9930.txt

关于编程技术技巧的文章

int CloseServer()  //关闭服务
{
	closesocket(gListen_Socket);
	WSACleanup();
	return 1;
}

//分析接收到的字符，得到远程主机地址
int GetAddressAndPort( char * str, char *address, int * port)
{
	char buf[BUFSIZE], command[512], proto[128], *p;
	int j;
	sscanf(str,"%s%s%s",command,buf,proto);
	p=strstr(buf,HTTP);
	//HTTP
	if(p)
	{
		p+=strlen(HTTP);
		for(int i=0;i< strlen(p);i++)
			if( *(p+i)=='/') break;
		*(p+i)=0;
		strcpy(address,p);
		p=strstr(str,HTTP);
		for(int j=0;j< i+strlen(HTTP);j++)
			*(p+j)=' '; //去掉远程主机名: GET http://www.njust.edu.cn/ 
HTTP1.1  == > GET / HTTP1.1
		*port=80;      //缺省的 http 端口 
	}
	else
	{//FTP, 不支持, 下面的代码可以省略.
	 p=strstr(buf,FTP);
	 if(!p) return 0;
	 	p+=strlen(FTP);
		for(int i=0;i< strlen(p);i++)
			if( *(p+i)=='/') break;      //Get The Remote Host
		*(p+i)=0;
		for(j=0;j< strlen(p);j++)
			if(*(p+j)==':') 
				{*port=atoi(p+j+1);    //Get The Port
			     *(p+j)=0;
				}
			 else *port=21;		 			              

		strcpy(address,p);
		p=strstr(str,FTP);
		for(j=0;j< i+strlen(FTP);j++)
			*(p+j)=' ';		
	}
	return 1; 
}

// 取到本地的数据，发往远程主机
UINT UserToProxyThread(void *pParam)
{
	 char Buffer[BUFSIZE];
	 int  Len;
	 sockaddr_in from;
	 SOCKET msg_socket;
	 int fromlen,retval;
	 SocketPair SPair;
	 ProxyParam ProxyP;
	 CWinThread *pChildThread;
     fromlen=sizeof(from);
	 msg_socket=accept(gListen_Socket,(struct sockaddr*)&from,&fromlen);
 	 AfxBeginThread(UserToProxyThread,pParam); //启动另一侦听.
	 if( msg_socket==INVALID_SOCKET)
		{ printf( "\nError  in accept "); return -5;}
	 
	//读客户的第一行数据

	 SPair.IsUser_ProxyClosed=FALSE;
	 SPair.IsProxy_ServerClosed=TRUE;
	 SPair.user_proxy=msg_socket;

	 retval=recv(SPair.user_proxy,Buffer,sizeof(Buffer),0);
	 
	 if(retval==SOCKET_ERROR)
			{ printf("\nError Recv"); 
		      if(SPair.IsUser_ProxyClosed==FALSE)
				{closesocket(SPair.user_proxy);
				 SPair.IsUser_ProxyClosed=TRUE;
				}
			}
	 if(retval==0)
			{printf("Client Close connection\n");
		     if(SPair.IsUser_ProxyClosed==FALSE)
				{closesocket(SPair.user_proxy);
				 SPair.IsUser_ProxyClosed=TRUE;
				}
			}
	 Len=retval;
#ifdef _DEBUG

	 Buffer[Len]=0;
	 printf("\n Received %d bytes,data[%s]from client\n",retval,Buffer);
#endif
	 //
	 SPair.IsUser_ProxyClosed=FALSE;
	 SPair.IsProxy_ServerClosed=TRUE;
	 SPair.user_proxy=msg_socket;

	 ProxyP.pPair=&SPair;
	 ProxyP.User_SvrOK=CreateEvent(NULL,TRUE,FALSE,NULL);
	 
	 GetAddressAndPort( Buffer,ProxyP.Address,&ProxyP.Port);

	 pChildThread=AfxBeginThread(ProxyToServer,(LPVOID)&ProxyP);
	 ::WaitForSingleObject(ProxyP.User_SvrOK,60000);  //等待联结
	 ::CloseHandle(ProxyP.User_SvrOK);

  while(SPair.IsProxy_ServerClosed ==FALSE && SPair.IsUser_ProxyClosed==FALSE)
	 {	
	   retval=send(SPair.proxy_server,Buffer,Len,0);
	   if(retval==SOCKET_ERROR)
		{ printf("\n send() failed:error%d\n",WSAGetLastError());
	     if(SPair.IsProxy_ServerClosed==FALSE)
			{
				closesocket(SPair.proxy_server);
				SPair.IsProxy_ServerClosed=TRUE;
			}
		  continue;
		}
	    retval=recv(SPair.user_proxy,Buffer,sizeof(Buffer),0);
	 
		if(retval==SOCKET_ERROR)
			{ printf("\nError Recv"); 
		      if(SPair.IsUser_ProxyClosed==FALSE)
				{closesocket(SPair.user_proxy);
				 SPair.IsUser_ProxyClosed=TRUE;
				}
		      continue;
			}
		if(retval==0)
			{printf("Client Close connection\n");
		     if(SPair.IsUser_ProxyClosed==FALSE)
				{closesocket(SPair.user_proxy);
				 SPair.IsUser_ProxyClosed=TRUE;
				}
			 break;
			}
		Len=retval;
#ifdef _DEBUG
		Buffer[Len]=0;
	 printf("\n Received %d bytes,data[%s]from client\n",retval,Buffer);
#endif
	
  } //End While

     if(SPair.IsProxy_ServerClosed==FALSE)
			{
				closesocket(SPair.proxy_server);
				SPair.IsProxy_ServerClosed=TRUE;
			}
	 if(SPair.IsUser_ProxyClosed==FALSE)
				{closesocket(SPair.user_proxy);
				 SPair.IsUser_ProxyClosed=TRUE;
				}
	::WaitForSingleObject(pChildThread- >m_hThread,20000);  //Should check the 
return value
	return 0;
}

// 读取远程主机数据，并发往本地客户机
UINT ProxyToServer(LPVOID pParam){
    ProxyParam * pPar=(ProxyParam*)pParam;
	char Buffer[BUFSIZE];
	char *server_name= "localhost";
	unsigned short port ;
	int retval,Len;
	unsigned int addr;
	int socket_type ;
	struct sockaddr_in server;
	struct hostent *hp;
	SOCKET  conn_socket;

	socket_type = SOCK_STREAM;
	server_name = pPar- >Address;
	port = pPar- >Port;

	if (isalpha(server_name[0])) {   /* server address is a name */
		hp = gethostbyname(server_name);
	}
	else  { /* Convert nnn.nnn address to a usable one */
		addr = inet_addr(server_name);
		hp = gethostbyaddr((char *)&addr,4,AF_INET);
	}
	if (hp == NULL ) {
		fprintf(stderr,"Client: Cannot resolve address [%s]: Error %d\n",
			server_name,WSAGetLastError());
		::SetEvent(pPar- >User_SvrOK);	
		return 0;
	}

	//
	// Copy the resolved information into the sockaddr_in structure
	//
	memset(&server,0,sizeof(server));
	memcpy(&(server.sin_addr),hp- >h_addr,hp- >h_length);
	server.sin_family = hp- >h_addrtype;
	server.sin_port = htons(port);

	conn_socket = socket(AF_INET,socket_type,0); /* 打开一个 socket */
	if (conn_socket < 0 ) {
		fprintf(stderr,"Client: Error Opening socket: Error %d\n",
			WSAGetLastError());
		pPar- >pPair- >IsProxy_ServerClosed=TRUE;
		::SetEvent(pPar- >User_SvrOK);	
		return -1;
	}


#ifdef _DEBUG
	printf("Client connecting to: %s\n",hp- >h_name);
#endif
	if (connect(conn_socket,(struct sockaddr*)&server,sizeof(server))
		== SOCKET_ERROR) {
		fprintf(stderr,"connect() failed: %d\n",WSAGetLastError());
		pPar- >pPair- >IsProxy_ServerClosed=TRUE;	
		::SetEvent(pPar- >User_SvrOK);	
		return -1;
	}
	pPar- >pPair- >proxy_server=conn_socket;
	pPar- >pPair- >IsProxy_ServerClosed=FALSE;
    ::SetEvent(pPar- >User_SvrOK);
	// cook up a string to send
	while(!pPar- >pPair- >IsProxy_ServerClosed &&!pPar- >pPair->IsUser_ProxyClosed)
	{
		retval = recv(conn_socket,Buffer,sizeof (Buffer),0 );
		if (retval == SOCKET_ERROR ) {
			fprintf(stderr,"recv() failed: error %d\n",WSAGetLastError());
			closesocket(conn_socket);
			pPar- >pPair- >IsProxy_ServerClosed=TRUE;
			break;
		}
		Len=retval;
		if (retval == 0) {
			printf("Server closed connection\n");
			closesocket(conn_socket);
			pPar- >pPair- >IsProxy_ServerClosed=TRUE;
			break;
			}

		retval = send(pPar- >pPair- >user_proxy,Buffer,Len,0);
		if (retval == SOCKET_ERROR) {
			fprintf(stderr,"send() failed: error %d\n",WSAGetLastError());
			closesocket(pPar- >pPair- >user_proxy);
			pPar- >pPair- >IsUser_ProxyClosed=TRUE;
			break;						
		}
#ifdef _DEBUG	
		Buffer[Len]=0;		
		printf("Received %d bytes, data [%s] from server\n",retval,Buffer);
#endif
	}
	if(pPar- >pPair- >IsProxy_ServerClosed==FALSE)
			{
				closesocket(pPar- >pPair- >proxy_server);
				pPar- >pPair- >IsProxy_ServerClosed=TRUE;
			}
	 if(pPar- >pPair- >IsUser_ProxyClosed==FALSE)
				{closesocket(pPar- >pPair- >user_proxy);
				 pPar- >pPair- >IsUser_ProxyClosed=TRUE;
				}
	 return 1;
}



int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
	int nRetCode = 0;

	// 初始化SOCKET
	if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))
	{
		// 错误处理
		cerr < <  _T("Fatal Error: MFC initialization failed") < <  endl;
		nRetCode = 1;
	}
	else
	{
		// 主程序开始.
		StartServer();	
		while(1)	
			if(getchar()=='q') break;
		CloseServer();
	}

	return nRetCode;
}

****************************************************************

                   提高FoxPro应用程序的智商  

                         作者: 曹祖权 

　　你是否有这样的感受：编好一个应用程序之后，分发时还得带上一大
堆DBF、IDX、MEM文件，十分麻烦。而且这些文件还很娇气，如果用户误
删了其中一个，程序马上罢工。我这里告诉大家一个办法，就是提高FoxPro
应用程序的IQ值，让它自己检测工作目录中是否存在所需要的DBF、IDX等
文件，若有就可万事大吉，顺利工作；若没有则利用FoxPro仅能支持的几
条SQL语句(CREATE TABLE、INSERT INTO)，自动创建数据库、添加数据和
建立索引。这样，你的应用程序分发时就可以精简到一个EXE文件，因为
这个EXE文件在第一次运行时，会自动帮助你建立所需的数据库、索引和
添加数据库记录。而且，当用户误删了这些文件时，应用程序也会重建它
们，不会导致程序不能运行。当然，有些数据还须重新输入。
　　
　　本文以一个文书档案管理系统为例加以说明：这个系统需要三个数
据库文件：卷内文件目录库jlwjml.dbf(按案卷号＋顺序号建立索引)、
单位库dwk.dbf、保管期限库bgqxk.dbf(含有永久、长期、短期三条记录)，
在主程序的初始化部分加入如下程序即可：

　　CLOSE DATABASE 
　　IF !FILE('jlwjml.dbf') 
　　CREATE TABLE jlwjml ; 
　　(案卷号N(4),顺序号N(3),文号C(30),; 
　　责任者C(20),题名C(90),日期D,保管期限C(4),页号N(3),备注C(20)) 
　　INDEX ON str(案卷号,4)＋str(顺序号,3) to jlwjmlsy 
　　ENDIF 
　　IF !FILE('jlwjmlsy.idx') 
　　INDEX ON str(案卷号,4)＋str(顺序号,3) to jlwjmlsy 
　　ENDIF 
　　IF !FILE('dwk.dbf') 
　　CREATE TABLE dwk (单位名C(30)) 
　　ENDIF 
　　IF !FILE('bgqxk.dbf') 
　　CREATE TABLE bgqxk (保管期限C(4))