C++利用SOCKET传送文件

 

C++利用SOCKET传送文件

 

/*server.h*/

#pragma comment(lib, "WS2_32")

#include <WinSock2.h>
#include <iostream>
//#include <stdio.h>
#include <assert.h>

#ifndef COMMONDEF_H
#define COMMONDEF_H

#define MAX_PACKET_SIZE   10240    // 数据包的最大长度,单位是sizeof(char)
#define MAXFILEDIRLENGTH 256     // 存放文件路径的最大长度
#define PORT     4096    // 端口号
#define SERVER_IP    "127.0.0.1" // server端的IP地址

// 各种消息的宏定义
#define INVALID_MSG      -1   // 无效的消息标识
#define MSG_FILENAME     1   // 文件的名称
#define MSG_FILELENGTH     2   // 传送文件的长度
#define MSG_CLIENT_READY    3   // 客户端准备接收文件
#define MSG_FILE      4   // 传送文件
#define MSG_SENDFILESUCCESS    5   // 传送文件成功
#define MSG_OPENFILE_ERROR    10   // 打开文件失败,可能是文件路径错误找不到文件等原因
#define MSG_FILEALREADYEXIT_ERROR 11   // 要保存的文件已经存在了

class CCSDef
{
public:
#pragma pack(1)      // 使结构体的数据按照1字节来对齐,省空间

// 消息头
struct TMSG_HEADER
{
   char    cMsgID;    // 消息标识

   TMSG_HEADER(char MsgID = INVALID_MSG)
    : cMsgID(MsgID)
   {
   }
};

// 请求传送的文件名
// 客户端传给服务器端的是全路径名称
// 服务器传回给客户端的是文件名
struct TMSG_FILENAME : public TMSG_HEADER
{
   char szFileName[256];   // 保存文件名的字符数组

   TMSG_FILENAME()
    : TMSG_HEADER(MSG_FILENAME)
   {
   }
};

// 传送文件长度
struct TMSG_FILELENGTH : public TMSG_HEADER
{
   long lLength;

   TMSG_FILELENGTH(long length)
    : TMSG_HEADER(MSG_FILELENGTH), lLength(length)
   {

   }
};

// Client端已经准备好了,要求Server端开始传送文件
struct TMSG_CLIENT_READY : public TMSG_HEADER
{
   TMSG_CLIENT_READY()
    : TMSG_HEADER(MSG_CLIENT_READY)
   {
   }
};

// 传送文件
struct TMSG_FILE : public TMSG_HEADER
{
   union     // 采用union保证了数据包的大小不大于MAX_PACKET_SIZE * sizeof(char)
   {
    char szBuff[MAX_PACKET_SIZE];
    struct
    {
     int nStart;
     int nSize;
     char szBuff[MAX_PACKET_SIZE - 2 * sizeof(int)];
    }tFile;
   };

   TMSG_FILE()
    : TMSG_HEADER(MSG_FILE)
   {

   }
};

// 传送文件成功
struct TMSG_SENDFILESUCCESS : public TMSG_HEADER
{
   TMSG_SENDFILESUCCESS()
    : TMSG_HEADER(MSG_SENDFILESUCCESS)
   {
   }
};

// 传送出错信息,包括:
// MSG_OPENFILE_ERROR:打开文件失败
// MSG_FILEALREADYEXIT_ERROR:要保存的文件已经存在了
struct TMSG_ERROR_MSG : public TMSG_HEADER
{
   TMSG_ERROR_MSG(char cErrorMsg)
    : TMSG_HEADER(cErrorMsg)
   {
   }
};

#pragma pack()
};

#endif

/*server.cpp*/

#include "server.h"

char g_szNewFileName[MAXFILEDIRLENGTH];
char g_szBuff[MAX_PACKET_SIZE + 1];
long g_lLength;
char* g_pBuff = NULL;

// 初始化socket库
bool InitSocket();
// 关闭socket库
bool CloseSocket();
// 解析消息进行相应的处理
bool ProcessMsg(SOCKET sClient);
// 监听Client的消息
void ListenToClient();
// 打开文件
bool OpenFile(CCSDef::TMSG_HEADER* pMsgHeader, SOCKET sClient);
// 传送文件
bool SendFile(SOCKET sClient);
// 读取文件进入缓冲区
bool ReadFile(SOCKET sClient);

int main()
{
InitSocket();
ListenToClient();
CloseSocket();

return 0;
}

void ListenToClient()
{
// 创建socket套接字
SOCKET sListen = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (SOCKET_ERROR == sListen)
{
   printf("Init Socket Error!\n");
   return;
}

// 绑定socket到一个本地地址
sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = htons(PORT);
sin.sin_addr.S_un.S_addr = INADDR_ANY;
if (::bind(sListen, (LPSOCKADDR)&sin, sizeof(sockaddr_in)) == SOCKET_ERROR)
{
   printf("Bind Error!\n");
   return;
}

// 设置socket进入监听状态
if (::listen(sListen, 10) == SOCKET_ERROR)
{
   printf("Listen Error!\n");
   return;
}

printf("Listening To Client...\n");

// 循环接收client端的连接请求
sockaddr_in ClientAddr;
int nAddrLen = sizeof(sockaddr_in);
SOCKET sClient;

while (INVALID_SOCKET == (sClient = ::accept(sListen, (sockaddr*)&ClientAddr, &nAddrLen)))
{
}

while (true == ProcessMsg(sClient))
{
}

// 关闭同客户端的连接
::closesocket(sClient);

::closesocket(sListen);
}

bool InitSocket()
{
// 初始化socket dll
WSADATA wsaData;
WORD socketVersion = MAKEWORD(2, 2);
if (::WSAStartup(socketVersion, &wsaData) != 0)
{
   printf("Init socket dll error\n");
   return false;
}

return true;
}

bool CloseSocket()
{
// 释放winsock库
::WSACleanup();

if (NULL != g_pBuff)
{
   delete [] g_pBuff;
   g_pBuff = NULL;
}

return true;
}

bool ProcessMsg(SOCKET sClient)
{
int nRecv = ::recv(sClient, g_szBuff, MAX_PACKET_SIZE + 1, 0);
if (nRecv > 0)
{
   g_szBuff[nRecv] = '\0';
}

// 解析命令
CCSDef::TMSG_HEADER* pMsgHeader = (CCSDef::TMSG_HEADER*)g_szBuff;
switch (pMsgHeader->cMsgID)
{
case MSG_FILENAME:    // 文件名
   {
    OpenFile(pMsgHeader, sClient);
   }
   break;
case MSG_CLIENT_READY:   // 客户端准备好了,开始传送文件
   {
    SendFile(sClient);
   }
   break;
case MSG_SENDFILESUCCESS: // 传送文件成功
   {
    printf("Send File Success!\n");
    return false;
   }
   break;
case MSG_FILEALREADYEXIT_ERROR: // 要保存的文件已经存在了
   {
    printf("The file reay to send already exit!\n");
    return false;
   }
   break;
}

return true;
}

bool ReadFile(SOCKET sClient)
{
if (NULL != g_pBuff)
{
   return true;
}

// 打开文件
FILE *pFile;
if (NULL == (pFile = fopen(g_szNewFileName, "rb")))   // 打开文件失败
{
   printf("Cannot find the file, request the client input file name again\n");
   CCSDef::TMSG_ERROR_MSG tMsgErrorMsg(MSG_OPENFILE_ERROR);
   ::send(sClient, (char*)(&tMsgErrorMsg), sizeof(CCSDef::TMSG_ERROR_MSG), 0);
   return false;
}

// 把文件的长度传回到client去
fseek(pFile, 0, SEEK_END);
g_lLength = ftell(pFile);
printf("File Length = %d\n", g_lLength);
CCSDef::TMSG_FILELENGTH tMsgFileLength(g_lLength);
::send(sClient, (char*)(&tMsgFileLength), sizeof(CCSDef::TMSG_FILELENGTH), 0);

// 处理文件全路径名,把文件名分解出来
char szDrive[_MAX_DRIVE], szDir[_MAX_DIR], szFname[_MAX_FNAME], szExt[_MAX_EXT];
_splitpath(g_szNewFileName, szDrive, szDir, szFname, szExt);
strcat(szFname,szExt);
CCSDef::TMSG_FILENAME tMsgFileName;
strcpy(tMsgFileName.szFileName, szFname);
printf("Send File Name: %s\n", tMsgFileName.szFileName);
::send(sClient, (char*)(&tMsgFileName), sizeof(CCSDef::TMSG_FILENAME), 0);

// 分配缓冲区读取文件内容
g_pBuff = new char[g_lLength + 1];
if (NULL == g_pBuff)
{
   return false;
}

fseek(pFile, 0, SEEK_SET);
fread(g_pBuff, sizeof(char), g_lLength, pFile);
g_pBuff[g_lLength] = '\0';
fclose(pFile);

return true;
}

// 打开文件
bool OpenFile(CCSDef::TMSG_HEADER* pMsgHeader, SOCKET sClient)
{
CCSDef::TMSG_FILENAME* pRequestFilenameMsg = (CCSDef::TMSG_FILENAME*)pMsgHeader;

// 对文件路径名进行一些处理
char *p1, *p2;
for (p1 = pRequestFilenameMsg->szFileName, p2 = g_szNewFileName;
   '\0' != *p1;
   ++p1, ++p2)
{
   if ('\n' != *p1)
   {
    *p2 = *p1;
   }
   if ('\\' == *p2)
   {
    *(++p2) = '\\';
   }
}
*p2 = '\0';

ReadFile(sClient);

return true;
}

// 传送文件
bool SendFile(SOCKET sClient)
{
if (NULL == g_pBuff)
{
   ReadFile(sClient);
}

int nPacketBufferSize = MAX_PACKET_SIZE - 2 * sizeof(int); // 每个数据包存放文件的buffer大小
// 如果文件的长度大于每个数据包所能传送的buffer长度那么就分块传送
for (int i = 0; i < g_lLength; i += nPacketBufferSize)
{  
   CCSDef::TMSG_FILE tMsgFile;
   tMsgFile.tFile.nStart = i;
   if (i + nPacketBufferSize + 1> g_lLength)
   {
    tMsgFile.tFile.nSize = g_lLength - i;
   }
   else
   {
    tMsgFile.tFile.nSize = nPacketBufferSize;
   }
   //printf("start = %d, size = %d\n", tMsgFile.tFile.nStart, tMsgFile.tFile.nSize);
   memcpy(tMsgFile.tFile.szBuff, g_pBuff + tMsgFile.tFile.nStart, tMsgFile.tFile.nSize);
   ::send(sClient, (char*)(&tMsgFile), sizeof(CCSDef::TMSG_FILE), 0);
   Sleep(0.5);
}

delete [] g_pBuff;
g_pBuff = NULL;

return true;
}

 

/*client.h同server.h*/

/*client.cpp*/

#include "client.h"

long g_lLength = 0;
char* g_pBuff = NULL;
char g_szFileName[MAXFILEDIRLENGTH];
char g_szBuff[MAX_PACKET_SIZE + 1];
SOCKET g_sClient;

// 初始化socket库
bool InitSocket();
// 关闭socket库
bool CloseSocket();
// 把用户输入的文件路径传送到server端
bool SendFileNameToServer();
// 与server端连接
bool ConectToServer();
// 打开文件失败
bool OpenFileError(CCSDef::TMSG_HEADER *pMsgHeader);
// 分配空间以便写入文件
bool AllocateMemoryForFile(CCSDef::TMSG_HEADER *pMsgHeader);
// 写入文件
bool WriteToFile(CCSDef::TMSG_HEADER *pMsgHeader);
// 处理server端传送过来的消息
bool ProcessMsg();

int main()
{
InitSocket();
ConectToServer();
CloseSocket();
return 0;
}

// 初始化socket库
bool InitSocket()
{
// 初始化socket dll
WSADATA wsaData;
WORD socketVersion = MAKEWORD(2, 2);
if (::WSAStartup(socketVersion, &wsaData) != 0)
{
   printf("Init socket dll error\n");
   exit(-1);
}

return true;
}

// 关闭socket库
bool CloseSocket()
{
// 关闭套接字
::closesocket(g_sClient);
// 释放winsock库
::WSACleanup();

return true;
}

// 与server端连接进行文件的传输
bool ConectToServer()
{
// 初始化socket套接字
if (SOCKET_ERROR == (g_sClient = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)))
{
   printf("Init Socket Error!\n");
   exit(-1);
}

sockaddr_in servAddr;
servAddr.sin_family = AF_INET;
servAddr.sin_port = htons(PORT);
servAddr.sin_addr.S_un.S_addr = ::inet_addr(SERVER_IP);
if (INVALID_SOCKET == (::connect(g_sClient, (sockaddr*)&servAddr, sizeof(sockaddr_in))))
{
   printf("Connect to Server Error!\n");
   exit(-1);
}

// 输入文件路径传输到server端
SendFileNameToServer();

// 接收server端传过来的信息,直到保存文件成功为止
while (true == ProcessMsg())
{
}

return true;
}

// 把用户输入的文件路径传送到server端
bool SendFileNameToServer()
{
char szFileName[MAXFILEDIRLENGTH];
printf("Input the File Directory: ");

fgets(szFileName, MAXFILEDIRLENGTH, stdin);

// 把文件路径发到server端
CCSDef::TMSG_FILENAME tMsgRequestFileName;
strcpy(tMsgRequestFileName.szFileName, szFileName);
if (SOCKET_ERROR == ::send(g_sClient, (char*)(&tMsgRequestFileName), sizeof(CCSDef::TMSG_FILENAME), 0))
{
   printf("Send File Name Error!\n");
   exit(-1);
}

return true;
}

// 处理server端传送过来的消息
bool ProcessMsg()
{
CCSDef::TMSG_HEADER *pMsgHeader;
int nRecv = ::recv(g_sClient, g_szBuff, MAX_PACKET_SIZE + 1, 0);

pMsgHeader = (CCSDef::TMSG_HEADER*)g_szBuff;

switch (pMsgHeader->cMsgID)
{
case MSG_OPENFILE_ERROR:   // 打开文件错误
   {
    OpenFileError(pMsgHeader);
   }
   break;
case MSG_FILELENGTH:    // 文件的长度
   {
    if (0 == g_lLength)
    {
     g_lLength = ((CCSDef::TMSG_FILELENGTH*)pMsgHeader)->lLength;
     printf("File Length: %d\n", g_lLength);
    }
   }
   break;
case MSG_FILENAME:     // 文件名
   {
    return AllocateMemoryForFile(pMsgHeader);
   }
   break;
case MSG_FILE:      // 传送文件,写入文件成功之后退出这个函数
   {
    if (WriteToFile(pMsgHeader))
    {
     return false;
    }
   }
   break;
}

return true;
}

// 打开文件失败
bool OpenFileError(CCSDef::TMSG_HEADER *pMsgHeader)
{
if (NULL != g_pBuff)
   return true;
assert(NULL != pMsgHeader);

printf("Cannot find file!Please input again!\n");

// 重新输入文件名称
SendFileNameToServer();

return true;
}

// 查找是否已经存在了要保存的文件,同时分配缓冲区保存文件
bool AllocateMemoryForFile(CCSDef::TMSG_HEADER *pMsgHeader)
{
assert(NULL != pMsgHeader);

if (NULL != g_pBuff)
{
   return true;
}

CCSDef::TMSG_FILENAME* pRequestFilenameMsg = (CCSDef::TMSG_FILENAME*)pMsgHeader;
printf("File Name: %s\n", pRequestFilenameMsg->szFileName);

// 把文件的路径设置为C盘根目录下
strcpy(g_szFileName, "c:\\");
strcat(g_szFileName, pRequestFilenameMsg->szFileName);

// 查找相同文件名的文件是否已经存在,如果存在报错退出
FILE* pFile;
if (NULL != (pFile = fopen(g_szFileName, "r")))
{
   // 文件已经存在,要求重新输入一个文件
   printf("The file already exist!\n");
   CCSDef::TMSG_ERROR_MSG tMsgErrorMsg(MSG_FILEALREADYEXIT_ERROR);
   ::send(g_sClient, (char*)(&tMsgErrorMsg), sizeof(CCSDef::TMSG_ERROR_MSG), 0);

   fclose(pFile);
   return false;
}

// 分配缓冲区开始接收文件,如果分配成功就给server端发送开始传送文件的要求
g_pBuff = new char[g_lLength + 1];
if (NULL != g_pBuff)
{
   memset(g_pBuff, '\0', g_lLength + 1);
   printf("Now ready to get the file %s!\n", pRequestFilenameMsg->szFileName);
   CCSDef::TMSG_CLIENT_READY tMsgClientReady;

   if (SOCKET_ERROR == ::send(g_sClient, (char*)(&tMsgClientReady), sizeof(CCSDef::TMSG_CLIENT_READY), 0))
   {
    printf("Send Error!\n");
    exit(-1);
   }
}
else
{
   printf("Alloc memory for file error!\n");
   exit(-1);
}

return true;
}

// 写入文件
bool WriteToFile(CCSDef::TMSG_HEADER *pMsgHeader)
{
assert(NULL != pMsgHeader);

CCSDef::TMSG_FILE* pMsgFile = (CCSDef::TMSG_FILE*)pMsgHeader;

int nStart = pMsgFile->tFile.nStart;
int nSize = pMsgFile->tFile.nSize;
memcpy(g_pBuff + nStart, pMsgFile->tFile.szBuff, nSize);
if (0 == nStart)
{
   printf("Saving file into buffer...\n");
}

memcpy(g_pBuff + nStart, pMsgFile->tFile.szBuff, nSize);
//printf("start = %d, size = %d\n", nStart, nSize);

// 如果已经保存到缓冲区完毕就写入文件
if (nStart + nSize >= g_lLength)
{
   printf("Writing to disk....\n");
   // 写入文件
   FILE* pFile;
   pFile = fopen(g_szFileName, "w+b");
   fwrite(g_pBuff, sizeof(char), g_lLength, pFile);

   delete [] g_pBuff;
   g_pBuff = NULL;
   fclose(pFile);

   // 保存文件成功传送消息给server退出server
   CCSDef::TMSG_SENDFILESUCCESS tMsgSendFileSuccess;
   while (SOCKET_ERROR == ::send(g_sClient, (char*)(&tMsgSendFileSuccess), sizeof(CCSDef::TMSG_SENDFILESUCCESS), 0))
   {
   }

   printf("Save the file %s success!\n", g_szFileName);

   return true;
}
else
{
   return false;
}
}