OWIN 中 K Commands 與 OwinHost.exe 相等嗎？

• OwinHost.exe: While some will want to write a custom PRocess to run Katana Web applications, many would prefer to simply launch a pre-built executable that can start a server and run their application. For this scenario, the Katana component suite includes OwinHost.exe. When run from within a project’s root directory, this executable will start a server (it uses the HttpListener server by default) and use conventions to find and run the user’s startup class. For more granular control, the executable provides a number of additional command line parameters.
• K Commands: Whenever you want to run your app in command line using K* commands, you will use k run. The K command is your entry point to the runtime. To run an application you can use K run to build you can use K build, and all other commands that are about taking your application and running it.

K Commands 是 APS.NET 5 引出的，根據說明知道它是加載與啟動 OWIN 組件的一個命令，那 OwinHost.exe 是什么？它其實是之前 OWIN 的實現 Katana 項目中的一個東西，這個東西是什么？看一下源碼結構：

摘自 Program.cs 中的一段源代碼：

using System;using System.Collections.Generic;using System.Diagnostics.CodeAnalysis;using System.Globalization;using System.IO;using System.Linq;using System.Reflection;using Microsoft.Owin.Hosting;using Microsoft.Owin.Hosting.Services;using Microsoft.Owin.Hosting.Starter;using Microsoft.Owin.Hosting.Utilities;using OwinHost.Options;namespace OwinHost{    public static class Program    {        public static void RunServer(StartOptions options)        {            if (options == null)            {                return;            }            string boot;            if (!options.Settings.TryGetValue("boot", out boot)                || string.IsNullOrWhiteSpace(boot))            {                options.Settings["boot"] = "Domain";            }            ResolveAssembliesFromDirectory(                Path.Combine(Directory.GetCurrentDirectory(), "bin"));            WriteLine("Starting with " + GetDisplayUrl(options));            IServiceProvider services = ServicesFactory.Create();            var starter = services.GetService<IHostingStarter>();            IDisposable server = starter.Start(options);            WriteLine("Started successfully");            WriteLine("Press Enter to exit");            Console.ReadLine();            WriteLine("Terminating.");            server.Dispose();        }    }}

可以看到，它其實和 Microsoft.aspNet.Hosting/Program.cs 中的配置代碼很相似，但不相同，Microsoft.AspNet.Hosting 是 OWIN Host 的所有概念實現，而 OwinHost 只是一個控制臺啟動程序，用來加載所有的 OWIN 組件，但它不包含任何的實現，比如 Host 中的 Builder、Server、Startup 等一些操作，再看下面一張圖就明白了：

對，沒錯，OwinHost 依賴于 Microsoft.Owin.Hosting，OwinHost 中所有的 Host 操作都在 Microsoft.Owin.Hosting 中進行完成了，說白了，OwinHost 沒多少東西，就是一個開啟命令，和 Microsoft.AspNet.Hosting 完全不是一個概念問題，那 OwinHost 和 K Commands 相等嗎？其實也不相等，只是很類似，但這個類似點只是體現在加載 OWIN 組件的時候，OwinHost 的工作就是干這個的，并且只能干這個，而 K Commands 卻不僅僅如此，它還包含了其他的一些命令管理，比如“gen”、“ef”等。

其他相關資料：

• What is the difference between using Owinhost.exe to run an OWIN web service or a Console App
• Visual Studio 2013 Custom Web Servers and OwinHost.exe