Question

I am trying to download files through webclient and the code is like the one given below. The problem is that if I get continuous 404 response alot of times, my server reaches to 100% and viewing the event log tells that stack overflow happened. Here the “count” variable is to avoid 0 byte files and count404 is for 404 responses.

    int count = 0; int count404 = 0;
    public Stream DownloadFileThroughWebClient(string strFilePath)
    {
        try
        {
            if (count >= 120 || count404 >= 30)
            {
                count = 0;
                count404 = 0;
                return null;
            }
            System.Threading.Thread.Sleep(1000);
            System.Net.WebClient wc = new System.Net.WebClient();
            var v = wc.DownloadData(strFilePath);
            Stream FileToSave = new MemoryStream(v);
            byte[] bytes = new byte[FileToSave.Length];
            int numBytesToRead = (int)FileToSave.Length;
            if (numBytesToRead > 0)
            {
                count = 0;
                count404 = 0;
                return FileToSave;
            }
            else
            {
                count++;
                count404 = 0;
                return DownloadFileThroughWebClient(strFilePath);
            }
        }
        catch (Exception ex)
        {
            count++;
            count404++;
            return DownloadFileThroughWebClient(strFilePath);
        }
    }

Thanks in advance.

Answer 1

Try this (without using recursion and counts the 404s correctly):

public Stream DownloadFileThroughWebClient(string strFilePath)
{
    int count = 0; 
    int count404 = 0;

    while (count < 120 && count404 < 30)
    {
        try
        {
            byte[] v;
            using (var wc = new WebClient())
            {
                v = wc.DownloadData(strFilePath);
            }

            if (v.Length > 0)
            {
                return new MemoryStream(v);
            }

            count++;
            count404 = 0;
        }
        catch (WebException ex)
        {
            count++;
            var httpWebResponse = ex.Response as HttpWebResponse;
            if (httpWebResponse != null && httpWebResponse.StatusCode == HttpStatusCode.NotFound)
            {
                count404++;
                // you may wanna break out of the loop here since there's no point in continuing 
            }
        }
        catch (Exception ex)
        {

        }
    }
    return null;
}