WebClient and FtpWebRequest Both Hanging (Timeout)

Question

I'm trying to download a file from a FTP site that uses Passive Mode. I've tried both the FtpWebRequest methods and the WebClient.DownloadFile and DownloadFileAsync methods.

Most recently, my code looks like:

using (var client = new WebClient())
{
    client.Proxy = new WebProxy();
    client.Credentials = credentials;
    client.DownloadFileCompleted += client_DownloadFileCompleted;
    client.DownloadFileAsync(new Uri(remotePath), localPath);
}

and is wrapped in a method DownloadFile. In the async handler I get the next item and (recursively) make a call to DownloadFile method again, and so on and so on until I get to the last item.

Almost every single time, every method I use, I get through 6 files and the 7th errors out. Only one time did it get through all of the files in the list and I could not replicate it again. The file counts are about 100 and file sizes are about 30 - 120k a piece. Strangely enough, often I will see the file count in my local folder hang on the 7th item, but if I let the Worker Process run in the background and then come back a few minutes later and shut down IIS express or the VS Web Server, the files will show up. It's too unpredictable, though, and cannot be used in production as is.

I also tried the FTP LIB library on CodePlex and had the same problem.

It seems like something on their end is closing my connection out.

Answer 1

I have had a similar problem. In my case I needed to download many small files from many folders on a Linux server. Sys-admin bloke suggested I put in a 3 second delay between each batch. It greatly reduced the number of errors.