Re: Newcomer's CAsyncSocket example: trouble connecting with other clients

From:

Hector Santos <sant9442@gmail.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Thu, 13 May 2010 18:21:23 -0400

Message-ID:

<hshu1u$2361$1@news.ett.com.ua>

Ok, I downloaded and tested Joey's AsyncServer application.

You're question is why you are seeing:

    ?.?.?.? [?] Closed

Is that correct?

The reason is that the socket is closed by the time the
GetPeerPrefix() is called in DoClose() thus the socket peer binding
information is already invalid.

Here is the fix based on the idea that the peer information does not
change during the duration of the connection.

1) In CONNECTS.H add a protected member:

  protected:
     CString PeerInfo;

2) In CONNECTS.CPP, add the following lines to the top and bottom of
GetPeerInfo() so it looks like this:

CString CConnectSoc::GetPeerPrefix()
    {
      if (PeerInfo != "") return PeerInfo; // HLS FIX
      CString ip;
      UINT port;
      GetPeerName(ip, port);
      if(ip.IsEmpty())
          { /* no name */
           return _T("?.?.?.? [?]");
          } /* no name */
      CString s;
      s.Format(_T("%s [%u]"), ip, port);
      PeerInfo = s; // HLS FIX
      return s;
    } // CConnectSoc::GetPeerPrefix

In other words, once the PeerInfo is set, it no longer needs to get it
again, it it good for the entire session. the IP and PORT will not
ever change during this session.

That will eliminate this minor logging issue.

Now, again with minimum review of this code, I don't see it doing
anything useful for you with a client application.

Add this to test a simple "Echo" server:

1) Need the top of CONNECTS.CPP add:

#define HLS_TEST_ECHO_SERVER

2) In the CConnectSoc::Receive() function, add this before the return
result line:

#ifdef HLS_TEST_ECHO_SERVER
    Send(Buf,result,0);
#endif

Now, you can test this with any TTY or telnet application, whatever
you type, AsyncServer will echo it back.

Hope this helps

---
HLS

stephen park wrote:

I don't know what Joe's program is, but the above is correct when you
are talking to a telnet-like like server. I have no reason to
question Joe's CAsyncServer, but I have not try it to see what it
suppose to do for you.

What part are you trying to make work? What are you looking for?

What I would do is begin with the basics of writing a TTY client. If
you are just learning sockets, you need to begin with the
basics, which comes with "mistakes" and trial and error process.

Try this TTY() function:

void tty(String ^hostname, int port)
{

    Console::WriteLine("* Connecting");

    TcpClient^ c;

    try {
        c = gcnew TcpClient(hostname,port);
    } catch(SocketException ^e) {
        Console::WriteLine(L"- Connect Error {0}",e->ErrorCode);
        Console::ReadKey();
        return;
    }

    // use 100ms timeout for reader
    c->Client->ReceiveTimeout = 100;

    array<Byte>^ bytes = gcnew array<Byte>(1024);
    NetworkStream ^cio = c->GetStream();

    while (1) {
        if (Console::KeyAvailable) {
            ConsoleKeyInfo^ key = Console::ReadKey(true);
            if (key->Key == ConsoleKey::Escape) break;
            try {
                cio->WriteByte(key->KeyChar);
            } catch( Exception ^e) {
                break;
            }
        }
        try {
            int nBytes = c->Client->Receive( bytes );
            for (int i=0; i < nBytes; i++) {
                Console::Write("{0}",(wchar_t)bytes[i]);
            }
        } catch( SocketException ^e) {
            if (e->ErrorCode == 10054) {
                Console::WriteLine(L"! Disconnect");
                break;
            }
        }
    }
    c->Close();
    Console::WriteLine("* Closed");
    Console::ReadKey();

}

Interesting - this code doesn't work either. Dr. Newcomer's server
says it got a connection, but when I type stuff in nothing gets sent.
I can CTRL-C and then the server says its disconnected. Sooo ...
apparently nothing is getting sent?

I did try calling the .net versions of shutdown() and the
NetworkStream class even has a flush() function, although the doc says
that its reserved for future use. I called it anyway in my code but
still nothing got sent.

Interestingly enough, if I try telnetting to Dr. Newcomer's server I
get the same result as the tty code above - it says its connected, but
nothing gets sent? I could type stuff in, then hit Ctrl-D, Ctrl-G,
whatever Ctrl combo that might hopefully say I'm done sending stuff,
but nothing goes ...