Document Scanning from ASP.net Web Application

Question

I have a ASP.Net C# 4.0 Web Application

I need to Add a scanning feature for my users. This is what I want to achieve On my web application

1. user clicks on a button
2. opens a window with preview of document in Scanning device attached to the client system
3. User confirms the Scan
4. this will save the Scanned document in jpg/pdf format on the server
5. then do the OCR on document

Can any one suggest a way to achieve this.

I read about this https://www.leadtools.com/sdk/engine/imaging not sure how much this can work. Can any one suggest a best way to get this done.

Thanks

update

tried leadtools from https://www.leadtools.com/support/forum/posts/m28036-Re--Scan-and-Upload-v16--NET-with-Caspol-exe-deployment as LEAD Support suggested but it is missing references not sure where and how to get those references

Answer 1

HaBo, This is LEAD support. Since you mentioned our LEADTOOLS toolkit, the answer to your question is yes. Our toolkit can be used to implement either of the 2 approaches mentioned by tgolisch.

For the click-once approach, you simply use our Windows Forms controls that contain Twain support and package your application for ClickOnce deployment. This is done, for example, in this demo project: LEADTOOLS ClickOnce Demos

For the custom control approach, see the example code projects on our forums that perform Scan and Upload

Answer 2

Solution is here:

1. In ASP.Net/Core Project you send message to call winform project:

           var start = function () {
           var i = 0;
           var wsImpl = window.WebSocket || window.MozWebSocket;
           window.ws = new wsImpl('ws://localhost:8181/');
           ws.onmessage = function (e) {
               $('#submit').hide();
               $('#scanBtn').hide();
               $('.loader').show();
               if (typeof e.data === "string") {
                   //IF Received Data is String
               }
               else if (e.data instanceof ArrayBuffer) {
                   //IF Received Data is ArrayBuffer
               }
               else if (e.data instanceof Blob) {
                   i++;
                   var f = e.data;
                   f.name = "File" + i;
                   storedFiles.push(f);
                   formdata.append(f.name, f);
                   var reader = new FileReader();
                   reader.onload = function (e) {
                       var html = "<div class=\"col-sm-2 text-center\" 
                   style=\"border: 1px solid black; margin-left: 2px;\"><img 
                   height=\"200px\" width=\"200px\" src=\"" + e.target.result + "\" 
                   data-file='" + f.name + "' class='selFile' title='Click to 
                   remove'><br/>" + i + "</div>";
                       selDiv.append(html);
                       $('#submit').show();
                       $('#scanBtn').show();
                       $('.loader').hide();
                   }
                   reader.readAsDataURL(f);
               }
           };
           ws.onopen = function () {
               //Do whatever u want when connected succesfully
           };
           ws.onclose = function () {
               $('.dalert').modal('show');
           };
       }
       window.onload = start;
       function scanImage() {
           ws.send("1100");
       };
   

https://javascript.info/websocket

2. In Winforms Project you scan document and send graphic data back to Asp.Net/Core project:

   public partial class Form1 : Form { ImageCodecInfo _tiffCodecInfo; TwainSession _twain; bool _stopScan; bool _loadingCaps; List allSockets; WebSocketServer server; public Form1() { InitializeComponent();

    if (NTwain.PlatformInfo.Current.IsApp64Bit)
   {
       Text = Text + " (64bit)";
   }
   else
   {
       Text = Text + " (32bit)";
   }
   foreach (var enc in ImageCodecInfo.GetImageEncoders())
   {
       if (enc.MimeType == "image/tiff") { _tiffCodecInfo = enc; break; }
   }
   
   this.WindowState = FormWindowState.Minimized;
   this.ShowInTaskbar = false;
   
   allSockets = new List<IWebSocketConnection>();
   server = new WebSocketServer("ws://0.0.0.0:8181");
   server.Start(socket =>
   {
       socket.OnOpen = () =>
       {
           Console.WriteLine("Open!");
           allSockets.Add(socket);
       };
       socket.OnClose = () =>
       {
           Console.WriteLine("Close!");
           allSockets.Remove(socket);
       };
       socket.OnMessage = message =>
       {
           if (message == "1100")
           {
               this.Invoke(new Action(()=> {
                   this.WindowState = FormWindowState.Normal;
               }));
           }
       };
   });
   

   }

Link to project.

https://github.com/mgriit/ScanAppForWeb

You can remake this project, as you want.

Answer 3

Web browsers don't have permissions to use system devices like this(major security issue). There are 2 common ways of getting around this:

1. Make a custom control to run in your browser (flash, silverlight, java applet).
2. Make a "click-once deployment app" that a user launches from your page.

Both approaches would send the data back to your server via web services or WCF, etc.