file extension not downloading in ASP.NET 3.5 forms

Question

I'm really baffled because on one website, my code works perfectly, and on another website, it doesn't.

The file downloads without the extension, but when I rename the downloaded file to include the extension (I add .pdf to the filename), it opens correctly as a PDF. I am 100% sure bytes and filename are correct, and filename is report.pdf.

Here's the original code:

    private void downloadByteStreamAsFile(Byte[] bytes, String fileName)
    {
        System.Web.HttpResponse response = System.Web.HttpContext.Current.Response;
        response.Clear();

            //response.Flush(); //comment this or else no file returned
            response.AddHeader("Content-Type", "binary/octet-stream");
            response.AddHeader("Content-Disposition",
                "attachment; filename=" + fileName + "; size=" + bytes.Length.ToString());

            response.BinaryWrite(bytes);
            response.Flush();
            response.End();

        }
    }

I also tried:

using output stream Trying to stream a PDF file with asp.net is producing a "damaged file"
removing the space after the semicolon in Content-Disposition file extensions lost between browsers in asp.net c# application
"attachment; filename=" + fileName + ".PDF; size=" + bytes.Length.ToString()); (so now the file should be named report.pdf.PDF but it is still only named report)

Please help

Update: Code works fine in IE and Chrome, only Firefox has this issue of losing the file extension

try to use `response.AddHeader("Content-Type", "application/pdf");` — Iłya Bursov, Aug 02 '15 at 04:35
@Lashane : ( Nope, doesn't help. But I did figure out it is firefox only — rlb.usa, Aug 02 '15 at 04:41
possible duplicate of [Why Does FireFox Not Include the .xml Extension when Downloading a File?](http://stackoverflow.com/questions/1120599/why-does-firefox-not-include-the-xml-extension-when-downloading-a-file) — rlb.usa, Aug 02 '15 at 04:47
Here is the answer http://stackoverflow.com/questions/1120599/why-does-firefox-not-include-the-xml-extension-when-downloading-a-file — rlb.usa, Aug 02 '15 at 04:47

score 2 · Answer 1 · answered Aug 02 '15 at 04:52

Try putting the filename in quotes.

response.AddHeader(
    "Content-Disposition",
    "attachment; filename=\"" + fileName + "\"; size=" + bytes.Length.ToString());`

If that works, then see if this still works for IE and Chrome and Safari. If not, add an if statement to conditionally add the quotes.

score 2 · Accepted Answer · answered Aug 26 '15 at 15:57

This threw me for a real loop, but it turned out that only PDF files weren't being downloaded correctly, and that was because of the Content-Type being set. I probably could have refactored my code differently, but I liked coding it this way best because it was easiest for me to understand and debug. Here's my fixed method:

    private void downloadByteStreamAsFile(Byte[] bytes, String fileName)
    {
        fileName = fileName.Replace(" ", "_");

        System.Web.HttpResponse response = System.Web.HttpContext.Current.Response;
        response.Clear();

       if( fileName.Contains(".pdf")){
            fileName = HttpUtility.UrlEncode(fileName);
            //response.Flush(); //comment this or else no file returned
            response.AddHeader("Content-Type", "application/pdf");
            response.AddHeader("Content-Disposition",
                "attachment; filename=" + fileName + "; size=" + bytes.Length.ToString());

            response.BinaryWrite(bytes);
            response.Flush();
            response.End();
        } else {
            //response.Flush(); //comment this or else no file returned
            response.AddHeader("Content-Type", "binary/octet-stream");
            response.AddHeader("Content-Disposition",
                "attachment; filename=" + fileName + "; size=" + bytes.Length.ToString());

            response.BinaryWrite(bytes);
            response.Flush();
            response.End();

        }
    }

score 0 · Answer 3 · answered Feb 23 '17 at 08:02

If someone is using IIS 7.5 with Windows Server 2008 R2 follow the code snippet below...

The code works cross browser and handles "Network Failed error" for chrome browser > 51 update

     // CSV Generic List    
         CSVExportGeneric<BookFxDownload> _csv = new CSVExportGeneric<BookFxDownload>(Download);
            // Convert to byte array
                                byte[] a = _csv.ExportToBytes().ToArray();
    // the lines are supposed to be in the same order
                                Response.Clear();
                                Response.Buffer = true;
                                Response.ClearHeaders();
                                Response.ClearContent();

                                //Response.AppendHeader("content-disposition", fileName);
                                Response.ContentType = "application/csv";
                                Response.AddHeader("Content-Length", a.Length.ToString());
//fileName = <yourname>.<extension>
                                Response.AppendHeader("content-disposition", "attachment; filename=" +"\"" + fileName + "\"");
                                Response.Charset = "";
                                Response.OutputStream.Write(a, 0, a.Length);
                                Response.Flush();
                                Response.Close();

file extension not downloading in ASP.NET 3.5 forms

3 Answers3