【在Linux世界中追寻伟大的One Piece】connect的断线重连

目录

1 -> connect的断线重连


1 -> connect的断线重连

客户端会面临服务器崩溃的情况,我们可以试着写一个客户端重连的代码,模拟并理解一些客户端行为,比如游戏客户端等。

TcpClient.cc

采用状态机,实现一个简单的tcp client可以实现重连效果。

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
using namespace std;

void Usage(const std::string& process)
{
    std::cout << "Usage: " << process << " server_ip server_port" << std::endl;
}

enum class Status // C++11 强类型枚举
{
    NEW,        // 新建状态,就是单纯的连接
    CONNECTING, // 正在连接,仅仅方便查询conn状态
    CONNECTED,  // 连接或者重连成功
    DISCONNECTED, // 重连失败
    CLOSED        // 连接失败,经历重连,无法连接
};

class ClientConnection
{
public:
    ClientConnection(uint16_t serverport, const std::string& serverip)
        : _sockfd(-1),
        _serverport(serverport),
        _serverip(serverip),
        _retry_interval(1),
        _max_retries(5),
        _status(Status::NEW)
    {
    }

    void Connect()
    {
        // 1. 创建socket
        _sockfd = socket(AF_INET, SOCK_STREAM, 0);
        if (_sockfd < 0)
        {
            cerr << "socket error" << endl;
            exit(1);
        }

        // 2. 要不要bind?必须要有Ip和Port, 需要bind,但是不需要用户显示的bind,client系统随机端口
        // 发起连接的时候,client会被OS自动进行本地绑定
        // 2. connect
        struct sockaddr_in server;
        memset(&server, 0, sizeof(server));

        server.sin_family = AF_INET;
        server.sin_port = htons(_serverport);
        // p:process(进程), n(网络) -- 不太准确,但是好记忆
        inet_pton(AF_INET, _serverip.c_str(), &server.sin_addr); // 1. 字符串ip->4字节IP 2. 网络序列

        int n = connect(_sockfd, (struct sockaddr*)&server, sizeof(server)); // 自动进行bind哦!
        if (n < 0)
        {
            Disconnect();                   // 恢复_sockfd的默认值,是连接没有成功,不代表sockfd创建没有成功
            _status = Status::DISCONNECTED; // 没有连接成功

            return;
        }

        _status = Status::CONNECTED; // 连接成功
    }

    int SocketFd()
    {
        return _sockfd;
    }

    void Reconnect()
    {
        _status = Status::CONNECTING; // 正在重连

        int count = 0;
        while (count < _max_retries)
        {
            Connect(); // 重连
            if (_status == Status::CONNECTED)
            {
                return;
            }

            sleep(_retry_interval);
            count++;
            std::cout << "重连次数: " << count << ", 最大上限: " << _max_retries << std::endl;
        }

        _status = Status::CLOSED; // 重连失败,可以关闭了
    }

    void Disconnect()
    {
        if (_sockfd != -1)
        {
            close(_sockfd);
            _status = Status::CLOSED;
            _sockfd = -1;
        }
    }

    Status GetStatus()
    {
        return _status;
    }

    void Process()
    {
        // 简单的IO即可
        while (true)
        {
            string inbuffer;

            cout << "Please Enter# ";

            getline(cin, inbuffer);
            if (inbuffer.empty()) 
                continue;

            ssize_t n = write(_sockfd, inbuffer.c_str(), inbuffer.size());
            if (n > 0)
            {
                char buffer[1024];
                ssize_t m = read(_sockfd, buffer, sizeof(buffer) - 1);
                if (m > 0)
                {
                    buffer[m] = 0;
                    cout << "echo messsge -> " << buffer << endl;
                }
                else if (m == 0) // 这里证明server端掉线了
                {
                    _status = Status::DISCONNECTED;
                    break;
                }
                else
                {
                    std::cout << "read m : " << m << "errno: " << errno << "errno string: " << strerror(errno) << std::endl;
                    _status = Status::CLOSED;
                    break;
                }
            }
            else
            {
                std::cout << "write n : " << n << "errno: " << errno << "errno string: " << strerror(errno) << std::endl;
                _status = Status::CLOSED;
                break;
            }
        }
    }

    ~ClientConnection()
    {
        Disconnect();
    }

private:
    int _sockfd;
    uint16_t _serverport;  // server port 端口号
    std::string _serverip; // server ip地址
    int _retry_interval;   // 重试时间间隔
    int _max_retries;      // 重试次数
    Status _status;        // 连接状态
};

class TcpClient
{
public:
    TcpClient(uint16_t serverport, const std::string& serverip) : _conn(serverport, serverip)
    {
    }

    void Execute()
    {
        while (true)
        {
            switch (_conn.GetStatus())
            {
            case Status::NEW:
                _conn.Connect();
                break;
            case Status::CONNECTED:
                std::cout << "连接成功, 开始进行通信." << std::endl;
                _conn.Process();
                break;
            case Status::DISCONNECTED:
                std::cout << "连接失败或者对方掉线,开始重连." << std::endl;
                _conn.Reconnect();
                break;
            case Status::CLOSED:
                _conn.Disconnect();
                std::cout << "重连失败, 退出." << std::endl;
                return; // 退出
            default:
                break;
            }
        }
    }

    ~TcpClient()
    {
    }

private:
    ClientConnection _conn; // 简单组合起来即可
};
// class Tcp

// ./tcp_client serverip serverport
int main(int argc, char* argv[])
{
    if (argc != 3)
    {
        Usage(argv[0]);
        return 1;
    }

    std::string serverip = argv[1];

    uint16_t serverport = stoi(argv[2]);
    TcpClient client(serverport, serverip);

    client.Execute();

    return 0;
}

感谢各位大佬支持!!!

互三啦!!!

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转载自blog.csdn.net/weixin_74809706/article/details/143100319