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

From:

Hector Santos <sant9442@gmail.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Wed, 12 May 2010 20:19:56 -0400

Message-ID:

<hsfgk5$154q$1@news.ett.com.ua>

stephen park wrote:

Wow, I really hate turning this into a .net discussion in an mfc
group, but I built a CLR console app and this just doesn't send
anything to the Newcomer server: (code in its entirety)

#include "stdafx.h"

using namespace System;
using namespace System::Net::Sockets;

int main(array<System::String ^> ^args)
{
    TcpClient^ c = gcnew TcpClient( server,port );
    String^ msg = "hello, world!";
    array<Byte>^data = Text::Encoding::ASCII->GetBytes( msg );
    c->Client->Send( data );

    Console::ReadKey();

    c->Close();

    return 0;
}

The server says its connected, but when I hit a key the server says
?.?.?.? [?] Closed

with the "Last Received Message" edit box empty.

Doing the same thing with csocket and an mfc console app does the same
thing. Just what the heck am I missing in both?

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();
}

You can try this against any TELNET like server, including any TELNET,
SMTP, FTP, NNTP, POP3, IMAP server, etc.

Here are a few telnet servers:

     bbs.winserver.com port=23
     beta.winserver.com port=23

Even SMTP, FTP or NNTP servers, try these:

     msforums.winserver.com port=119
     news.microsoft.com port119

You know, you can make the tty() function a SERVER by changing the
connect() which you are implicitly doing with the constructor

    gcnew TcpClient(hostname,port)

above and replacing it with SOCKET functional calls equivalent in
C/C++.NET for:

     Listen()
     Bind()
     Accept()

Anyway, if your question is about your code, it is fine. I don't know
Joe's code but I'm sure it works. :)

--