Linux网络-自定义协议、序列化和反序列化、网络计算服务器的实现和Windows端客户端

文章目录

前言
一、自定义协议
- 传结构体对象
序列化和反序列化
- 什么是序列化？
- 反序列化
二、计算器服务端（线程池版本）
- 1.main.cc
- 2.Socket.hpp
- 3.protocol.hpp
- 4.Calculator.hpp
- 5.serverCal.hpp
- 6.threadPool.hpp
- 7.Task.hpp
- 8. log.hpp
客户端
Windows客户端
运行

前言

我们已经学会了Tcp、Udp网络传输协议，并且之前我们也实现了简易的聊天室和翻译器。

我们知道，传输层是OS系统里就给我们写好的，应用层才是我们自己需要去编写的，现在我们对应用层来进行一些初步的了解。

一、自定义协议

在之前我们使用Tcp和Udp服务进行网络通信，我们一直都是以字符串的形式互相发送消息。

那么我们就只能发送字符串吗？当然不是，Udp是基于数据流进行网络通信，Udp是基于字节流进行网络通信，虽然我们对字节流和数据流并没有一个特别清晰的认识，但是我们可以知道的是，我们其实是可以传各种各样的类型进行通行的。

这里就提出一种方案

传结构体对象

从我们之前写的代码来看，只要我们在发送数据和接收数据时制定一个协议，每次只读写一个结构体对象的大小，那么我们就可以将该结构体进行通信。而实际上，底层的很多库也确实是这么做的，但是这并不代表这种方式不存在明显弊端。

最大的弊端就是，你能保证在不同环境之下，同样的结构体类型在不同主机、不同环境下的大小是一样的吗。结构体的大小涉及到许多，比如说结构体字节对齐，32位和64位系统下内置类型大小可能不同…

所以我们并不推崇这种方案。

而实际上我们其实更推崇传字符串的方式。

序列化和反序列化

什么是序列化？

在现实生活中，我们介绍自己，有些人习惯先说自己的名字，有些人习惯先说自己来自于哪一个城市。如果你需要去统计大量的人的信息，最好就是先列一个表格，然后让他们严格按照表格上的个人信息顺序去介绍自己，这就是序列化。

再比如说我们今天要写一个网络版本的计算器，我可以写成1+1，也可以写成一加一，再也可以写写成1 + 1，中间带几个空格。那么这样的话，我们服务器接受到的数据就是形形色色的，不利于我们去解析。

于是我们就制定一个协议，你必须要写成"1 + 1"的形式，否则就是违反协议！

反序列化

反序列化很简单，就比如说我们收到了一段数据，它是一个字符串形式的"1 + 1"，我们就需要将该字符串进行解析，反序列化成int x = 1, char op = ‘+’ , int y = 1.
这也是一种反序列化。

二、计算器服务端（线程池版本）

1.main.cc

#include "serverCal.hpp"

void Usage(const char *mes)
{
    std::cout << "Usage: " << mes << " port[8080-9000]" << std::endl;
}

const std::string default_ip = "0.0.0.0";

enum{
    Usage_Err = 1
};

int main(int argc, char *argv[])
{
    if (argc != 2)
    {
        Usage("./serverCal");
        exit(Usage_Err);
    }
    ServerCal sc;
    sc.Init(AF_INET, default_ip, atoi(argv[1]));
    sc.Run();
    return 0;
}

2.Socket.hpp

对套接字进行封装

#pragma once

#include <iostream>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include "log.hpp"
enum
{
    Socket_Err = 1,
    Bind_Err,
    Listen_Err
};

extern Log lg;

const int backlog = 10;

class Socket
{
public:
    Socket()
        : _sockfd(-1)
    {
    }

    int Getfd()
    {
        return _sockfd;
    }
    void Init()
    {
        int socket_fd = socket(AF_INET, SOCK_STREAM, 0);
        if (socket_fd < 0)
        {
            lg(Fatal, "Socket Create Failed...");
            exit(Socket_Err);
        }
        lg(Info, "Socket Create Succeeded...");

        _sockfd = socket_fd;
    }

    void Bind(const int sinfamily, const std::string &ip, const uint16_t port)
    {
        memset(&_sockaddr, 0, sizeof _sockaddr);
        switch (sinfamily)
        {
        case AF_INET:
            _sockaddr.sin_family = AF_INET;
            break;
        case AF_INET6:
            _sockaddr.sin_family = AF_INET6;
            break;
        }
        _sockaddr.sin_port = htons(port);
        inet_aton(ip.c_str(), &(_sockaddr.sin_addr));
        int n = bind(_sockfd, (const struct sockaddr *)&_sockaddr, sizeof _sockaddr);
        if (n < 0)
        {
            lg(Fatal, "Bind Failed...");
            exit(Bind_Err);
        }
        lg(Info, "Bind Succeeded..., port: %d", port);
    }

    void Listen()
    {
        int n = listen(_sockfd, backlog);
        if (n < 0)
        {
            lg(Fatal, "Listen Failed...");
            exit(Listen_Err);
        }
        lg(Info, "Listen Succeeded...");
    }

    int Accept(struct sockaddr_in *clientsock, socklen_t *len)
    {
        int fd = accept(_sockfd, (sockaddr *)clientsock, len);
        if (fd < 0)
        {
            lg(Warning, "Accept Failed...");
            return -1;
        }
        lg(Info, "Accept Succeeded..., Get A new Link, fd: %d", fd);

        return fd;
    }

    int Connect(const std::string &ip, const std::string &port)
    {
        struct sockaddr_in serversock;
        serversock.sin_port = htons(atoi(port.c_str()));
        serversock.sin_family = AF_INET;
        inet_aton(ip.c_str(), &serversock.sin_addr);

        int n = connect(_sockfd, (const struct sockaddr *)&serversock, sizeof serversock);
        if (n < 0)
        {
            lg(Warning, "Accept Failed...");
            return n;
        }
        lg(Info, "Connect Succeeded...");
        return n;
    }

    ~Socket()
    {
        close(_sockfd);
    }

private:
    int _sockfd;
    struct sockaddr_in _sockaddr;
};

3.protocol.hpp

序列化和反序列化的协议制定

#pragma once
#include <iostream>
#include <string>
#include "log.hpp"

extern Log lg;
const char blank_space_sep = ' ';
const char protocol_sep = '\n';

enum Code
{
    Div_Zero_Err = 1,
    Mod_Zeor_Err,
    Operatorr_Err
};

class Request
{
public:
    Request() {} // 提供一个无参构造

    Request(int x, int y, char op)
        : _x(x), _y(y), _operator(op) {}

    bool serialize(std::string *out_str)
    {
        // 协议规定 字符串格式应序列化为"len\n""_x + _y\n"
        std::string main_body = std::to_string(_x);
        main_body += blank_space_sep;
        main_body += _operator;
        main_body += blank_space_sep;
        main_body += std::to_string(_y);
        *out_str = std::to_string(main_body.size());
        *out_str += protocol_sep;
        *out_str += main_body;
        *out_str += protocol_sep;
        return true;
    }

    bool deserialize(std::string &in_str)
    {
        // 协议规定 in_str的格式应为"len\n""_x + _y\n..."
        size_t pos = in_str.find(protocol_sep);
        if (pos == std::string::npos)
        {
            // 说明没找到'\n'
            lg(Warning, "Message Format Error..., No Found The First Second \\n");
            return false;
        } 
        std::string sl = in_str.substr(0, pos);
        int len = std::stoi(sl); // 如果这里的sl不是一串数字，stoi就会抛异常！ BUG
        int total_len = sl.size() + 1 + len + 1;
        if (in_str.size() < total_len)
        {
            lg(Warning, "Message Format Error..., Lenth Error");
            return false;
        }
        if (in_str[total_len - 1] != '\n')
        {
            
            lg(Warning, "Message Format Error..., No Found The Second \\n");
            return false;
        }

        std::string main_body = in_str.substr(pos + 1, len);
        // main_body"_x +  _y"
        int left = main_body.find(blank_space_sep);
        if (left == std::string::npos)
        {
            // 说明没找到' '
            lg(Warning, "Message Format Error..., No Found The First ' '");
            return false;
        }
        int right = main_body.rfind(blank_space_sep);
        if (left == right)
        {
            // 说明只有一个' '
            lg(Warning, "Message Format Error...,No Found The Second ' '");
            return false;
        }
        _x = std::stoi(main_body.substr(0, left));   // 如果这里的sl不是一串数字，stoi就会抛异常！ BUG
        _y = std::stoi(main_body.substr(right + 1)); // 如果这里的sl不是一串数字，stoi就会抛异常！ BUG
        _operator = main_body[left + 1];
        in_str.erase(0, total_len);
        return true;
    }

    void print()
    {
        std::cout << _x << " " << _operator << " " << _y << std::endl;
    }
    ~Request() {}

public:
    int _x;
    int _y;
    char _operator;
};

class Respond
{
public:
    Respond() {} // 提供一个无参构造

    Respond(int result, int code)
        : _result(result), _code(code) {}

    bool serialize(std::string *out_str)
    {
        // 协议规定 字符串格式应序列化为"_result _code"
        *out_str = std::to_string(_result);
        *out_str += blank_space_sep;
        *out_str += std::to_string(_code);
        return true;
    }

    bool deserialize(const std::string &in_str)
    {
        // 协议规定 in_str的格式应为"_result _code"
        size_t pos = in_str.find(blank_space_sep);
        if (pos == std::string::npos)
        {
            // 没找到字符' '
            lg(Warning, "Result Message Error...");
            return false;
        }
        _result = std::stoi(in_str.substr(0, pos));
        _code = std::stoi(in_str.substr(pos + 1));
        return true;
    }

    void print()
    {
        std::cout << _result << " " << _code << std::endl;
    }

    ~Respond() {}

public:
    int _result;
    int _code = -1; // 表示结果可信度  0表示可信
};

4.Calculator.hpp

计算器功能接口函数

#pragma once
#include"protocol.hpp"

class Calculator{
    public:
    Calculator() {}

    Respond calculate(const Request& rq)
    {
        Respond rs;
        switch (rq._operator)
        {
            case '+':
            rs._result = rq._x + rq._y;
            break;
            case '-':
            rs._result = rq._x - rq._y;
            break;
            case '*':
            rs._result = rq._x * rq._y;
            break;
            case '/':
            if(rq._y == 0)
            {
                lg(Warning,"Found Div Zero Error...");
                rs._code = Div_Zero_Err;
                return rs;
            }
            rs._result = rq._x / rq._y;
            break;
            case '%':
            if(rq._y == 0)
            {
                lg(Warning,"Found Mod Zero Error...");
                rs._code = Mod_Zeor_Err;
                return rs;
            }
            rs._result = rq._x - rq._y;
            break;
            default:
            lg(Warning,"Found Operator Error...");
            rs._code = Operatorr_Err;
            return rs;
        }
        rs._code = 0;
        return rs;
    }
};

5.serverCal.hpp

代码如下（示例）：

#pragma once

#include "Socket.hpp"
#include "protocol.hpp"
#include "threadPool.hpp"
#include "Task.hpp"
class ServerCal
{
public:
    ServerCal()
    {
    }

    void Init(const int sinfamily, const std::string &ip, const uint16_t port)
    {
        _listensock.Init();
        _listensock.Bind(sinfamily, ip, port);
        _listensock.Listen();
    }

    void Run()
    {
        ThreadPool<Task> *tp = ThreadPool<Task>::GetInstance();
        tp->Start();
        struct sockaddr_in client;


        while (true)
        {
            memset(&client, 0, sizeof client);
            socklen_t len;
            int socketfd = _listensock.Accept(&client, &len);
            if (socketfd < 0)
                continue;
            tp->Push(socketfd);
        }
    }

private:
    Socket _listensock;
};

6.threadPool.hpp

很熟悉的线程池封装

#pragma once

#include <iostream>
#include <vector>
#include <string>
#include <queue>
#include <pthread.h>
#include <unistd.h>

struct ThreadInfo
{
    pthread_t tid;
    std::string name;
};

static const int defalutnum = 10;

template <class T>
class ThreadPool
{
public:
    void Lock()
    {
        pthread_mutex_lock(&mutex_);
    }
    void Unlock()
    {
        pthread_mutex_unlock(&mutex_);
    }
    void Wakeup()
    {
        pthread_cond_signal(&cond_);
    }
    void ThreadSleep()
    {
        pthread_cond_wait(&cond_, &mutex_);
    }
    bool IsQueueEmpty()
    {
        return tasks_.empty();
    }
    std::string GetThreadName(const pthread_t tid)
    {
        for (const auto &ti : threads_)
        {
            if (ti.tid == tid)
                return ti.name;
        }
        return "None";
    }

public:
    static void *HandlerTask(void *args)
    {
        ThreadPool<T> *tp = static_cast<ThreadPool<T> *>(args);
        std::string name = tp->GetThreadName(pthread_self());
        while (true)
        {
            tp->Lock();

            while (tp->IsQueueEmpty())
            {
                tp->ThreadSleep();
            }
            T t = tp->Pop();
            tp->Unlock();

            t();
        }
    }
    void Start()
    {
        int num = threads_.size();
        for (int i = 0; i < num; i++)
        {
            threads_[i].name = "thread-" + std::to_string(i + 1);
            pthread_create(&(threads_[i].tid), nullptr, HandlerTask, this);
        }
    }
    T Pop()
    {
        T t = tasks_.front();
        tasks_.pop();
        return t;
    }
    void Push(const T &t)
    {
        Lock();
        tasks_.push(t);
        Wakeup();
        Unlock();
    }
    static ThreadPool<T> *GetInstance()
    {
        if (nullptr == tp_) // ???
        {
            pthread_mutex_lock(&lock_);
            if (nullptr == tp_)
            {
                // std::cout << "log: singleton create done first!" << std::endl;
                tp_ = new ThreadPool<T>();
            }
            pthread_mutex_unlock(&lock_);
        }

        return tp_;
    }

private:
    ThreadPool(int num = defalutnum) : threads_(num)
    {
        pthread_mutex_init(&mutex_, nullptr);
        pthread_cond_init(&cond_, nullptr);
    }
    ~ThreadPool()
    {
        pthread_mutex_destroy(&mutex_);
        pthread_cond_destroy(&cond_);
    }
    ThreadPool(const ThreadPool<T> &) = delete;
    const ThreadPool<T> &operator=(const ThreadPool<T> &) = delete; // a=b=c
private:
    std::vector<ThreadInfo> threads_;
    std::queue<T> tasks_;

    pthread_mutex_t mutex_;
    pthread_cond_t cond_;

    static ThreadPool<T> *tp_;
    static pthread_mutex_t lock_;
};

template <class T>
ThreadPool<T> *ThreadPool<T>::tp_ = nullptr;

template <class T>
pthread_mutex_t ThreadPool<T>::lock_ = PTHREAD_MUTEX_INITIALIZER;

7.Task.hpp

派发给线程池的任务

#pragma once
#include "Socket.hpp"
#include "protocol.hpp"
#include "Calculator.hpp"
class Task
{
public:
    Task(int socket_fd)
        : _socket_fd(socket_fd)
    {
    }

    void run()
    {
        char in_buffer[1024];
        Calculator cal;
        std::string message = "";
        while (true)
        {
            memset(in_buffer, 0, sizeof in_buffer);
            //std:: cout << "开始等待读取..." <<std::endl;
            int n = read(_socket_fd, (void *)in_buffer, sizeof in_buffer - 1);
            //std::cout << n << " " << strerror(errno) <<std::endl;
            //std::cout << "读取到的有效字符为" << n << std::endl;
            if (n == 0)
            {
                lg(Warning, "Connection closed by foreign host, socketfd[%d] closed...", _socket_fd);
                break;
            }
            else if (n < 0)
            {
                lg(Warning, "Read Error, socketfd[%d]...", _socket_fd);
                break;
            }
            in_buffer[n] = 0;
            message += in_buffer;
            //std::cout << "报文大小: "<< message.size() <<" ,报文内容: "<< message << std::endl;
            Request rq;
            if(!rq.deserialize(message))  continue;
            Respond rs = cal.calculate(rq);
            std::string res;
            rs.serialize(&res);
            printf("%d %c %d = %d\n",rq._x,rq._operator,rq._y,rs._result);
            write(_socket_fd, res.c_str(), res.size());
        }
    }
    void operator()()
    {
        run();
        close(_socket_fd);
    }

    ~Task()
    {}

private:
    int _socket_fd;
};

8. log.hpp

输出日志消息

#pragma once

#include <iostream>
#include <time.h>
#include <stdarg.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

#define SIZE 1024

#define Info 0
#define Debug 1
#define Warning 2
#define Error 3
#define Fatal 4

#define Screen 1
#define Onefile 2
#define Classfile 3

#define LogFile "log.txt"

class Log
{
public:
    Log()
    {
        printMethod = Screen;
        path = "./log/";
    }
    void Enable(int method)
    {
        printMethod = method;
    }
    std::string levelToString(int level)
    {
        switch (level)
        {
        case Info:
            return "Info";
        case Debug:
            return "Debug";
        case Warning:
            return "Warning";
        case Error:
            return "Error";
        case Fatal:
            return "Fatal";
        default:
            return "None";
        }
    }

    void printLog(int level, const std::string &logtxt)
    {
        switch (printMethod)
        {
        case Screen:
            std::cout << logtxt << std::endl;
            break;
        case Onefile:
            printOneFile(LogFile, logtxt);
            break;
        case Classfile:
            printClassFile(level, logtxt);
            break;
        default:
            break;
        }
    }
    void printOneFile(const std::string &logname, const std::string &logtxt)
    {
        std::string _logname = path + logname;
        int fd = open(_logname.c_str(), O_WRONLY | O_CREAT | O_APPEND, 0666); // "log.txt"
        if (fd < 0)
            return;
        write(fd, logtxt.c_str(), logtxt.size());
        close(fd);
    }
    void printClassFile(int level, const std::string &logtxt)
    {
        std::string filename = LogFile;
        filename += ".";
        filename += levelToString(level); // "log.txt.Debug/Warning/Fatal"
        printOneFile(filename, logtxt);
    }

    ~Log()
    {
    }
    void operator()(int level, const char *format, ...)
    {
        time_t t = time(nullptr);
        struct tm *ctime = localtime(&t);
        char leftbuffer[SIZE];
        snprintf(leftbuffer, sizeof(leftbuffer), "[%s][%d-%d-%d %d:%d:%d]", levelToString(level).c_str(),
                 ctime->tm_year + 1900, ctime->tm_mon + 1, ctime->tm_mday,
                 ctime->tm_hour, ctime->tm_min, ctime->tm_sec);

        va_list s;
        va_start(s, format);
        char rightbuffer[SIZE];
        vsnprintf(rightbuffer, sizeof(rightbuffer), format, s);
        va_end(s);

        // 格式：默认部分+自定义部分
        char logtxt[SIZE * 2];
        snprintf(logtxt, sizeof(logtxt), "%s %s", leftbuffer, rightbuffer);

        // printf("%s", logtxt); // 暂时打印
        printLog(level, logtxt);
    }

private:
    int printMethod;
    std::string path;
};

Log lg;

客户端

#include "Socket.hpp"
#include "protocol.hpp"

void Usage(const char *mes)
{
    std::cout << "Usage: " << mes << " ip[xxx.xxx.xxx.xxx] port[8080-9000]" << std::endl;
}

int main(int argc, char *argv[])
{
    if (argc != 3)
    {
        Usage("./clientCal");
    }
    Socket local;
    local.Init();
    int n = local.Connect(argv[1], argv[2]);
    if (n < 0)
    {
        return 1;
    }

    int localfd = local.Getfd();

    std::cout << "       简易计算器, 目前仅支持\" + - * / %\"运算符 " << std::endl;
    std::cout << "       数字和运算符请用空格或回车隔开" << std::endl;
    Request rq;
    Respond rs;
    std::string message;
    char buffer[1024];
    while (true)
    {
        memset(buffer, 0, sizeof buffer);
        std::cout << "请输入您的算式@ ";
        std::cin >> rq._x >> rq._operator >> rq._y;
        rq.serialize(&message);
        write(localfd, message.c_str(), message.size());

        // 开始等待结果
        n = read(localfd, buffer, sizeof buffer - 1);
        if (n == 0)
        {
            lg(Warning, "Connection closed by foreign host, socketfd[%d] closed...",localfd);
            break;
        }
        else if (n < 0)
        {
            lg(Warning, "Read Error, socketfd[%d]...", localfd);
            break;
        }
        buffer[n] = 0;
        std::string res = buffer;
        rs.deserialize(res);
        if(rs._code != 0)
        {
            switch(rs._code)
            {
                case 1:
                std::cout << "出现除0错误" << std::endl;
                break;
                case 2:
                std::cout << "出现模0错误" << std::endl;
                break;
                case 3:
                std::cout << "使用了除 + - * / % 以外的运算符" << std::endl;
                break;
                default:
                std::cout << "发生未知错误" <<std::endl;
                break;
            }
            continue;
        }
        printf("%d %c %d = %d\n",rq._x,rq._operator,rq._y,rs._result);
    }
    return 0;
}

Windows客户端

#include<iostream>
#include<string>
#include<WinSock2.h>
#include<Windows.h>
#include<functional>
#include<stdlib.h>
#include"protocol.hpp"


#pragma comment(lib, "ws2_32.lib")
#pragma warning(disable:4996)
#pragma execution_character_set("utf-8")


const int server_port = 8889;
const std::string server_ip = "43.143.58.29";

int main()
{
    //初始化网络环境
    WSADATA wsd;
    WSAStartup(MAKEWORD(2, 2), &wsd);
    system("chcp 65001");

    //申请套接字
    SOCKET socket_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (socket_fd == SOCKET_ERROR)
    {
        perror("Socket Error");
        exit(1);
    }
    

    //创建并初始化Server端sockaddr_in结构体
    struct sockaddr_in server;
    memset(&server, 0, sizeof server);
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr(server_ip.c_str());
    server.sin_port = htons(server_port);

    //开始连接服务器
    int n = connect(socket_fd, (const struct sockaddr*)&server, sizeof server);
    if (n < 0)
    {
        //连接失败
        std::cout << "Connect Failed" << std::endl;
        return 1;
    }

    std::cout << "       简易计算器, 目前仅支持\" + - * / %\"运算符 " << std::endl;
    std::cout << "       数字和运算符请用空格或回车隔开" << std::endl;
    Request rq;
    Respond rs;
    std::string message;
    char buffer[1024];
    while (true)
    {
        memset(buffer, 0, sizeof buffer);
        std::cout << "请输入您的算式@ ";
        std::cin >> rq._x >> rq._operator >> rq._y;
        rq.serialize(&message);
        send(socket_fd, message.c_str(), (int)message.size(),0);

        // 开始等待结果
        n = recv(socket_fd, buffer, sizeof buffer - 1,0);
        if (n == 0)
        {
            lg(Warning, "Connection closed by foreign host, socketfd[%d] closed...", socket_fd);
            break;
        }
        else if (n < 0)
        {
            lg(Warning, "Read Error, socketfd[%d]...", socket_fd);
            break;
        }
        buffer[n] = 0;
        std::string res = buffer;
        rs.deserialize(res);
        if (rs._code != 0)
        {
            switch (rs._code)
            {
            case 1:
                std::cout << "出现除0错误" << std::endl;
                break;
            case 2:
                std::cout << "出现模0错误" << std::endl;
                break;
            case 3:
                std::cout << "使用了除 + - * / % 以外的运算符" << std::endl;
                break;
            default:
                std::cout << "发生未知错误" << std::endl;
                break;
            }
            continue;
        }
        printf("%d %c %d = %d\n", rq._x, rq._operator, rq._y, rs._result);
    }


    //清理环境
    closesocket(socket_fd);
    WSACleanup();
    return 0;
}