Bootstrap

【Socket 编程】基于UDP协议建立多人聊天室

思路

对于服务端来说，除了要接收消息之外，还要实现一个路由转发模块，该路由转发模块可以将相应发送给所有连接的客户端。而对于客户端来说，除了要发送消息给聊天室，还要能实时看到其它所有客户端的消息。
下面来看看具体实现的代码，代码只给出核心模块，其余代码模块代码可以借鉴我之前的博客。具体来说，服务器类实现的功能只有收消息。

路由功能实现

Route.hpp头文件

该头文件实现了一个路由类，该路由类维护了一张用户表和一把锁。该类向外提供转发消息功能的接口。为了实现并发转发消息，这里使用到了之前博客写的线程池，将转发功能的函数提供给线程池里的线程去处理。

#pragma once
#include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <sys/types.h>
#include <sys/socket.h>
#include <pthread.h>
#include <cstring>
#include "InetAddr.hpp"
#include "ThreadPool.hpp"

#include "LockGuard.hpp"
using namespace std;
using task_t = function<void()>;

class Route
{
private:
public:
    Route()
    {
        pthread_mutex_init(&_mutex, nullptr);
    }

    void CheckOnlineUser(InetAddr &who)
    {
        // 用户表是临界资源，需要加锁
        LockGuard lockguard(&_mutex);
        for (auto &user : _online_user)
        {
            if (user == who)
            {
                LOG(DEBUG, "%s is exists!\n", who.AddrStr().c_str());
                return;
            }
        }

        LOG(DEBUG, "%s is not exists,add it!\n", who.AddrStr().c_str());
        _online_user.push_back(who);
    }
    // 下线
    void Offline(InetAddr &who)
    {
        LockGuard lockguard(&_mutex);
        vector<InetAddr>::iterator st = _online_user.begin();
        while (st != _online_user.end())
        {
            if (*st == who)
            {
                _online_user.erase(st);
                LOG(DEBUG, "%s is offline\n", who.AddrStr().c_str());
                break;
            }
            st++;
        }
    }
    void ForwardHelper(int sockfd, const string &message, InetAddr who)
    {
        LockGuard lockguard(&_mutex);
        string send_message = "[" + who.AddrStr() + "]# " + message;

        // 遍历在线用户表，转发给他们
        for (auto &user : _online_user)
        {
            struct sockaddr_in peer = user.Addr();
            LOG(DEBUG, "Forward message to %s\n", user.AddrStr().c_str());
            sendto(sockfd, send_message.c_str(), send_message.size(), 0, (struct sockaddr *)&peer, sizeof(peer));
        }
    }

    // 转发消息给在线用户表
    void Forward(int sockfd, const string &message, InetAddr &who)
    {
        // 查看该用户是否在线，不在线就添加到在线用户中
        CheckOnlineUser(who);

        // 如果用户退出
        if (message == "QUIT" || message == "quit")
        {
            // 下线
            Offline(who);
            return;
        }

        // 创建单例线程池帮助转发

        task_t t = bind(&Route::ForwardHelper, this, sockfd, message, who);
        ThreadPool<task_t>::GetInstance()->Push(t);
    }
    ~Route()
    {
        pthread_mutex_destroy(&_mutex);
    }

private:
    vector<InetAddr> _online_user; // 在线用户表
    pthread_mutex_t _mutex;
};

服务端

UdpServerMain.cpp

服务器的处理逻辑

#include "UdpServer.hpp"
#include <iostream>
#include <string>
#include <memory>
#include "Route.hpp"
using namespace std;

int main(int argc, char *argv[])
{
    if (argc != 2)
    {
        cerr << "Usage:" << argv[0] << " local-port" << endl;
        exit(0);
    }

    uint16_t port = stoi(argv[1]);
    EnableScreen();
    Route messageRoute;
    server_t message_route = bind(&Route::Forward,
                                  &messageRoute, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3);
    std::unique_ptr<UdpServer> usvr = std::make_unique<UdpServer>(message_route, port); // C++14的标准
    usvr->InitServer();
    usvr->Start();
    return 0;
}

UdpServer.hpp

实现一个服务器类

#pragma once
#include <iostream>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string>
#include <cstring>
#include "LockGuard.hpp"
#include "Log.hpp"
#include "nocopy.hpp"
#include "InetAddr.hpp"
#include <functional>
using namespace log_ns;
using namespace std;
static const int gsockfd = -1;
static const uint16_t glocalport = 8888;
using server_t = function<void(int, const string &, InetAddr &)>;
enum
{
    SOCKET_ERROR = 1,
    BIND_ERROR
};

class UdpServer : public nocopy
{
private:
public:
    UdpServer(server_t func, uint16_t localport = glocalport)
        : _localport(localport), _isrunning(false), _sockfd(gsockfd), _fun(func)
    {
    }

    void InitServer()
    {
        // 创建socket
        _sockfd = socket(AF_INET, SOCK_DGRAM, 0); // IPv4协议和UDP协议的套接字
        if (_sockfd < 0)
        {
            LOG(FATAL, "socket create error!\n");
            exit(1);
        }
        LOG(DEBUG, "socket create success,sockfd is %d\n", _sockfd);
        // 绑定端口号和IP
        // 绑定之前创建一个sockaddr_in对象,存储本地地址信息
        struct sockaddr_in local;
        memset(&local, 0, sizeof(local));
        local.sin_family = AF_INET;
        local.sin_addr.s_addr = INADDR_ANY; // 服务器端，进行任意IP地址绑定
        local.sin_port = htons(_localport);

        int n = bind(_sockfd, (struct sockaddr *)&local, sizeof(local));
        if (n < 0)
        {
            LOG(FATAL, "sockfd bind error!\n");
            exit(1);
        }
        LOG(DEBUG, "sockfd bind success!\n");
    }

    void Start()
    {
        _isrunning = true;
        char inbuff[1024];
        while (_isrunning)
        {
            // 获取数据
            struct sockaddr_in peer;
            socklen_t len = sizeof(peer);

            ssize_t n = recvfrom(_sockfd, inbuff, sizeof(inbuff) - 1, 0, (struct sockaddr *)&peer, &len);
            if (n < 0)
            {
                LOG(FATAL, "recvfrom error!\n");
            }
            else
            {
                LOG(DEBUG, "recvfrom success!\n");
                InetAddr addr(peer);
                inbuff[n] = '\0';
                std::string message = inbuff;
                _fun(_sockfd, message, addr);
            }
        }
        _isrunning = false;
    }

    ~UdpServer()
    {
        if (_sockfd >= 0)
            close(_sockfd);
    }

private:
    int _sockfd;
    uint16_t _localport;
    bool _isrunning;
    server_t _fun;
};

客户端

UdpClientMain.cpp

该文件实现了客户端发送消息和接收消息的逻辑，由于发送消息和接收消息需要异步进行，所以可以考虑使用两个线程，分别查看聊天室的消息和向聊天室发送消息

#include <iostream>
#include <string>
#include <cstring>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "Thread.hpp"
#include "InetAddr.hpp"
#include <memory>
#include <functional>
using namespace std;
using namespace ThreadMoudle;

int InitClient()
{
    int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0)
    {
        cerr << "create client failed" << endl;
        exit(1);
    }
    return sockfd;
}

// 发送消息
void SendMessage(int sockfd, string serverip, uint16_t serverport, const string &name)
{
    // 客户端一般不用绑定套接字，操作系统会在第一次发送消息时自动绑定本机ip和一个随机的port
    struct sockaddr_in server;
    memset(&server, 0, sizeof(server));
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr(serverip.c_str());
    server.sin_port = htons(serverport);

    while (true)
    {
        string line;
        cout << name << " #: ";
        getline(cin, line);
        ssize_t res = sendto(sockfd, line.c_str(), line.size(), 0, (struct sockaddr *)&server, sizeof(server));
        if (res <= 0)
        {
            break;
        }
    }
}

// 接收消息
void RecvMessage(int sockfd, const string &name)
{

    while (true)
    {
        struct sockaddr_in peer;
        char buff[1024];
        socklen_t len = 0;
        int n = recvfrom(sockfd, buff, sizeof(buff) - 1, 0, (struct sockaddr *)&peer, &len);
        if (n > 0)
        {
            buff[n] = 0;
            cout << buff << endl;
        }
        else
        {
            cerr << "recvfrom error\n"
                 << endl;
            break;
        }
    }
}

int main(int argc, char *argv[])
{

    if (argc != 3)
    {
        cerr << "Usage:" << argv[0] << " local-port" << endl;
        exit(0);
    }
    string ip = argv[1];
    uint16_t port = stoi(argv[2]);
    int sockfd = InitClient();
    // auto ref = std::bind(&RecvMessage, sockfd, placeholders::_1);
    //  auto senf = std::bind(&SendMessage, sockfd, ip, port, placeholders::_1, placeholders::_2, placeholders::_3);
    Thread recver("recver-thread", std::bind(&RecvMessage, sockfd, std::placeholders::_1));
    Thread sender("sender-thread", std::bind(&SendMessage, sockfd, ip, port, std::placeholders::_1));

    recver.Start();
    sender.Start();
    recver.Join();
    sender.Join();

    close(sockfd);
    return 0;
}

悦读

道可道，非常道；名可名，非常名。 无名，天地之始，有名，万物之母。 故常无欲，以观其妙，常有欲，以观其徼。 此两者，同出而异名，同谓之玄，玄之又玄，众妙之门。

最新收录
redis的高级应用
卷积神经网络超详细介绍
设计模式实例代码－C++版本
【py2neo学习笔记】利用py2neo库来操作neo4j 知识图谱的创建、增加、删除、修改、查询、案例、参考博客
基于小程序154的在线点餐订餐配送系统app微信小程序项目（源码+文档+运行视频+讲解视频）
TCC和XA的区别
盐值加密
专利分析报告：机电管理系统
为什么使用代理IP无法访问网站
[分布式]：分布式系统的CAP理论
;