libevent（10）使用event处理socket连接

news2024/9/26 3:32:20

这个例子中，我们通过event处理socket连接，并进行一些简单的数据处理。

代码如下 test_event_server.cpp：


#include <iostream>
#include <thread>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <event2/event.h>
#include <event2/listener.h>
#include <event2/thread.h>

#define SPORT 5001

using namespace std;

//正常断开连接、超时都会进入
void client_cb(evutil_socket_t s, short w, void *arg){
    //判断超时
	event* ev = (event*)arg;
	if(w & EV_TIMEOUT){
	    cout<<"timeout"<<endl;
		
		event_free(ev);
		evutil_closesocket(s);
        
        return;		
	}
	
    //需要清理event
	char buf[1024] = {0};
	int len = recv(s, buf, sizeof(buf) - 1, 0);
	if(len > 0){
	    cout<<buf<<endl;
		send(s, "ok", 2, 0);
	}else{
	    cout<<"event_free"<<endl;
		
		event_free(ev);
		evutil_closesocket(s);
	}
}

void listen_cb(evutil_socket_t s, short w, void *arg){
    cout<<"listen_cb"<<endl;
	
	sockaddr_in sin;
	socklen_t size = sizeof(sin);
	//读取连接信息
	evutil_socket_t client = accept(s,(sockaddr*)&sin, &size);
	char ip[16] = {0};
	evutil_inet_ntop(AF_INET, &sin.sin_addr, ip, sizeof(ip) - 1);
	cout<<"client ip is "<<ip<<endl;
	
	//客户端数据读取事件
	event_base* base = (event_base*)arg;
	event* ev = event_new(base, client, EV_READ|EV_PERSIST, client_cb, event_self_cbarg());
	//边缘触发
	//event* ev = event_new(base, client, EV_READ|EV_PERSIST|EV_ET, client_cb, event_self_cbarg());
	//10秒超时
	timeval t = {10, 0};
	event_add(ev, &t);
}

int main()
{
#ifdef _WIN32
    //windows初始化socket库
    WSADATA wsa;
    WSAStartup(MAKEWORD(2, 2), &wsa);
#else
    //发送数据给已关闭socket时,忽略管道信息.
    //否则可能导致程序dump.
    if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) {
        return -1;
    }
#endif
	//创建socket链接
	evutil_socket_t sock = socket(AF_INET, SOCK_STREAM, 0);
	if(sock <= 0){
	    cerr <<"socket error:"<<strerror(errno)<<endl;
		return -1;
	}
    
	//设置地址复用和非阻塞
	evutil_make_socket_nonblocking(sock);
	evutil_make_listen_socket_reuseable(sock);

	sockaddr_in sin;
	memset(&sin, 0 , sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_port = htons(SPORT);
	
	//绑定端口和地址
	int re = ::bind(sock,(sockaddr*)&sin, sizeof(sin));
	if(re != 0){
	    cerr<<"bind error:"<<strerror(errno)<<endl;
		return -1;
	}
	//开始监听
	listen(sock, 10);

    //创建 event_base 对象,一个 event_base 对象相当于一个 Reactor 实例
	event_base *base = event_base_new();
	
	//开始接收连接事件
	//默认水平触发
	event* socket_event = event_new(base, sock, EV_READ|EV_PERSIST, listen_cb, base);
	event_add(socket_event,0);

    event_base_dispatch(base);
    event_base_free(base);
	evutil_closesocket(sock);

#ifdef _WIN32
    //清理window的socket库
    WSACleanup();
#endif

    return 0;
}

代码在linux上执行，用telnet模拟客户端，并发送数据给server。在telnet超时10秒钟后，服务端自动断开连接。