I have an application that needs to download several files in a row in succession (sometimes a few thousand). However, what ends up happening when several files need to be downloaded is I get an exception with an inner exception of type SocketException and the error code 10048 (WSAEADDRINUSE). I did some digging and basically it s because the server has run out of sockets (and they are all waiting for 240s or so before they become available again) - not coincidentally it starts happening around the 1024 file range. I would expect that the HttpWebRequest/ServicePointManager would be reusing my connection, but apparently it is not (and the files are https, so that may be part of it). I never saw this problem in the C++ code that this was ported from (but that doesn t mean it didn t ever happen - I d be surprised if it was, though).
I am properly closing the WebRequest object and the HttpWebRequest object has KeepAlive set to true by default. Next my intent is to fiddle around with ServicePointManager.SetTcpKeepAlive(). However, I can t see how more people haven t run into this problem.
Has anyone else run into the problem, and if so, what did you do to get around it? Currently I have a retry scheme that detects this error and waits it out, but that doesn t seem like the right thing to do.
Here s some basic code to verify what I m doing (just in case I m missing closing something):
WebRequest webRequest = WebRequest.Create(uri);
webRequest.Method = "GET";
webRequest.Credentials = new NetworkCredential(username, password);
WebResponse webResponse = webRequest.GetResponse();
try
{
using(Stream stream = webResponse.GetResponseStream())
{
// read the stream
}
}
finally
{
webResponse.Close()
}