libevent 的bufferevent和evconnlistener用法（echo示例）

libevent 的bufferevent和evconnlistener用法（echo示例）

#include <arpa/inet.h>
#include <errno.h>
#include <event2/buffer.h>
#include <event2/bufferevent.h>
#include <event2/event.h>
#include <event2/listener.h>
#include <event2/thread.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>

#define LISTEN_BACKLOG 10

static void acceptErr(struct evconnlistener *listener,void *);
static void accept_callbk(struct evconnlistener *listener,evutil_socket_t fd,struct sockaddr *sa,int , void *);

static void readSock(struct bufferevent* bev,void *);
static void sockEvent(struct bufferevent* bev,short events,void *);

int main(int argc,char **argv)
{
// base
struct event_base *base;
base = event_base_new();
if(!base)
{
fprintf(stderr,"new base error.\n");
return -1;
}

//准备一个地址结构体并初始化
struct sockaddr_in addr;
memset(&addr,0,sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = htonl(INADDR_ANY);
addr.sin_port = htons(9001);

//准备一个evconnlistenner
struct evconnlistener *listener;
//初始化 设置accept回调函数
listener = evconnlistener_new_bind(base,accept_callbk,NULL,
LEV_OPT_CLOSE_ON_FREE | LEV_OPT_REUSEABLE,
LISTEN_BACKLOG,
(struct sockaddr *)&addr,sizeof(addr));
if(!listener)
{
perror("listen:");
return -1;
}

//设置accept的出错处理函数
evconnlistener_set_error_cb(listener,acceptErr);

//进入事件循环
event_base_dispatch(base);
}

static void acceptErr(struct evconnlistener *listener,void *arg)
{
//获取base
struct event_base *base = evconnlistener_get_base(listener);
//获取错误字符
int err = EVUTIL_SOCKET_ERROR();

fprintf(stderr,"Get Error %d (%s)\n",err,evutil_socket_error_to_string(err));

event_base_loopexit(base,NULL);
//如果有多个监听，只把这个监听端口shutdown
}

//[4] accept
static void accept_callbk(struct evconnlistener *listener,evutil_socket_t fd,struct sockaddr *sa,int d, void *test)
{
//重要，获取base
struct event_base *base = evconnlistener_get_base(listener);

//获取client address
//struct sockaddr_in *clientsa = (sockaddr_in*) sa;

//下面是 bufferevent 的技术
struct bufferevent *bev = bufferevent_socket_new(base,fd,BEV_OPT_CLOSE_ON_FREE);

//可以对这个bev设置：read_callbk,write_callbk,event_callbk
bufferevent_setcb(bev,readSock,NULL,sockEvent,NULL);
bufferevent_enable(bev,EV_READ | EV_WRITE);

}

static void readSock(struct bufferevent* bev,void *tmp)
{
printf("read data \n");
//evutil_socket_t fd = bufferevent_getfd(bev);
struct evbuffer *input = bufferevent_get_input(bev);
struct evbuffer *output = bufferevent_get_output(bev);

evbuffer_add_buffer(output,input);  //假设是个echo 服务
}

static void sockEvent(struct bufferevent* bev,short event,void *ptr)
{
//出错处理
printf("sock Event \n");
if(event & BEV_EVENT_ERROR)
{
perror("Error form bufferevent");
}
if(event & (BEV_EVENT_EOF | BEV_EVENT_ERROR))
{
//获得socket
//int sockfd = bufferevent_getfd(bev);

bufferevent_free(bev);
}
}