C++的socket编程学习

前言

　　不得不承认作为一个前端开发，仍有一个后台开发的梦。从socket通信开始学习,在工作之余补充学习点相关知识，记录下学习的过程。

　　PS:有园友可以推荐点相关的书籍吗？

服务端

　　服务器代码如下,在设置listen之后，通过accept获取对应的socket连接并创建线程进行通信，通信完成后关闭对应线程。

// socket_service.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <stdio.h>
#include <Winsock2.h>
#pragma comment(lib, "ws2_32.lib")

#define LISTEN_MAX_COUNT 5

DWORD WINAPI AnswerThread(LPVOID lparam)
{
    printf("Thread ID:%4d create!\n", GetCurrentThreadId());
    int                 ret;
    char                buf[50] = { 0 };
    char                sendBuf[80] = { 0 };
    SOCKET              clientSocket = (SOCKET)(LPVOID)lparam;
    while (true)
    {
        memset(buf, 0, sizeof(buf));
        ret = recv(clientSocket, buf, sizeof(buf), 0);
        if (ret<=0)
        {
            break;
        }
        printf("revc: %s\n", buf);
        sprintf_s(sendBuf, "Thread ID:%4d revced", GetCurrentThreadId());
        ret = send(clientSocket, sendBuf, strlen(sendBuf) + sizeof(char), 0);
        if (ret <= 0)
        {
            break;
        }
    }
    printf("Thread ID:%4d stop!\n", GetCurrentThreadId());
    closesocket(clientSocket);
    return 1;
}

int _tmain(int argc, _TCHAR* argv[])
{

    WORD wVersionRequested;
    WSADATA wsaData;
    wVersionRequested = MAKEWORD(1, 1);
    if (WSAStartup(wVersionRequested, &wsaData) == INVALID_SOCKET)
    {
        return 0;
    }

    if (LOBYTE(wsaData.wVersion) != 1 ||
        HIBYTE(wsaData.wVersion) != 1) {
        WSACleanup();
        return 0;
    }
    SOCKET sockSrv = socket(AF_INET, SOCK_STREAM, 0);
    int len = sizeof(SOCKADDR);
    SOCKADDR_IN clientAddr;
    SOCKADDR_IN serviceAddr;
    serviceAddr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
    serviceAddr.sin_family = AF_INET;
    serviceAddr.sin_port = htons(27015);

    if (bind(sockSrv, (SOCKADDR*)&serviceAddr, len) == INVALID_SOCKET)
    {
        printf("failed bind!\n");
        closesocket(sockSrv);
        WSACleanup();
        return 0;
    }
    if (listen(sockSrv, LISTEN_MAX_COUNT) == SOCKET_ERROR) {
        printf("Listen failed with error: %ld\n", WSAGetLastError());
        closesocket(sockSrv);
        WSACleanup();
        return 0;
    }

    SOCKET  sockClient;
    HANDLE  hThread = NULL;
    DWORD    dwThreadId;
    while (1)
    {
        sockClient = accept(sockSrv, (SOCKADDR*)&clientAddr, &len);
        Sleep(1000);
        hThread = CreateThread(NULL, NULL, AnswerThread, (LPVOID)sockClient, 0, &dwThreadId);
        if (hThread == NULL)
        {
            printf("CreatThread AnswerThread() failed.\n");
        }
    }

    closesocket(sockSrv);
    WSACleanup();
    return 0;
}

客户端

　　 客户端代码如下,在连接成功后，循环输入进行通信对话。

// socket_client.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <stdio.h>
#include <Winsock2.h>

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

int _tmain(int argc, _TCHAR* argv[])
{

    WORD wVersionRequested;
    WSADATA wsaData;
    int err;

    wVersionRequested = MAKEWORD(1, 1);
    if (WSAStartup(wVersionRequested, &wsaData) == INVALID_SOCKET)
    {
        return -1;
    }

    if (LOBYTE(wsaData.wVersion) != 1 ||
        HIBYTE(wsaData.wVersion) != 1) {
        WSACleanup();
        return -1;
    }

    SOCKET sockClient = socket(AF_INET, SOCK_STREAM, 0);
    int len = sizeof(SOCKADDR);

    SOCKADDR_IN local;
    local.sin_addr.S_un.S_addr = inet_addr("192.168.1.15");
    local.sin_family = AF_INET;
    local.sin_port = htons(27015);

    if (connect(sockClient, (SOCKADDR*)&local, len) == INVALID_SOCKET)
    {
        printf("connect error/n");
        return 0;
    }

    char inputBuf[30];
    char recvBuf[50];
    int ret;
//    while (scanf_s("%s", inputBuf, sizeof(inputBuf)) != EOF)
    while (gets_s(inputBuf))
    {
        if (strcmp(inputBuf, "stop") ==0)
        {
            break;
        }
        ret = send(sockClient, inputBuf, strlen(inputBuf) + sizeof(char), 0);
        if (ret<=0)
        {
            printf("send failed!\n");
            break;
        }
        ret = recv(sockClient, recvBuf, sizeof(recvBuf), 0);
        if (ret <= 0)
        {
            printf("recv failed!\n");
            break;
        }
        printf("my reply is : %s\n", recvBuf);
        //printf("%s\n", inet_ntoa(local.sin_addr));
    }

    closesocket(sockClient);
    WSACleanup();
    return 0;
}

测试

　　Hello World!!

1、开启多个客户端，可以看到服务器如下输出多个线程的创建。

2、客户端输入hello world!，可以得到服务器回复，并告知哪个服务器线程接收了消息。

3、关闭其中一个客户端，可以看到对应线程也关闭了。

4、关闭服务端后，可以端输入任意内容，可以看到客户端也收到提示发送失败并关闭。