OWIN是Open Web Server Interface for .NET的首字母缩写，他的定义如下：
OWIN在.NET Web Servers与Web Application之间定义了一套标准接口，OWIN的目标是用于解耦Web Server和Web Application。基于此标准，鼓励开发者开发简单、灵活的模块，从而推进.NET Web Development开源生态系统的发展。
为什么我们需要OWIN
过去，IIS作为.NET开发者来说是最常用的Web Server（没有之一），源于微软产品的紧耦合关系，我们不得不将Website、Web Application、Web API等部署在IIS上，事实上在2010年前并没有什么不妥，但随着近些年来Web的发展，特别是移动互联网飞速发展，IIS作为Web Server已经暴露出他的不足了。主要体现在两个方面，ASP.NET (System.Web)紧耦合IIS，IIS紧耦合OS，这就意味着，我们的Web Framework必须部署在微软的操作系统上，难以跨平台。
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OWIN是什么？在本文里面就不进行赘述，网上有很多介绍OWIN的信息以及优缺点的博文，这里可以给几个链接大家进行自行参考：
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下面我们重点介绍我在搭建OWIN自宿主平台的过程，对于我是学习的过程，对于想要接触他的大家来说，也是一种帮助。
很多人搭建的OWIN+WebApi项目都是写在一个项目中的，我个人为了代码的隔离，将控制器层写在了另外一个项目中，这样有助于后期大型框架的形成。
下面是搭建步骤：
1、首先新建一个控制台应用程序和一个.NETFramework类库项目，控制台引用类库项目。
项目结构如下图所示：
OWIN.WebApi WebApi层
OWIN.WebApi.Sv WebApi服务层，将要作为启动项！
2、控制台项目使用NuGet引用需要的类库：
OWIN
Microsoft.Owin.Hosting
Microsoft.Owin.Host.HttpListener
Microsoct.AspNet.WebApi.Owin
这里需要手动从WebApi项目里面找到System.Web.Web,System.Net.Http等Web类库进行引用。
OWIN.WebApi.Srv层的引用情况（我这里有跨域配置，不需要的请忽略）
在OWIN.WebApi层，我们需要同样引用Web的类库，我们才可以在WebApi项目控制器层继承自ApiController
OWIN.WebApi层的引用情况（我这里有跨域配置，不需要的请忽略）
3、因为WebApi层要分开类库项目写，所以这里比一般的OWIN要多一些配置，在我项目的OWIN.WebApi层的config目录下，我新建了一个Global.cs类，里面的代码是对控制器的解析，代码展示如下：
using System.Web.Http;
using System.Web.Http.Dispatcher;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http.Controllers;
namespace OWIN.WebApi.config
{
public class WebApiApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
//ignore the xml return it`s setting let json return only
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
GlobalConfiguration.Configuration.Formatters.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);
GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpControllerSelector),
new WebApiControllerSelector(GlobalConfiguration.Configuration));
}
}
/// <summary>
/// the WebApiControllerSelector
/// author:qixiao
/// time:2017-1-31 19:24:32
/// </summary>
public class WebApiControllerSelector : DefaultHttpControllerSelector
{
private const string NamespaceRouteVariableName = "Namespace";
private readonly HttpConfiguration _configuration;
private readonly Lazy<ConcurrentDictionary<string, Type>> _apiControllerCache;
public WebApiControllerSelector(HttpConfiguration configuration)
: base(configuration)
{
_configuration = configuration;
_apiControllerCache = new Lazy<ConcurrentDictionary<string, Type>>(
new Func<ConcurrentDictionary<string, Type>>(InitializeApiControllerCache));
}
private ConcurrentDictionary<string, Type> InitializeApiControllerCache()
{
IAssembliesResolver assembliesResolver = this._configuration.Services.GetAssembliesResolver();
var types = this._configuration.Services.GetHttpControllerTypeResolver()
.GetControllerTypes(assembliesResolver).ToDictionary(t => t.FullName, t => t);
return new ConcurrentDictionary<string, Type>(types);
}
public IEnumerable<string> GetControllerFullName(HttpRequestMessage request, string controllerName)
{
object namespaceName;
var data = request.GetRouteData();
IEnumerable<string> keys = _apiControllerCache.Value.ToDictionary<KeyValuePair<string, Type>, string, Type>(t => t.Key,
t => t.Value, StringComparer.CurrentCultureIgnoreCase).Keys.ToList();
if (!data.Values.TryGetValue(NamespaceRouteVariableName, out namespaceName))
{
return from k in keys
where k.EndsWith(string.Format(".{0}{1}", controllerName,
DefaultHttpControllerSelector.ControllerSuffix), StringComparison.CurrentCultureIgnoreCase)
select k;
}
string[] namespaces = (string[])namespaceName;
return from n in namespaces
join k in keys on string.Format("{0}.{1}{2}", n, controllerName,
DefaultHttpControllerSelector.ControllerSuffix).ToLower() equals k.ToLower()
select k;
}
public override HttpControllerDescriptor SelectController(HttpRequestMessage request)
{
Type type;
if (request == null)
{
throw new ArgumentNullException("request");
}
string controllerName = this.GetControllerName(request);
if (string.IsNullOrEmpty(controllerName))
{
throw new HttpResponseException(request.CreateErrorResponse(HttpStatusCode.NotFound,
string.Format("No route providing a controller name was found to match request URI '{0}'", new object[] { request.RequestUri })));
}
IEnumerable<string> fullNames = GetControllerFullName(request, controllerName);
)
{
throw new HttpResponseException(request.CreateErrorResponse(HttpStatusCode.NotFound,
string.Format("No route providing a controller name was found to match request URI '{0}'", new object[] { request.RequestUri })));
}
if (this._apiControllerCache.Value.TryGetValue(fullNames.First(), out type))
{
return new HttpControllerDescriptor(_configuration, controllerName, type);
}
throw new HttpResponseException(request.CreateErrorResponse(HttpStatusCode.NotFound,
string.Format("No route providing a controller name was found to match request URI '{0}'", new object[] { request.RequestUri })));
}
}
}4、在OWIN.WebApi.Srv层里面新建AppStart.cs类，并且写如下代码：
using Microsoft.Owin.Hosting;
using System;
using Owin;
using System.Web.Http;
using System.Web.Http.Dispatcher;
using QX_Frame.App.WebApi.Extends;
using System.Web.Http.Cors;
namespace OWIN.WebApi.Srv
{
class AppStart
{
static void Main(string[] args)
{
//string baseAddress = "http://localhost:3999/"; //localhost visit
string baseAddress = "http://+:3999/"; //all internet environment visit
try
{
WebApp.Start<StartUp>(url: baseAddress);
Console.WriteLine("BaseIpAddress is " + baseAddress);
Console.WriteLine("\nApplication Started !");
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
for (;;)
{
Console.ReadLine();
}
}
}
//the start up configuration
class StartUp
{
public void Configuration(IAppBuilder appBuilder)
{
HttpConfiguration config = new HttpConfiguration();
// Web API configuration and services
//跨域配置 //need reference from nuget
config.EnableCors(new EnableCorsAttribute("*", "*", "*"));
//enabing attribute routing
config.MapHttpAttributeRoutes();
// Web API Convention-based routing.
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional },
namespaces: new string[] { "OWIN.WebApi" }
);
config.Services.Replace(typeof(IHttpControllerSelector), new OWIN.WebApi.config.WebApiControllerSelector(config));
//if config the global filter input there need not write the attributes
//config.Filters.Add(new App.Web.Filters.ExceptionAttribute_DG());
//new ClassRegisters(); //register ioc menbers
appBuilder.UseWebApi(config);
}
}
}里面对地址进行了配置，当然可以根据需求自行配置，显示信息也进行了适当的展示，需要说明的一点是，我这里进行了跨域的配置，没有配置或者是不需要的请注释掉并忽略！
这里需要注意的是第53行，这里引用的是刚才的OWIN.WebApi层的Global.cs里面的类，请对照上述两段代码进行查找。
这行是关键，有了这行，程序才可以扫描到WebApi层的Controller。好了，我们进行Controller的书写。
5、在OWIN.WebApi层进行控制器类的编写，这里随意，我只在这里列出我的例子。
using QX_Frame.App.WebApi;
using QX_Frame.Helper_DG;
using System.Web.Http;
namespace OWIN.WebApi
{
/*
* author:qixiao
* time:2017-2-27 10:32:57
**/
public class Test1Controller:ApiController
{
//access http://localhost:3999/api/Test1 get method
public IHttpActionResult GetTest()
{
//throw new Exception_DG("login id , pwd", "argumets can not be null", 11111, 2222);
return Json(new { IsSuccess = true, Msg = "this is get method" });
}
//access http://localhost:3999/api/Test1 post method
public IHttpActionResult PostTest(dynamic queryData)
{
return Json(new { IsSuccess = true, Msg = "this is post method",Data=queryData });
}
//access http://localhost:3999/api/Test1 put method
public IHttpActionResult PutTest()
{
return Json(new { IsSuccess = true, Msg = "this is put method" });
}
//access http://localhost:3999/api/Test1 delete method
public IHttpActionResult DeleteTest()
{
return Json(new { IsSuccess = true, Msg = "this is delete method" });
}
}
}这里我是用的是RESTFull风格的WebApi控制器接口。
然后我们可以进行试运行：
服务启动成功！
测试通过，我们可以尽情地探索后续开发步骤！