Question

I need basic file downloading capabilities in my app and I cannot use WebClient.DownloadFile [1]. Is this (naïve?) implementation of a DownloadFile method enough? Are there any pitfalls that I don’t address with this implementation?

public static void DownloadFile(String url, String destination)
{
    using (var request = (HttpWebRequest)WebRequest.Create(url))
    {
        request.Method = "GET";
        request.Timeout = 100000; // 100 seconds

        using (var response = request.GetResponse())
        {
            using (var responseStream = response.GetResponseStream())
            {
                using (var fileStream = File.Open(destination,
                                                  FileMode.Create,
                                                  FileAccess.Write,
                                                  FileShare.None))
                {
                    var MaxBytesToRead = 10 * 1024;
                    var buffer = new Byte[MaxBytesToRead];
                    var totalBytesRead = 0;
                    var bytesRead = responseStream.Read(buffer,
                                                        0,
                                                        MaxBytesToRead);

                    while (bytesRead > 0)
                    {
                        totalBytesRead += bytesRead;
                        fileStream.Write(buffer, 0, bytesRead);
                        bytesRead = responseStream.Read(buffer,
                                                        0,
                                                        MaxBytesToRead);
                    }
                }
            }
        }
    }
}

Thanks!

[1] .Net Compact Framework…

Answer 1

You’re keeping track of totalBytesRead, but I can’t see it used anywhere.

Since Method = "GET" is the default, I don’t see anything that’s specific to HTTP. If you remove the (HttpWebRequest) cast and the Method = line then you’ll gain the ability to download over other protocols, such as FTP. Currently the code will throw an exception if somebody provides a URL other than http://.