Save original document at the server side

28 Feb 20262 minutes to read

The Syncfusion® PDF Viewer can persist the original PDF file on the server by redirecting the download action to a custom controller method. This approach is useful for audit trails, archival policies, or downstream processing that requires access to the unmodified document after the user views it.

Follow these steps to enable server-side persistence:

Step 1: Create a PDF Viewer project by following the ASP.NET Core getting started guide to configure the necessary scripts, Razor markup, and controller endpoints.

Step 2: Add a button to the user interface that overrides the download action before invoking the viewer’s download method. The script below targets the serverActionSettings.download endpoint, triggers the download, and then restores the default action.

<button onclick="save()">Save Document</button>

<script>
    function save() {
        var pdfViewer = document.getElementById('pdfviewer1').ej2_instances[0];
        pdfViewer.serverActionSettings.download = "SaveDocument";
        pdfViewer.download();
        pdfViewer.serverActionSettings.download = "Download";
    }
</script>

Step 3: Implement the SaveDocument action in the PDFViewerController.cs. Use PdfRenderer.GetDocumentAsBase64 to retrieve the original file data and write it to the server’s disk.

public ActionResult SaveDocument([FromBody] Dictionary<string, string> jsonObject)
{
    PdfRenderer pdfviewer = new PdfRenderer(_cache);
    string documentBase = pdfviewer.GetDocumentAsBase64(jsonObject);
    string base64String = documentBase.Split(new string[] { "data:application/pdf;base64," }, StringSplitOptions.None)[1];
    if (base64String != null || base64String != string.Empty)
    {
        byte[] byteArray = Convert.FromBase64String(base64String);

        MemoryStream ms = new MemoryStream(byteArray);
        var path = _hostingEnvironment.ContentRootPath;
        System.IO.File.WriteAllBytes(path + "/ouptut.pdf", byteArray);
    }
    return Content(string.Empty);
}

Download the sample: How to save original document at the server side

NOTE

Ensure the controller has the necessary write permissions for the target directory. It is also recommended to validate user authorization before saving files and to manage file naming conventions to prevent overwriting existing data.