02/02 - tcp/ip network programming - client src

void CTCPEchoClientDlg::OnButtonConnectServer()
{
 // TODO: Add your control notification handler code here
 //create socket and connect
 CString tmp = _T("");

 //create socket
 g_hSocket = ::socket(PF_INET,SOCK_STREAM,0);

 if( g_hSocket == INVALID_SOCKET){
  tmp.Format(_T("Fail to create socket"),::WSAGetLastError());
  AfxMessageBox(tmp);
  return;
 }

 //create socket information (bind)
 SOCKADDR_IN SockAddr;
 ::ZeroMemory(&SockAddr,sizeof(SockAddr));

 SockAddr.sin_family    = AF_INET;
 SockAddr.sin_addr.S_un.S_addr = inet_addr(U_HOSTADDR);
 SockAddr.sin_port    = ::htons(U_CONNPORT);

 //connect to server
 if(::connect(g_hSocket,(SOCKADDR*)&SockAddr, sizeof(SOCKADDR_IN))!=0){
  tmp.Format(_T("Fail to connect server. [Error Code: %d]"),::WSAGetLastError());
  AfxMessageBox(tmp);

  ::closesocket(g_hSocket);
  g_hSocket = NULL;
  return;
 }

 AfxMessageBox(_T("Connect Server."));

 SetDlgItemText(IDC_StaticStatus,_T("Connected"));

 GetDlgItem(IDC_Button_ConnectServer)->EnableWindow(FALSE);
 GetDlgItem(IDC_ButtonSend)->EnableWindow(TRUE);
 GetDlgItem(IDC_ButtonDisconnect)->EnableWindow(TRUE);
 
}

void CTCPEchoClientDlg::OnButtonSend()
{
 // TODO: Add your control notification handler code here
 //send
 if(g_hSocket == NULL){
  AfxMessageBox(_T("Not Connected Server."));
  return;
 }

 CString tmp = _T("");
 char szBufferSend[U_BUFSIZE], szBufferRecv[U_BUFSIZE];
 ::ZeroMemory(szBufferSend,U_BUFSIZE);
 ::ZeroMemory(szBufferRecv,U_BUFSIZE);

 sprintf(szBufferSend, _T("%s"), _T("Test String"));
 int nLength = lstrlen(szBufferSend);

 //sending string
 if(nLength != ::send(g_hSocket,szBufferSend, nLength, 0)){
  tmp.Format(_T("Fail to sending test string. [Error Code: %d]"),::WSAGetLastError());
  AfxMessageBox(tmp);

  return;
 }

 //print recieve test message from server
 ::recv(g_hSocket, szBufferRecv, U_BUFSIZE, 0);
 AfxMessageBox(szBufferRecv);
}

void CTCPEchoClientDlg::OnButtonDisconnect()
{
 // TODO: Add your control notification handler code here
 // disconnect and close socket
 if( g_hSocket == NULL){
  AfxMessageBox(_T("not connected server."));
  return;
 }

 GetDlgItem(IDC_Button_ConnectServer)->EnableWindow(TRUE);
 GetDlgItem(IDC_ButtonSend)->EnableWindow(FALSE);
 GetDlgItem(IDC_ButtonDisconnect)->EnableWindow(FALSE);

 ::shutdown(g_hSocket,SD_BOTH);
 ::closesocket(g_hSocket);

 SetDlgItemText(IDC_StaticStatus,_T("Disconnected"));
 AfxMessageBox(_T("Terminate connection on server."));
 g_hSocket = NULL;
}