C++ 网络编程 socket(结构化数据传输)

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结构化数据传输

server

// ctrl + k + c
//  Ctrl + K+ U 
#define WIN32_LEAN_AND_MEAN

#include <iostream>
#include <Windows.h>
#include <WinSock2.h>

using namespace std;
//加入静态连接库
#pragma comment(lib,"ws2_32.lib")
//输出目录 $(SolutionDir)..bin/$(Platform)/$(Configuration)\
//中间目录 $(SolutionDir)../temp/$(Platform)/$(Configuration)/$(ProjectName)\

struct DataPackage {
	int age;
	char name[32];
	//在客户端声明时也要保持该格式,字节对齐
};

int main()
{
	//启动windows socket 2.x环境
	WORD ver = MAKEWORD(2, 2);
	WSADATA dat;
	WSAStartup(ver, &dat);
	//---------------------------
	//TCP 服务端
	//启动windows scoket编程环境
	//1.建立一个socket

	SOCKET _sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	//ipv4 数据流 TCP


	//2.绑定接受客户端连接的端口号bind
	sockaddr_in _sin = {};//
	_sin.sin_family = AF_INET;//网络类型 ipv4
	_sin.sin_port = htons(4567);// host to net unsigned short 端口号 主机数据转换到网络数据,无符号数据类型

	_sin.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");// 服务器的ip地址
													   //当不知道自己的本机ip地址时可以写为 INADDR_ANY
	if (bind(_sock, (sockaddr*)&_sin, sizeof(_sin)) == SOCKET_ERROR)
	{
		cout << "绑定用于接收客户端连接的网络端口失败" << endl;
	}
	else {
		cout << "绑定网络端口成功..." << endl;
	}//网络端口是否被占用

	 //3.监听网络端口listen
	if (listen(_sock, 5) == SOCKET_ERROR)//等待连接的队列的长度
	{
		cout << "监听网络端口失败..." << endl;
	}
	else {
		cout << "监听网络端口成功..." << endl;
	}
	//4.等待接受客户端连接accept
	sockaddr_in clientAddr = {};//客户端的地址和端口
	int nAddrLen = sizeof(sockaddr_in);
	SOCKET _cSock = INVALID_SOCKET;
	
	_cSock = accept(_sock, (sockaddr *)&clientAddr, &nAddrLen);
	if (_cSock == INVALID_SOCKET)
	{
		cout << "错误,接收到无效客户端SOCKET..." << endl;
	}
	else
	{
		cout << "接收数据客户端有效..." << endl;
	}
	cout << "新客户端加入:socket = " << _cSock << ", IP = " << inet_ntoa(clientAddr.sin_addr) /*转换为 字符串 刻度的字符串数字*/ << endl;
	char _recvBuf[128] = {};//接收缓存区
	while (true)
	{
		//5.接收客户端的请求数据
		int nLen = recv(_cSock, _recvBuf, 128, 0);
		if (nLen <= 0)
		{
			cout << "客户端已退出,任务结束" << endl;
			break;
		}
		cout << "收到命令:" << _recvBuf << endl;
		//6.处理请求
		if (strcmp(_recvBuf, "getInfo") == 0) {
			//7.向客户端发送一条数据send
			DataPackage dp = {80,"张国荣"};
			send(_cSock, (const char*)&dp, sizeof(DataPackage), 0);//strlen(msgBuf) + 1 将结尾符一并发送过去
		}
		//if (strcmp(_recvBuf, "getName") == 0) {
		//	char msgBuf[] = "Xiao Qiang!";
		//	//7.向客户端发送一条数据send
		//	send(_cSock, msgBuf, strlen(msgBuf) + 1, 0);//strlen(msgBuf) + 1 将结尾符一并发送过去
		//}
		//else if (strcmp(_recvBuf, "getAge") == 0) {
		//	char msgBuf[] = "18";
		//	send(_cSock, msgBuf, strlen(msgBuf) + 1, 0);//strlen(msgBuf) + 1 将结尾符一并发送过去
		//}

		else {
			char msgBuf[] = "hello ,I'm server!";
			send(_cSock, msgBuf, strlen(msgBuf) + 1, 0);//strlen(msgBuf) + 1 将结尾符一并发送过去
		}
		
	}
	//8.关闭socket closesocket
	closesocket(_sock);

	//----------------------------
	//清除windows socket环境
	WSACleanup();
	getchar();
	return 0;
}

client

#define WIN32_LEAN_AND_MEAN

#include <iostream>
#include <Windows.h>
#include <WinSock2.h>

using namespace std;
//加入静态连接库
#pragma comment(lib,"ws2_32.lib")
//输出目录 $(SolutionDir)..bin/$(Platform)/$(Configuration)\
//中间目录 $(SolutionDir)../temp/$(Platform)/$(Configuration)/$(ProjectName)\

struct DataPackage {
	int age;
	char name[32];
	//在客户端声明时也要保持该格式,字节对齐
};

int main()
{
	//启动windows socket 2.x环境
	WORD ver = MAKEWORD(2, 2);
	WSADATA dat;
	WSAStartup(ver, &dat);
	//-----------------------------
	//TCP客户端
	//1.建立一个socket
	SOCKET _sock = socket(AF_INET, SOCK_STREAM, 0);
	if (_sock == INVALID_SOCKET)
	{
		cout << "连接服务器失败..." << endl;
	}
	else {
		cout << "连接服务器成功.." << endl;
	}
	//2.连接服务器connect
	sockaddr_in _sin = {};
	_sin.sin_family = AF_INET;
	_sin.sin_port = htons(4567);
	_sin.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");//声明服务端地址
	int ret = connect(_sock, (sockaddr*)(&_sin), sizeof(sockaddr_in));
	if (ret == SOCKET_ERROR)
	{
		cout << "连接服务器失败" << endl;
	}
	else {
		cout << "连接服务器成功" << endl;
	}
	while (true)
	{
		//3.输入请求命令
		char cmdBuf[128] = {};
		//cin >> cmdBuf;
		scanf("%s", cmdBuf);
		//4.处理请求
		if (strcmp(cmdBuf, "exit") == 0) {
			cout << "已退出客户端,任务结束!" << endl;
			break;
		}
		else {
			//5.把命令发送给服务端
			send(_sock, cmdBuf, strlen(cmdBuf) + 1, 0);
		}
		//6.接受服务器信息recv
		char recBuf[256] = {};//创建数据缓冲区
		int nlen = recv(_sock, recBuf, 256, 0);
		if (nlen > 0) {
			DataPackage *dp = (DataPackage *)recBuf;
			cout << "接受的数据为:age: " << dp->age << ", name: "<< dp->name << endl;
		}
		else {
			cout << "接受数据失败" << endl;
		}
	}
	
	//7.关闭socket closesocket
	closesocket(_sock);
	//----------------------------
	//清除windows socket环境
	WSACleanup();
	getchar();
	return 0;
}

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以上命名格式输入错误的时,强制类型转换带来的不安全;

2. 网络数据报文

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* 报文有两个部分,包头和包体,是网络消息的基本单元;
* 包头:描述本次消息包的大小,描述数据的作用;
*包体:数据;

2.1 server

// ctrl + k + c
//  Ctrl + K+ U 
#define WIN32_LEAN_AND_MEAN

#include <iostream>
#include <Windows.h>
#include <WinSock2.h>

using namespace std;
//加入静态连接库
#pragma comment(lib,"ws2_32.lib")
//输出目录 $(SolutionDir)..bin/$(Platform)/$(Configuration)\
//中间目录 $(SolutionDir)../temp/$(Platform)/$(Configuration)/$(ProjectName)\

enum CMD{
	CMD_LOGIN,
	CMD_LOGOUT,
	LOG_ERROR
};
//消息头
struct  DataHeader{
	short dataLength;//数据长度
	short cmd;//
};
//DataPackage
struct Login{
	char userName[32];
	char PassWord[32];
};
struct LoginResult {
	int result;
};

struct LogOut
{
	char userName[32];
};
struct LogOutResult {
	int result;
};

int main()
{
	//启动windows socket 2.x环境
	WORD ver = MAKEWORD(2, 2);
	WSADATA dat;
	WSAStartup(ver, &dat);
	//---------------------------
	//TCP 服务端
	//启动windows scoket编程环境
	//1.建立一个socket

	SOCKET _sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	//ipv4 数据流 TCP


	//2.绑定接受客户端连接的端口号bind
	sockaddr_in _sin = {};//
	_sin.sin_family = AF_INET;//网络类型 ipv4
	_sin.sin_port = htons(4567);// host to net unsigned short 端口号 主机数据转换到网络数据,无符号数据类型

	_sin.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");// 服务器的ip地址
													   //当不知道自己的本机ip地址时可以写为 INADDR_ANY
	if (bind(_sock, (sockaddr*)&_sin, sizeof(_sin)) == SOCKET_ERROR)
	{
		cout << "绑定用于接收客户端连接的网络端口失败" << endl;
	}
	else {
		cout << "绑定网络端口成功..." << endl;
	}//网络端口是否被占用

	 //3.监听网络端口listen
	if (listen(_sock, 5) == SOCKET_ERROR)//等待连接的队列的长度
	{
		cout << "监听网络端口失败..." << endl;
	}
	else {
		cout << "监听网络端口成功..." << endl;
	}
	//4.等待接受客户端连接accept
	sockaddr_in clientAddr = {};//客户端的地址和端口
	int nAddrLen = sizeof(sockaddr_in);
	SOCKET _cSock = INVALID_SOCKET;
	
	_cSock = accept(_sock, (sockaddr *)&clientAddr, &nAddrLen);
	if (_cSock == INVALID_SOCKET)
	{
		cout << "错误,接收到无效客户端SOCKET..." << endl;
	}
	else
	{
		cout << "接收数据客户端有效..." << endl;
	}
	cout << "新客户端加入: socket = " << _cSock << ", IP = " << inet_ntoa(clientAddr.sin_addr) /*转换为 字符串 刻度的字符串数字*/ << endl;
	
	while (true)
	{
		DataHeader header = {};
		//5.接收客户端的请求数据
		int nLen = recv(_cSock,(char*)&header, sizeof(DataHeader), 0);
		if (nLen <= 0)
		{
			cout << "客户端已退出,任务结束" << endl;
			break;
		}
		cout << "收到命令:数据命令:" << header.cmd<< ",数据长度:"<< header.dataLength << endl;
		//6.处理请求

		switch (header.cmd) {
			case CMD_LOGIN: 
			{
				Login login = {};
				recv(_cSock, (char*)&login, sizeof(Login), 0);
				LoginResult ret = {1};
				//忽略判断用户名和密码是否正确
				send(_cSock, (char*)&header, sizeof(DataHeader), 0);
				send(_cSock, (char*)&ret, sizeof(LoginResult), 0);
			}
			break;
			case CMD_LOGOUT: 
			{
				LogOut logOut = {};
				recv(_cSock, (char*)&logOut, sizeof(LogOut), 0);
				LogOutResult ret = { 1 };
				//忽略判断用户名和密码是否正确
				send(_cSock, (char*)&header, sizeof(DataHeader), 0);
				send(_cSock, (char*)&ret, sizeof(LogOutResult), 0);
			}
			 break;
			default:
			{
				header.cmd = LOG_ERROR;
				header.dataLength = 0;
				send(_cSock, (char *)&header, sizeof(header), 0);//strlen(msgBuf) + 1 将结尾符一并发送过去
				break;
			}
		}	
	}
	//8.关闭socket closesocket
	closesocket(_sock);

	//----------------------------
	//清除windows socket环境
	WSACleanup();
	getchar();
	return 0;
}

2.2 client

#define WIN32_LEAN_AND_MEAN

#include <iostream>
#include <Windows.h>
#include <WinSock2.h>

using namespace std;
//加入静态连接库
#pragma comment(lib,"ws2_32.lib")
//输出目录 $(SolutionDir)..bin/$(Platform)/$(Configuration)\
//中间目录 $(SolutionDir)../temp/$(Platform)/$(Configuration)/$(ProjectName)\

enum CMD {
	CMD_LOGIN,
	CMD_LOGOUT,
	LOG_ERROR
};
//消息头
struct  DataHeader {
	short dataLength;//数据长度
	short cmd;//
};
//DataPackage
struct Login {
	char userName[32];
	char PassWord[32];
};
struct LoginResult {
	int result;
};

struct LogOut
{
	char userName[32];
};
struct LogOutResult {
	int result;
};


int main()
{
	//启动windows socket 2.x环境
	WORD ver = MAKEWORD(2, 2);
	WSADATA dat;
	WSAStartup(ver, &dat);
	//-----------------------------
	//TCP客户端
	//1.建立一个socket
	SOCKET _sock = socket(AF_INET, SOCK_STREAM, 0);
	if (_sock == INVALID_SOCKET)
	{
		cout << "连接服务器失败..." << endl;
	}
	else {
		cout << "连接服务器成功.." << endl;
	}
	//2.连接服务器connect
	sockaddr_in _sin = {};
	_sin.sin_family = AF_INET;
	_sin.sin_port = htons(4567);
	_sin.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");//声明服务端地址
	int ret = connect(_sock, (sockaddr*)(&_sin), sizeof(sockaddr_in));
	if (ret == SOCKET_ERROR)
	{
		cout << "连接服务器失败" << endl;
	}
	else {
		cout << "连接服务器成功" << endl;
	}
	while (true)
	{
		//3.输入请求命令
		char cmdBuf[128] = {};
		//cin >> cmdBuf;
		scanf("%s", cmdBuf);
		//4.处理请求
		//5.把命令发送给服务端
		if (strcmp(cmdBuf, "exit") == 0) {
			cout << "已退出客户端,任务结束!" << endl;
			break;
		}
		else if (strcmp(cmdBuf, "login") == 0) {
			Login login = { "jmm","lovely" };
			DataHeader dh = {sizeof(login),CMD_LOGIN };
			//5.把命令发送给服务端
			send(_sock, (char*)&dh, sizeof(dh), 0);
			send(_sock, (char *)&login, sizeof(login), 0);
			// 接受服务器返回的数据
			DataHeader retHeader = {};
			LoginResult loginRet = {};
			recv(_sock, (char*)&retHeader, sizeof(retHeader), 0);
			recv(_sock, (char*)&loginRet, sizeof(loginRet), 0);
			cout << "LoginResult: " << loginRet.result << endl;
		}
		else if (strcmp(cmdBuf, "logout") == 0) {
			LogOut logout = {};
			DataHeader dh = {sizeof(logout),CMD_LOGOUT };
			//5.把命令发送给服务端
			send(_sock, (char *)&dh, sizeof(dh), 0);
			send(_sock, (char *)&logout, sizeof(logout), 0);
			// 接受服务器返回的数据
			DataHeader retHeader = {};
			LoginResult logoutRet = {};
			recv(_sock, (char*)&retHeader, sizeof(retHeader), 0);
			recv(_sock, (char*)&logoutRet, sizeof(logoutRet), 0);
			cout << "LogOutResult: " << logoutRet.result << endl;
		}
		else {
			cout << "不支持该命令,请重新输入!" << endl;
		}
	}
	
	//7.关闭socket closesocket
	closesocket(_sock);
	//----------------------------
	//清除windows socket环境
	WSACleanup();
	getchar();
	return 0;
}

2.3 运行结果

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