ASP.NET WEB API的服务托管(Self-HOST)

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：

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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：

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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：

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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。