C语言socket实现文件下载

Bertha 。 2022-07-15 02:53 145阅读 0赞

是网络编程的作业，我比较菜。。。写到定位输出，做百分比出现了问题，不显示0到100的，直接从0跳到了100。请教了下大佬。改了过来。原来是类型的问题，做出来的运算应该是float，但是我都定义的int，输出也是，大佬指出后，我好尴尬。。。犯了小错误。。。但是在这次过程也学习了一波。要加油了！！！代码写的这么乱！！！  
写的是带颜色的版本，，颜色有可能会觉得妖艳，，，好吧。  
编译平台是vc++6.0

还是有点bug，有时，客户端发dir命令时会退出。有空再看看。这几天太忙。。。萌新的我只会点C，不会C++。。。如有错误，望大佬指出。谢谢。  
**自己试了下，发现了错误。目录错了！之前因为我两个目录都有要下载的文件。。。改成\\..\\，让他下载的目录返回上一级就好了。又出现了错误，原来拿编译器运行显示的目录和直接exe运行的是不同的。。。。。而且直接exe运行也不会出现dir退出的现象。研究研究**

若要实现返回dos中dir命令的效果只需改成`system("dir>allfiles.txt");`

## sever： ##

#include<winsock2.h>
    #include<windows.h>
    #include<stdio.h>
    #include<Ws2tcpip.h>
    #include<iostream>
    #include<fstream>
    
    #include <direct.h>
    
    #pragma comment(lib,"Ws2_32.lib")
    using namespace std;
    
    #define DEFAULT_BUFLEN 512
    #define DEFAULT_PORT 8088
    #define BUFFER_SIZE 4096
    char    SendBuffer[BUFFER_SIZE],RecvBuffer[BUFFER_SIZE];   //发送缓冲区及接收缓冲区
    SOCKET          AcceptSocket;
    DWORD WINAPI ClientThread(LPVOID lp);
    struct CLIENTINFO{
        SOCKET          clientsocket;
        sockaddr_in     sockaddr;
    };
    
    int main(int argc, TCHAR* argv[])
    {
        int         Ret;
        WSADATA     wsaData;
    
        if((Ret = WSAStartup(MAKEWORD(2,2),&wsaData)) != NO_ERROR)
        {
            printf("WSAStartup failed with error %d\n",Ret);
            return -1;
        }//if
    
        // Create a new socket to listening for client connections.
        SOCKET      ListenSocket;
        if((ListenSocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP)) 
            == INVALID_SOCKET)
        {
            printf("socket failed with error %d\n",WSAGetLastError());
            WSACleanup();
            return -1;
        }//if
    
        sockaddr_in     service;
        service.sin_family = AF_INET;
        service.sin_addr.s_addr = inet_addr("127.0.0.1");
        service.sin_port = htons(DEFAULT_PORT);
    
        if(bind(ListenSocket,(SOCKADDR* ) &service,sizeof(service)) == SOCKET_ERROR)
        {
            printf("bind failed with error %d\n",WSAGetLastError());
            closesocket(ListenSocket);
            WSACleanup();
            return -1;
        }//if
    
        if(listen(ListenSocket, 10) == SOCKET_ERROR)
        {
            printf("Error listening on socket.\n");
            closesocket(ListenSocket);
            WSACleanup();
            return -1;
        }//if
    
        SOCKET          AcceptSocket;
        sockaddr_in     ClientAddr;//接收客户端地址
        int     addrClientlen = sizeof(ClientAddr);
        while(true)
        {
    
            CLIENTINFO      clientInfo;
            printf("waiting for client to connect......\n");
            AcceptSocket = accept(ListenSocket,(sockaddr* ) &ClientAddr, &addrClientlen);
            if(AcceptSocket == INVALID_SOCKET)
            {
                printf("accept failed : %d\n",WSAGetLastError());
                closesocket(ListenSocket);
                WSACleanup();
                return 1;
            }//if
            clientInfo.clientsocket = AcceptSocket;
            memcpy(&clientInfo.sockaddr,&ClientAddr,sizeof(sockaddr_in));
            printf("a client is coming......\n");
            DWORD dwThreadID;
            CreateThread(NULL,0,ClientThread,(LPVOID* )&clientInfo,0,&dwThreadID);
        }//while
        closesocket(ListenSocket);
        WSACleanup();
        return 0;
    } //main
    
    
    DWORD WINAPI ClientThread(LPVOID lp)
    {
        CLIENTINFO *pClientInfo = (CLIENTINFO* )lp;
        SOCKET  clientsocket = pClientInfo->clientsocket;
        sockaddr_in sockaddr;
        memcpy(&sockaddr,&pClientInfo->sockaddr,sizeof(sockaddr_in));
        int     iResult,bytes;
        char    recvRFileName[DEFAULT_BUFLEN] = "";
        char    temp_buffer[BUFFER_SIZE];
        unsigned readlen;
        DWORD dwReadSize = 0;
        char   curPath[MAX_PATH]; 
        char quit [10] ="quit";
        //获得相对路径
        GetModuleFileName(NULL,(LPSTR)curPath,sizeof(curPath));
        strrchr( curPath, '\\')[0]= 0;
    
        ifstream infile;
        while(true)
        {
            memset(recvRFileName,0,sizeof(recvRFileName));
            iResult = recv(clientsocket,recvRFileName,DEFAULT_BUFLEN,0);
            if(SOCKET_ERROR == iResult)
            {
                printf("recvieve failed with error : %d\n",WSAGetLastError());
                closesocket(clientsocket);
                WSACleanup();
                return -1;
            }//if
    
    
            //命令有get help exit -s(文件大小)
    
            //help
            char dir [10] ="dir";
            char get [10] ="get";
            printf("传过来的数据:%s",recvRFileName);
    
            if(strcmp(recvRFileName,dir)==0){
            //返回命令
            system("cmd /c dir /a-d /b >allfiles.txt");
            printf("查看allfiles文件\n");
    
                //将打印出来的文件信息读取出来
    
            FILE *file;
    char buf[1024];
    int len=0,i=0;
    char *array[1024];
    char filedir [1024];//要传过去的文件目录
    
    file=fopen("allfiles.txt","r");//打开TXST.TxT文件
    if(!file)return -1;
    while(fgets(buf,1024,file))//读取TXT中字符
    {
     len=strlen(buf);
     array[i]=(char*)malloc(len+1);
     if(!array[i])break;
     strcpy(array[i++],buf);
    }//while
    
    fclose(file);
    i--;
    while(i>=0&&array[i])
    {
     printf("%s\n",array[i]);//打印test文档的字符
    
        iResult = send(clientsocket,array[i],strlen(array[i]),0);
        if(iResult==SOCKET_ERROR){
       printf("发送失败\n");}
    
        free(array[i--]);
    
    }//while
            printf("发送结束quit\n");
        send(clientsocket,quit,strlen(quit),0);
                continue;
    
            }//if
    
            //完整文件名
            strcat(curPath,"\\");
            strcat(curPath,recvRFileName);
            strcpy( recvRFileName,curPath);
    
    
    
                            //获取文件大小
    
            FILE * pFile;
          long size;
          pFile = fopen (recvRFileName,"rb");
          if (pFile==NULL)
                perror ("Error opening file");
          else
          {
                fseek (pFile, 0, SEEK_END);   ///将文件指针移动文件结尾
                size=ftell (pFile); ///求出当前文件指针距离文件开始的字节数
                fclose (pFile);
                printf ("FileSize : %ld bytes.\n",size);
                    char a[30];
                    //将size保存在字符串a中
                sprintf(a,"%d",size);
                send(clientsocket, a, 30, 0);
                    printf("发送文件大小:%s",a);
          }
    
    
            printf("文件：%s\n",recvRFileName);
            infile.open(recvRFileName,ios::in|ios::binary);
    
            if(!infile)
            {    //未成功打开文件
                printf("Sorry, cannot open %s. Please try again.\r\n",recvRFileName);
                //break;
            }//if
    
            else
            {
                printf("The file %s is found,ready to transfer.\n",recvRFileName);
                printf("Transfering\r\n"); 
    
    
    
                while (!infile.eof())
                {    //循环读取文件并通过h_NewSocket发送到客户端
                    //printf(SendBuffer,"%s",temp_buffer); 
                    infile.read(SendBuffer,BUFFER_SIZE);
                    readlen = infile.gcount();
                    send(clientsocket, SendBuffer, readlen, 0);
                    //printf("."); 
                }
                infile.close();
                printf("Transfer completed... \r\n"); 
    
    
                //bytes = send(AcceptSocket, SendBuffer, strlen(SendBuffer), 0);
    
            }//else 
    
    
    
    
        //如果没有数据发送
        iResult = shutdown(clientsocket,SD_BOTH);
        if (iResult == SOCKET_ERROR) {
            printf("shutdown failed: %d\n", WSAGetLastError());
        }//if
    
        closesocket(clientsocket);
        return 0;
    
    
        }//while
    }//main

## client： ##

#include<winsock2.h>
    #include<windows.h>
    #include<Ws2tcpip.h>
    #include<stdio.h>
    #include<string>
    #include<iostream>
    #include<fstream>
    
    using namespace std;
    
    #pragma comment(lib,"Ws2_32.lib")
    
    #define DEFAULT_BUFLEN 512
    #define DEFAULT_PORT 5150
    #define BUFFER_SIZE 4096
    
    int main(int argc, TCHAR* argv[])
    {
        int         iResult,rec;
        WSADATA     wsaData;
        HANDLE hout;
        ofstream    outfile;
        SOCKET ConnectSocket = INVALID_SOCKET;
        struct sockaddr_in clientService;
        char    sendbuf[DEFAULT_BUFLEN] = "";
        char    szBuffer[BUFFER_SIZE];
        BOOL    issend = true;
    
        //初始化Windows Sockets DLL
        if(iResult = WSAStartup(MAKEWORD(2,2),&wsaData) != NO_ERROR)
        {
            printf("WSAStartup failed with error : %d\n",iResult);
            return -1;
        }
        //创建socket
        ConnectSocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
        if(ConnectSocket == INVALID_SOCKET)
        {
            printf("socket failed with error : %d\n",WSAGetLastError());
            WSACleanup();
            return -1;
        }
        
    
         char addr[20];
       int prot ;
       printf("现在运行的是客户端！\n");
       printf("**************************************************************\n");
       printf("请输入服务器的IP地址:");
       scanf("%s",addr);
       printf("请输入服务器的端口:");
        scanf("%d",&prot);
    
    
    
        ///
    
    
        //设置目的网络地址并连接服务器
        clientService.sin_family = AF_INET;
        clientService.sin_addr.s_addr = inet_addr(addr);
        clientService.sin_port = htons(prot);
        iResult = connect(ConnectSocket,(SOCKADDR* )&clientService,sizeof(clientService));
        if(iResult == SOCKET_ERROR)
        {
            printf("connect failed with error : %d\n",WSAGetLastError());
            closesocket(ConnectSocket);
            WSACleanup();
            return -1;
        }
    
        printf("connect with server successfully!!!\n");
                    hout = GetStdHandle(STD_OUTPUT_HANDLE);  
     SetConsoleTextAttribute(hout,  
                                FOREGROUND_GREEN);   
            cout<<"输入命令:******************* help 获取命令提示**********************:\n";
        while(true)
        {
    
    
    
            //输入命令：
            char cmd [20];
            char help [10] ="help";
            char exit [10] ="exit";
            char get [10] ="get";
            char dir [10] ="dir";
            char quit [10] ="quit";
            scanf("%s",&cmd);
            printf("输入的命令是%s\n",cmd);
            if(strcmp(cmd,help)==0){
    
    
                printf("命令参数:\n help----------获取命令帮助\n dir----------获取文件目录\n get----------下载文件\n exit----------退出\n");
                    continue;
            }
            // 列目录
            if(strcmp(cmd,dir)==0){
    
            iResult = send(ConnectSocket,dir,strlen(dir),0);
    
            if(SOCKET_ERROR == iResult)
            {
                printf("send failed with error : %d\n",WSAGetLastError());
                closesocket(ConnectSocket);
                WSACleanup();
                return -1;
            }
            //接收传过来的目录
    
            SetConsoleTextAttribute(hout,  
                                FOREGROUND_GREEN |   
                                FOREGROUND_BLUE);  
            printf("**********************文件目录**********************\n");
            char dirs [30];
    
    
            while(true){
                    ZeroMemory(dirs,30);
                iResult = recv(ConnectSocket,dirs,30,0);
                //数据发送完成就跳出循环，结束时，服务器发过来quit
                if(strcmp(dirs,quit)==0){
       break;}
    
                else
                printf("%s\n",dirs);
    
    
                if(SOCKET_ERROR == iResult)
            {
                printf("recvieve failed with error : %d\n",WSAGetLastError());
                closesocket(ConnectSocket);
                WSACleanup();
                return -1;
            }//if
    
                            //接收完再次返回
                    // continue;
            }//while
                continue;
            }//if
    
    
    
            if(strcmp(cmd,exit)==0){
       break;}
    
        if((strcmp(cmd,dir)!=0)&&(strcmp(cmd,exit)!=0)&&(strcmp(cmd,help)!=0)&&(strcmp(cmd,get)!=0)){
            printf("命令参数:\n help----------获取命令帮助\n dir----------获取文件目录\n get----------下载文件\n exit----------退出\n");
                                continue;
    
        } 
    
    
            if(strcmp(cmd,get)==0){
                SetConsoleTextAttribute(hout, FOREGROUND_INTENSITY | FOREGROUND_RED); 
                printf("您输入的命令是get，下载文件，请依次输入要下载的文件名、保存本地文件名\n");
    
    
    
    
    
            //文件下载 参数get后使用
            char  str[20];
            //文件名
            scanf("%s",&str);
            ZeroMemory(sendbuf,DEFAULT_BUFLEN);
            strcpy(sendbuf,str);
            if(strcmp(str,quit)==0){
    
    
    
            printf("您输入了exit，退出get\n");
                continue;
            }
    
                SetConsoleTextAttribute(hout,  
                                FOREGROUND_RED |   
                                FOREGROUND_GREEN |   
                                FOREGROUND_BLUE);  
            iResult = send(ConnectSocket,sendbuf,strlen(sendbuf),0);
            if(SOCKET_ERROR == iResult)
            {
                printf("send failed with error : %d\n",WSAGetLastError());
                closesocket(ConnectSocket);
                WSACleanup();
                return -1;
            }
    
            //接收文件总大小
                int size;
                char sizestr [30];
                recv(ConnectSocket,sizestr,30,0);
                size = strtol (sizestr,NULL,10);
    
                    SetConsoleTextAttribute(hout,  
                                FOREGROUND_BLUE |   
                                FOREGROUND_RED);
    
                printf("总的数据大小：%ld\n",size);
    
            //cout<<"输入存放文件（路径+文件名）:\n";
            char    CFileName[DEFAULT_BUFLEN] = "";
                scanf("%s",&CFileName);
    
    
            SetConsoleTextAttribute(hout, FOREGROUND_INTENSITY|FOREGROUND_RED|FOREGROUND_BLUE|FOREGROUND_GREEN );
    
            printf("保存文件：%s\n",CFileName);
    
            outfile.open(CFileName,ios::out|ios::binary);
    
            if(!outfile)   //打开文件准备写入
            {    
                printf("Error of opening file !");
    
                iResult = shutdown(ConnectSocket, SD_SEND);
                iResult = closesocket(ConnectSocket);
                WSACleanup();
                return -1;
            }
    
    
            COORD   coord;
    
            CONSOLE_SCREEN_BUFFER_INFO csbi;
    
            hout=GetStdHandle(STD_OUTPUT_HANDLE);
            GetConsoleScreenBufferInfo(hout,&csbi);
            coord.X =csbi.dwCursorPosition.X;
            coord.Y =csbi.dwCursorPosition.Y;
    
            float cnt = 0;
    
            while(issend)
            {
                //读取流 
    
                rec = recv(ConnectSocket,szBuffer,BUFFER_SIZE,0);
                cnt+=rec;
                if(rec == 0)
                {
                    SetConsoleTextAttribute(hout, FOREGROUND_INTENSITY | FOREGROUND_RED);
                    printf("Download completed ! \n");
                    break;
                }
                else if(rec == SOCKET_ERROR)
                {
                    printf("Receive function failed with error : %d\n ",WSAGetLastError());
                    break;
                }
    
                SetConsoleCursorPosition(hout,coord);   
                SetConsoleTextAttribute(hout, FOREGROUND_INTENSITY | FOREGROUND_GREEN);
    
                printf("Received %f%% bytes \n",cnt/size*100);
                outfile.write(szBuffer,rec);            
    
            }
    
            SetConsoleTextAttribute(hout, FOREGROUND_INTENSITY | FOREGROUND_BLUE);
            printf("Transfer is completed!\n");
            SetConsoleTextAttribute(hout, FOREGROUND_INTENSITY|FOREGROUND_RED|FOREGROUND_BLUE|FOREGROUND_GREEN );
    
            outfile.close();    
    
        }
    
        // 若没有数据要发送，单向关闭连接
        iResult = shutdown(ConnectSocket, SD_SEND);
        // Step 6: 关闭连接
        iResult = closesocket(ConnectSocket);
    
        WSACleanup();
        return 0;
    
    }
    }

## 效果： ##

![这里写图片描述][20161030220811225]

![这里写图片描述][20161030220824940]

![这里写图片描述][20161030220836913]

![这里写图片描述][20161030220847065]

## 计算传输的时间： ##

只要在传输文件的代码写上：

time_t start ,end ;  
                double cost;  
                time(&start);  
                printf("开始计算传输时间\n");

传输完成写上：

//传输完成。输出时间
                            time(&end); 
                cost=difftime(end,start); 
                printf("传输时间:%f\n",cost);

**要加上windows.h和time.h**

[20161030220811225]: /images/20220715/61e4cb3c8bd04d15bb571ef3780c041d.png
[20161030220824940]: /images/20220715/9c6f03413ed742dfa23d4c84304a9b74.png
[20161030220836913]: /images/20220715/731504b7e75b46a8930fb4f4c8d17972.png
[20161030220847065]: /images/20220715/1fb2713053af458181f85f893bac219b.png