Socket: Detect connection close

[Vladimir Panteleev]

On Sunday, 23 March 2014 at 20:12:38 UTC, nrgyzer wrote:
> Hi guys,
>
> I'm experimenting with sockets and having trouble to detect 
> when the remote side closes the connection. Here's my code:
>
> // Client:
> module client;
>
> import std.socket;
>
> void main()
> {
> 	TcpSocket s = new TcpSocket();
> 	s.connect(new InternetAddress("localhost", 8080));
> 	SocketStream ss = new SocketStream(s);
>
> 	for (int i= 0; i < 10; i++)
> 	{
> 		ss.write(1);
> 		ss.flush();
> 	}
> 	ss.socket.shutdown(SocketShutdown.BOTH);
> 	ss.close();
> }
>
> // Server:
> module server;
>
> import std.sdio;
> import std.socket;
>
> void main()
> {
>
> 	TcpSocket s = new TcpSocket(AddressFamily.INET);
> 	s.bind(new InternetAddress("localhost", 8080));
> 	s.blocking(false);
> 	s.listen(0);
>
> 	while(1)
> 	{
> 		try {
> 			Socket requestSocket = oSocket.accept();
> 			RequestThread rt = new RequestThread(requestSocket);
> 			rt.start();
> 		}
> 		catch (SocketAcceptException e)
> 		{
> 			Thread.yield();
> 		}
> 	}
>
> 	s.socket.shutdown(SocketShutdown.BOTH);
> 	s.close();
>
> }
>
> class RequestThread : Thread
> {
> 	private {
> 		__gshared Socket s;
>
> 		void run()
> 		{
> 			ubyte[1] buffer;
> 			while(s.isAlive)
> 			{
> 				s.receive(buffer);
> 				writeln("receiving");
> 			}
> 			writeln("client closed connection");
> 		}
>
> 	}
>
> 	public this(Socket socket)
> 	{
> 		super(&run);
> 		s = socket;
> 	}
> }
>
> I know... dirty (really) dirty code, but it works , except that 
> I'm in an endless loop and my server always prints "receiving". 
> I never see "client closed connection" although the client 
> sends only 10 int values. It seems that "s.isAlive" is always 
> true. How can I detect when the client closes the connection 
> (or how can I detect if the connection is broken)?

You can determine when the connection was closed on the remote 
side by checking if s.receive returns an empty array.