Determining if a PDF File with Cloud File path is Password protected or Not (path starting with https:\\)

Question

I am Using DotNetZip (from NuGet Package). This will normally work for a File path having ("@C:) but once if use the Cloud File Path like (https:) it is giving me IBM437 error. I can use this package but need to introduce some encoding which is the other problem.

I tried using SharpZipLib (another NuGet Package) but couldn’t find any information on internet related to it for a Cloud File Path. (http:).

I also tried Spire PDF but it throws File doesn't exist (Parameter 'fileName') error for password protected PDF.

URL’s for NuGet Packages - DotNetZip - https://www.nuget.org/packages/DotNetZip/ SharpZipLib- https://www.nuget.org/packages/SharpZipLib.NETStandard/

Please let me know if any more information is required.

Answer 1

You can try to download the .pdf file as a local temp file and then check could open it without a password. Just try the C# console app below:

using Spire.Pdf;
using System;
using System.IO;
using System.Net;

namespace PDFtest
{
    class Program
    {
        static void Main(string[] args)
        {
            var passwordPDFURL = "https://stantest1016.blob.core.windows.net/static/testPass.pdf";
            var noPassWordPDFURL = "https://stantest1016.blob.core.windows.net/static/testNoPass.pdf";

            var tempFilePath = "d:/temp/temp.pdf";

            //download file as a temp pdf file
            WebClient webClient = new WebClient();
            webClient.DownloadFile(passwordPDFURL, tempFilePath);
            try
            {
                PdfDocument pdf = new PdfDocument(tempFilePath);
                Console.WriteLine("PDF has been opened successfully with no password");
            }
            catch (Exception e) {

                Console.WriteLine(e.Message);
            }
            //remove temp file
            File.Delete(tempFilePath);
            
        }
    }
}

Test password protected .pdf Result:

Test no password protected .pdf Result: