Why does my code to download files produce corrupted PDFs?

Question

I have a problem when downloading PDF files with the following code:

WebClient client = new WebClient();
client.DownloadFile(remoteFilename, localFilename);

Whereas other files are downloaded successfully, when I download and save a PDF document it shows a document repaired error when I try to open it.

My problem is after downloading a pdf file and saving it as a pdf document thro above mentioned code. wen I try to open it shows document repaired error. — Syed Mudhasir, Jan 10 '11 at 11:11
I hope this below link 'll help you... http://stackoverflow.com/questions/10829168/can-we-use-response-flush-instead-of-response-end/17038408#17038408 — Viishnuu, Jun 11 '13 at 07:22
I don't think this question is answerable because so little information is provided. Through its use of `WebClient` and the term "download(ing)" it's clear this is about _client_-side code, so why are so many answers showing _server_-side code (and getting upvoted for it, too)? Where is the misunderstanding? — Lance U. Matthews, Feb 04 '20 at 19:06

score 7 · Answer 1 · answered Jan 10 '11 at 07:40

7

check this method , hope that helps

        public static void DownloadFile(HttpResponse response,string fileRelativePath)
    {
        try
        {
            string contentType = "";
            //Get the physical path to the file.
            string FilePath = HttpContext.Current.Server.MapPath(fileRelativePath);

            string fileExt = Path.GetExtension(fileRelativePath).Split('.')[1].ToLower();

            if (fileExt == "pdf")
            {
                //Set the appropriate ContentType.
                contentType = "Application/pdf";
            }

            //Set the appropriate ContentType.
            response.ContentType = contentType;
            response.AppendHeader("content-disposition", "attachment; filename=" + (new FileInfo(fileRelativePath)).Name);

            //Write the file directly to the HTTP content output stream.
            response.WriteFile(FilePath);
            response.End();
        }
        catch
        {
           //To Do
        }
    }

answered Jan 10 '11 at 07:40

Mahmoud Farahat

5,364
4
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1

you have to set contentType = "Application/pdf"; to ensure that downloaded file is correct PDF file – Mahmoud Farahat Jan 10 '11 at 07:43
Thanks Mahmoud I tried this but i am getting the following error : The type or namespace name 'HttpResponse' could not be found (are you missing a using directive or an assembly reference?) – Syed Mudhasir Jan 10 '11 at 11:08
@Syed Mudhasir. You should add Reference 'System.Web' on your References project – BantenCity Jan 10 '11 at 12:42
I did add that line "using Systems.Web;" but i get same error – Syed Mudhasir Jan 10 '11 at 13:18
@Mahmoud:web application – Syed Mudhasir Jan 10 '11 at 13:18
@syed :ok , please try full name System.Web.HttpResponse – Mahmoud Farahat Jan 10 '11 at 13:28
@syed : please don't forget to add system.web refrences (right click on refrences > add refrence) – Mahmoud Farahat Jan 10 '11 at 13:38
Thank u so much dos errors r eliminated. But think I am not callin d func properly : DownloadFile("http://www.neevia.com / PDF / cluster.pdf", "d:/clustering_check.pdf"); pls giv me an example of the 2 params dat i hav to pass to cal dis func – Syed Mudhasir Jan 10 '11 at 15:09
I am gettin the followin error :Argument '1': cannot convert from 'string' to 'System.Web.HttpResponse' – Syed Mudhasir Jan 10 '11 at 15:18
@syed : ok , you are now in a webpage ".aspx file" in code behind call this method ex : DownloadFile(Response,"File_Path") – Mahmoud Farahat Jan 10 '11 at 15:40
@Mahmoud: how & wer do I put the url :"neevia.com / PDF / cluster.pdf" – Syed Mudhasir Jan 11 '11 at 06:16
@syed : hmmm.. , i think there is misunderstanding. , this code is to put in your site where visitors can click a link and download the file , do you want to do that , or you want to download the file from other site ??!!! – Mahmoud Farahat Jan 11 '11 at 06:58
This is server-side code whereas the question is asking about the use of `WebClient`, which is client-side. – Lance U. Matthews Feb 04 '20 at 19:02

Raaghav · Answer 2 · 2014-12-15T03:42:19.210

2

Please try the Following code sample to download .pdf file.

 Response.ContentType = "Application/pdf"; 
 Response.AppendHeader("Content-Disposition", "attachment; filename=Test_PDF.pdf"); 
 Response.TransmitFile(Server.MapPath("~/Files/Test_PDF.pdf")); 
 Response.End();

edited Dec 15 '14 at 03:42

answered May 18 '12 at 12:47

Raaghav

3,000
1
23
21

This is server-side code whereas the question is asking about the use of `WebClient`, which is client-side. This is also essentially the same thing as [@MahmoudFarahat's answer](https://stackoverflow.com/a/4644637/150605) from over a year earlier. – Lance U. Matthews Feb 04 '20 at 18:59

score 1 · Answer 3 · edited Apr 06 '12 at 14:20

1

@Syed Mudhasir: Its just a line :)

client.DownloadFileAsync(new Uri(remoteFilename, UriKind.Absolute), localFilename);

It will download pdf files. :)

edited Apr 06 '12 at 14:20

Sergey Glotov

20,200
11
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98

answered Apr 06 '12 at 14:13

JAVA

11
1

score 0 · Answer 4 · answered Dec 15 '18 at 20:36

None of these solutions worked for me, or were not complete. Maybe this post was old and newer versions of .NET made it easier? Anyway, the following small code did the job for me so nicely:

  static async Task DownloadFile(string url, string filePath)
  {
     using (var wc = new WebClient())
        await wc.DownloadFileTaskAsync(url, filePath);
  }

And here how you can call the method:

Task.Run(async () => { await DownloadFile(url, filePath); }).Wait();

score 0 · Answer 5 · answered Feb 28 '19 at 21:37

0

    public void DownloadPdf(String downloadLink, String storageLink)
    {
        using (WebClient wc = new WebClient())
        {
            wc.DownloadFile(downloadLink, storageLink);
        }
        Console.Write("Done!");
    }

    static void Main(string[] args)
    {
        Program test = new Program();
        test.DownloadPdf("*PDF file url here*", @"*save location here/filename.pdf*");
        Console.ReadLine();
    }

Make sure you add: using System.Net;

answered Feb 28 '19 at 21:37

Raghu Raj Rai

21
3

This is essentially the same code as in the question only wrapped in a method. Why would this code be expected to produce a readable file when the code in the question doesn't? – Lance U. Matthews Feb 04 '20 at 18:56

score -1 · Answer 6 · answered Feb 04 '20 at 18:38

public void DownloadTeamPhoto(string fileName)
{
  string mimeType = MimeAssistance.GetMimeFromRegistry(fileName);
  Response.ContentType = mimeType;
  Response.AppendHeader("Content-Disposition", "attachment; filename=" + 
  Path.GetFileName(basePath + fileName)); //basePath= @"~/Content/
  Response.WriteFile(basePath + fileName); //basePath= @"~/Content/
  Response.End();

}

public static string GetMimeFromRegistry(string Filename)
{
  string mime = "application/octetstream";
  string ext = System.IO.Path.GetExtension(Filename).ToLower();
  Microsoft.Win32.RegistryKey rk = 
  Microsoft.Win32.Registry.ClassesRoot.OpenSubKey(ext);

  if (rk != null && rk.GetValue("Content Type") != null)
     mime = rk.GetValue("Content Type").ToString();

  return mime;
}

What is this even doing and how does it apply to the question? It seems to be figuring out the MIME type, so is this supposed to be run server-side? How do you know the server is running Windows and under the control of the downloading party? Where is the `WebClient` and file transfer? — Lance U. Matthews, Feb 04 '20 at 18:42

score -3 · Answer 7 · edited Feb 24 '18 at 01:19

-3

This worked for me:

string strURL = @"http://192.168.1.xxx/" + sDocumento;
WebClient req = new WebClient();
HttpResponse response = HttpContext.Current.Response;
response.Clear();
response.ClearContent();
response.ClearHeaders();
response.Buffer = true;
response.AddHeader("Content-Disposition", "attachment;filename=\"" + sDocumento + "\"");
byte[] data = req.DownloadData(strURL);
response.BinaryWrite(data);
response.End();

edited Feb 24 '18 at 01:19

derloopkat

6,232
16
38
45

answered Feb 23 '18 at 22:03

Eric Correa

1

If you remove the references to the `System.Web` namespace, which was not specified in the question and implies this is server-side code, this becomes simply `WebClient req = new WebClient(); byte[] data = req.DownloadData(strURL);`, which is not all that different than what's in the question. So how does this solve the problem? – Lance U. Matthews Feb 04 '20 at 18:52

Why does my code to download files produce corrupted PDFs?

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