How to download files with filename containing special characters using .Net WebClient

Question

I am getting an error “400 – Bad Request” while using .Net WebClient to download files with filename containing certain characters:

For example if the file is named: 5L1XQE6FTest #.mp4 ; this generates an error.

If I remove the # sign the file is downloaded fine:

Here is my code:

public ActionResult DownloadVideoFile(string filepath)
{
    try
    {              
        filepath = "http://localhost:1832/VideoUploads/" + filepath;
        var type = new System.Net.Http.Headers.MediaTypeHeaderValue("application/octet-stream");
        var path = Path.GetFileName(filepath);

        using (var client = new WebClient())
        {           
            var buffer = client.DownloadData(filepath);
            return File(buffer, type.ToString(), path);
        }
    }
    catch (Exception e)
    {
        var test = e.Message;
    }

    return null;    
}

I have no control over the filename that I am trying to download as files are user submitted.

When I Url encode the file I get a "Cannot find file" error:

using (var client = new WebClient())
{
    filepath = Url.Encode(filepath);
    var buffer = client.DownloadData(filepath);
    return File(buffer, type.ToString(), path);
}

Here is the path after URL encoding:

C:\\Program Files (x86)\\IIS Express\\http%3a%2f%2flocalhost%3a1832%2fVideoUploads%2f5L1XQE6FTest+%23.mp4'

How can I resolve the Bad Request error while downloading files with special or reserved characters?

Answer 1

At what point in your code is the exception actually being raised? WebClient should have no problem downloading any validly named resource (valid as in it actually functions as a URL). If the URL you're trying to use is in fact not a valid URL (because of the odd file name), URL encoding it might be sufficient to fix the issue.

However, you're also using the bad file name later as a parameter to File , and that's probably a bad idea. If this is where the exception is being raised, simply constructing your own filename, without the problematic characters, should be enough to solve the problem.

Answer 2

请用＃23替换＃，它将起作用。