windows下C++的socket编程入门--文件传输

http://msdn.microsoft.com/en-us/library/windows/desktop/ms740632(v=vs.85).aspx

招着官方教程一步步做

主要函数或步骤：

WSAStartup, 初始化，WSACleanup，结束
socket(, ,) 构造函数，要有socket的instance才能实现传输
send()
recv()
listen(), server端开始要监听自己的端口号有没有被连接
bind()，server的用来listen（）的socket绑定address
accept()，如果没有client要连接，server在调用时就阻塞，有client要连接，就从这个要连接的队列里取出然后accept，然后server产生一个新的socket，而之前在listen（）的socket是和这个不一样的，微软为何要弄两个socket出来呢，网上有一些解释，似乎是为了使用时更清楚一点

全部代码再后面可以直接找到

运行：先运行server的exe，再运行client的exe

这样就学会了基本的C/S传输

然后再加入文件操作：在server打开一个文件，从文件里读入内容，一个个包传过去，一直读到文件结束；在client创建一个用来接收传输内容的文件，一个个包接收过来，接收过来的内容写在这个文件里。

以下是我用官网代码修改后的文件传输系统

/*server.cpp*/
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif

#include <Windows.h>
#include <WinSock2.h>
#include <WS2tcpip.h>
#include <IPHlpApi.h>
#include <cstdio>

#pragma comment (lib, "Ws2_32.lib")

#define DEFAULT_PORT "27015"
#define DEFAULT_BUFLEN 512

int main ()
{
int iResult, iSendResult;
WSADATA wsaData;
struct addrinfo *result = NULL, *ptr = NULL, hints;
char temp[DEFAULT_BUFLEN];

printf("input the file you want to transfer\n");
scanf("%s", temp);
//strcpy(temp, "input.txt");

// open file
FILE * fp = fopen(temp, "rb"); // binary mode for read
if(fp == NULL)
{
printf("open file %s failed\n", temp);
return -1;
}

if(WSAStartup(MAKEWORD(2, 2), &wsaData))
{
printf("server WSAStartup failed: %d\n", iResult);
return 1;
}

ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE; // caller to bind

// resolve the local address and port to be used by user
iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
if(iResult != 0)
{
printf("server getaddrinfo faild: %d\n", iResult);
WSACleanup();
return 1;
}

// create a socket for server
SOCKET ListenSocket = INVALID_SOCKET;
ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
if(ListenSocket == INVALID_SOCKET)
{
printf("server failed at socket(): %ld\n", WSAGetLastError());
freeaddrinfo(result);
WSACleanup();
return 1;
}

// bind a socket
iResult = bind(ListenSocket, result->ai_addr, (int)result->ai_addrlen);
if(iResult == SOCKET_ERROR)
{
printf("server bind faild: %ld\n", WSAGetLastError());
freeaddrinfo(result);
closesocket(ListenSocket);
WSACleanup();
return 1;
}
freeaddrinfo(result); // once bind, no longer needed

// listen on a socket
if(listen(ListenSocket, SOMAXCONN))
{
printf("server listen socket failed %ld\n", WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}

// accept a connection
sockaddr_in client_addr;
int nlen;
SOCKET ClientSocket = INVALID_SOCKET;
ClientSocket = accept(ListenSocket, NULL, NULL);
if(ClientSocket == INVALID_SOCKET)
{
printf("server accept failed: %ld\n",WSAGetLastError());
closesocket(ListenSocket);
WSACleanup();
return 1;
}
//char *ip = inet_ntoa(client_addr.sin_addr);
//printf("establish connection to server %s\n", ip);

// no longer need
closesocket(ListenSocket);

// file operation and send data

int num = 0;
while(!feof(fp))
{
num = fread(temp, 1, DEFAULT_BUFLEN, fp);
send(ClientSocket, temp, num, 0);
}
printf("server file transfer success\n");

fclose(fp);
iResult = shutdown(ClientSocket, SD_SEND);
if(iResult == SOCKET_ERROR)
{
printf("server shutdown failed %ld\n", WSAGetLastError());
closesocket(ClientSocket);
WSACleanup();
return 1;
}
closesocket(ClientSocket);
WSACleanup();

return 0;
}

/*client.cpp*/

//prevent winsock.h (version 1.1)from being included by windows.h
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#include <Windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <iphlpapi.h> // after winsock2.h
#include <cstdio>

#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")

#define DEFAULT_PORT "27015"
#define DEFAULT_BUFLEN 512

int main ()
{
int iResult;
WSADATA wsaData;
struct addrinfo *result = NULL, *ptr = NULL, hints;
char sendbuf[] = "this is a test for client";
char recvbuf[DEFAULT_BUFLEN];
int recvbuflen = DEFAULT_BUFLEN;
char temp[DEFAULT_BUFLEN], file_name[DEFAULT_BUFLEN];

printf("input ip address of server and file name\n");
scanf("%s%s", temp, file_name);

//create file
FILE *fp = fopen(file_name, "wb");
if(fp == NULL)
{
printf("create file %s failed\n", file_name);
return -1;
}

// initialize
if(WSAStartup(MAKEWORD(2,2), &wsaData))
{
printf("client WSAStartup failed: %d\n", iResult);
return 1;
}

ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;

// resolve the server address and port, argv[1] is server name
iResult = getaddrinfo(temp, DEFAULT_PORT, &hints, &result);
if(iResult != 0)
{
printf("client get addrinfor fail: %d\n", iResult);
WSACleanup(); // terminate use of WS2_32.dll
return 1;
}

SOCKET ConnectSocket = INVALID_SOCKET;
for(ptr = result; ptr != NULL; ptr = ptr->ai_next)
{
// create a socket for client
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
if(ConnectSocket == INVALID_SOCKET)
{
printf("client socket failed with error %ld\n", WSAGetLastError());
WSACleanup();
return 1;
}

// connect to server
iResult = connect(ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
if(iResult == SOCKET_ERROR)
{
closesocket(ConnectSocket);
ConnectSocket = INVALID_SOCKET;// if fail try next address returned by getaddrinfo
continue;
}
break;
}

freeaddrinfo(result);
if(ConnectSocket == INVALID_SOCKET)
{
printf("client unable to connect to server\n");
WSACleanup();
return 1;
}

//receive data from server
int num = 0;
while (1)
{
num = recv(ConnectSocket, temp, DEFAULT_BUFLEN, 0);
if(num == 0)
break;
fwrite(temp, 1, num, fp);
}
printf("transmission done\n");

fclose(fp);
closesocket(ConnectSocket);
WSACleanup();

return 0;
}

另：看到一个比较高端的，也可以参考下

http://blog.csdn.net/maopig/article/details/6801166?ADUIN=460174867&ADSESSION=1389244225&ADTAG=CLIENT.QQ.5275_.0&ADPUBNO=26274