VC: Developing applications using Windows Sockets

Socket programming based on TCP (connection-oriented)

First, the client:

1. Open a socket (socket);

2, initiate connection request (connect);

3, if the connection is successful, then the data exchange (read, write, send, recv);

4, the data exchange is complete, close the connection (shutdown, close);

Second, server-side:

1. Open a socket (socket);

2. Bind the socket to the server address (BIND);

3, the designated socket is the server socket (listen), to prepare the connection request;

4, Waiting for connection request (connect);

5, if the connection request to, then the connection establishes, carries on the data exchange (read, write, send, recv);

6, the data exchange is complete, close the connection (shutdown, close);

UDP-based socket programming for non-connected

One, client \ server side:

1. Open a socket (socket);

2. Bind the socket to the specified server address and port (BIND);

3, the exchange of data (read, write, send, recv);

4, the data exchange is complete, close the connection (shutdown, close);

Third, MFC's support for sockets:

1, create CAsyncSocket object;

2. Send and receive Data report (SendTo, recvfrom);

3, connect the server (connect);

4, receive connection (Listen);

5, send and receive streaming data (send, receive);

6. Close the socket (close);

7, Error treatment (GetLastError).

Iv. Examples: web chat Tools

Client:

1 、。。。。

2. Use the Class Wizard to overload the CAsyncSocket class to generate a new Mysocket class.

3. Use the Class Wizard to overload CAsyncSocket's onreceive (int nerrorcode) and onsend (int nerrorcode), OnConnect (int nerrorcode) functions.

void mysocket::onreceive (int nerrorcode)

{

Todo:add your specialized code here and/or call the base class

Get the dialog pointer

ctestapp*papp= (ctestapp*) AfxGetApp ();

ctestdlg*pdlg= (ctestdlg*) papp->m_pmainwnd;

Insert a message into the edit box

Char *pbuf=new char[4096];

int ibufsize=4096;

int IRCVD;

CString STRRECVD;

Ircvd=receive (pbuf,ibufsize);

if (ircvd==socket_error)

{

Pdlg->messagebox ("Socket_error");

}

Else

{

Pbuf[ircvd]=null;

pdlg->m_recmsg+= "Server:";

pdlg->m_recmsg+=pbuf;

pdlg->m_recmsg+= "\ r \ n";

Pdlg->refreshscreen ();

}

Delete pbuf;

Casyncsocket::onreceive (Nerrorcode);

}

void mysocket::onsend (int nerrorcode)

{

Todo:add your specialized code here and/or call the base class

Casyncsocket::onsend (Nerrorcode);

}

void Mysocket::onconnect (int nerrorcode)

{

Todo:add your specialized code here and/or call the base class

ctestapp*papp= (ctestapp*) AfxGetApp ();

ctestdlg*pdlg= (ctestdlg*) papp->m_pmainwnd;

int Iresult=nerrorcode;

CString buffer;

int Namelen;

if (iresult!=0)

{

Buffer. Format ("Connection server failed. \ r \ n ");

pdlg->m_recmsg+=buffer;

}

Else

{

Namelen=sizeof (sockaddr_in);

Buffer. Format ("Successfully connected to server%s:%d.\r\n", pdlg->m_ipstr,pdlg->m_port);

pdlg->m_recmsg+=buffer;

Pdlg->getdlgitem (idc_send)->enablewindow (TRUE);

Pdlg->getdlgitem (IDOK)->enablewindow (TRUE);

}

Pdlg->refreshscreen ();

Casyncsocket::onconnect (Nerrorcode);

}

4, in the C*dlg class

In the header file:

#include "MySocket.h"

Mysocket M_socket;

CString M_ipstr;

. CPP file:

void Ctestdlg::onsend ()

{

Todo:add your control notification handler code here

int Ilen;

int isent;

UpdateData (TRUE);

if (m_msg!= "")

{

Ilen=m_msg. GetLength ();

Isent=m_socket. Send (LPCTSTR (m_msg), Ilen);

if (isent==socket_error)

{

MessageBox ("Connection failed, please try again!") ");

Connect=false;

}

Else

{

m_recmsg+= "client:" +M_MSG;

m_recmsg+= "\ r \ n";

UpdateData (FALSE);

}

}

}

void Ctestdlg::refreshscreen ()

{

UpdateData (FALSE);

}

void Ctestdlg::onconnect ()

{

if (! AfxSocketInit ())

{

AfxMessageBox ("idp_sockets_init_failed");

return;

}

GetDlgItemText (IDC_IPADDRESS1,M_IPSTR);

M_socket.m_hsocket=invalid_socket;

UpdateData (TRUE);

BOOL Flag=m_socket. Create ();

if (!flag)

{

AfxMessageBox ("SOCKET ERROR");

Return

}

M_socket. Connect (M_ipstr,m_port);

}

void Ctestdlg::onok ()

{

Todo:add Extra Validation here

M_socket. Close ();

Cdialog::onok ();

}

Server-side:

1 、。。。。

2. Use the Class Wizard to overload the CAsyncSocket class to generate a new Mysocket class.

3. Use the Class Wizard to reload CAsyncSocket onreceive (int nerrorcode) and onsend (int nerrorcode) functions.

void mysocket::onreceive (int nerrorcode)

{

Todo:add your specialized code here and/or call the base class

ctestapp*papp= (ctestapp*) AfxGetApp ();

ctestdlg*pdlg= (ctestdlg*) papp->m_pmainwnd;

Insert a message into the list box

Char *pbuf=new char[4096];

int ibufsize=4096;

int IRCVD;

CString STRRECVD;

Ircvd=receive (pbuf,ibufsize);

if (ircvd==socket_error)

{

Pdlg->messagebox ("Socket_error");

}

Else

{

Pbuf[ircvd]=null;

pdlg->m_msg+= "Client:";

pdlg->m_msg+=pbuf;

pdlg->m_msg+= "\ r \ n";

Pdlg->refreshscreen ();

}

Delete pbuf;

Casyncsocket::onreceive (Nerrorcode);

}

void mysocket::onsend (int nerrorcode)

{

Todo:add your specialized code here and/or call the base class

Casyncsocket::onsend (Nerrorcode);

}

4. Create a new myServerSocket class and add Mysocket * m_socket, which is the socket pointer after receiving the request.

Mysocket * M_socket;

void cmyserversocket::onaccept (int nerrorcode)

{

Todo:add your specialized code here and/or call the base class

ctestapp*papp= (ctestapp*) AfxGetApp ();

ctestdlg*pdlg= (ctestdlg*) papp->m_pmainwnd;

Show connection messages

pdlg->m_msg= "Client connection to Server";

pdlg->m_msg+= "\ r \ n";

Pdlg->refreshscreen ();

Pdlg->getdlgitem (idc_send)->enablewindow (TRUE);

Pdlg->getdlgitem (IDOK)->enablewindow (TRUE);

mysocket* psocket=new mysocket ();

if (Accept (*psocket))

{

Psocket->asyncselect (Fd_read);

M_socket=psocket;

}

Else

{

Delete Psocket;

}

Casyncsocket::onaccept (Nerrorcode);

}

5, the C*dlg class

void Ctestdlg::refreshscreen ()

{

UpdateData (FALSE);

}

void Ctestdlg::onlisten ()//Create server

{

Todo:add your control notification handler code here

UpdateData (TRUE);

if (! AfxSocketInit ())

{

AfxMessageBox ("idp_sockets_init_failed");

return;

}

BOOL Flag=m_serversocket. Create (M_port);

if (!flag)

{

AfxMessageBox ("SOCKET ERROR");

Return

}

Flag=m_serversocket. Listen (1);

if (!flag)

{

AfxMessageBox ("SOCKET ERROR");

Return

}

Setdlgitemtext (Idc_listen, "listening");

}

void Ctestdlg::onsend ()

{

Todo:add your control notification handler code here

int Ilen;

int isent;

UpdateData (TRUE);

if (m_sendmsg!= "")

{

Ilen=m_sendmsg. GetLength ();

Isent=m_serversocket.m_socket->send (LPCTSTR (m_sendmsg), Ilen);

if (isent==socket_error)

{

MessageBox ("Connection failed, please try again!") ");

}

Else

{

m_msg+= "server:" +M_SENDMSG;

m_msg+= "\ r \ n";

UpdateData (FALSE);

}

}

}

void Ctestdlg::onok ()

{

Todo:add Extra Validation here

m_sendmsg= "Server Exit";

UpdateData (FALSE);

OnSend ();

M_serversocket. Close ();

Cdialog::onok ();

}

VC: Developing applications using Windows Sockets