C++ 高并发网络通信框架设计 基于 epoll 的多客户端事件驱动模型实战

class Connection {
public:
int fd;
std::string ip;
std::string buffer;Connection(int fd, const std::string& ip) : fd(fd), ip(ip) {}

void onRead();
void onWrite();
void onClose();
};

int epoll_fd = epoll_create1(0);
const int MAX_EVENTS = 1024;
epoll_event events[MAX_EVENTS];while (true) {
int n = epoll_wait(epoll_fd, events, MAX_EVENTS, -1);
for (int i = 0; i < n; ++i) {
int fd = events[i].data.fd;
if (fd == listen_fd) {
acceptNewConnection();
} else if (events[i].events & EPOLLIN) {
connectionMap[fd]->onRead();
} else if (events[i].events & (EPOLLHUP | EPOLLERR)) {
connectionMap[fd]->onClose();
}
}
}

int listen_fd = socket(AF_INET, SOCK_STREAM, 0);
setNonBlocking(listen_fd);sockaddr_in addr{};
addr.sin_family = AF_INET;
addr.sin_port = htons(8888);
addr.sin_addr.s_addr = INADDR_ANY;

bind(listen_fd, (sockaddr*)&addr, sizeof(addr));
listen(listen_fd, SOMAXCONN);

epoll_event ev{};
ev.data.fd = listen_fd;
ev.events = EPOLLIN;
epoll_ctl(epoll_fd, EPOLL_CTL_ADD, listen_fd, &ev);

void acceptNewConnection() {
while (true) {
sockaddr_in client_addr{};
socklen_t len = sizeof(client_addr);
int client_fd = accept(listen_fd, (sockaddr*)&client_addr, &len);
if (client_fd < 0) break;setNonBlocking(client_fd);

std::string ip = inet_ntoa(client_addr.sin_addr);
auto conn = std::make_shared<Connection>(client_fd, ip);
connectionMap[client_fd] = conn;

epoll_event ev{};
ev.data.fd = client_fd;
ev.events = EPOLLIN | EPOLLET;
epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client_fd, &ev);

std::cout << "新连接来自: " << ip << "n";
}
}

void Connection::onRead() {
char buf[4096];
while (true) {
ssize_t n = read(fd, buf, sizeof(buf));
if (n > 0) {
buffer.append(buf, n);
} else if (n == 0) {
onClose();
break;
} else {
if (errno == EAGAIN || errno == EWOULDBLOCK) break;
onClose();
break;
}
}if (!buffer.empty()) {
std::cout << "收到: " << buffer << "n";
write(fd, buffer.c_str(), buffer.size());
buffer.clear();
}
}

class IHandler {
public:
virtual void onMessage(Connection& conn, const std::string& data) = 0;
virtual void onConnect(Connection& conn) = 0;
virtual void onClose(Connection& conn) = 0;
};void registerHandler(std::shared_ptr<IHandler> h);

class EchoHandler : public IHandler {
public:
void onConnect(Connection& conn) override {
std::cout << "[连接建立] " << conn.ip << "n";
}void onMessage(Connection& conn, const std::string& data) override {
std::cout << "[收到数据] " << data << "n";
write(conn.fd, data.c_str(), data.size());
}

void onClose(Connection& conn) override {
std::cout << "[连接断开] " << conn.ip << "n";
}
};