ASP.NET Core应用：文件扫描上传

微软的东西越来越棒了，各种开源和跨平台工具相继推出。.NET Core终于让.NET开始像Java一样，可以在任意平台上运行代码。最近学习了下微软的教程，结合跨平台的Dynamic Web TWAIN，分享下我的第一个ASP.NET Core "Hello World"。

安装

• ASP.NET Core
• Dynamic Web TWAIN

Hello World

如何初始化一个ASP.NET Core的工程？根据微软的教程：

mkdir aspnetcoreappcd aspnetcoreappdotnet new -t web

创建的工程包含了很多的文件，已经比较复杂了。要搞明白发生了什么，还是一步一步创建文件比较好。所以只需要用命令：

dotnet new

这样会创建一个命令行工程，包含两个文件Program.cs和project.json。我需要的是web server，所以修改下这两个文件。

Program.cs:

using System.IO;using aspnetcoreapp;using Microsoft.AspNetCore.Hosting; namespace ConsoleApplication{    public class Program    {        public static void Main(string[] args)        {            var host = new WebHostBuilder()                .UseKestrel()                .UseContentRoot(Directory.GetCurrentDirectory())                .UseStartup<Startup>()                .Build();             host.Run();        }    }}

project.json:

{  "version": "1.0.0-*",  "buildOptions": {    "debugType": "portable",    "emitEntryPoint": true  },  "dependencies": {},  "frameworks": {    "netcoreapp1.0": {      "dependencies": {        "Microsoft.NETCore.App": {          "type": "platform",          "version": "1.0.1"        },        "Microsoft.AspNetCore.Server.Kestrel": "1.0.1",        "Microsoft.AspNetCore.StaticFiles": "1.0.0"      },      "imports": "dnxcore50"    }  }}

这里做的事情就是添加了web server Kestrel,以及通过当前路径加载静态文静。还需要创建一个Startup.cs：

using System.IO;using Microsoft.AspNetCore.Builder;using Microsoft.AspNetCore.Hosting; namespace aspnetcoreapp{    public class Startup    {        public void Configure(IApplicationBuilder app)        {            // app.UseDefaultFiles();            // app.UseStaticFiles();            app.UseFileServer();        }    }}

UseFileServer等同与UseDefaultFiles+UseStaticFiles。默认加载wwwroot目录下的静态文件，并把index.html当作首页。当然你可以通过代码去修改路径。如果现在部署静态html文件，已经可以访问了。

为了让server端做一点事情，做一个文件上传功能。首先需要映射一下路径，比如上传的url是www.xxx.com/upload。打开index.html做一下修改：

var strActionPage = CurrentPath + "upload";

一旦满足条件就可以执行操作：

using System.IO;using Microsoft.AspNetCore.Builder;using Microsoft.AspNetCore.Hosting; namespace aspnetcoreapp{    public class Startup    {        public void Configure(IApplicationBuilder app)        {            // app.UseDefaultFiles();            // app.UseStaticFiles();            app.UseFileServer();             app.Map("/upload", UploadFile);        }         private static void UploadFile(IApplicationBuilder app)        {            app.Run(async context =>            {                var files = context.Request.Form.Files;                var uploads = Path.Combine(Directory.GetCurrentDirectory(), "uploads");                if (!Directory.Exists(uploads)) {                    Directory.CreateDirectory(uploads);                }                 foreach (var file in files)                {                    var filename = file.FileName;                    using (var fileStream = new FileStream(Path.Combine(uploads, filename), FileMode.Create))                    {                        await file.CopyToAsync(fileStream);                    }                }            });        }    }}

现在可以运行下程序：

dotnet restoredotnet run

浏览器中打开localhost:5000看到的效果：

MVC

现在用MVC来改造下上面的代码。首先在project.json中添加新的依赖：

{  "version": "1.0.0-*",  "buildOptions": {    "debugType": "portable",    "emitEntryPoint": true  },  "dependencies": {},  "frameworks": {    "netcoreapp1.0": {      "dependencies": {        "Microsoft.NETCore.App": {          "type": "platform",          "version": "1.0.1"        },        "Microsoft.AspNetCore.Mvc": "1.0.1",        "Microsoft.AspNetCore.Server.Kestrel": "1.0.1",        "Microsoft.AspNetCore.StaticFiles": "1.0.0"      },      "imports": "dnxcore50"    }  },   "buildOptions": {    "emitEntryPoint": true,    "preserveCompilationContext": true  }}

在Startup.cs中添加MVC服务：

using Microsoft.AspNetCore.Builder;using Microsoft.Extensions.DependencyInjection; namespace aspnetcoreapp{    public class Startup    {        public void Configure(IApplicationBuilder app)        {            app.UseStaticFiles();             app.UseMvc(routes =>            {                routes.MapRoute(                    name: "default",                    template: "{controller=Home}/{action=Index}/{id?}");            });        }         // This method gets called by the runtime. Use this method to add services to the container.        public void ConfigureServices(IServiceCollection services)        {            services.AddMvc();        }    }}

MVC中使用了路径模版。默认情况下需要一个HomeController.cs:

using Microsoft.AspNetCore.Mvc; namespace aspnetcoreapp.Controllers{    public class HomeController : Controller    {        public IActionResult Index()        {            return View();        }    }}

这个文件放在Controller目录下。对应的还有一个Index.cshtml文件，放在Views/Home目录下。把之前的那个index.html改一下名就可以了。

因为上传的URL是www.xxx.com/upload，相对的也要创建一个Controller/UploadController.cs：

using Microsoft.AspNetCore.Mvc;using System.IO; namespace aspnetcoreapp.Controllers{    public class UploadController : Controller    {        [HttpPost]        public void Index()        {            var files = Request.Form.Files;            var uploads = Path.Combine(Directory.GetCurrentDirectory(), "uploads");            if (!Directory.Exists(uploads))            {                Directory.CreateDirectory(uploads);            }             foreach (var file in files)            {                var filename = file.FileName;                using (var fileStream = new FileStream(Path.Combine(uploads, filename), FileMode.Create))                {                    file.CopyTo(fileStream);                    fileStream.Flush();                }            }        }    }}

这样就完成了。

源码

https://github.com/dynamsoft-dwt/ASP.NET-Core