• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (87/87) Aug 26 2013 The following simple socket example is trying to cleanup after itself,
• dnewbie (2/4) Aug 26 2013 It works on Windows7, no need to wait.
• Regan Heath (36/43) Aug 27 2013 =
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (5/7) Aug 27 2013 That worked. I copied the following line from std/socket.d:

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

The following simple socket example is trying to cleanup after itself, 
except the bind() call. As I repeat in the QUESTION comment below, I 
have read the man page of bind and I know that I need to unlink a path. 
How can I get that path?

The program waits on localhost:8080, receives N number of data and 
responds with "Hello World!".

The problem is, currently the program apparently leakes some resources. 
It cannot be started a second time for 8080 still being in use, unless 
you wait for several seconds, presumably until the OS does the cleanup.

import std.stdio;
import std.socket;
import std.string;

enum port = 8080;

void main()
{
     server();
}

void server()
{
     // Prepare the socket
     auto listener = new TcpSocket();
     scope (exit) {
         writefln("Shutting down and closing the listener");
         listener.shutdown(SocketShutdown.BOTH);
         listener.close();
     }

     /*
      * The port to listen to
      *
      * Note that the following perhaps naive code does not work on OSX. Try
      * the following line instead:
      *
      *   listener.bind(new InternetAddress(port));
      */
     Address[] addresses = getAddress("localhost", port);
     writefln("Addresses: %s", addresses);
     auto address = addresses[0];
     writefln("Address: %s", address);
     listener.bind(address);
     scope (exit) {
         /*
          * QUESTION: What to do here?
          *
          * According to 'man bind', the path that represents the 
address must
          * be unlink'ed. However, the path seems to be available only 
through
          * UnixAddress.path but UnixAddress is not available by default 
and it
          * is not convenient to use (e.g. it does not have a 
constructor that
          * takes the port value).
          */
     }

     // Wait for the client
     listener.listen(1);
     writeln("Waiting for the client");

     // Accept the connection
     Socket connection = listener.accept();
     scope (exit) {
         writefln("Shutting down and closing the client connection %s",
                  connection.remoteAddress());
         connection.shutdown(SocketShutdown.BOTH);
         connection.close();
     }

     ubyte[1000] buffer;
     bool isAllReceived = false;

     while (!isAllReceived) {
         const received = connection.receive(buffer);

         if (received == Socket.ERROR) {
             writeln("READ ERROR");
             break;

         } else {
             writefln("Received %s bytes; as string: %s",
                      received, cast(string)buffer[0..received]);
         }

         isAllReceived = (received < buffer.length);
     }

     if (isAllReceived) {
         enum header =
             "HTTP/1.0 200 OK\nContent-Type: text/html; charset=utf-8\n\n";

         string response = header ~ "Hello World!\n";
         connection.send(response);
     }
}

Thank you,
Ali

"dnewbie" <run3 myopera.com> writes:

On Tuesday, 27 August 2013 at 03:30:11 UTC, Ali Çehreli wrote:
 It cannot be started a second time for 8080 still being in use, 
 unless you wait for several seconds

It works on Windows7, no need to wait.

"Regan Heath" <regan netmail.co.nz> writes:

On Tue, 27 Aug 2013 04:30:10 +0100, Ali =C7ehreli <acehreli yahoo.com> w=
rote:
 The following simple socket example is trying to cleanup after itself,=

  =

 except the bind() call. As I repeat in the QUESTION comment below, I  =

 have read the man page of bind and I know that I need to unlink a path=

.  =

 How can I get that path?

That example is for AF_UNIX domain sockets.  TcpSocket is an AF_INET  =

domain socket.  In AF_INET there is no 'path' and there is nothing you  =

need to do to cleanup after bind - other than close the socket.  I do no=
t  =

believe a shutdown is required for a listening socket - tho don't quote =
me  =

on that.

 The problem is, currently the program apparently leakes some resources=

.  =

 It cannot be started a second time for 8080 still being in use, unless=

  =

 you wait for several seconds, presumably until the OS does the cleanup=

.

Correct.  And this time varies by platform, as dnewbie mentions on Windo=
ws  =

you can re-use immediately.

You could set the REUSE option on the socket prior to 'bind', this would=
  =

allow you to bind again while the previous socket was in cleanup.

The other thing which might be affecting things is..

Take a look at:
http://linux.die.net/man/7/socket

Specifically "SO_LINGER".  This socket option controls whether and how  =

long a socket will linger after it is closed.  I am not sure what the  =

linux defaults are for that, but it may be set to linger intentionally. =
  =

You could use getsockopt to obtain the LINGER default values and see.

Also.. the sentence "When the socket is closed as part of exit(2), it  =

always lingers in the background." made me think, when does scope(exit) =
 =

fire?  Does it occur as part of exit in your example?  Does manually  =

calling shutdown/close on the listening socket resolve the issue.

Regan

-- =

Using Opera's revolutionary email client: http://www.opera.com/mail/

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 08/27/2013 02:02 AM, Regan Heath wrote:

 You could set the REUSE option on the socket prior to 'bind', this would
 allow you to bind again while the previous socket was in cleanup.

That worked. I copied the following line from std/socket.d:

     listener.setOption(SocketOptionLevel.SOCKET,
                        SocketOption.REUSEADDR, true);

Ali