[C#] OWIN - WebApi Self-host

.NET   Web Api  

▌背景

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如何利用OWIN HttpListener server 建立一個Self-host Web Api的應用程式。

▌實作

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▋加入OWIN套件

請直接利用NUGET載入套件到專案中。
PS. 此篇文章使用的版本為5.2.3


▋加入設定檔

l   在專案中加入一個RouteConfig.cs 來設定Web Api的路由規則。

public class RouteConfig     {         /// <summary>         /// Configuration         /// </summary>         /// <param name="appBuilder"></param>         /// <remarks>注意方法名稱必須為Configuration</remarks>         public void Configuration(IAppBuilder appBuilder)         {             HttpConfiguration config = new HttpConfiguration();             config.Routes.MapHttpRoute(                 name: "DefaultApi",                 routeTemplate: "api/{controller}/{action}/{id}",                 defaults: new { id = RouteParameter.Optional }             );             appBuilder.UseWebApi(config);         }     }

▋加入ApiController

l   在專案中加入新的Controller，並繼承ApiController

public class TodoController:ApiController     {         [HttpGet]         public IEnumerable<Todo> Get()         {             var todo1 = new Todo() { MyName = "JB", MyAction = "Buy lunch", IsFinish = false };             var todo2 = new Todo() { MyName = "JB", MyAction = "Eat lunch", IsFinish = false };             var todo3 = new Todo() { MyName = "JB", MyAction = "Sleep", IsFinish = false };             List<Todo> todoList = new List<Todo>();             todoList.Add(todo1);             todoList.Add(todo2);             todoList.Add(todo3);             return todoList.AsEnumerable();         }         [HttpPost]         public void Print(IEnumerable<Todo> todoList)         {             Parallel.ForEach(todoList, todo => {                 Console.WriteLine(String.Format("{0} : {1} ({2})", todo.MyName, todo.MyAction, todo.IsFinish));             });         }     }

l   DTO 物件定義

public class Todo     {         public String MyName { get; set; }         public String MyAction { get; set; }         public bool IsFinish { get; set; }     }

▋主程式加入啟動服務的程式碼

static void Main(string[] args)         {             string baseAddress = "http://localhost:7531/"; //Assaign a port number here             // Start OWIN host             WebApp.Start<RouteConfig>(url: baseAddress);             #region Self-test : Create HttpCient and make a request             var client = new HttpClient();             var response = client.GetAsync(baseAddress + "api/todo/Get").Result;             Console.WriteLine(response);             Console.WriteLine(response.Content.ReadAsStringAsync().Result);             #endregion             Console.ReadLine();         }

▋測試

備註：

如果有跨來源資源共享的問題，仍必須從NUGET加入Enable CORS套件來避免。

並在註冊RouteConfig時加入以下程式碼：

public class RouteConfig     {          public void Configuration(IAppBuilder appBuilder)         {             //Skip …             //Enable CORS             config.EnableCors();         }     }

另在每個Http method上加上以下Attribute，設定的細節可參考此篇文章：
Enabling Cross-Origin Requests in ASP.NET Web API 2

[EnableCors(origins: "*", headers: "*", methods: "*")]

▌Reference

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Enabling Cross-Origin Requests in ASP.NET Web API 2 Use OWIN to Self-Host ASP.NET Web API 2