If you are a C # developer, you can use what technology to create a Web document scanning applications cross-platform? The answer is ASP.NET Core and Dynamic Web TWAIN. In this article, I will share how to use these technologies from scratch to build a simple Web application.
True cross-platform document scanning solutions
Why Dynamic Web TWAIN scanning documents for development? This powerful feature SDK supports Windows, Linux and macOS.
installation
• ASP.NET Core
• Dynamic Web TWAIN
Construction of Hello World
How to create a new ASP.NET core project? You can read the tutorial provided by Microsoft .
mkdir aspnetcoreapp
cd aspnetcoreapp
dotnet new -t web
This is a file that contains so many beautiful Web project. Let's create an empty project using the command line:
dotnet new
This command only generates two files Program.cs and project.json. To run the application as a Web server:
- Modify 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 to add a dependency:
{
"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"
}
}
}
By dependency, we can run the Web server and load static resources such as HTML files, CSS files and images.
Creating 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();
}
}
}
The code will be loaded as the default index.html page.
Create a default static file folder wwwroot . The sample code to copy this folder ** from ** \ Samples. If you want to scan a document uploaded to a Web server, how to do? And save the file path mapping operation, as follows:
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);
}
}
});
}
}
}
Now run the Web project:
dotnet restore
dotnet run
Access localhost: 5000 to scan in a Web browser and upload documents.
Use MVC
If you want to take more action, we recommend using MVC. We look at how to change the code.
In project.json add dependencies:
{
"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
}
}
Adding MVC service and replaced with a route map Startup.cs in MVC:
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();
}
}
}
The default controller for the Home , the default action for the Index . Let wwwroot / index.html move to the Views / Home / the Index.cshtml . I do not want to add any code, but change the file suffix. Create a presentation index.cshtml of the Controllers / HomeController.cs :
using Microsoft.AspNetCore.Mvc;
namespace aspnetcoreapp.Controllers
{
public class HomeController : Controller
{
public IActionResult Index()
{
return View();
}
}
}
So far, we can run without problems and display the web page. The next step is to realize the function to upload files.
Open index.cshtml and change the operation page:
var strActionPage = CurrentPath + "upload";
To deal with the operation page, we must create the Controllers / 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();
}
}
}
}
}
that's it. Very simple!
Source Code
