1，OWIN的介绍

  OWIN 的全称是 "Open Web Interface for .NET"， OWIN 在 .NET Web 服务器和 .NET Web 应用之间定义了一套标准的接口， 其目的是为了实现服务器与应用之间的解耦，使得便携式 .NET Web 应用以及跨平台的愿望成为现实， 标准的 OWIN 应用可以在任何 OWIN 兼容的服务器上运行， 不再依赖于Windows和IIS 。

2，添加NutGet

添加Microsoft.AspNet.WebApi.Owin 和 Microsoft.AspNet.WebApi.Owin Self Host包（Self Host 用于开启OWIN Host，设置监听接受Http请求）

 3，添加Startup类

   Startup是OWIN约定的，用于对OWIN做相关配置的，代码如下：

<code>using Owin;

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net.Http.Headers;

using System.Text;

using System.Threading.Tasks;

using System.Web.Http;

using System.Web.Http.Cors;

namespace WebAPIServer

{

/// <summary>

/// Startup是OWIN约定的，用于对OWIN做相关配置

/// </summary>

public class Startup

{

public void Configuration(IAppBuilder appBuilder)

{

try

{

HttpConfiguration config = new HttpConfiguration();

config.Formatters.JsonFormatter.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));

config.EnableCors(new EnableCorsAttribute("*", "*", "*"));

//启用路由特性

config.MapHttpAttributeRoutes();

config.Routes.MapHttpRoute(

name: "DefaultApi",

routeTemplate: "api/{controller}/{id}",

defaults: new { id = RouteParameter.Optional },

constraints: new { id = @"\d*" }//新增一个约束，指定id只能是数字，不能是其他

);

//再自定义一个路由,第一个路由匹配失败再匹配这个

config.Routes.MapHttpRoute(

name: "ActionApi",

routeTemplate: "api/{controller}/{action}/{id}",

defaults: new { id = RouteParameter.Optional }

);

appBuilder.UseWebApi(config);

}

catch (Exception ex)

{

throw ex;

}

}

}

}

4，新建Controllers文件夹，添加FileControllers类

    按照 Web API 项目的约定，在项目中添加一个名称为 Controllers 的文件夹，然后新建 一个FileController类，设置其基类为 System.Web.Http.ApiController ，作为示例，其内容与 Visual Studio 自带的 Web API Controller 模板一致，包含4种请求方式（GET/POST/PUT/DELETE），用于演示，重写GET方法（直接返回请求参数）和POST方法（接受实体类参数直接返回），FileController代码如下：

using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Net;

using System.Net.Http;

using System.Net.Http.Headers;

using System.Threading.Tasks;

using System.Web;

using System.Web.Http;

using WebAPIServer.Services;

namespace WebAPIServer.Controllers

{

/// <summary>

/// 文件类控制器

/// </summary>

public class FileController : ApiController

{

private string UploadFolderPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "UploadFolder");

private MediaServer _mediaServer = new MediaServer();

/// <summary>

/// 上传文件

/// </summary>

/// <returns></returns>

[HttpPost]

public async Task<IHttpActionResult> UploadFolder()

{

if (!Request.Content.IsMimeMultipartContent("form-data"))

{

return StatusCode(HttpStatusCode.UnsupportedMediaType);

}

var provider = new MultipartMemoryStreamProvider();

await Request.Content.ReadAsMultipartAsync(provider);

await _mediaServer.UploadFolder(provider, UploadFolderPath);

// 创建文件夹（如果尚未存在）

return Ok();

}

[HttpGet]

public async Task<HttpResponseMessage> DownloadFile(string fileName)

{

// 获取文件路径

string filePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "~/UploadFolder/" + fileName);

// 检查文件是否存在

if (!File.Exists(filePath))

{

return Request.CreateErrorResponse(HttpStatusCode.NotFound, "The specified file does not exist.");

}

// 创建 HTTP 响应消息

HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);

// 设置响应内容

using (FileStream fileStream = File.OpenRead(filePath))

{

response.Content = new StreamContent(fileStream);

// 设置响应头

response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");

response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")

{

FileName = fileName

};

await response.Content.LoadIntoBufferAsync();

}

return response;

}

}

using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Net.Http;

using System.Threading.Tasks;

using System.Web;

namespace WebAPIServer.Services

{

public class MediaServer

{

/// <summary>

/// 上传文件

/// </summary>

/// <param name="provider"></param>code>

/// <param name="_uploadFolder"></param>code>

/// <returns></returns>

public async Task UploadFolder(MultipartMemoryStreamProvider provider, string _uploadFolder)

{

// 创建文件夹（如果尚未存在）

Directory.CreateDirectory(_uploadFolder);

foreach (var content in provider.Contents)

{

var disposition = content.Headers.ContentDisposition;

var fileName = disposition.FileName.Trim('"');

fileName = Path.GetFileName(fileName);

var fileData = await content.ReadAsByteArrayAsync();

// 将文件保存到本地文件夹中

var filePath = Path.Combine(_uploadFolder, fileName);

using (var fileStream = new FileStream(filePath, FileMode.Create))

{

await fileStream.WriteAsync(fileData, 0, fileData.Length);

}

}

}

}

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net.Http;

using System.Text;

using System.Threading.Tasks;

using System.Web.Http;

namespace WebAPIServer.Controllers

{

/// <summary>

/// 验证管理控制器

/// </summary>

public class AuthorizationController : ApiController

{

// GET api/<controller>

public string Get()

{

return "ok";

}

// GET api/<controller>/5

public string Get(int id)

{

return string.Format("owin {0} by:linezero", id);

}

/// <summary>

/// 获取授权码

/// </summary>

/// <param name="info"></param>code>

/// <returns></returns>

[Route("api/Authorization"), HttpPost] // 自定义路由

public async Task<HttpResponseMessage> GetAuthorizationCode([FromBody] AuthorizationInfo info)

{

await Task.Run(() =>

{

//进行计算并将相应值保存至服务器

WebAPIOWINServer.AuthorizationInfoRequest?.Invoke(this, info);

});

HttpResponseMessage response = new HttpResponseMessage(System.Net.HttpStatusCode.OK);

response.Content = new StringContent($"感谢您的支持，我们将以邮件的形式将授权码发送给您的Email:{info.Email}，请注意查收。", Encoding.UTF8);

return response;

}

// PUT api/<controller>/5

public string Put([FromBody] string value)

{

return "Success";

}

// DELETE api/<controller>/5

public string Delete([FromBody] string value)

{

return "Success";

}

}

public class AuthorizationInfo

{

public string Id { get; set; }

public string CPUSerialNumber { get; set; }

public string BIOSSerialNumber { get; set; }

public string Email { get; set; }

public DateTime CreateDate { get; set; }

}

}

5，添加WebApi服务类，代码如下：