.Deserialize<Model>(data);

                case MediaTypes.UNKNOWN:

                    break;

                default:

                    break;

            }

            return null;

        }

        private HttpResponseMessage BuildFailureResponse(string message)

        {

            var result = new response { success = false, message = message };

            return Request.CreateResponse<response>(HttpStatusCode.BadRequest, result);

        }

    }

}

上面那个控制器可以处理RESTful API涉及group的请求。具体下面再谈。

回到我们已经创建Self-Host的Windows Service项目，里面添加引用Autofac.dll和Autofac.Integration.WebApi.dll。此外，可能还需要一些引用，我这里的列表如下：

然后在Windows Service项目里面添加一个类，内容如下：

using System.Reflection;

using System.Web.Http;

using Autofac;

using Autofac.Integration.WebApi;

namespace myCompany

{

    public class AutofacWebAPI

    {

        public static void Initialize(HttpConfiguration config)

        {

            config.DependencyResolver = new AutofacWebApiDependencyResolver(

                RegisterServices(new ContainerBuilder())

            );

        }

        private static IContainer RegisterServices(ContainerBuilder builder)

        {

            builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly()).PropertiesAutowired();

            builder.RegisterType<GroupController>().As<IGroupController>();

            return builder.Build();

        }

    }

}

主要就是用来aufoFac初始化和注册类型。然后在Windows service里面调用：

 public partial class Service : ServiceBase

 {

        private HttpSelfHostServer _server;

        private readonly HttpSelfHostConfiguration _config;

        public Service()

        {

            InitializeComponent();

            _config = new HttpSelfHostConfiguration(_serviceAddress);

            _config.Routes.MapHttpRoute("DefaultApi",

                "notifications/{controller}/{id}",

                new { id = RouteParameter.Optional });

        }

        protected override void OnStart(string[] args)

        {

	 /* Start self-host Web API */

                AutofacWebAPI.Initialize(GlobalConfiguration.Configuration);

                _server = new HttpSelfHostServer(_config);

                _server.OpenAsync();

       }

 }

就这么简单。此外，你还可以用其他的DependencyResolver方式，具体参考autoFac官方文档：https://code.google.com/p/autofac/wiki/WebApiIntegration

最后如何测试呢？

HTTP POST http://localhost:8080/notifications/group/update

post body (text/plain): name=abc&status=CANCELLED
post body (application/json): "{\"name\":\"abc\",\"status\":\"CANCELLED\"}";

post body (application/xml):

@"<myc:root xmlns:myc=""http://api.abc.com/Platform/1.0"">

<myc:name>abc</myc:name>

<myc:status>CANCELLED</myc:status>

</myc:root>";

看不懂的，可看代码。支持text/json/xml多种参数格式。RESTful API测试可以用Chrome插件：Postman REST Client。