Windows网络模型之Select模型以一个聊天室服务端为例

#ifndef FD_SETSIZE
#define FD_SETSIZE      64
#endif /* FD_SETSIZE */

typedef struct fd_set {
        u_int   fd_count;               /* how many are SET? */
        SOCKET  fd_array[FD_SETSIZE];   /* an array of SOCKETs */
} fd_set;
//u_int   fd_count 结构体成员的个数
//SOCKET  fd_array[FD_SETSIZE]; socket类型的数组，默认最多有64个客户端连接

		fd_set reads;

		// 清空或者初始化reads
		FD_ZERO(&reads);

		// 设置sockServer到reads
		FD_SET(sockServer, &reads);

int WSAAPI select(
  [in]      int           nfds,
  [in, out] fd_set        *readfds,
  [in, out] fd_set        *writefds,
  [in, out] fd_set        *exceptfds,
  [in]      const timeval *timeout
);

select(int nfds,fd_set *readfds,fd_set *writefds,fd_set *exceptfds,const timeval *timeout);
    //    select(0, 0, 0, 0, 0);

	while (1)
	{
		fd_set reads;

		// 清空或者初始化reads
		FD_ZERO(&reads);

		// 设置sockServer到reads
		FD_SET(sockServer, &reads);

		for (auto v : g_clients)
		{
			FD_SET(v->clientSock, &reads);
		}
		int sRet = select(0, &reads, 0, 0, 0);

		// 表示select超时或者出错
		if (sRet <= 0) continue;

		if (FD_ISSET(sockServer, &reads)) {
			printf("服务端响应\n");
			SOCKADDR_IN clientAddr = {};
			int nAddrLen = sizeof(SOCKADDR_IN);
			SOCKET sockClient = accept(sockServer, (sockaddr*)&clientAddr, &nAddrLen);
			if (INVALID_SOCKET == sockClient) {
				printf("接收客户端连接失败\n");
				return -1;
			}
			std::cout << "开始处理客户端: " << std::endl;
			UserInfo* user = new UserInfo{ false, "undefined", sockClient };
			g_clients.push_back(user);
		}
		for (auto v : g_clients) {
			if (FD_ISSET(v->clientSock, &reads))
			{
				SelectClientConnection(v->clientSock, v);
			}
		}
	}

#define _WINSOCK_DEPRECATED_NO_WARNINGS
#include <ws2tcpip.h>
#include <winsock2.h>
#include <windows.h>
#include <iostream>
#include <thread>
#include <vector>

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

class UserInfo
{
public:
	bool isLogin = false; //是否登陆
	std::string _userName; //客户端的用户名
	SOCKET clientSock;   //客户端的socket

	UserInfo(bool isLogin, std::string _userName, SOCKET clientSock) :isLogin(isLogin), _userName(_userName), clientSock(clientSock)
	{

	}
};

std::vector<UserInfo*> g_clients; //用于服务端存储用户登陆信息

//  判定用户是否处在登陆状态函数
//  INPUIT: const std::string&  userName  用户姓名
//  RETURN: bool  true:在线 false:不在线
bool isUserLoggedIn(const std::string& _userName)
{
	for (const auto& user : g_clients)
	{
		if (user->_userName == _userName && user->isLogin)
			return true;
	}
	return false;
}

//  广播信息函数
//  INPUIT: SOCKET selfSock 客户端的Sock描述符, const char* msg  广播信息
//  广播信息给除了特定客户端以外的所有客户端信息
void SendMsg(SOCKET selfSock, const char* msg)
{
	int msglen = strlen(msg);
	for (int i = 0; i < g_clients.size(); i++)
	{
		if (g_clients[i]->clientSock == selfSock)continue;
		send(g_clients[i]->clientSock, msg, msglen, 0);
	}
}

//  分割字符串函数
//  INPUIT: const std::string& s 待分割字符串, char delimiter 分割符号
//  RETURN: std::vector<std::string>  存储分割的字符串的数组
std::vector<std::string> splitString(const std::string& s, char delimiter)
{
	std::vector<std::string> result;
	std::string path;
	for (size_t i = 0; i < s.size(); i++) 
	{
		if (s[i] != delimiter)
		{
			path.push_back(s[i]);
		}
		else if (!path.empty()) // 确保path非空时才push_back
		{
			result.push_back(path);
			path.clear();
		}
	}
	if (!path.empty()) // 处理字符串以分隔符结尾的情况
	{
		result.push_back(path);
	}
	return result;
}

//  客户端的Select处理函数
//  INPUIT: SOCKET clientSocket 客户端对应的SOCKET, UserInfo* currentUser 客户端对应的用户
void SelectClientConnection(SOCKET clientSocket, UserInfo* currentUser)
{
	char szData[1024] = {};
	int ret = recv(clientSocket, szData, sizeof(szData), 0);
	if (ret > 0)
	{
		std::cout << "收到数据: [" << szData << "]" << std::endl;
		std::vector<std::string> splits = splitString(szData, '|');

		if (splits[0] == "Login")
		{
			// 验证用户是否已登录
			if (isUserLoggedIn(splits[1]))
			{
				char loginFailedMsg[64];
				snprintf(loginFailedMsg, sizeof(loginFailedMsg), "Error|%s|LoginFailed", splits[1].c_str());
				send(clientSocket, loginFailedMsg, sizeof(loginFailedMsg), 0);
				return;
			}
			// 用户未登录，创建并登录
			currentUser->isLogin = true;
			currentUser->_userName = splits[1];

		}
		else if (splits[0] == "其它命令")
		{

		}
		else
		{
			std::string chatMsg;
			chatMsg.append(currentUser->_userName);
			chatMsg.append(":");
			chatMsg.append(szData);
			//chatMsg = currentUser->_userName + ":" + szData;
			SendMsg(INVALID_SOCKET, chatMsg.c_str());
		}
	}
	else if (ret <= 0)
	{
		std::cout << "客户端断开链接" << std::endl;
		if (currentUser->_userName != "undefined")
		{
			for (auto it = g_clients.begin(); it != g_clients.end(); ++it)
			{
				// 找到并移除对应的UserInfo对象
				if (*it == currentUser)
				{
					std::cout << "User:" << currentUser->_userName << "is erase!" << std::endl;
					delete currentUser;
					g_clients.erase(it);
					break;
				}
			}
		}
		closesocket(currentUser->clientSock);
	}
}

int main()
{
	// 0. 初始化网络环境
	WSADATA wsaData = {};
	WSAStartup(MAKEWORD(2, 2), &wsaData);
	SOCKET sockServer = socket(AF_INET, SOCK_STREAM, 0);
	if (sockServer == INVALID_SOCKET)
	{
		std::cerr << "创建服务端句柄失败" << std::endl;
		WSACleanup();
		return -1;
	}
	printf("1. 创建服务端成功\n");
	SOCKADDR_IN addr = { 0 };
	addr.sin_family = AF_INET;
	addr.sin_port = htons(9870);
	addr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
	if (bind(sockServer, (SOCKADDR*)&addr, sizeof(SOCKADDR_IN)) == SOCKET_ERROR)
	{
		std::cerr << "绑定端口号失败" << std::endl;
		closesocket(sockServer);
		WSACleanup();
		return -1;
	}
	if (listen(sockServer, SOMAXCONN) == SOCKET_ERROR)
	{
		std::cerr << "监听端口号失败" << std::endl;
		closesocket(sockServer);
		WSACleanup();
		return -1;
	}
	std::cout << "服务器正在监听..." << std::endl;

	while (1)
	{
		fd_set reads;

		// 清空或者初始化reads
		FD_ZERO(&reads);

		// 设置sockServer到reads
		FD_SET(sockServer, &reads);

		for (auto v : g_clients)
		{
			FD_SET(v->clientSock, &reads);
		}
		int sRet = select(0, &reads, 0, 0, 0);

		// 表示select超时或者出错
		if (sRet <= 0) continue;

		if (FD_ISSET(sockServer, &reads)) {
			printf("服务端响应\n");
			SOCKADDR_IN clientAddr = {};
			int nAddrLen = sizeof(SOCKADDR_IN);
			SOCKET sockClient = accept(sockServer, (sockaddr*)&clientAddr, &nAddrLen);
			if (INVALID_SOCKET == sockClient) {
				printf("接收客户端连接失败\n");
				return -1;
			}
			std::cout << "开始处理客户端: " << std::endl;
			UserInfo* user = new UserInfo{ false, "undefined", sockClient };
			g_clients.push_back(user);
		}
		for (auto v : g_clients) {
			if (FD_ISSET(v->clientSock, &reads))
			{
				SelectClientConnection(v->clientSock, v);
			}
		}
	}
	closesocket(sockServer);
	WSACleanup();
	return 0;
}