Question

I am uploading thousands of files to a server.

The server connection breaks allot, so I need a way for this console application to be able to recover if the connection fails for a few seconds etc.

My application is simple, it just gets all the files in the c:\uploads folder and then uses a web service to upload the files to the server.

so:

foreach(string file in files)
{
UploadToServer(file);
}

How can I make this so it re-covers in the event of a connection failure? (failures usually last just a few seconds)

Answer 1

Use a little helper method that retries the upload several times before throwing in the towel. For example:

static void UploadFile(string file) {
  for (int attempt = 0; ; ++attempt) {
    try {
      UploadToServer(file);
      return;
    }
    catch (SocketException ex) {
      if (attempt < 10 && (
          ex.SocketErrorCode == SocketError.ConnectionAborted ||
          ex.SocketErrorCode == SocketError.ConnectionReset ||
          ex.SocketErrorCode == SocketError.Disconnecting ||
          ex.SocketErrorCode == SocketError.HostDown)) {
        // Connection failed, retry
        System.Threading.Thread.Sleep(1000);
      }
      else throw;
    }
  }
}

Tweak the exception handling code as needed.