Browser hangs when clicking cancel on File Transfer

gkoulouris · **Joined:** Mon Mar 28, 2011 7:19 am **Posts:** 4

If a user cancels a File Transfer (HttpUpload*) the web browser hangs and becomes unresponsive. If the user waits long enough, they get the error message in the alert box (our code is below)

Is there anything we can do to catch the cancel event and handle it gracefully?

Code:

function UploadImage() {
   var CurrentPathName = unescape(location.pathname); // get current PathName in plain ASCII   
   var CurrentPath = CurrentPathName.substring(0, CurrentPathName.lastIndexOf("/") + 1);

   WebTwain3.IfSSL = window.location.protocol == "https:";
   if (WebTwain3.IfSSL) {
      WebTwain3.HTTPPort = 443;
   }
   
   var docFormat = GetSettings("Format", "PDF"); // default is pdf
   var docFileName = "ScannedDocument." + docFormat.toLowerCase();

   CopyToBufferForUpload();

   switch (docFormat) {
      case "JPG":
         WebTwain3.HTTPUploadThroughPost(strHostIP, 0, actionPage, docFileName); 
         break;
      case "TIFF":
         WebTwain3.HTTPUploadAllThroughPostAsMultiPageTIFF(strHostIP, actionPage, docFileName); 
         break;
      case "PDF":
      default:
         WebTwain3.HTTPUploadAllThroughPostAsPDF(strHostIP, actionPage, docFileName); 
         break;
   }

   CopyToBufferForReturn();

   if ((WebTwain3.HTTPPostResponseString).length > 0) {
      
      var queryString = WebTwain3.HTTPPostResponseString + "&nodeId=" + GetQueryString("nodeId", "0") + "&ImagesLeft=" + (WebTwain3.HowManyImagesInBuffer - LastPage.innerHTML);

      queryString += "&isQuickFinder=" + IsQuickFinder();
      var quickFinderMultipleIndex = GetQueryString("QuickFinderMultipleIndex", "0");

      queryString += "&QuickFinderMultipleIndex=" + quickFinderMultipleIndex;
      self.location = "../Add-Document.aspx" + queryString;
   }
   else {
      var errorMessage = WebTwain3.ErrorString.indexOf('Success') == 0 ? '' : WebTwain3.ErrorString;
      alert("There was a problem uploading your scanned file(s). Please try again. If the problem persists, contact Support.\r\n" + errorMessage);
   }
}

Catherine · **Joined:** Tue Mar 08, 2005 12:23 am **Posts:** 1075

Hi,

Thanks for your feedback. We’ve reproduced the problem on our side. When you attempt to cancel a file transfer, the application will close all the requests and this leads to the response latency that you are experiencing.

Our developers are now looking into this issue and hope we can find a better way to optimize the operation. I will keep you updated on this issue.

Dynamsoft TWAIN Products

Browser hangs when clicking cancel on File Transfer

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