Using the code from this answer - Async two-way communication with Windows Named Pipes (.Net) - I'm finding the maximum number of connections/clients at any one time is 10.
In the crude example below (this uses multiple threads - same thing happens if multiple processes are used) clients 1 to 10 will start and run as normal. However clients 11 and 12 will block when 'ProcessData' is called, eventually throwing a TimeoutException.
public static void Start()
{
// Start Server
new Thread(new ThreadStart(Server.MainRun)).Start();
// Start Clients
for (int i = 1; i <= 12; i++)
{
Thread.Sleep(500);
Client c = new Client(i.ToString());
new Thread(new ThreadStart(c.Run)).Start();
}
}
// Create a contract that can be used as a callback
public interface IMyCallbackService
{
[OperationContract(IsOneWay = true)]
void NotifyClient();
}
// Define your service contract and specify the callback contract
[ServiceContract(CallbackContract = typeof(IMyCallbackService))]
public interface ISimpleService
{
[OperationContract]
string ProcessData();
}
[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)]
public class SimpleService : ISimpleService
{
public string ProcessData()
{
// Get a handle to the call back channel
var callback = OperationContext.Current.GetCallbackChannel<IMyCallbackService>();
callback.NotifyClient();
return DateTime.Now.ToString();
}
}
class Server
{
public static void MainRun()
{
// Create a service host with an named pipe endpoint
using (var host = new ServiceHost(typeof(SimpleService), new Uri("net.pipe://localhost")))
{
host.AddServiceEndpoint(typeof(ISimpleService), new NetNamedPipeBinding(), "SimpleService");
host.Open();
Console.WriteLine("Simple Service Running...");
Console.ReadLine();
host.Close();
}
}
}
class Client : IMyCallbackService
{
string _id;
public Client(string ID)
{
_id = ID;
}
public void Run()
{
Console.WriteLine("Starting client : " + _id);
// Consume the service
var factory = new DuplexChannelFactory<ISimpleService>(new InstanceContext(this), new NetNamedPipeBinding(), new EndpointAddress("net.pipe://localhost/SimpleService"));
var proxy = factory.CreateChannel();
Console.WriteLine(proxy.ProcessData());
Console.WriteLine("Client finished : " + _id);
}
public void NotifyClient()
{
Console.WriteLine("Notification from Server");
}
}
If the client closes the channel when done (factory.Close()) then all clients will be able to run.
I understand this question - Number of Clients that can connect to a Named Pipe - is very similar but suggests there is no low limit.
This suggests the limit is 10 on Windows XP and 2000 machines - http://msdn.microsoft.com/en-us/library/system.io.pipes.namedpipeclientstream.aspx - except this is happening on a Windows 8 machine and Windows 2008 server.
Is there a way to change this limit? Am I missing something obvious?
