DownloadFileAsync downloading corrupted file

Question

I am trying to build a download class. Files from GitHub download fine, but if I download ROBLOX assets (http://www.roblox.com/asset/?id=1286103 as an example), it downloads a file filled with garbage data, when it should download a ROBLOX mesh file that starts with the header "version 1.00".

    public void InitDownload(string additionalText = "")
    {
        downloadOutcomeAddText = additionalText;

        saveFileDialog1 = new SaveFileDialog()
        {
            FileName = fileName,
            //"Compressed zip files (*.zip)|*.zip|All files (*.*)|*.*"
            Filter = fileFilter,
            Title = "Save " + fileName
        };

        if (saveFileDialog1.ShowDialog() == DialogResult.OK)
        {
            try
            {
                using (WebClient wc = new WebClient())
                {
                    wc.DownloadProgressChanged += wc_DownloadProgressChanged;
                    wc.DownloadFileAsync(new Uri(fileURL), saveFileDialog1.FileName);
                }

                downloadOutcome = "File " + Path.GetFileName(saveFileDialog1.FileName) + " downloaded!" + downloadOutcomeAddText;
            }
            catch (Exception ex)
            {
                downloadOutcome = "Error when downloading file: " + ex.Message;
            }
        }
    }

    void wc_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
    {
        downloadProgress.Value = e.ProgressPercentage;
    }

`it downloads a file filled with garbage data` please show the `garbage data` — zaitsman, Nov 09 '19 at 01:17
here's an image of the garbage data [1](https://i.imgur.com/6di6wDq.png) and here's one of how it SHOULD look [2](https://i.imgur.com/KxwIQDP.png) — Michael Hart, Nov 09 '19 at 01:24
https://stackoverflow.com/questions/2973208/automatically-decompress-gzip-response-via-webclient-downloaddata — Hans Passant, Nov 09 '19 at 01:31

Paul Wheeler · Accepted Answer · 2019-11-09T01:28:42.043

It looks like the ROBLOX API is responding with gzip encoded data and evidently WebClient.DownloadFileAsync doesn't default to automatically decompressing the response body. For more information and a somewhat dated example of how to handle this see: https://blog.codinghorror.com/netwebclient-and-gzip/.

Update: This Stack Overflow answer may also be helpful (it is simpler and doesn't require a 3rd party library): Uncompressing gzip response from WebClient

DownloadFileAsync downloading corrupted file

1 Answers1