Libevent网络库实现简单TCP服务端及客户端

Libevent简介

Libevent是一个用C语言编写的，轻量级的开源高性能事件通知库，主要有以下几个特点：事件驱动，高性能，轻量级，专注于网络，支持多平台，支持多种I/O复用技术，select，poll，epoll等，支持I/O定时器和信号事件，注册事件优先级。

服务端

#include "stdafx.h"
#include "event2/bufferevent.h"
#include "event2/buffer.h"
#include "event2/listener.h"
#include "event2/util.h"
#include "event2/event.h"
#include <event2/event-config.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <WinSock2.h>
#include <iostream>
#define IP_ADDRESS ("127.0.0.1")
#define PORT (8880)

// 连接
void accept_cb(int fd, short events, void* arg);
// 接收消息
void socket_read_cb(int fd, short events, void *arg);
// 初始化
int tcp_server_init(int port, int listen_num);

int main(int argc, char** argv)
{
	// 加载套接字库
	WSADATA wsaData;
	int iRet = 0;
	iRet = WSAStartup(MAKEWORD(2, 2), &wsaData);
	if (iRet != 0)
	{
		std::cout << "WSAStartup(MAKEWORD(2, 2), &wsaData) execute failed!" << std::endl;
		return -1;
	}
	if (2 != LOBYTE(wsaData.wVersion) || 2 != HIBYTE(wsaData.wVersion))
	{
		std::cout << "WSADATA version is not correct" << std::endl;
		WSACleanup();
		return -1;
	}
	int listener = tcp_server_init(PORT, 10);
	if (listener == -1)
	{
		perror("tcp_server_init error");
		return -1;
	}
	printf("server inti successful\n");
	struct event_base* base = event_base_new();
	// 添加监听客户端请求连接事件
	struct event* ev_listen = event_new(base, listener, EV_READ | EV_PERSIST,accept_cb, base);
	event_add(ev_listen, NULL);
	
	event_base_dispatch(base);
	WSACleanup();
	return 0;
	return 0;
}
// 连接
void accept_cb(int fd, short events, void* arg)
{
	evutil_socket_t sockfd;
	struct sockaddr_in client;
	socklen_t len = sizeof(client);
	sockfd = ::accept(fd, (struct sockaddr*)&client, &len);
	evutil_make_socket_nonblocking(sockfd);
	printf("accept a client %d\n", sockfd);
	struct event_base* base = (event_base*)arg;
	// 仅仅是为了动态创建一个event结构体
	struct event* ev = event_new(NULL, -1, 0, NULL, NULL);
	// 将动态创建的结构体作为event的回调参数
	event_assign(ev, base, sockfd, EV_READ | EV_PERSIST,socket_read_cb, (void*)ev);
	event_add(ev, NULL);
}
// 接收消息
void socket_read_cb(int fd, short events, void *arg)
{
	char msg[4096];
	struct event* ev = (struct event*)arg;
	int len = recv(fd, msg, sizeof(msg) - 1, 0);
	if (len <= 0)
	{
		printf("some error happen when read\n");
		event_free(ev);
		closesocket(fd);
		return;
	}
	msg[len] = '\0';
	printf("recv the client msg : %s\n", msg);
	char reply_msg[4096] = "I have recvieced the msg: ";
	strcat(reply_msg + strlen(reply_msg), msg);

	int ret = send(fd, reply_msg, strlen(reply_msg), 0);
}
// 初始化
int tcp_server_init(int port, int listen_num)
{
	int errno_save;
	int listener;
	listener = ::socket(AF_INET, SOCK_STREAM, 0);
	if (listener == -1)
		return -1;
	// 允许多次绑定同一个地址。要用在socket和bind之间
	evutil_make_listen_socket_reuseable(listener);
	struct sockaddr_in sin;
	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = 0;
	sin.sin_port = htons(port);
	if (::bind(listener, (struct sockaddr*)&sin, sizeof(sin)) < 0) 
	{
		errno_save = errno;
		evutil_closesocket(listener);
		errno = errno_save;
		return -1;
	}
	if (::listen(listener, listen_num) < 0)
	{
		errno_save = errno;
		evutil_closesocket(listener);
		errno = errno_save;
		return -1;
	}
	// 跨平台统一接口，将套接字设置为非阻塞状态
	evutil_make_socket_nonblocking(listener);
	return listener;
}

客户端

#include "stdafx.h"
#include "event2/bufferevent.h"
#include "event2/buffer.h"
#include "event2/listener.h"
#include "event2/util.h"
#include "event2/event.h"
#include <event2/event-config.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <WinSock2.h>
#include <iostream>
#define IP_ADDRESS ("127.0.0.1")
#define PORT (8880)

// 连接服务器
int tcp_connect_server(const char* server_ip, int port);
DWORD WINAPI Fun1Proc(LPVOID lpParameter);
// 发送消息
void cmd_msg_cb(int fd, char* msg);
// 接收消息
void socket_read_cb(int fd, short events, void *arg);

int main(int argc, char** argv)
{
	// 加载套接字库
	WSADATA wsaData;
	int iRet = 0;
	iRet = WSAStartup(MAKEWORD(2, 2), &wsaData);
	if (iRet != 0)
	{
		return -1;
	}
	if (2 != LOBYTE(wsaData.wVersion) || 2 != HIBYTE(wsaData.wVersion))
	{
		WSACleanup();
		return -1;
	}
	// 连接服务器
	int sockfd = tcp_connect_server(IP_ADDRESS, PORT);
	if (sockfd == -1)
	{
		perror("tcp_connect error");
		return -1;
	}
	printf("connect to server successful\n");
	struct event_base* base = event_base_new();
	struct event* ev_sockfd = event_new(base, sockfd, EV_READ | EV_PERSIST, socket_read_cb, NULL);
	event_add(ev_sockfd, NULL);

	// 创建线程发送数据
	HANDLE hThread1 = CreateThread(NULL, 0, Fun1Proc, (void*)sockfd, 0, NULL);
	CloseHandle(hThread1);

	event_base_dispatch(base);
	WSACleanup();
	printf("finished \n");
	return 0;
}
// 发送消息
DWORD WINAPI Fun1Proc(LPVOID lpParameter)
{
	char t_cin[1024];
	int sockfd = (int)lpParameter;
	while (1)
	{
		memset(t_cin, 0, 1024);
		std::cin >> t_cin;
		if (strcmp(t_cin, "exit") == 0)
		{
			break;
		}
		cmd_msg_cb(sockfd, t_cin);
	}
	exit(1);
	return 0;
}
void cmd_msg_cb(int fd, char* msg)
{
	int ret = send(fd, (const char*)msg, strlen((char*)msg), 0);
	if (ret <= 0)
	{
		perror("read fail ");
		return;
	}
	printf("send:%s\n", (char*)msg);
}
// 接收消息
void socket_read_cb(int fd, short events, void* arg)
{
	char msg[1024];
	// 为了简单起见，不考虑读一半数据的情况
	int len = recv(fd, msg, sizeof(msg) - 1, 0);
	if (len <= 0)
	{
		perror("read fail");
		exit(1);
	}
	msg[len] = '\0';
	printf("recv:%s\n", msg);
}
// 连接服务器
int tcp_connect_server(const char* server_ip, int port)
{
	int sockfd, status, save_errno;
	SOCKADDR_IN server_addr;
	memset(&server_addr, 0, sizeof(server_addr));
	server_addr.sin_family = AF_INET;
	server_addr.sin_addr.s_addr = inet_addr(server_ip);
	server_addr.sin_port = htons(port);
	
	sockfd = ::socket(PF_INET, SOCK_STREAM, 0);
	if (sockfd == -1)
	{
		return sockfd;
	}
	status = ::connect(sockfd, (struct sockaddr*)&server_addr, sizeof(server_addr));
	if (status == -1)
	{
		save_errno = errno;   // 清理  
		closesocket(sockfd);
		errno = save_errno; // the close may be error  
		return -1;
	}
	evutil_make_socket_nonblocking(sockfd);
	return sockfd;
}