服務端升級爲select模型處理多客戶端2

對fd_set的理解，可以參考下：
https://www.cnblogs.com/wuyepeng/p/9745573.html

int select(int nfds, fd_set* readset, fd_set* writeset, fe_set* exceptset, struct timeval* timeout);

參數：

nfds 需要檢查的文件描述字個數(集合中最大描述符+1)
readset 用來檢查可讀性的一組文件描述字。
writeset 用來檢查可寫性的一組文件描述字。
exceptset 用來檢查是否有異常條件出現的文件描述字。(注：錯誤不包括在異常條件之內)
timeout 超時，填NULL爲阻塞，填0爲非阻塞，其他爲一段超時時間

返回值：

返回fd的總數，錯誤時返回SOCKET_ERROR

select對集合進行篩選，返回時，只保留符合狀態的描述符
----------------------------------------------------------------------------------------
fd_set fdset;
FD_ZERO(&fdset);
FD_SET(1, &fdset); //將套接字1加入 fdset集合
FD_SET(2, &fdset); //將套接字2加入 fdset集合
FD_SET(3, &fdset); //將套接字3加入 fdset集合
FD_SET(7, &fdset); //將套接字7加入 fdset集合

FD_CLR(3, &fdset); //將套接字3從 fdset 集合移除，fdset.fdReadd_array[2]就被清除了，
數組後面的數據依次往前提，即7被放到了fd_array[2]

服務端：

//vc的第一套socket，第二套socket，可能存在衝突

#define WIN32_LEAN_AND_MEAN
#define  _WINSOCK_DEPRECATED_NO_WARNINGS //也可以放到工程屬性，預處理中

#include <windows.h>
#include <WinSock2.h>
#include <stdio.h>
#include <vector>

#pragma comment(lib, "ws2_32.lib")

enum CMD
{
    CMD_LOGIN,
    CMD_LOGIN_RET,
    CMD_LOGOUT,
    CMD_LOGOUT_RET,
    CMD_ERROR
};


struct DataHeader 
{
    int dataLength;
    CMD    cmd;
};

struct Login :public DataHeader
{
    Login()
    {
        dataLength = sizeof(Login);
        cmd = CMD_LOGIN;
    }
    char userName[32];
    char passWord[32];
};

struct LoginResult :public DataHeader
{
    LoginResult()
    {
        dataLength = sizeof(LoginResult);
        cmd = CMD_LOGIN_RET;
        ret = 0;
    }
    int ret;
};

struct LogOut :public DataHeader
{
    LogOut()
    {
        dataLength = sizeof(LogOut);
        cmd = CMD_LOGOUT;
    }
    char userName[32];
};

struct LogOutResult :public DataHeader
{
    LogOutResult()
    {
        dataLength = sizeof(LogOutResult);
        cmd = CMD_LOGOUT_RET;
        ret = 0;
    }
    int ret;
};

int processor(SOCKET _cSock)
{

    //5 接收客戶端數據
    char szRecv[1024] = {};

    int nLen = recv(_cSock, szRecv, sizeof(DataHeader), 0);
    if (nLen <= 0)
    {
        printf("客戶端%d已退出。\n", _cSock);
        return -1;
    }

    DataHeader* pHeader = (DataHeader*)szRecv;

    switch (pHeader->cmd)
    {
    case CMD_LOGIN:
    {
        recv(_cSock, szRecv + sizeof(DataHeader), pHeader->dataLength - sizeof(DataHeader), 0);
        Login *pLogin = (Login*)szRecv;
        printf("客戶端%d,cmd logint,user:%s,password:%s\n", _cSock, pLogin->userName, pLogin->passWord);
        //----------------------------
        //----------------------------
        LoginResult longinRet = {};
        send(_cSock, (const char*)&longinRet, sizeof(LoginResult), 0);
    }
    break;
    case CMD_LOGOUT:
    {

        recv(_cSock, szRecv + sizeof(DataHeader), pHeader->dataLength - sizeof(DataHeader), 0);
        LogOut *pLogOut = (LogOut*)szRecv;
        printf("客戶端%d,cmd logout,user:%s\n", _cSock, pLogOut->userName);
        //----------------------------
        LogOutResult logOutRet = {};
        send(_cSock, (const char*)&logOutRet, sizeof(LogOutResult), 0);
    }
    break;
    default:
    {
        //剩餘的垃圾數據是否要讀取出來？
        if (pHeader->dataLength >0)
        {
            recv(_cSock, szRecv + sizeof(DataHeader), pHeader->dataLength - sizeof(DataHeader), 0);
        }

        DataHeader header = {};
        header.cmd = CMD_ERROR;
        header.dataLength = 0;
        send(_cSock, (const char*)&header, sizeof(DataHeader), 0);
    }
    break;
    }

    return 0;
}

std::vector<SOCKET> g_clients;

int main()
{
    //啓動Windows socket 2.x環境
    WORD ver = MAKEWORD(2, 2);
    WSADATA dat;
    WSAStartup(ver, &dat);

    //--用Socket API建立簡易TCP服務端
    //1.建立一個socket
    SOCKET _sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    //2 bind綁定用於接受客戶端連接的網絡端口
    sockaddr_in _sin = {};
    _sin.sin_family = AF_INET;
    _sin.sin_port = htons(4567);//host to net unsigned
    _sin.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
    //使用127.0.0.1可以防止外網訪問
    //啓用本機全部的ip地址可以使用，INADDR_ANY
    if (SOCKET_ERROR == bind(_sock, (sockaddr*)&_sin, sizeof(sockaddr_in)))
    {
        printf("錯誤，綁定網絡端口失敗...\n");
    }
    else
    {
        printf("綁定網絡端口成功...\n");
    }
    //3 listen 監聽網絡端口
    if (SOCKET_ERROR == listen(_sock, 5))
    {
        printf("錯誤，監聽網絡端口失敗...\n");
    }
    else
    {
        printf("監聽網絡端口成功...\n");
    }



    while (true)
    {
        fd_set fdRead;
        fd_set fdWrite;
        fd_set fdExp;

        FD_ZERO(&fdRead);
        FD_ZERO(&fdWrite);
        FD_ZERO(&fdExp);

        FD_SET(_sock, &fdRead);
        FD_SET(_sock, &fdWrite);
        FD_SET(_sock, &fdExp);

　　　　　//接入的客戶端socket放入到 可讀集合中，通過select來篩選出具有可讀狀態的socket
        for (size_t n = 0; n<g_clients.size(); n++)
        {
            FD_SET(g_clients[n], &fdRead);
        }


        int ret = select(_sock+1, &fdRead, &fdWrite, &fdExp, nullptr);
        if (ret < 0)
        {
            printf("select任務結束。\n");
            break;
        }

        if ( FD_ISSET(_sock, &fdRead) )
        {
            FD_CLR(_sock, &fdRead);//從集合移除了_sock
            sockaddr_in clientAddr = {};
            int nAddrLen = sizeof(clientAddr);
            SOCKET _cSock = INVALID_SOCKET;

            _cSock = accept(_sock, (sockaddr*)&clientAddr, &nAddrLen);
            if (INVALID_SOCKET == _cSock)
            {
                printf("錯誤，接受到無效客戶端socket...\n");
            }
            g_clients.push_back(_cSock);
            printf("新客戶端加入:socket=%d,IP=%s\n", _cSock, inet_ntoa(clientAddr.sin_addr));
        }

        for (size_t n=0;n<fdRead.fd_count;n++)
        {
            if (-1 == processor(fdRead.fd_array[n]))
            {
                auto iter = find(g_clients.begin(), g_clients.end(), fdRead.fd_array[n]);
                if (iter != g_clients.end())
                {
                    closesocket(*iter);
                    g_clients.erase(iter);
                }
            }
        }


    }

    //6 關閉套接字closesocket
    for (size_t n = 0; n<g_clients.size(); n++)
    {
        closesocket(g_clients[n]);
    }
    closesocket(_sock);


    //清除Windows socket環境
    WSACleanup();
    printf("已退出。\n");
    getchar();
    return 0;
}

客戶端：

#define WIN32_LEAN_AND_MEAN
#define _WINSOCK_DEPRECATED_NO_WARNINGS //也可以放到工程屬性，預處理中
//#define _CRT_SECURE_NO_WARNINGS

#include <windows.h>
#include <WinSock2.h>
#include <stdio.h>


#pragma comment(lib, "ws2_32.lib")

enum CMD
{
    CMD_LOGIN,
    CMD_LOGIN_RET,
    CMD_LOGOUT,
    CMD_LOGOUT_RET,
    CMD_ERROR
};

struct DataHeader
{
    int dataLength;
    CMD    cmd;
};

struct Login:public DataHeader
{
    Login()
    {
        dataLength = sizeof(Login);
        cmd = CMD_LOGIN;
    }
    char userName[32];
    char passWord[32];
};

struct LoginResult :public DataHeader
{
    LoginResult()
    {
        dataLength = sizeof(LoginResult);
        cmd = CMD_LOGIN_RET;
        ret = 1;
    }
    int ret;
};

struct LogOut :public DataHeader
{
    LogOut()
    {
        dataLength = sizeof(LogOut);
        cmd = CMD_LOGOUT;
    }
    char userName[32];
};

struct LogOutResult :public DataHeader
{
    LogOutResult()
    {
        dataLength = sizeof(LogOutResult);
        cmd = CMD_LOGOUT_RET;
        ret = 1;
    }
    int ret;
};

int main()
{

    //啓動Windows socket 2.x環境
    WORD ver = MAKEWORD(2, 2);
    WSADATA dat;
    WSAStartup(ver, &dat);
    //---------------------------
    //--用Socket API建立簡易TCP客戶端
    //1 建立一個socket
    SOCKET _sock = INVALID_SOCKET;
    _sock = socket(AF_INET, SOCK_STREAM, 0);
    if (INVALID_SOCKET == _sock)
    {
        printf("錯誤，建立Socket失敗...\n");
    }
    else
    {
        printf("建立Socket成功...\n");
    }
    //2 連接服務器connect
    sockaddr_in _sin = {};
    _sin.sin_family = AF_INET;
    _sin.sin_port = htons(4567);//host to net unsigned
    _sin.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
    int ret = connect(_sock, (sockaddr*)&_sin, sizeof(sockaddr_in));
    if (SOCKET_ERROR == ret)
    {
        printf("錯誤，連接服務端失敗...\n");


        closesocket(_sock);

        //清除Windows socket環境
        WSACleanup();
        printf("已退出。");
        getchar();
        return 0;
    }
    else
    {
        printf("連接服務端成功...\n");
    }

    
    while (true)
    {
        //3輸入請求命令
        char cmdBuf[128] = {};
        scanf_s("%s", cmdBuf, 128);
        getchar();
        //4處理請求
        if (0 == strcmp(cmdBuf, "exit"))
        {
            printf("收到exit命令，任務結束。\n");
            break;
        }
        else if(0 == strcmp(cmdBuf, "login"))
        {

            Login login = {};
            strcpy_s(login.userName, "jj");
            strcpy_s(login.passWord, "ww");
            int nSend = send(_sock, (const char*)&login, sizeof(Login), 0);
            printf("send length %d\n", nSend);

            LoginResult cmd_ret = {};
            recv(_sock, (char*)&cmd_ret, sizeof(LoginResult), 0);
            printf("Login result:%d\n", cmd_ret.ret);
        }
        else if (0 == strcmp(cmdBuf, "logout"))
        {
            LogOut log_out = {};
            strcpy_s(log_out.userName, "jj");
            send(_sock, (const char*)&log_out, sizeof(LogOut), 0);

            LogOutResult cmd_ret = {};
            recv(_sock, (char*)&cmd_ret, sizeof(LogOutResult), 0);
            printf("LogOut result:%d\n", cmd_ret.ret);
        }
        else
        {
            printf("wrong cmd, please input cmd again.\n");
        }

    }



    //7 關閉套接字closesocket
    closesocket(_sock);

    //清除Windows socket環境
    WSACleanup();
    printf("已退出");
    getchar();
    return 0;
}

服務端升級爲select模型處理多客戶端2

圖片拖動並交換圖片-使用觀察者模式

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27.多線程，分組服務端，1萬客戶端連接，每秒處理200萬包

26.服務端單線程模式下性能瓶頸測試

24.原子操作

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

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