33、Windows API 网络通信

* client.c
**************************************/
/* 头文件 */
#include < stdio.h >
#include " winsock2.h "
/* 常量 */
#define RECV_BUFFER_SIZE 8192
#pragma comment(lib,"ws2_32.lib")
/* ************************************
* main
* 功能 socket通信客户端
************************************* */
void main( int argc, char * argv[])
{
// 变量定义
SOCKADDR_IN clientService; // 地址
SOCKET ConnectSocket; // socket
WSADATA wsaData; // 库
LPVOID recvbuf; // 接收缓存
int bytesSent;
int bytesRecv = 0 ;
char sendbuf[ 32 ] = " get information " ; // 默认发送的数据

// 初始化socket库， 保存ws2_32.dll已经加载
int iResult = WSAStartup(MAKEWORD( 2 , 2 ), & wsaData);
if (iResult != NO_ERROR)
printf( " Error at WSAStartup()\n " );

// 创建socket
ConnectSocket = socket(AF_INET, // IPv4
SOCK_STREAM, // 顺序的、可靠的、基于连接的、双向的数据流通信
IPPROTO_TCP // 使用TCP协议
);
if (ConnectSocket == INVALID_SOCKET)
{
printf( " Error at socket(): %ld\n " , WSAGetLastError());
WSACleanup();
return ;
}

// 设置服务端的通信协议、IP地址、端口
clientService.sin_family = AF_INET;
clientService.sin_addr.s_addr = inet_addr( " 127.0.0.1 " );
clientService.sin_port = htons( 10000 );

// 连接到服务端
if ( connect(
ConnectSocket, // socket
(SOCKADDR * ) & clientService, // 地址
sizeof (clientService) // 地址的大小
) == SOCKET_ERROR)
{
printf( " Failed to connect(%d)\n " ,WSAGetLastError() );
WSACleanup();
return ;
}
// 准备发送数据
// 如果输入参数是-d，那么发送的数据是“download file”否则是"get information"
if (argc == 2 && ( ! lstrcmp(argv[ 1 ], " -d " )))
{
lstrcpyn(sendbuf, " download file " , 32 );
}
// 向服务端发送数据
bytesSent = send( ConnectSocket, // socket
sendbuf, // 发送的数据
lstrlen(sendbuf) + 1 , // 数据长度
0 ); // 无标志

if (bytesSent == SOCKET_ERROR)
{
printf( " send error (%d)\n " , WSAGetLastError());
closesocket(ConnectSocket);
return ;
}
printf( " Bytes Sent: %ld\n " , bytesSent );

// 准备接收数据
recvbuf = HeapAlloc(GetProcessHeap(), 0 , RECV_BUFFER_SIZE);
// 循环接收
while ( bytesRecv != SOCKET_ERROR )
{
// Sleep(50);
bytesRecv = recv( ConnectSocket, // socket
( char * )recvbuf, // 接收数据缓存
RECV_BUFFER_SIZE, // 缓存大小
0 ); // 无标志
if ( bytesRecv == 0 )
{
printf( " Connection Closed.\n " );
break ;
}
// TODO，处理接收的数据，这里只简单的将收到的数据大小显示
printf( " Bytes Recv: %ld\n " , bytesRecv );
}
HeapFree(GetProcessHeap(), 0 , recvbuf);
WSACleanup();
return ;
}


* server.c
**************************************/
/* 头文件 */
#include < winsock2.h >
#include < ws2tcpip.h >
#include < stdio.h >
/* 常量 */
#define DEFAULT_PORT "10000" // 端口
#define MAX_REQUEST 1024 // 接收数据的缓存大小
#define BUF_SIZE 4096 // 发送数据的缓存大小

#pragma comment(lib,"ws2_32.lib")
/* ************************************
* CommunicationThread
* 功能 用于接收和发送数据的线程
* 为每一个连接的客户端创建一个接收发送数据的线程，
* 可以使用多个客户端同时连接到服务端
* 参数 lpParameter，SOKCET
************************************* */
DWORD WINAPI CommunicationThread(
LPVOID lpParameter
)
{
DWORD dwTid = GetCurrentThreadId();
// 获得参数sokcet
SOCKET socket = (SOCKET)lpParameter;
// 为接收数据分配空间
LPSTR szRequest = (LPSTR)HeapAlloc(GetProcessHeap(), 0 , MAX_REQUEST);
int iResult;
int bytesSent; // 用于保存send的返回值，实际发送的数据的大小

// 接收数据
iResult = recv(socket, // socket
szRequest, // 接收缓存
MAX_REQUEST, // 缓存大小
0 ); // 标志
if (iResult == 0 ) // 接收数据失败，连接已经关闭
{
printf( " Connection closing...\n " );
HeapFree(GetProcessHeap(), 0 ,szRequest);
closesocket(socket);
return 1 ;
}
else if (iResult == SOCKET_ERROR) // 接收数据失败，socket错误
{
printf( " recv failed: %d\n " , WSAGetLastError());
HeapFree(GetProcessHeap(), 0 ,szRequest);
closesocket(socket);
return 1 ;
}
else if (iResult > 0 ) // 接收数据成功
{
// 显示接收到的数据
printf( " \tCommunicationThread(%d)\tBytes received: %d\n " , dwTid, iResult);
printf( " \tCommunicationThread(%d)\trequest string is (%s)\n " ,dwTid, szRequest);

// 如果接收到的数据是"download file"
if (lstrcmpi(szRequest, " download file " ) == 0 )
{
// 读取文件download.txt将发送
HANDLE hFile;
LPVOID lpReadBuf; // 发送缓存
DWORD dwBytesRead;
DWORD dwFileSize;
DWORD dwSendFile = 0 ;
hFile = CreateFile( " download.txt " ,
GENERIC_READ,
FILE_SHARE_READ,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);

if (hFile == INVALID_HANDLE_VALUE)
{
printf( " \tCommunicationThread\tCould not open file (error %d)\n " ,
GetLastError());
send(socket, " error " , 6 , 0 );
closesocket(socket);
return 1 ;
}
// 分配发送数据缓存
lpReadBuf = HeapAlloc(GetProcessHeap(), 0 , BUF_SIZE);
// 获取文件大小
dwFileSize = GetFileSize(hFile, NULL);
// 循环发送
while ( 1 )
{
// 读文件到缓存
if ( ! ReadFile(hFile, lpReadBuf, BUF_SIZE, & dwBytesRead, NULL))
{
printf( " \tCommunicationThread\tCould not read from file (error %d)\n " ,
GetLastError());
closesocket(socket);
CloseHandle(hFile);
return 1 ;
}
// 发送读取的文件数据
bytesSent = send(socket, ( const char * )lpReadBuf, dwBytesRead, 0 );
if ( bytesSent == SOCKET_ERROR)
{
printf( " \tCommunicationThread\tsend error %d\n " ,
WSAGetLastError());
closesocket(socket);
CloseHandle(hFile);
return 1 ;
}
// 显示发送数据的大小
printf( " \tCommunicationThread(%d)\tsend %d bytes\n " , dwTid, bytesSent);
// 累加，已经发送的大小
dwSendFile += dwBytesRead;
// 如果所有文件数据都已经发送
if (dwSendFile == dwFileSize)
{
printf( " \tCommunicationThread\tFile download ok\n " );
break ; // 退出循环
}
}
// 释放内存、关闭连接，关闭文件
HeapFree(GetProcessHeap(), 0 , lpReadBuf);
CloseHandle(hFile);
closesocket(socket);
}
// 如果接收到的数据是"get information"
else if (lstrcmpi(szRequest, " get information " ) == 0 )
{
// 发送数据
bytesSent = send(socket, // socket
" this is information " , // 数据
lstrlen( " this is information " ) + 1 , // 数据长度
0 ); // 标志
// 判断是否成功
if ( bytesSent == SOCKET_ERROR)
{
printf( " \tCommunicationThread\tsend error %d\n " ,
WSAGetLastError());
closesocket(socket);
return 1 ;
}
printf( " \tCommunicationThread(%d)\tsend %d bytes\n " ,dwTid, bytesSent);
}
else // 收到未知数据
{
printf ( " unreferenced request\n " );
}
}
// 释放接收数据缓存，关闭socket
HeapFree(GetProcessHeap(), 0 ,szRequest);
closesocket(socket);
return 0 ;
}

/* ************************************
* int __cdecl main(void)
* 功能 socket服务端
************************************* */
int __cdecl main( void )
{
WSADATA wsaData;
SOCKET ListenSocket = INVALID_SOCKET; // 监听socket
SOCKET ClientSocket = INVALID_SOCKET; // 连接socket
struct addrinfo * result = NULL,
hints;
int iResult; // 保存返回结果

// 初始化Winsock，保证Ws2_32.dll已经加载
iResult = WSAStartup(MAKEWORD( 2 , 2 ), & wsaData);
if (iResult != 0 )
{
printf( " WSAStartup failed: %d\n " , iResult);
return 1 ;
}
// 地址
ZeroMemory( & hints, sizeof (hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;

// 获取主机地址，保证网络协议可用等
iResult = getaddrinfo(NULL, // 本机
DEFAULT_PORT, // 端口
& hints, // 使用的网络协议，连接类型等
& result); // 结果
if ( iResult != 0 )
{
printf( " getaddrinfo failed: %d\n " , iResult);
WSACleanup();
return 1 ;
}

// 创建socket，用于监听
ListenSocket = socket(
result -> ai_family, // 网络协议，AF_INET，IPv4
result -> ai_socktype, // 类型，SOCK_STREAM
result -> ai_protocol); // 通信协议，TCP
if (ListenSocket == INVALID_SOCKET)
{
printf( " socket failed: %ld\n " , WSAGetLastError());
freeaddrinfo(result);
WSACleanup();
return 1 ;
}
// 绑定到端口
iResult = bind( ListenSocket, result -> ai_addr, ( int )result -> ai_addrlen);
if (iResult == SOCKET_ERROR)
{
printf( " bind failed: %d\n " , WSAGetLastError());
freeaddrinfo(result);
closesocket(ListenSocket);
WSACleanup();
return 1 ;
}
printf( " bind\n " );

freeaddrinfo(result); // reuslt不再使用

// 开始监听
iResult = listen(ListenSocket, SOMAXCONN);
printf( " start listen......\n " );
if (iResult == SOCKET_ERROR)
{
printf( " listen failed: %d\n " , WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1 ;
}
while ( 1 )
{
// 接收客户端的连接，accept函数会等待，直到连接建立
printf( " ready to accept\n " );
ClientSocket = accept(ListenSocket, NULL, NULL);
// accept函数返回，说明已经有客户端连接
// 返回连接socket
printf( " accept a connetion\n " );
if (ClientSocket == INVALID_SOCKET)
{
printf( " accept failed: %d\n " , WSAGetLastError());
closesocket(ListenSocket);
break ; // 等待连接错误，退出循环
}
// 为每一个连接创建一个数据发送的接收线程，
// 使服务端又可以立即接收其他客户端的连接
if ( ! CreateThread(
NULL,
0 ,
CommunicationThread, // 线程函数
(LPVOID)ClientSocket, // 将socket作为参数
0 ,
NULL))
{
printf( " Create Thread error (%d) " , GetLastError());
break ;
}
}
// 循环退出，释放DLL。
WSACleanup();
return 0 ;
}